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  • growth  (107)
  • Coleoptera
  • Springer  (185)
  • Institute of Physics
  • 1995-1999  (98)
  • 1990-1994  (87)
  • 1940-1944
  • 1996  (98)
  • 1993  (87)
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  • 1995-1999  (98)
  • 1990-1994  (87)
  • 1940-1944
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  • 1
    ISSN: 1570-7458
    Keywords: Vitis vinifera ; Empoasca vitis ; leafhopper ; photosynthesis ; transpiration ; stomatal conductance ; mesophyll conductance ; growth ; yield ; fruit quality ; starch ; carbohydrate reserves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The impact of the grape leafhopper,Empoasca vitis, on leaf gas exchange, plant growth, yield, fruit quality and carbohydrate reserves of the grapevines,Vitis vinifera L., was studied. Gas exchange was measured on the discolored (red) and the green parts of infested main leaves and on leaves from uninfested vines. Photosynthesis and mesophyll conductance were severely reduced on main leaves showing leafhopper feeding symptoms. The stomatal conductance of the red leaf section of infested main leaves was lower than on undamaged control leaves. Additionally, the red leaf section of infested main leaves showed lower transpiration rates when compared to the green parts of the same leaves and to undamaged control leaves. Gas exchange processes of lateral leaves were not affected by leafhopper feeding. Leafhopperload on main leaves was correlated to visual damage symptoms. At 71.8 leafhopper-days per leaf up to 40% of the main leaf area of the infested plants was discolored from the borders towards the center. Lateral leaves showed no feeding symptoms. Shoot diameter, pruning weight and carbohydrate reserves in the wood were not affected by leafhoppers. Lateral leaf area growth was significantly stimulated on plants infested by leafhoppers. No decrease in yield and fruit quality with leafhopper-loads up to 71.8 leafhopper-days per leaf were observed.
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  • 2
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    Entomologia experimentalis et applicata 80 (1996), S. 141-144 
    ISSN: 1570-7458
    Keywords: Polygonia c-album ; Nymphalidae ; host-plant selection ; growth ; size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 3
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    Entomologia experimentalis et applicata 80 (1996), S. 453-460 
    ISSN: 1570-7458
    Keywords: Coleoptera ; Curculionidae ; Metamasius hemipterus ; aggregation pheromone ; redundancy ; field trapping ; sex-ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The five synthetic pheromone components of the West Indian sugarcane borer (WISB), Metamasius hemipterus (L.) (Coleoptera, Curculionidae) were tested in the field. The combination of sugarcane (SC) and the major pheromone compound, 4-methyl-5-nonanol (1) was attractive. However, the addition of 2-methyl-4-heptanol (2) or 2-methyl-4-octanol (3) was required to reach high catch levels while 5-nonanol (4) or 3-hydroxy-4-methyl-5-nonanone (5) did not enhance WISB attraction. The redundancy phenomenon, here reported for the first time in rhynchophorinous species, was observed between compounds 2 and 3. SC +1 +3 was more attractive than living male baits, however, the sex-ratio of the catches was equivalent between both treatments. The sex-ratio of catches was affected by the qualitative composition of the pheromone formulation. Compound 3 had a sexual role, attracting more females while 5 seemed to play an aggregation role, luring both sexes in the same proportion.
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  • 4
    ISSN: 1570-7458
    Keywords: Oryzaephilus surinamensis ; Coleoptera ; Cucijidae ; population density ; semiochemicals ; lethal secretions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 5
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    Entomologia experimentalis et applicata 69 (1993), S. 13-20 
    ISSN: 1570-7458
    Keywords: Artificial diets ; Coccinellidae ; rearing ; biological control ; Chilocorus spp. ; Coleoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Promising diets were screened and the most successful modified with additives used in artificial diets for other entomophagous insects. Two suitable diets were obtained, one for adults and one for larvae ofChilocorus nigritus (Fabricius) (Coleoptera: Coccinellidae). They were still inferior to natural prey and not adequate as the sole food source for rearing consecutive generations. They are valuable as substitute food in the insectary during shortages of natural prey. Oleander scaleAspidiotus nerii Bouché andAsterolecanium miliaris (Boisduval) were evaluated as natural prey forC. nigritus and two other potential biocontrol agents in southern Africa,C. bipustulatus (Linnaeus) andC. infernalis Mulsant.A. nerii andA. miliaris were suitable for all life stages ofC. nigritus and adults ofC. bipustulatus andC. infernalis. A. miliaris was inadequate for larvae ofC. bipustulatus andC. infernalis.
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  • 6
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    Entomologia experimentalis et applicata 79 (1996), S. 335-344 
    ISSN: 1570-7458
    Keywords: alkaloid ; developmental time ; early instars ; growth ; Manduca sexta ; molting duration ; phenolics ; plant-herbivore interactions ; thermal regime
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To understand the mechanisms underlying plant-insect herbivore interactions, it is necessary to examine the simultaneous effects of temperature, food quality and larval age. We examined the simultaneous effects of three allelochemicals (tomatine, rutin and chlorogenic acid) on the performance of first and second instar Manduca sexta larvae under two representative thermal regimes 21 : 10°C and 26 : 15°C for spring and summer, respectively. Thermal regime and allelochemicals interacted to influence the time from egg hatch to ecdysis to the third instar. On average, it took about half as much time to reach the third instar at 26 : 15°C as it did at 21 : 10°C. Separately, tomatine and rutin had a negative effect on developmental time from egg hatch to the third instar, but their simutaneous effects were not additive. Chlorogenic acid significantly reduced the negative effect of tomatine. The magnitude of the allelochemical effect was larger at the cooler thermal regime compared to the warmer regime. For instance, chlorogenic acid by itself had no effect at the 26 : 15°C regime, but at the 21 : 10°C regime it significantly shortened total developmental time. The effect of chlorogenic acid on stadium duration was distinctly different for the two instars. Chlorogenic acid shortened stadium duration of first instar larvae. However, depending on thermal regime and the presence of tomatine, chlorogenic acid had a negative, positive or neutral effect on stadium duration of second instar larvae. Molting duration of second instar larvae was shortened by a half day at the warmer thermal regime but was not affected by the allelochemicals. Final larval weight was influenced by rutin and chlorogenic acid. Caterpillars fed diets containing 20 μmoles of rutin were on average 10% lighter than those fed plain diet, whereas those fed diets containing 20 μmoles of chlorogenic adic were on average 7% heavier. However, the effect of chlorogenic acid depended on thermal regime. Overall, our results indicated that: 1) temperature and food quality can interact to influence insect performance and 2) these effects are influenced by larval age.
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  • 7
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    Entomologia experimentalis et applicata 79 (1996), S. 355-362 
    ISSN: 1570-7458
    Keywords: aerial pollution ; heavy metals ; sulphur dioxide ; feeding preference ; Salix ; Melasoma lapponica ; Coleoptera ; Chrysomelidae ; population density ; induced resistance ; plant communication ; Kola Peninsula
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We studied preference for willows along a pollution gradient on the Kola Peninsula, Russia, by the leaf beetle, Melasoma lapponica. Multiple tests with leaf disks demonstrated low preference for Salix borealis, S. caprea and S. phylicifolia from the plot situated 14 km from the smelter, in comparison with conspecific plants from plots situated at 1 and 29 km distances. This pattern was observed when testing beetles orginating from any plot both in 1993 and 1994, using both young and mature leaves of S. borealis. Although fumigation of S. borealis with realistic SO2 concentration (100 μg/m3) increased plant palatability, preference for plants from our study plots did not correlate with plot-specific mean SO2 concentrations. Furthermore, no correlation with foliar concentrations of the main metal pollutants (Ni and Cu) was found. Palatability of plants was negatively correlated with population density of M. lapponica, which peaked in the moderately polluted plot 14 km from the smelter. Within this plot, beetles clearly preferred non-damaged bushes of S. borealis to previously damaged bushes. We therefore conclude that low preference of S. borealis from the moderately polluted area was caused by plant resistance induced by severe damage from M. lapponica in previous years rather than by pollution impact. However, S. caprea and S. phylicifolia had little damage from M. lapponica, and low palatability of these species in the moderately polluted plot suggests changes in plant quality similar to changes in heavily damaged bushes of S. borealis.
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  • 8
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    Entomologia experimentalis et applicata 80 (1996), S. 160-162 
    ISSN: 1570-7458
    Keywords: Phyllotreta nemorum ; Barbarea vulgaris ; Coleoptera ; Chrysomelidae ; Cruciferae ; resistance ; genetics of insects ; inheritance ; Y-linkage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 9
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    Entomologia experimentalis et applicata 80 (1996), S. 443-451 
    ISSN: 1570-7458
    Keywords: beta-carboline alkaloid ; Trichoplusia ni ; harmane ; harmaline ; amitriptyline ; imipramine ; monoamine oxidase inhibitor ; tricyclics ; growth ; feeding behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this study we investigated the effects of two naturally occurring beta-carboline alkaloids and two synthetic tricyclic antidepressants on the growth and food consumption of fifth instar larvae of the cabbage looper, Trichoplusia ni Hübner (Lepidoptera: Noctuidae). In artificial diets at high concentrations (3,000 ppm), harmane, amitriptyline, and imipramine reduce growth and feeding; harmane reduced feeding consistently at a lower concentration (200 ppm). In animals other than insects, beta-carboline alkaloids inhibit monoamine oxidase (MAO) activity and thus affect rates of disposition of serotonin and other monoamine neurotransmitters. Because brain serotonin levels are associated with variation in rates of carbohydrate and protein intake in insects, the effects of beta-carboline alkaloid ingestion on dietary self-selection behavior were examined. Choosing between diets lacking carbohydrate but containing protein and diets lacking protein but containing carbohydrate, larvae consumed a greater proportion of diet containing protein but lacking carbohydrate in the presence of harmane than in its absence. These results are consistent with beta-carboline alkaloid-mediated persistence of serotonin in the brain due to MAO inhibition. Alternatively, these results could reflect alkaloid-mediated peripheral inhibition of sucrose taste receptors influencing ingestive behaviors. That beta-carboline alkaloid ingestion is associated with changes in feeding behavior is consistent with a possible defensive role for these compounds in plant foliage.
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  • 10
    ISSN: 1570-7458
    Keywords: Chrysoperla carnea ; food consumption ; growth ; development ; efficiency of food utilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Larvae of the common green lacewing,Chrysoperla carnea (Stephens)(Neuroptera: Chrysopidae), were fed either an optimal or a suboptimal number of eggs of the mothAnagasta kuehniella (Zeller) in the first and/or second larval instar, or in all three larval instars. Parameters for the duration, growth, and the efficiency of conversion of ingested food to body substance (ECI) of each instar were established for seven different dietary regimes. Larvae that had a suboptimal food supply in the first instar had a significantly longer developmental time, gained significantly less weight, and had a slightly lower ECI in that instar larvae. Suboptimally-fed second less, but remained only slightly longer in that instar and had a similar ECI to optimally-fed second instar larvae. The developmental time of suboptimally-fed third instar larvae was similar to that of optimally-fed larvae of that stage. Whereas the growth of the former was significantly less than that of larvae optimally fed in that instar, the ECI of the former was significantly higher. Despite the relatively smaller size of larvae fed suboptimally in the first and/or second instar, when such larvae were subsequently supplied with an overabundance of prey eggs, they consumed approximately the same number of eggs during the remainder of their larval life as did larvae whose food supply had not been restricted previously. When larvae were allowed to consume different numbers of eggs in their third instar, their gain in weight and therefore the weights attained by the resulting adults (based on the weights of 3-day-old cocoons) had a highly significant positive correlation with the number of eggs consumed in this instar.
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  • 11
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    Entomologia experimentalis et applicata 67 (1993), S. 135-142 
    ISSN: 1570-7458
    Keywords: nutrition ; utilization ; efficiency ; growth ; metabolism ; energy ; respirometry ; Pieris
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Conventional gravimetry and a combination of gravimetry and respirometry were compared for their precision in measuring respiration and metabolic efficiency of growth of final stadiumPieris brassicae L. (Pieridae, Lepidoptera) caterpillars. This was done both for caterpillars feeding on an artificial diet and for caterpillars feeding on excised leaf material of a host plant,Brassica oleracea L. Gravimetry produced significantly greater variation in the total amount of matter respired and the metabolic efficiency than indirect calorimetry for caterpillars feeding on plant material, while the two methods gave similar results for the caterpillars reared on a meridic artificial diet. Respirometry (indirect calorimetry) revealed that caterpillars feeding on the artificial diet were growing with a higher metabolic efficiency than caterpillars feeding on the host plant. This difference was not revealed by conventional gravimetry. It is argued that metabolic efficiencies as derived from gravimetric budget calculations are subject to a number of random errors that distort precise determination of metabolic efficiencies in studies involving plant food.
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  • 12
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    Entomologia experimentalis et applicata 66 (1993), S. 161-169 
    ISSN: 1570-7458
    Keywords: avoidance behaviour ; capture efficiency ; Coleoptera ; time-lapse video ; visual recording
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pitfall trap capture forSitophilus oryzae (L.),S. zeamais (Motschulsky),S. granarius (L.),Tribolium confusum (Duval),T. castaneum (Herbst);Oryzaephilus surinamensis (L.),Cryptolestes pusillus (Schonherr),Rhyzopertha dominica (Fabr.), andProstephanus truncatus (Horn) in millet was assessed by visual and time-lapse video recordings. The behaviour of different beetle species in arenas containing millet was monitored over 24 h and the frequency of encounters with the trap rim resulting in capture recorded. The capture efficiency of four types of pitfall traps (i.e. polystyrene, polythene, glass and tin-plated steel can) with rims exposed or submerged below the millet surface level were compared. Capture was related to beetle size, locomotory rate, and beetle behaviour at the trap rim as well as trap design and placement. The lighter and smaller species were least captured. Glass jars were more effective than plastic and metal containers. Traps placed with their rims submerged below the grain surface level were more efficient than those with rims exposed. Capture rate was unrelated to trap size. The frequency of encounters with trap rims was not correlated with capture rate. Three types of avoidance behaviours at the trap rims i.e. probing, skirting and spontaneous retreat, were related to capture rate, spontaneous retreat being the most effective escape mechanism and probing least.
