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  • Angiosperms  (306)
  • calcium  (147)
  • Springer  (453)
  • American Chemical Society
  • Essen : Verl. Glückauf
  • Krefeld : Geologischer Dienst Nordhein-Westfalen
  • Oxford University Press
  • 2015-2019
  • 2005-2009
  • 1985-1989  (453)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 45 (1989), S. 175-177 
    ISSN: 1420-9071
    Keywords: Dystrophin ; calcium ; skeletal muscle ; muscular dystrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary It is suggested that in Duchenne muscular dystrophy the absence of dystrophin, which is probably a cytoskeletal protein underlying the sarcolemma, causes changes in stretch-activated cation channels rather than direct mechanical tearing of the surface membrane.
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  • 2
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    Cellular and molecular life sciences 45 (1989), S. 305-306 
    ISSN: 1420-9071
    Keywords: Baboon ; 133xenon ; cerebral blood flow ; cerebrovascular resistance ; autoregulation ; nimodipine ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In normal baboons cerebrovascular resistance changed along with blood pressure to maintain blood flow constant. This ‘autoregulation’ was not significantly altered in animals treated with a dose of the calcium channel blocker nimodipine causing selective cerebral vasodilation.
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  • 3
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    Cellular and molecular life sciences 45 (1989), S. 377-378 
    ISSN: 1420-9071
    Keywords: Chromatoid body ; spermatids ; calcium ; microtubules ; morphology ; pyroantimonate ; rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Morphological evidence for probable Ca2+ storage in the vesicular elements of the rat spermatid chromatoid body is documented using the K-pyroantimonate method, combined with EDTA chelation. Some vesicles are related to the microtubules associated with the chromatoid body. A possible involvement of Ca2+ in the intracellular movement and/or structural integrity of the chromatoid body is discussed.
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  • 4
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    Mycopathologia 108 (1989), S. 47-54 
    ISSN: 1573-0832
    Keywords: Candida albicans ; dimorphism ; yeast-mycelium transition ; calcium ; calmodulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A yeast-mycelium (Y-M) transition of Candida albicans (3153A) was induced by 1.5 mM CaCl2 · 2H2O in defined liquid medium, pH 7, at 25 °C. Germ tube formation was detected after approximately 8 h and peaks of maximum germination occurred at approximately 20 h in all experimental treatments. Non-toxic concentrations of the calmodulin inhibitor R24571 almost completely suppressed germ tube formation whereas trifluoperazine (TFP) and the Ca2+ ionophore A23187 were only about half as effective. Further Ca2+ addition failed to reverse the inhibitory effect of R24571 and induced only about 10% of the cells inhibited by TFP or A23187 to germinate.
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  • 5
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    Molecular and cellular biochemistry 89 (1989), S. 103-108 
    ISSN: 1573-4919
    Keywords: heart ; relaxation ; calcium ; sodium-calcium exchange
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Transsarcolemmal calcium movements are closely related to force generation in the heart. It is important to understand the transport pathways that control these movements of calcium across the sarcolemmal membrane. In the normal, beating heart, sodium-calcium exchange appears to be an important mechanism for the extrusion of calcium from the cell. The kinetics of this exchange are dependent upon the characteristics of the cell action potential. Calcium efflux via sodium-calcium exchange may be sufficient to balance calcium entry through calcium channels during the action potential.
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  • 6
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    Molecular and cellular biochemistry 89 (1989), S. 97-102 
    ISSN: 1573-4919
    Keywords: calcium ; sodium ; fura-2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Membrane currents and changes in intracellular calcium ion concentration ([Ca2+]i) have been recorded that can be attributed to the operation of an electrogenic, voltage-dependent sodium-calcium (Na-Ca) exchanger in mammalian heart cells. Single guinea-pig ventricular myocytes under voltage clamp were perfused internally with the fluorescent Ca2+-indicator, fura-2, and changes in [Ca2+]i and membrane current that resulted from Na-Ca exchange were isolated through the use of various organic channel blockers (verapamil, TTX), impermeant ions (Cs+, Ni2+), and inhibitors of sarcoplasmic reticulum (ryanodine). The I-V relation of Na-Ca exchange was obtained from the Ni2+-sensitive current elicited by ramp repolarization from +90 mV to −80 mV. Ramps were sufficiently rapid that little change in [Ca2+]i occured during the ramp. The (constant) [Ca2+]i during the ramp was varied over the range 100 nM to 1000 nM by varying the amplitude and duration of a pre-pulse to the ramp. The reversal potential of the Ni2+-sensitive ramp current varied linearly with 1n([Ca2+])i. The I-V relations at different [Ca2+]i over the range −60 mV to +140 mV were in reasonable accord with the predictions of a simple, simultaneous scheme of Na-Ca exchange, on the basis that only [Ca2+]i had changed. The relationship between [Ca2+]i and current at a constant membrane voltage was also in accord with this scheme. We suggest that Ca2+-fluxes through the exchanger during the cardiac action potential can be understood quantitatively by considering the binding of Ca2+ to the exchanger during the [Ca2+]i-transient and the effects of membrane voltage on the exchanger.
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  • 7
    ISSN: 1573-4919
    Keywords: calcium ; heart ; sarcoplasmic reticulum ; excitation-contraction coupling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Recent studies correlating the calcium current with, respectively, the clamp-imposed voltage and the calcium current in intact isolated mammalian cardiac myocytes are reviewed. The major findings are the following: [1] With the exception of one group, all investigators agree that a calcium transient is never observed in the absence of a calcium current. In addition, there is a good correlation between voltage dependence of the calcium current and that of the calcium transient, although this correlation may vary among the cardiac tissues from different animal species. [2] Repolarization clamp pulses from highly positive potentials produce a ‘tail current’ which is associated with a ‘tail calcium transient’. [3] The calcium transient is inhibited when the calcium current is blocked by calcium deprivation or substitution, or by the addition of calcium current antagonists, despite the fact that sarcoplasmic reticulum still contains calcium that can be released by caffeine (with inhibition of this release by ryanodine). These three findings are strongly in favor of a calcium-induced release of calcium and against the hypothesis of charge-movement-coupled release of calcium from the sarcoplasmic reticulum. [4] The only finding that would be more in favor of the latter hypothesis (although till reconciliable with the former) is that repolarization occurring before the rapid rise of calcium transient is complete curtails the calcium transient. Thus, the possibility that charge movement might somehow regulate calcium-induced release of calcium cannot be excluded.
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  • 8
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    Molecular and cellular biochemistry 89 (1989), S. 169-173 
    ISSN: 1573-4919
    Keywords: pH ; calcium ; heart muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The contractile response to acidosis is the final product of a number of different changes in the excitation-contraction coupling pathway: (i) Cai increases and subsequently decreases during acidosis; (ii) the action potential becomes longer; (iii) the sensitivity of the contractile proteins to Ca2+ decreases. The increase of Cai and the lengthening of the action potential may help to maintain contractile function, although this advantage may be offset if spontaneous Ca2− release from the s.r. occurs, secondary to the increase of Cai. The recovery of force shown in figure 1 occurs at a time when the calcium transient is decreasing, and therefore represents an increasing sensitivity of the contractile proteins to Cai, probably due to a recovery of intracellular pH(6), although it is also possible that a disappearance of spontaneous Ca2+ releases from the s.r. may be contributing [2].
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  • 9
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    Molecular and cellular biochemistry 89 (1989), S. 127-133 
    ISSN: 1573-4919
    Keywords: mitochondria ; sarcoplasmic reticulum ; calcium ; myocytes ; caffeine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The possible contribution of mitochondrial Ca2+ accumulation and release to contractile phenomena has been investigated. Two intracellular fractions of Ca2+ sequestration can be identified in cardiac myocytes, one ascribed to mitochondria. Two modes of Ca2+ transport exist within the mitochondrial fraction, one dependent upon mitochondrial respiration and the other upon extramitochondrial [Na+]. Experiments with trabeculae show that under appropriate conditions, the rate of relaxation and the amount of tension developed is dependent on these two modes of Ca2+ transport. A model is presented quantifying the contribution of the mitochondria to relaxation.
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  • 10
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    Molecular and cellular biochemistry 89 (1989), S. 109-113 
    ISSN: 1573-4919
    Keywords: heart muscle ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The role of Ca2+ in the initiation and maintenance of contraction has been extensively studies. Many of these studies have focused on how Ca2+ influx and efflux affect cytoplasmic Ca2+ (Cai) and, therefore, contraction in cardiac muscle. However, it has recently become apparent that Cai itself may play a major role in the control of Ca2+ influx and efflux from cardiac muscle. Here we review current ideas on the mechanisms underlying Ca2+ homeostasis in cardiac muscle, with specific attention to how Cai may control Ca2+ influx, both under normal and pathological conditions.
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  • 11
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    Molecular and cellular biochemistry 90 (1989), S. 155-164 
    ISSN: 1573-4919
    Keywords: polyvanadate ; mitochondria ; calcium ; pyruvate dehydrogenase ; receptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary Mitochondria isolated from the livers of rats administered with sodium meta-, ortho-, or polyvanadate, but not vanadyl sulphate, exhibited enhanced Ca2+ — stimulated respiration and uptake of calcium. These effects were shown also by mitochondria isolated from livers perfused with polyvanadate. The concentration of acid-soluble calcium decreased significantly in the mitochondrial fraction on vanadate treatment, while that in the cytosol showed a corresponding increase. Phenoxybenzamine, an antagonist to a-adrenergic receptors, effectively inhibited vanadate-induced Ca2+ mobilization, but surgical sympathectomy was without effect. This is the first demonstration of vanadate mimicking α-adrenergic agonists in vivo.
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  • 12
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    Bioscience reports 9 (1989), S. 99-109 
    ISSN: 1573-4935
    Keywords: mast cells ; exocytosis ; G-protein ; GE ; calcium ; ATP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract ATP is not required for exocytosis from permeabilised mast cells, and therefore there is no direct role for protein phosphorylation in the late stages of the activation pathway. We have measured the timecourse of exocytosis from permeabilised cells triggered to release hexosaminidase following addition of Ca2+ to cells equilibrated for 2 min with GTP-γ-S. If ATP is included at the time of permeabilisation, then exocytosis commences after a delay, the duration of which depends on the square root of the product [Ca2+][GTP-γ-S], and which may extend to beyond 3 min. When ATP is excluded then the maximal rate of exocytosis is established within 3 secs of completing the effector combination. These results suggest that the achievement of a new steady-state, induced by Ca2+ and GTP-γ-S, and required for exocytosis is inhibited by ATP. From this we conclude that dephosphorylation of an unknown regulator protein may comprise a step in the exocytotic pathway.
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  • 13
    ISSN: 1573-4935
    Keywords: secretion ; exocytosis ; chromaffin cell ; calcium ; bradykinin ; angiotensin II, muscarinic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Bradykinin, angiotensin II and a mascarnic agonist, acetyl-B-methacholine (methacholine) were all found to elict catecholamine release from cultured bovine adrenal chromaffin cells. Bradykinin was the most potent of these secretagogues and methacholine the weakest, with angiotenin II intermediate in efficacy. All three secretagogues were much less effective than nicotinic stimulation. The three secretagogues all produced a rise in cytoplasmic free calcium concentration ([Ca2+]i), measured with the fluorescent indicator fura2, which was partially independent of external calcium. In the case of bradykinin the full rise in ([Ca2+]i) may involve a component of calcium entry in addition to release of calcium from an internal store. Secretion was also found to be partially independent of external calcium. The different efficacies of the three secretagogues in elicting secretion were correlated with the rise in ([Ca2+]i) produced. The differeing efficacies of the three secretagogues may be due to the extent of release of calcium from an intracellular store which itself is less effective in eliciting secretion than a rise in [Ca2+]i following calcium entry due to nicotine. Bradykinin also stimulates calcium entry, and this may increase the efficacy of the initial rise in [Ca2+]i. Treatment with pertussis toxin resulted in an enhancement of secretion in response to all of the secretagogues.
