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| 三峡库区岸生植物秋华柳对镉胁迫的光合响应 | |
| 引用本文： | 贾中民,程华,魏虹,李昌晓.三峡库区岸生植物秋华柳对镉胁迫的光合响应[J].林业科学,2012,48(6):152-158. |
| 作者姓名： | 贾中民 程华 魏虹 李昌晓 |
| 作者单位： | 1. 三峡库区生态环境教育部重点实验室西南大学生命科学学院 重庆400715;重庆市地质矿产勘查开发局川东南地质大队 重庆400038 2. 安阳工学院 安阳 455000 3. 三峡库区生态环境教育部重点实验室西南大学生命科学学院 重庆400715 |
| 基金项目： | 国家林业公益性行业科研专项，国家教育部“留学回国人员科研启动金”，重庆市自然科学基金，中央高校基本科研业务费专项资金重点项目，西南大学发展基金资助项目 |
| 摘 要： | 镉是一种植物非必需元素,以毒性强、在土壤-植物系统中移动性大等特点受到广泛关注,它在生物圈中通常给生物带来有害的生态效应。土壤中过量的镉会引起植物的许多胁迫症状,研究表明:叶镉浓度超过5～10mg·kg-1(干质量)时对大多数植物都是有害的(Whiteetal.,2010);镉能抑制叶绿素的生物合成并导致叶绿素含量的下降和不同色素 |
| 关 键 词： | 秋华柳 镉 气体交换参数 叶绿素荧光 |
Photosynthetic Responses of the Riparian Salix variegata to Cadmium Stress in Three Gorges Reservoir Region |
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| Jia Zhongmin , Cheng Hua , Wei Hong , Li Changxiao.Photosynthetic Responses of the Riparian Salix variegata to Cadmium Stress in Three Gorges Reservoir Region[J].Scientia Silvae Sinicae,2012,48(6):152-158. | |
| Authors: | Jia Zhongmin Cheng Hua Wei Hong Li Changxiao |
| Institution: | 1(1.Key Laboratory of Eco-Environments of the Three Gorges Reservoir Region of Ministry of Education College of Life Science,Southwest University Chongqing 400715;2.Southeast Sichuan Geological Group,Chongqing Bureau of Geology and Minerals Exploration Chongqing 400038;3.Anyang Institute of Technology Anyang 455000) |
| Abstract: | High cadmium concentration and its bioavailability in the sediment of Three Gorges Reservoir Region have a negative effect on the soil-plant ecosystem in the hydro-fluctuation zone of the region.Salix variegate,a native riparian plant species,can be used widely in vegetation restoration of the hydro-fluctuation zone in this region.Although some plants have evolved mechanisms to limit Cd translocation to the shoot thereby avoiding cadmium toxicity,leaf Cd concentrations in excess of 5-10 mg·kg-1 dry matter are toxic to most plants.In order to reveal the photosynthetic adaptive mechanism of S.variegata to cadmium contaminated soils,the photosynthetic chlorophyll contents,gas exchange parameters and chlorophyll fluorescence characteristics of S.variegata seedlings were measured under treatments with five different concentrations of heavy metal Cd2 +.The cadmium treatments were 0(CK),10,20,50,100 mg·kg-1.The results showed that:1) Chl a,Chl b,Total Chls and carotenoid contents of treated S.variegata seedlings were significantly lower than that in controlled plants except for in 10 mg·kg-1,while Chl a /b ratio in above 50 mg·kg-1 Cd2 + treated seedlings was significantly lower than controlled plants(P < 0.05),indicating that the inhibitory effect of cadmium on Chl a was more severe than on Chl b,especially above 50 mg·kg-1.2) The net photosynthetic rate(Pn),stomatal conductance(Gs) and transpiration rate(Tr) of S.variegata seedlings treated with cadmium significantly decreased compared to the control(P < 0.05).Meanwhile,intercellular CO2 concentration(Ci) of S.variegata seedlings increased gradually and stomatal limitation(Ls) decreased.These results suggested that the predominant reason for decline of Pn of S.variegata was non-stomatal factors.Cadmium would induce closure of stomata and result in reduction in Gs,but was not the direct or solely reason for the reduced net photosynthetic rate.S.variegata seedlings had a high photosynthetic adaptation to cadmium because the net photosynthetic rate in plants exposed to 10 mg·kg-1 cadmium still was 84.9% of the control level.3) Changes in photosynthesis of S.variegata affected by cadmium stress were also determined using chlorophyll fluorescence parameters.The decrease of Fv /Fm and qP in 10-20 mg·kg-1 treatments were not significantly different from the control,indicating that the photoinhibition and the decreased degree of PS II reaction center were slight.The ratio of F’v /F’m,ΦPS Ⅱ and ETR were significantly inhibited by cadmium,especially above 50 mg·kg-1,demonstrating a severe fall in efficiency of the photochemical reduction of QA,and the reaction center capturing excitation energy.NPQ increased with increasing cadmium concentration,which might be responsible for tolerance of S.variegata seedlings to heavy metal cadmium due to form protecting mechanism through elevating its abilityof dissipating heat.This research revealed that S.variegata seedlings had relatively high tolerance to cadmium,and would be a promising species for phytoremediation of those cadmium contaminated areas in the hydro-fluctuation zone of the Three Gorges Reservoir Region. |
| Keywords: | Salix variegata cadmium gas exchange parameters chlorophyll fluorescence |
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