采用不同浓度NaCl(0、0.1%、0.3%、0.5%)处理山葡萄品种‘左山二’幼苗,于盐胁迫20d时测定叶绿素荧光参数,盐胁迫25d时对0(CK)和0.3%NaCl溶液处理的植株进行叶片超微结构观察,以探讨山葡萄品种的耐盐机理。结果表明:(1)中度(0.3%)或重度(0.5%)盐胁迫下,山葡萄叶初始荧光(F0)显著升高,PSⅡ原初光化学效率(Fv/Fm)、PSⅡ潜在活性(Fv/F0)、光化学淬灭系数(qP)、实际光化学效率(ΦPSⅡ)、非光化学淬灭系数(NPQ)和电子传递效率(ETR)显著降低,表明叶片PSⅡ反应中心破坏,PSⅡ受体侧电子传递受害,通过热耗散散失过剩激发能的能力减弱。(2)中度盐胁迫条件下,叶绿体超显微结构较对照发生明显变化,其外形明显皱缩变短呈不规则球形,大的淀粉粒消失,质壁分离明显,基粒和基质片层界限模糊不清,被膜破损或解体,叶绿素内部质体小球增多,表明其形态结构已受到严重损伤。(3)盐胁迫处理下,山葡萄线粒体嵴排列紊乱,线粒体膜结构模糊不清或溶解,但未见明显的破裂现象,说明线粒体受害程度较叶绿体小,线粒体较叶绿体对NaCl相对不敏感。(4)盐处理下细胞核形态较对照发生改变,核膜溶解或消失,但未完全崩解,说明盐胁迫对细胞核造成了一定损伤。
The cuttings of Amur grape varieties(Zuoshaner)were treated with different concentrations of NaCl(0,0.1%,0.3%,0.5%),and chlorophyll fluorescence parameters of the cuttings were determined in 20th day after salt stress.The ultrastructure of the leaves were observed in 25th day under 0(CK)and 0.3% NaCl treatments to study the mechanism of salt tolerance in Amur grape.The results showed that:(1)At middle salt level(0.3%)or high salt level(0.5%)the minimal fluorescence(F0)increased significantly,while the photochemical efficiency(Fv/Fm),potential activities of PSⅡ(Fv/F0),photochemical quenching coefficient(qP),actual photochemical efficiency of PSⅡ(ΦPSⅡ),non-photochemical quenching coefficient(NPQ)and electron transport rate(ETR)all decreased significantly under the two stress conditions.The results suggested that the reaction center of photosystem Ⅱand the electron transport at the acceptor side were probably damaged,and the capacity of lose excess excitation energy through the heat dissipation was decreased.(2)Compared with CK,the ultrastructure of chloroplast had significantly changed under moderate stress.The shape was shortened and round,big starch grain disappeared,plasmolysis was appeared apparently,grana and stroma lamella were obscured.The capsule was damaged or disintegrated and the plastoglobulus in chloroplast increased.The ultrastructural observation showed that the morphological structure of chloroplast was seriously damaged.(3)It was observed that mitochondrial cristae of Amur grape arranged in disorder and mitochondrial membrane were obscured or dissolved,but had no obvious fracture phenomena under salt stress.The results indicated that mitochondria was harmed lightly and it was relatively insensitive to NaCl compared with chloroplast.(4)The nuclear morphometry was changed under salt stress.The nuclear membrane was dissolved or disappeared,but not completely disintegrated and it revealed the damage of nuclear caused by salt str