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  • 14
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    The journal of membrane biology 107 (1989), S. 179-188 
    ISSN: 1432-1424
    Keywords: stretch-activated channel ; calcium ; oocyte ; development ; patch clamp ; tunicate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Cell-attached patch clamp recordings from unfertilized oocytes of the ascidianBoltenia villosa reveal an ion channel which is activated by mechanical deformation of the membrane. These channels are seen when suction is applied to the patch pipette, but not in the absence of suction or during voltage steps. The estimated density of these stretch-activated channels is about 1.5/μm2, a figure equal to or greater than the density of known voltage-dependent channels in the oocyte. Ion substitution experiments done with combined whole-cell and attached patch recording, so absolute potentials are known, indicate that the channel passes Na+, Ca2+ and K+, but not Cl−. The channel has at least two open and two closed states, with the rate constant that leaves the longer-lived closed state being the primary site of stretch sensitivity. External Ca2+ concentration affects channel kinetics: at low calcium levels, long openings predominate, whereas at high calcium virtually all openings are to the short-lived open state. In multiple channel patches, the response to a step change in suction is highly phasic, with channel open probability decreasing over several hundred milliseconds to a nonzero steady-state level after an initial rapid increase. This channel may play a role in the physiological response of cells of the early embryo to the membrane strains associated with morphogenetic events.
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  • 15
    ISSN: 1432-1424
    Keywords: calcium ; calmodulin ; absorption ; ileum ; brush-border vesicle ; phosphorylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary In rabbit ileum, Ca2+/calmodulin (CaM) appears to be involved in physiologically inhibiting the linked NaCl absorptive process, since inhibitors of Ca2+/CaM stimulate linked Na+ and Cl− absorption. The role of Ca2+/CaM-dependent phosphorylation in regulation of the brush-border Na+/H+ antiporter, which is believed to be part of the neutral linked NaCl absorptive process, was studied using purified brush-border membrane vesicles, which contain both the Na+/H+ antiporter and Ca2+/CaM-dependent protein kinase(s) and its phosphoprotein substrates. Rabbit ileal villus cell brush-border membrane vesicles were prepared by Mg precipitation and depleted of ATP. Using a freezethaw technique, the ATP-depleted vesicles were loaded with Ca2+, CaM, ATP and an ATP-regenerating system consisting of creatine kinase and creatine phosphate. The combination of Ca2+/CaM and ATP inhibited Na+/H+ exchange by 45±13%. This effect was specific since Ca2+/CaM and ATP did not alter diffusive Na+ uptake, Na+-dependent glucose entry, or Na+ or glucose equilibrium volumes. The inhibition of the Na+/H+ exchanger by Ca2+/CaM/ATP was due to an effect on theV max and not on theK m for Na+. In the presence of CaM and ATP, Ca2+ caused a concentration-dependent inhibition of Na+ uptake, with an effect 50% of maximum occurring at 120nm. This Ca2+ concentration dependence was similar to the Ca2+ concentration dependence of Ca2+/CaM-dependent phosphorylation of specific proteins in the vesicles. The Ca2+/CaM/ATP-inhibition of Na+/H+ exchange was reversed by W13, a Ca2+/CaM antagonist, but not by a hydrophobic control, W12, or by H-7, a protein kinase C antagonist. we conclude that Ca2+, acting through CaM, regulates ileal brush-border Na+/H+ exchange, and that this may be involved in the regulation of neutral linked NaCl absorption.
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  • 16
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    The journal of membrane biology 110 (1989), S. 49-55 
    ISSN: 1432-1424
    Keywords: loop of Henle ; potassium secretion ; channels ; acid/base balance ; thick ascending limb ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Ca2+-activated K+ channels were studied in cultured medullary thick ascending limb cells (MTAL) using the patch-clamp technique. The purpose was to determine the effect of acidic pH on channel properties in excised patches of apical cell membrane. At pH 7.4, increasing Ca2+ on the intracellular side or applying positive voltages increases channel open probability. Reducing pH to 5.8 on the intracellular face of the channel decreases channel open probability at each voltage and Ca2+ concentration. Channel mean open times display two distributions and mean closed times display three distributions. Increasing Ca2+ or applying depolarizing voltages lengthens each of the mean open times and shortens each of the closed times. Lowering pH to 5.8 decreases the mean open times and increases mean closed times at each Ca2+ and voltage with the greatest effect on the mean closed times. In contrast, both single-channel conductance and channel kinetics are unaffected when pH is reduced to 5.8 on the extracellular face of the membrane. We conclude that protons interfere with Ca2+ binding to the gate of Ca2+-activated K+ channels reducing the probability of channel opening.
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  • 17
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    The journal of membrane biology 110 (1989), S. 19-28 
    ISSN: 1432-1424
    Keywords: colon ; ion transport ; ion channel ; cyclic nucleotides ; calcium ; potassium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Using patch-clamp techniques, we have studied Ca2+-activated K+ channels in the basolateral membrane of freshly isolated epithelial cells from rabbit distal colon. Epithelial cell clusters were obtained from distal colon by gentle mechanical disruption of isolated crypts. Gigaohm seals were obtained on the basolateral surface of the cell clusters. At the resting potential (approximately −45 mV), with NaCl Ringer's bathing the cell, the predominant channels had a conductance of 131±25 pS. Channel activity depended on voltage as depolarization of the membrane increased the open probability. In excised inside-out patches, channels were found to be selective for K+ over Na+. Channel activity correlated directly with bath Ca2+ concentration in the excised patches. Channel currents were blocked by 5mm TEA+ and 1mm Ba2+. In cell-attached patches, after addition of the Ca2+ ionophore A23187, which increases intracellular Ca2+, open probability was markedly increased. Channel activity was also regulated by cAMP as addition of 1mm dibutyryl-cAMP in the bath solution in cell-attached patches increased channel open probability over 20-fold. Channels that had been activated by cAMP were further activated by Ca2+. We conclude that the basolateral membrane of epithelial cells from descending colon contains a class of potassium channels, which are regulated by intracellular Ca2+ and cAMP.
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  • 18
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    Plant systematics and evolution 162 (1989), S. 213-229 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Fagaceae ; Cuticles ; Recent ; Tertiary ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A systematic reassessment of megafossil records ofFagaceae in Central Europe has been undertaken on the basis of leaf cuticular characters. The oldest representatives date back to the Eocene:Quercus subhercynica spec. nova,Dryophyllum furcinerve (Rossm.)Schmalh.,Trigonobalanopsis rhamnoides (Rossm.) gen. & comb. nov. In the Oligocene other members of extant genera appear:Quercus rhenana (Weyl. & Kilpp.)Knobloch & Kvaček,Fagus attenuata Goepp.,Lithocarpus saxonicus spec. nova. In the Neogene these ancient taxa (except inFagus lineage), are gradually replaced by deciduous species ofQuercus andCastanea. Trigonobalanus andCastanopsis are recorded by fruits (or wood) only.
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  • 19
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    Plant systematics and evolution 162 (1989), S. 165-191 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Chloranthaceae ; Platanaceae ; Trochodendrales ; Fagaceae ; Cercidiphyllum ; Paleobotany ; phylogeny ; floral structure ; leaf architecture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Paleobotanical studies indicate that several isolated and systematically depauperate groups of extant woody dicotyledons originated in the Mid Cretaceous. TheChloranthaceae had probably differentiated into insect-pollinated (Chloranthus andSarcandra) and wind-pollinated (Ascarina andHedyosmum) forms by the end of the Albian, and leaves referable to theTrochodendrales are known from the Albian and Cenomanian. In the latest Cretaceous and Early Tertiary, extinct representatives of theTrochodendrales includedNordenskioldia and theJoffrea-Nyssidium complex. ThePlatanaceae also differentiated before the end of the Albian and initially had insect-pollinated, unisexual flowers with five carpels or stamens. Some of these features persisted in the platanoid lineage until the Early Tertiary, and during the Paleocene and Eocene thePlatanaceae included forms with elliptical, palmate and pinnate foliage. The history of thePlatanaceae suggests that several features of the reproductive morphology of extant taxa may have arisen in association with a trend toward wind pollination. In the Mid Cretaceous, platanoid foliage partially intergrades with pinnateSapindopsis and pedateDebeya-Dewalquea leaves suggesting a close relationship betweenPlatanaceae andRosidae andFagaceae respectively. TheChloranthaceae, Trochodendrales, andPlatanaceae all occupy a somewhat intermediate position between theMagnoliidae andHamamelidae and are of considerable interest with respect to their role in the initial radiation of nonmagnoliid (“higher”) dicotyledons.
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  • 20
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    Plant systematics and evolution 162 (1989), S. 193-211 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Hamamelididae ; Trochodendrales ; Hamamelidales ; Hamamelidaceae ; Hamamelideae ; fossilHamamelidaceae ; Floral structure ; fruit ; seed ; valvate anther dehiscence ; Floral evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract New investigations on the flower and fruit structure of extantHamamelidaceae and other LowerHamamelididae together with new finds of fossil flowers and seeds from the Upper and Lower Cretaceous provide the outline of an increasingly more differentiated picture of the early evolution of the subclass. Three patterns of valvate anther dehiscence are recognized in the subfamilyHamamelidoideae (and the subclassHamamelididae). The basic (plesiomorphic) type within theHamamelididae has 2 valves per theca. The type with 1 valve but 2 pollen sacs per theca is both consistent and exclusive for the 5 southern genera of theHamamelidaceae. They seem to be the remnants of a homogeneous group that originated before the Upper Cretaceous. This is supported by fossil hamamelidaceous flowers from the Upper Cretaceous that have thecae with 1 valve. Since several-seededHamamelidaceae predate one-seeded forms in the fossil seed record (in Europe) and the systematic structure of the one-seeded group is relatively more homogeneous, several-seeded groups are considered to be more ancient. Several parallel evolutionary trends are recognized within theHamamelidaceae as well as within the LowerHamamelididae: anther dehiscence with 2 valves per theca → 1 slit or 1 valve; pollen sacs per theca 2 → 1; pollen tricolpate → polyforate; exine coarsely reticulate → finely reticulate; loss of perianth (tepals or petals and sepals) and concomitant loss of fixed number of floral organs; differentiation of exposed nectaries.
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  • 21
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    Plant systematics and evolution 162 (1989), S. 231-250 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Juglandaceae ; Paleobotany ; pollen ; fruits ; evolution ; Cretaceous ; Tertiary
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The major radiation of theJuglandaceae occurred during the early Tertiary as recorded by the proliferation of juglandaceous pollen and the appearance of fruits representing extinct and extant genera of the family. Juglandaceous pollen types of the Paleocene were predominantly triporate and exhibited a greater diversity in patterns of exinous thinning than occurs in the family today. Analyses of in situ pollen from early Tertiary juglandaceous inflorescences confirms the taxonomic value of certain patterns of exinous thinning. Data from co-occurring fruits and pollen indicate that relatively unspecialized, isopolar triporate pollen of the type presently confined to the tribeEngelhardieae also occurred in other tribes of the family during the Paleocene. Pollination has been mostly anemophilous throughout the Tertiary. Both wind and animal fruit-dispersal syndromes were established early in the radiation of the family but a greater diversity of wind-dispersed genera has prevailed.
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  • 22
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    Plant systematics and evolution 162 (1989), S. 251-265 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Rutaceae ; Phylogeny ; fructifications ; morphology ; anatomy ; paleogeography ; Cretaceous ; Tertiary
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A comparative analysis of the seed morphology and anatomy of fossil and extantRutaceae (mainlyZanthoxyleae andToddalioideae) is presented. This allows to place the most important fossil taxa in a time-table and on paleogeographical maps. A phylogenetic scheme demonstrates the postulated historical relationships ofEvodia, Zanthoxylum, Fagara, Rutaspermum, Acronychia, Toddalia, Fagaropsis, andPhellodendron.
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  • 23
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    Plant systematics and evolution 162 (1989), S. 267-283 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Buxaceae ; Buxus ; Pollen morphology ; leaf venation ; fossil records ; systematics ; evolution ; chorogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Trends of pollen grain aperture evolution and exine characters as well as characters of leaf venation, petiole and axial vascularization are briefly described and related to geographical distribution and classification ofBuxus. A review of fossil records is given. Three major taxonomic groups can be delimitated within the genus, and aspects of their relationships and chorogenesis are presented. The level of differentiation, the pattern of distribution and the fossil record speak in favour of an ancient origin of the genus.
