Premium
PHYLLOTACTIC CHANGE INDUCED BY GIBBERELLIC ACID IN XANTHIUM SHOOT APICES
Author(s) -
Maksymowych Roman,
Erickson Ralph O.
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.tb07602.x
Subject(s) - phyllotaxis , gibberellic acid , primordium , biology , xanthium , botany , shoot , meristem , divergence (linguistics) , gibberellin , genetics , linguistics , philosophy , germination , gene
Gibberellic acid (GA) treatment of vegetative shoots of Xanthium leads to a change in phyllotaxis as diagnosed in transverse sections of apical buds. A method of analysis is proposed for estimating the phyllotactic parameters, the plastochron ratio, a , and the divergence angle, α, from measurements of the angular and radial positions of leaf primordia in sections. GA treatment significantly decreases the plastochron ratio, a , from 1.35 in controls, to 1.19 in GA‐treated plants, as shown by an analysis of variance, but has no significant effect on the divergence angle. The estimates of a and α are compared with the parameters of theoretical phyllotaxis models, leading to the designation (2, 3) for controls, and (3, 5) for GA‐treated plants, where the integers 2, 3, and 5 designate sets of contact parastichies. The change in a is interpreted as indicating a change in the relative position at which leaf primordia are initiated in the apical meristem, and this effect is discussed in relation to theories of leaf initiation.