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| Effects of silicon on growth and physiological responses of rice seedlings under cadmium stress |
| Received:November 03, 2017 |
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| KeyWord:silicon;cadmium;rice;physiological response;ultrastructure |
| Author Name | Affiliation | E-mail | | LI Tian-zhe | College of Land and Environment, Shenyang Agricultural University, Shenyang 110866, China | | | CHEN Ai-ting | College of Land and Environment, Shenyang Agricultural University, Shenyang 110866, China | | | LI Cai | College of Land and Environment, Shenyang Agricultural University, Shenyang 110866, China | | | YANG Dan | College of Land and Environment, Shenyang Agricultural University, Shenyang 110866, China | | | HE Na | College of Land and Environment, Shenyang Agricultural University, Shenyang 110866, China | | | LIU Ming-da | College of Land and Environment, Shenyang Agricultural University, Shenyang 110866, China | mdsausoil@163.com |
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| Abstract: |
| The effects of silicon(Si) on growth and physiological responses of rice(Oryza sativa L. "Liaojing 9") seedlings under Cd stress were studied using a hydroponics experiment in which the effects of attendant cations had been eliminated. Four treatments were conducted with the initial content of 1 mg·L-1 Cd2+, except for the control group, and different contents of Si(0, 50, 100, 150 mg·L-1 SiO2). The results demonstrated that the growth of the rice seedlings was inhibited under Cd stress, and that Si significantly enhanced the dry weights of shoots and roots. Moreover, higher peroxidase(POD) activity and malondialdehyde(MDA) content were induced, whereas catalase(CAT) activity was inhibited under Cd stress. With the increase in Si content, the activity of POD gradually decreased(P<0.05), the activity of CAT gradually increased(P<0.05), and MDA content decreased(P<0.05). The ultrastructure of rice cells was damaged and plasmolysis occurred. We found blurred and disorderly arranged chloroplast particles and lamellae, broken mitochondrial membranes, and blurred ridge under Cd stress. Following Si application,(1) the cell structure of rice leaves was intact,(2) the number of starch granules in chloroplast increased,(3) the osmium granules decreased and became smaller,(4) the lamellae were gradually neat,(5) the number of mitochondria and ridges increased, and (6) the bilayer membrane structure gradually recovered. To sum up, exogenous Si application promoted the growth of rice seedlings under Cd stress. Moreover, it alleviated the stress physiology response, improved the cell ultrastructure, and enhanced the ability of rice seedlings to resist Cd toxicity. Under the experimental conditions, the best effect of cadmium stress alleviation in rice seedlings occurred when the amount of silicon applied was 150 mg·L-1. |
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