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A rhythm in the flowering response of photoperiodically‐induced Pharbitis nil to agents affecting cytosolic calcium and pH
Author(s) -
Friedman Haya,
Goldschmidt Eliezer E.,
Spiegelstein Hanna,
Halevy Abraham H.
Publication year - 1992
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.1399-3054.1992.tb05263.x
Subject(s) - egta , pharbitis nil , photoperiodism , period (music) , calcium , flower induction , botany , chemistry , rhythm , darkness , phytochrome , horticulture , biophysics , biology , zoology , medicine , red light , physics , organic chemistry , acoustics
Previous work with modulators of Ca 2+ and pH has indicated that elevated levels of cytoplasmic Ca 2+ and pH are required during the first 4‐5 h of the dark period for successful floral induction in Pharbitis nil Chois cv. Violet. In the present study we further examined the effect of modulators of Ca 2+ and pH by supplying them at various times prior to the inductive dark period. Peaks of inhibition by the Ca 2+ chelator, EGTA, were observed in seedings treated 8, 18‐and 34 h before the start of the dark period. When seedlings of slightly different ages (within one diurnal cycle) were treated with EGTA, maximum inhibition was always obtained in plants treated 8 h before the start of the dark period. Peaks of inhibition by the acidifying agents, salicylic acid and Na‐propionate, were observed at ‐2 to ‐6 h and at ‐10 to ‐ 14 h. Treatment with the alkalizing agent, trisodium citrate, enhanced the flowering response with maximum enhancement at ‐6 to ‐8 h and at ‐ 18 to ‐ 20 h. We hypothesize that treatment with modulators starts an oscillation in endogenous levels of Ca 2+ and pH. The levels of Ca 2+ and pH prevailing at the commencement of the inductive dark period will influence the ability of the plant to perceive or to respond to the photoperiodic induction.