盐胁迫条件下杨树盐分与甜菜碱及糖类物质变化  

Genotypic Variation in Accumulation of Salt Ions, Betaine and Sugars in Poplar Under Conditions of Salt Stress

作　　者：陈少良[1] 李金克[1] 毕望富[1] 王沙生[1] 

机构地区：[1]北京林业大学生物学院森林生物实验中心,北京100083

出　　处：《植物学通报》2001年第5期587-596,共10页Chinese Bulletin of Botany

基　　金：国家自然科学重点基金 (3 983 0 3 2 0 )资助~~

摘　　要：以抗旱耐盐性强的胡杨 (Populuseuphratica)和非抗盐的群众杨 (P .popularis‘35 - 44’)为实验材料 ,研究了盐胁迫条件下盐分与甜菜碱、还原糖、蔗糖以及水溶性糖等细胞相容溶质的动态变化。两种杨树在盐处理期间表现出明显差异 :群众杨下部叶片首先表现出盐害症状 ,处理后两周苗木上部叶片也出现盐害并脱落。而胡杨在试验期间仅下部叶片发黄脱落 ,盐处理 1 5天后落叶量仅为 1 6%。群众杨盐害症状的出现主要是由叶片中盐离子的大量累积所致。与之比较 ,胡杨拒吸Na+的能力及控制Cl- 转运的能力均优于群众杨。另外 ,胡杨的耐盐性强于群众杨也与其有机溶质的变化有关。受到盐胁迫后胡杨根叶中甜菜碱浓度显著提高 ,在处理后 1 5天达到最高值 ,特别是叶片中甜菜碱的浓度提高了 2 4 3倍 ,达到 1 899.8μmol/L ,根中甜菜碱含量也增加了 9倍。此外 ,盐处理后胡杨叶和根中的还原糖、水溶性糖和蔗糖含量均呈明显上升趋势 ,分别在第 4天和第 1 5天达到峰值。与胡杨相反 ,耐盐性弱的群众杨在盐胁迫期间 ,叶中甜菜碱和糖含量并无显著提高 ,根中糖分水平还明显降低。由此可以得出结论 ,胡杨渗透调节能力高于群众杨 。Effects of NaCl on concentrations of salt ions, glycinebetaine, reducing sugars, sucrose and soluble sugars in one_year_old seedlings of a salt_tolerant poplar genotype, Populus euphratica and one_year_old rooted cuttings of a salt_sensitive genotype, P. popularis '35-44' were examined. Leaf burn symptoms appeared in old leaves of P. popularis after 4 days of exposure to salinity, and young leaves in the upper shoots exhibited leaf damage and abscised by day 15. In contrast, P. euphratica had only 16% leaf loss by day 15. Leaf necrosis of P. popularis was the result of excessive salt accumulation, and P. euphratica exhibited a greater ability to exclude Na + and to limit Cl - transport from roots to leaves under increasing salinity. In addition, genotypic variation of salt resistance was related to the accumulation of compatible solutes. Leaf betaine content of P. euphratica increased 244_fold on day 15, up to 1899.8 μmol/L, and a 10_fold rise was also observed in roots. Similarly, levels of reducing sugars, sucrose and total soluble sugars significantly rised and reached the maximum on day 4 (leaf) and day 15 (root), respectively. By contrast, betaine levels of P. popularis declined following salt stress and no significant rise of sugars was observed in leaves and roots during the period of salt stress. Therefore, we concluded that the accumulation of compatible solutes made contributions to salt resistance of P. euphratica .

关 键 词：盐胁迫 胡杨 群众杨 Na^+ Cl^- 甜菜碱 水溶性糖 还原糖 蔗糖 盐分 钠 

分 类 号：Q945.78[生物学—植物学]