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  • 13
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    Entomologia experimentalis et applicata 66 (1993), S. 191-196 
    ISSN: 1570-7458
    Keywords: Leptinotarsa decemlineata (Say) ; Coleoptera ; Chrysomelidae ; distribution ; diapause ; overwintering ; mortality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 14
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    Entomologia experimentalis et applicata 80 (1996), S. 231-237 
    ISSN: 1570-7458
    Keywords: Leptosphaeria maculans ; Peronospora parasitica ; fungal pathogens ; Phyllotreta cruciferae ; flea beetles ; Coleoptera ; Chrysomelidae ; Cruciferae ; chitinase ; myrosinase ; allocation costs ; plant defense mechanisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We used artificial selection experiments to study genetic allocation costs and physiological mechanisms of resistance to herbivory and fungal disease. Genetic costs to resistance were present in some instances and absent in others. Genetic resistance to the fungal pathogen, Leptosphaeria maculans was cost-free, while resistance to Peronospora parasitica showed a negative genetic correlation between disease resistance and growth rate. Leptosphaeria resistant genotypes had 13% higher chitinase activity. Genetic increases in myrosinase activity were correlated with increased resistance to flea beetles (Phyllotreta cruciferae), but resulted in lower plant fecundity, presumably due to production costs of myrosinase. Genetic costs of resistance may maintain genetic variation in natural plant populations. These studies demonstrate the predictive and explanatory power of a functional approach to plant-herbivore and plant-pathogen interactions.
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  • 15
    ISSN: 1570-7458
    Keywords: ectoparasitoids ; semiochemicals ; parasite host-selection ; Eupelmus vuilleti ; Hymenoptera ; Eupelmidae ; Dinarmus basalis ; Pteromalidae ; Coleoptera ; Bruchidae ; Bruchidius atrolineatus
    Source: Springer Online Journal Archives 1860-2000
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  • 16
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    Entomologia experimentalis et applicata 80 (1996), S. 311-314 
    ISSN: 1570-7458
    Keywords: leaf beetles ; Coleoptera ; Chrysomelidae ; feeding preference ; mating ; willows ; Salix
    Source: Springer Online Journal Archives 1860-2000
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  • 17
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    Entomologia experimentalis et applicata 81 (1996), S. 47-51 
    ISSN: 1570-7458
    Keywords: southern corn rootworm ; plant-insect interaction ; plant chemistry ; Coleoptera ; Chrysomelidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of host plant and dietary cucurbitacin on the growth of larval southern corn rootworm (SCR), Diabrotica undecimpunctata howardi Barber (Chrysomelidae: Luperini), were investigated. SCR were reared on four hosts: corn, Zea mays; peanuts, Arachis hypogaea; and two squash varieties, Cucurbita pepo cv. Ambassador (containing cucurbitacin D (0.08 mg g−1 fr.wt.) = bitter), and C. pepo cv. Early Yellow Crookneck (lacking cucurbitacin = non-bitter). Larval growth was significantly greater on corn and peanuts than on either squash variety. After four weeks, adults had emerged from corn and peanut plants, while squash-reared larvae had not yet entered the pupal stage. There was no difference in larval growth on the two varieties of squash. Primary metabolite measurements showed no nutritional differences between the two squash varieties. Artificial diet experiments were used to test the effect of three concentrations of cucurbitacin D (0.0, 0.1, and 0.6 mg g−1 diet) on growth of larval SCR. Larvae reared on diet containing 0.6 mg g−1 cucurbitacin weighed significantly less than larvae reared on diet containing 0.1 mg g−1 or no cucurbitacin after 10 d. No significant difference in growth was measured between the 0.1 mg g−1 diet and the 0.0 mg g−1 diet. Results are discussed relative to theories about the relationship between diabroticites and cucurbitacins.
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  • 18
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    Entomologia experimentalis et applicata 79 (1996), S. 9-17 
    ISSN: 1570-7458
    Keywords: Anthonomus pomorum ; temperature ; diel cycle ; Coleoptera ; Curculionidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Individual pairs of overwintered adult apple blossom weevils, Anthonomus pomorum (L.), confined with apple twigs under different ambient temperatures in the laboratory and on apple trees in the field, were observed through day and night for their spring activities. Flight behavior in relation to ambient temperature was also investigated under laboratory conditions using flight stands. Both sexes displayed predominantly nocturnal behavior patterns in both the laboratory and the field. Feeding, crawling, and mating activities increased following sunset in the field or onset of scotophase in the laboratory while resting occurred most frequently during daylight hours. Results of the laboratory experiments showed that temperature affected significantly the activity patterns. The diel pattern of activities became less distinctive at higher temperatures (above 15°C), and total activities in crawling, feeding, and mating were suppressed significantly at lower temperatures (below 5°C). Over 97% of the test weevils initiated take-off response from flight stands at 20°C within the 30 min trial period; however, flight initiation rarely occurred at temperatures 12°C or below. Overall, results of the laboratory and field experiments indicate that A. pomorum is a remarkably cold-adapted insect with ability to crawl, feed, and mate at a few degrees above freezing, a physiological attribute necessary for the exploitation of early stages of apple bud development in the cold early spring.
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  • 19
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    Entomologia experimentalis et applicata 80 (1996), S. 409-414 
    ISSN: 1570-7458
    Keywords: Coleoptera ; Scarabaeidae ; Antitrogus consanguineus ; Antitrogus parvulus ; avidin ; snowdrop lectin ; wheatgerm lectin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Snowdrop and wheatgerm lectins were found to be insecticidal and growth inhibiting dietary proteins for larvae of the sugarcane whitegrub Antitrogus parvulus. At concentrations as low as 0.5 mg of snowdrop lectin per gram of semi-artificial diet, growth was inhibited by 21 days of feeding and significant mortality was apparent by 28 days. Wheatgerm lectin was active at similar concentrations, although expression of the effects was slower. Avidin was found to be a growth inhibiting dietary protein for larvae of Antitrogus consanguineus. At levels as low as 0.01 mg g-1 of diet, growth was inhibited by 28 days of feeding. Avidin caused no significant mortality after 35 days of feeding. Snowdrop and wheatgerm lectins and avidin are insect growth-inhibiting proteins whose genes potentially could be manipulated into sugarcane and improve host-plant resistance to whitegrubs.
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  • 20
    ISSN: 1572-8889
    Keywords: Prostephanus truncatus ; larger grain borer ; Coleoptera ; Bostrichidae ; flight ; stored product insect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Higher flight activity has been observed in aged, high-density cultures ofProstephanus truncatus (Horn) (Coleoptera: Bostrichidae), but adults in new, lowdensity culture jars showed less flight activity. In order to understand this change in behavior, the effects of population density, age, resource quality, and sex on the flight ofP. truncatus were studied in a wind tunnel. While an immediate density on the release platform had no significant effect on flight, beetles from high-density cultures were more inclined to fly than those from low-density cultures. Resource quality exerted a major influence on flight; insects in food suitable for boring and oviposition seldomly exhibited flight, however, when food was absent or of inferior quality for boring and oviposition, the dominant behavior was flight. Also, insects maintained for a week in food suitable for boring and oviposition were less ready to fly than those maintained in food unsuitable for boring and oviposition. The optimum age range for flight activity was before the peak of reproduction and insects rarely flew before 4 days or after 32 days of emergence. There were no significant differences between the flight activity of males and that of females. Based on these results, we conclude that age and resource quality are major influences on the flight activity ofP. truncatus and a hypothesis is proposed in which reproductively active male and female beetles disperse from habitats of low resource quality to those that support their reproductive behavior. The practical implications of these results and the possible role of the male-produced aggregation pheromone are discussed.
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  • 21
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    Entomologia experimentalis et applicata 68 (1993), S. 9-13 
    ISSN: 1570-7458
    Keywords: bioassay ; behavioural response ; Coleoptera ; carob extract ; stored product
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The behavioural responses ofCryptolestes pusillus Oryzaephilus surinamensis andProstephanus truncatus to different doses of carob extract were assessed in a two-choice pitfall bioassay and in plastic grain probe traps. The extract evoked a quick directional response and induced high beetle attraction to treated pitfall arenas compared with the controls. Overall, the extract improved probe trap efficiency by about 50% compared to unbaited probes. Beetle response was dose-dependent with the medium dose of 10 μl probably eliciting optimum response.
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  • 22
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    Cellular and molecular life sciences 49 (1993), S. 171-174 
    ISSN: 1420-9071
    Keywords: Coleoptera ; Meloidae ; Epicauta funebris ; chemical defense ; biosynthesis ; terpenoid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Cantharidin, a potent defensive chemical, is present in all ten life stages of the blister beetleEpicauta funebris. The first five larval stages accumulate cantharidin as they feed and grow in size. When disturbed, they exude cantharidin in a milky oral fluid, not in hemolymph which adult beetles reflexively discharge from leg joints. Two subsequent larval stages and the pupa do not feed, grow, regurgitate, or change in their defensive reserves (110 μg cantharidin/insect, regardless of sex). Adult beetles kept in isolation for 60–90 d exhibit a pronounced sexual dimorphism in cantharidin production: the male biosynthesizes about 17 mg of the toxin, representing 10% of his live weight, whereas the female actually loses most of her defensive reserves. But in the wild a female beetle repeatedly acquires cantharidin as copulatory gifts from her mates.
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  • 23
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    Cellular and molecular life sciences 49 (1993), S. 272-275 
    ISSN: 1420-9071
    Keywords: Semiochemical ; pheromone ; host selection ; competition ; Coleoptera ; Scolytidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Bark beetles,Ips typographus andPityogenes chalcographus, attracted by synthetic or natural pheromone to Norway spruce logs,Picea abies, preferred to colonize uninfested logs rather than logs occupied by these beetles, probably as a means of avoiding intra-and interspecific competition. The aggregation pheromone components ofP. chalcographus, chalcogran and methyl (E, Z)-2,4-decadienoate, inhibited the attraction response ofI. typographus to its pheromone components (methyl butenol andcis-verbenol), while the converse was not true. However, verbenone released from colonized bark inhibited pheromonal response ofP. chalcographus.
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  • 24
    ISSN: 1420-9071
    Keywords: Coleoptera ; Coccinellidae ; Subcoccinella-24-punctata ; chemical defense ; quinoline alkaloid ; Nα-quinaldyl-L-arginine·HCl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The isolation of Nα-quinaldyl-L-arginine·HCl (1) from the CoccinellidaeSubcoccinella-24-punctata is reported. The structure, first established on the basis of the analysis of the spectral properties of1, has been confirmed by synthesis. The alkaloid is of endogenous origin and markedly deterrent to ants.
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  • 25
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    Chemoecology 4 (1993), S. 29-32 
    ISSN: 1423-0445
    Keywords: chemical defence ; alkaloids ; predation ; Coleoptera ; Coccinellidae ; Adalia bipunctata ; Coccinella septempunctata ; Hymenoptera ; Formicidae ; Lasius niger
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Garden black ants,Lasius niger L., in a laboratory colony, attacked three species of live ladybirds found near their nest, killing the smaller two species. A second colony was offered artificial diets containing crushed ladybirds of two species, and the ants' choice of feeding site noted. Both the diets were aversive compared to control, but that containing 7spot,Coccinella septempunctata L., was more aversive than the diet containing 2spot,Adalia bipunctata L. The implications of this lesser protection for 2spots in terms of the chemical defence of the species are discussed.
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  • 26
    ISSN: 1423-0445
    Keywords: herbivory ; plant resistance ; leaf colour ; leaf toughness ; tree growth rate ; leaf nutrients ; terpenes ; Coleoptera ; Chrysomelidae ; Paropsinae ; Chrysophtharta bimaculata ; Myrtaceae ; Eucalyptus regnans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In bagged and unbagged shoot experiments, we investigated the survival and growth rate of first instar larvae ofChrysophtharta bimaculata on 9 families of a natural host,Eucalyptus regnans. Families used had been previously assessed as being either of low or high susceptibility toC. bimaculata damage. In conjunction with larval experiments, we measured 24 tree and leaf characteristics (including foliar elemental concentrations, foliar terpenes, leaf toughness and tree growth rates) and attempted to correlate the plant characters measured with differences in larval performance and previous scorings ofE. regnans family susceptibility. First instar larval growth and survival did not differ significantly across families or between low and high susceptibility family groups (=susceptibility classes), although survival was significantly greater in bagged than unbagged treatments. As predators were in low abundance at the study site, we attribute higher survival rates of larvae in bagged treatments to increased protection from adverse weather conditions. Only one plant character measured, an unidentified foliar phlorglucinol, was significantly negatively correlated with larval survival. Of the 24 plant characters measured, 11 were significantly different between families and 10 were signficantly different between susceptibility classes. Only 4 plant characters were significantly different at both the family and susceptibility class levels;viz. proportion red leaves, tree height at end of season, trunk volume at end of season and relative growth rate based on tree height. Principle Component Analysis using all plant characters measured, or subsets of them, could not separate individual families or susceptibility classes. Our results suggest that herbivore resistance mechanisms inE. regnans do not affectC. bimaculata larvae, but may influence adult feeding and/or oviposition.
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  • 27
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    Aquatic sciences 55 (1993), S. 76-86 
    ISSN: 1420-9055
    Keywords: Sa velinus alpinus ; growth ; Lake Geneva ; latitude ; eutrophication ; fish density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The growth rate of the Arctic charr,Salvelinus alpinus (L.), is exceptionally high in Lake Geneva; one of the highest every recorded. This can be explained by three factors: (1) the Arctic charr of Lake Geneva is the most southerly indigenous population in the world, (2) the trophic resources are important because of the eutrophication of the lake, (3) the fish density is low.
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  • 28
    ISSN: 1423-0445
    Keywords: male aggression ; defensive secretion ; tergal gland ; closed-loop-stripping-analyses ; tandem bioassay ; mass fragmentography ; 2-methyl-1,4-benzoquinone ; Coleoptera ; Staphylinidae ; Aleochara curtula
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 2-methyl-1,4-benzoquinone as a target compound of the tergal gland secretion of the rove beetle,Aleochara curtula, was quantified from the reservoirs of individual beetles. Males store less secretion than females, and they evaporate more of the secretion as measured by adsorption from the air (closed-loop-stripping-analysis). The amount of emitted quinone is increased during aggressive interactions of rival males. The pulsed emission of the secretion during aggression is demonstrated by a novel technique combining observation of behavior with the on-line measurement of target fragment ions by mass-spectrometry (tandem bioassay — mass fragmentography). The emission of the secretion is used as a weapon in combats between males and may result in the repulsion of subordinate males from the mating site, but may also serve to mimic females chemically in order to avoid aggressive encounters.
