NaCl胁迫对互花米草细胞膜和光响应曲线特征参数的影响

以大米草的互花米草为材料,研究了不同盐浓度对其细胞膜透性、丙二醛(MDA)含量和光响应曲线的特征参数的变化情况。结果表明:盐浓度低于300mmol·L-1时,互花米草细胞膜透性和MDA含量较对照组无显著差异;其较高的最大光合速率(>30μmol·m-2·s-1),表观量子效率(>0.05mol·mol-1Photons)以及较低的暗呼吸速率(<1.5μmolCO2·m-2·s-1)和光补偿点(<20μmol·m-2·s-1)为其有机物质积累、竞争、建立种群并扩散提供条件。盐浓度高于500mmol·L-1时,互花米草膜透性和MDA含量显著上升,最大光合速率(Amax)及表观量子效率(Q)显著下降,暗呼吸速率(Rday)和光补偿点(LCP)上升。表明细胞膜和光合作用有关酶受到迫害,抑制了其正常生长。盐胁迫下互花米草光合速率降低,但蒸腾速率的显著下降提高了单叶水分利用效率,从而部分缓解了渗透势变化对细胞的迫害,为其生存和生长提供条件。

Response of cell membrane and light-response curve parameters of Spartina anglica to NaCl stress

This research covers the study of light-response curve parameters,membrane permeability and malondialdehyde contents of Spartina anglica in NaCl salt stress.The results indicated that there was no significant change in membrane permeability or malondialdehyde contents at the salt concentrations no higher than 300 mmol·L-1.In the same condition,the relative high Amax(>30 μmol·m-2·s-1) ,high apparent quantum yield(>0.05 mol·mol-1Photons) ,relative low dark respiration rate(<1.5 μmol CO2·m-2·s-1) as well as light compensation point(<20 μmol·m-2·s-1) could be prerequisites for organic matter accumulation,competition,establishing populations and pervasion.However,at the salt concentration higher than 500 mmol·L-1,the member permeability and malondialdehyde contents increased obviously,Amaxand apparent quantum yield decreased significantly,and dark respiration rate and light compensation point increased slightly.All these changes showed that cell membrane and enzyme of photosynthesis of S.anglica was damaged,so their growth was inhibited.In addition,relative lower photosynthetic rate and significantly lower transpiration rate of S.anglica under salt stress provided the conditions for their existence and growth by higher water use effective and remission of persecution of osmotic potential to cell membrane.