锌胁迫对两种柑橘幼苗光合特性日变化及其相关性的影响

通过砂培试验,采用C I-340型便携式光合测定系统研究了不同锌处理（0.05mg/L Zn为对照,0.5mg/L Zn为锌过量,0mg/L Zn为锌缺乏）对‘不知火’和‘椪柑’幼苗叶片光合特性日变化及其相关性的影响。结果表明,在锌胁迫条件下,‘不知火’叶片的净光合速率（Pn）日变化呈单峰曲线,对照为双峰曲线,而‘椪柑’与对照呈现相似的单峰型变化,且锌胁迫下两者平均的Pn均显著低于对照。简单相关分析表明,‘不知火’在锌胁迫下叶片Pn与光合有效辐射（PAR）、蒸腾速率（Tr）均呈显著的正相关,其对照Pn与各因子之间并无显著相关性,各锌处理下的‘椪柑’叶片Pn均与Gs呈显著正相关。逐步多元回归的分析结果与简单相关分析结果存在出入。还就锌胁迫对两品种柑橘的光合特性及其相关性的影响进行了讨论。

Effect of Zn stress on photosynthetic characteristic and their correlation of the two varieties of citrus

The sand culture experiment was conducted by using portable photosynthesis system CI-340.The effects of diurnal variations of photosynthetic characteristics and their correlations of ＇shiranuhi＇（Citrus reticulata ×（C.reticulata×C.sinenesis）） and ponkan′（Citrus reticulate Blanco） seedling leaves were investigated under different zinc treatments（0,0.05 and 0.5 mg/L were considered as Zn deficiency treatment,control and Zn excess treatment,respectively）.The results showed that the net photosynthetic rate（Pn） of shiranuhi′ presented a one-peak curve under Zn stress,but double-peak curve was found under control,as to ponkan′,similar double-peak curves were observed under control and Zn stress treatments.Furthermore,the average Pn of the two citrus was significantly lower under Zn stress than control.Simple correlation analysis showed that the Pn of shiranuhi′ under Zn stress was positively correlated with photosynthetic active radiation（PAR） and transpiration（Tr）,while the Pn of control had no significant correlation with relative factors.Whereas the Pn of ponkan′ under Zn stress and control was all positively corelated with stomatal conductance（Gs）.There existed a few differences between stepwise multiple regression analysis and simple correlation analysis results.The effects of Zn stress on the photosynthetic characteristics and their correlations of the two varieties of citrus were discussed.