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  • 29
    ISSN: 1423-0445
    Keywords: chemical defense ; predator-prey interaction ; synergism ; Coleoptera ; Staphylinidae ; Oxytelinae ; Bledius ; Carabidae ; Dyschirius ; Pogonus ; Dichirotrichus ; Formicinae ; Cataglyphis ; Dermaptera ; Labidura
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The adaptation of defensive secretions to their target organisms was examined for the abdominal gland secretions ofBledius furcatus, B. spectabilis andB. arenarius. Therefore the target organisms of the secretion of theseBledius species (i.e. their predators) had to be identified. At the collection sites examined these were the earwigLabidura riparia, the antCataglyphis bicolor, the flyLispe candicans, different carabids of the generaPogonus, Dichirotrichus, Dyschirius, Bembidion andCalathus and the wading birdsHaematopus ostralegus andCalidris alba. The secretion of the abdominal glands contains the toxin ptoluquinone dissolved in eitherγ-dodecalactone and 1-undecene (B. furcatus andB. spectabilis) or in octanoic acid and octyloctanoate (B. arenarius). The ratio of these solvents is species-specific. Application experiments using some of the natural insect predators (L. riparia, C. bicolor, Pogonus, Di. gustavii, Dyschirius) revealed that these solvent ratios provided a more effective deterrent than other possible ratios. Thus by combining the solvents in certain ratios, the capability of cuticular penetration and therefore the effectiveness of the defensive secretions are adapted to their natural targets.
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  • 30
    ISSN: 1423-0445
    Keywords: kairomone ; behavior ; cucurbitacin ; Cucurbitaceae ; Coleoptera ; Chrysomelidae ; Luperini ; Aulacophora ; Diabrotica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The attraction of Old World leaf beetles in the genusAulacophora to kairomones and parakairomones which are effective lures for New WorldDiabrotica andAcalymma were investigated. Beetles captured on sticky traps baited with single and multicomponent lures were no different from the control traps for two species ofAulacophora. Yellow colored traps and squash blossoms are attractive toAulacophora beetles which detect sub-microgram quantities of cucurbitacins on silica gel. Leaf feeding behavior and flight activity data are correlated with varietal preference of threeAulacophora species. The common response byDiabrotica andAulacophora to cucurbitacins reinforces the two groups' coevolutionary association with the Cucurbitaceae. The apparent lack of a common response toCucurbita blossom volatiles suggests recent evolutionary pathways are substantially different for these two groups of beetles.
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  • 31
    ISSN: 1423-0445
    Keywords: subsociality ; cleptoparasitism ; mimetism ; odour congruity ; homology ; defensive secretions ; Kalahari desert ; Coleoptera ; Tenebrionidae ; Parastizopus armaticeps ; Eremostibes opacus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Parastizopus armaticeps andEremostibes opacus are two closely related desert tenebrionids which also live in close association, the former having biparental brood care and the latter cleptoparasitising the brood.E. opacus is unable to discriminate between the conspecific and host odour even in the absence of physical contact. Gas chromatographic analysis of headspace volatiles of resting animals showed almost complete qualitative and quantitative odour congruity between them. Comparison of these odour profiles with those of two other tenebrionids sharing the same ecological niche,Gonopus agrestis andHerpiscius sp. (damaralis?) showed that congruity was independent of common foodplant utilisation. It is also independent of common defensive gland secretions. Parallels between resting odour spectra, defensive secretion spectra and systematic status suggest that the origins of congruity lie in odour homology, by means of which the cleptoparasite was able to exploit its host.
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  • 32
    ISSN: 1423-0445
    Keywords: volatile substances ; pygidial secretion ; defence ; communication ; species differences ; Coleoptera ; Gyrinidae ; Gyrinus spp
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Gyrinid beetles are common in freshwater habitats. They have paired pygidial glands with a secretion that contains high molecular weight substances rendering them toxic for predatory fish. In this paper we report on a laboratory study on volatile components released by three different gyrinid species when irritated. The volatile pattern had a clear difference between the different species.Gyrinus substriatus andG. aeratus, both produced 3-methyl-1-butanal and 3-methyl-1-butanol when irritated, but in quite different amounts. The third tested species,G. minutus, did not produce any substances above the detection level. It is suggested that the volatile compounds may be part of the beetles' communication and/or defence system.
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  • 33
    ISSN: 1432-1939
    Keywords: Coleoptera ; Herbivory ; Host selection ; Maternal effect ; Paternal effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The natural host of Ophraella notulata is Iva frutescens (Asteraceae); its close relative feeds on a related plant, Ambrosia artemisiifolia. We reared beetles on both plants, obtained progeny from the four possible crosses (two sexes X two parental hosts), and reared the progeny on both plant species. Survival to the imaginal stage of progeny reared on Iva varied with both maternal and paternal host. Hatchling feeding response to both plants showed a maternal host X paternal host interaction. Consumption of Ambrosia by adult beetles was, counter to expectation, higher for progeny of Iva-reared males than Ambrosia-reared males. Oviposition response, although based on too few data to be definitive, was peculiar: parental host did not affect oviposition on Ambrosia; on Iva daughters of Iva-reared males laid significantly more eggs than did daughters of Ambrosia-reared males, but only if they had been reared on Iva; those reared on Ambrosia displayed the reverse pattern. We discuss the possibility that nongenetic paternal transmission of host plant effects may explain these results, but offer a somewhat uncomfortable hypothesis of selection as a preferable explanation. An important outcome of the experiment is that it provided no evidence of maternal effects of host plant on offspring feeding or oviposition.
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  • 34
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    Journal of population economics 9 (1996), S. 415-428 
    ISSN: 1432-1475
    Keywords: H42 ; J 13 ; O 11 ; Fertility ; growth ; public education and health
    Source: Springer Online Journal Archives 1860-2000
    Topics: Sociology , Economics
    Notes: Abstract This paper considers the implications of the financing of government services to children when fertility decisions are endogenously determined. In particular, it is shown that when the services are financed by taxation, the equilibrium outcome is biased away from the socially preferred result. The bias results in higher fertility rates and lower economic growth rates than the efficient social optimum. This arises because each household internalizes the benefits, but not the costs of the tax-financed services. We consider alternative methods of financing the public provision of services and find that a combination of taxation and vouchers can eliminate the bias in the equilibrium outcome.
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  • 35
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    Journal of population economics 9 (1996), S. 415-428 
    ISSN: 1432-1475
    Keywords: Key words: Fertility ; growth ; public education and health
    Source: Springer Online Journal Archives 1860-2000
    Topics: Sociology , Economics
    Notes: Abstract. This paper considers the implications of the financing of government services to children when fertility decisions are endogenously determined. In particular, it is shown that when the services are financed by taxation, the equilibrium outcome is biased away from the socially preferred result. The bias results in higher fertility rates and lower economic growth rates than the efficient social optimum. This arises because each household internalizes the benefits, but not the costs of the tax-financed services. We consider alternative methods of financing the public provision of services and find that a combination of taxation and vouchers can eliminate the bias in the equilibrium outcome. JEL classification: H42, J13, O11
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  • 36
    ISSN: 1432-072X
    Keywords: Key words Protein phosphorylation ; ATP-Pi exchange ; Light-harvesting complexes ; Reaction center ; Photosynthesis ; Photomorphogenesis ; Membrane ; growth ; Polypeptide insertion ; Phospho-amino esters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Membranes of Rhodobacter capsulatus strain U43 (pTX35) showed qualitatively very similar phosphorylation patterns under in vitro and in vivo conditions. In vitro, it was irrelevant whether the phosphate source was orthophosphate or ATP. Inhibitors of electron transport did not inhibit light-harvesting complex I (LHIα) (B870) polypeptide phosphorylation, except for o-phenanthroline, which was strongly inhibitory. Redox conditions regulated the amount of protein phosphorylated; external redox potentials between +200 and +300 mV promoted the reaction. Phosphorylation was inhibited by uncouplers such as carbonyl cyanide m-chlorophenyl hydrazone and nigericin plus valinomycin plus potassium ions. Inhibitors of the H+-ATPase were also inhibitory when the phosphate source was [32P]Pi or [γ-32P]ATP. From these results, it was concluded that an operative reaction center, a coupled membrane, and external redox potentials higher than +200 mV are required for optimum LHIα phosphorylation. We also demonstrated that phosphorylation of LHIα polypeptide occurs before insertion into the membrane and that phosphate is preferentially incorporated into specific domains within the cytoplasmic membrane. Intracytoplasmic membranes, identified here as light membranes, were found to contain a dephosphorylated LHIα polypeptide.
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  • 37
    ISSN: 1440-1703
    Keywords: aquatic macrophyte ; biomass ; growth ; leaf life span ; shoot density ; spatial distribution ; Zizania latifolia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The population and production ecology of aZizania latifolia stand at a sheltered shore of the Hitachi-Tone River were investigated. Shoot emergence was observed twice a year; the fist was a synchronized shoot emergence in April and the second was from August to October. Aboveground biomass was mostly occupied by leaves and peaked at 1500 g dry weight m−2 in August. The belowground biomass also reached its peak, 750 g dry weight m−2, in August. The secondary shoots were small in spite of their high density. Leaves were produced continuously throughout the season. The leaf life span was as short as 55.6 days for cohorts that emerged from May through to September. Total annual net production ofZ. latifolia could be more than 3400 g dry weight m−2. Shoot clusters of several centimeters were observed in April. The following self-thinning caused a regular distribution of the remaining shoots in August. Most shoots produced in August to October were found near a shoot persisting since April. They showed more concentrated distribution than shoots in April. A large biomass allocation to leaves and the ability to produce many clump shoots during the late growing period may facilitate dominance ofZ. latifolia in relatively sheltered sites.
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  • 38
    ISSN: 1573-4919
    Keywords: heart ; postnatal development ; sarcoplasmic reticulum ; phospholamban ; calcium transport ; spontaneously hypertensive rats ; growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract This comparative study investigates the relationship between sarcoplasmic reticulum (SR) calcium(Ca2+)-ATPase transport activity and phospholamban (PLB) phosphorylation in whole cardiac homogenates of spo`ntaneously hypertensive rats (SHR) and their parent, normotensive Wistar Kyoto (WKY) strain during early postnatal development at days 1, 3, 6, 12 and at day 40 to ascertain any difference in SR Ca2+ handling before the onset of hypertension. At day 1, the rate of homogenate oxalate-supported Ca2+ uptake was significantly higher in SHR than in WKY (0.25 ± 0.02 vs 0.12 ± 0.01 nmoles Ca2+/mg wet ventricular weight/min, respectively; p 〈 0.001). This interstrain difference disappeared with further developmental increase in SR Ca2+ transport. Western Blot analysis and a semiquantitative ELISA did not reveal any difference in the amount of immunoreactive PLB (per mg of total tissue protein) between strains at any of the ages studied. In addition, levels of phosphorylated PLB formed in vitro in the presence of radiolabelled ATP and catalytic (C) subunit of protein kinase A did not differ between SHR and WKY at days 1, 3, 6 and 12. At day 40, C subunit-catalyzed formation of 32P-PLB was reduced by 66% (p 〈 0.001) in SHR when compared to age-matched WKY In the early postnatal period between day 1 and 12 SR Ca2+-transport values were linearly related to the respective 32P-PLB levels of both SHR and WKY rats. The results indicate that cardiac SR of SHR can sequester Ca2+ at a much higher rate immediately after birth compared to WKY rats. The disappearance of this interstrain difference with further development suggests that some endogenous neuroendocrine or nutritional factor(s) from the hypertensive mother may exert an influence upon the developing heart in utero resulting in a transiently advanced maturation of the SR Ca2+ transport function in SHR pups at the time of birth.
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  • 39
    ISSN: 1573-1561
    Keywords: Encelia farinosa ; Asteraceae ; Trirhabda geminata ; Coleoptera ; Chrysomelidae ; feeding preferences ; acidic deposition ; plant stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Container grownEncelia farinosa were exposed to three 3-hr episodes of acidic fog (pH 2.5) typical of events in southern California. Adults and larvae of the specialist leaf-feeding herbivore,Trirhabda geminata, preferred to feed on the acidic-treated foliage compared to control fogged (pH 6.3–6.5) foliage. Previous feeding damage on the plants did not affect feeding preference. The acidic-fogged foliage was significantly higher in total nitrogen and soluble protein but not different from control-treated tissue in water content. Stress on native populations of this drought-deciduous shrub caused by atmospheric pollutants may also result in altered feeding ecology of the beetle.
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  • 40
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    Journal of chemical ecology 19 (1993), S. 395-410 
    ISSN: 1573-1561
    Keywords: Oreina gloriosa ; Coleoptera ; Chrysomelidae ; chemical defense ; cardenolides ; quantitative variation ; aging ; HPLC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The defensive secretion of the alpine chrysomelidOreina gloriosa is a complex mixture of mainly cardenolides and tyrosine betaine. Individually sampled secretions of adult laboratory-reared and field-collected beetles were analyzed by reverse-phase HPLC; 16 secretion components were quantified. Quantities and concentrations of different components were significantly affected by the age, sex, and reproductive status of individual beetles. Aging was correlated with marked increases (up to 4.4-fold) and decreases (up to 2.7-fold) of quantities and concentrations of several components. Differences between the sexes were smaller, but quantities of all components and concentrations of several components were larger in laboratory-reared females than in males. There was less of one component of the secretion in mated than unmated females, but the concentrations of four secretion components were higher (up to 1.6-fold) in mated females.
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  • 41
    ISSN: 1573-1561
    Keywords: Rapeseed ; Brassica spp. ; allyl isothiocyanate ; glucosinolates ; allelochemicals ; Limonius californicus (Mann.) ; Coleoptera ; Elateridae ; toxicity ; sublethal effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Acute toxicity of soil amended with allyl isothiocyanate (AITC) to three size classes ofLimonius californicus (Mann.) wireworms was determined in the laboratory. Wireworms were exposed to AITC at initial concentrations of 120–300 nmol/g soil for one day. During this time, extractable AITC concentrations decreased by 66 to 93 %. Probit analysis estimated LC50 values of 238 and 226 nmol/g soil at one day posttreatment for medium and large wireworms, respectively. For small wireworms, LC50 values decreased from 211 to 157 nmol/g soil during 1–137 days posttreatment. Sublethal concentrations of AITC significantly reduced feeding activity of treated wireworms at three posttreatment times and over the entire 137 days. Wireworm weight was not significantly affected by AITC. The potential exists to use glucosinolate-containing plant tissue as an isothiocyanate (ITC) source to reduce crop damage caused byL. californicus wireworms.
