Formation of alpha-amylase and endogenous gibberellins in cotyledons of Phaseolus vulgaris
Van Onckelen, H.A.; Caubergs, R.; De Greef, J.A.
Archives Internationales de Physiologie et de Biochimie 83(5): 1019-1020
1975
ISSN/ISBN: 0003-9799 PMID: 58599 Document Number: 95080
alpha -amylase formation in P. vulgaris cotyledons during germination in darkness or in continuous white light was examined using beta -limit dextrin. A sharp increase in activity of this enzyme was observed after 2 days in both sets of plants; in the dark it increased to 540 IDC units/cotyledon after 10 days, then decreased abruptly, whereas in light-grown plants it increased to a plateau of 260 units on the 6th day. Excised cotyledons incubated without GA3 were able to synthesize some alpha -amylase (74 units), but with 500 ng GA3/ml there was a 3-fold increase to 208 units, a level corresponding with that found after 4 days in cotyledons of intact etiolated seedlings. Results indicated that the endogenous balance between growth substances and inhibitors regulating mobilization of cotyledon food reserves is controlled by embryonic growth and light.