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作者	单位
李有芳，靖建国，张静悟，李卫华	（石河子大学农学院/新疆生产建设兵团绿洲生态农业重点实验室，新疆石河子 832000）

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中文摘要:

为了解DNA甲基化与小麦抗盐性的相关性，以耐盐性不同的春小麦品种新春11号（耐盐）和新春6号（盐敏感）为材料，利用DNA甲基化抑制剂5-氮杂胞苷（5-azaC）处理小麦种子7 d，并对处理后的幼苗用200 mmol·L^-1NaCl胁迫7 d，分析盐胁迫下DNA去甲基化小麦的农艺性状及生理特性变化。结果表明，盐胁迫抑制了小麦的生长。盐胁迫下DNA甲基化抑制剂处理可显著降低小麦株高，对穗长、穗粒数和穗粒重无显著影响。与单独盐胁迫相比，DNA甲基化抑制剂处理后，新春11号叶片净光合速率明显下降，蒸腾速率、气孔导度下降幅度减缓，胞间CO₂浓度无显著差异；新春6号蒸腾速率、气孔导度、胞间CO₂浓度显著下降，叶片净光合速率无显著差异。盐胁迫下DNA甲基化抑制剂处理可显著减少小麦叶片丙二醛（MDA）含量，显著提高新春6号小麦幼苗叶片中脯氨酸和可溶性糖含量，而对新春11号影响不大；显著提高新春11号过氧化物酶（POD）活性及新春6号超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性。综上所述，DNA甲基化抑制剂会导致小麦植株矮化，提高盐胁迫下小麦叶片的抗氧化能力，缓解盐胁迫负效应，小麦品种对DNA甲基化抑制剂的敏感性与其耐盐性有关，推测盐胁迫下小麦可能通过DNA甲基化调控其耐盐性。

英文摘要:

In order to study the correlation between changes in DNA methylation and salt resistance of wheat,Xinchuan 11(a salt-tolerant cultivar) and Xinchun 6(a salt-sensitive cultivar) were used as materials. Wheat seeds were treated with DNA methylation inhibitor 5-azacytidine(5-azaC) for 7 days,followed by treatment with 200 mmol·L^-1 NaCl for 7 days to analyze the effects of DNA demethylation on wheat growth and physiological indices under salt stress. The results showed that NaCl inhibited the growth of wheat. DNA methylation inhibitors significantly reduced wheat plant height after salt stress,resulting in dwarfing of wheat plants,but it had no significant effect on spike length,grains per spike and grain weight per spike. Compared with salt stress alone,after treated with DNA methylation inhibitor,the net photosynthetic rate(P_n）of Xinchun 11 decreased significantly; transpiration rate(T_r) and stomatal conductance(G_s)decreased slowly,and intercellular CO₂ concentration(C_i)had no significant difference. Meanwhile,T_r,G_s and C_i of Xinchun 6 decreased significantly,but there was no significant difference in P_n. DNA methylation inhibitor significantly reduced MDA content in wheat leaves under salt stress and increased the content of proline and soluble sugar of Xinchun 6 wheat seedlings,but had little effect on Xinchun 11. DNA methylation inhibitor significantly improved the activity of Xinchun 11 peroxidase(POD),superoxide dismutase(SOD) and catalase(CAT) of Xinchun 6. In summary,DNA methylation inhibitor 5-azaC caused dwarfing of wheat plants,improved the antioxidant capacity of wheat leaves under salt stress,so that alleviated the effects of salt stress on wheat. Wheat varieties with different salt tolerance showed different sensitivities to 5-azaC,which can be predicted that the change of salt tolerance of wheat may be affected by the regulation of DNA methylation.

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