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Scientia Silvae Sinicae ›› 2019, Vol. 55 ›› Issue (7): 17-26.doi: 10.11707/j.1001-7488.20190702

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Growth, Survival and Physiological Response of Food Lichens Usnea longissima of Rhinopithecus roxellana to Simulated Nitrogen Deposition

Jia Raozhen1, Wang Ming1,2, Wang Chuanhua1,2,3   

  1. 1. Hubei International Scientific and Technological Cooperation Center of Ecological Protection and Management in the Three Gorges Area Yichang 443002;
    2. China Engineering Research Center of Eco-Environment in the Three Gorges Reservoir Region, Ministry of Education Yichang 443002;
    3. College of Life Science and Pharmacy, China Three Gorges University Yichang 443002
  • Received:2018-01-04 Revised:2019-05-31 Online:2019-07-25 Published:2019-08-16

Abstract: [Objective] We aimed to investigate the response of growth and survival, and potential physiological mechanisms of Usnea longissima of Shennongjia Mountain to simulated nitrogen deposition. Our result were of value in winter food management of Rhinopithecus roxellana, as well in understanding the succession of lichen flora under condition of increasing nitrogen deposition of that region.[Method] In this study, four in-situ or indoor experiments were performed, in which simulated nitrogen deposition were imposed on thalli and propagules of U. longissima. Thereafter, thalli growth rate and propagule survival rate, adsorption of ammonium and nitrate, thalli N:P ratio and activity of phosphomonoesterase (PME), glutamine synthetase (GS), and nitrate reductase (NR) were determined. Then we analyzed the growth, survival response of U. longissima and its potential mechanisms to simulated nitrogen deposition.[Result] The result showed that thalli growth and propagule survival were significantly impacted when high nitrogen deposition (>32.99 kgN·hm-2a-1) were performed; In contrast, low nitrogen deposition (<20.94 kgN·hm-2a-1) promoted growth of this lichen. We also found that little nitrate was absorbed, while ammonium was absorbed efficiently. Total nitrogen, N:P ratio, activity of PME increased with increased N deposition, indicating that phosphorous limitation occurred when U. longissima treated with higher nitrogen deposition. Activity of GS and NR both responded nitrogen stress in a first up-regulated, and then down-regulated way.[Conclusion] Low N deposition showed a fertilization effect on the growth of U. longissima, high nitrogen deposition could decrease thalli growth and survival of its propagules. The possible mechanisms underlying it was:U. longissima preferred to uptake and accumulate ammonium, meanwhile high nitrogen stress reduced activity of GS and NR significantly. In addition, high nitrogen stress would induce a phosphorus limitation.

Key words: Shennongjia Nature Reserve, Usnea longissima, nitrogen deposition, growth and survival

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