Wang Qian, Gao Jianguo, Zhao Ping, Zhu Liwei, Ouyang Lei, Ni Guangyan, Zhao Xiuhua
Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, PR China.
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, PR China.
AoB Plants. 2018 Apr 20;10(3):ply025. doi: 10.1093/aobpla/ply025. eCollection 2018 Jun.
Although several studies on the night-time water use of different plant species have been reported, comparative studies under the same climatic conditions of a region are scarce. This study aimed to analyse the inter- and intraspecific variations in night-time water use in relation to environmental factors and to tree morphological features to understand and elucidate the possible underlying mechanisms. The sap flow of three co-occurring tree species in a low subtropical secondary broadleaf forest in South China was monitored using Granier-style sap flux sensors. All examined environmental factors except wind speed exerted significant influence on the daytime sap flows of , and , but the impacts of all factors, including wind speed, on the night-time sap flux were trivial. These results indicated that sap flow was mainly used for water recharge at night. The morphological features of the trees, except tree height, significantly affected the daytime water use, but no morphological features significantly affected the night-time water use. We found that night-time water recharge was strongly affected by the maximum flux density. A principal component analysis showed that there were more intraspecific than interspecific variations in water transport. The results also revealed that the night-time water use and the percentage of night/day (/) of photosynthetic stem species ( and ) were greater than those of non-photosynthetic stem species ().
尽管已有多项关于不同植物物种夜间水分利用的研究报道，但在同一地区相同气候条件下的比较研究却很少。本研究旨在分析夜间水分利用的种间和种内差异与环境因素及树木形态特征的关系，以理解和阐明可能的潜在机制。利用Granier型液流传感器监测了中国南方低亚热带次生阔叶林中共存的三种树木的液流。除风速外，所有检测到的环境因素均对樟树、荷木和藜蒴的白天液流产生显著影响，但包括风速在内的所有因素对夜间液流通量的影响都很小。这些结果表明，夜间液流主要用于水分补充。树木的形态特征，除树高外，对白天的水分利用有显著影响，但没有形态特征对夜间水分利用有显著影响。我们发现夜间水分补充受最大通量密度的强烈影响。主成分分析表明，水分运输中种内变异比种间变异更多。结果还表明，光合树干物种（樟树和荷木）的夜间水分利用和夜/日（N/D）百分比大于非光合树干物种（藜蒴）。
