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Effects of gibberellic acid on patterns of carbohydrate distribution and acid invertase activity in Phaseolus vulgaris
Author(s) -
Morris David A.,
Arthur Edwin D.
Publication year - 1985
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1985.tb02392.x
Subject(s) - plant stem , phaseolus , gibberellic acid , invertase , sucrose , hypocotyl , biology , botany , elongation , horticulture , chemistry , biochemistry , germination , materials science , ultimate tensile strength , metallurgy
The application of gibberellic acid (GA 3 ,10 μ M ) as a root drench to 16‐day‐old plants of Phaseolus vulgaris L. cv. Masterpiece stimulated growth of the stem internodes and reduced root growth. GA 3 treatment did not affect the export of 14 C from a primary leaf to which [ 14 C]‐sucrose was applied, but greatly increased upward translocation to the elongation region of the stem at the expense of transport to the hypocotyl and root system. The observed changes in the patterns of growth and [ 14 C]‐labelled assimilate distribution were correlated with an increase in the specific activity of acid invertase in the elongating stem internodes and a decrease in invertase activity in the hypocotyl and root. Sucrose concentration in the elongating internodes fell substantially after treatment with GA 3 while the concentration of hexose sugars increased. We suggest that by stimulating acid invertase synthesis in the elongating internodes, GA 3 acts to establish a more favourable sucrose gradient between these sinks and source leaves. Under source‐limiting conditions this, in turn, will lead to a reduced rate of assimilate translocation to competing sinks in the root system.