科研之友
微信
新浪微博
Facebook
分享链接
摘要
Sorghum [Sorghum bicolor (L.) Moench] is commonly grown in water-limited environments throughout the world. Plant traits could be useful allowing for early-season water conservation so that more water is available for use later in the season when drought is most likely to develop. One trait that might result in early-season water conservation is the expression of a limited-transpiration trait defined as a limitation on further increases in transpiration rate (TR) under high vapor pressure deficit (VPD) conditions. The objective of this study was to compare the expression of the limited-TR trait measured for nine sorghum genotypes under both controlled chamber and field conditions. In the growth chamber, plant TR was measured over a range of imposed VPD to provide a direct measure of plant transpiration under high VPD. In the field, stomatal conductance (g(s)) was measured over the daily cycle, which resulted in a range of ambient VPD. A decrease in g(s) under high VPD was evidence of the limited-TR trait. This study identified three sorghum genotypes (DKS 36-06, DKS 44-20, and DKS 54-00) that did not show any limitation on water loss at high VPD in either the greenhouse or field. On the other hand, four genotypes (BTX 2752, SC 599, SC 982, and B 35) exhibited the limited-TR trait in the growth chamber with breakpoints in response to VPD at values of 2.33 kPa and above. These four genotypes also expressed a breakpoint in g(s) in response to increasing VPD in the field. Two genotypes (TX ARG 1, TX 436) that differed between the growth chamber and field showed consistency in response on close examination of the field results. The overall general correspondence within genotypes between the controlled chamber and the field in expression or lack of expression of a breakpoint in response to increasing VPD demonstrated the possibility of selecting genotypes for the TRlim trait under differing environmental conditions.
- 出版日期2014-3