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  • 42
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    Journal of chemical ecology 19 (1993), S. 1219-1231 
    ISSN: 1573-1561
    Keywords: Host recognition behavior ; entomopathogenic nematodes ; feces ; Spodoptera exigua ; Lepidoptera ; Noctuidae ; Popillia japonica ; Coleoptera ; Scarabaeidae ; Blattella germanica ; Blatteria ; BlattellidaeAcheata domesticus ; Orthoptera ; Gryllidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Host recognition by entomopathogenic nematodes may occur through contact with insects' excretory products, cuticle, or gut contents. We analyzed the behavioral responses of four species of entomopathogenic nematodes during contact with feces of natural or experimental hosts. Host recognition by nematodes was manifested in alterations in the frequency and/or duration of one or more search parameters including forward crawling, headwaving, body-waving, stopping, backward crawling, head-rubbing, and headthrusting.Heterorhabditis bacteriophora andSteinernema glaseri showed behavioral responses to contact with feces of their natural hosts,Spodoptera exigua (Lepidoptera) andPopillia japonica (Coleoptera), and to the experimental hosts,Acheata domesticus (Orthoptera) andBlatella germanica (Blatteria).Steinernema carpocapsae responded only toB. germanica feces, whereas5. scapterisci did not significantly respond to any of the insect species. During contact with cockroach feces, all nematodes, exceptS. scapterisci, showed avoidance behavior. We suggest that ammonia present in cockroach feces is inhibitory to nematodes. Specific host recognition by entomopathogenic nematodes may be an important mechanism to maintain host affinities.
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  • 43
    ISSN: 1573-1561
    Keywords: Holotrichia parallela ; large black chafer ; scarab beetle ; Coleoptera ; Scarabaeidae ; isoleucine methyl ester ; linalool ; sex pheromone ; circabidian periodicity ; pheromone titer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract (R)-(−)-Linalool was identified as a minor component sex pheromone of the scarab beetleHolotrichia parallela (Coleoptera: Scarabaeidae). Field evaluations revealed that, although not attractive per se, (R)-(−)-linalool enhances the attractiveness of the major sex pheromone,L-isoleucine methyl ester (LIME). Analyses of the pheromone titers in the glands of field-collected females demonstrated the occurrence of peak levels of 48-hr (“circabidian”) periodicity. The levels of LIME in the glands of 45-day-old virgin females increased over three times from the scototo the photophase of a calling day, but the amounts of (R)-(−)-linalool did not significantly change. Virgin females had in average two times more LIME and 3.6 times more (R)-(−)-linalool than the average amount found in the field-captured beetles throughout the season.
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  • 44
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    Journal of chemical ecology 19 (1993), S. 1453-1459 
    ISSN: 1573-1561
    Keywords: Anomala schonfeldti ; Popillia japonica ; scarab beetle ; Coleoptera ; Scarabaeidae ; 2-(E)-nonenol ; sex pheromone ; mark-and-recapture ; field test ; mass trapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Synthetic 2-(E)-nonenol, previously identified as the sex pheromone ofAnomala schonfeldti (Coleoptera: Scarabaeidae), is demonstrated to be very attractive to males in the field. Nevertheless, no significant differences were found between treatments with 1, 5, 10, and 20 mg dosages. Males ofA. schonfeldti were more significantly attracted to traps at 30 cm high than at 90 cm. Although the observed behavior seemed to indicate a trend of more attraction to buried traps than those placed at 30 cm, there was no statistical difference between the two treatments. Pheromone-baited traps caught significantly more beetles than traps containing three virgin females. Over 70% of released beetles were recaptured in six traps surrounding the point of release and separated from each other by 50 m, suggesting a possible use of the pheromone (in combination with floral compounds) in mass trapping.
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  • 45
    ISSN: 1573-1561
    Keywords: Sitophilus granarius ; grain weevil ; Coleoptera ; aggregation pheromone ; electroantennogram ; coupled GC-EAG ; behavioral bioassay ; circular dichroism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Coupled GC-EAG techniques have been applied to the study of volatiles from the grain weevil,Sitophilus granarius. for the first time. The size of EAG response was independent of the sex of the responding insect but was consistently larger to extracts of males than those of females. This difference was reflected in a behavioral preference for the male extracts by mated adults of both sexes tested together and virgin adults of both sexes tested separately. The GC-EAG results provide evidence for two materials that are released specifically by the males. Using circular dichroism. one has been found to be identical stereochemically with the (2S,3R)-sitophilate reported by others as the aggregation pheromone in a different strain. This enhances the prospects for the development of a single pheromone lure that would be generally applicable whatever the origin of the strain. The small amount of sitophilate found in the males suggests that it is not stored in large amounts. The other material, present in such a small amount that it has yet to be fully characterized, elicits a higher antennal activity than sitophilate and may have a significant role to play in enhancing the trap catch of this economically important pest.
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  • 46
    ISSN: 1573-1561
    Keywords: Coleoptera ; Staphylinidae ; Tenebrionidae ; larvae ; defensive glands ; quinone ; naphthoquinone ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The abdominal glands of three bark-inhabiting larvae of generaBolitochara, Leptusa (Staphylinidae), andHypophloeus (Tenebrionidae) were studied chemically and morphologically. Behavior of the larvae indicated that secretion is emitted only after severe disturbance of the larvae. These mechanical contacts may also occur incidentally with coinhabiting nonpredatory arthropods when the beetle larvae move within small interstices under bark. Depending on the species, the secretions contained 1,4-benzoquinone derivatives and three 6-alkyl-naphthoquinones dissolved within various alkanes, alkenes, ethyl-, isopropyl-, and isoamylesters. More erratically distributed gland constituents also detected were acetophenone, benzyl propionate, and methyl hydroxybenzoate. In the laboratory, synthetic quinone-containing solutions simulating those found inLeptusa andBolitochara larvae acted as strong topical irritants and caused further damage to last-stageCalliphora vomitoria larvae if hydrocarbons or esters were used as solvents. The natural secretions ofHypophloeus versipellis elicited considerable mortality in two subcortical sciarid larvae cooccurring with tenebrionid larvae. Bioassay and secretion chemistry of the Staphylinidae/Tenebrionidae larval secretions indicated that they are typical defensive secretions that act topically. Morphological data characterized Bolitocharini larvae as possessing protuberant abdominal tergites supplied with an interiorly situated gland reservoir. After mechanical contact, the defensive secretion is topically applied to other arthropods by dabbing this tergal protuberance on targets. The defensive gland ofHypophloeus versipellis is unusual in possessing a movable reservoir opening situated at the anterior border of tergite IX. By this peculiar gland morphologyHypophloeus larvae are capable of shooting secretion droplets frontally from their slightly depressed dorsal abdominal surface without bending their abdominal tips dorsally. This seems an adaptation to the interstitial habitat of the larvae. The types of defensive glands and their phylogenetic value in Aleocharinae/Tenebrionidae larvae are discussed.
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  • 47
    ISSN: 1573-1561
    Keywords: Hylastes cunicularius ; Hylastes brunneus ; Hylastes opacus ; Dryocoetes autographus ; Hylobius abietis ; Hylobius pinastri ; α-pinene ; terpenes ; turpentine ; ethanol ; ground traps ; Coleoptera ; Scolytidae ; Curculionidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Responses of threeHylastes species,Dryocoetes autographus, and twoHylobius species to terpenes and ethanol were studied in field experiments on clear-cut forest sites in Sweden using baited ground traps.α-Pinene alone did not attract any of the six species. A terpene blend (spruce turpentine consisting mainly ofα-pinene,β-pinene, and 3-carene) attractedHylastes cunicularius, H. brunneus, andHylobius abietis in some experiments, but not in others. The attractiveness of ethanol also varied; the only species consistently attracted wasH. abietis. Baits containing both terpenes and ethanol, particularly the combination of spruce turpentine and ethanol, were attractive to all species exceptHylobius pinastri. InH. abietis, the terpene plus ethanol/ ethanol catch ratios increased during early summer. Seasonal differences in catch levels were observed inH. cunicularius andH. abietis. The addition ofα-pinene reduced the attractiveness of the combination of spruce turpentine and ethanol toH. cunicularius, H. opacus, andD. autographus. The differences in response to the volatiles between species are probably related to differences in reproductive behavior and host preferences.
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  • 48
    ISSN: 1432-0878
    Keywords: Key words: Aesthetasc ; Chemoreception ; Dendrite Blue crab ; growth ; Olfaction ; Salinity adaptation ; Sensilla ; Callinectes sapidus (Crustacea)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The aesthetasc sensilla of the euryhaline blue crab, Callinectes sapidus, are innervated by the dendrites of from 40 to 160 bipolar chemosensory neurons. Each dendrite forms two cilia within the basal portion of the sensillum, and these subsequently branch yielding approximately 10 outer dendritic segments per neuron. Auxiliary cells surround the inner dendritic segments and also ensheathe the outer dendritic segments up to the terminus of the ”constricted region” (a zone in which there is a slight narrowing of the aesthetasc). Crystal violet staining suggesting access of odor stimuli is limited to that portion of the sensillum distal to the constricted region. In freshwater-acclimated blue crabs the length and level of branching in the dendrites extending beyond the constricted region is significantly reduced relative to that of seawater-acclimated animals (mean lengths: 150 µm versus 517 µm, respectively). After transfer of freshwater-acclimated crabs to seawater there is a rapid increase in length of the outer dendritic segments, reaching 60% of that for seawater-acclimated crabs by 48 h. A similar time course for regrowth is seen for seawater-acclimated crabs in which the outer dendritic segments have been osmotically ablated. Conversely, with rapid transfer of seawater-acclimated animals to lower salinities, there is a correspondingly rapid reduction in length of the outer dendritic segments. The reduced length of the outer dendritic segments in freshwater-acclimated animals may reflect the effective distance over which an appropriate osmotic/ionic microenvironment for neural function can be maintained within the aesthetasc.
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  • 49
    ISSN: 1871-4528
    Keywords: Solanum tuberosum L. ; temperature stress ; growth ; nutrient deficiency ; tuber analysis ; tuber size ; glasshouse ; growth room
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary To determine calcium fertility and high temperature effects on internal brown spot development in potato, cv. Russet Burbank plants were fertilised with Hoagland's nutrient solution with or without calcium. Prevalence and severity of internal brown spot were greatest in tubers receiving no calcium fertilisation during growth. Internal brown spot was evident as early as tuber initiation. A high growth medium temperature (32°C) at tuber maturity with a lack of calcium increased internal brown spot incidence and severity. No tubers subjected to the high temperature and fertilised with calcium developed internal brown spot. Peel calcium concentration of tubers receiving no calcium fertilisation was lower (0.5–0.8 g/kg) than tubers receiving calcium (1.2–1.9 g/kg). Medullary tissue calcium concentration was similar under both calcium regimes. Calcium availability during early tuber growth was an influential factor in internal brown spot development, however high temperature effects may not be discounted in exacerbating the disorder.
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  • 50
    ISSN: 1573-5176
    Keywords: integrated culture ; kelp ; salmon ; growth ; economics ; nutrient uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The technical and economical feasibility of farmingLaminaria saccharina for a food base product near a salmon sea cage farm was evaluated. Suitability of kelp for nutrient removal was also analyzed. A computer model of a conceptualized system was developed in order to make the assessments. Kelp growth was modelled as a linear function of temperature and background dissolved inorganic nitrogen concentration, and it was partially experimentally validated. Based on model simulations, aLaminaria farm containing 10,60 m ropes on each end of a salmon sea cage farm is fertilized by the salmon farm and yields annually 1600 kg of dried kelp. The payback period for the initial investment of $61 × 103 is 6 years after which an annual net profit of 20 × 103 Canadian dollars ($16.68 × 103 US) can be achieved. The net present worth of the kelp farm was positive for a rate of return up to 25%. Kelp production on multiple salmon farms or at a higher kelp density could increase the overall revenue. The kelp farm does not appreciably affect background nutrient or oxygen levels. With a few modifications in the model,Nereocystis andMacrocystis farming can be substituted and evaluated for feasibility and nutrient removal efficiency.
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  • 51
    ISSN: 1573-5176
    Keywords: Haematococcus pluvialis ; ethylene ; growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the freshwater ChlorophyceaeHaematococcus pluvialis, precursors of ethylene biosynthesis cycle are the same as those of higher plants: L-methionine → S-adenosylmethionine → 1-aminocyclopropane-1-carboxylic acid → ethylene. However, the enzymatic complex of the last step of ethylene synthesis-ACCoxidase-differs from that of higher plants. It is stimulated by Co2+ (at least 10-5 M), Mn2+ (at least 10-6 M) and Ag2+ (at least 10-4 M), inhibited by Cu2+ (at least 10-5 M) and not affected by Zn2+, Fe2+ or Mg2+. ACCoxidase is also inhibited by salicylhydroxamic acid and by dark. Ethylene production is more important in young, mobile, green cells in active growth phase than in old, encysted and red cells in stationary growth phase. No peaks in ethylene production or respiration were observed during batch culture, as opposed to the situation with climacteric fruits.
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  • 52
    ISSN: 1573-5176
    Keywords: Gracilaria chilensis ; growth ; nutrient pulses ; epiphyte abundance
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    Topics: Biology
    Notes: Abstract The effect of nutrient pulse concentration and frequency onGracilaria chilensis Bird, McLachlanet O Oliveira growth and epiphyte abundace was investigated for plants grown in an indoor culture facility. The frequency of nutrient pulses (which ranged from 1 pulse to 4 pulses per 14 days) had a strong influence on plant growth, while pulse concentration (from 72 to 143 µM as ammonium) had a lesser influence. Growth became a function of total N flux only when plants received nutrient pulses at least twice per 14 days. Both pulse frequency and pulse concentration affected the abundance of epiphytic algae found attached toGracilaria thalli, but pulse frequency was the more significant of the two factors. Their effects could be combined into the single factor, total N flux. Both reasonableG. chilensis growth and low levels of epiphytes were achieved under these conditions (20 °C, 25 µ mol photon m−2 s−1 PAR) if ammonium was pulsed at relatively high concentrations (up to 150 µM) once every 7 days into otherwise nitrogen-depleted seawater.
