神农架四种树生地衣对不同形态氮素胁迫的生理响应  

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

作　　者：郭华[1,2] 王传华[1] 杨林[1] 

机构地区：[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　　处：《生态学杂志》2016年第3期605-611,共7页Chinese Journal of Ecology

基　　金：国家自然科学基金项目(31370536)资助

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(KNO30.05、0.5 mol·L^(-1))、铵态氮((NH_4)_2SO_40.025、0.25 mol·L^(-1))和混合氮(NH_4NO_30.05、0.5mol·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。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 KNO_3（ 0.05,0.5 mol·L-1）,NH_4NO_3（ 0.05,0.5 mol·L^（-1））,and（ NH_4）_2SO_4（ 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/ Fmwas 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/ Fmwas 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 res

关 键 词：树生地衣 氮沉降 神农架自然保护区 

分 类 号：Q945.78[生物学—植物学]