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神农架四种树生地衣对不同形态氮素胁迫的生理响应

郭华1,2,王传华1*,杨林1   

  1. (1三峡大学生物与制药学院, 湖北宜昌 443002; 2山西师范大学生命科学学院, 山西临汾 041000)
  • 出版日期:2016-03-10 发布日期:2016-03-10

Physiological response of four epyphytic lichens in Shennongjia Natural Reserve to different nitrogen stress.

GUO Hua1,2, WANG Chuan-hua1*, YANG Lin1   

  1. (1College of Life Science and Pharmacy, China Three Gorges University, Yichang 443000, Hubei, China; 2College of Life Sciences, Shanxi Normal University, Linfen 041000, Shanxi, China).
  • Online:2016-03-10 Published:2016-03-10

摘要: 为揭示氮沉降增加对神农架地区地衣多样性的潜在影响,本文以该地区常见的4种树生地衣\[肺衣(Lobaria pulmonaria)、东方肺衣(Lobaria orientalis)、小刺褐松萝(Usnea luridorufa)和粗毛松萝(Usnea dasopoga)\]为对象,以去离子水和不同浓度的硝态氮(KNO3 0.05、0.5 mol·L-1)、铵态氮((NH4)2SO4 0.025、0.25 mol·L-1)和混合氮(NH4NO3 0.05、0.5 mol·L-1)溶液浸泡处理地衣,测定氮处理的荧光诱导曲线参数、地衣浸出液电导率(RE)和叶绿素OD435/OD415值,分析4种地衣的氮敏感性以及硝态氮、铵态氮和混合氮对4种地衣光合色素稳定性、光系统Ⅱ及细胞膜稳定性的毒性差异性。结果表明:(1)不同形态氮素对地衣的毒性及其作用途径存在差异性。其中,混合氮对地衣光合系统的毒性尤其显著,对地衣Fv/Fm、Y(Ⅱ)和OD435/OD415的毒性总体呈现混合氮>铵态氮>硝态氮;不同氮素对地衣的细胞膜完整性毒性存在显著差异,呈现出铵态氮>混合氮>硝态氮;硝态氮单独作用对4种地衣的叶绿素稳定性、光系统Ⅱ及细胞膜稳定性毒性均较低;(2)4种地衣的氮敏感性表现出种特异性。硝态氮处理的OD435/OD415以粗毛松萝最为敏感,肺衣最不敏感;混合氮处理对Fv/Fm毒性表现为肺衣≈东方肺衣>小刺褐松萝≈粗毛松萝,对RE的影响表现为肺衣≈东方肺衣<小刺褐松萝≈粗毛松萝;铵态氮处理对Fv/Fm毒性表现为小刺褐松萝≈东方肺衣>粗毛松萝≈肺衣,对OD435/OD415的毒性表现为肺衣≈东方肺衣<小刺褐松萝≈粗毛松萝。上述研究结果可为我国氮沉降增加背景下神农架自然保护区地衣多样性的保护与管理提供理论依据。

关键词: 耐热性, 综合评价, 杜鹃花, 叶片解剖结构

Abstract: In order to explore the potential impact of increasing nitrogen deposition on lichen diversity in the Shennongjia Natural Reserve, four common epiphytic lichens (Lobaria pulmonaria, L. orientalis, Usnea luridorufa and U. dasopoga) in this area were collected, then they were soaked in deionized water and KNO3 (0.05, 0.5 mol·L-1), NH4NO3 (0.05, 0.5 mol·L-1), and (NH4)2SO4 (0.025, 0.25 mol·L-1) solutions for half an hour. The fluorescence induction curve parameter, solution electrical conductivity (RE, namely cell membrane integrity) and chlorophyll degradation (OD435/OD415) were measured. The sensibilities of the four lichens to nitrogen additions and the stress of ammonium nitrogen, nitrate nitrogen and mixed nitrogen on Fv/Fm, RE and OD435/OD415 were analyzed. The results showed that: (1) There were significant differences among the responses of lichens to different nitrogen forms. The toxicity of different nitrogen forms to Fv/Fm, Y(Ⅱ) and OD435/OD415 were in the order of mixed nitrogen > ammonium nitrogen > nitrate nitrogen, and their toxicity to cell membrane integrity presented as ammonium nitrogen > mixed nitrogen > nitrate nitrogen, while nitrate nitrogen alone had little toxicity to Fv/Fm, Y(Ⅱ), OD435/OD415 of these four lichens. (2) Nitrogen sensitivities of these four lichens were speciesspecific. When treated with nitrate nitrogen, OD435/OD415 of U. dasopoga appeared more sensitive than that of L. pulmonaria. If mixed nitrogen was used, the toxicity to Fv/Fm was in the order of L. pulmonaria≈L. orientalis>U. luridorufa≈U. dasopoga, while the toxicity to RE was L. pulmonaria≈L. orientalis<U. luridorufa≈U. dasopoga. When they were treated with ammonium nitrogen, the toxicity to Fv/Fm was in the order of U. luridorufa≈L. orientalis>U. dasopoga≈L. pulmonaria, and the toxicity to OD435/OD415 presented as L. pulmonaria≈L. orientalis<U. luridorufa≈U. dasopoga. Under an increasing nitrogen deposition background, our result is of special importance in lichen diversity protection and management in Shennongjia Nature Reserve.

Key words: leaf anatomical structure, heat resistance, Rhododendron, comprehensive evaluation