NaCl胁迫对互花米草细胞膜和光响应曲线特征参数的影响

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

关键词:  互花米草  膜透性  MDA  光响应曲线  参数

Key words:  Spartina anglica  membrane permeability  malondialdehyde  light response curve  parameters

摘要:

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300 mmol•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(＞30 μmol•m 2•s 1)，表观量子效率(＞0.05 mol•mol 1Photons)以及较低的暗呼吸速率(＜1.5 μmol CO2•m 2•s 1)和光补偿点(＜20 μmol•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500 mmol•L 1时，互花米草膜透性和MDA含量显著上升，最大光合速率(Amax)及表观量子效率(Q)显著下降，暗呼吸速率(Rday)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。

Abstract:

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 Amax(＞30 μmol•m 2•s 1)，high apparent quantum yield(＞0.05 mol•mol 1Photons)，relative low dark respiration rate(＜1.5 μmol CO2•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，Amaxand 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.