棉 花 学 报     Cotton Science     2009，21(6)：492-496

Physiological and Biochemical Characteristics of Main-stem Leaves among Three Cotton Genotypies with Varying High-temperature Tolerance
YUAN Xiao-ling^1，3，XIONG Ge-sheng²，DENG Jiang-ming¹，WU Feng¹，LIU Zhi^1*
(1.College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China; 2.Normal College of Science and Technology, Hunan Agricultural University, Changsha 410128, China; 3.Hunan Jinnong Seed Company Ltd ., Changsha 410128, China)

Abstract：A comparative investigation on the physiological and biochemical characteristics and their fluctuation in main stem leaf of cotton lines with different tolerance to high temperature stress was presented in the paper. The results showed that the leaf cell membrane thermo-stability (CMT) was significantly stronger in tolerant line HLY than susceptible line TS18 during the whole growth period and moderately susceptible line XYM68 at peak flowering and boll-setting stages. Of the three differentially tolerant lines, the proline content was different significantly with each other at all stages except for seedling, the soluble sugar content became significantly different at peak flowering and boll-setting stages, while there was nearly no change for dissolvable protein content during the whole developmental period. The chlorophyll content was higher in tolerant line HLY than susceptible counterparts XYM68 and TS18 at peak flowering and boll-setting stages and HLY owned the highest net photosynthetic rate at all of the four stages. The tolerant cotton line may be distinguished from susceptible ones by the CMT, proline, soluble sugar content and net photosynthetic rate traits in main stem leaf, which can be used as a measure of high temperature tolerance in cotton breeding program.
Key words：cotton；high-temperature stress tolerance；functional leaf on main stem；physiological
and biochemical characteristics      [Full Text, 2301KB]