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31.
21-day old plants ofChenopodium rubrum L. ecotype 374 were used. Organ relationships in the shoots were investigated by32P distribution, which indicated different organ correlations in plants grown in continuous light and in plants treated with
flower-inducing and non-inducing dark periods. Dark periods were associated with a low32P distribution in young leaves and a high one in axillary buds. In the following light period the high32P distribution in axillary buds continued whereas the32P distribution in the leaves on the main axis increased and was similar to that in plants grown in continuous light. The high32P distribution in axillary buds was brought about by both, flower-inducing and non-inducing dark treatments. Decapitation
resulted in a high32P distribution in buds, in continuous light an increased32P distribution was also found in leaves. These effects were not fully cancelled by IAA application.
The results are discussed with respect to an assumption that decrease of apical dominance represents a step in a sequence
of events leading to flowering. 相似文献
32.
Ivana Macháková Jan Krekule Dagmar Souková Zdenk Pikryl Jaroslav Ullmann 《Journal of Plant Growth Regulation》1991,10(1):203-209
Aminoethoxyvinylglycine (AVG) applied as a droplet (3 l, 0.1 mM) to the plumule of seedlings of both the short-day plantChenopodium rubrum and the long-day plantChenopodium murale counteracted to a great extent or even canceled the inhibition of flowering due to exogenous indole-3-acetic acid (IAA). This effect was more pronounced with the two substances administered simultaneously than with later application of AVG alone. AVG by itself in some cases promoted the percentage of flowering in bothChenopodium species. Application of IAA to the shoot apex was shown to elevate ethylene production in both species, whereas application of AVG alone was shown to suppress it. Thus, ethylene may be considered an active agent of flowering inhibition brought about by IAA application. 相似文献
33.
34.
Zusammenfassung Freilandbeobachtungen und frühere Laboruntersuchungen (Berthold 1976) führten bisher zu einer widersprüchlichen Bewertung der zugzeitlichen Frugivorie bei der Gartengrasmücke. Deshalb wurden das Wahlverhalten gegenüber verschiedenen Beeren und Früchten in deren natürlichem Gehänge in einer Voliere geprüft sowie die Auswirkung unterschiedlich frugivorer Ernährung auf Körpermasse und tägliche Nahrungsaufnahme unter kontrollierten Laborbedingungen untersucht. Zwischen dem Präferenzverhalten gegenüber bestimmten Beeren und Früchten und deren Profitabilität bzw. Nährstoffgehalt bestand kein eindeutiger Zusammenhang. Demnach ist die Wahl zwischen verschiedenen Vegetabilien nicht einfach abhängig von ihrer Größe oder dem Nährstoffgehalt. Erhebliche Unterschiede zwischen den getesteten Beeren und Früchten zeigten sich bei der täglichen Aufnahmerate und den Auswirkungen auf die Körpermasse. Während bestimmte Beeren nur als Zusatzfutter zu einem immer, wenn auch geringfügig notwendigen, animalischen Standardfutter verabreicht werden konnten, waren die Gartengrasmücken mit Schwarzem Holunder und Feige auch bei ausschließlicher Gabe nicht nur in der Lage, ihre Körpermasse zu halten, sondern konnten dabei sogar normale Fettdeposition vollziehen. Offensichtlich sind bestimmte Vegetabilien für die Gartengrasmücke wesentlich bedeutsamer als bisher angenommen. Die Ergebnisse stimmen somit mit Beobachtungen aus dem Freiland überein. Die beobachteten qualitativen Unterschiede zwischen den Früchten und deren Wirkung auf die Körpermasse der Versuchsvögel ließen sich nicht allein mit dem Nährstoffgehalt der Beeren erklären. Vermutlich spielen die spezifische Qualität der Nährstoffe (z. B. Fettsäurezusammensetzung) und möglicherweise auch sekundäre Pflanzenstoffe eine wichtige Rolle.
