Abstract
Six male sterile lines (MSLs) of ramie (Boehmeria nivea (L.) Gaud.) were grown in dark rooms under the photoperiods of 9.5h, 11h or 12.5h d-1 in spring and summer seasons (different environmental temperatures) to test their developmental response to photoperiod and temperature. The MSLs showed little difference in vegetative growth duration, but different reproductive growth development rates under the tested conditions. (Vegetative growth—— the growth of ramie plants during the period from shoot emergence to pistillate budding. Reproductive growth—— the growth of ramie plants during the period from pistillate budding to pistillate flower blooming.) Higher temperature (grown in summer) mainly accelerated vegetative growth, while the short photoperiod treatment accelerated the reproductive growth of the MSLs. Moreover, the short photoperiod treatment combined with higher temperature accelerated both the vegetative and reproductive growth of the MSLs. However, the effect of higher temperature decreased, or even disappeared with the photoperiod extension. The MSLs were divided into 5 photo-temperature response types, based on flower bud acceleration of the short photoperiod and the approximate temperature response index.
