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Galactose‐induced Ethylene Evolution in Mung Bean Hypocotyls: A Possible Mechanism for Galactose Retardation of Plant Growth
Author(s) -
COLCLASURE G. CRAIG,
YOPP JOHN H.
Publication year - 1976
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.1399-3054.1976.tb03974.x
Subject(s) - hypocotyl , auxin , ethylene , galactose , phaseolus , methionine , biochemistry , chemistry , abscission , amino acid , biology , botany , gene , catalysis
Galactose has long been known to inhibit growth in certain plant systems and more recently to promote abscission. These same systems are similarly affected by ethylene. The mung bean ( Phaseolus aureus Roxb.) hypocotyl system was employed to ascertain whether the inhibitory effects of galactose might be regulated through ethylene. Galactose alone (at 10 and 100 m M ) of the many carbohydrates tested elicited high rates of ethylene evolution (1.5–4.0 nl/g fresh weight x h) as determined by gas chroma‐tography. Hook opening, pigment formation, and hypocotyl elongation were inhibited by this resultant ethylene. Galactose and auxin were found to act synergistically with respect to ethylene induction. Use of an auxin antagonist and auxin transport inhibitor revealed that galactose‐induced ethylene formation is auxin dependent. Time course studies indicate that this effect may be auxin‐sparing. Methionine appears to be the substrate of galactose‐induced ethylene. since a methionine antagonist [L‐2‐amino‐4‐(2′‐amino ethoxy)‐trans‐3‐butenoic acid] abolished the induction. Potential interrelationships between galactose and ethylene synthesis are discussed.