PHOTOPERIOD INDUCED CHANGE IN PHYLLOTAXIS IN XANTHIUM

摘要: Photoperiodic floral induction in Xanthium, achieved by subjecting the plants to two long nights, is accompanied a transient change of phyllotaxis from (2, 3) contact parastichy pattern vegetative plants, (3, 5) during transition. To specify phyllotaxis, parameters were estimated transverse sections apical buds control and treated plants: divergence angle, a, plastochron ratio, a. The ratio decreased progressively transition reproductive state growth, = 1.48 initially 1.15 six days after beginning induction. angle was not altered This interpreted as relative positioning leaf primordia on transitional apex. appears be identical with previously described long-term Xanthium brought about treatment gibberellic acid.