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  • 24
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    Plant systematics and evolution 165 (1989), S. 227-237 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Eucalyptus ; Eudesmieae ; Floral morphology ; calyx ; corolla ; operculum ; growth ; allometry ; convergence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In theEudesmieae B eucalypts and inEucalyptus caesia, the perianth of the mature flower consists of a single, anatomically continuous, opercular structure that is crowned by the tips of the original free and separate calycine and corolline whorls. Ontogenetic and comparative evidence supports the hypothesis that this operculum is mostly corolline in composition, and that the calycine parts have been elevated distally onto the dorsal surface. In theEudesmieae B eucalypts this condition appears to be due to precocious initiation of the corolline primordia, followed by expansion and continuity of their growth centres which incorporates the areas at or below the base of the still differentiating calycine whorl. InEucalyptus caesia the corolline primordia are not precocious, but a similar situation is effected by a seemingly retarded increase in receptacle diameter relative to lateral expansion of the corolline growth centre(s). In these two examples the same final perianth form apparently derives from two different sets of growth processes which, nonetheless, result in the same allometric relationships within the developing flower. Although identical at maturity, the operculum form in these two taxa is best described in terms of convergence, rather than homology.
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    Plant systematics and evolution 166 (1989), S. 41-44 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Araceae ; Arum spp. ; Pollen types ; pollination
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    Notes: Abstract In a second paper onArum pollen seven further taxa are investigated. Most of them have spinose pollen, only inA. korolkowii the pollen is scabrose. The possible relation between pollen sculpturing and the actual pollination mode is discussed.
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    Plant systematics and evolution 166 (1989), S. 11-30 
    ISSN: 1615-6110
    Keywords: Angiosperms ; monocotyledons ; Amaryllidaceae ; Eucharis ; Phenetics ; chromosome morphology ; isozyme electrophoresis ; speciation ; sibling species
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    Notes: Abstract Eucharis candida andE. formosa are two often sympatric species of bulbous geophytes restricted to neotropical rain forest understory. The species are most common in eastern Ecuador, and are the only two east Ecuadorean species of the genus found north of the Pastaza valley. Data from phenetic, karyotypic, and preliminary isozyme electrophoretic analyses of both species are represented. The species are distinguishable phenetically and karyologically, but isozyme-based relationships are more complex. Phenetic resolution of the isozyme phenotypes supports recognition of two species in Ecuador. A Peruvian isolate ofE. formosa, though not morphologically distinct, shows both allozyme and chromosomal divergence from Ecuadorean populations. Cladistic relationships based on overall allozyme data do not support species distinction, but a novel electrophoretic phenotype for glutathione reductase is shared only by individuals ofE. candida. An apparent geographic component within the monophyletic groups resolved in the cladogram suggests that some degree of gene flow between these two species has been maintained without the complete loss of morpholgoical species identity. This may have been mediated either by artificial population structures due to a probable long history of cultivation, or via Pleistocene refugia effects. Both species may have originated in eastern Ecuador from a common ancestral population which has since radiated outward, perhaps several times.
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    Plant systematics and evolution 166 (1989), S. 45-67 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Espeletia ; Diallel cross ; pollen donors ; parental effects ; outcrossing distance ; inbreeding ; seed abortion ; incompatibility ; pollen tube growth
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    Notes: Abstract The influence of different pollen donors on seed formation was investigated in three populations ofEspeletia schultzii that differ in environmental conditions and life history characteristics. Self pollen and pollen from different donors (〈 15m apart) within each population was used in a diallel design in order to test the genetic base of seed set variation. Three measures of seed formation were used: (1) achene number; (2) proportion of filled achenes (fruits) that distinguishes between achenes with seeds and empty achenes; (3) proportion of aborted seeds that distinguishes between viable and aborted seeds. Self-pollinations resulted in empty achenes. Achene number did not vary between the different pollen donors. A bimodal pattern of filled achenes was found in two populations in two consecutive years. On the other hand, a unimodal pattern was found in crosses between more distant donors (〉 30m). These patterns seems to be the results of a sporophytic incompatibility system. Seed abortion was highest at the higher elevations and seems to be correlated with elevation rather than with any genetic effect.
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    Plant systematics and evolution 166 (1989), S. 69-78 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Leguminosae ; Medicago lupulina ; M. secundiflora ; Chromosomes ; karyotypes ; chloroplast DNA evolution ; phylogeny
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    Topics: Biology
    Notes: Abstract Studies were made on the chromosome complements and chloroplast genomes ofMedicago lupulina andM. secundiflora, which comprise sectionLupularia ofMedicago. Both types of analyses indicated more substantial differences between these species than suggested by external morphology.Medicago lupulina has a relatively asymmetrical karyotype in terms of centromeric position and relative length. The karyotype ofM. secundiflora is comparatively more asymmetrical in centromeric position and reduced in absolute size but exhibits greater symmetry in relative length. The restriction endonuclease fragmentation patterns of the chloropiast DNA of these two species (with Bam HI, Eco RI, Bgl II, and Xho I) show little similarity, with only 17% of the fragments matching in size. The lack of interspecific congruence among data of morphology, karyology and cpDNA inLupularia is contrary to consistency exhibited among these data inMedicago subsect.Intertextae.
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    Plant systematics and evolution 166 (1989), S. 131-139 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Najadaceae ; Najas marina ; Isozymes ; polyploidy ; Polymorphism
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    Topics: Biology
    Notes: Abstract The genetic variability of five natural populations ofNajas marina L., i.e. one diploid of subsp.marina (Europe), two of subsp.intermedia (Europe) and both a diploid (C. Africa) and a tetraploid (Middle East) of subsp.armata, has been estimated by means of electrophoretic studies. These populations differ in their morphology and karyotype. Emphasis is placed on the characteristics and status of a tetraploid cytotype from Merkaz Sappir (Israel). Almost all the variation observed is expressed in seed alcohol dehydrogenase (ADH). The differences are in a unique allele of theAdh-2 locus and in the formation of novel heteromeric isozymes.Adh genes in seeds can be used as a marker for the autotetraploid character. The other enzyme systems tested failed in this respect. The genetic variability based on 23 loci is rather low. Nevertheless, the autotetraploid population has a higher or equal ratio of polymorphic loci than the related diploids. Cluster analysis illustrated not only thatNajas marina subsp.marina has diverged much from subsp.intermedia and subsp.armata, but also showed the difference between the latter two taxa, as well as the intermediate position of the autotetraploid population.
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    Plant systematics and evolution 166 (1989), S. 183-196 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Myrtaceae ; Eucalyptus ; E. clöeziana ; Monocalyptus ; Floral morphology ; operculum ; androecium ; staminophore ; phyllotaxy
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    Notes: Abstract Flowers ofEucalyptus clöeziana have two clearly distinct perianth whorls. The small free parts of the outer (calycine) whorl cease growth early and are lost from the flower; the parts of the inner (corolline) whorl become continuous laterally by confluence of growth centres and form an operculum in the mature flower. The stamens are inserted on a circumfloral buttress (staminophore) that is homologous to the adaxial corolline component inAngophora and the bloodwood andEudesmia eucalypts. Flowers ofMonocalyptus have only one perianth whorl, which is opercular. The stamens are similarly inserted on a circumfloral buttress. Developmental study does not provide conclusive evidence for either a calycine or corolline determination of theMonocalyptus operculum, but comparison with other eucalypt groups, includingE. clöeziana (the sister taxon), predicts an essentially corolline composition.
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    Plant systematics and evolution 166 (1989), S. 211-223 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Triticeae ; Hordeum brachyantherum ; H. californicum ; H. capense ; H. secalinum ; Morphometrics ; cluster analysis ; classificatory discriminant analysis ; canonical analysis ; sheared principal component analysis ; bootstrap validation ; identification key
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    Notes: Abstract Field collections and 296 herbarium sheets were examined for 27 morphometric variables. A priori species identifcation was based on geographical distribution except forH. californicum, a diploid species primarily occurring in California and differing from the much more widespread tetraploidH. brachyantherum that thrives in N. America and N.E. Asia;H. capense grows in S. Africa andH. secalinum mainly in Europe. Various cluster analyses were used followed by cluster recovery verification. Classificatory discriminant analysis and validation by the bootstrap yielded 85–90% overall total correct classification of the four species. Canonical analysis revealed thatH. californicum occupies an intermediate phenetic position among the other three distinct species. Factors of shape differences were unravelled and portrayed by shearing. A revised key to species was drawn up.
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    Plant systematics and evolution 166 (1989), S. 225-241 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Geraniaceae ; Geranium caespitosum ; Breeding system ; ecotype ; gynodioecy ; pollen sterility ; self-fertility ; selfing ; inbreeding depression ; stigma receptivity
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    Notes: Abstract Characters that have the potential to alter the breeding system ofGeranium caespitosum were investigated. The characters differ mechanistically, functioning either endogenously and independent of pollen transfer, or exogenously by influencing pollen transfer. Little variation in self-fertility (endogenous mechanism) was measured among populations from different elevations grown in a common garden. Variation in floral morphology (exogenous mechanism) was limited and unlikely to create a change in the breeding system. Macroscopic variation (exogenous mechanism), including gynodioecy, sexual specialization, and pollen sterility, was observed in extreme elevation populations and probably has a sizeable effect on the breeding system.
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    Plant systematics and evolution 166 (1989), S. 249-252 
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    Keywords: Angiosperms ; Primulaceae ; Cyclamen ; C. somalense ; Taxonomy ; phytogeography ; Mediterranean floristic element ; Flora of Somalia
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    Notes: Abstract Cyclamen somalense Thulin & Warfa, spec. nova, the first member of the genus known from tropical Africa, is described from the Al Miskat Mts in NE. Somalia. The new species is closely related to the E. MediterraneanC. persicum Mill. The disjunct Mediterranean element in the mountain flora of northern Somalia, to whichC. somalense belongs, is believed to be largely a relict of Tertiary origin.
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    ISSN: 1615-6110
    Keywords: Angiosperms ; Ranunculaceae ; Ranunculus cantoniensis ; R. chinensis ; R. silerifolius ; Amphidiploid ; aneuploid induction ; cytotaxonomy ; fertility ; habitat segregation ; hybrid ; multivalent ; speciation
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    Notes: Abstract Cytogenetical studies were carried out on the successive generations of offsprings from the induced tetraploid hybrid (2n = 32) betweenRanunculus silerifolius (2n = 16) andR. chinensis (2n = 16). Aneuploids, 2n = 30 to 35, frequently occurred. In latter subsequent generations the deviation of aneuploids increased, but the proportion of euploids decreased, accompanied by the reduction of fertility of pollen grains and seed sets. F2 and F4 PMCs constantly exhibited meiotic abnormality, i.e. formation of quadrivalents and univalents. The speciation process ofR. cantoniensis (2n = 32), which was presumed to arise from tetraploid hybrids between the above two species, is discussed on the basis of the above evidences.
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    Plant systematics and evolution 167 (1989), S. 137-148 
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    Keywords: Angiosperms ; Orchidaceae ; Leporella ; Formicidae ; Myrmecia ; Ant pollination pseudocopulation ; floral morphology
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    Notes: Abstract Leporella fimbriata is a self compatible orchid of southern Australia. It is dependant across its range on unique pollination by sexually attracted male winged antsMyrmecia urens, which pseudocopulate with the flower. Typical pollination sequences began with an initial circling then zig-zag flight to the flower. Vectors usually alighted on the inflorescence stem and quickly crawled to the flower where they adopted a copulatory position sideways along the wide labellum, pseudocopulatory probing immediately followed. In this position pollen carried on the thorax was deposited on the stigma. Departure from the labellum usually resulted in pollinium removal. Pollinator movements were restricted and the distribution leptokurtic with a mean of 3.141 ± 4.59 m. Pollination was widespread but variable from site to site and season to season with a maximum of 70% of all flowers being pollinated. Pollinator limitation is indicated. Traits essential for this pollination interaction include the coincidence of orchid and ant geographic distributions and the coincidence of flowering with the flight period of the ant. The production of pheromonelike substances and the distinctive floral morphology are also essential for attraction and manipulation of male ants. The ant mating system which the orchid can exploit is also important.
