硅对盐胁迫下库拉索芦荟叶绿素荧光参数和叶绿体超微结构的影响

 以7叶龄幼苗为试材, 研究了可溶性硅( Si) 对盐(NaCl) 胁迫下库拉索芦荟(Aloe vera L. )叶绿素荧光参数和叶绿体超微结构的影响。结果表明, 随处理时间延长, 芦荟对NaCl (100 mmol/L) 胁迫的响应愈加明显, 胁迫30 d的伤害明显重于10 d, 但NaCl胁迫下加Si (2.0 mmol/L) 与不加Si相比, 叶绿素(Chl1) 总含量下降幅度小, Chl1a含量显著提高, 叶绿素初始荧光( Fo) 值的上升与可变荧光( Fv)值的下降受到抑制, 光系统Ⅱ ( PSⅡ) 潜在活性( Fv/Fo) 显著增强, 同时, 加Si有利于保持盐胁迫下芦荟叶绿体的形态, 保护类囊体的超微结构, 说明施Si缓解盐胁迫对光合细胞器的伤害, 可改善盐胁迫下芦荟的光合作用。

Effects of Silicon on Parameters of Chlorophyll Fluorescence and Ultrastruc ture of Chloroplast in Aloe vera L. under Salt Stress

Effects of soluble silicon ( Si) on parameters of chlorophyll fluorescence and ultrastructure ofchlorop last in A loe vera L. under salt stress were investigated with seven2leaf2old seedlings. Experimental results showed that the responses of aloe to NaCl (100 mmol/L) stress were more evident with p rolongation oftreatment time; salt injury of 30 d after treatmentwasmore serious than that of 10 d. However, compared withthe p lants treated with NaCl alone, under NaCl stress with added Si ( 2.0 mmol/L ) , the decrease of totalchlorophyll content slightly decreased, chlorophyll a content significantly increased, the increase of minimalfluorescence ( Fo) and the decrease of variable fluorescence ( Fv) were inhibited, and the potential activity ofphotosystemⅡ ( PSⅡ) , i.e. Fv/Fo ratio was significantly enhanced. Meanwhile, added Siwas favourable tomaintain the morphology and structure of aloe chlorop last and to protect the integrity of thylakoid structure, illustrating that exogenous soluble Si alleviates injury of salt stress to photosynthetic organelle and imp roves photosynthetic efficiency of salt-stressed aloe plant.