以在自然生长条件下不能开花的长沙藤蕹为试材，采用迁光的方法测定长沙藤蕹的临界光周期、限界性诱导光周期
和幼龄期。结果表明：藤蕹的临界光周期为12 h 光照/12 h 黑暗，限界性光周期为16 d，幼龄期在4 片真叶时结束。当光周
期暗期持续长度达到13 h 时，更有利于长沙藤蕹的花芽分化；当诱导光周期少于限界性光周期时，已分化的花芽会发生逆转，
说明长沙藤蕹是一种严格的专性短日照植物。
Taking unable blossom Changsha water spinach（Ipomoea aquatica）under natural growth
condition as test material，this paper measured the critical photoperiod，limited inductive photoperiod and juvenile
phase of Changsha water spinach by light transfer method．The results showed that the critical photoperiod of
Changsha water spinach was 12 hours light/12 hours dark，limited inductive photoperiod was 16 days，and the
juvenile phase of Changsha water spinach would terminate at 4-leaf stage．Additionally，when the dark period of
photoperiod sustained to 13 hours，it was more conducive to the flower bud differentiation in Changsha water spinach．
While the differentiated flower bud would be reversed，if the induced photoperiod was less than limited inductive
photoperiod．These results indicated that Changsha water spinach was strictly an obligatory short-day plant.
