星星草耐盐碱生理机制再探讨

Further Study of Physiological Mechanism of the Saline-alkali Tolerance of Puccinellia tenuiflora

用不同浓度Na2CO3处理星星草幼苗,7d后测定叶片相对电导率、渗透势、光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)、蒸腾强度(Tr)、水分利用效率(WUE)等生理指标,以研究星星草抗盐碱的生理机制.结果表明,低浓度Na2CO3胁迫下,星星草幼苗可通过渗透调节来减轻细胞所受的伤害,因而膜透性受影响较小,相对电导率上升较少,而Gs基本保持不变,Pn、Tr还有所促进,WUE有所增加,这些结果说明,星星草幼苗对低浓度碱性盐具有一定抗性;但星星草幼苗的这种抗性有一定限度,随着Na2CO3胁迫浓度的增加,Gs、Tr、Pn依次受到抑制,最终膜透性急剧增加,说明星星草幼苗已受损严重,这些变化具有较强的顺序性.

Puccinellia tenuiflora seedlings were treated with Na2CO3 at different concentrations and the relative conductivity, osmotic potential, photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate and water use efficiency of their leaves were measured seven days later to study the physiological mechanism of the Saline-alkali Tolerance of P. tenuiflora. The results showed that treated with Na2CO3 at lower concentrations, P. tenuiflora could alleviate its cellular injury through osmotic regulation, so that the membrane permeability slightly suffered, the relative conductivity slightly increased, the stomatal conductance remained basically unchanged, the photosynthetic rate and transpiration rate improved and the water use efficiency increased. These indicated that P. tenuiflora seedlings had certain resistant capability to basic salts at lower concentrations but this resistant capability was limited to a certain extent; as the Na2CO3 concentration increased, the stomatal conductance, transpiration rate and photosynthetic rate respectively decreased and as a result the membrane permeability sharply increased, which revealed that P. tenuiflora seedlings suffered severe injury and these changes appeared in a very sequential order.