东魁与荸荠种杨梅叶片春季光合特性比较

Comparison of leaf photosynthetic characteristics between two Chinese bayberry cultivars in spring season

春季田间条件下,以浙江省主栽品种东魁和荸荠种杨梅为试材,对其叶片光合特性、比叶重、叶绿素含量和碳水化合物含量等差异进行了比较研究。结果表明,东魁和荸荠种杨梅叶片的净光合速率日变化均为双峰型曲线,有明显的"午休"现象;东魁杨梅净光合速率、水分利用率和气孔导度的日均值显著高于荸荠种杨梅,而日平均蒸腾速率显著低于荸荠种杨梅;午间光合速率和胞间CO2浓度下降,变化趋势一致,气孔限制值升高,表明光合速率午间降低主要是受气孔限制因素影响。东魁杨梅的叶绿素含量和叶绿素a/b略低于荸荠种杨梅,但无显著差异,而荸荠种杨梅叶片的比叶重、可溶性糖、还原糖和淀粉含量都明显高于东魁杨梅,且差异显著。

Under the field conditions in spring season, diurnal changes in photosynthetic parameters, specific leaf dry weight, contents of chlorophyll and carbohydrate in leaves were compared between Dongkui and Biqi Chinese bayberry with Li-6400 photosynthetic instrument. The results showed that their diurnal changes of net photosynthetic rate （Pn） exhibited dual-peak curves because of midday depression. Pn, water use efficiency （WUE） and stomatal conductance （Gs） of Dongkui cultivar were significantly higher than those of Biqi, but its transpiration rate （Tr） was significantly lower. The increase in stomatal limitation （Ls） and the decrease in intercellular CO2 concentration （Ci） accompanied a reduction of Pn at noon indicated that the depression of photosynthetic rate was mainly due to the stomatal limitations. The contents of chlorophyll and Chl （a/b） of Dongkui were slightly lower than those of Biqi. The specific leaf dry weight, contents of soluble sugar, reducing sugar and starch of Biqi cultivar were significantlyhigher than those of Dongkui cultivar.