不同原生境的6种棕榈科植物叶片水力性状的对比研究

为揭示生长在湿润生境和季节性干旱生境棕榈科植物的水分生理生态适应的差异,在中国科学院华南植物园中选取3种原分布于湿润生境(SOMH)植物:澳洲轴榈(Licualaramsayi)、槟榔(Arecacatechu)和所罗门皱籽棕(Ptychosperma salomonense),以及3种原分布于季节性干旱生境(SODH)植物:大丝葵(Washingtonia robusta)、澳洲蒲葵(Livistona australis)和大蒲葵(L. saribus),对叶片和叶柄的结构与功能性状进行测定。结果表明,与SODH物种相比,3种SOMH植物的水力加权导管直径(Dh)、理论导水率(Kth)、膨压丧失点(TLP)、脆弱性指数(VI)和比叶面积(SLA)较高,而其叶脉密度(VD)较低。TLP、VI均与Kth呈显著正相关,说明水力效率和水力安全之间存在权衡关系。可见,SOMH棕榈的叶片水力效率高于SODH棕榈,但叶片水力安全低于SODH,这揭示了生长于不同生境棕榈科植物在水分生理生态策略上的差异。

Comparative Studies on Leaf Hydraulic Traits of Six Palm (Arecaceae) Species Originally Distributed in Different Habitats

In order to reveal the difference of water ecophysiological adaptation of plants in humid and seasonal arid habitats, the structure and functional traits of leaves and petioles of six palm species in South China Botanical Garden, Chinese Academy of Sciences were studied, including three species originally distributed in moist habitats (SOMH): Licuala ramsayi, Areca catechu and Ptychosperma salomonense, and three species in seasonally dry habitats (SODH): Washingtonia robusta, Livistona australis and L. saribus. The results showed that hydraulically weighted vessel diameter (D_h), theoretical hydraulic conductivity (K_th), leaf turgor loss point (TLP) vulnerability index (VI) and specific leaf area (SLA) of SOMH were significantly greater than those of SODH, whereas SODH had the significantly greater vein density (VD) than SOMH. Meanwhile, the VI and TLP had positive correlation with K_th, indicating that there was a trade-off between the hydraulic efficiency and safety for these palm species. In conclusion, the leaf hydraulic efficiency of SOMH was higher than that of SODH, but the leaf hydraulic safety was lower than that of SODH. It was revealed that the differences in water ecophysiological strategies of palm plants in different habitats.