Chin J Plant Ecol ›› 2020, Vol. 44 ›› Issue (3): 192-204.DOI: 10.17521/cjpe.2019.0304

• Research Articles • Previous Articles     Next Articles

Hydraulic and photosynthetic characteristics differ between co-generic tree and liana species: a case study of Millettia and Gnetum in tropical forest

SONG Hui-Qing,NI Ming-Yuan,ZHU Shi-Dan()   

  1. Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, China; and State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning 530004, China
  • Received:2019-11-07 Accepted:2020-02-01 Online:2020-03-20 Published:2020-03-26
  • Contact: Shi-Dan ZHU ORCID:0000-0002-9228-368X
  • Supported by:
    National Natural Science Foundation of China(31470468)


Aims Liana is an important component of tropical forest, and exert a significant impact on community structure and function. Previous studies have found significant differences in hydraulic traits between lianas and trees, as indicated that lianas tended to have large and long vessels to compensate hydraulically to their thin stems, resulting in high hydraulic conductivity but low resistant to drought-induced cavitation. In order to reduce the influence of different genotypes on the comparative results, we aimed to compare the differences in hydraulic and photosynthetic characteristics between the two life forms from two genera Millettia and Gnetum.
Methods We measured branch and leaf hydraulic properties, sapwood density, gas exchange rates in the dry season for nine tree and liana species grown in common garden. We compared the hydraulic and photosynthetic traits between each species using one-way ANOVA. In addition, we analyzed hydraulic efficiency-safety trade-off, and the relationship between dry-season photosynthetic rates and hydraulic traits.
Important findings (1) There was a significant variations in hydraulic traits in genus Millettia, which was related to their light requirements and life forms. Compared with trees, the shade-tolerant liana species had lower hydraulic conductivity and higher resistance to cavitation. (2) Despite angiosperm-like characteristics such as vessels and broad pinnate-veined leaves, the Gnetum tree species had the lowest hydraulic conductivity among the nine species. However, the Gnetum liana species had higher hydraulic conductivity, comparable to light-demanding angiosperm species in this study. (3) There was no significant trade-off between hydraulic conductivity efficiency and hydraulic safety in both branch- and leaf-level across all the species, or within each plant group. (4) Compared to co-generic tree species, liana species’ leaves were more resistant to cavitation than branches, as indicated by higher maximum net photosynthetic rates and stomatal conductance during the dry season. These results support the hypothesis of “growth advantages at dry season” for liana species. This study reveals the high diversity and significance of hydraulic functioning in tropical lianas. Extensive measurements of hydraulic properties are needed to promote understanding of tropical species response to environmental change.

Key words: hydraulic function, cavitation resistance, trade-off, vulnerability segmentation, photosynthetic rates