低温胁迫对茶树叶片生理特性的影响

Effects of low temperature stress on physiological characteristics of tea leaves(Camellia sinensis L.)

【目的】研究低温胁迫对茶树叶片中主要渗透调节物质、叶绿素含量(以叶绿素含量指数(CCI)表征)及其荧光参数Fv/Fm值的影响,探讨茶树对低温胁迫的响应特点,为茶树的引种及抗寒栽培提供理论依据。【方法】以"舒茶早"和"乌牛早"的当年生枝条为材料,对其分别进行-6、-9、-12、-15和-18℃的低温处理,以未经低温处理的枝条为对照,研究逆境条件下,茶树叶片的相对电导率、脯氨酸、可溶性蛋白、可溶性糖、叶绿素含量及Fv/Fm值的变化,并根据相对电导率计算半致死温度(LT50)。【结果】-6℃处理下,"舒茶早"和"乌牛早"的相对电导率与对照均无显著差异,之后随着温度的降低相对电导率显著增大。"舒茶早"和"乌牛早"叶片中的脯氨酸、可溶性蛋白和可溶性糖含量随温度的降低均呈先升后降的变化趋势,且"舒茶早"叶片中3个指标的含量均明显高于"乌牛早",但"舒茶早"和"乌牛早"响应低温胁迫的温度范围有所不同。"舒茶早"叶片中的叶绿素含量远高于"乌牛早",温度低于-9℃时,2种茶树叶片叶绿素含量和Fv/Fm值均明显降低。"舒茶早"和"乌牛早"的LT50分别为-17.3和-16.7℃。【结论】在低温胁迫过程中,与茶树抗寒相关的生理指标均发生显著变化;-17℃左右低温会对茶树造成严重的生理伤害,栽培上应注意预防这种极端的低温冻害。

【Objective】 The reaserch on effects of differing low temperature stress on main osmotic adjustment substances,chlorophyll content（chlorophyll content index） and fluorescence paramerter Fv/Fm of tea leaves was performed to study the response of tea plants to low temperature stress and provide a basis for tea introduction and cultivation.【Method】 One-year-old detached branches of ’Shuchazao’ and ’Wuniuzao’ were treated under-6,-9,-12,-15 and-18 ℃,respectively,and the changes of relative conductivity,proline,soluble protein,soluble sugars,chlorophyll content and Fv/Fm of tea leaves under stress conditions were measured with untreated materials as control.Then the semilethal temperature（LT50） was calculated based on relative conductivity.【Result】 The results showed that there was no significant difference in relative conductivity between control and treatment under-6 ℃ stress,but the relative conductivity was remarkably increased with the decrease of temperature.As temperature decreased,the content of proline,soluble protein,soluble sugars all ascended first and then decreased,and these indexes of ’Shuchazao’ exceeded significantly those in ’Wuniuzao’.However,temperature range in responsive to low temperature stress of these indexes was different between ’Shuchazao’ and ’Wuniuzao’.’Shuchazao’ had a remarkable higher content of Chlorophyll than ’Wuniuzao’.When the temperature was below-9 ℃,chlorophyll content index and Fv/Fm decreased obviously.LT50 of ’Shuchazao’ and ’Wuniuzao’ were-17.3 and-16.7 ℃ respectively.【Conclusion】 The physiological indexes related to cold-resisitance of tea plant all changed significantly under low temperature stress,and tea plant would suffer serious physiological harm at-17 ℃,which should be on guard on tea cultivation