The studies have been carried out to investigate the influences of daylength and temperature on the rest induction, the contents of endogenous hormones and nucleic acid for grapevines of `Concord´ (Vitis labrusca Linne), `Delaware´ (Vitis labruscana Bailey) and `Golden Queen´ (Vitis vinifera Linne) from 1984 to 1985.
For all 3 cultivars treated with combinations of different daylength and temperature, long day＋25℃ treatment showed no sign of rest, whereas short day＋15℃ gave the deepest rest compared with other treatments within respective cultivars, and the depth of rest was the deepest in `Concord´, intermediate in `Delaware´ and the shallowest in `Golden Queen´ cultivar. In the differences in rest between long day＋15℃ and short day＋25℃ treatments, `Concord´ showed deeper rest in short day than in long day condition, while `Golden Queen´ and `Delaware´ gave deeper rest at 15℃ than at 25℃ regimes.
In terms of endogenous hormones and nucleic acid of all 3 cultivars treated with combinations of different daylength and temperature, the contents of gibberellins (GA) and cytokinin in shoots and roots were the highest in long day＋25℃, and were the lowest in short day＋15℃ treatments. However, abscisic acid (ABA) content was the highest in short day＋l5℃, and was the lowest in long day＋25℃ treatment. The content levels of GA and cytokinin in grapevine shoots were higher in long day＋15℃ than in short day＋25℃ for `Concord´, whereas those were higher in short day＋25℃ than in long day＋15℃ treatment for `Delaware´ and `Golden Queen´. In contrast, the level of ABA content in shoots was lower in long day＋15℃ than in short day＋25℃ for `Concord´, whereas it was lower in short day ＋25℃ than in long day＋15℃ treatment for `Delaware´ and `Golden Queen´.
The auxin contents in shoots and roots of all 3 cultivars failed to show any constant responses to the treatments.
The amount of ethylene evolution from the shoots and roots of all 3 cultivars was the least in long day＋25℃ and the most in short day＋15℃ treatment.
The RNA contents 6 in grapevine were higher at 15℃ than at 25℃ treatment for all 3 cultivars, and daylength differences did not give any constant effects on their contents.
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