Endogenous gibberellins and stem growth as related to photoperiod in Silene armeria L
- Michigan State Univ., East Lansing (USA)
The early 13-hydroxylation gibberellin (GA) pathway operates in the long-day plant Silene armeria grown under both long-day (LD) and short-day (SD) conditions. Thus, induction of stem growth must be related to quantitative changes in GA pattern. Using GC-SIM-MS and GAs labeled with stable isotopes as internal standards, the levels of GA{sub 53}, GA{sub 19}, GA{sub 20}, and GA{sub 1} were measured in shoots and various organs of plants grown under different photoperiods. Exposure to 8 LD decreased the levels of GA{sub 53} and GA{sub 19}, and increased the levels of GA{sub 20} and particularly of GA{sub 1}; the latter GA accumulated to very high levels in expanding leaves and tips. When plants were exposed to LD, followed by SD, GA levels decreased, and the relative increases in stem length were correlated with the level of GA{sub 1} at the time the plants were returned to SD. These observations suggest that GA{sub 53}-oxidase, and probable also GA{sub 19}-oxidase, are under photoperiodic control. Furthermore, GA{sub 1} appears to be active per se in Silene in causing stem growth, since its level was always correlated with the degree of stem elongation.
- OSTI ID:
- 6611957
- Journal Information:
- Plant Physiology, Supplement; (USA), Vol. 89:4; ISSN 0079-2241
- Country of Publication:
- United States
- Language:
- English
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