深山含笑等18个景观树种光合生理特性研究

Study on Photosynthetic Physiological Characteristics of 18 Kinds of Landscape Trees Including Michelia maudiae

以深山含笑(Michelia maudiae)等18个景观树种为研究材料,采用Li-6400光合作用测定系统测定光合、蒸腾、水分利用效率等生理参数及其光响应过程,探讨景观树种在自然生境下的光合生理特征。结果表明:18个景观树种光响应曲线符合非直角双曲线模型(R2>0.99),最大净光合速率为8.15～22.02μmol.m-2.s-1,表观量子效率为0.045～0.234,光饱和点为878.7～1 949.3μmol.m-2.s-1,光补偿点为1.3～18.7μmol.m-2.s-1,18个景观树种光适应性介于典型阴生植物和阳生植物之间。红花羊蹄甲(Bauhinia blakeana)、红花荷(Rhodoleia championii)、木棉(Bombax ceiba)、紫薇(Lagerstroemia indica)和穗花棋盘脚(Barringtonia racemosa)具有较高的净光合速率和水分利用效率。水分利用效率以火焰木最大,大花紫薇最小,与蒸腾速率恰好相反,而净光合速率并未表现出一致性,表明该地区景观树种的水分利用效率受蒸腾速率的影响可能更大。

By using Li-6400 portable photosynthesis system, we measured 18 landscaping trees including Michelia maudiae for comparative studies on photosynthetic and physiological parameter characteristics, such as photosynthesis, transpiration, and water use efficiency etc. , and photosynthesis and photo-response characteristic of Michelia maudiae and others in natural habitats in Guangzhou, South China. The results showed that the photo- synthesis-light response curves of the 18 species could be well simulated by the non-rectangular hyperbola model （R2 〉 0.99）. The maximum net photosynthetic rate was between 8.15 -22.02 μmol · m^-2 ·s^-1, apparent quan- tum yield was between 0. 045 ~ 0. 234, light saturation point was between 878.7 ~ 1 949.3 μmol · m^-2 ·s^-1, light compensation point was between 1.3 - 18.7 μmol · m^-2 ·s^-1 These tree species fell in between tropical shade plants and sun plants in photosynthetic characteristics. Bauhinia blakeana, Rhodoleia championii, Bombax ceiba, Lagerstroemia indica and Barringtonia racemosa had higher net photosynthetic rate and water use efficiency than the others. Among all 18 species, water use efficiency （WUE） was highest for Spathodea campanulata andlowest for Lagerstroemia speciosa, while transpiration rate was the opposite, suggesting that WUE of landscape trees in this region was influenced by transpiration rate.