Plant Diversity ›› 2024, Vol. 46 ›› Issue (03): 406-415.DOI: 10.1016/j.pld.2023.12.003

• Articles • Previous Articles    

Hydraulic properties and drought response of a tropical bamboo (Cephalostachyum pergracile)

Wanwalee Kongjarata,b, Lu Hana,b, Amy Ny Aina Aritsaraa,c, Shu-Bin Zhanga,c, Gao-Juan Zhaoa,c, Yong-Jiang Zhangd,e, Phisamai Maenpuena,b, Ying-Mei Lif, Yi-Ke Zoua,b, Ming-Yi Lia,g, Xue-Nan Lia,h, Lian-Bin Taoa, Ya-Jun Chena,c,i   

  1. a. CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Yunnan 666303, China;
    b. University of the Chinese Academy of Sciences, Beijing 100049, China;
    c. T-STAR Core Team, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Yunnan 666303, China;
    d. School of Biology and Ecology, University of Maine, Orono, ME, USA;
    e. Climate Change Institute, University of Maine, Orono, ME 04469, USA;
    f. School of Biological and Chemical Science, Pu'er University, Xueyuan Road, Yunnan 665000, China;
    g. Institute of Ecology and Geobotany, School of Ecology and Environmental Sciences, Yunnan University, Kunming, Yunnan 650091, China;
    h. School of Ecology and Environment, Southwest Forestry University, Kunming, Yunnan 650224, China;
    i. Yuanjiang Savanna Ecosystem Research Station, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Yuanjiang, Yunnan 653300, China
  • Received:2023-11-09 Revised:2023-12-20 Published:2024-05-20
  • Contact: Amy Ny Aina Aritsara,E-mail:amyaritsara@xtbg.ac.cn;Ya-Jun Chen,E-mail:chenyj@xtbg.org.cn
  • Supported by:
    The authors thank Peng-Yun Yang for his help during the measurements, Bin Yang and Xia Yuan in stable isotope analysis. We are also grateful for the support of the horticulture department of XTBG in sample collection and the National Forest Ecosystem Research Station at Xishuangbanna for providing the climatic data at the research site. This work was supported by the National Natural Science Foundation of China (Nos:32071735, 32371576, 32350410420, 41861144016, and 31570406); CAS ‘Light of West China' Program; The 14th Five-Year Plan of the Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences (E3ZKFF1K, E3ZKFF2B); Yunnan Provincial Science and Technology Department (2018HB068), and Yunnan Revitalization Talents Support Plan (YNWR-QNBJ-2019177).

Abstract: Bamboo plants are an essential component of tropical ecosystems, yet their vulnerability to climate extremes, such as drought, is poorly understood due to limited knowledge of their hydraulic properties. Cephalostachyum pergracile, a commonly used tropical bamboo species, exhibited a substantially higher mortality rate than other co-occurring bamboos during a severe drought event in 2019, but the underlying mechanisms remain unclear. This study investigated the leaf and stem hydraulic traits related to drought responses, including leaf-stem embolism resistance (P50leaf; P50stem) estimated using optical and X-ray microtomography methods, leaf pressure-volume and water-releasing curves. Additionally, we investigated the seasonal water potentials, native embolism level (PLC) and xylem water source using stable isotope. We found that C. pergracile exhibited strong resistance to embolism, showing low P50leaf., P50stem, and turgor loss point, despite its rapid leaf water loss. Interestingly, its leaves displayed greater resistance to embolism than its stem, suggesting a lack of effective hydraulic vulnerability segmentation (HVS) to protect the stem from excessive xylem tension. During the dry season, approximately 49% of the water was absorbed from the upper 20-cm-deep soil layer. Consequently, significant diurnal variation in leaf water potentials and an increase in midday PLC from 5.87±2.33% in the wet season to 12.87±4.09% in the dry season were observed. In summary, this study demonstrated that the rapid leaf water loss, high reliance on surface water, and a lack of effective HVS in C. pergracile accelerated water depletion and increased xylem embolism even in the typical dry season, which may explain its high mortality rate during extreme drought events in 2019.

Key words: Climate change, Drought, Hydraulic safety, Hydraulic vulnerability segmentation, Stable isotope, Tree mortality