常绿园林植物香樟叶内生物量分配与含水量特征及其相互关系

Biomass Allocation, Water Content and Their Interrelations within Leaves of Cinnamomum camphora,an Evergreen Garden Plant

【目的】以安庆市区常绿园林绿化植物香樟为研究对象,探讨香樟叶片、叶柄生物量分配及含水量在生长季(发育阶段)和树冠方位上的差异格局及相互关系。【方法】在夏季和冬季分别采集树冠南北两侧叶片样品,测定叶内生物量与含水量。【结果】生长季对叶生物量和含水量指标影响显著(P<0.05),而树冠方位仅对叶含水量有一定影响。冬季香樟叶片生物量分配比例低于夏季,而叶柄分配比例则相反。香樟叶内含水量表现为夏季高于冬季、叶柄高于叶片的特征。夏季叶片和叶柄生物量之间表现为等速生长关系,而冬季柄分配比例大于叶片的异速生长关系。不同生长季香樟叶柄生物量分配与其含水量之间为极显著负相关(P<0.01),表明高的叶柄含水量不利于支撑构件投资;叶柄生物量分配与叶片大小呈U型关系,表明中等大小的叶具有最小化的支撑投资。【结论】香樟在不同生长季具有变化的叶内生物量分配策略,但叶内生物量分配与含水量和叶片大小的关系则相对稳定。

[Purpose]To analyze the variation patterns of lamina-petiole biomass allocation and water contents and their covariation characteristics of an evergreen garden plant Cinnamomum camphora in relation to growing season(i.e, developmental stage), canopy orientation in Anqing City.[Method]A total of 840 leaves at both north and south canopies were collected in summer and winter respectively, and then the biomass and water content within leaves were determined.[Result]Growing season significantly influenced leaf biomass and water content parameters of C. camphora, while canopy orientation just affected water contents(P< 0.05). The lamina biomass allocation ratio of C. camphora in winter was lower than that in summer, while the petiole allocation ratio presented the opposite tendency. The water contents within leaf indicated higher values in summer than that in winter, and higher values in petiole than that in lamina. Lamina and petiole biomass represented an isometric relationship in summer, while in winter they presented an allometric relationship showing petiole allocation ratio was higher than lamina. Biomass allocations of petiole and its water contents of C. camphora showed obvious negative correlations in both two growing seasons(P<0.01), indicating that higher petiole water content lower support investment. Petiole biomass allocations showed U-shaped relationships with leaf biomass, indicating that medium leaf size has minimum support investment.[Conclusion]C. camphora presented varied biomass allocation strategy within leaf in different growing seasons, but the relationships between biomass allocation within leaf, water content and leaf size showed relatively stable.