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

• Published in: Plant diversity Vol. 46; no. 3; pp. 406 - 415
• Main Authors: Kongjarat, Wanwalee, Han, Lu, Aritsara, Amy Ny Aina, Zhang, Shu-Bin, Zhao, Gao-Juan, Zhang, Yong-Jiang, Maenpuen, Phisamai, Li, Ying-Mei, Zou, Yi-Ke, Li, Ming-Yi, Li, Xue-Nan, Tao, Lian-Bin, Chen, Ya-Jun
• Format: Journal Article
• Language: English
• Published: China KeAi Communications Co., Ltd 01.05.2024
• Subjects: bamboos; Cephalostachyum; climate; Climate change; diurnal variation; Drought; dry season; embolism; Hydraulic safety; Hydraulic vulnerability segmentation; leaves; micro-computed tomography; mortality; soil; species; species diversity; Stable isotope; stable isotopes; surface water; Tree mortality; turgor; wet season; xylem; xylem tension; Tree mortality; Climate change; Stable isotope; Hydraulic vulnerability segmentation; Drought; Hydraulic safety
• DOI: 10.1016/j.pld.2023.12.003
• ISSN: 2468-2659

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. , 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 (P ; P ) 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 . exhibited strong resistance to embolism, showing low P , P , 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 . 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.