Effects of Low Temperatures on the Protective Enzyme Activity of Rice at Booting Stage

Different rice varieties have different reactions to temperature stress,so it is very important to understand the cold resistant mechanism. We took the rice variety "Chujing-26" as test materials to study the physiological and biochemical effect under two different low temperature treatments treatment 1: (20 ℃(06:00-18:00) / 12 ℃ (18:00-06:00), treatment 2: (18 ℃) (06:00-18:00)/5 ℃ (18:00-06:00), using normal temperature 28 ℃(06:00-18:00)/25 ℃(18:00-06:00) as control. The result showed that glutathione reductase (GR) activity increased greatly under treatment 1 while other enzymes activity showed little change. Under treatment 2, the activity including peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT), superoxide dismutase (SOD) increased more than control. The result of pollen fertility test showed that treatment 2 was more severe than treatment 1. At the same time, determination of chlorophyll fluorescence parameters of Fv/Fm also supported that treatment 2 was more severe than treatment 1, but neither treatment destroyed rice photosynthetic apparatus. The experimental results supported the adaptability of Chujing-26 to low temperature change, and the antioxidant enzyme activities play an important role.