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Lanzhou University (2021)

Preliminary Study on Maintenance Mechanism of Water Balance in Reaumuria Soongorica under Salt and Drought Conditions

苏家豪

Titre : Preliminary Study on Maintenance Mechanism of Water Balance in Reaumuria Soongorica under Salt and Drought Conditions

Auteur : 苏家豪

Grade : Master 2021

Université : Lanzhou University

Résumé partiel
Drought and salinization are important factors restricting agricultural production.The xero-halophytic plant has been living in the harsh environment,such as the Gobi Desert,for a long time.And those plants possess unique salt-resistant and drought-tolerant mechanisms.Studies on those mechanisms will provide a theoretical basis for the improvement of stress resistance in forages and crops.Reaumuria soongorica is an extremely salt-tolerant and drought-resistant semi-shrub species of Tamarix,and is widely distributed in northwest China as the dominant species in desert vegetation.Our previous studies found that,there are always Na+efflux and H+infflux on salt glands of R.soongorica under Na Cl stress and osmotic stress.Especially under osmotic stress,even if there is only trace amount of Na+in the medium,the flow rates of Na+and H+on the surface of salt glands showed significant increase.Moreover,drought stress induced the increase of salt secretion from R.soongorica,and addition of extral Na Cl significantly alleviated the adverse effects from drought on R.soongorica.However,although salt secretion significantly increased under salt and drought treatments,the tissue water content of the R.soongorica did not show a significant change,suggesting that the R.soongorica might develop a special water regulation mechanism,which helps R.soongorica in maintaining water balance under salt and drought conditions.However,the understanding of this mechanism is still not clear and needs further study.Therefore,based upon previous studies,this study preliminarily explored the water transport and the change pattern of water potential gradient among different R.soongorica tissues by measuring the physiological indexes such as biomass,ion content and water potential in each tissue of R.soongorica under Na Cl and drought conditions.Then the c DNAs of some aquaporin genes which involved in water transport were cloned.The expression patterns of these genes were analyzed,and functional verification as well as subcellular localization of above genes were also analyzed.The main results are as follows:1.R.soongorica has a strong salt tolerance.50 mmol/L Na Cl treatment promotes the growth of R.soongorica seedlings.Under 300 mmol/L Na Cl,the plants could still survive though their growth were reduced.After being treated with different concentrations of Na Cl,both the tissue water content and relative water content of R.soongorica seedlings were maintained at the level of control.2.Under control and Na Cl treatments,the distribution of osmotic adjust substances in R.soongorica seedlings showed the trend that the most in stem,less in leaf,and the least in root.With the increase of Na Cl concentration,the contents of osmotic adjusting substances in stem and leaf were also increasing.

Mots clés : Reaumuria soongorica ;Salt treatment ;Drought treatment ;Water potential gradient ;Aquaporins;

Présentation (CNKI)

Page publiée le 17 novembre 2021