盐胁迫下白蜡和小胡杨光合生理日变化的响应研究

以小胡杨、白蜡盆栽苗木为试材,分析其在不同盐分浓度下的光合速率、蒸腾速率、气孔导度等光合生理特征的日变化动态。结果表明:在轻度盐浓度下,白蜡的光合速率、蒸腾速率、气孔导度日变化均呈单峰型,而小胡杨则呈双峰型,白蜡和小胡杨的光合速率最大值均出现在8:00～10:00之间,白蜡的最大值为CO29.4364μmol.m-2.s-1,低于小胡杨的CO216.304μmol.m-2.s-1,但二者的水分效率相接近;在中度盐浓度下,白蜡光合速率日变化由单峰型变为双峰型,小胡杨则仍为双峰型,白蜡光合速率最大值仍出现在8:00～10:00之间,而小胡杨则出现在14:00～16:00之间,白蜡的最大光合速率为CO25.6575μmol.m-2.s-1,比轻度盐胁迫的下降了40%,小胡杨为CO24.352μmol.m-2.s-1,比轻度盐胁迫的下降了73.3%,二者水分利用效率也基本接近。

Effect of Salt Stress on Photosynthetic Diurnal Variation of Fraxinus chinesis and Populus simonii × P.euphrati Seedlings

The Fraxinus chinesis and Populus simonii×P.euphrati seedlings were used as experimental material to study the effect of salt stree on the photosynthetic diurnal variation.The results showed that the photosynthetic rate,transpiration rate,stomatal conductance diurnal variation of Fraxinus chinesis showed a single peak type,while Populus simonii×P.euphrati was double peak type under mild salt stress.The maximum value of photosynthetic rate of Fraxinus chinesis and Populus simonii×P.euphrati Seedlings all appeared at 8:00-10:00,the maximum value were CO29.4364 μmol·m-2·s-1 and CO216.304 μmol·m-2·s-1 respectively,but the water use efficiency were close.In moderate salt stress,the photosynthetic rate diurnal variation of Fraxinus chinesis was double peak type,while Populus simonii×P.euphrati was single peak type.The maximum value of photosynthetic rate of Fraxinus chinesis seedlings appeared at 8:00-10:00,while Populus simonii×P.euphrati seedlings appeared at 14:00-16:00.The maximum photosynthetic rate of Fraxinus chinesis was CO25.6575 μmol·m-2·s-1 decreased 40% than that of mild salt stree,the maximum photosynthetic rate of Populus simonii×P.euphrati seedlings was CO24.352 μmol·m-2·s-1 decreased 73.3% than that of mild salt stree,but the water use efficiency also were close.