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  • 53
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    Journal of applied phycology 5 (1993), S. 547-549 
    ISSN: 1573-5176
    Keywords: Trentepohlia odorata ; Dunaliella bardawil ; light intensity ; nitrogen ; growth ; carotenogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract AxenicTrentepohlia odorata was cultured at three different NH4Cl levels (3.5 × 10−2, 3.5 × 10−3, 3.5 × 10−4 M) and three different light intensities (48, 76, 122 µmol m−2 s−1). Chloride had no effect on growth over this range of concentration. High light intensity and high NH4Cl concentration enhanced the specific growth rate. The carotenoid content increased under a combination of high light intensity and low N concentration. WhenD. bardawil was exposed to the same combination of growth conditions, there was an increase in its carotenoid content. The light saturation and the light inhibition constants (K s andK i, respectively) for growth, and the saturation constant (K m) for NH4Cl were determined. TheK s andK i values were higher inT. odorata (66.7 and〉 122 σmol m−2 s−1, respectively) than inD. bardawil (5.1 and 14.7 µmol m−2 s−1, respectively). TheK m value determined at 122 µmol m−2 s−1, however, was lower inT. odorata (0.048 µM) than inD. bardawil (0.062 µM).
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  • 54
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    Journal of applied phycology 5 (1993), S. 563-571 
    ISSN: 1573-5176
    Keywords: CO2 ; Gracilaria ; growth ; nitrate ; 18O2 ; photorespiration ; photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The influence of elevated CO2 concentrations on growth and photosynthesis ofGracilaria sp. andG. chilensis was investigated in order to procure information on the effective utilization of CO2. Growth of both was enhanced by CO2 enrichment (air + 650 ppm CO2, air + 1250 ppm CO2, the enhancement being greater inGracilaria sp. Both species increased uptake of NO3 − with CO2 enrichment. Photosynthetic inorganic carbon uptake was depressed inG. chilensis by pre-culture (15 days) with CO2 enrichment, but little affected inGracilaria sp. Mass spectrometric analysis showed that O2 uptake was higher in the light than in the dark for both species and in both cases was higher inGracilaria sp. The higher growth enhancement inGracilaria sp. was attributed to greater depression of photorespiration by the enrichment of CO2 in culture.
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  • 55
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    Journal of applied phycology 8 (1996), S. 421-430 
    ISSN: 1573-5176
    Keywords: Gracilaria gracilis ; suspended cultivation ; vegetative propagation ; South Africa ; yield ; growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rope rafts were used to evaluate the growth of localGracilaria gracilis at Saldanha Bay, on the west coast of South Africa, over four years. The plants were grown on horizontally-suspended ropes or netting lines. Relative Growth Rates (RGR) of plants on ropes with low stocking weights often exceeded 10% d−1 in (austral) summer, and fell to between 6 and 7.5% d−1 in winter. Commercial-style lines of plastic netting stocked at 400 g m−1 and placed 0.75 m apart yielded a mean of about 2 kg m−2 30 d−1, with a mean RGR of about 5% d−1 over a two-year period. Various methods of improving yields were tested, including attaching floats to individual lines and optimising stocking weight. In Saldanha Bay in late summer, warm, oligotrophic water can severely reduce growth. Growth was optimised by growing the plants as close as possible to the surface (0.2 m), where water motion, and by implication, nutrient uptake, are higher. Agar content and gel strength generally remained high all year round. The potential for commercial production is evaluated in the light of these results.
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  • 56
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    International journal of anthropology 8 (1993), S. 1-9 
    ISSN: 1824-3096
    Keywords: growth ; anthropometric characteristics ; sexual dimorphism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A mixed longitudinal study of growth and development has been conducted, centering on an analysis of differences based on sex between the ages of 8 and 18 years for a series of 12 anthropometric indicators. The sample consisted of 50 girls and 63 boys. Proceeding from the specific differences, the variables can be divided into four groups with identical structures of differences. The first group comprises measurements of body height, body mass, shoulder width and pelvic span, all of which have higher values in boys between 8 and 10 and between 14 and 18. Between the ages of 11 and 13 girls are taller, heavier, with broader shoulders and pelvises. The second group covers measurements of subcutaneous fat. which are higher for girls throughout the period under review. The third group of indicators comprises the diameters of the joints of the extremities, i.e. of elbows and knees. Throughout the period under observation, these measurements are higher in boys, with the absolute differences between the sexes being the same at the age of 8 and ten years later. The fourth group consists of circumferences measurements of the extremities. It was found that calf circumferences manifested a specific inversion of the curves between 14 and 15, with girls showing a larger calf circumference up to the age of 14, and boys from the age of 15. The effect of earlier onset of puberty in girls was found to be reflected only on the inversion of the curve flow of the variables from the first group.
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  • 57
    ISSN: 1573-5176
    Keywords: nitrate uptake ; growth ; immobilized cells ; alginate bead ; Chlorella vulgaris
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Growth and nitrate uptake were studied on free-living and immobilizedChlorella vulgaris cells cultivated in medium containing different nitrate concentrations. First, the effect of nitrate concentrations on growth indicated that cells can live in the presence of high concentrations as high as 97 mM. Although no lethal effect on cells was observed such concentration a slow down in growth and a decrease in biomass produced was observed. The rate of nitrate uptake increased with the nitrate concentration in the medium. The maximum uptake rate was reached in first days of culture in both free-living and immobilized cells. The rate dropped more rapidly for cells growing in 2 mM nitrate than for cells growing in higher nitrate concentration. The maximum rate was very much the same for free-living and immobilized and was within the order of 0.45 to 0.57 μg NO3 h−1 10−6 cells. Immobilization modified the changes of nitrate uptake rate for concentration higher than 2 mM.
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  • 58
    ISSN: 1573-5176
    Keywords: Rhodophyceae ; Calliblepharis jubata ; growth ; carrageenan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Study of the seasonal variation in the quality and content of iota carrageenan inCalliblepharis jubata from the Normandy coast of France shows that seasonal fluctuation of the environment affects the growth and chemical composition of this red alga. Growth increases during winter, when there is little synthesis of carrageenan and floridean starch is accumulated. When inorganic nitrogen content decreases, growth also decreases and stops (May to August); with high light intensity, the metabolism is oriented towards a synthesis of parietal carrageenans to the detriment of the reserve products such as floridean starch.
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  • 59
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    Journal of applied phycology 8 (1996), S. 87-103 
    ISSN: 1573-5176
    Keywords: Ascophyllum nodosum ; growth ; harvesting effects ; reproduction ; season ; survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Although populations ofAscophyllum nodosum are harvested commercially, little is known about the effects on demographic vital rates (growth, reproduction, survival). This study examines the effects of harvesting season and harvesting intensity on growth, reproduction and mortality of intact fronds in four size classes and in fronds truncated by the harvest. Knowledge of size-specific vital rates was used to evaluate the response of the population to harvesting. Harvesting season and harvesting intensity did not exert a significant effect on growth. Growth in plots not subject to harvesting was less than in harvested plots. No major differences in growth, reproduction and survival between intact and severed fronds emerged. The number of fronds attaining reproduction was enhanced by increased harvesting intensity and by cutting in summer. Harvesting did not seem to induce breakage, and breakage appeared higher in the uncut plots. Most harvesting treatments did not influence survivorship and survivorship was similar among all size classes. Growth rates were inversely related to sizes of fronds. Assessment of variation across size classes yielded more accurate estimates of growth rates than those of previously used methods. Accurate size class specific-growth rates will be a useful criterion when regulating intervals between harvests. Furthermore, assessment of size-specific vital rates allows identification of the frond size classes most relevant to the preservation of resources. Because of their fast growth rates and abundance, fronds in class 1, and, to a lesser extent, class 2, are responsible for most of the population regrowth after harvest. In contrast, classes 3 and 4 contribute little to recovery. This finding provides a strong basis for a harvesting strategy that targets the largest fronds.
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  • 60
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    Cytotechnology 20 (1996), S. 13-22 
    ISSN: 1573-0778
    Keywords: insect tissue culture ; cell-specific lines ; survival ; growth ; cell differentiation ; applications
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Conclusion Current methods of insect cell culture have produced a limited variety of cell types in an ever expanding list of insect cell lines. In developing midgut epithelial cell lines, we found that traditional methods in insect cell culture failed to provide healthy cells from mature tissues. Examination of mammalian cell culture literature for this particular cell type provided the insight required to successfully develop a cell-specific line (Baines et al., 1994). The potential applications for cell-specific lines from insects are numerous. This paper is a compilation of ideas that will hopefully enable other researchers to develop additional cell-specific lines.
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  • 61
    ISSN: 1572-9710
    Keywords: saproxylic ; Coleoptera ; spruce forest ; spatial scale ; conservation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: The diversity in different groups of obligate saproxylic beetles was related to ecological variables at three levels of spatial scale in mature spruce-dominated forest. The variables were connected to: (i) decaying wood, (ii) wood-inhabiting fungi, (iii) the level of disturbance, (iv) landscape ecology, and (v) vegetational structure. Several strong relationships were found at medium (1 km2) and large scales (4 km2), while only weak relationships were found at a small scale (0.16 ha; 1 ha=104 m2). This may be explained by the local variations in habitat parameters and the high mobilities of many beetle species. Factors connected to decaying wood and wood-inhabiting fungi were clearly the most important factors at all scale levels. In particular, the variables diversity of dead tree parts, number of dead trees of large diameter and number of polypore fungi species increased the species richness of many groups and increased the abundance of many species. Eight species were absent below a certain density of decaying wood per 1 or 4 km2. Former extensive cutting was a negative factor at large scale, probably because of decreasing recolonization with increasing distance to the source habitats. Thinning reduced the diversity of species associated with birch. The development of guidelines favouring the diversity of saproxylic beetles are discussed below.
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  • 62
    ISSN: 1573-8477
    Keywords: amphibian ; body size ; clonal ; genetic compatibility ; growth ; hybridogenesis ; local adaptation ; metamorphosis ; Rana esculenta ; tadpole
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Hybridogenetic species possess a hybrid genome: half is clonally inherited (hemiclonal reproduction) while the other half is obtained each generation by sexual reproduction with a parental species. We addressed the question of whether different hemiclones of the hybridogenetic water frogRana esculenta are locally adapted for genetic compatibility with their sexual parental hostRana lessonae. We artificially crossedR. esculenta females of three hemiclones (GUT1, GUT2 and GUT3) from a pond near Gütighausen, Switzerland and one hemiclone (HEL1) from near Hellberg, Switzerland each toR. lessonae males from both populations. We also created primary hybrids by crossing the sameR. lessonae males from both populations toR. ridibunda females from Poznań, Poland (POZ). Tadpoles were then reared in the laboratory at two food levels to assess their performance related to early larval growth rate, body size at metamorphosis and length of the larval period. Tadpoles from hemiclones GUT1, GUT3 and POZ had higher growth rates than those from hemiclones GUT2 and HEL1 at the low food level, but at the high food level all growth rates were higher and diverged significantly between hemiclones GUT2 and HEL1. Tadpoles from the intrapopulational crosses GUT2 × GUT and HEL1 × HEL were larger at metamorphosis than those from the interpopulational crosses GUT2 × HEL and HEL1 × GUT. A high food level increased the size at metamorphosis in all tadpoles. A high food level also decreased the days to metamorphosis and tadpoles from GUT1, GUT3 and POZ had the shortest larval period whereas those from GUT2 and HEL1 had the longest. These results indicate that the differential compatibility of clonal genomes may play an important role in hybridogenetic species successfully using locally adapted sexual genomes of parental species and that interclonal selection is likely important in determining the distribution of hemiclones among local populations.
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  • 63
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    Hydrobiologia 319 (1996), S. 15-21 
    ISSN: 1573-5117
    Keywords: brachyuran crab ; fecundity ; growth ; Metopograpsus messor ; reproduction ; seasonal changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The annual cycle of a Metopograpsus population (Muzhupilangad estuary) had three distinct periods: (1) growth-reproduction (January–May), when crabs were involved in moult and reproduction; (2) inactive period (June–July), and (3) reproductive period (August–December). Usually, spawning was immediately followed by another vitellogenic cycle, paralleled by the embryogenesis of prehatch eggs in the brood. Moulting was seemingly an annual event. In the programming of moult and reproduction, the species deviated from the common brachyuran pattern, inasmuch as the postmoult females engaged in active vitellogenesis. The synchrony in the stages of maturation and spawning, and the precision with which the physiological events are programmed, make this highly fecund species an ideal model for an integrated study of the physiology of growth and reproduction.
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  • 64
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    Hydrobiologia 325 (1996), S. 39-46 
    ISSN: 1573-5117
    Keywords: roach ; pike ; chub ; growth ; river zones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Variation in the growth patterns of roach, Rutilus rutilus (L.), pike, Esox lucius L., and chub, Leuciscus cephalus (L.) was examined along the upper Warta River, where human impact (mostly pollution) has influenced the longitudinal zonation on the fish assemblage. Significant differences were found in the exponent of weight-length relationships for roach and chub populations occupying different zones of the river, but no such variation was observed in pike. Moreover, pike growth was isometric, whereas roach and chub grew allometrically, with regression coefficients (slope) above 3. Although the length-at-age data were similar for each zone, the von Bertalanffy parameters (L inf, K and t 0) suggest that there may exist some inter-zone variation in the overall growth patterns of these species. All the species grew better in the zone where the index of relative abundance (relating dominance of a particular species to its maximum abundance in river system) achieved its highest value. The results suggest that a relative abundance index expressed in this way can be a good index of ‘habitat quality’.