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    Plant systematics and evolution 167 (1989), S. 189-194 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Magnoliidae ; Annonaceae ; Annona ; Rollinia ; Beetle pollination ; flower evolution
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    Notes: Abstract Dynastid scarab beetle pollination appears basic within the genusAnnona. Those species ofAnnona which are more morphologically derived, as well as allRollinia spp. possess reduced floral chambers and attract small beetles likeNitidulidae orStaphylinidae. Pollination of the primitive species ofAnnona byDynastinae would imply that the genus had not evolved before the Tertiary. The fossil record is in congruence with this hypothesis. Once again it is stressed that the cantharophilous syndrome, as it is found in theAnnonaceae, Magnoliaceae, Eupomatiaceae andCalycanthaceae, with beetles being exclusive pollinators, is a secondary and derived condition and obviously different from the expected basic entomophily of the original angiosperms.
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    Plant systematics and evolution 168 (1989), S. 49-57 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Hypochoeris ; Karyotype ; karyogram ; idiogram ; basic chromosome number ; symmetry of karyotype ; asymmetrical index
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    Notes: Abstract FiveHypochoeris spp. from Sicily have been investigated:H. glabra L. (2n=10),H. radicata L. (2n=8),H. cretensis L. (2n=6),H. laevigata L. (2n=12),H. robertia Fiori (2n=8). Basic chromosome numbers are very variable, x = 3, 4, 5, 6. The karyotype of each species is presented. Geographical origin (S. America or Mediterranean region) of the genusHypochoeris and the taxonomic position ofH. robertia are discussed.
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    Plant systematics and evolution 168 (1989), S. 143-148 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Caryophyllaceae ; Silene sect.Siphonomorpha ; sect.Auriculatae ; Crossing experiments
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    Notes: Abstract Ten species in the genusSilene sectt.Siphonomorpha andAuriculatae were crossed artificially involving 612 crosses to test inter- and infraspecific, intervarietal and intersectional crossability. In sect.Siphonomorpha all interspecific crosses (between diploids) failed due to cross- or seed-incompatibility; however, intervarietal crosses betweenS. gigantea var.gigantea andS. gigantea var.incana produced hybrids. In sect.Auriculatae hybrids were produced betweenS. vallesia andS. boryi, both tetraploids, but crosses between these and the diploid species were unsuccessful. The delimitation and status of the species in both sections was supported by the crossing results.
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    Plant systematics and evolution 168 (1989), S. 159-165 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Orchidaceae ; Coryanthes ; Fragrance analyses ; 2-N-methylaminobenzaldehyde ; taxonomic studies
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    Notes: Abstract All members of the investigated genusCoryanthes (subtribeStanhopeinae) are pollinated by male euglossine bees. The different fragrance profiles are the primary reproductive isolating mechanisms, because the flowers are interfertile. The fragrance patterns of 17 species ofCoryanthes were analyzed by gas chromatography as a means to improve the classification of this genus. A first amine (2-N-methylaminobenzaldehyde) was found to be the main fragrance compound of an as yet unclassifiedCoryanthes species.
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    Plant systematics and evolution 168 (1989), S. 221-225 
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    Keywords: Angiosperms ; monocotyledons ; Araceae ; Pothos sect.Allopothos ; Pothos crassipedunculatus ; spec. nova ; Taxonomy ; systematics ; Flora of India
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    Notes: Abstract Pothos crassipedunculatus Sivadasan & Mohanan (Araceae), a new species closely related to the SW. Indian endemic and little known speciesP. thomsonianus Schott is described. It is characterized by the the non-ligulate, shortly vaginate petiole, thickly peduncled inflorescence, broadly ovate spathe and a sessile spadix. It is included in ser.Brevivaginati Engler of sect.Allopothos Schott.
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    Plant systematics and evolution 168 (1989), S. 123-141 
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    Keywords: Angiosperms ; Liliiflorae ; Liliales ; Dioscoreales ; Asparagales ; Cladistics ; relationships ; taxonomy
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    Notes: Abstract Comparisons between previous intuitive or phenetic classifications of the netveinedLiliiflorae was used to determine a suitable group of taxa for cladistic analyses. The resultant 48 genera and generic groupings comprising 19 families from within theAsparagales, Liliales andDioscoreales were then analysed. The cladistics largely supported previous treatments, with theLiliales, Dioscoreales andAsparagales all monophyletic.
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  • 42
    ISSN: 1615-6110
    Keywords: Angiosperms ; Leguminosae ; Medicago truncatula ; Medicago littoralis ; Bruchidius bimaculatus ; Bruchid infestation
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    Notes: Abstract The bean weevilBruchidius bimaculatus was found in fruits of 68 of 217 populations of theMedicago truncatula — M. littoralis complex of Israel, Greece, Italy and Spain. Infestation was higher in fruits of somewhat larger than mean size, and in the more pubescent and tightly coiled fruits. Bean weevil size proved to be independent of fruit size, so that the “preference” for larger fruits does not seem due to adaptation to a larger food source or a larger domicile. Fruit size has been used to delimit the host “species”M. truncatula andM. littoralis, but the character proved to be unimodal, and it is apparent that the taxonomy of the plant complex requires further clarification. Of the 11 472 fruits examined, less than 4% were infested. Given that the plants have evolved indehiscent legumes in which typically only one of the approximately six seeds survives to reproduce, and that very few seeds of a fruit are destroyed, the bruchid's infestation appears to be non-harmful, and indeed the association may be mutualistic.
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    Plant systematics and evolution 163 (1989), S. 53-69 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Liliaceae ; Lilium ; C-banding ; heterochromatin ; karyosystematics ; karyotype
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    Notes: Abstract C-band patterns are described for 20Lilium spp. distributed across six sections. All species have a similar basic karyotype (n = 12) but C-bands differ markedly between them. The patterns are characterized by a dispersed scattering of thin intercalary bands as well as centric and NOR bands. Only one species,L. canadense, shows a clear equilocal pattern with intercalary C-bands occurring proximally in all of the longer chromosome arms. Comparing species, similar patterns are revealed forL. regale andL. sulphureum, forL. formosanum andL. longiflorum (all in sect.Leucolirion) and to a lesser extent forL. hansonii, L. martagon, andL. tsingtauense (sect.Martagon). The pattern forL. henryi (previously classed in sect.Sinomartagon) matches those ofL. regale andL. sulphureum quite well and its transfer to sect.Leucolirion is proposed. This is consistent with results from interspecies hybrids betweenL. henryi andL. regale (and related species) which are reportedly fertile. No other clear similarities in C-band patterns were seen across species. It seems that C-band patterns change rapidly inLilium and hence their usefulness in classification will be restricted to identifying closely related species.
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    Plant systematics and evolution 163 (1989), S. 81-85 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Ranunculaceae ; Anemone ; Pulsatilla ; Hepatica ; Chloroplast DNA ; restriction endonuclease analysis
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    Notes: Abstract Chloroplast DNA of seven species belonging toAnemone (sectt.Omalocarpus, Anemonidium, andAnemonanthea),Hepatica, andPulsatilla have been analyzed by restriction enzymes. According to the dendrogram constructed, the sections ofAnemone and the generaHepatica andPulsatilla seem to be evolutionary approximately equidistant to each others. This supports the concept that these groups should be treated on a similar taxonomic level, either as genera or subgenera.
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    Plant systematics and evolution 163 (1989), S. 87-92 
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    Keywords: Angiosperms ; Alliaceae ; Allium ; B-chromosomes ; nucleolar activity
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    Notes: Abstract Nucleolar activity was analyzed in two samples of plants of the wild onion speciesAllium cernuum, one from Canada (2n=14) and one from the United States of America (2n=14+3B), using phase contrast analysis and C- and Ag-NOR-banding. Three chromosome pairs of the standard A-chromosome complement show small telomeric satellites, which corresponds to the maximum number of Ag-NOR-bands at metaphase and to the telomeric C-heterochromatin. However, the maximum number of nucleoli observed at interphase was eight, indicating that another chromosome pair possesses nucleolar activity. Corresponding results were obtained for the A-chromosome complement of plants from the United States of America, however, these plants further possess three small metacentric supernumerary chromosomes, which show telomeric satellites on both arms, corresponding to two telomeric Ag-NOR-bands observed after silver staining. The presented data clearly indicate that the B-chromosomes ofAllium cernuum possess rDNA gene clusters which show strong nucleolar activity.
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    Plant systematics and evolution 163 (1989), S. 93-105 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Leguminosae (Fabaceae) ; Caesalpinioideae (Caesalpiniaceae) ; Cassia ; Chamaecrista ; Senna ; Stigma morphology ; taxonomy ; floral ecology
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    Notes: Abstract Two stigma forms occur inChamaecrista andSenna, but only one inCassia. In the common chambered form, a stigma pore is positioned on the reflexed style tip and is the entrance to a tapering chamber. The pore rim is fringed by hairs which vary in number, size, distribution and shape. In the alternative form the stigma is situated at the apex of the curved style and is crateriform. The crater rim is fringed by hairs of variable number and shape. The stigmatic hairs are predominantly unicellular and cutinized. Stigma and hair differences aid in the taxonomy of the genera. Their functions in pollination biology are discussed.
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    ISSN: 1615-6110
    Keywords: Angiosperms ; Orchidaceae ; Orchis ; Dactylorhiza ; Gymnadenia ; Taxonomy ; interspecific relationship ; enzyme electrophoresis ; computer evaluation
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    Notes: Abstract Ten species of orchid plants belonging to the generaOrchis (7),Dactylorhiza (2), andGymnadenia (1) were analyzed by enzyme electrophoresis. Each species can be identified by a combination of enzyme bands different from those of all other species examined. The electrophoretic data were used for the construction of phenetic and phylogenetic trees with the help of computer programs. The trees were almost identical regardless which method was used. Our results differ considerably from a classification based on morphological evidence. The electrophoretic data indicate that the genusOrchis is not a monophyletic group.
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    Plant systematics and evolution 163 (1989), S. 121-125 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Acanthaceae ; Justicia sect.Ansellia ; J. brevipedunculata ; spec. nova ; Flora of Tropical East Africa
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    Topics: Biology
    Notes: Abstract Justicia brevipedunculata, a new species ofJ. sect.Ansellia endemic to Tanzania, is described and illustrated. Detailed palynological information is given, and relationships to other species of the section are discussed.
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    Plant systematics and evolution 163 (1989), S. 127-131 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Portulacaceae ; Grahamia bracteata ; Chromosome number ; karyotype ; base number
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    Notes: Abstract The somatic and gametic chromosomes of the monotypical genusGrahamia (G. bracteata) have been studied for the first time: 2n = 18, n = 9. The karyotype is symmetrical; of the nine m pairs one has microsatellites. The basic chromosome number x = 9 is considered to be primitive within the family.
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    Plant systematics and evolution 163 (1989), S. 147-152 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Beilschmiedia ; Calluna ; Polyalthia ; Strelitzia ; Acetolysis ; palynology ; sporoderm ; exine ; intine ; pollen characters
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    Topics: Biology
    Notes: Abstract The acetolysis method intreduced byGunnar Erdtman is still a very welcome and highly successful technique in palynology. However, acetolysis destroys all pollen material with the exception of sporopollenin that forms the outer pollen wall, the exine. Modern palynology in its application to plant systematics and phylogeny must consider all sporoderm characters, not only those of the exine. The neglect of the intine may distort some principal palynological aspects. This is illustrated by cases of total breakdown or gross modification of thin exine structures (e.g. inBeilschmiedia, Strelitzia) and by the clarification of apertures (e.g.,Polyalthia, Fissistigma, Calluna). In our view the investigation of both acetolysed and non-acetolysed pollen is obligatory for a well balanced view of pollen structure and function.
