NaCl胁迫对互花米草光合作用及其参数的影响

Effects of NaCl Stress on Photosynthesis and Parameters of Spartina alterniflora

关键词:  光合作用  CO₂响应曲线  蒸腾速率  盐胁迫  互花米草

Key words:  photosynthesis  A-Ci curve  transpiration rate  salt stress  Spartina alterniflora

摘要:

以互花米草(Spartina alterniflora Loisel)为材料,研究不同盐浓度下其CO₂响应曲线及其参数的变化情况。结果表明,盐浓度100mmol·L^-1时,互花米草各项指标和参数达到最大值,预示此浓度比较适合其生长和繁殖;盐浓度高于300mmol·L^-1时,其CO₂响应(A-Ci)曲线、蒸腾速率(Tr)、气孔导度(Gs)、最大Rubisco羧化速率(V_cmax)和最大电子传递速率(J_max)显著低于对照组,表明高盐浓度对互花米草的生长产生了抑制作用。盐胁迫对互花米草Rubisco数量及活性和RuBP再生产生破坏的程度无差异,二者综合作用导致互花米草光合速率(A)的降低。较高盐浓度时,互花米草依然可以积极调整生存策略,如降低蒸腾速率,保持较高的水分利用效率(WUE)等以此保障生命活动的继续进行,为其进一步建立种群和扩散提供基础。

Abstract:

The A-Ci curve, transpiration rate (Tr), stomatal conductance (Gs), maximum carboxylation rates of Rubisco (V_cmax), maximum rate of photosynthetic electron transport (J_max) of Spartina alterniflora under different NaCl concentration stress were studied.The results indicated that all physiological parameters reached the maximum value when salt concentration was 100 mmol·L^-1, it predicted that the salt concentration was suitable for Spartina alterniflora.When salt concentration was higher than 300 mmol·L^-1, A-Ci curve, Tr, Gs, V_cmax, J_max was significant lower than ck group, so it could conclude that high salt concentration can inhibit the growth of Spartina alterniflora.However, Spartina alterniflora could change survival strategy in order to keep growing, for example, they can cut down Tr and keep a high WUE.To sum up, Spartina alterniflora have a high toleration for salt stress, so it can be a basic factor for establishing populations and pervasion.