| To explore the effect of exogenous histone deacetylase inhibitor trichostatin A(TSA)on the salt and alkali resistance of tobacco.In this experiment,tobacco seedlings K326 and NC89 were used as research objects.Four treatments of CK,TSA,NaCl and TSA+NaCl were set up in hydroponic experiments.The growth,photosynthetic system,antioxidant system and infiltration coordination system of tobacco seedlings were analyzed.And the effect of ion transport,in order to provide a theoretical basis for the cultivation of salinized tobacco seedlings.The main findings are as follows:TSA(1μmol·L-1)could promote the growth of tobacco seedlings under NaCI stress(150 m mol·L-1),increase the plant height and leaf area of tobacco seedlings,and break the growth of tobacco seedlings under salt stress.Inhibition of development.Under the salt stress condition of 150 m mol·L-1,exogenous application of TSA could significantly increase the dry weight and leaf water content of the seedlings,and significantly promote the growth of root morphology of tobacco seedlings(total root length,root volume,root surface area and average diameter).In addition,exogenous TSA also increased the root vigor of tobacco seedlings under salt stress.TSA(1μmol·L-1)can increase ascorbate peroxidase(APX)in ascorbate-glutathione cycle(AsA-GSH)of tobacco seedlings under NaCI stress(150 mmol·L-1),single Dehydroascorbate reductase(MDHAR),dehydroascorbate reductase(DHAR)and glutathione reductase(GR),ascorbate oxidase(AAO)activity,enhances the clearance of catalase(H2O2)by plants effectiveness.At the same time,the content of non-enzymatic antioxidants ascorbic acid(AsA)and glutathione(GSH)was increased,and the ratio of AsA/DHA and GSH/GSSG was increased,which promoted the accumulation of reduced antioxidants in tobacco seedlings and reduced the The content of aldehyde(MDA)and catalase(H2O2)slowed the production rate of superoxide anion(O2-),reduced the relative conductivity of seedlings,and slowed the damage of lipid membrane.TSA(1μmol·L-1)could promote the photosynthetic system of tobacco seedlings under NaCI stress(150mmo1·L-1).TSA alleviated the decrease of chlorophyll a,chlorophyll b,chlorophyll a+b,chlorophyll a/b and carotenoids in tobacco seedlings due to salt toxicity,and increased the photosynthetic capacity of tobacco seedling leaves.In addition,there were differences in sugar accumulation and distribution between the two varieties under salt stress,and K326 transported more sucrose to the root system.While NC89 will accumulate more sucrose in the leaves.In addition,salt stress caused a large accumulation of ammonium nitrogen in the leaves and roots of the two varieties,and the synthesis of amino acids was slow.The application of TS A increased the carbon and nitrogen coordination ability of tobacco seedlings under salt stress,increased the content of photosynthetic products such as sucrose and fructose,accelerated the accumulation of ammonium nitrogen,and accumulated the necessary nutrients for the growth of tobacco seedlings.substance.TSA(1μmol·L-1)can promote the osmotic coordination ability of tobacco seedlings under NaCI stress(150mmo1·L-1).TSA increased the content of proline,soluble sugar,soluble protein and free amino acid in tobacco seedlings under salt stress,accumulated soluble substances,decreased intracellular osmotic potential,and maintained normal absorption of water.Exogenous TSA alleviated the ionic toxicity of salt stress on tobacco seedlings,significantly increased the accumulation of K+,Ca2+and Mg2+ in tobacco seedlings,significantly reduced the accumulation of Na+and decreased the ratio of Na+/K+and Na+/Ca2+.In addition,exogenous TSA can affect the selection coefficient of K+,Na+ absorption and transport in different organs of tobacco seedlings.Both of them reduced the SK,Na and SCa,Na in different parts of the two varieties,which could transfer and reduce the Na toxicity accumulated in the roots and alleviate the toxicity of ions to the roots of the plants. |