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  • 65
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    Hydrobiologia 338 (1996), S. 163-172 
    ISSN: 1573-5117
    Keywords: lake smelt ; vendace ; bream ; pikeperch ; spawning ; fecundity ; feeding ; growth ; fisheries management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lake Peipsi is a large (3558 km2) and relatively shallow (up to 15.3 m) productive smelt-bream-pikeperch lake on the territories of Estonia and Russia. 34 fish and lamprey species inhabit this lake permanently, the main commercial fishes being smelt, perch, ruffe, roach, bream, pike, up to the 1990s also vendace and lately pikeperch. The second-rate commercial fishes are burbot, whitefish, white bream and bleak. In general, the spawning and feeding conditions of fishes are more or less favourable in the lake. Bream and pike grow fast, the majority of the other investigated fish species passably. The total catch of fish has usually been 9000–12000 t (25–34 kg ha−1) a year. As a result of the intensive use of trawls and fine-meshed Danish seines, the stock of pikeperch was strongly suppressed for a long time. After trawls were prohibited and the number of Danish seines considerably restricted, the stock and catches of pikeperch began to grow rapidly; pikeperch has become one of the main commercial fishes in the lake. During the last years the abundance of vendace has sharply decreased, and it has lost (we hope, temporarily) its economic importance. This is probably caused, first of all, by the high mortality of its eggs on the spawning grounds during successive mild winters of the last years. An increasing pressure from pikeperch (a big predator) has also contributed to strong decline of the stock of vendace. It would be reasonable to begin a regular introduction of elvers into the lake.
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  • 66
    ISSN: 1573-5117
    Keywords: Phragmites australis ; reed decline ; growth ; biomass allocation ; nutrient uptake ; eutrophication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Performance of young Phragmites australis plants was examined after 7 weeks on an artificial nutrient-enriched inorganic substrate and on the same substrate to which an organic sediment from a eutrophic lake was added, at three different water depth treatments. Growth decreased, and proportional allocation of biomass to roots increased, with the addition of sediment. These differences were significant in shallow and deep water, but not at a medium depth. Concentrations of phosphorus and nitrogen in plant biomass decreased, and concentration of iron increased, with addition of sediment. The effects of sediment addition may have resulted from a decreased availability of nutrients in the substrate or from an impaired root functioning. Nutrient exhaustion in the substrate, due to a fast plant growth, can explain the relatively strong effects in shallow water. Deep water, on the other hand, probably restricted oxygen transport to the roots, resulting in an impaired root functioning in the low-redox sediment environment. The results show that, especially in relatively deep water, growth of undisturbed plants of P. australis may be inhibited by eutrophication of sediments, probably because of an impaired root functioning in sediments containing reduced toxic compounds (e.g. ferrous iron).
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  • 67
    ISSN: 1573-5117
    Keywords: Chironomus tentans ; growth ; emergence ; sediment toxicity assessment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A laboratory study was conducted with Chironomus tentans to assess the significance of growth retardation of third-to fourth-instar larvae over a 10-d test period on long-term survival, adult emergence, and ovipositing success. Data were intended to provide interpretive guidance for the commonly used growth endpoint in 10-d sediment bioassays with C. tentans. Larval growth was controlled by using six feeding levels ranging from 0.2 to 5.9 mg dry weight Tetrafin® fish food per day. Mean 10-d survival was ≥88% at all feeding levels, but larval growth decreased significantly (p〈0.05) with each decrease in feeding level. Cumulative successful emergence of adult C. tentans decreased significantly with decreasing larval growth. Mean times to emergence always increased with decreasing growth rates and effects were generally more pronounced for females than males. At the lowest 10-d mean growth where successful emergence occurred (0.27 mg), the times to emergence doubled relative to the times observed at the highest 10-d mean growth (1.03 mg). Ten-day larval growth retardation was strongly correlated with reduction in adult emergence success (r 2 = 0.96). Growth retardations ≥64% resulted in 86–100% reductions in adult emergence. Growth retardation in the range of 35 to 50% equated with comparable percent reductions in adult emergence success. Although fewer females successfully emerged at 10-d growths of 0.37 and 0.74 mg relative to the highest 10-d growth (1.03 mg), ovipositing success of these females did not appear to be adversely affected by either their slower growth rates or their lower mean dry weights (0.62 and 0.99 mg, respectively). Growth of second generation larvae did not appear to be affected by maternal growth rate, but rather appeared to be solely correlated with their own feeding level.
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  • 68
    ISSN: 1573-5117
    Keywords: exploitation rate ; recruitment ; mortality ; growth ; sex ratios
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Monthly length-frequency data of green tiger prawns from April 1985 to August 1990 were analyzed to estimate the von Bertalanffy growth curves and related parameters. The mean asymptotic carapace lengths (L ∞) and growth constants (K) over 5 seasons were 36.6 mm and 1.6 yr−1 for males and 51.2 mm and 1.7 yr−1 for females, respectively. Annual total mortality rates (Z) from 1985/86 to 1989/90 ranged from 2.7 to 6.5 yr−1 for males and from 2.8 to 6.8 yr−1 1 for females. The mean exploitation rates calculated using the mean natural mortality rates (M) of 2.5 yr−1 for males and 2.4 yr−1 for females showed that the male green tiger prawns in Kuwait waters were under exploited, whereas the catch of females was very close to the sustainable yield. Chi-square tests indicated that the sex ratio was close to one for adults (CL ≽ 26 mm), but significantly favoured males for recruits (CL 〈 26 mm). A major recruitment was detected from June/July in all seasons and a minor recruitment in some seasons in August/September. The relative yield-per-recruit (Y'/R) reached the optimum at the length-at-first capture (L c) of 25 mm CL for males, and increased as L c increased for females. The observed mean L c, values were 23.4 mm for both males and females. The Y'/R under the current exploitation level is close to the maximum sustainable yield for females, but lower for males. More fishing effort could be exerted to exploit males, but doing so may not be biologically or commercially possible with current trawling practices.
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  • 69
    ISSN: 1573-5117
    Keywords: Daphnia ; diapause ; growth ; maturity ; clutch size ; intrinsic rate of increase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Laboratory and field investigations revealed that the life history traits of exephippial and parthenogenetic generations of Daphnia differ substantially. Daphniids hatching from resting eggs grow faster and their definitive body sizes are bigger than of hatchlings from subitaneous eggs. Size at maturity for exephippial animals is significantly larger. In spite of this, they mature a few days earlier than parthenogenetic females. In this study, the difference was 3–4 days for the laboratory experiments and 1–3 days for the field. Fecundity of the exephippial generation is markedly higher. Here, the clutch size for this generation was up to 3.5–4.0 times as large as for the parthenogenetic generation. Moreover, obtained results suggest that the relationship between clutch size and body length for both generations differ significantly. Estimates of the intrinsic rate of increase for field Daphnia populations demonstrated that life history traits of exephippial animals lead to a two or threefold higher rate of increase in the conditions of invertebrate predation pressure. Under moderate fish pressure, obtained r values for the daphniids hatching from resting eggs were larger than those from subitaneous. High growth rate of exephippial females is disadvantageous only under the conditions of severe pressure by fish. Obtained results suggest that hatchlings from diapausing eggs an acceleration of population increase by several times during the beginning of the development of a population with periodical re-establishment from resting eggs.
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  • 70
    ISSN: 1573-5117
    Keywords: Sediment bioassay ; Oligochaeta ; Tubifex tubifex ; Branchiura sowerbyi ; growth ; reproduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two tubificid oligochaetes, Branchiura sowerbyi and Tubifex tubifex, were evaluated as potential test organisms for sediment bioassays. We attempt to reproduce the sediment bioassay proposed by Reynoldson et al. (1991) using his strain of Tubifex tubifex and his reference sediment and to compare this technique using Branchiura sowerbyi. This species was chosen because it is more common and dominant in tropical and subtropical environments than Tubifex tubifex. Data on survival and reproduction were obtained for both species, and growth estimates were obtained for B. sowerbyi. The sublethal bioassay with T. tubifex confirmed earlier estimates of a test duration of 4 weeks at 22.5 °C. B. sowerbyi cultures can produce usable estimates in 21 days at 30 °C.
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  • 71
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    Hydrobiologia 334 (1996), S. 207-217 
    ISSN: 1573-5117
    Keywords: haplotaxids ; helical muscles ; ultrastructure ; growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract There are two different muscle fiber types in haplotaxids. The pseudo-circomyarian type is typical of Haplotaxis gordioides and the flattened circomyarian type of Pelodrilus leruthi. The mechanisms of growth in fiber size and in fiber number of the two fiber types in the hindmost region of adult specimens have been studied ultrastructurally. The increase in length and girth of the muscle fiber is always the result of the insertion of new myofilaments in the peripheral zones of the muscle cells. The increase in the number of fibers seems to be due to division of differentiated muscle cells.
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  • 72
    ISSN: 1573-5117
    Keywords: toxicity ; cultures ; oligochaetes ; T. tubifex ; growth ; reproduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Reproduction in Tubifex tubifex is being used as part of a suite of indicators of sediment toxicity in Canada and Spain, and reproduction of T. tubifex is being considered as a component of sediment objectives for environmental regulation and clean-up in the Canadian Great Lakes. The data being used to set these reproductive targets have been developed from a single culture of T. tubifex from Lake Erie. The plasticity of this particular species is well known and before it can be adopted widely as a test organism it is necessary to determine whether a single culture source should be used or if cultures derived from different populations respond similarly. A series of experiments with two cultures, one from Lake Erie the second from a small mountain stream in Northern Spain have shown that the Spanish worms appear to produce fewer cocoons per adult (mean 8.6 S.D. 1.0) than those from Lake Erie (mean 10.4 S.D. 0.3) at 22.5 °C, a standard test temperature. The number of young produced per adult by the Spanish culture is also lower (mean 19.0 S.D. 4.6) than the L. Erie population (mean 30.6 S.D. 2.3), however, the Spanish population has higher reproductions rates at a lower temperature. The Spanish worms also have lower and more variable growth rates than the Canadian population. There also appear to be slight differences in the sensitivities to toxicants, with the Canadian worms having higher LC50s for copper, chromium and cadmium. While there are differences in the responses in the two cultures these are not considered to be sufficient to invalidate the use of either population in a standard bioassay protocol as long as appropriate calibration and validation are undertaken.
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  • 73
    ISSN: 1573-5117
    Keywords: weedbed ; growth ; physiology ; pH ; oxygen ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In slow-moving and static eutrophic waters, submerged macrophytes growing in dense stands produce a highly structured environment, with reduced internal water flow. An afternoon lull in the net photosynthesis of such stands has been reported from a number of previous studies. This has been attributed to increased photorespiration caused by an accumulation of photosynthetically-derived, dissolved oxygen in the surrounding water. Results here demonstrate that even in a water quite rich in dissolved inorganic carbon (2.5 mmol l−1), limitations on the supply of inorganic carbon will normally be more important in curtailing photosynthesis, with photorespiration playing only a minor role.
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  • 74
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    Hydrobiologia 341 (1996), S. 113-123 
    ISSN: 1573-5117
    Keywords: bacteria ; protist ; flagellate ; ciliate ; growth ; activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The trophic link between bacteria and bacterivorous protists is a complex interaction that involves feedback of inorganic nutrients and growth substrates that are immeadiately available for prey growth. These interactions were examined in the laboratory and in incubations of concentrated natural assemblages of bacterioplankton. Growth dynamics of estuarine and marine bacterivorous protists were determined in laboratory culture using Vibrio natriegens as prey and were compared to growth of protists on bacterioplankton assemblages concentrated by tangential flow filtration from four northwest Florida Estuaries. Biomass transfers from bacteria to protists were monitored by tracing elemental carbon and nitrogen in particulate fractions of protist added and grazer free controls. Gross growth efficiencies of the protists on naturally occurring bacteria were within the range determined in lab estimates of growth efficiency on cultured bacteria (∼50%). However, bacterial response to protist excretion products was different in the lab and field incubations, and bacterial growth contributed to the biomass available to protists in the field incubations. As determined by radioisotope-labeled substrate incorporation, a time lag in bacterial reponse to protist excretion products was observed for laboratory batch cultures, allowing accurate estimation of growth efficiency. In incubations with concentrated natural bacterial assemblages, bacterial growth response coincided with protist growth and excretion. The additional bacterial production on protist excretion products reached a maximum of 2–3-fold higher than protist-free controls. In addition, ammonium concentrations increased with protist grazing and growth in lab cultures, but ammonium excreted by protists in concentrates did not accumulate. The C:N values for the bacterial concentrates suggests that these bacteria were nitrogen limited. It is speculated that dissolved organic carbon, concentrated by tangential flow filtration (〉 100,000 MW membrane) with the bacterioplankton, was utilized by bacteria when nitrogen was supplied as ammonium and amino acids from protist excretion. Thus, estimates of protist growth efficiency on naturally occurring bacterioplankton, corrected for protist-stimulated bacterial production, were in the range of 13–21%.
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  • 75
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    Hydrobiologia 326-327 (1996), S. 67-73 
    ISSN: 1573-5117
    Keywords: growth ; kelp ; Laminaria ; Nereocystis ; nutrient removal ; technical and economical feasibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Critical aspects of growing Laminaria saccharina and Nereocystis luetkeana near salmon sea cages are discussed. A new computer spreadsheet model was developed, which integrated biological, physical and economic aspects of kelp/salmon cultivation, in order to provide information on production, nutrient removal, and technical and economic feasibility of different production strategies. Given a farm-gate price of $20 kg−1 (dry mass) and either a 24 or 48 sea cage salmon farm, kelp is a feasible investment option. Results of the model suggest that kelp apparently obtains ammonium for growth during slack tide and that ammonium uptake is also significant during that time. The net yield of Nereocystis needs to be increased before it can compete with the yield of Laminaria. To include kelp on a salmon farm, a part-time position and a separate mooring system for kelp would be needed. Special attention should be given to training personnel in both salmon and kelp production.
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  • 76
    ISSN: 1573-5117
    Keywords: Arthrospira ; Chitu ; Ethiopia ; growth ; light ; nutrient status ; quantum yield ; Spirulina
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Spirulina platensis (= Arthrospira fusiformis) was isolated from Lake Chitu, a saline, alkaline lake in Ethiopia, where it forms an almost unialgal population. Optimum growth conditions were studied in a turbidostat. Cultures grown in modified Zarrouk's medium and exposed to a range of light intensities (20–500 µmol photons m−2s−1) showed a maximum specific growth rate (µmax) of 1.78 d−1. Quantum yield for growth (Φµ) was 3.8% at the optimum light for growth of 330 µmol photons m−2s−1, and ranged from 2.8 to 9.4%. With increase in irradiance, the chlorophyll a concentration decreased, and the carotenoids/chlorophyll a ratio increased by a factor of 2.4. The phosphorus to carbon ratio (P/C) showed some variation, while the nitrogen to carbon ratio (N/C) remained relatively constant, thus causing fluctuations in the N:P ratio (7–11) of cells. An optimum N:P ratio of about 7 was attained in cells growing at the optimum light for growth. Results from the continuous culture experiments agreed well with maximum values of photosynthetic efficiency given in the literature for natural populations of S. platensis in the soda lakes of East Africa, Lake Arenguade (Ethiopia), and Lake Simbi (Kenya).
