3种李属红叶树种新叶和成熟叶光合作用日变化比较

目的]研究3种李属红叶树种新叶和成熟叶的光合作用日变化。方法]以红叶李（Prunusce Faslfem Ehrh．CV．atropurpurea Jacq）、红叶桃（Prunus persica f．atropurpurea Schneid）和美人梅（Prunus×bliriana‘Meirenmei’）为试材,测定了这3个树种成熟叶和新叶的净光合速率及其影响因子的日变化,并测定了其叶片中花青素和叶绿素的含量。结果]红叶桃与红叶李的成熟叶和3个树种的新叶净光合速率日变化曲线都呈双峰型,峰值分别出现在10：oo和16：00,新叶的第1个峰值比老叶提前2h出现,都在14：00出现“午休”现象;而关人梅成熟叶的净光合速率曲线为单峰型,在14：00达到最大,没有“午休”现象;3个树种内老叶与新叶的净光合速率日均值间无显著差异,树种间净光合速率日均值也无显著差异。3个树种新叶和成熟叶气孔导度日变化曲线与净光合速率日变化曲线一致。3个树种的成熟叶及红叶李的新叶蒸腾速率日变化曲线呈单峰型,在14：oo净光合速率值最小时达到了高峰值。叶面温度均以14：00最高,与净光合速率低谷对应。3个树种叶绿素含量间无显著差异;红叶桃花青素平均含量显著低于美人梅和红叶李。结论]该研究为这3个树种的栽培管理及其在园林配置中的应用提供了理论依据。

Comparison of Diurnal Changes of Photosynthesis between New Leaves and Mature Leaves among 3 Red-leaf Tree Species from Prune L.

Objective]The aim was to study the diurnal changes of photosynthesis between new leaves and mature leaves among 3 red-leaf tree species from Prune L.. Method]Diurnal changes of net photosynthetic rate and its influencing factors between new leaves and mature leaves among Prunus cerasifera Ehrh.cv. atropurpurea Jacq,Prunus persica f. atropurpurea Schneid and Prunus×bliriana 'Meirenmei' were determined,meanwhile contents of anthocyanins and chlorophyll in their leaves were measured. Result]Diurnal changes of net photosynthetic rates in mature leaves of red-leaf peach and prunus and new leaves of the 3 species expressed double-peak curves. The peak appared at 10:00 and 16:00,and the first net photosynthetic rate peak of new leaves appeared 2 h earlier than that of mature leaves,but they all had "midday depression" at 14:00. Net photosynthetic rate in mature leaves of Meirenmei expressed single-peak curves,which reached the maximum at 14:00,and "midday depression" didn't appear. There was significant difference in the net photosynthetic rates nither between new leaves and mature leaves of the 3 species nor among the 3 speices. Diurnal change curves of stomatal conductance between new leaves and mature leaves of the 3 species were similar to those of net photosynthetic rate. Transpiration rates of mature leaves of the 3 species and new leaves of red-leaf prunus expressed single-peak curves,which reached peak when net photosynthetic rate reached the minimum at 14:00. Leaf temperatures were all highest at 14:00,corresponding with low net photosynthetic rate. There was no significant difference in chlorophyll contents among the 3 species. Anthocyanidin content in red-leaf peach was significantly lower than those in Meirenmei and red-leaf prunus. Conclusion]The research provides certain theoretical basis for cultivation management of the 3 species and their better application in garden disposition.