NaCl及等渗PEG胁迫对番茄叶片光合特性及蔗糖代谢的影响

为了从碳水化合物生产及代谢的角度比较分析盐胁迫和水分胁迫影响番茄产量和果实品质的原因,以番茄品种辽园多丽为试材,分别采用等渗透势的NaCl和PEG6000模拟盐胁迫和水分胁迫,研究二者对番茄光合特性及叶片中糖代谢的影响。结果显示:等渗的NaCl和PEG胁迫导致番茄叶片的净光合速率下降,14 d内PEG处理下降的多一些,14 d后NaCl处理下降的多一些,但总体来说两处理间差异不大;等渗的NaCl和PEG胁迫降低了番茄叶片的气孔导度、胞间CO2浓度和蒸腾速率,增加气孔限制值;等渗的NaCl和PEG胁迫降低了番茄叶片中叶绿素a、b和总叶绿素含量,降低了叶绿素a/b,两处理间差异不大。等渗的NaCl和PEG胁迫下,番茄叶片中的果糖和葡萄糖含量较对照显著增加,PEG胁迫增加的幅度大于盐分胁迫;等渗的NaCl和PEG胁迫下,番茄叶片中的蔗糖和淀粉含量较对照有所降低,水分胁迫降低的幅度也大于盐分胁迫;等渗的NaCl和PEG胁迫增加了番茄叶片中的蔗糖转化酶活性,PEG胁迫增加的幅度大于NaCl胁迫。结果表明:NaCl和PEG胁迫均破坏了番茄叶片的光合机能,降低了光合作用效率,但二者间差异不大;NaCl和PEG胁迫改变了番茄叶片中的糖代谢方向,显著增加了淀粉和蔗糖的分解,提高了叶片中的果糖和葡萄糖含量,PEG胁迫对番茄叶片中糖代谢的影响显著大于NaCl胁迫。

Effect of NaCl and PEG Iso-osmotic Stresses on Photosynthetic Characteristics and Sucrose Metabolizing in Tomato Leaf

In order to compare and analyse the reasons of salt stress and water stress influence tomato yield and fruit quality from the perspective of carbohydrate production and metabolism,the tomato variety Liaoyuanduoli was used,the same osmotic potential of NaCl and PEG6000 was used to simulate salt stress and water stress,photosynthetic characteristics and sugar metabolism in tomato leaves of two treatment was studied.The results showed that:Iso-osmotic NaCl and PEG stresses cause reduced net photosynthetic rate of tomato leaf,within 14 d PEGl treatment reduced more than NaCl treatment,after 14 d NaCl treatment reduced more than PEG treatment,but,overall,little difference between the two treatment;Iso-osmotic NaCl and PEG stresses reduced stomata conductance,intercellular CO2 concentration and transpiration rate in tomato leaves,increased stomata limitation value;Iso-osmotic NaCl and PEG stresses reduced chlorophyll a,b and total chlorophyll content,decreased chlorophyll a/b in tomato leaves,little difference between two treatments.Under iso-osmotic NaCl and PEG stresses,the content of fructose and glucose increased significantly in tomato leaves compared with control,PEG stress increased more than salt stress,sucrose and starch content reduced in tomato leaves compared with control,water stress reduced more than salt stress;Iso-osmotic NaCl and PEG stresses increased activity of sucrose invertase in tomato leaves,PEG stress increased more than NaCl stress.The results show that:NaCl and PEG stress both destroyed tomato leaf photosynthetic function,decreased the efficiency of photosynthesis,but little difference between two treatments;NaCl and PEG stresses altered the direction of sucrose metabolism in tomato leaves,increased significant the decomposition of starch and sugar,increased the content of fructose and glucose,the impact of PEG stress on sucrose metabolism was significantly greater than NaCl stress in tomato leaves.