Plant Diversity ›› 2024, Vol. 46 ›› Issue (03): 395-405.DOI: 10.1016/j.pld.2024.02.003

• Articles • Previous Articles    

Stomatal dynamics are regulated by leaf hydraulic traits and guard cell anatomy in nine true mangrove species

Ya-Dong Qiea,b, Qi-Wei Zhangc,d, Scott A. M. McAdame, Kun-Fang Caoa,b   

  1. a. State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Nanning 530004, China;
    b. Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, China;
    c. Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, Ministry of Education, Guangxi Normal University, Guilin 541001, China;
    d. Guangxi Key Laboratory of Landscape Resources Conservation and Sustainable Utilization in Lijiang River Basin, Guangxi Normal University, Guilin 541001, China;
    e. Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
  • Received:2023-10-13 Revised:2024-01-04 Published:2024-05-20
  • Contact: Kun-Fang Cao,E-mail:kunfangcao@gxu.edu.cn
  • Supported by:
    We acknowledge the collaboration of the Dongzhaigang National Nature Reserve and Qinglan Harbor Provincial Mangrove Nature Reserve, and the Forestry Department of the Hainan Province for permission to conduct the field experiment in the mangrove reserves. The authors thank Prof. Jun-Jie Zhu for the experimental design, Yang Wei for field assistance, Jin-Yan Lei and Pei-Xin Cui for their help in leaf anatomy. This study was financially supported by a grant of the National Natural Science Foundation of China (31670406) and the Bagui Fellow scholarship (C33600992001) of Guangxi Zhuang Autonomous Region to KFC.

Abstract: Stomatal regulation is critical for mangroves to survive in the hyper-saline intertidal zone where water stress is severe and water availability is highly fluctuant. However, very little is known about the stomatal sensitivity to vapour pressure deficit (VPD) in mangroves, and its co-ordination with stomatal morphology and leaf hydraulic traits. We measured the stomatal response to a step increase in VPD in situ, stomatal anatomy, leaf hydraulic vulnerability and pressure-volume traits in nine true mangrove species of five families and collected the data of genome size. We aimed to answer two questions:(1) Does stomatal morphology influence stomatal dynamics in response to a high VPD in mangroves? with a consideration of possible influence of genome size on stomatal morphology; and (2) do leaf hydraulic traits influence stomatal sensitivity to VPD in mangroves? We found that the stomata of mangrove plants were highly sensitive to a step rise in VPD and the stomatal responses were directly affected by stomatal anatomy and hydraulic traits. Smaller, denser stomata was correlated with faster stomatal closure at high VPD across the species of Rhizophoraceae, and stomata size negatively and vein density positively correlated with genome size. Less negative leaf osmotic pressure at the full turgor (πo) was related to higher operating steady-state stomatal conductance (gs); and a higher leaf capacitance (Cleaf) and more embolism resistant leaf xylem were associated with slower stomatal responses to an increase in VPD. In addition, stomatal responsiveness to VPD was indirectly affected by leaf morphological traits, which were affected by site salinity and consequently leaf water status. Our results demonstrate that mangroves display a unique relationship between genome size, stomatal size and vein packing, and that stomatal responsiveness to VPD is regulated by leaf hydraulic traits and stomatal morphology. Our work provides a quantitative framework to better understand of stomatal regulation in mangroves in an environment with high salinity and dynamic water availability.

Key words: Stomatal temporal kinetics, Vapour-pressure deficit (VPD), Leaf water relations, Leaf hydraulic vulnerability, Leaf osmotic potential, Genome size