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|Type:||Artigo de periódico|
|Title:||The Utilization Of Cotyledonary Reserves In Phaseolus Vulgaris L. Cv. Carioca: Ii. The Effects Of 6-benzy Ladenine And Gibberellic Acid Upon Embryonated And Detached Cotyledons|
|Abstract:||The presence of the embryo axis promotes starch hydrolysis in cotyledons of Phaseolus vulgaris and, although reduced rates of enzyme activity proceed in its absence, weight loss from the cotyledon is only significant in its presence. Application of gibberellic acid at various concentrations had no effect upon amylase or protease activity in either detached or embryonated cotyledons: this was not the case for 6-benzyladenine which promoted both. In detached cotyledons amylolytic activity was directly proportional to the concentration of applied 6-BA; concentrations below 10 -6 M were unable to completely substitute for the presence of the axis, while, above 10 -6 M, hydrolytic activity higher than that of treated embryonated cotyledons was observed. Increasing the concentration of 6-BA had no effect, however, upon the amylolytic activity of embryonated cotyledons. Detached cotyledons showed an increased chlorophyll content and 6-BA treatment further increased this; the proportions of chlorophyll a and chlorophyll b remained unaltered.An inhibitor of amylase activity, destroyed by heating, is present in embryonated cotyledons and can depress amylolysis in detached cotyledons which appear to be inhibitor-free. The results in total suggest that the developing axis may regulate reserve hydrolysis in three distinct manners: firstly, by stimulating the synthesis of amylase via hormonal control, most probably a cytokinin; secondly, by checking the rate of amylolysis by means of an amylase inhibitor; and, thirdly, by being a sink for the products of reserve degradation. © 1980 Oxford University Press.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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