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.