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    Plant systematics and evolution 163 (1989), S. 133-146 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Cucurbitaceae ; Cucumis ; C. sativus ; C. melo ; C. metuliferus ; C. anguria ; C. zeyheri ; C. myriocarpus subsp.leptodermis ; comb. nov. ; Crossing experiments ; meiosis of hybrids ; polyploidy ; isozymes ; DNA analysis ; evolution
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    Notes: Abstract Meiosis in seven interspecificCucumis hybrids has been analysed i.a. inC. metuliferus ×C. zeyheri, where the parents belong to different sections. In the triploid hybrids a remarkably high number of trivalents has been found. Additional data from literature on geographical distribution, cucurbitacins, flavonoid patterns, isozymes, C-banding, genome size, DNA amount and chloroplast DNA are used to discuss species relationships and evolution. The African cross-compatible group is divided into theMyriocarpus subgroup with the diploid speciesC. africanus, C. myriocarpus subsp.leptodermis and subsp.myriocarpus, and theAnguria subgroup withC. anguria, C. dipsaceus, C. ficifolius, C. prophetarum, C. zeyheri and all polyploids (exceptC. heptadactylus). It is argued that the Asian subg.Melo with x = 7 is derived from the African subg.Cucumis with x = 12; the latter contains all the polyploid species and has the most common basic chromosome number of theCucurbitaceae. This phylogenetic advance is interpreted with concepts of the quantum model of evolution.
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  • 52
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Taraxacum ; Agamospermy ; NOR-chromosome ; chromosomal rearrangement ; transposable genetic elements
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    Topics: Biology
    Notes: Abstract Morphological variation for the NOR chromosome was studied for four half-siblings of a sexual outbreedingTaraxacum, for three siblings of the obligate agamospermT. pseudohamatum, and for two individuals of the agamospermT. brachyglossum. No rearrangement was detected for the 113 chromosomes of sexuals, or for 41 chromosomes of two agamospermous individuals. In the other three agamospermous individuals, 3/16, 5/50, and 5/20 chromosomes showed evidence of chromosomal rearrangement. The majority of rearrangement events (10/13) occurred to the satellite rather than to the body of the NOR-chromosome. It is considered that such high levels of somatic chromosomal rearrangement in agamospermousTaraxacum may be the result of activity by transposable genetic elements. This recombination may be of selective advantage to asexual plants which cannot generate genetic variability through the sexual process.
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    Plant systematics and evolution 163 (1989), S. 211-226 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Loasaceae ; Petalonyx ; Inflorescence ; floral ontogeny ; vascular pattern ; androecium ; gynoecium ; nectary ; symmetry
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    Topics: Biology
    Notes: Abstract Inflorescence and floral structure ofPetalonyx linearis are described to assist in understanding homologies among the diverse flowers ofLoasaceae. The inflorescence consists of racemose axes, along which each individual flower is recaulescent with its subtending leaf. Both floral vascularization and appendage initiations show a set of variations. The pseudomonomerous gynoecium may be derived from a triplacental condition. Nectary position, on a collar on which the perianth and androecium are inserted, appears homologous to the ovarian dome position of the nectary among otherLoasaceae.
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    Plant systematics and evolution 163 (1989), S. 201-209 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Iridaceae ; Moraea inclinata ; M. brevistyla ; Bees ; Anthophoridae ; Halictidae ; Pollination mechanism ; flower morphology
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    Topics: Biology
    Notes: Abstract Individual flowers ofMoraea inclinata are nectariferous and last about six hours. They appear to be pollinated largely by bees in the familyHalictidae (Lasioglossum spp.,Nomia spp.,Zonalictus) and to a lesser extent by bees in the familyAnthophoridae (Amegilla). The mechanism of bee-pollination inM. inclinata is the “Iris type”; i.e., each flower consists of three pollination units (an outer tepal, a partly exserted anther, and the opposed style branch which terminates in a pair of petal-like crests). Bees rarely visit more than one pollination unit per flower. Transferral of pollen to the bee is passive and nototribic although all bees collected on the flowers were female and 55% of the bees carried pollen loads with 2–5 pollen taxa in their scopae.Moraea brevistyla flowers are nectariferous but lack scent and last two days. They are visited infrequently by bees and only one femaleLasioglossum spec. carried the pollen ofM. brevistyla. Unlike flowers ofM. inclinata those ofM. brevistyla deposit pollen only on the head and thorax. Bee-mediated autogamy in both species is avoided due to the erratic foraging patterns of the bees and the flexibility of each stigma lobe as the bee backs out of the flower. Approximately 2–4 flowers in the inflorescences of both species (6–8 flowers/infloresence) develop into capsules.
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    Plant systematics and evolution 163 (1989), S. 187-199 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteraceae ; Marantaceae ; Inflorescence morphology ; monotely and polytely ; homogenization ; racemization ; truncation ; pseudoflorescence
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    Notes: Abstract In contrast toW. Troll's typology of inflorescences which aims at more or less rigid, well defined types, this investigation accentuates the processes that constitute the evolutionary transformations leading from one typical form to another.Troll divided the inflorescences into the two types of monotelic and polytelic synflorescences, the first with a terminal flower on the main axis, the latter with a homogeneous florescence on the indeterminate axis. Both forms are enriched by proximal branches which repeat the structure of the main axis (paracladia). The evolutionary processes leading from the more primitive monotelic type to the advanced polytelic type are truncation (loss of the terminal flower) and homogenization of the distal branches, which thus form a homogeneous florescence. A closer survey of the polytelic groups reveals the fact that, usingTroll's criteria, the same distinction can be found within these groups themselves. Loss of the terminal florescence (truncation of 2nd and higher degree) as well as homogenization of the distal paracladia may lead to florescence-like units of higher complexity. Examples can be found inAsteraceae (Figs. 1 and 2),Fabaceae (Fig. 3 a),Mimosaceae (Fig. 3 b),Acanthaceae, and also in Monocots, as exemplified by theMarantaceae (Figs. 4 and 5). The so-called racemization (inversion of efflorescences from basipetalous to acropetalous) may be mentioned as a third element of transformation, emphasizing the unity of the florescences.—In consequence, there are more organizational levels than reflected in the twoTroll types. The polytelic type comprises several degrees of truncation and homogenization, the basis for a reasonable organizational analysis should therefore be the degree of ramification of flowering branches rather than the mere question of a terminal flower on the main shoot axis (Fig. 6). On the other hand the three processes of truncation, homogenization and racemization are evolutionary transformations that may occur independently from one another, thus giving rise to a large number of variations, which can not be satisfactorily interpreted by exactly defined types. On the basis of these considerations the question of homologous parts in inflorescences is reviewed. The homology of partial florescences and paracladia is accentuated contrary toTroll's interpretation (Fig. 7). Homogenization as an evolutionary trend may transform paracladia of different degree of ramification, leading to one-flowered units on the one side and to highly complex structures as in theMarantaceae on the other.
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    Plant systematics and evolution 163 (1989), S. 227-280 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Papaveraceae ; Hypecoum ; Taxonomy ; morphological variation ; mating system ; autogamy ; UV-reflection ; pollen morphology ; chromosome numbers
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    Topics: Biology
    Notes: Abstract Hypecoum sect.Hypecoum comprises 8 species, one with 2 additional subspecies, in the Mediterranean area and the Middle East. Five of these are recognized for the first time, viz.Hypecoum procumbens L. subsp.fragrantissimum Å. E. Dahl,H. procumbens L. subsp.atropunctatum Å. E. Dahl,H. trullatum Å. E. Dahl,H. angustilobum Å. E. Dahl andH. torulosum Å. E. Dahl. H. dimidiatum Delile andH. pseudograndiflorum Petr., which have generally been included inH. imberbe Sm., are reestablished as distinct species. Morphology and variation patterns are described and discussed with special reference to mating systems. Self-incompatibility is dominating butH. procumbens subsp.procumbens andH. torulosum are self-compatible. The broad variation ranges of the former taxon in traits presumably related to mating system (petal, anther and stigma sizes as well as pollenovule ratios) indicate varying rates of outcrossing. SEM micrographs are given of petal and stigma surfaces and of pollen grains. Chromosome counts are presented for seven taxa. All are diploid with 2n = 16.
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    Protoplasma 152 (1989), S. 57-64 
    ISSN: 1615-6102
    Keywords: Angiosperms ; Plastid inheritance, uniparental ; Plastid inheritance, biparental ; Plastid distribution ; Plastid transmission
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  • 58
    ISSN: 1573-8221
    Keywords: c-src locus ; calcium ; Na+, K+-cotransport
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    Topics: Biology , Medicine
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    Cellular and molecular neurobiology 9 (1989), S. 141-178 
    ISSN: 1573-6830
    Keywords: specific desensitization ; nicotinic acetylcholine receptor ; molecular mechanisms ; affinity transitions ; modulators of desensitization ; noncompetitive blockers ; calcium ; substance P ; thymic hormones ; thymopoietin ; thymopentin ; calcitonin gene-related peptide ; receptor phosphorylation ; receptor methylation ; myasthenia gravis
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    Notes: Summary 1. Loss of response after prolonged or repeated application of stimulus is generally termed desensitization. A wide variety of phenomena occurring in living organisms falls under this general definition of desensitization. There are two main types of desensitization processes: specific and non-specific. 2. Desensitization of the nicotinic acetylcholine receptor is triggered by prolonged or repeated exposure to agonists and results in inactivation of its ion channel. It is a case of specific desensitization and is an intrinsic molecular property of the receptor. 3. Desensitization of the nicotinic acetylcholine receptor at the neuromuscular junction was first reported by Katz and Thesleff in 1957. Desensitization of the receptor has been demonstrated by rapid kinetic techniques and also by the characteristic “burst kinetics” obtained from single-channel recordings of receptor activity in native as well as in reconstituted membranes. In spite of a number of studies, the detailed molecular mechanism of the nicotinic acetylcholine receptor desensitization is not known with certainty. The progress of desensitization is accompanied by an increase in affinity of the receptor for its agonist. This change in affinity is attributed to a conformational change of the receptor, as detected by spectroscopic and kinetic studies. A four-state general model is consistent with the major experimental observations. 4. Desensitization of the nicotinic acetylcholine receptor can be potentially modulated by exogenous and endogenous substances and by covalent modifications of the receptor structure. Modulators include the noncompetitive blockers, calcium, the thymic hormone peptides (thymopoietin and thymopentin), substanceP, the calcitonin gene-related peptide, and receptor phosphorylation. Phosphorylation is an important posttranslational covalent modification that is correlated with the regulation and desensitization of the receptor through various protein kinases. 5. Although the physiological significance of desensitization of the nicotinic receptor is not yet fully understood, desensitization of receptors probably plays a significant role in the operation of the neuronal networks associated in memory and learning processes. Desensitization of the nicotinic receptor could also possibly be related to the neuromuscular disease, myasthenia gravis.
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    Plant and soil 115 (1989), S. 53-58 
    ISSN: 1573-5036
    Keywords: ammonia volatilization ; calcium ; magnesium ; manure
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Ammonia volatilization during aerobic decomposition of poultry manure was significantly reduced through additions of calcium and magnesium salts. The percentage reduction in ammonia loss decreased during the 48 day decomposition period from 85–100% in the first 2–3 weeks, to 23–52% at the end of the experiment. The maximum amount of ammonia which was retained (i.e. maximum reduction in ammonia loss) through addition of the chloride salts of Mg2+ or Ca2+ was independent of the type of cation. However, CaCl2 released some of the ammonia initially retained as production of CO2 and NH3 from the manure decreased after 3 weeks of decomposition, whereas both MgCl2 and MgSO4 did not release any of the initially retained ammonia over the 7 week incubation period. Over the entire incubation period MgCl2 therefore retained more ammonia than CaCl2. Magnesium sulphate was considerably less effective in retaining ammonia than either chloride salts.
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  • 61
    ISSN: 1573-5036
    Keywords: aluminium ; calcium ; manganese ; needles ; soil solution ; spruce ; toxicity
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Soil solution and needles of three mature spruce stands in Upper Austria were analysed in order to investigate the uptake and possible toxic effects of Mn and Al, as these two elements become highly mobilised in the soil due to increasing acidity. The Ca/Al molar ratio in the soil solution was below 0.2 in the most damaged stand during almost the whole vegetation period. Despite different dynamics, Al reaches almost identical values in all stands at the end of the vegetation period in both 1-year (current) and 2-year-old needles, respectively. Therefore, needle analysis is not a useful tool for estimation of free Al in the soil. Needle contents of other elements could provide a better information for understanding the forest decline. Mn in the needles correlates significantly with Mn concentrations in the soil solution. As soil Mn will be mobilised by acidic input, Mn needle content can increase to very high levels. Manganese distribution, its interaction with calcium, and possible toxic effects are discussed.
