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| Effects of cadmium stress on growth and photosynthetic parameters of Sigesbeckia orientalis L. |
| Received:April 22, 2016 |
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| KeyWord:Sigesbeckia orientalis L.;cadmium stress;chlorophyll contents;gas exchange parameters;chlorophyll fluorescence parameters |
| Author Name | Affiliation | E-mail | | XU Xiao-xun | College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China | | | DONG Yuan-yuan | College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China | | | DENG Yu-lan | College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China | | | HUO Qing-lin | College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China | | | ZHANG Shi-rong | College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China | rsz01@163.com | | PU Yu-lin | College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China | |
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| Abstract: |
| The aim of this study is to examine the change of growth and photosynthetic parameters of Sigesbeckia orientalis L. under cadmium(Cd) stress through a soil pot experiment, and to analyze their roles in Cd tolerance. The results showed that the root length, plant length, biomass and chlorophyll contents have no significant change compared with the control at 10 mg·kg-1 Cd treatment, indicating a relatively high growth adaptation of S. orientalis. The ratio of chlorophyll a to chlorophyll b under Cd stress was not significantly different from that of the control, which contributed to the Cd tolerance of S. orientalis. With increasing Cd concentration, net photosynthesis rate(Pn), stomatal conductance(Gs), and transpiration rate(Tr) decreased, while intercellular CO2 concentration(Ci) increased 2.28%~7.83%, which suggested that the dominant reason for the decline of Pn was non-stomatal limitation. Moreover, the maximal photochemical of photosystemⅡ(Fv/Fm), ratio of photochemical quantum yield of photochemical of photosystemⅡ (ΦPSⅡ), rate of electronic transmission of photosynthesis(ETR) and photochemical quenching coefficient(qP) gradually decreased, but non-photochemical quenching coefficient(NPQ) increased compared with the control. Taken together, the results uncover that the change of Chl a/Chl b, Fv/Fm and NPQ might play important roles in photosynthetic adaptive ability and Cd tolerance. |
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