不同梨品种叶片光合特性及其影响因素研究

Studies on Leaf Photosynthetic Characteristics and Affecting Factors in Different Pear Cultivars

以莱阳茌梨、栖霞小香水梨和黄县长把梨为试材,应用CIRAS-II便携式光合测定仪,研究了光合有效辐射、叶龄、叶位和方位对不同梨品种叶片光合特性的影响。结果表明:晴天条件下,所有供试梨品种的净光合速率(Pn)日变化呈不对称双峰曲线;阴天条件下表现为单峰曲线。正面受光叶片的Pn显著高于背面受光叶片。此外,光合速率还受到叶位和叶龄的影响,相同方位外围新梢叶片的净光合速率以基部第7-9叶片最高,且拟合曲线呈抛物线状。Pn随叶龄的增加呈“低—高—低”的趋势,30 d叶龄的莱阳茌梨和栖霞小香水梨叶片具有最大的Pn,而黄县长把梨是40d叶龄。

The effects of PAR, leaf age, leaf position and localization on photosynthetic characteristics in different pear cultivars were determined with CIRAS - Ⅱ portable photosynthesis system under field condition. The results showed that the daily changes of net photosynthetic rate （Pn） in three different cultivars were two - peak pattern curves in sunny day; however, the daily Pn presented one - peak pattern curves in cloudy day, and the leaves with upper surface radiated had higher Pn compared with leaves with back surface radiated. On the other hand, the results also indicated that the leaf Pn on annual new shoots from bottom to tip increased at the beginning and then decreased, and accorded with parabola curve. The leaves from 7th to 9th located from bottom had highest Pn in all cultivars. Moreover, the leaf Pn presented ＂low-high - low＂ tendency with the increase of leaf ages, and the leaf with 30 days - old showed the highest Pn in both Laiyang Chili and Qixia Xiaoxiangshui pear, but 40 days - old in Huangxian Changba pear.