高温对北高丛蓝莓叶片气体交换及叶绿素荧光参数的影响

Effects of high temperature on leaf gas exchange and chlorophyll fluorescence parameters of the north highbush blueberry

以2年生北高丛蓝莓(Vaccinium corymbosum L.)3个优良品种"蓝丰"、"公爵"和"布里吉塔"的苗木为实验材料,利用人工气候箱控制生长温度,探讨不同温度处理对北高丛蓝莓叶片气体交换和叶绿素荧光参数的影响。结果表明:随着温度升高,3个品种叶片的净光合速率(P_n)、气孔导度(G_s)、蒸腾速率(T_r)和水分利用效率(WUE)均先升高后降低,最大值随品种的不同而发生变化;3个品种的细胞间CO_2浓度(C_i)均一致性地呈现相反的变化趋势,30和35℃高温使Ci降低,而40℃高温又导致了Ci升高;相对电导率和叶绿素荧光参数F_v/F_m的测定结果表明,30和35℃高温对北高丛蓝莓叶片结构和功能的影响非常有限,40℃高温却导致其细胞膜结构的破坏;40℃高温对光系统Ⅱ反应中心及其电子传递链的结构造成了不可逆的严重损伤;不同北高丛蓝莓品种的抗高温能力存在很大差异,"布里吉塔"最强,"蓝丰"次之,"公爵"最弱。研究结果有助于深入理解温度对北高丛蓝莓产生影响的潜在机理,为蓝莓耐高温品种选育和引种工作提供理论依据。

We examined the effects of temperature on the leaf gas exchange and chlorophyll fluorescence parameters of two-year-old seedlings of three north highbush blueberry cultivars（ Bluecrop,Duke,and Brigitta） in growth chambers. The results showed that the net photosynthetic rate（ P_n）,stomatal conductance（ G_s）,transpiration rate（ T_r）,and water use efficiency（ WUE） of the three blueberry cultivars shared bell-shaped curves with growth temperature,although their maximum values varied with the cultivars. Compared to 25 ℃,intercellular CO_2concentrations（ C_i） of the three cultivars decreased at 30 and 35 ℃,but increased at 40 ℃. Moreover,the results from electrolyte leakage and F_v/ F_m demonstrated that the temperatures of 30 and35 ℃ had little effects on the leaf structure and function,but the temperature of 40 ℃ damaged the cellular membrane structure of blueberry leaves. The temperature of 40 ℃ resulted in severely irreversible damages to both the PSⅡ reaction center structures and electron transport chains. In addition,the three blueberry cultivars had different abilities in resisting heat stress with the order of Brigitta Bluecrop Duke. These results may be helpful for further understanding the mechanisms of temperature on the north highbush blueberry cultivars,and provide basis for selection and introduction of heat tolerance cultivars.