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    Plant and soil 119 (1989), S. 186-190 
    ISSN: 1573-5036
    Keywords: ammonium ; calcium ; forest soil ; ion exchange resin ; magnesium ; manganese ; nitrate ; phosphorus ; soil analysis
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Cation and anion exchange resin bags were placed just under the humus layer at five adjacent forest sample sites with differing site quality classes in order to assess the available nutrient supply. For comparison, humus samples were collected from the same sites. Nutrients were extracted from humus samples by conventional extraction methods and by shaking together with ion exchange resin bags. Ca and Mg corresponded best to differences in site quality class, of all analysed ions in thein situ resin bag eluates. Thein situ resin bag adsorption of NH4−N, Na and Mn also showed a positive correlation with site quality. The adsorption of PO4−P was negatively correlated to site quality class. Inadequate amounts of exchange resin, or leaving resin bagsin situ for too long a time result in the replacement of already adsorbed ions by ions with higher ion exchange constants.
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    Plant and soil 119 (1989), S. 181-185 
    ISSN: 1573-5036
    Keywords: aluminium toxicity ; calcium ; honeylocust ; root biomass ; root branching ; soil acidification
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Honeylocust (Gleditsia triancanthos L.) root growth response to varying levels of Al and Ca in soil solutions was examined in two horizons each of two forest soils. With results from all four horizons combined, multiple regression analysis indicated that both Ca and Al were significant (p〈0.01) factors affecting root elongation, branching and biomass production. Over a wide range of Al and Ca concentrations in soil solutions from four different soil horizons, the Ca:Al ratio was a significantly better predictor of honeylocust root response to acid soils than Al or Ca alone.
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    Bioscience reports 9 (1989), S. 497-502 
    ISSN: 1573-4935
    Keywords: calcium ; phosphatidate ; DPH ; phase fluorometry ; distributional analysis
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Calcium interaction with phospholipid membranes containing phosphatidic acid is studied by multifrequency phase fluorometry, using DPH as fluorescent molecule. DPH decay is analysed by a continuous distribution of lifetimes. The results suggest an increase of membrane heterogeneity at low calcium concentrations, without changes in the polarity of the environment surrounding the probe.
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    Journal of pharmacokinetics and pharmacodynamics 17 (1989), S. 631-644 
    ISSN: 1573-8744
    Keywords: calcium ; absorption ; efficiency ; dosing ; regimens
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    Topics: Chemistry and Pharmacology
    Notes: Abstract The absorption of calcium involves a saturable (active) and a nonsaturable (passive) component. The work of several investigators indicates that an inverse relationship exists between calcium intake and absorption efficiency. Human calcium absorption data from the literature were analyzed using a model which included both an active and a passive absorption component. Simulations were provided to illustrate the suitability of this model, and another previously reported model, to fit the data and to estimate the absorption efficiency of calcium when using different dosing regimens. Comparisons of the values predicted in this study with some literature values are provided and some assumptions and potential limitations associated with the use of this method are discussed. The division of the daily dose into equal increments taken at equally spaced intervals over the course of the day is recommended as a useful procedure for increasing the absorption efficiency and efficacy of calcium.
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    Plant systematics and evolution 163 (1989), S. 1-12 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteridae ; Verbenaceae ; Oleaceae ; Nyctanthes ; Intranuclear inclusions ; mesophyll cells ; ultrastructure
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    Topics: Biology
    Notes: Abstract TEM observations were carried out on 40 taxa of the familyVerbenaceae and 35 taxa of the familyOleaceae, in order to ascertain distribution, ultrastructure and morphology of the intranuclear proteinic inclusions in the mesophyll parenchymatic cells. The investigated genera amount to some 25% and 60% respectively of the genera of the two families. Inside theVerbenaceae, lamellar inclusions (L-type) occur in 6 out of 23 investigated genera: they are mostly present inside the tribesCitharexyleae andVerbeneae (both belonging toVerbenoideae), while they are absent in other subfamilies. All of the investigatedOleaceae genera show intranuclear crystalline inclusions (C 1-type) of three different shapes. Among theAsteridae this is a character peculiar toOleaceae. They appear to be a well defined natural group, including the controversial genusNyctanthes.
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    Plant systematics and evolution 163 (1989), S. 13-20 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Aegilops cylindrica var.kastorianum ; New variety ; karyotype analysis ; protein and esterase patterns ; isoelectric focusing
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    Notes: Abstract A native population ofAegilops cylindrica was encountered for the first time in Greece in 1980 (near Kastoria, NW. Greece), completely isolated and at a great distance from its main distribution area. There are morphological and chromosomal, but no protein and esterase pattern differences from otherAe. cylindrica populations. This justifies the recognition of a new variety: var.kastorianum. Our comparative and karyotypic observations support the view thatAe. caudata var.polyathera and not var.caudata (typica) is the possible donor of genome C of the new variety.
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    Plant systematics and evolution 163 (1989), S. 31-34 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Aristolochiaceae ; Aristolochia krisagathra spec. nova ; A. indica ; Ornithoptera ; Taxonomy ; butterflies ; host plants ; Flora of India
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    Notes: Abstract Aristolochia krisagathra, a new species from the Western Ghats of Peninsular India is described, illustrated and included into a key to the four Indian species of the genus. Notes on the host-relationships of these species are also provided, paticularly ofA. indica to papilionid butterflies.
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    Plant systematics and evolution 163 (1989), S. 21-29 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Sarraceniaceae ; Melastomataceae ; Rapateaceae ; Gentianaceae ; Loranthaceae ; Malpighiaceae ; Ericaceae ; Orchidaceae ; Campylopterus duidae ; Diglossa duidae ; Anoura geoffroyi ; africanized honey bee ; Pollination by bees ; buzz pollination ; Flora of Neblina
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    Topics: Biology
    Notes: Abstract During 20 days in 1985, floral biological observations were made at 1 850–2 100m elevation on Cerro de la Neblina in Venezuela.Heliamphora tatei var.neblinae (Sarraceniaceae) is nectarless and has poricidal anthers.Heliamphora tatei, Graffenrieda fruticosa, G. polymera, G. reticulata, Tocca pachystachya, T. tepuiensis (Melastomataceae),Saxofridericia compressa, andStegolepsis neblinensis (Rapateaceae), are buzz-pollinated by ten species ofBombus, Eulaema, Melipona, Centris, Xylocopa, Dialictus, andNeocorynura. Additional observations of floral visits on tepui species ofGentianaceae, Loranthaceae, Malpighiaceae, Ericaceae, Orchidaceae, andAsteraceae are reported. Visitors include the hummingbirdCampylopterus duidae, the flower-piercerDiglossa duidae, the nectarivorous batAnoura geoffroyi, and various species ofCentris andBombus bees. Scent baits for euglossine bees attracted very few bees.Apis mellifera adansonii-scutellata, the africanized honey bee, was caught at 1 850m elevation.
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    Plant systematics and evolution 163 (1989), S. 71-79 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Ericaceae ; Arctostaphylos ; Arctous ; Calluna Erica ; Loiseleuria ; Rhododendron ; Rhodothamnus ; Oxycoccus ; Vaccinium ; Empetraceae ; Empetrum ; n-Alkanes ; epicuticular waxes ; chemotaxonomy ; environmental effects
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    Topics: Biology
    Notes: Abstract Alkane distribution patterns were determined in the epicuticular wax of the leaves of 13 species and a hybrid fromEricaceae and one species ofEmpetrum (Empetraceae). As chemotaxonomic indicators, the results are of limited use only. The most uniform genus wasRhododendron, the most heterogeneousVaccinium. The dominant effect of genetic over environmental factors was apparent in most cases.
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    Plant systematics and evolution 162 (1989), S. 315-329 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Aceraceae ; Betulaceae ; Celastraceae ; Fagaceae ; Juglandaceae ; Oleaceae ; Rosaceae ; Staphyleaceae ; Summer-green woody plants ; submediterranean ; distribution types ; climatic conditions ; post-Pleistocene dispersal
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    Topics: Biology
    Notes: Abstract The deciduous wood flora of southern Europe is characterized as a special “nemoral-Submediterranean element”. The distribution patterns of some representatives (total ranges and local areas in Roumania) are described and explained by recent climatic conditions. The northern limits of Submediterranean and Submediterranean-middle European deciduous forest taxa exhibit a continuous gradation, but only a few species with a wide ecological amplitude extend into the temperate zone.
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  • 72
    ISSN: 1615-6110
    Keywords: Angiosperms ; Hyacinthaceae ; Scilla cilicica ; S. morrisii ; Karyotype evolution ; C-banding ; genome size ; Endemism ; flora of Cyprus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract S. cilicica Siehe andS. morrisii Meikle are two little known sibling species of theScilla siberica alliance with previously difficult taxonomy, especially with regard to specific delimitation and geographic distribution. Quantitative C-band karyotyping and DNA content determinations were performed in four provenances, including the type localities. Both species (2n = 12) differ strikingly in their banding patterns despite of similar DNA content. Karyotype diversification involved changes in eu- and heterochromatin quantities and resulted in some changes of chromosome form. Despite this, actual phylogenetic relatedness is indicated by a chromosomal marker (NOR-position) of rare occurrence in the alliance. Karyological results and circumstantial evidence from the literature suggest thatS. morrisii is an endemic, exclusive to Cyprus as a member of theS. siberica alliance.S. cilicica seems to be restricted to continental S. Anatolia opposite to Cyprus. Its occurrence on Cyprus is questionable.
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    Plant systematics and evolution 165 (1989), S. 95-100 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Gesneriaceae ; Didymocarpus ; Morphology ; floral ecology ; Flora of Malaysia ; SE. Asia
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    Topics: Biology
    Notes: Abstract Didymocarpus geitleri spec. nov. is described from Sungai Pandan, Kuantan distr., Pahang, Peninsular Malaysia. Distinctive features include: leaden-grey leaves with long, erect hairs on the upper side and whitish, campanulate flowers with a long exserted, bright yellow style. The colouring of the latter is caused by densely arranged glands. Together with two yellow blotches in front of the filament insertion, the style apparently acts as an anther (pollen) dummy.
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    Plant systematics and evolution 165 (1989), S. 189-198 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Iridaceae ; Gladiolus ; G. atroviolaceus ; G. communis ; G. illyricus ; G. imbricatus ; G. italicus ; Geography ; morphology ; multivariate analysis ; chromosome numbers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Representative specimens of the EuropeanGladiolus species (excl.G. palustris) were used to study variability and relationships. 25 characters were measured for cluster, principal component and Wells hybrid analyses (Figs. 1–3). Three (with PCA) respective five (cluster analysis) main groups are revealed. Bulb characteristics appear to be very useful for indentification. The subspecific status ofG. communis subsp.byzantinus is confirmed. Hybrids of four different parental combinations were detected in our collection. Most species include polyploid series. Partly 3x, 4x, 6x, 8x, 12x and aneuploid cytotypes but no diploids were found. Polyploids as pioneers and hybridization of sympatric species are apparently linked to migrations during the glacial periods.
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    Plant systematics and evolution 165 (1989), S. 239-254 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Myrtaceae ; Eucalyptus ; Eudesmia ; Floral morphology ; corolla ; operculum ; androecium ; staminophore ; growth centres ; continuity ; heterotopy ; epipetaly
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    Notes: Abstract In the early stages of ontogeny, the corolline parts of theEudesmia eucalypts develop as compound structures directly comparable to the early stages of the petals ofAngophora and the bloodwood eucalypts, but with the onset of androecial formation a marked difference takes place. Rather than forming on the floral apex, the stamen primordia arise on the basal adaxial components of the young corolline parts; this basal component develops into the staminophore of the mature flower. The operculum consists only of the dorsal components of the corolline parts, the homologues of the “dorsal keels” of theAngophora petals. If the corolline parts remain more or less free in their early developmental stages, corresponding groups of stamens are produced. Early corolline continuity leads to a continuous ring of stamens. The staminophore is not an organ sui generis, but a derivative of the corolla. The bundles of stamens in some species are best referred to as epipetalous groups, not antepetalous fascicles.
