Ent-Kaurene biosythesis is enhanced by long photoperiods in the long-day plants Spinacia oleracea L. and agrostemma githago L
- Michigan State Univ., East Lansing (United States)
The effect of photoperiod on ent-kaurene biosynthesis was determined in the long-day (LD) plants spinach (Spinacia oleracea L.) and Agrostemma githago L. Further metabolism of ent-kaurene was blocked by application of the growth retardant tetcyclacis, and ent-kaurene accumulation was measured by isotropic dilution using gas chromatography-selected ion monitoring (GC-SIM). In spinach, the rate of ent-kaurene accumulation in shoots grown under LD conditions was 3 times higher than in shoots grown under short-day (SD) conditions. ent-Kaurene also accumulated in fully expanded leaves, but at a lower rate than in shoots (15 and 55 pmol g[sup [minus]1] dry weight h[sup [minus]1], respectively). In Agrostemma, ent-kaurene accumulated at a rate 2.5 times higher in plants grown under LD conditions than in those grown under SD conditions. In spinach, enhanced ent-kaurene accumulation was detectable after 1 long day, and with exposure to additional long days, the rate of ent-kaurene accumulation increased further. Conversely, when plants were exposed to LD conditions and then to Sd conditions, the rate of ent-kaurene accumulation decreased. Following tetcyclais application, ent-kaurene accumulation was observed in all parts of spinach that were analyzed, but there were large quantitative differences between organs of different ages. As the leaves matured, ent-kaurene biosynthesis declined. Petioles accumulated more ent-kaurene than the corresponding leaf blades. It is concluded that stimulation of ent-kaurene biosynthesis by LD conditions leads to higher rate of gibberellin biosynthesis, which is essential for stem elongation in rosette plants. 19 refs., 2 figs., 3 tabs.
- OSTI ID:
- 6589241
- Journal Information:
- Plant Physiology; (United States), Vol. 101:1; ISSN 0032-0889
- Country of Publication:
- United States
- Language:
- English
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