In order to discuss the effect of salicylic acid (SA) and brassinolide (BR) on growth and drought resistance of cauliflower seedlings, the cauliflower cultivar, Xuefeng was used as the material, different concentrations of SA and BR were applied to the whole seedlings by foliar spray when the fourth true leaves were expanded fully and treated with drought stress in pot experiment, with sterile deionized water alone as control. The results showed that SA and BR increased the index of high quality seedlings, DW - FW percent of top, root-shoot ratio, photosynthetic rate, stomatal conductance, transpiration rate and chlorophyll content and promoted high quality seedling forming of cauliflower seedlings, but had no effect on intercellular CO2 concentmtion. The SA concentration with the best effect was 50 mg/L and BR was at 0.01 mg/L. Under drought stress, 50 mg/L SA and 0.01 mg/L BR obviously alleviated the decline of soluble protein content, increased SOD activity, decreased POD activity, and alleviated the accumulation of proline and MDAin cauliflower seedlings' leaves. It was concluded that application of exogenous SA and BR could improve growth status of cauliflower seedlings and alleviate the cauliflower damage by drought stress to some extent, and the 50 mg/L SA and 0.01 mg/L BR were the optimal concentration for cauliflower seedlings under this experimental condition.%为了探讨外源水杨酸(SA)、油菜素内酯(BR)对花椰菜幼苗生长及抗旱性的影响,以花椰菜品种雪峰为材料,采用盆栽法,于幼苗第4片真叶展开时,分别喷施不同浓度SA和BR溶液,并进行干旱胁迫,清水处理为对照.结果表明,一定浓度的SA、BR处理均可提高壮苗指数、地上部干物质含量、根冠比及净光合速率、气孔导度、蒸腾速率和叶绿素含量,促进壮苗的形成,改善生长状况,但对胞间CO2浓度无作用.干旱胁迫下,50 mg/L SA和0.01mg/L BR可以有效减缓干旱胁迫后的花椰菜幼苗叶片可溶性蛋白质含量下降趋势,提高超氧化物岐化酶(SOD)活性,降低过氧化物酶(POD)活性,减缓脯氨酸(Pro)和丙二醛(MDA)的积累,在一定程度上减轻干旱胁迫对花椰菜幼苗造成的伤害.本试验条件下,SA和BR最适宜的喷施浓度分别是50 mg/L和0.01 mg/L.
展开▼