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    Plant systematics and evolution 166 (1989), S. 91-104 
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    Keywords: Angiosperms ; Poaceae ; Agropyron ; Elymus ; Biometrics ; Wells' distance diagram ; morphological variation ; Flora of S. America ; Patagonia ; Tierra del Fuego ; Falkland Islands
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    Notes: Abstract Based on a simple multivariate analysis of the morphology of theAgropyron pubiflorum complex—A. patagonicum, A. antarcticum, A. fuegianum, andA. magellanicum—the variation pattern is shown to be clinal, and all taxa are included in a single, variable species. Currently the majority of species ofAgropyron is included inElymus and the correct name of this species isE. glaucescens.
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    Plant systematics and evolution 166 (1989), S. 79-89 
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    Keywords: Angiosperms ; Liliaceae ; Hyacinthaceae ; Ornithogalum tenuifolium ; Evolution of karyotypes ; bimodal karyotypes ; DNA content ; Feulgen densitometry ; hybrids ; meiotic chromosome pairing ; fitness
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    Notes: Abstract Hypotheses on the evolution of the karyotypes of 8 chromosome races (2n = 4, 6, 8, 10, 12, 16-two forms, 26) within theOrnithogalum tenuifolium complex are discussed. Four of the karyotypes are strictly bimodal: 2n = 8 (6 long and two short chromosomes), 2n = 10 (6 long and 4 short chromosomes), 2n = 12 (6 long and 6 short chromosomes) and 2n = 16 (12 long and 4 short chromosomes). The hypotheses are tested by means of measurements of nuclear DNA content, studies of meiosis and pollen fertility of hybrids, and comparisons of karyotype morphology. The results indicate that the E. African 2n = 12 chromosome race is the most primitive and has given rise to the other chromosome races. The 2n = 6 race is found to have a significantly higher fitness than the 2n = 12 race.
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    Plant systematics and evolution 166 (1989), S. 141-158 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Proteaceae ; Conospermum taxifolium ; C. longifolium ; Biosystematics ; numerical taxonomy ; morphology ; allozymes ; electrophoresis ; Flora of Australia
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    Notes: Abstract A morphometric analysis of 18 attributes of 110 plants of theConospermum taxifolium complex suggests that it consists of three polythetically distinct taxa, corresponding to the traditional concepts ofC. taxifolium Smith s. str.,C. ericifolium Smith andC. ellipticum Smith. Discrimination is possible on the basis of leaf but not flower attributes. Analysis of allozymic variation indicates that the taxa are also genotypically differentiated.C. ericifolium andC. ellipticum are geographically isolated from each other but not fromC. taxifolium, andC. taxifolium is usually ecologically segregated from the other two taxa. Where this ecological segregation breaks down, morphological intermediates sometimes occur as the result of hybridization.
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    Plant systematics and evolution 166 (1989), S. 173-181 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Eragrostis curvula ; Lovegrasses ; Esterase isozymes ; disc electrophoresis ; biosystematics
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    Notes: Abstract The biosystematic relationships of the apomictic complexEragrostis curvula s. lato, is investigated by disc electrophoresis of seed extracts to obtain esterase patterns of 23 accessions representing the morphological variants of this complex: curvula, conferta, robusta, chloromelas and lehmanniana. The zymograms thus obtained were classified into four groups on the basis of the presence of certain bands taken as characteristic and constant markers. Within each group variations were found in strict accordance with the morphological and cytogenetic data available on the complex. Cluster analysis showed similarity levels between the strains studied, representing different genomic groups. The esterase pattern proved useful as an additional criterion for identifying the individual taxa making up the complex and for evaluating their reciprocal relationships.
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    Plant systematics and evolution 167 (1989), S. 43-57 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Chenopodiaceae ; Chenopodium ; Taxonomic trees ; phenograms ; cladograms ; natural classifications ; predictivity ; information content ; probability of trees
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    Notes: Abstract The contribution ofJ. S. L. Gilmour to numerical taxonomy is reviewed. His important concept of natural classification, as being general-purpose classifications with high predictivity, led to the development of ideas of information content, unit characters and equal character-weighting. The concept of predicitivity is extended to taxonomic trees (phenograms or cladograms). Under certain assumption of random sampling of characters it is shown that the probability of recovering the correct tree topology or tree-form may be small if characters are few. There may be very many topologies or tree-forms, every one of which has individually a low probability. It is, however, possible to estimate the aggregate probability of trees which have more than some specified resemblance to the “correct” tree. The practical prospects of estimating the distribution of tree probabilities are discussed.
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  • 81
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    Keywords: Angiosperms ; Ranunculaceae ; Ranunculus auricomus agg. ; Ranunculus marsicus ; Cytofluorimetry ; polyploidy ; agamic complex
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    Notes: Abstract A cytofluorimetric method for DNA amount determination on nuclei released from fixed leaves has been successfully tested on samples belonging to the polyploid series ofRanunculus marsicus Guss & Ten. (sect.Auricomus). The procedure was devised to screen rapidly for different ploidy levels within topodemes and progenies.
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    Plant systematics and evolution 168 (1989), S. 7-18 
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    Keywords: Angiosperms ; Fagaceae ; Castanea ; Lithocarpus ; Comparative morphology ; cupule ; ontogenetic development
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    Notes: Abstract Two contradicting theories have been proposed for the morphological nature of fagaceous cupules; the intercalary growth theory and the higher order dichasial branch theory. All the previous ontogenetic studies insist on the latter one, but the genera investigated have been rather restricted and have not covered all the cupule types. A comparative study of the ontogenetic development of cupules inCastanea crenata andLithocarpus edulis, which are representatives of fundamentally different cupule types, revealed that both the theories are incomplete. InL. edulis, the higher order dichasial branches contribute to cupule formation along the anterior portions of the lateral flowers. However, along the adaxial portion of the central flower, the cupule develops as an intercalary growth, represented by rapid increase of tangentially oblong epidermal cells. InCastanea, intercalary growth is not clearly observable, for presumably, the flowers are surrounded by a well-developed partial inflorescence mound from the beginning of development.
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    Plant systematics and evolution 166 (1989), S. 159-171 
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    Keywords: Angiosperms ; Poaceae ; Triticeae ; Biosystematics ; genome analysis ; chromosome homology ; phylogenetic reconstruction ; classification
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    Notes: Abstract The implications of genome analysis for evolutionary theory and systematics are treated. The precise relationship between the theoretical and operational definitions of chromosome homology is shown to be uncertain. It is pointed out that genera defined by genome analysis may be either monophyletic or non-monophyletic, and that the genus is not a basic unit of evolution. Characters obtained by genome analysis may be useful in a phylogenetic context, provided they are treated as all other characters.
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    Plant systematics and evolution 166 (1989), S. 243-248 
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    Keywords: Angiosperms ; Viscaceae ; Viscum ; Nuclear DNA content ; DNA denaturation ; DNA reassociation ; host-specific DNA organization ; subspecific genome differentiation
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    Notes: Abstract The nuclear DNA content and composition with respect to base composition and the proportion of repetitive DNA was studied in the host-specific mistletoe subspecies,Viscum album subsp.album, V. a. subsp.abietis andV. a. subsp.laxum, using DNA ofLoranthus europaeus as a standard. Small but not significant differences were found between the 2C DNA contents and the base composition but significant differences were detected in the patterns of sequence organization. This infraspecific variation is briefly discussed in the light of differences known to occur in the patterns of lectins and viscotoxins, immunostimulating and cancerostatic effects.
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    Plant systematics and evolution 166 (1989), S. 253-264 
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    Keywords: Angiosperms ; orchids ; Pleione ; P. bulbocodioides ; P. formosana ; P. yunnanensis ; P. humilis ; P. forrestii ; Chromosome banding ; Feulgen staining ; karyotype analysis ; epiphytic ; semi-terrestrial ; terrestrial habitats
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    Notes: Abstract Karyotypic and heterochromatin studies suggest a basic division of the orchid genusPleione into two groups, one represented by the clearly epiphytic species and the other including both species with terrestrial trends as well as those that are truly terrestrial. The epiphytic group possesses only (sub) metacentric chromosomes and is characterised by a considerable amount of terminal heterochromatin while the terrestrial group has some subtelocentric chromosomes and only small amounts of centromeric heterochromatin. It is concluded that a major phyletic split in the mode of chromosome change occurred during the transition from the epiphytic to the terrestrial habitat.
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    Plant systematics and evolution 167 (1989), S. 113-127 
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    Keywords: Angiosperms ; Boraginaceae ; Symphytum ; S. officinale agg. ; Chemotaxonomy ; pyrrolizidine alkaloids ; isobauerenol
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    Notes: Abstract In a chemotaxonomic study of the genusSymphytum pyrrolizidine alkaloids and triterpenes were used as chemotaxonomical markers. A micro-extraction methods was developed for screening compounds of very small pieces of herbarium material. The occurrence of the pyrrolizidine alkaloids symphytine and (acetyl-)lycopsamine is very general forSymphytum taxa. Echimidine is present in someS. officinale L. plants and inS. tanaicense Steven. The triterpene isobauerenol is present inS. officinale, S. bohemicum Schmidt,S. tanaicense and inS. officinale var.lanceolatum Weinm. The chemotaxonomic hypothesis, proposed byGadella and collaborators, based on the presence of the triterpene isobauerenol inS. officinale and its absence inS. asperum Lepech. and the presence of the pyrrolizidine alkaloid echimidine inS. asperum and its absence inS. officinale, can no longer be applied absolutely to theS. officinale species complex. The pyrrolizidine alkaloid and triterpene pattern ofS. officinale (2n = 24) andS. bohemicum (2n = 24) is identical.S. bohemicum is morphologically, cytologically and phytochemically very similar toS. officinale. Furthermore, it readily crosses with the white flowered W. European diploids ofS. officinale. Therefore it seems likely that these two taxa are conspecific.S. tanaicense shows a pyrrolizidine alkaloid and triterpene pattern similar toS. officinale (2n = 40). Also on morphological and cytological grounds they are very similar. It seems highly probable thatS. tanaicense is conspecific withS. officinale (2n = 40) and represents an intraspecific variant only.S. officinale var.lanceolatum contained no pyrrolizidine alkaloids but did contain isobauerenol. This feature points to an origin fromS. officinale.
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    Plant systematics and evolution 167 (1989), S. 149-164 
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    Keywords: Angiosperms ; Compositae ; Cichorium intybus ; Tapetum ; pollen ; exine ; pollenkitt
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    Notes: Abstract The tapetal development ofCichorium intybus L. is investigated using LM and TEM and discussed in relation to the development in other species. During the second meiotic division the tapetal cells become binucleate and lose their cell walls. They intrude the loculus at the time of microspore release from the meiotic callose walls, which means that a locular cavity is never present in this species. During pollen development they tightly junct the exine, especially near the tips of the spines. During the two-celled pollen grain stage they degenerate and most of their content turns into pollenkitt. Until anther dehiscence they keep their individuality, which means that these intruding tapetal cells never fuse to form a periplasmodium. The ultrastructural cytoplasmatic changes during this development are discussed in relation to possible functions.
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    Plant systematics and evolution 168 (1989), S. 59-69 
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    Keywords: Angiosperms ; Fabaceae ; pigeonpea ; Cajanus cajan ; Sex allocation ; mating systems ; fruit and seed set
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    Notes: Abstract Sex allocation theory predicts that: (1) resources allocated to androecium should decrease with an increase in selfing, (2) a decrease in androecium biomass should be accompanied by an increase in the biomass of pistils, and (3) a decrease in androecium biomass should be coupled with a decrease in flower size, specifically corolla biomass. Another predicted change in reproductive traits associated with variation in selfing concerns seed to ovule ratios, but does not directly stem from sex allocation theory. It has been postulated that seed to ovule ratios should be positively correlated with the amount of selfing. These predictions were tested for six accessions of pigeonpea,Cajanus cajan L., that differed in selfing rates. The results were remarkably in accordance with the predictions. We conclude that sex allocation theory provides a powerful tool to understand the evolution of many reproductive traits in plants.
