油茶无性系果实生长期光合特性研究

摘要

在油茶果实快速生长期7月,对XL67、XL1和CK 3个产量不同的油茶无性系的叶片净光合速率(Pn)、蒸腾速率(Tr)、水分利用效率(WUE)等日变化及光合—光响应曲线进行了测定.结果表明:XL67和CK的Pn日变化曲线呈“单峰型”,而XL1为“双峰型”,不同无性系峰值的出现时间及峰值的大小不同,XL67和CK存在光合“午休”现象.XL67、XL1和CK的Pn分别为6.97、6.30和5.72 μmol·m-2·s-1,3个无性系之间叶片的Pn差异显著.3个无性系叶片的Tr的日变化曲线均为“单峰型”,WUE的日变化曲线均为“U”型；3个无性系的最大净光合速率为9.79～14.20 μmol·m 2·s-1,光饱和点为409～540 μmol·m-2·s-1,光补偿点为58～82 μmol·m-2·s-1；采用逐步回归分析方法,筛选出了影响3个无性系叶片Pn的主导因子.%In July, during the rapid-growth period of fruit of oil-tea camellia (Camellia oleifera), diurnal changes of net photosynthetic rate(Pn), transpiration(TV), water use efficiency (WL/E) of three clones (XL67,XL1 and CK) were measured comparatively with LI-6400P portable photosynthetic system. The results showed that the diurnal changes of Pn of XL67 and CK were in unimodal curves, but that of XL1 was in a bimodal curve. Different peak value and occurring time were different ambng the clones tested. "Midday depression" phenomenon of photosynthesis was observed in all clones. The values of Pn of XL67, XL1, and CK were 6. 97, 6. 30 and 5. 72 fimol ? M-2 ? S-1 , respectively, and there were significant differences between them. Diurnal changes of Tr presented as unimodal curve while diurnal changes of WUE presented as a "U" curve. The maximun net photosynthetic rates of three clones were 9. 79 to 14. 20 μmol ? M-2 ? S-1, the light saturations of three clones were 409 to 540 μmol ? M-2 ? S-1, and the light compensation points of three clones were 58 to 82 μmol ? M-2 ? S-1, Main factors which influenced Pn were analysed by multivariate stepwise regression.