Hydraulic traits are coupled with plant anatomical traits under drought-rewatering cycles in Ginkgo biloba L.
- 1College of Environmental Science and Engineering, Shaanxi University of Science & Technology (lishan.ecology@hotmail.com)
- 2Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing, P.R. China, 100091
- 3Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, P.R. China
Investigating the responses of plant anatomical traits of trees to drought-rewatering cycles helps us to understand their responses to climate change; however, such work has not been adequately reported. In this study, Ginkgo biloba L. saplings were subjected to moderate, severe, extreme and lethal drought conditions by withholding water according to PLCs (the percentage loss of hydraulic conductivity) and rewatering on a regular basis. Samples of phloem, cambium, and xylem were collected to quantify their cellular properties, including cambium and phloem cell vitality, xylem growth ring width, pit aspiration rates and pit membrane thickness, using light microscopy and transmission microscopy. The results showed that the mortality rate of G. biloba saplings reached 90% at approximately P88 (xylem water potential inducing 88% loss of hydraulic conductivity). The onset of cambium and phloem cell mortality might be in accordance with that of xylem embolism. Close negative correlations between xylem water potential and PLC and between xylem water potential and cambium and phloem mortality suggested that xylem hydraulic traits are coupled with anatomical traits under declining xylem water potential. Cambium and phloem cell vitality as well as xylem growth ring width decreased significantly with increasing drought conditions. However, xylem pit membrane thickness, cambial zone width and cambial cell geometry were not affected by the drought-rewatering cycles. The tracheid radial diameter, inter-tracheid cell wall thickness and tracheid density decreased significantly during both drought conditions and rewatering conditions. In addition to hydraulic traits, cambium and phloem cell vitality can be used as anatomical traits to evaluate the mortality of G. biloba under drought. Future work is proposed to observe the dynamics of pit aspiration rates under drought-rewatering cycles in situ to deepen our understanding of the essential role of bordered pits in the “air seeding” mechanism.
Key words: cambium and phloem cell vitality, xylem vulnerability curves, xylem growth ring width, pit membrane thickness, pit aspiration rate, tree mortality, lethal water potential under drought
https://academic.oup.com/treephys/advance-article-abstract/doi/10.1093/treephys/tpab174/6485193
How to cite: Li, S.: Hydraulic traits are coupled with plant anatomical traits under drought-rewatering cycles in Ginkgo biloba L., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1016, https://doi.org/10.5194/egusphere-egu22-1016, 2022.
