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PHOTOPERIOD INDUCED CHANGE IN PHYLLOTAXIS IN XANTHIUM
Author(s) -
Erickson Ralph O.,
Meicenheimer Roger D.
Publication year - 1977
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1977.tb11943.x
Subject(s) - phyllotaxis , xanthium , biology , primordium , botany , photoperiodism , divergence (linguistics) , apex (geometry) , meristem , shoot , biochemistry , linguistics , philosophy , gene
Photoperiodic floral induction in Xanthium , achieved by subjecting the plants to two long nights, is accompanied by a transient change of the phyllotaxis from the (2, 3) contact parastichy pattern of vegetative plants, to a (3, 5) pattern during the transition. To specify the phyllotaxis, two parameters were estimated from transverse sections of apical buds of control and treated plants: the divergence angle, α , and the plastochron ratio, a. The plastochron ratio decreased progressively during transition from the vegetative to the reproductive state of growth, from a = 1.48 initially to a = 1.15 six days after the beginning of induction. The divergence angle was not altered during the transition. This change in phyllotaxis is interpreted as a change in the relative positioning of leaf primordia on the transitional apex. This transient change appears to be identical with the previously described long‐term change of the phyllotaxis of Xanthium brought about by treatment of plants with gibberellic acid.