| Blueberry belongs to Vaccinium spp of Ericaceae.The anthocyanins and other active substances in its fruits have great health care function.Planting blueberry has achieved considerable economic benefits in recent years.However,in china,the development of salinized soil in some areas and and the secondary salinization of soil under the condition of facility cultivation have restricted its development.There are few studies on salt tolerance physiology of blueberry,and its salt tolerance needs to be solved urgently.In this study,the blueberry in pot was used as the research object to carry out the salt simulation test.The plants were treated with two different concentrations of Na Cl and Na NO3 in order to observing the growing conditions.The salt tolerance threshold of the blueberry was defined through the determination of the growth of the cane and the growth and the physiological indexes.Results were as follows:1.Under the Na Cl and Na NO3 stresses,the length,coarseness and the new branches of the blueberry plant cane were affected.With the increase of concentration,the length and the increment of the cane showed a downward trend in general,while the number of the cane generated an upward trend.Under the same concentration treatment,Na Cl was more obvious than the Na NO3 stress.Na Cl and Na NO3 showed significant growth inhibition or plant death when the concentration reached 50 mmol/L and 75mmol/L respectively.Two kinds of salt stress showed similar chlorosis symptoms on leaves.2.The chlorophyll content of blueberry increased first and then decreased under the stress of Na Cl and Na NO3.The chlorophyll synthetic obstacle appeared in the middle of the stress treatment,which led to the decrease definitely of chlorophyll content,and then gradually decreased with the prolongation of treatment,the decrease scope was increased with the increase of concentration.The influence of Na Cl is greater than Na NO3 under the same concentration,3.In this study,the content of three kinds of organic osmotic substances,such as soluble protein,soluble sugar and proline were increased in the early stage of salt stress,which was obviously higher than that of the control.But with the prolongation of thetreatment,the accumulation of damage,and the blocking of The organic osmotic regulators under high concentration stress,the content of the three kinds of osmotic regulators were all declined in different degree.4.The cell membrane permeability of blueberry leaves added with the increase of salt concentration.Under the low concentration treatment,the plant can reduce the osmotic potential by accumulating organic matter continuously to maintain the balance of water potential and prevent the exosmosis of the cells.Under the high concentration treatment,the oxidative stress on the membrane was aggravated with the prolonged accumulation of the stress and the increase of the lipid peroxidation on the membrane,then the MDA increased,indicating the MDA would increase with the increase of treatment concentration and the prolongation of treatment time.5.In this study,the activity of SOD and POD increased obviously in the early stage of treatment.The increase of high concentration treatment was obviously greater than that of low concentration treatment.With the prolongation of the treatment,the high concentration of salt stress caused the inhibition of the biosynthesis of SOD and POD,the physiological activity decreased.Under the low concentration stress,the injury was lighter,because plant increased its own SOD and POD initiatively to inhibit the peroxidation caused by salt stress and to prevent the damage to membrane system.In conclusion,under the stress of Na Cl and Na NO3,blueberry plants showed different salt tolerance ability,and Na Cl had more influence on Blueberry than Na NO3.Considering the effect of salt stress on plant growth,survival and the changes of physiological indexes,the salt tolerance threshold of blueberry under Na Cl and Na NO3 stress was determined to be 50mmol/L and 75mmol/L respectively. |
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