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| Physiological responses to different soil water contents in Xanthoceras sorbifolia Bunge. , Diospyros kaki Linn. and Zanthoxylum bungeanum Maxim. Seedlings |
| Ai Zhao1, Chen Zhicheng2, Yang Fei1, Li Sai1, Wang Zhiwei1, Zhang Yongtao1 |
1. Forestry College of Shandong Agricultural University, 271018, Tai'an, Shandong, China;
2. Institute of New Forestry Technology, Chinese Academy of Forestry, 100091, Beijing, China |
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Abstract Water deficit is one of the major factors limiting plants grown on the hills in Shandong Province. Xanthoceras sorbifolia Bunge. , Diospyros kaki Linn. and Zanthoxylum bungeanum Maxim. are common afforestation tree species in Shandong. The mechanisms of the physiological change of these tree species in different drought regimes and their drought resistance remain unclear. Through pot and field experiments, we evaluated the drought-resistant ability of the above three tree species by investigating the process and mechanism of their physiological changes in response to drought stress. The physiological responses of two-year-old X. sorbifolia, D. kaki and Z. bungeanum seedlings to soil drought stress were examined by natural drought method in pot experiments. The results showed that: 1) With the relative soil water content (Wr) reducing, the relative leaf water content and the chlorophyll content decreased gradually, the proline content and relative permeability of cell membrane increased, net photosynthetic rate (Pn), water use efficiency and superoxide dismutase activity increased initially and then decreased, malondialdehyde content increased firstly and then decreased and ascended again; 2) When the soil water content was 60% -70%, 30% -40% and 20% -30%, the stomatal limitation of Pn changed into non-stomatal limitation in X. sorbifolia, D. kaki and Z. bungeanum seedlings, respectively. In general, drought-resistant capability of Z. bungeanum is the strongest under moderate water stress, D. kaki is thebest under severe water stress, and X. sorbifolia is the poorest under all experimental conditions. Combining the field growth performance, it is suggested that Z. bungeanum be an optimum species for afforestation in hilly regions of Shandong Province.
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Received: 20 November 2013
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