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Interaction between P fr and growth substances in the germination of light‐requiring Kalanchoë seeds
Author(s) -
Dedonder A.,
Rethy R.,
Frederieq H.,
Greef J. A.
Publication year - 1983
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.1399-3054.1983.tb04235.x
Subject(s) - phytochrome , gibberellic acid , gibberellin , abscisic acid , antagonism , germination , irradiation , chemistry , botany , red light , horticulture , biophysics , biology , biochemistry , physics , receptor , nuclear physics , gene
Seeds of Kalanchoë blossfeldiana Poelln. cv. Feucrblüte, incubated on gibberellic acid, become very light‐sensitive through a synergism between the far‐red absorbing form of phytochrome and the growth substance, which results in high physiological activity of short far‐red (FR) exposures. On 2 × 10 ‐3 M gibberellic acid (GA 3 ), one saturating FR pulse is somewhat more effective than one saturating red light (R) irradiation. Fluence‐response curves for R and FR confirm this observation. At lower GA 3 concentrations, this difference disappears and the effects of one saturating R and FR pulse decrease in an identical way with the GA 3 concentration. When two saturating irradiations, separated by 24 h are given, the effect of FR falls off faster than that of R at low GA 3 concentrations. Consequently, the second irradiation must have a different impact in comparison with the first one. Of the other growth substances tested, only a mixture of gibberellins A4 and A 7 had an analogous, still more pronounced effect than GA 3 . Abscisic acid (ABA) inhibits the phytochrome‐mediated germination of Kalanchoë , both in the absence and presence of GA 3 . An antagonism between ABA and GA 3 was demonstrated.