ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

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A Pipeline Testing Facility for the Examination of Pipe-Wall Deposits and Red-Water Events in Drinking Water (1999)

Smith, S. E. ; Ta, T. ; Holt, D. M. ; [et al.]

Oxford, UK : Blackwell Publishing Ltd

Water and environment journal 13 (1999), S. 0

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ISSN: 1747-6593

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Energy, Environment Protection, Nuclear Power Engineering

Notes: Field surveys of Thames Water's distribution mains found the occurrence of ‘red water’ to be highly variable and localized. To model the many inter-related factors identified in the field, a controlled pipeline-testing facility was required to simulate conditions in a ‘live’ network, but on a pilot-scale. This was achieved by incorporating a specialized red-water testing facility into an existing experimental pipeline.This paper describes the hydraulic and material design features, including the addition of a ‘dead-end’ section operated on a stagnation and flow regime, quantified using computational fluid dynamics. Following commissioning, the facility has provided detailed, time-sequenced observations on corrosion-deposit development and red-water generation under different hydraulic regimes.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1747-6593.1999.tb00999.x

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2

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Variation in generative cell plastid nucleoids and male fertility in Medicago sativa (1995)

Keys, R. N. ; Smith, S. E. ; Mogensen, H. L.

Springer

Sexual plant reproduction 8 (1995), S. 308-312

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ISSN: 1432-2145

Keywords: Alfalfa ; Chloroplast ; Organelle inheritance ; Pollen

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Biparental inheritance of plastids has been documented in numerous angiosperm species. The adaptive significance of the mode of plastid inheritance (unior biparental) is poorly understood. In plants exhibiting paternal inheritance of plastids, DNA-containing plastids in the microgametophyte may affect survival or growth of the gametophyte or the embryo. In this study the number of plastids containing DNA (nucleoids) in generative cells and generative cell and pollen volumes were evaluated in a range of genotypes of Medicago sativa (alfalfa). M. sativa exhibits biparental inheritance of plastids with strong paternal bias. The M. sativa genotypes used were crossed as male parents to a common genotype and the relationships between the gametophytic traits measured and male reproductive success were assessed. Generative cell plastid number and pollen grain size exhibited opposing associations with male fertility. Path analysis showed that generative cell plastid number was negatively associated with male fertility. This study provides evidence that there may be a competitive advantage at fertilization afforded sperm that have minimized their organelle content. The apparent lack of strong selection for reduced plastid number in generative cells of M. sativa may be a reflection of the diminished importance of reproductive success due to its perenniality or its long use in cultivation.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00229388

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3

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Crown moisture and prediction of plant mortality in drought-stressed alfalfa (1997)

Wissuwa, Matthias ; Smith, S. E. ; Ottman, Michael J.

Springer

Irrigation science 17 (1997), S. 87-91

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ISSN: 1432-1319

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract Withholding alfalfa (Medicago sativa L.) irrigations during the summer, a practice referred to as summer irrigation termination (SIT), can conserve substantial amounts of water in long-season desert environments; however, plant mortality associated with SIT may be substantial. Proper timing of re-irrigation is critical for minimizing mortality and yield reductions following SIT. Procedures that would permit probable mortality prediction during drought stress would improve management efficiency with SIT. This study was conducted to determine (1) whether plant mortality occurs once the moisture content of the plant woody stem portions (crown) falls below some critical threshold and (2) if such a threshold could be used to predict the likelihood of plant mortality during SIT. Crown samples were taken from single, spaced, field-grown plants in Tucson, Arizona, at the end of a 84-day SIT period in 1994. A crown moisture content of about 42% was identified as a likely threshold critical for crown tissue SIT survival. This value was then used to predict whole-plant mortality of alfalfa grown in solid-seeded plots comparable to commercial fields. Crown samples were taken at five locations within the field along a solid gradient that was related to plant mortality. At each sampling location, the proportion of samples with less than 42% crown moisture was used to predict plant mortality. Predicted mortality slightly overestimated actual mortality but differences between predicted and observed mortality were significant for only one of five sampling locations. Alfalfa growers may be able to use this simple method of crown moisture determination to prevent permanent yield reductions by initiating irrigation before substantial portions of crowns fall below the threshold moisture content of 42%.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s002710050026

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4

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Microgametophytic plastid nucleoid content and reproductive and life history traits of tribeTrifolieae (Fabaceae) (1995)

Keys, R. N. ; Smith, S. E. ; Mogensen, H. Lloyd ; [et al.]

Springer

Plant systematics and evolution 196 (1995), S. 89-98

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ISSN: 1615-6110

Keywords: Leguminosae ; Medicago ; alfalfa ; Microgametophyte ; biparental inheritance ; DAPI

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Microgametophytic plastid nucleoids were quantified for 18 species representing the four core genera of the tribeTrifolieae (Fabaceae),Medicago, Melilotus, Trigonella, andTrifolium. Generative cells of all taxa contained nucleoids, establishing that biparental plastid inheritance is common in theTrifolieae. Nucleoid number and volumes of pollen grains and generative cell nuclei differed among taxa. Nucleoid number was positively correlated with pollen grain and generative cell nuclear volumes, flower size and style length. These relationships disappeared after adjusting nucleoid number for pollen grain and generative cell nuclear volumes. Adjusted nucleoid numbers provided no evidence to support hypotheses that plastid content is associated with ploidy level, mating system, perenniality or size of the reproductive apparatus.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00985337

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5

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The zygote and proembryo of alfalfa: quantitative, three-dimensional analysis and implications for biparental plastid inheritance (1995)

Rusche, M. Losoff ; Mogensen, H. L. ; Zhu, T. ; [et al.]

