EFFECTS OF LOW TEMPERATURE ON PHYSIOLOGICAL MECHANISMS OF COTTON FIBER STRENGTH FORMING PROCESS

Abstract

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 boll stage between 25 to 50 days formed high_strength 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 boll weight was only 3.22 g, and fiber strength only 15.73 cN·tex~-1 .