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  • 77
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    Hydrobiologia 341 (1996), S. 215-224 
    ISSN: 1573-5117
    Keywords: Gambusia holbrooki ; Poeciliidae ; growth ; reproduction ; life history tactics ; Mediterranean estuary
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We studied age, growth and reproduction of an introduced poeciliid, Gambusia holbrooki (Agassiz, 1859), in the Ebro delta marshes. Maximum ages observed were 2+ in females and 0+ in males. Growth commenced in March and continued until September. Females reached greater sizes, had a higher rate of growth and lived longer than males. The largest sizes found were 63 mm ♀♀ versus 32 mm ♂♂. Multiple spawning occurred throughout the reproductive cycle (from May to September). The average brood size per female reached its maximum in July in the parental cohort (86 embryos/♀) and in August in the offspring cohort (29 embryos/♀). After reproduction the parental cohort decreased drastically. The relationship between fecundity (F) and total length (mm) was calculated for each month of the reproductive period. Sex-ratio deviated significantly from unity. Viviparity, several broods and large larvae provide G. holbrooki with several advantages over oviparous species. The capacity to adjust its life history to a particular environment could explain the life history differences between those in the Ebro delta and other populations.
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  • 78
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    Journal of economic growth 1 (1996), S. 1-27 
    ISSN: 1573-7020
    Keywords: growth ; democracy ; freedom ; rule of law ; O40 ; O57
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract Growth and democracy (subjective indexes of political freedom) are analyzed for a panel of about 100 countries from 1960 to 1990. The favorable effects on growth include maintenance of the rule of law, free markets, small government consumption, and high human capital. Once these kinds of variables and the initial level of real per capita GDP are held constant, the overall effect of democracy on growth is weakly negative. There is a suggestion of a nonlinear relationship in which more democracy enhances growth at low levels of political freedom but depresses growth when a moderate level of freedom has already been attained. Improvements in the standard of living—measured by GDP, health status, and education—substantially raise the probability that political freedoms will grow. These results allow for predictions about which countries will become more or less democratic over time.
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    Journal of economic growth 1 (1996), S. 149-187 
    ISSN: 1573-7020
    Keywords: income distribution ; growth ; fertility ; political instability ; O1 ; H5
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract This paper investigates the relationship between income distribution, democratic institutions, and growth. It does so by addressing three main issues: the properties and reliability of the income distribution data, the robustness of the reduced form relationships between income distribution and growth estimated so far, and the specific channels through which income distribution affects growth. The main conclusion in this regard is that there is strong empirical support for two types of explanations, linking income distribution to sociopolitical instability and to the education/fertility decision. A third channel, based on the interplay of borrowing constraints and investment in human capital, also seems to receive some support by the data, although it is probably the hardest to test with the existing data. By contrast, there appears to be less empirical support for explanations based on the effects of income distribution on fiscal policy.
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  • 80
    ISSN: 1573-8590
    Keywords: brackish marsh ; growth ; light attenuation ; submerged macrophyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract The development of submerged plant communities dominated byRuppia drepanensis Tineo in the brackish marsh of the Doñana National Park (SW Spain) was coupled to seasonal variation in environmental factors for two consecutive years. Plant biomass increased rapidly in early spring (March), with steady biomass yields (up to 100 g afdw m−2) together with abundant flowering and fruiting in late spring (April–May). Wind-induced sediment resuspension and periphyton growth strongly influenced the light climate experienced by the submerged vegetation, while a phytoplankton effect was generally negligible. Development of the submerged vegetation coincided with a decrease in water extinction coefficient and in bicarbonate concentration. Thus, where dense macrophyte meadows develop, light climate probably is the limiting factor in the early spring, while temperature and bicarbonate levels are so by the end of the season. Interannual variation was found to be very high, both in abundance and distribution of the submerged vegetation, mainly because of differences in rainfall which influenced the inundation cycle. Grazing by waterfowl accounted also for this effect, as in dry years birds concentrate in the few wetlands still containing water.
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  • 81
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    Journal of economics 63 (1996), S. 279-302 
    ISSN: 1617-7134
    Keywords: general equilibrium ; imperfect competition ; growth ; price normalization ; D43 ; D51 ; O41
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract We consider a capital-accumulation model with infinitely lived households and two production sectors. The intermediate-good sector is characterized by perfect competition, a constant-returns-to-scale technology, and production externalities. The final-good sector is a monopoly operating under constant returns to scale. We analyze the general equilibrium in the sense of Gabszewicz and Vial [Journal of Economic Theory (1972) 4: 381–400] for this economy and different price-normalization rules. It is shown that the qualitative behavior of the equilibrium paths depends crucially on the chosen normalization rule. In particular, whether equilibria are monotonic or oscillating and whether indeterminacy occurs or not may depend on the choice of the numeraire.
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  • 82
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    Colloid & polymer science 274 (1996), S. 209-217 
    ISSN: 1435-1536
    Keywords: Crystallization ; nucleation ; growth ; non-isothermal crystallization ; thermal nucleation ; athermal nucleation ; transient effects ; relaxation times
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A new model of crystallization kinetics in variable external conditions has been developed. The model concerns situations when temperature, pressure, stress, change in time. Compared to earlier models, the present treatment includes transient and athermal effects, proportional to the rate of change of the external conditions. The model can be used for simulation of crystallization in industrial processes (injection molding, fiber spinning, film blowing). The present paper offers general theoretical fundamentals of the model. Applications concerning more specific cases will be published separately.
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  • 83
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    Plant and soil 184 (1996), S. 281-289 
    ISSN: 1573-5036
    Keywords: chlorosis ; growth ; iron ; nitrogen ; phosphate ; soil acidity ; zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Veronica officinalis and Carex pilulifera, widespread plants of acid soils in Europe, were grown in 50 soils of natural and seminatural ecosystems representing a wide range of soil chemical properties. The experiment was performed in a greenhouse at a soil moisture content of 55–65% WHC, ca. 60% R.H. of the air, temperature 14–16°C at night and 19–21°C by day; additional light 70 W m-2 12 h d-1. Properties closely related to soil acidity precluded growth of V. officinalis and limited the growth rate of C. pilulifera at soil pH-KCl 〈 ca. 3.4. In slightly-moderately alkaline (calcareous) soils, growth was primarily limited by insufficient phosphate uptake. A low growth rate of C. pilulifera. in such soils was related to low concentrations of exchangeable soil phosphate and low tissue concentrations of phosphorus. However, in high-pH soils, secondary effects due to suboptimum trace element (probably Fe) conditions, giving rise to symptoms of chlorosis, were also indicated. The highest growth rates of both species were invariably measured in soils of intermediate acidity having very high concentrations of exchangeable phosphate. Multiple regression tests on the entire material indicated that 65–75% of the variability in several growth functions could be accounted for, when two or more soil characters were included in the equation. Besides phosphate, exchangeable Zn (in C. pilulifera) and nitrate (in V. officinalis) were of considerable importance in accounting for growth rates.
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  • 84
    ISSN: 1573-5036
    Keywords: barley ; crown roots ; growth ; nitrate reductase ; nitrate uptake ; seminal roots ; solution culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Barley (Hordeum vulgare L., cvs Golf and Laevigatum) was grown under nitrogen limitation, controlled by the relative rate of nitrate-N addition (RA), in solution culture. The seminal and crown root systems were kept apart, but in contact with the same nutrient solution throughout culturing. Growth, nitrate uptake, and in vitro nitrate reductase (NR) activity in the different root parts were studied at plant ages from 40 (late vegetative stage) to 110 (mid grain-filling) days. The RA was during this time interval stepwise decreased from 0.08 day−1 to 0.005 day−1. The ratio between seminal root dry weight and total plant dry weight decreased drastically during post-anthesis growth, whereas the contribution by crown roots remained unchanged. Tissue nitrogen concentrations in seminal roots did not change with time, but decreased in crown roots after day 80. The NR activity decreased with age in both seminal and crown roots. The Vmax for net nitrate uptake decreased throughout the experiment in the seminal root system, but not in the crown root system. The kinetic properties (Vmax and KM) were used to calculate the nitrate concentration required to maintain a relative rate of nitrate-N uptake that equals the relative addition rate. These concentrations (2 to 5 mmol m−3) were found to closely match actually measured nitrate concentrations in the nutrient solution (1 to 6 mmol m−3). From uptake kinetics, it was deduced that the contribution by seminal roots to total nitrate uptake at these concentrations decreased from more than 50% in vegetative plants, to about 20% just after main shoot anthesis, and to less than 5% during grain-filling. ei]Section editor: H Lambers
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  • 85
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    Plant and soil 155-156 (1993), S. 415-418 
    ISSN: 1573-5036
    Keywords: Brassica ; calcium ; growth ; salinity ; salt tolerance ; seawater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Whole plant and callus cultures of different rapid-cycling Brassica species were treated with salinity (8 dS m-1) and/or supplemental Ca (up to 10 mM total concentration). None of these cultures responded to supplemental Ca with improved growth indicating that the salt tolerance of these genotypes was not dependent upon Ca.
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    Plant and soil 155-156 (1993), S. 191-194 
    ISSN: 1573-5036
    Keywords: amino acids ; biomass partitioning ; growth ; Spinacia oleracea ; sugars ; starch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Theoretical plant growth models postulate an important role for growth substrates such as sugars and amino acids. To test this experimentally, spinach plants were grown under controlled conditions and with nitrogen added daily, following different exponential addition schemes. Plants were harvested during exponential growth. Free amino acid levels or free sugar levels were only weakly correlated with growth and biomass partitioning. Factor analysis showed however that the product of free sugar concentration and amino acid concentration yielded a parameter adequately reflecting the plant's nutritional state. It is concluded that growth and biomass partitioning under limiting N conditions cannot be modelled solely based on N substrate levels.
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  • 87
    ISSN: 1573-5036
    Keywords: ammonium ; carbohydrates ; carboxylates ; cultivar ; growth ; nitrate ; xylem exudate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Variations in the inorganic and organic composition of xylem exudate, growth and N content under contrasting forms of N supply in three cucumber cultivars (Hyclos, Medusa and Victory) were studied in glasshouse conditions. The plants were grown hydroponically with two NO3 -:NH4 + ratios (100:0 and 60:40). The xylem sap of Medusa grown with both N sources displayed an increase of organic N and carboxylate concentrations and a decrease of cations, inorganic anions and carbohydrates compared with that of those grown with NO3 - alone, showing a higher growth and N content in tissues and thus better utilization of N supplied as NO3 - and NH4 +. Mixed N nutrition in Hyclos caused the greatest amounts of NO3 - and NH4 + in xylem sap, lower root weight and N levels in the leaves, while its root was unable to generate an adequate supply of organic N compounds. Despite the levels of cations, inorganic and organic anions were reduced by the NH4 + supplied to Victory, the ionic balance in the xylem sap, growth and N content remained similar to that of those supplied with NO3 - alone. Finally, the cucumber cultivars studied here, responded differently to the form of N supplied, it may partly be due to their ability of assimilating N in the roots and partly to the form in which the N is translocated to the shoot.
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  • 88
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    Plant and soil 187 (1996), S. 57-66 
    ISSN: 1573-5036
    Keywords: compensation ; growth ; heterogeneity ; inflow ; nutrient ; roots ; soil ; variability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In soil, the distributions of nutrients, water, pores, and microbes vary in time and space. These, in turn, contribute to the variations in root form and function that we see when we grow plants in soil and other non-uniform media. This paper addresses three questions about the consequences of non-uniform distributions of nutrients: how do roots respond to variations in nutrient distribution?; how specific are such responses?; to what extent can we predict them? Roots vary both physiologically and structurally in response to nutrient distributions. The first type of response is primarily a stimulation of nutrient uptake rate per unit of root; the second, a stimulation of root growth where and when the nutrient is most readily available. The first tends to be nutrient-specific and its magnitude related to the extent of the non-uniformity in nutrient availability. The second is less-specific in the sense that the magnitude of the response, when there is one, varies little from one nutrient to another. This leads to apparently exaggerated compensatory capacity, especially for ions that are relatively mobile in soil, such as NO3 -. Because the physiological and molecular mechanisms of these responses are largely unknown, we cannot say how they are co-ordinated within individual plants. Nor can we predict a plant's responses precisely. What we can do is generate statistical descriptions of them by comparing data collected in many experiments for many species. This produces general rules that summarise what happens, but which probably cannot be applied a priori to specific cases. H Lambers Section editor
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    Plant and soil 155-156 (1993), S. 285-288 
    ISSN: 1573-5036
    Keywords: Trifolium subterraneum ; seed phosphorus ; emergence ; growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Subterranean clover seed (Trifolium subterraneum cv. Dalkeith) with phosphorus concentrations of 0.75% (high P seed) and 0.48% (low P seed) and of uniform size (2.0–2.4 mm diameter) was used to measure the effect of seed P concentrations on seedling emergence and growth. Seedling emergence numbers were 35% greater for the high P seed, and this effect was independent of external P supply. High P seed also emerged more quickly than low P seed. Leaf emergence was faster and shoot dry weight was greater for seedlings grown from high compared with low P seed, but only when external P supply was deficient for plant growth. Phosphorus concentrations in the shoots of two-week old seedlings were 32–51% higher for high P seed, although by four weeks plants grown from high and low P seed had similar concentrations of P in their shoots. We suggest that establishing pastures using high P seed would improve both early and late season pasture production.
