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| Physiological response and Cd accumulation and distribution characteristics of wheat under Cd stress |
| Received:December 21, 2018 |
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| KeyWord:wheat;Cd;physiological response;accumulation;chemical form |
| Author Name | Affiliation | E-mail | | ZHANG Da-zhong | College of Agronomy, Northwest A & F University, Yangling 712100, China | | | YANG Hai-chuan | Agricultural Science Research Institute of Gaocheng District, Shijiazhuang City, Hebei Province, Shijiazhuang 052160, China | | | JIAN Ming-yang | College of Agronomy, Northwest A & F University, Yangling 712100, China | | | WEI Shu-wei | College of Agronomy, Northwest A & F University, Yangling 712100, China | | | ZHAO Yue | College of Agronomy, Northwest A & F University, Yangling 712100, China | | | ZHANG Yi-yang | College of Agronomy, Northwest A & F University, Yangling 712100, China | | | DING Qin | College of Horticulture, Northwest A & F University, Yangling 712100, China | dingqin@nwafu.edu.cn | | MA Ling-jian | College of Agronomy, Northwest A & F University, Yangling 712100, China | mlingjian@126.com |
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| Abstract: |
| Our investigation aimed to determine the morphological and physiological responses of wheat to Cd stress. We studied the morphological indexes, physiological indexes at multiple growth stages, total Cd content in various organs at maturity, and the proportion of Cd in each chemical form in order to characterize Cd absorption and accumulation, and determine the mechanism of Cd stress resistance in wheat. Potted experiments were carried out using four wheat cultivars with different Cd resistance. Three concentrations of CdCl2 (0 mg·kg-1, 25 mg·kg-1, and 50 mg·kg-1)were applied to the potted plants. Our results showed that the plant height and leaf area were less sensitive to Cd stress. The plant height of M1019 and the leaf area of Xinong 20, Xunong 186, and M1019 were enhanced by the 25 mg·kg-1 Cd treatment. The accumulation of absorbed substances was sensitive to Cd stress, and the dry weight of leaves decreased by more than 20% under treatment with 50 mg·kg-1 Cd. The high concentration Cd treatment showed an inhibition of the growth indices of wheat. Under a stress of 25 mg·kg-1 Cd, the activity of the POD enzyme in leaves increased, while under a stress of 50 mg·kg-1 Cd, the activity of the enzyme decreased. The activity of POD decreased with duration of stress. The activity of SOD in leaves decreased with increase in Cd concentration and time. The content of proline increased with increase in Cd concentration and time. The chlorophyll content decreased with increase in Cd concentration. With increase in Cd concentration, the Cd content of wheat increased, and its accumulation in each organ was found to be in the order root > leaf > stalk > seed. The Cd contents of Xunong 186 and M1019 were lower than those of Xinong 20 and Luomai 0603, and the Cd transport coefficients of the leaves and kernels of Luomai 0603 were the lowest at 21.0% and 2.2%, respectively. The highest Cd transport coefficient was for Xinong 20 (26.4%). The lowest Cd transport coefficient was found in Xunong 186 (3.0%). An analysis of the chemical composition showed that the sodium chloride and acetic acid extraction states accounted for the largest proportion of stress-related compounds, and this proportion increased with Cd concentration. The active Cd content ratio was lowest for Xunong and M1019. The results showed that various morphological and physiological indexes had different responses to Cd stress. Compared with sensitive cultivars, Cd absorption and accumulation in resistant cultivars were low and the proportion of Cd with higher activity in resistant cultivars was low. The mechanistic reasons for the differences in the response patterns of different wheat varieties to Cd stress require further study. |
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