中文摘要：

以龙眼胚性愈伤组织LC2细胞系为材料，研究聚乙二醇（PEG）、甘露醇和蔗糖等渗透胁迫对龙眼胚性愈伤组织SOD酶活性的影响．结果表明：与对照相比，随着PEG胁迫强度的增加，SOD活性在轻度（10g·L-1聚乙二醇）、中度（20g·L-1聚乙二醇）胁迫下上升，严重（30g·L-1聚乙二醇）胁迫下呈快速下降趋势；随着甘露醇浓度的提高，SOD活性不断升高，且一直维持在一个较高的水平上，直到浓度达到100g·L-1时才开始呈现缓慢下降的趋势；随着蔗糖浓度的升高，SOD活性不断升高，直到蔗糖浓度为70g·L-1时开始下降，70—90g·L-1之间的SOD活性下降缓慢．甘露醇和蔗糖处理比聚乙二醇处理的SOD活性高，下降的速度也较缓慢，说明适当高浓度的甘露醇和蔗糖，可以有效提高植物细胞活力，延缓细胞衰老．

英文摘要：

Line LC2 of longan embryogenic callus was used as material to study the effects of osmotic stress of PEG, mannitol, and sucrose on SOD activities in the embryogenic callus of longan. The results showed that： compared with the control, the activities of SOD ascended under low （10 g . L-1PEG） and middle （20 g . L-1 PEG） stress treatment with the increase of the extent of PEG stress, while it showed a rapid downtrend under high （30 g . L-1 PEG） stress treatment. As the extent of mannitol stress increased, the activities of SOD ascended continuously, and kept in a higher level, while it showed a slow downtrend under 100 g . L-1 stress treatment. As the extent of sucrose stress increased, the activities of SOD ascended continuously, then descended under 70 g . L- 1 stress treatment, it showed a slow downtrend under 70-90 g . L-l stress treatment. The activities of SOD under mannitol and su- crose treatment were higher than that under PEG treatment, and it showed a slow downtrend. It has been proved that the activities of the plant cell ascended continuously and the senescence of ceils delayed under appropriate concentrations of mannitol and sucrose. The above results can provide important information for the application of in vitro preservation technology in longan embryogenic cal- lus and the improvement of drought resistance in longan.