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

Abstract:

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.

Key words:Palm (Arecaceae);Hydraulic efficiency;Hydraulic safety;Trade-off