小麦幼苗对盐胁迫和水分胁迫的生理反应对比

以小麦幼苗为实验材料，研究等渗水分胁迫（PEG-6000）和盐胁迫（NaCl）对叶片相对电导率、丙二醛含量、可溶性糖含量、游离脯氨酸含量、叶绿素含量和PSII最大光化学量子效率（Fv／Fm）影响。结果表明，两种渗透胁迫下，与对照比较，小麦幼苗相对电导率和MDA含量显著升高，且等渗盐处理后，二者含量普遍高于水分胁迫，说明盐胁迫除对植物产生渗透胁迫外还存在离子毒害作用；两种渗透胁迫下，可溶性糖和游离脯氨酸含量普遍高于对照，等渗盐胁迫下可溶性糖含量普遍高于水分胁迫，而游离脯氨酸含量普遍低于水分胁迫，说明可溶性糖可能是盐胁迫下的一种主要渗透调节物质，而游离脯氨酸可能是水分胁迫下的主要渗透调节物质；两种渗透胁迫下，叶绿素含量和Fv／Fm普遍降低，等渗盐胁迫下叶绿素含量和Fv／Fm显著低于水分胁迫，这也可能是离子毒害和细胞脱水的累加作用所致。

Physiological responses of weat seedling to water and salt stress

Wheat seedlings were used to study the changes of relative electrical transmission rates of callus, Fv/Fm and contents of MDA, free proline, soluble sugar, chlorophyll under salt and water stress, in order to analyze the difference of leaves responses to water and salt stress. The results showed that relative electrical transmission rates of callus and contents of MDA increased under salt and water stress compared with control, when plants were under salt stress, the permeability of cytoplasm membrance and membrance lipid peroxidation increased compared with water stress, that maybe the effects of iron toxcity; Contents of free proline and soluble sugar increased under salt and water stress compared with control, but contents of soluble sugar was higher and contents of free proline was lower under salt stress than under water stress, that means soluble sugar was the main osmotic regulation under salt stress and free proline was the main osmotic regulator under water stress; Fv/Fm and contents of chlorophyll decreased under water and salt stress compared with control, and those were much more decreased under salt stress, that may also be co-effects of ion toxicity and cell dehydration.