Eco-physiological mechanisms of Caragana korshinskii Kom.
adaptation to extreme drought stress: Leaf abscission and
maintaining stem chloroplast integrity |
| |
| Authors: | DangHui Xu XiangWen Fang ZhenJun Bin Gang Wang and PeiXi Su |
| |
| Institution: | 1. State Key Laboratory of Grassland Agro-ecosystems/School of Life Science, Lanzhou University, Lanzhou, Gansu 730000,
China
2. Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, Gansu
730000, China;State Key Laboratory of Grassland Agro-ecosystems/School of Life Science, Lanzhou University, Lanzhou, Gansu 730000,
China;State Key Laboratory of Grassland Agro-ecosystems/School of Life Science, Lanzhou University, Lanzhou, Gansu 730000,
China;State Key Laboratory of Grassland Agro-ecosystems/School of Life Science, Lanzhou University, Lanzhou, Gansu 730000,
China;Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, Gansu
730000, China |
| |
| Abstract: | In order to study the eco-physiological mechanisms of C. korshinskii adaptation to extreme drought stress, we investigated the
variations of water content in soil, leaves, and stems, the chlorophyll a and b and the carotenoid content in leaves and stems, as
well as changes of chloroplast ultrastructure in 2-year-old C. korshinskii specimens during a progressive soil drought process (by
ceasing watering until all leaves were shed) and a subsequent rehydration process. During the dehydration process, the chlorophyll
a and b and carotenoid contents in the leaves decreased, as did the carotenoid content in the stems. During the 4-day rehydration
process, the chlorophyll a and b and carotenoid contents in the leaves and stems increased and gradually returned to normal levels.
During ongoing drought stress, chloroplasts in the leaves broke away from cell walls and appeared in the center of cells. Under
severe drought stress, the mesophyll ultrastructure and chloroplast configuration in leaves were irreversibly disturbed, as manifested
by the inner and outer membranes being destroyed; the thylakoid system disintegrated, the starch grain disappeared, and
parts of cell tissue were dismantled into debris. However, the mesophyll ultrastructure and chloroplast configuration in the stems
remained complete. This indicates that C. korshinskii utilizes leaf abscission to reduce the surface area to avoid damage from extreme
drought stress, and maintains chloroplast integrity and a considerable amount of chlorophyll to enable a rapid recovery of
photosynthesis under the rehydration process. |
| |
| Keywords: | Caragana korshinskii extreme drought stress leaf abscission chloroplast ultrastructure |
|
| 点击此处可从《寒旱区科学》浏览原始摘要信息 |
| 点击此处可从《寒旱区科学》下载免费的PDF全文 |
|
