摘要:

40 aromatic and chlorocyclohexenic structural analogues of abscisic acid were synthesized stereospecifically, and inhibition of transpiration was investigated following two experimental procedures (cut barley leaves and water stressed cotton plants). Structure‐activity relationships are discussed. – Two chlorosubstituted cyclohexenic compounds are the most active; their inhibition of transpiration can be compared to that of abscisic a

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb00869.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Unrolling of 1 cm sections, taken between 3 and 4 cm from the apex, of 6‐day‐old, etiolated barley leaves, was promoted by blue (426 nm) and red (658 nm) light. Accompanying such unrolling was a reduction in the level of the free proline of the tissue. When leaf unrolling was prevented by irradiation with far‐red (728 nm) light, or treatment with abscisic acid (ABA) following red light irradiation, the level of proline remained more or less unchanged, at the level of the untreated, dark controls. The proline analogue, azetidine carboxylic acid (AZC) powerfully inhibited the light induced leaf opening, emphasizing the significance of proline‐containing, structural and functional proteins in barley leaf unrolling. The inhibition imposed by AZC is partially reversible by added

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb00870.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The activities of starch synthesizing enzymes were investigated in wheat grains (Triticum aestivumL. cv. Kolibri) throughout the grain development period. Starch phosphorylase (E.C. 2.4.1.1.) activity was especially high during the early period of grain development, while starch synthase I (ADP glucose α‐glucan 4‐α‐glucosyl‐transferase, E.C. 2.4.1.21) had a maximum activity during the later stage of grain filling. The synthetic potential of starch phosphorylase measuredin vitrowas about 16 times higher than the quantity of starch actually produced. It is therefore suggested that starch phosphorylase is of substantial importance in grain starch synthesis, particularly in the early period of grain growth. The synthetic potential of starch synthase I measuredin vitromade up 25 to 50% of the starch production and the synthetic potential of starch synthase II (UDP glucose α‐glucan 4α‐glucosyl‐transferase. E.C. 2.4.1.11) only about 5%.Reducing light intensity (shading) during the grain filling period depressed grain growth and starch production by about 20%. Starch phosphorylase was not significantly affected by the reduced light intensity if enzyme activity is calculated on unit grain weight and not as activity per grain. Starch synthase I activity, however, was depressed by shading during the later stage of grain development. The depressed starch production found under low light conditions, however, cannot only be explained by an affected starch synthase I activity, but probably was also related to other still unknown factors limiting grain growth under low light conditions. The poor starch production in the shaded plants was not due to an insufficient supp

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb00871.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The light requirement for germination in spores of the fernThelypteriskunthii (Desv.) Morton was fully satisfied by a long period of continuous red light or partially by intermittent, short periods of red light. Red light‐potentiated spore germination was inhibited by brief far‐red light irradiation, indicating phytochrome involvement. Repeated exposure of spores to prolonged red and short far‐red irradiations, or exposure of red‐potentiated spores to far‐red light after an extended period in darkness, led to their escape from inhibition of germination by far‐red light. Prolonged irradiation of spores with blue light before or after red light treatment partially antagonized the effect o

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb00872.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Indol‐3yl‐acetic acid (IAA) present in the rooting solution for 1–4 days appreciably decreased the number of roots subsequently formed in pea stem cuttings. Removal of the lowest 10 mm of the cutting base after IAA treatment abolished the inhibitory effect of IAA almost completely. The number of roots formed from the remaining part of the base internode after excision of the basal centimeter of the internode 4 days after the cuttings were taken was similar to that of the control. It is concluded that the first root primordia, which develop near the cut surface, have an inhibitory influence on development of further roots. The inhibitory effect of IAA may be explained as a strengthening of this dominance phenomenon.Addition of charcoal to the rooting solution delayed the appearance of roots but increased the number of roots developed during a standard rooting period. Adsorption of stimulatory and inhibitory compounds at the surface of the cutting base is believed to be the reason for these results as no evidence of accumulation of inhibitory compounds in the solution was obtained. Charcoal reversed the inhibitory effect of IAA if added after the IAA treatment. This reversal was almost complete if the IAA treatment lasted for one day only but decreased drastically if the IAA treatment was extended over 4

