Abstract: The early rice variety Zhongjiazao 17 was selected in this study to investigate the effects of salicylic acid （SA） and diniconazole （S08） combination on cold tolerance of rice plants at the seedling stage under the artificial climate chamber and field conditions. The results indicated that cold stress adversely damaged the rice seedlings, but such effect could be relieved when treated with SA+S08. Under cold stress, lower decrease in maximum fluorescence quantum efficiency（Fv/Fm） and the actual fluorescence quantum efficiency [Y（II）] of leaves was found in the SA+S08 treatment than those in H2O treatment. Accordingly, lower increase in contents of MDA and H2O2 was found in the former than the latter under cold stress compared with their respective controls under natural conditions. In contrast, larger increase in activities of SOD and CAT as well as soluble content was showed in plants treated with SA+S08 than those treated with H2O. Under filed conditions, the plant height of rice seedlings treated with SA+S08 decreased slightly compared with those plants treated with H2O. However, the dry matter weight in the former was higher than the latter. Therefore, we concluded that application of SA+S08 could enhance the antioxidant capacity of rice leaves to reduce oxidant stress caused by cold stress.

Key words: rice, SA+S08, cold stress, antioxidant capacity

摘要： 以早籼稻品种中嘉早17为试验材料，在水稻秧苗期分别于人工气候箱及大田进行低温处理，并喷施一定浓度的水杨酸（SA）和烯唑醇（S08）复配液，研究复配液对秧苗耐冷性的影响。结果表明，低温胁迫显著抑制秧苗生长，喷施适量的SA、S08复配液可有效缓解低温伤害。低温胁迫下，SA+S08处理的水稻叶片最大荧光量子效率（Fv/Fm）及实际荧光量子效率（Y（II））与常温下相比降幅较小，而喷施清水的处理降幅明显较大；低温胁迫下，秧苗叶片丙二醛（MDA）含量和过氧化氢（H2O2）含量均较常温下显著提高，但喷清水的处理提高的幅度显著高于SA+S08处理；低温胁迫下，秧苗叶片的可溶性糖含量、超氧化物歧化酶（SOD）活性及过氧化氢酶（CAT）活性较常温下均提高，喷清水的处理SOD活性较常温下提高不显著，而可溶性糖含量和CAT活性提高显著，而SA+S08处理这三者均显著提高，且显著高于喷清水处理。大田条件下，SA+S08处理的秧苗株高较喷清水处理有所下降，但差异不显著，而干物质量显著高于喷清水处理。鉴于此，笔者认为，水稻喷施SA、S08是通过提高叶片抗氧化能力，减轻低温下细胞膜过氧化伤害，提高叶片光合能力，促进有机物的合成，从而增强秧苗的耐冷性。

关键词: 水稻, SA+S08, 低温胁迫, 抗氧化能力