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    Plant systematics and evolution 168 (1989), S. 87-94 
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    Keywords: Angiosperms ; Apiaceae ; Pimpinella major ; P. saxifraga ; P. alpina ; Asteraceae ; Solidago virgaurea ; S. canadensis ; S. gigantea ; Exploratory data analysis (EDA) ; classification algorithm ; MOBCENTR
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    Notes: Abstract MOBCENTR is a classification algorithm combining features of classification about mobile centres, Ward algorithm and of the Hard-Isodata method. The results of this new algorithm and of Ward algorithm are compared by morphological characters of species ofSolidago andPimpinella.
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    Plant systematics and evolution 168 (1989), S. 181-193 
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    Keywords: Angiosperms ; Ranunculaceae ; Adonis ; Taxonomy ; distribution ; cytology ; chromosome numbers ; meiosis
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    Notes: Abstract The five annual species ofAdonis L., sect.Adonis, growing in Israel, form a series of diploid, tetraploid and hexaploid species. Their somatic chromosome numbers are 2n = 16 inA. annua L.,A. dentata Del. andA. palaestina Boiss., 2n = 32 inA. microcarpa DC., 2n = 48 inA. aestivalis L.; counts forA. dentata, A. palaestina andA. microcarpa are new records. There are indications that alloploidization may have been involved in the process of speciation in sect.Adonis. A taxonomic survey of the 8 species of the section reveals that a higher ploidy level is usually combined with a larger distribution area.
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    Plant systematics and evolution 162 (1989), S. 5-61 
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    Keywords: Angiosperms ; Nypa ; Ctenolophon ; Bombacaceae ; Olacaceae ; Symplocos ; Alangium ; Nepenthes ; Pachysandra andSarcococca ; Restionaceae ; Chloranthaceae ; Austrobaileyaceae ; Paleogeography ; paleochorology ; chorology ; Neophyticum
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    Notes: Abstract After presenting the methodological bases of historical phytogeography (paleochorology; Fig. 1), a new paleographic map series is introduced (Fig. 2). They serve for ten examples of paleochorological analyses, in which the major phases of the development of a group in space and time are documented. In addition to purely tropical taxa (Nypa, Ctenolophon), others which originated in the warm and humid N. Tethyan belt (Bombacaceae p.p.,Olacaceae p.p.,Symplocos, Alangium, Nepenthes) or which presently occur as eastern N. American/E. Asian disjuncts (Sarcococca andPachysandra) are discussed (Figs. 3–14). Finally, analyses of two very old angiosperm groups with complicated paleochorological patterns (Restionaceae andAscarina, Chloranthaceae p.p.; Figs. 15–16) are presented.
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    Plant systematics and evolution 162 (1989), S. 63-78 
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    Keywords: Angiosperms ; Myrtaceae ; Proteaceae ; Casuarinaceae ; Lauraceae ; Nothofagus ; etc. ; Tertiary floras of Australia ; evolution of the Australian flora
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    Notes: Abstract The evolution of the Australian flora through the Tertiary has not been reviewed by a megafossil palaeobotanist for almost a century. Based on material available and published studies, the Australian Tertiary can be considered in three units: Eocene, Oligo-Miocene, and Pliocene. Key taxa in the Eocene includeCasuarinaceae, Proteaceae, Fagaceae, Podocarpaceae, andLauraceae. Many known Eocene deposits are interpreted as warm, humid rainforests. Oligo-Miocene floras reflect a climatic deterioration, with greater occurrence of sclerophylly and xerophylly. A reduction of tropical taxa is seen with an increase ofMyrtaceae and earliest records ofMimosaceae, Chenopodiaceae, andPoaceae. These trends continue into the Pliocene, which is not well represented in Australia. Problems needing to be addressed include the discrepancy between the pollen and megafossil records ofNothofagus, the origins of Australia's wet tropical taxa, and the role of fire in the early evolution of the Australian flora.
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    Plant systematics and evolution 165 (1989), S. 91-94 
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    Keywords: Angiosperms ; Asteraceae ; Heliopsis scabra ; Rudbeckia vulgaris ; Flowers ; UV patterns during anthesis
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    Notes: Abstract The pseudanthia ofHeliopsis scabra andRudbeckia vulgaris (Asteraceae) were examined during the anthesis for differences in their UV patterns. Distinct changes in the reflectance and absorbance properties could be observed. The results suggest a close correlation between different stages of floral development and pollinator attraction.
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    Plant systematics and evolution 165 (1989), S. 85-89 
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    Keywords: Angiosperms ; Alliaceae ; Allium cepa ; Leucoplast ; chloroplast ; plastids ; plastid metamorphosis (transformation)
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    Notes: Abstract The greening of the upper part of the outerAllium cepa L. bulb scales, in particular along the vascular regions, is limited to the hypodermal cells in which typical leucoplasts are transformed to normal and functional chloroplasts. This process is light dependent and cannot afterwards be reversed or modified by darkness. The changes in fine structure are described and briefly discussed.
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    Plant systematics and evolution 165 (1989), S. 101-136 
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    Keywords: Angiosperms ; Rubiaceae ; Rubieae ; Crucianella sect.Roseae ; C. platyphylla (spec. nova) ; C. gilanica (with subspp. and stat. nov.) ; C. suaveolens andC. sintenisii ; Systematic revision ; eco-geographical analysis ; Flora Iranica
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    Notes: Abstract The perennial taxa ofCrucianella in Asia form a coherent group, apparently diploid (x = 11) and outbreeding throughout, and should be placed into sect.Roseae. This Irano-Turanian group has its centre of diversity in the mountain systems south of the Caspian Sea and reaches with outposts NE. and E. Anatolia, NE. Iraq, S. Iran and C. Asia. Four species and 13 subspecies (within the polymorphicC. gilanica) are recognized, described (partly as new), and illustrated (Figs. 1–6). Conspectus, keys and distribution maps (Figs. 7 and 8) as well as plesio- and apomorphic character states and data on size of areas are provided (Table 1). There is an obvious correlation between more plesiomorphic taxa with smaller areas in the distribution centre of the group, and more apomorphic taxa with larger areas towards its periphery (Fig. 9). These findings are linked to a working hypothesis on the evolution of the group.
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    Plant systematics and evolution 165 (1989), S. 159-188 
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    Keywords: Angiosperms ; Solanaceae ; Capsicum ; Isozymes ; genetic distance ; geographic differentiation
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    Notes: Abstract The evolutionary relationships of 186 accessions ofCapsicum from Mexico were studied through enzyme electrophoresis. A total of 76 alleles representing 20 genetic loci coding for nine enzyme systems were observed and the allelic variations of enzymes were studied for geographical distribution. Allele frequencies were used to estimate the apportionment of gene diversity within and between populations and to construct a dendrogram based on a similarity matrix containingNei genetic distances. — The gene diversity estimates suggest that the structure ofCapsicum populations in Mexico consists of predominantly homozygous genotypes presumably due to a self-pollinated breeding system and population bottlenecks. Significant genetic differentiation was found mainly between populations of differing geographical regions.—Based on the results of this study, three species of domesticatedCapsicum can be identified in Mexico,C. annuum var.annuum, C. chinense, andC. pubescens. Semidomesticated and wild forms include two species,C. frutescens andC. annuum var.glabriusculum. A sharp geographical division results between the latter species;C. frutescens was collected exclusively in the southeastern states of Oaxaca, Chiapas, and Tabasco; whereas wild and semidomesticated forms from the rest of the country areC. annuum. Based upon the similarity of enzyme genotypes of semidomesticated and wild forms, the primary center of domestication of cultivatedC. annuum was estimated to be the region comprising the states of Tamaulipas, Nuevo Leon, San Luis Potosi, Veracruz, and Hidalgo in eastern Mexico. A possible second center of domestication is suggested to be localized in the state of Nayarit, western Mexico.
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    Plant systematics and evolution 166 (1989), S. 265-278 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Leguminosae ; Fabaceae ; Genisteae ; Sophoreae ; Thermopsideae ; Lupinus ; Serological systematics ; phylogeny
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    Notes: Abstract The immunological comparison of the seed reserve proteins suggests thatLupinus is a natural genus, the American and the Euro-African species belonging to the same stock. Among the Lupines of the Old World, the smooth-seeded and the rough-seeded species from two natural segregates. The genusLupinus is serologically related to the rest of theGenisteae and to the AsiaticSophoreae rather than to AmericanSophoreae andThermopsideae. The data suggest thatLupinus may have originated with the remainder of theGenisteae from primitiveSophoreae of temperate-subtropical Asia. America and the Mediterranean-African region are regarded as secondary centres of speciation.
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    Plant systematics and evolution 166 (1989), S. 1-9 
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    Keywords: Angiosperms ; Orchidaceae ; Epidendreae ; Liparidinae ; Liparis paradoxa ; Liparis rostrata ; Embryology ; systematics
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    Notes: Abstract The embryology ofLiparis paradoxa andL. rostrata has been studied. The young anther wall consists of an epidermis, endothecium, three middle layers and secretory tapetum with uninucleate cells. In the mature anther, two or three sub-epidermal layers develop fibrous thickenings. The anther wall development corresponds to the massive type. Simultaneous cytokinesis results in decussate, isobilateral, linear, T-shaped and tetrahedral pollen tetrads. The pollinia are compact and at anthesis the pollen grains are 2-celled. Ovules are anatropous, bitegmic and tenuinucellate. Both the integuments are dermal in origin and 2-layered. Development of female gametophyte is of the monosporic, 8-nucleate type. Double fertilization occurs. The primary endosperm nucleus degenerates. The mature embryo is organized from the derivatives of tiers 1, 1′, m, and n. Its development conforms to a variation of the Onagrad type. The seed coat is formed entirely by the outer layer of the outer integument. There are three sterile and three fertile valves in the ovary. In the prefertilization stages valves consist of parenchymatous cells. After fertilization, the sterile valves become sclerenchymatous whereas the fertile valves remain parenchymatous. The embryological characters support the disputed systematic position ofLiparis within subtribeLiparidinae ofEpidendreae.
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    Springer
    Plant systematics and evolution 166 (1989), S. 31-39 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Solanaceae ; Nicotianeae ; Benthamiella pycnophylloides ; Combera paradoxa ; Pantacantha ameghinoi ; Somatic chromosome numbers ; karyotype analyses ; taxonomic and phylogenetic significance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The somatic chromosomes and karyotypes of threeNicotianeae have been studied for the first time. All of them have 2n = 2x = 22 and symmetrical karyotypes.Benthamiella pycnophylloides has 9 m pairs + 1 sm pair + 1 st pair; pairs 2, 4, 5, and 11 bear microsatellites.Combera paradoxa andPantacantha ameghinoi have 9 m pairs + 2 sm pairs; pair 11 ofC. paradoxa is satellited, while pair 9 ofP. ameghinoi bears microsatellites and shows a pericentric inversion in heterozygous state in 20% of the seedlings. Results are compared with previous chromosome reports for the tribe. The cytological data support their present position in the family system. Besides,Benthamiella, Combera andPantacantha appear to be primitive genera ofNicotianeae, a comparatively advanced tribe within the family.
    Type of Medium: Electronic Resource
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  • 100
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 166 (1989), S. 105-117 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Piperaceae ; Piper ; Pothomorphe ; Peperomia ; Chromosome numbers ; karyomorphology ; banding patterns ; polyploidy ; evolution and systematics in tropical plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chromosome numbers for 26 different species of the generaPiper, Peperomia andPothomorphe (Piperaceae) are reported. The basic chromosome numbers are 2n = 26, x = 13 (Piper, Pothomorphe) and 2n = 22, x = 11 (Peperomia), polyploid series are characteristic forPiper andPeperomia. Piper has the smallest chromosomes and prochromosomal interphase nuclei,Peperomia the largest ones and mostly reticulate to euchromatic nuclei.Pothomorphe is intermediate in both characters. The karyomorphological differences betweenPothomorphe andPiper underline their generic separation. Interspecific size variation of chromosomes occurs inPiper andPeperomia. Infraspecific polyploidy was observed inPiper betle. C-banding reveals different patterns of heterochromatin (hc) distribution between the genera investigated. The genome evolution is discussed.
    Type of Medium: Electronic Resource
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