贵州茶树主栽品种福鼎大白茶冷害指标研究

Cold-injury Indicator for Camellia sinensis cv. Fuding-dabaicha in Guizhou Province

【目的】探明贵州茶叶主栽品种福鼎大白茶的低温冷害指标,为精准茶叶气象指数保险和茶叶农业气象服务提供科学指导。【方法】利用人工气候室模拟贵州低温冷害天气过程,测定茶叶不同低温冷害过程中生理指标以反映茶叶低温环境下的生长状态;拟合细胞伤害率与低温胁迫之间的Logistic函数关系,确定茶树生长的低温半致死温度,以量化不同低温冷害天气过程中茶叶的冷害指标。【结果】随低温程度的加重,SOD活性大致呈上升趋势,MDA含量大致呈先升高后下降趋势,相对电导率R呈持续上升趋势;低温冷害持续日数不同,对应低温半致死温度不同,低温持续时间越长低温半致死温度越高,低温冷害天气持续3、5和7 d时,低温半致死温度分别为1.5、1.8和2.6℃。【结论】福鼎大白茶冷害生长响应特征与低温冷害程度和持续天数密切相关:最低温度3℃以下的低温危害比3℃以上大;低温过程持续7 d的低温危害比持续3、5 d时严重;低温半致死温度随冷害持续时间的延长而升高,因此低温冷害指标的制定应依据当地倒春寒冷害气候特征进行量化。

【Objective】A cold-injury index for Camellia sinensis cv.Fuding-dabaicha,the major tea cultivars in Guizhou,was established to provide the meteorological information for precision insurance actuary and agro services on the crop.【Method】Physiological indices that reflect the growth of the tea plants under simulated low-temperatures in an artificial climate chamber were monitored.Semi-lethal temperature of the plants by cold stress was mathematically determined on a logistic function between the rate of injured cell and treatment temperature.【Result】With the lowering temperature,the physiological responses of the plants showed a gradually increased SOD activity,initially raised and then declined MDA,and continuously increased relative electric conductivity.The semi-lethal temperature of the plants differed depending upon the duration of cold treatment.The longer the plants were exposed to the chill,the higher the semi-lethal temperature became.When the cold lasted for 3 d,5 d,and 7 d,the semi-lethal temperatures rose to 1.5℃,1.8℃,and 2.6℃,respectively.【Conclusion】The growth responses of C.sinensis under low-temperature closely related to severity as well as duration of the exposure.At a temperature below 3℃,the harm imposed on the plant was more serious than above 3℃.And,a severe coldinjury would likely to incur if the treatment lasted for 7 days than 3 d or 5 d on the plants.The semi-lethal temperature of a plant increased with prolonged cold exposure.Thus,the cold-injury index should be applied with a consideration of local climatic conditions.