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Scientia Silvae Sinicae ›› 2013, Vol. 49 ›› Issue (12): 164-170.doi: 10.11707/j.1001-7488.20131223

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Effects of Submergence-Drought Stresses on Growth and Physiological Characteristics of Salix rosthornii Seedlings

Wang Chaoying, Li Changxiao, Zhang Ye   

  1. College of Life Sciences, Southwest University Key Laboratory for the Eco-Environment of Three Gorges Reservoir Region of Ministry of Education Chongqing Key Laboratory of Plant Ecology and Resources Research in the Three Gorges Reservoir Region Chongqing 400715
  • Received:2012-11-06 Revised:2013-05-22 Online:2013-12-25 Published:2014-01-01

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Abstract:

To explore the effects of water level change in the Three Gorges Reservoir (TGR) on the growth and physiological traits of two-year-old Salix rosthornii seedlings, treatments of four different water levels simulating the natural water level dynamic changes were applied to the seedlings, including control without any flooding (CK), water change with root submergence (T1), water change with half plant submergence (T2), and water change with whole plant submergence (T3). The seedlings in T1, T2 and T3 were all subject to water level change, at the very beginning to normal water supply, and then to light drought stress, and finally normal water supply again. The physiological adaptive mechanisms of these seedlings were studied. Results showed that different treatments significantly affected the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), and the content of malondialdehyde (MDA), proline, soluble protein, as well as the plant biomasses. In 65 days under the flooding treatments, the activities of SOD and CAT and the contents of MDA and proline in T1, T2 and T3 all increased. In contrast, the POD activity and soluble protein content in those treatments were firstly decreased and then increased. In addition, the submergence stress also led to a significant decline in the leaf biomass of the seedlings. After then the flood was trained to normal water supply and the seedlings were maintained in the water regimes until the 155th day, all the physiological indexes of the seedlings except for proline content were recovered to that of the control group. However, although plant biomass increased during the period, the leaf biomass and total biomass in T2 and T3 were still significantly lower than those in CK. Hereafter the seedlings were subject to light drought treatment until the 176th day, the SOD, POD and CAT activities in the plants increased, and the contents of MDA, proline and soluble protein were significantly higher than those of CK respectively, while seedlings still had significantly less leaf biomass and total biomass compared to control group. From the 176th day to 197th day when the seedlings were given with normal water supply, all the physiological indexes except for CAT were recovered to the levels of the control, and the plant biomass increased. However, the leaf and total biomass was still significantly smaller than CK. This study confirmed that S. rosthornii seedlings could be tolerant to water level change in the hydro-fluctuation belt of the TGR through regulating the activities of internal protective enzyme and the contents of osmotic regulators. However, the continuously negative effects of drought stress on S. rosthornii seedlings were stronger than those of flooding. Therefore, the water management in the S. rosthornii habitats should be strengthened, especially under drought situations.

Key words: water stress, Salix rosthornii seedlings, protective enzyme, membrane lipid peroxidation, growth traits, Three Gorges Reservoir

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