Springer

Protoplasma 189 (1995), S. 88-100

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ISSN: 1615-6102

Keywords: Medicago sativa ; Plastid distribution ; Plastid inheritance ; 3-D reconstruction ; Zygote ; Embryo

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary Genetic studies have demonstrated biparental inheritance of plastids in alfalfa. The ratio of paternal to maternal plastids in the progeny varies according to the genotypes of the parents, which can be classified as strong or weak transmitters of plastids. Previous cytological investigations of generative cells and male gametes have provided no consistent explanation for plastid inheritance patterns among genotypes. However, plastids in the mature egg cells of a strong female genotype (6–4) were found to be more numerous and larger than in mature eggs of a weak female genotype (CUF-B), and the plastids in 6–4 eggs are positioned equally around the nucleus. In CUF-B, the majority of plastids are positioned below (toward the micropyle) the mid level of the nucleus, which is the future division plane of the zygote. Since only the apical portion of the zygote produces the embryo proper, plastids in the basal portion were predicted to become included in the suspensor cells and not be inherited. In the present study, we examined zygotes and a two-celled proembryo from a cross between CUF-B and a strong male genotype (301), a cross that results in over 90% of the progeny possessing paternal plastids only. Our results indicate that the distribution of plastids observed in the CUF-B egg cell is maintained through the first division of the zygote. Further, paternal plastids are similarly distributed; however, within the apical portion of the zygote and in the apical cell of the two-celled proembryo, the number of paternal plastids is typically much greater than the number of maternal plastids. These findings suggest that maternal and paternal plastid distribution within the zygote is a significant factor determining the inheritance of maternal and paternal plastids in alfalfa.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01280294

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6

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The effect of soil compaction on growth and P uptake by Trifolium subterraneum: interactions with mycorrhizal colonisation (1996)

Nadian, H. ; Smith, S. E. ; Alston, A. M. ; [et al.]

Springer

Plant and soil 182 (1996), S. 39-49

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ISSN: 1573-5036

Keywords: bulk density ; clover ; compaction ; impeded roots ; mycorrhizal growth response ; penetrometer resistance

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract The effects of vesicular-arbuscular mycorrhizal (VAM) colonisation on phosphorus (P) uptake and growth of clover (Trifolium subterraneum L.) in response to soil compaction were studied in three pot experiments. P uptake and growth of the plants decreased as the bulk density of the soil increased from 1.0 to 1.6 Mg m-3. The strongest effects of soil compaction on P uptake and plant growth were observed at the highest P application (60 mg kg-1 soil). The main observation of this study was that at low P application (15 mg kg-1 soil), P uptake and shoot dry weight of the plants colonised by Glomus intraradices were greater than those of non-mycorrhizal plants at similar levels of compaction of the soil. However, the mycorrhizal growth response decreased proportionately as soil compaction was increased. Decreased total P uptake and shoot dry weight of mycorrhizal clover in compacted soil were attributed to the reduction in the root length. Soil compaction had no significant effect on the percentage of root length colonised. However, total root length colonised was lower (6.6 m pot-1) in highly compacted soil than in slightly compacted soil (27.8 m pot-1). The oxygen content of the soil atmosphere measured shortly before the plants were harvested varied from 0.18 m3m-3 in slightly compacted soil (1.0 Mg m-3) to 0.10 m3m-3 in highly compacted soil (1.6 Mg m-3).

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00010993

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7

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Transport processes at the plant-fungus interface in mycorrhizal associations: physiological studies (1997)

Ayling, S. M. ; Smith, S. E. ; Smith, F. A. ; [et al.]

Springer

Plant and soil 196 (1997), S. 305-310

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ISSN: 1573-5036

Keywords: Allium porrum L. ; BCECF ; cytoplasmic pH ; electric potential difference ; leek ; mycorrhiza

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract The roots of most plants form symbiotic associations with mycorrhizal fungi. The net flux of nutrients, particularly phosphorus (P), from the soil into the plant is greater in mycorrhizal than in comparable non-mycorrhizal plants. However despite the widespread occurrence of mycorrhizal associations the processes controlling the transfer of solutes between the symbionts are poorly understood. To understand the mechanisms regulating the transfer of solutes information about conditions at the interface between plant and fungus is needed. Measurements of apoplastic and intracellular electrical potential difference in leek roots colonised by mycorrhizal fungi and estimates of cytosolic pH in fungal hyphae are presented. These and the implications for plant/fungal mineral nutrition in vesicular-arbuscular mycorrhizas are discussed.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1004284326231

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