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb00873.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The kinetics of growth and georeaction of horizontal or vertical maize (cv. ORLA 264) apical root segments were analysed. Elongation and curvature data were fitted to a mathematical function and the effect of both light and decapitation reported. Elongation of horizontal segments was found to be more sensitive to light than to decapitation. A light treatment or the decapitation presented several effects on the shape of the growth curves. Growth of vertical segments was affected much more by decapitation than by light treatment. The shape of the curves was clearly different for decapitated and intact segments.Curvature is affected both by light and decapitation but the shape of the bending curves is modified principally by decapitation.Under the present conditions used, growth and georeaction of root segments do not seem to be strictly correlated.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb00874.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Ethylene evolution from leaves, stems, inflorescences and fruits of the olive plant (Olea europaeaL.) cv. Manzanillo was studied at various stages of their development. Mature non‐growing organs, particularly leaves, have a constant, low, and uniform rate of ethylene evolution. Ethylene evolution from detached mature olive leaves was constant during the first 12 h after excision. Leaves on shoots maintainedin vitrokept a constant rate of ethylene evolution for at least the first 5–6 days. Leaf injury significantly increased ethylene evolution. Ethylene evolution from injured and non‐injured control leaves could be markedly inhibited aminoethoxyvinylglycine (AVG) applied to the leaves or fed to the shoot. The use of excised olive shoots and leaves as anin vitromodel system for studies of induced metabolic processes such as abscission and developing water stress was sugg

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb00875.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The pith parenchyma in tomato (Lycopersicum esculentum) stems was found to be disrupted in response to water stress (stem pithiness). The process of the degradation starts at the upper part of the stem and proceeds downwards as the stress is prolonged. The damage to the stem tissue was found to be irreversible upon rehydration of the stressed plants. Scanning electron microscopy revealed that the protoplast of the affected cells is disrupted first, followed by degradation of the cell wall.Application of abscisic acid (ABA) induced pithiness in non‐stressed plants and also enhanced the effect of a short period of dehydration. Kinetin, although causing severe wilting, did not induce pithiness. However, when given after a short period of water stress or within the period of stress, kinetin enhanced pithiness development.In the course of the stress, ABA levels in the upper part of the stem and in the young leaves were higher than the levels found in the lower parts of the plant shoot. The increase in ABA levels was detected before any sign of pithiness.It is suggested that ABA might be the triggering agent of the cellular degradation process initiated by water stres

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb00876.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The distribution and metabolism of {8‐14C}zeatin incorporated into the transpiration stream of fruiting white lupin plants (Lupinus albusL.) has been studied. The distribution pattern of14C in the different aerial organs suggests that the amount of cytokinin being incorporated into any one organ may have been a function of its transpiration rate. Once in these organs, particularly the leaves, zeatin was rapidly metabolised and or utilised. This resulted in the formation of a number of labelled compounds that did not give a response with the soybean callus bioassay. Substances co‐eluting with zeatin glucoside and ribosylzeatin appeared to be the principal biologically active metabolites. From the present evidence it can be concluded that the leaf and side shoots received a major proportion of the applied labelled cytokinin. However, the presence of a small amount of radioactivity co‐eluting with zeatin and ribosylzeatin in the fruits indicates that the high levels of cytokinins normally associated with these organs need not necessarily all have been synthesised in

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb00877.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The fate of {8‐14C}zeatin injected into the mature leaves and oldest fruits of fruiting white lupin plants (Lupinus albusL.) was studied. Applied zeatin was metabolised rapidly by both organs. Within 24 h radio‐ and cytokinin‐like activity that co‐eluted with zeatin glucoside and ribosylzeatin could be detected within them. While no evidence could be found for the export of labelled cytokinins from the fruits there were some indications that zeatin glucoside may have been exported from the mature

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1981.tb00878.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY