Journal of Ecology and Rural Environment ›› 2018, Vol. 34 ›› Issue (3): 224-231.doi: 10.11934/j.issn.1673-4831.2018.03.005

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Effects of Flooding Stress on Growth and Photosynthetic Physiological Traits of Phoebe zhennan Saplings

CHEN Yu-feng1, TAN Fei1,2, HU Hong-ling1, HU Ting-xing1, YU Xiu-yan1, ZHOU Xin1, YANG Shan-shan1, ZHANG Cheng-hao1, ZHANG Jian1   

  1. 1. College of Forestry, Sichuan Agricultural University, Chengdu 611130, China;
    2. Liangshan Forestry Survey and Planning Institute, Xichang 615000, China
  • Received:2017-05-26 Online:2018-03-25 Published:2018-03-23

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Abstract:

To study effects of flooding on growth and photosynthetic physiology of Phoebe zhennan saplings and provide certain theoretical basis for cultivation and water management of P. zhennan saplings, a pot experiment was conducted with the pots planted with 2.5 year-old P. zhennan saplings and flooded. The experiment was designed to have 6 groups or treatments, 5 saplings each, for duration of flooding, i.e. 0(CK), 7, 14, 21, 28 and 35 days. Growth and photosynthetic indexes of the P. zhennan saplings in all the treatments were monitored. Results show:(1) Flooding significantly inhibited growth of the plants, though basal diameter of the plants increased first and then decreased in all the treatments. Net plant height decreased by 43.4%, 59.2%, 59.2% and 80.8% in Treatment 7D, 14D, 21D and 28D, respectively, as compared with CK(0 d), and the plants in Treatment 35D failed to survive; (2) Flooding altered the content and ratio of chloroplast pigments of P zhennan saplings in all the treatments, the contents of chlorophyll a (Chl a) decreased by 17.4%, 22.0%, 38.4% and 52.3%, respectively, while carotenoids/chlorophyll ratio increased by 32.3%, 71.0%, 32.3% and 45.2%, respectively in Treatment 7D, 14D, 21D and 28D, showing a trend of rising first and then declining; (3) Net photosynthetic rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) were declining significantly with the stress going on and, decreased by 89.6%, 98.2% and 98.7%, respectively in Treatment 28D. However, the concentration of carbon dioxide (Ci) between cells significantly increased by 216.2% in Treatment 28D; And (4) in the plants under stress, light compensation point (Lcp) and CO2 compensation point (Ccp) showed an increasing trend, while the max net photosynthetic rate (Pn,max) and light saturation point (Lsp) decreased dramaticly. In conclusion, P. zhennan saplings exhibited showed low resistance to flooding stress, which significantly inhibited air exchange and photosynthetic rate and weakened the plants' ability to make use of light and CO2, and hence their photosynthetic capacity. In the experiment, the saplings exhibited their physio-ecological traits of low resistance to flooding. Most of the saplings began to wilt and die after 28 days of flooding and all the saplings died after 35 days of flooding.

Key words: submergence stress, Phoebe zhennan sapling, chlorophyll, photosynthetic physiology, growth

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