通过设置播期试验使棉纤维加厚发育过程(铃龄25,50d)处于不同的温度条件下,研究低温对棉花纤维比强度形成的内在生理机制影响,为采取调控措施解决目前棉花(Gossypium)生产中存在的晚熟劣质问题提供理论依据。两年试验结果表明:棉纤维加厚发育期24.0℃左右的日均温是高强纤维形成的最佳温度,其内在生理机制表现为棉纤维蔗糖合成酶活性最高,β-1,3-葡聚糖酶活性最低,纤维素的累积量和累积速率均明显高于其它低温条件,纤维超分子结构取向参数角较小,处于优化状态,最终表现为纤维比强度亦最大;低于21.0℃时即对棉纤维加厚发育相关酶活性产生明显影响,纤维比强度降低。当温度降到15.0℃左右时,棉纤维蔗糖合成酶活性显著降低,而β-1,3-葡聚糖酶活性显著升高,同时纤维素累积量和累积速率均显著降低,纤维超分子结构取向参数角明显宽化,棉纤维不能正常发育,不利于高强纤维的形成(铃重仅为3.22g,纤维比强度仅为15.73cN·tex^-1)。
It is believed that the thickening process of fiber in cotton is affected by low temperature as late seeding often produces poor quality cotton. Effects of temperature on the physiological mechanisms of cotton fiber strength forming processes were studied to determine whether low temperature was responsible for the bad quality of late maturing cotton by regulating temperature during growth. The results of a 2-year experiment showed that mean daily temperature of 24.0 ℃ during the bell stage between 25 to 50 days formed highstrength cotton fiber. Cotton fiber sucrose synthetase activity was the highest, β-1,3-glucanase activity was the lowest, and cellulose accumulation and accumulation rates were the highest at this temperature. When mean daily temperature was lower than 21.0 ℃, enzyme activity related to cotton fiber thickening development was reduced resulting in lower fiber strength. When mean daily temperature were around 15.0 ℃, the fiber sucrose synthetase activity evidently fell, β-1,3-glucanase activity increased, and quantity of cellulose accumulated and accumulation rate evidently declined. In this case, cotton fiber development was abnormal, and bell weight was only 3.22 g, and fiber strength only 15.73 cN·tex^-1.