Changes of Grapevine Photosynthetic Properties under Salt Stress

The photosynthetic properties of grapevine clone 8804 planted in the plastic pot in August,2004 were measured at the certain stage under the stress with different concentrations of salt(0,0.2%,0.4% and 0.6% NaCl)in the treated soil.The results showed that the net photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr) and the content of chlorophyll a(chl.a) and chlorophyll b(chl.b) changed similarly with increasing salt stress.They all dropped continually at the stress prophase,and then rose slightly for a few days.Afterwards,they dropped again rapidly at anaphase.Whereas intercellular concentrations of CO_2(Ci) unchanged almost at prophase,but fell sharply at anaphase.The findings indicated that the effect on grapevine photosynthesis through salt intimidating was a gradually conversion process,which varied from nonrestrictive of stoma to restrain of stoma.