Study On Salt-tolerance Mechanisms And Resistance Breeding Of Main Popular Varieties In Westward Northeast

There are over 300 million mus saline uncultivated lands and 100 million salinized soil, which accounts Cor 25% of the total arable lands and is a huge soil resource. Engineering measures, with fast and less results hut high expense and degeneration of the soil were mostly adopted to ameliorate and utilize the saline lands in past years. Among the ameliorating measures, biological measure is fast and less expenditure one for enhancing the resistance of the plants. But now, more studies on crop salt-resistance or salt-tolerance have been done compared to woody plants. For trees, more researches about the salt resistance capacity of halophytes have been done. So, the salt resistance capacity and salt tolerance mechanisms of main popular varieties in westward northeast, the breeding of new salt-tolerance strains by means of chemical treatments of EMS and genetic transformation technology have been studied in detai 1 in this thesis. The main results were as follows:1. Effects of salinity on seedlings growth, ionic distribution within the plant, pigment content, accumulate of all sorts of permeational regulate matter, membrane oxidation, protein and enzyme etc. were examined for main popular varieties in westward northeast to determine the physiological reaction at various salt-alkaline stress. The results showed that all the responded varieties were as follows: with the increasing salt concentrations and pH, all physiological indices were changed regularly. The capability of adapting and salt-tolerance of varieties were evaluated synthetically.2. salt-resistant mutant selection and obtain of P. XBailin~l were studied firstly. The salt-resistant mutants were differentiated, rooted and formed from resistant callus that can be growth at 0. 8% NaCl. Cal I us growth, cal lus livabi I i ty and growth at NaCl stress, appropriate content of induce agent EMS, separation and differentiation of callus-resistant, salt resistance test of the plant in vitro of somatic salt-resistance mutants and so on were worked over. In addition, inorganic and organic osmotic regulation matter of callus and adventitious shoots were explored.3. The transgenic plants were obtained by Agrobtic Cerium-mediated and gene-gun transfer system. PCR detection and southern blotting showed that salt resistant gene was transferred and integrated into Populus sitnonHP. nigrn genome. In selecting differentiation medium, the leaf differentiation rate of transgenic plants over 8*1. 44%. Carbenici11 in was selected as an appropriate antibiotic to get rid of Agerobacterium turn fad ens on the explants after gene transformation. Kanamycin can be used as selecting agent for transformation cell. Its best concentrations were been decided.