Loper G M, Lapioli A M
Plant Science Research Division, Agricultural Research Service, United States Department of Agriculture, Bee Research Laboratory, Tucson, Arizona 85719.
Plant Physiol. 1972 May;49(5):729-32. doi: 10.1104/pp.49.5.729.
Alfalfa (Medicago sativa L.) plants acclimated to photoperiods of 18 hours light, 6 hour dark in plant growth chambers exhibited a daily cyclic pattern of floret volatile emanation with a maximum emanation of about 6.5 nanograms of hydrocarbons/floret.30 minutes. This maximum was reached about 6 to 8 hours into the light period. After 8 hours of light, emanation of volatiles decreased rapidly to less than 0.1 ng/floret.30 min even though light and temperature remained constant. Under continuous illumination, only a small increase of volatile emanation occurred during the following 24 hours. It appeared that a dark period was necessary to promote floret volatile emanation. Floret volatile emanation was drastically affected for at least 7 days following a photoperiod change. A photoperiod change caused 6-fold concentration oscillations every 2 hours. The results are interpreted on the basis of a very active floral metabolism controlled by photoperiodically induced rhythms.
在植物生长室中适应18小时光照、6小时黑暗光周期的紫花苜蓿（Medicago sativa L.）植株呈现出小花挥发物释放的每日循环模式，最大释放量约为6.5纳克碳氢化合物/小花·30分钟。这个最大值在光照期开始约6至8小时时达到。光照8小时后，即使光照和温度保持恒定，挥发物的释放也迅速降至低于0.1纳克/小花·30分钟。在持续光照下，在接下来的24小时内挥发物释放仅出现小幅增加。似乎黑暗期对于促进小花挥发物释放是必要的。光周期变化后，小花挥发物释放至少7天受到显著影响。光周期变化导致每2小时出现6倍的浓度振荡。这些结果是基于由光周期诱导节律控制的非常活跃的花代谢来解释的。
