Abstract: Revision on meteorological indices of frost disaster for Camellia sinensis can provide more scientific and proper criteria for the prevention and evaluation of the spring frost disaster. Taking 4 main varieties of C. sinensis in Zhejiang Province as study objects, changes of physiological indices in C. sinensis leaves were observed in 6 groups of different low temperature and duration time in artificial climate box (15 ℃/3 ℃, 12 ℃/2 ℃, 10 ℃/1 ℃, 10 ℃/0 ℃, 10 ℃/-1 ℃, 10 ℃/-2 ℃, with higher temperature lasting 12 h while lower lasting 4 h; 25 ℃ as control). Thereby, semilethal temperature of C. sinensis was determined by the application of Logistic function. The results showed that happening of frost disaster was closely related with low temperature intensity and duration, and the semilethal temperatures of the 4 varieties were Fortin white tea (-1.5 ℃) < Wuniuzao (-1.3 ℃) < Jiukeng (-1.2 ℃) < Longjing43 (-0.7 ℃). Accordingly, a new rating standard of frost disaster for C. sinensis was put forward by combining historical disaster with hourly temperature data of tea gardens. The rating standard included three parts, namely meteorological index, symptom and frost damage percentage of new spring shoots. Among them, the meteorological index referred to hourly minimum air temperature and its duration during the growth period of C. sinensis. The validation by two frost disasters in the spring of 2013 indicated that the monitoring results of the new rating standard were consistent with the actual situation, with 41.7% higher percentage of accuracy than that of the original standard. This study provides important technique support for quantitative tea meteorological services.

Key words: Rhodiola gannanica, endangered, reproductive ecology.