用2个耐盐水稻品种和2个盐敏感型水稻品种为材料,研究盐胁迫对水稻植株生物量积累、光合特性等生理特性的影响。结果表明,在盐胁迫条件下,耐盐水稻品种和盐敏感型水稻品种地上和根系的干鲜质量均呈下降趋势,其中,以盐敏感型水稻品种的地上部鲜质量与根系干质量的下降最为显著。盐胁迫条件下,水稻叶片的净光合速率(Pn)、气孔导度(Gs)、蒸腾作用(Tr)和表观叶肉导度(AMC)均呈不同程度的下降趋势。其中,耐盐水稻品种Pn、Gs、Tr和Pn/Ci的下降均低于盐敏感型水稻品种。同时,耐盐品种水分利用效率(WUE)也高于盐敏感型品种。盐胁迫条件下,耐盐水稻品种和盐敏感型水稻品种的胞间二氧化碳浓度(Ci)变化并不明显,气孔限制百分率(Ls)均较低,品种间差异也不显著,而表观叶肉导度显著下降,由此推测盐胁迫条件下Pn的下降并非因为气孔的限制,而与RuBPCase活性的下降有关。盐胁迫条件下水稻叶片和根系的渗透性调节物质脯氨酸、总氨基酸和可溶性糖含量上升,其中以可溶性糖含量上升最为显著(P〈0.01)。盐胁迫下叶片保护酶SOD、POD和CAT活性增强,膜透性增强,丙二醛含量增加,同时,根系活力下降。
With two salttolerant rice varieties and two saltsensitive varieties as material, the influence of salt stress on plant biomass accumulation, photosynthetic characteristics and the other physiological characteristics was studied. The results showed that the dry weight and fresh weight of shoot and root of salttolerant rice varieties and saltsensitive varieties were declined under salt stress. The fresh weight of shoot and dry weight of roots were declined significantly. The net photosynthetic rate, stomatal conductance, transpiration and apparent mesophyll conductance were declined to different degrees under salt stress. The drop of Pn, Gs, Tr and Pn/Ci of salttolerant varieties was less than saltsensitive varieties. The water use efficiency(WUE) of salttolerant varieties was higher than that of saltsensitive ones at the same time. The intercellular CO2 concentration (Ci) of salttolerant varieties and saltsensitive ones was not changed obvirously under salt stress. The stomatal limitation percentage (Ls) under salt stress was low and the difference among the varieties was not significant. And apparent mesophyll conductance (Pn/Ci) was changed significantly. The decline of Pnresulted from the decline of RuBPCase rather than from stomatal limitation. The permeability regulation substance contents of leaf and root such as soluble sugar and proline, total amino acids were increasd under salt stress with significant increase in soluble sugar contents (P 〈 0.01). The protective enzyme SOD, POD and CAT activities were enhanced, as well as the membrane permeability and the MDA content, the root vigor was declined under salt stress.