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Inhibitory and promotive effects of gibberellic acid on floral initiation and development in Poa pratensis and Bromus inermis
Author(s) -
Heide O. M.,
Bush M. G.,
Evans L. T.
Publication year - 1987
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.1399-3054.1987.tb04298.x
Subject(s) - gibberellic acid , biology , gibberellin , flower induction , inflorescence , botany , bromus inermis , poa pratensis , photoperiodism , elongation , horticulture , poaceae , germination , materials science , ultimate tensile strength , metallurgy
Flowering in Poa pratensis L. cv. Holt and Bromus inermis Leyss. cv. Manchar requires exposure to short days (SD) for primary induction to occur, followed by long days (LD) to allow the inflorescence to develop. Weekly sprays with gibberellic acid (GA 3 ) during primary induction inhibited flower initiation in both P. pratensis and B. inermis . With 10 −4 M GA 3 flowering of P. pratensis was suppressed even after an induction period of 10 weeks. Since both GA 3 and non‐inductive LD conditions greatly stimulate leaf elongation, the degree of primary induction was closely negatively correlated with plant height (leaf sheath and blade length) at the end of the induction period. GA 3 application or the interpolation of LD during SD induction were most inhibitory during the later middle part of the SD period, whereas they were stimulatory near the beginning or immediately before the SD period. We suggest that changes in the portfolio or levels of endogenous gibberellins mediate photoperiodic control of growth and floral initiation in these plants. However, GA 3 sprays could not substitute for LD in causing heading and culm elongation in SD induced plants of the two species. The results are discussed in the light of results with other plants with dual floral induction requirements.