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Effect of calcium on the cold-resistance of rice seedlings

Li Meiru, Liu Hongxian, Wang Yirou, Zeng Shaoxi, Guo Junyan

South China Institute of Botany, The Chinese Academy of Sciences. Guangzhou 510650, Guangdong

Abstract

Rice seeds submerged in CaCl_(2)30 mmol/L solution for one day were used as experimental material. By comparing the contents of endogenous antioxidants (GSH and AsA), the activities of membrane protecting enzymes (SOD, CAT and POD), and the content of soluble proteins before and after chilling stress and on the 3fh day of recovery, the mechanisms by which Ca affects cold resistance of rice seedlings were studied. The results indicated that treatment with CaCl_(2) increased the survival rate of seedlings after cold treatment at 1℃ and under a PFD of 150 #mu#mol m~(-2) s~(-1) for 2 d. Treatment with CaCl_(2) increased the content of Ca in the leaves, especially that of combined Ca; It also increased the contents of GSH and AsA, reduced the extent of decline of GSH and AsA caused by chilling stress and kept the contents of GSH and AsA as high as those in normal seedlings during the recovery period; The activities of CAT, SOD and POD were increased by CaCl_(2) and kept at high levels after chilling and the recovery period, in a manner similar to that of GSH and AsA. The content of boiling-stable protein was higher in CaCl_(2)-treated leaves than in untreated ones before and after chilling treatment, and expecially after recovery for 3 d, when it increased in CaCl_(2)-treated leaves but decreased in untreated leaves. By SDS-PAGE analysis, It was found that CaCl_(2) increased significantly the content of the large molecular weight (>67 kD) protein in both unstressed and stressed seedlings, and increased the content of small molecular weight (<17.5 kD) protein during recovery period. Therefore, the authors suggest that the alleviation of chilling injury by treating with CaCl_(2) could be associated with the enhancement of protective ability of the cell.

Key words: Calcium;Rice seedlings;Membrane-protective enzymes;Endogenous antioxidants;Boilingstable protein;Chilling stress

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Citing This Article:

Li Meiru, Liu Hongxian, Wang Yirou, Zeng Shaoxi, Guo Junyan. Effect of calcium on the cold-resistance of rice seedlings. Acta Physiol Sin 1996; 48 (4): (in Chinese with English abstract).