Effects Of Salt Stress On Photosynthetic Physiology And Growth Of Lycium Ruthenicum Murray

In this study,Black Wolfberry?Lycium ruthenicum Murray?clonal seedlings growing in Qaidam region has been chosen as a plant material to test for salt stress tolerance regarding growth rate,leaf cellular water retention ability,Photosynthesis response mechanism and variables in chlorophyll fluorescence parameters.By analyzing the plant responses to different levels of salinity stress,trial data will be contribute towards the mass production of Black Wolfberry in Qidam region,as well as reliable evidence for Black Wolfberry resource expansion in Qinghai Province.According to the study,following results have been concluded as listed:1.Under the condition of salt stress,with the increasing of experiment time,the growth status of Lycium barbarum L.was different.When the concentration reached500 mmol L^-1,there was serious water loss in leaves,and with the increase of salt stress,the growth of Lycium barbarum L.The relative plant height and relative basal diameter decreased.When the concentration was over 600 mmol L^-1,the plant was damaged irreversibly.2.Salinity stress impacts the plants negatively,the higher salt concentration,the more damage to the seedlings;the longer duration of the stress,the more recognizable negative changes of the plant.3.The leaf cellular water retention and anti-dehydration ability reduces when the salt stress concentration increases.The higher salt stress concentration,the more serious the water loss of the leaves,the lower the relative water content of the leaves,and the higher the water saturation loss of the leaves.Serious water retention ability reduces when the salt concentration exceeds 300 mmol·L^-1.4.Higher salt stress concentration,and longer stress duration time leads to considerable decrease of net photosynthetic rate,lower transpiration speed,and stomatal conductance degree.5.Low concentration of salt stress impacts the plant positively towards the water usage efficiency,which indicates a relatively high degree of elf-regulatory ability and adversity adaptability.However high salt stress concentration(?300 mmol·L^-1)deeply damages all aspects of the plants.The self-regulatory capacity of the plants was limited,and simply reducing transpiration could not reduce the water loss.6.With the increase of salt concentration,the net photosynthetic rate of Black Wolfberry was inhibited.Under low concentration of salt treatment,the response degree of Black Wolfberry was higher than the higher concentration treatment,and the higher the concentration,the lower the degree of the net photosynthetic response.Treatment with high salinity stress results in a decrease in stomatal conductance of Black Wolfberry,thus inhibiting transpiration.By reducing transpiration rate,plants water loss rate decreases as a result.7.The low concentration of salt stress barely had any effect on the potential activity of PSII,while high concentration of salt stress played a destructive role in the potential activity of PSII.The increase of salt stress concentration results in the dysfunction and irreversibility of the PSII reaction center,which leads to inhibited electron transport activity,lower intrinsic activity of plants,and a considerable degree of photoinhibition.