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    Plant and soil 180 (1996), S. 231-240 
    ISSN: 1573-5036
    Keywords: chrysanthemum ; diffusion ; growth ; model ; roots
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Simulations of crop productivity and environmental quality depend strongly on the root activity model used. Flexible, generic root system models are needed that can easily be coupled to various process-based soil models and can easily be modified to test various hypotheses about how roots respond to their environment. In this paper, we develop a convective-diffusive model of root growth and proliferation, and use it to test some of these hypotheses with data on the growth of roots on potted chrysanthemum cuttings. The proliferation of roots is viewed as a result of a diffusion-like gradient-driven propagation in all directions and convection-like propagation downwards caused by geotropism. The finite element method was used to solve the boundary problem for the convective-diffusive equation. To test hypotheses, we wrote modules in a way that caused a test parameter to be zero, should the hypothesis be rejected. These modules were added or removed to test each hypothesis in turn and in various combinations. The model explained 92% of the variation in the experimental data of Chen and Lieth (1993) on root growth of potted chrysanthemum cuttings. For this dataset the following hypotheses were accepted: (1) root diffusivity (colonization of new soil) did not depend on root density, (2) there was no geotropic trend in root development, (3) potential root growth increased linearly with root density, (4) there were (at least) two classes of roots with different rates of growth and proliferation, and (5) potential root growth rate decreased with distance from the plant stem base.
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  • 91
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    Plant and soil 186 (1996), S. 39-43 
    ISSN: 1573-5036
    Keywords: acetylene reduction ; drought ; drought-avoidant germplasm ; Glycine max (L.) Merrill ; growth ; nitrogen ; assimilation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Inoculated soybeans (Glycine max L. (Merrill)) were grown in controlled environments to evaluate the relationship between genotype and plant water status on nodule function, nitrogen assimilation, growth rates, and seed yield. Plants were grown under well-watered (WW) and water-stressed (WS) conditions during the linear pod-filling growth stage in sand culture using N-free nutrient solution. Dry matter and N accumulation were greater for the drought-adapted Plant Introduction 416937 (PI) than for ‘Forrest’, a commercially adapted genotype of similar phenology. These differences are attributed to: (i) more favorable internal water balance throughout the pod-filling period (higher total leaf water potential), (ii) higher photosynthetic function (more total leaf area and higher net carbon exchange rates), and (iii) stronger nodule function (larger nodule mass, greater specific and total nodule activity, and thus more nitrogen assimilation) for the PI than for Forrest. While Forrest out yielded the PI under WW conditions, the percentage reduction in seed mass per plant was less for the PI than for Forrest when both genotypes were exposed to desiccating conditions. The inference is that soybean germplasm with the capacity to maintain tissue turgidity, and thus leaf and nodule function, during reproductively-imposed desiccation may reduce the extent to which yield is compromised during drought. These findings have implications for the role of symbiotic nitrogen fixation in conserving yield under dry weather conditions.
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  • 92
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    Plant and soil 153 (1993), S. 243-254 
    ISSN: 1573-5036
    Keywords: Al speciation ; centrifugation ; flowing solution culture ; growth ; soil solutions ; tissue mineral concentration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract One pH experiment and two aluminium experiments were conducted in order to investigate the effects of H- and Al ions on growth of Bromus benekenii. Continuously flowing solution cultures were used with ion concentrations simulating natural soil solutions. In all experiments, treatment effects were more pronounced on root than on shoot growth. In the pH experiment, root growth decreased with decreasing pH within the pH range 4.5 to 3.5. The critical pH for root growth of Bromus benekenii was between 3.8 and 4.0. In the Al experiments, root growth started to decrease at 20 μM of quickly reacting Al and almost ceased at 70 μM Al. This characterizes Bromus benekenii as an Al sensitive species. In the pH experiment, shoot concentrations of Ca, Mg, K and P decreased with decreasing pH, but root concentrations were not affected. In the Al experiments, the Al concentrations of both shoots and roots increased with Al in the nutrient solution. At treatments of 70 μM Al or higher, Ca, Mg, K and P concentrations in the shoots were reduced. The critical concentrations of H- and Al ions in the experiments were similar to the highest concentrations found at field sites of Bromus benekenii, analysed in soil solutions obtained by centrifugation technique. Both Al and H toxicity were considered to be of importance as limiting factors for the distribution of Bromus benekenii in south Sweden. Probably, Al toxicity starts to limit growth when also pH itself influences growth negatively. The importance of simulating natural soil solutions in experiments is emphazised, in order to obtain information on the importance of chemical soil factors to the distribution of plants.
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  • 93
    ISSN: 1573-5036
    Keywords: Frankia ; growth ; immobilization ; nitrogenase activity ; spores ; sporulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Spores of Frankia strain ACN1AG, immobilized in calcium alginate beads, germinated to produce colonies that increased in protein content and showed nitrogenase activity. Air dried immobilized spores remained viable for at least 15 days in dry condition, making the storage and transport of Frankia strains easy. This also opens the possibility of using beaded spores as inocula.
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  • 94
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    Plant and soil 182 (1996), S. 259-265 
    ISSN: 1573-5036
    Keywords: growth ; loblolly pine ; 32P labeling ; phosphorus efflux ; phosphorus uptake ; Pinus taeda L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Short-term 32P uptake experiments were conducted with intact seedlings of loblolly pine (Pinus taeda L.) to examine possible seed source variation in net accumulation of 32P in roots and shoots, and in rates of unidirectional influx. Seed source had a highly significant effect on biomass and P concentrations of shoots and roots. Seedlings from two seed sources representing fast-growing populations (a broadly-adapted and wet-site seed source) accumulated over 60% more total seedling P than smaller seedlings from a drought-hardy seed source, reflecting higher biomass and root P concentrations. Rates of unidirectional 32P influx in seedlings from the drought-hardy seed source were more than twice the rates of the seedlings from the broadly-adapted seed source. However, after 24 h in labeled uptake solution, net accumulation of 32P was similar, suggesting that rates of unidirectional efflux from roots of the drought-hardy seed source were also high. Although there were no significant differences in biomass and tissue P concentrations between the two fast-growing seed sources, rates of unidirectional influx in seedlings from the broadly-adapted seed source were 42% lower than rates in seedlings from the wet-site source. Yet, after 24 h in labeled uptake solution, net accumulation of 32P in seedlings from the broadly-adapted seed source was 50% higher. Unidirectional efflux out of the root may regulate net uptake of P as much, if not more, than influx in loblolly pine seedlings-at least under high-P growth conditions. The results in this study do not support previous studies with herbaceous plants suggesting that fast-growing species typically exhibit higher rates of nutrient uptake than slow-growing species.
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  • 95
    ISSN: 1573-5036
    Keywords: aluminium ; ericoid mycorrhizae ; growth ; infection ; nutrient uptake ; Vaccinium corymbosum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A factorial experiment was conducted to determine the effect of aluminium (0 and 600μM) and media (sand, and 1:1 sand:soil) on mycorrhizal (M) and non-mycorrhizal (NM) highbush blueberry plantlets. There were no differences in nutrient uptake and total plant dry weight between M and NM plantlets. However, more root growth, as determined by dry weight, was observed in M than NM plantlets. The plantlets growing in sand had more dry weight than did those in the soil medium. Although the root growth and shoot growth were reduced by the 600μM Al treatment, the direct effect of Al on plantlet growth was not clear due to Al and P interactions. Plant nutrient uptake was reduced by high concentrations of Al, suggesting that high Al concentration limited the ability of roots to acquire most of the nutrients. Mycorrhizal cortical cell infection levels of 15–20% wene maintained in the roots in soil medium but decreased to about 5% over the 6 weeks of the experiment in the sand medium. Although M plantlets accumulated more Al in their roots, Al was readily transported to the leaf tissues of M and NM plantlets.
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  • 96
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    Plant growth regulation 12 (1993), S. 133-140 
    ISSN: 1573-5087
    Keywords: gibberellins ; paclobutrazol ; GC-MS ; safflower ; Carthamus tinctorius ; growth ; yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Endogenous gibberellins (GAs) were extracted from safflower (Carthamus tinctorius L.) stems and detected by capillary gas chromatography-mass spectrometry from which GA1, GA3, GA19,, GA20, GA29, and probably, GA44 were detected. The detection of these GAs suggests that the early 13-OH biosynthetic pathway is prevalent in safflower shoots. Deuterated GAs were used as internal standards and GA concentrations were determined in stems harvested at weekly intervals. GA1 and GA19 levels per stem increased but concentrations per gram dry weight decreased over time. GA20 was only detected in young stem tissue. Gibberellic acid (GA3) was also applied in field trials and both GA3 and the GA biosynthetic inhibitor, paclobutrazol, were applied in growth chamber tests. GA3 increased epidermal cell size, internode length, and increased internode cell number causing stem elongation. Conversely, paclobutrazol reduced stem height, internode and cell size, cell number and overall shoot weight. In field tests, GA3 increased total stem weight, but decreased leaf weight, flower bud number and seed yield. Thus, GA3 promoted vegetative growth at the expense of reproductive commitment. These studies collectively indicate a promotory role of GAs in the control of shoot growth in safflower, and are generally consistent with gibberellin studies of related crop plants.
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  • 97
    ISSN: 1573-5095
    Keywords: freeze-desiccation ; boreal forest ; planting ; roots ; growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Foliar and stem injury was assessed in white spruce (Picea glauca (Moench) Voss) seedlings planted in the spring and in the summer of 1992 and injured during their first overwintering on two sites in the southeastern boreal forest of British Columbia. Freeze-desiccation appears to be the main cause of the injury. Seedlot effect on the injury was significant, while planting time effect was not. Although the seedlot effect may be confounded with stock-type effect, analyses indicated increasing injury with increasing seedling height and declining ground-level diameter. Seedling vigour (height and diameter increments in the previous growing season) was also significantly related to the injury which increased with increasing vigour but the significance of this relationship varied from site to site. Condition of injured seedlings generally declined further during the post-injury growing season. This decline was greater in spring-planted than in summer-planted seedlings. Excavated root systems of container-grown seedlings showed the majority of post-planting root growth originating from the bottom-third of the nursery-container plug, deeper than 10 cm from the soil surface. This is seen as a factor potentially contributing to desiccation injury as the soil in the geographic region often remains frozen at these depths long into spring.
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  • 98
    ISSN: 1573-5117
    Keywords: Zostera noltii ; Cymodocea nodosa ; growth ; seagrass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Leaf dynamics and standing stocks of intertidal seagrasses were studied in the Baie d'Aouatif (Parc National du Banc d'Arguin, Mauritania) in April and September 1988. Standing stocks of Zostera noltii Hornem. suggest a unimodal seasonal curve similar to what is found for populations at higher latitudes. Also, leaf growth rates (0.03 cm2 cm−2 day−1 on average) were similar to those found at higher latitudes in these months. Variation in leaf loss over tidal depth, time and different locations in the Baie d'Aouatif was larger and more often significant than variation in leaf growth. In general, Z. noltii beds in the Baie d'Aouatif had comparable leaf growth rates and standing stocks. In both months losses were almost always higher than or equal to growth. Variation in leaf loss over time was much higher in the plots that were situated high in the intertidal than in lower plots. This is explained by differences in susceptibility to sloughing, which is presumably higher in periods with low tide around noon for shallow depths. In an experiment using artificial shading nets, in situ leaf growth was affected negatively from 94% shading onwards. This shading was observed to reduce the light intensity reaching the seagrass bed to a level below the reported range of light compensation points for Z. noltii. Cymodocea nodosa (Ucria) Ascherson on average had higher leaf area and relative growth rates than Z. noltii and much lower loss rates, resulting in a positive net increase in September. Standing stocks were also higher than for Z. noltii. A mixed seagrass bed containing the above two species and Halodule wrightii Ascherson had the highest observed total biomass: 335 g m−2 ash-free dry weight.
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  • 99
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    Hydrobiologia 268 (1993), S. 169-178 
    ISSN: 1573-5117
    Keywords: agar ; cultivation ; gel strength ; Gelidium pristoides ; growth ; mariculture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The economically important agarophyte Gelidium pristoides was cultivated at different depths in the ocean in Algoa Bay between March and June 1991. The seaweed was either tied to ropes (whole tufts on limpet shells) or sewn into net bags (plucked fronds only) supported on metal frames. All experiments were run for between 5 and 8 weeks. Growth, agar content and, in one experiment, agar gel strength was measured weekly or fortnightly. Plants in net bags increased their biomass during the first 2 weeks of the experiment but only surface plants had a significantly higher biomass (approx. 20%) by week 2. From the second week fronds rapidly accumulated sediment, became discoloured, and then degenerated from week 3 onward. The agar content of net-grown plants was significantly increased from 32% to 38% in subsurface plants after one week. Thereafter agar content declined steadily as the thalli degenerated. Plants growing on limpet shells survived submersion much better than net-grown plants cultivated at the same time. The practise of wiring shells to ropes was unsatisfactory because this damaged the shells and caused a loss of seaweed biomass. Surface plants did however increase their biomass by up to 19% after 8 weeks in this experiment, but the increases could not be shown to be statistically significant because of high data variance. Surface thalli in this experiment also increased their agar content significantly from 32% to 42% after one week but from weeks 4–8 this dropped off. A second experiment using shells was conducted when sea temperatures had dropped by as much as 5 °C. These plants remained healthy throughout the study and maintained their starting biomass for 2 weeks but then lost biomass as sea temperatures declined further. The agar content of these thalli increased during the first 2 weeks with surface thalli at week 2 having significantly higher agar contents (38–48%) compared with a starting value of 22%. The gel strength of agar extracted from these plants increased significantly during the first three weeks of submersion, in some cases doubling from an initial gel strength of 300 g cm−2 to 600 g cm−2.
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  • 100
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    New forests 7 (1993), S. 63-92 
    ISSN: 1573-5095
    Keywords: seedling morphology ; nursery ; survival ; growth ; economics ; performance potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Although most bare-root pine seedlings in the Southern United States are grown at seedbed densities near 300/m2, the density used in other regions of the world is often less than 200/m2. One rationale for growing seedlings at lower seedbed densities is based on the desire to reduce the time required for successful stand establishment. Achieving a one- to two-year advancement in stand establishment can result in an additional 15 to 30 m3/ha within 15 to 20 years. Although seedling grade studies have demonstrated similar gains in volume production at ages 10 to 30 years, the findings from these studies are not widely known. The rationale in the Southern United States for growing at higher seedbed densities appears to be based on: (1) misinformation regarding the performance of morphologically improved seedlings; (2) a desire to minimize seedling and planting costs; and (3) density recommendations that are not based on volume growth in the field.
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