The significance of seasonal frugivory in migratory Garden WarblersSylvia borin
Summary In contrast to field observation, exhibiting an important role of seasonal frugivory,Berthold (1976) concluded that fruits are only a supplementary food, and he rejected the hypothesis that songbirds shift to a fruit diet during migration in order to render or to accelerate fat deposition.We investigated the preference of Garden Warblers upon various berries and pulpy fruits in an outdoor aviary. Furthermore, the effects of frugivory on body mass and food intake is measured in caged specimens under controlled laboratory conditions.In almost all feeding trials a significant selection between the two alternative fruit diets are obvious. However, no clearcut relationship between profitability or nutritive content of the various fruits and food choice is evident.In the experiments under controlled laboratory conditions the effects of varying extends of frugivory on body mass and food intake of captive Garden Warblers reveal a considerable difference between various berries and fruits. In some berries, the birds were not able to compensate for a reduction of the standard animal food by increasing frugivory. With Black Elder berries or figs, however, they did not only compensate for to maintain body mass rather they were able to gain mass during migratory fat deposition, even kept on an exclusive fruit diet.These results clearly exhibit a significant role of fruit diets in migrating Garden Warblers, with particular regards to Black Elder berries and figs, respectively.The observed differences between the various fruit diets do not correspond to the crude nutritive content of the pulp. Presumably, the specific quality of nutrients (for instance, fatty acid composition) or even secondary plant compounds have to be considered.The experimental results agree with field observations, indicating the importance of frugivory for the Garden Warbler, and they contradict Berthold's suggestion that fruits are only a least important supplementary food to an always necessary animal food.相似文献
35.
Dagmar Jičínská Eduard Brabec Marcel Rejmánek Jan Jeník Joří Haager Josef Holub Věroslav Samek Hana Rambousková Josef Holub Marie Naděžda Končalová Robert Neuhäusl Josev Kyncl František Krahuleo Jaroslav Dobrý Blanka Úlehlová Jiří Úlehla Eliška Rybníčková Kamil Rybníček 《Folia Geobotanica》1982,17(4):431-448
36.
37.
The inbred strains GRS/A and LIS/A carry the haplotypeH-2
dx
, which had earlier been shown to have theK
d
,I
f
,S
f
, andG
f
alleles and a previously unknownD region allele,D
dx
. We show here that theD
dx
allele determines a new private specificity, H-2.63, is H-2.28 negative, and determines at least one public specificity of the H-2.1 family. It is thus a second example (afterD
k
) of a H-2.1-positive H-2.28-negativeD region allele. Capping experiments show that the Ddx product comprises two molecules: H-2Ddx bearing the private specificity H-2.63, and H-2Ldx, which is H-2.63-negative but reacts with sera against the H-2.1 family of specificities. SDS gel electrophoresis of detergent-solubilized immunoprecipitated Ddx products shows that the H-2Ldx antigen has a molecular weight of approximately 45,000 daltons and is associated with a smaller polypeptide (mol. wt. 12,000). 相似文献
38.
Serological and capping experiments show that the strain B10.D2 (M504) carrying the mutant haplotypeH-2
dm1
has two molecules in the products of theD region: H-2Ddm1 and H-2Ldm1 which are detectable by anti-H-2.4 and by anti-H-2.28 sera, respectively. Both these molecules differ serologically from the H-2Dd and H-2Ld molecules of the original (nonmutant) strain B10.D2. A third molecule, different from H-2D and H-2L, was detected inH-2
d
,H-2
dm2
but not inH-2
dm1
products. 相似文献
39.
Phragmites communis Trin., a highly polymorphous and widely spread species has been described by several authors by the series of polyploidy ranging from triploid to octoploid forms (2n=36 to 96). The original spontaneous diploid form was not known. The present communication describes the experimental transplantation of a dwarf saline form into freshwater substrate conditions, including a new and extremely changed habitus of a sterile plant, the chromosome number of which has been determined as 2n=24. 相似文献
40.
Dagmar Vran 《Biotechnology and bioengineering》1976,18(3):297-309
Cells of Candida utilis grown in a single-stage chemostat at D = 0.05, 0.1, 0.25, and 0.35 hr?l were separated into a fraction of scar-bearing mother cells and a fraction of scar-free daughter cells. The scar-free cells were transferred into small batch cultures where the length of the maturation phase, changes in length and width of cells, specific growth rate, and specific rate of RNA and protein synthesis were examined for 5 hr. The daughter cells grown at D = 0.05 hr?1 were very small at the moment of separation from the mother cells (about one-third of the mother cell). Their maturation phase (in a batch culture), at the beginning of which they attain the specific growth rate approaching the μmax of the strain used, lasts for 3 hr. On the other hand, daughter cells grown at D = 0.35 hr?1 are almost the same size as the mother cells at the moment of separation. After transfer to a batch culture they begin to bud almost immediately. Similarly, in their other morphological and physiological parameters they differ strikingly from immature daughter cells which are formed at low specific growth rates. The importance of these differences from the point of view of mathematical modeling of growth processes is discussed. 相似文献