LONG-TERM DEVELOPMENTAL CHANGES IN XANTHIUM INDUCED BY GIBBERELLIC ACID

摘要: One application of gibberellic acid (GA3) to Xanthium shoots resulted in an initial large stimulation, followed by inhibition, internode elongation. After presumed translocation the hormone from locus its stem apex several morphological changes were observed. There was a significant increase number mitotic figures apical meristem and twofold volume dome. With time, rate leaf production accelerated about 1.8 times. The phyllotaxis primordia initiated under influence GA3 changed (2, 3) contact parastichy pattern control shoot (3, 5) pattern. Final petiole length smaller than control, absolute lamina expansion decreased prolonged treatment. Gibberellic had pronounced effect on morphology. induced development lanceolate leaves instead typical deltoid leaves. reduction area coincided with 32 % average epidermal cells. Plastochron correlated anatomical during course development. MAKSYMOWYCH AND (1973) presented quantitative description vegetative pennsylvanicum as influenced (GA3). caused stimulation elongation, altered morphology, initiation. treated plants significantly reduced. Each response could be regulated increasing or decreasing concentration acid. In this paper we present additional information concerning long-range effects upon Increased rates initiation are associated enlargement dome seen To our knowledge is first report that treatment causes marked phyllotaxis. Morphological inhibition cell