Study On Selection And Mechanism Of Salinity-tolerance Shrub Willow Germplasm

In this paper, the salinity-tolerance of 310 shrub willow hybrid clones and 32 shrub willow stock clones under NaCl solution culture was researched, 6 salt-tolerant shrub willow germplasm were selected, including 5 shrub willow hybrid clones(2555, 2610, 35-10, 2667, 3636) and 1 shrub willow stock clones(P1024). The effect on growth form, bio-membrane, enzymic, organic osmolytes and mineral elements of shrub willow clones under different concentrations NaCl stress were studied. The main points were summarized as follows:1. Selection of salinity-tolerance shrub willow germplasmUnder 0.5% NaCl stress, 10 shrub willow hybrid clones and 3 shrub willow stock clones which have higher ability of salt tolerance were selected. Under 1.2% NaCl stress, 5 shrub willow hybrid clones(2555, 2610, 35-10, 2667, 3636) and 1 shrub willow stock clones(P1024) which have strong tolerance under salt stress were selected.2. Effect on growth of shrub willow clones under different concentrations NaCl stressThere was significant effect on growth of 6 shrub willow clones under 0.6%, 0.8%, 1.0% and 1.2% NaCl stress. With the increasing of NaCl concentration, the biomass and relative water content were decreased in 6 shrub willow clones, and the root shoot ratio was increased.3. Effect on physiology and biochemistry of shrub willow clones under different concentrations NaCl stress(1) Effect on chlorophyll contents: With the increasing of NaCl concentration, chlorophyll contents, chlorophyll a contents and chlorophyll b contents were decreased in 6 shrub willow clones, but chlorophyll a contents of 2555 in Midterm stage and later stage and 3636 in later stage were increased.(2) Effect on bio-membrane system: MDA contents of 6 shrub willow clones were increased with the increasing of NaCl concentration.(3) Effect on enzymic system: With the increasing of NaCl concentration, SOD contents of 2555, 2667, 3636 and P1024 were increased, but SOD contents of 2610 and 35-10 were decreased; POD contents of 2667 and 3636 were increased and POD contents of 2555 were increased firstly and decreased later, but POD contents of 2610, 35-10 and 2667 were decreased.(4) Effect on organic osmolytes: Soluble protein contents, soluble suga contents and proline contents of 6 shrub willow clones were increased with the increasing of NaCl concentration, but soluble protein contents of 2555 and P1024 were decreased.4. Effect on mineral elements of shrub willows under different concentrations NaCl stressWith the increasing of NaCl concentration, Na+ contents and K+ contents of shoot of 6 shrub willow clones were increased and K+ contents of root were decreased; Mg2+ contents were increased except the shoot of 35-10 and Ca2+ contents were increased except 3636.5. Salt tolerance evaluation and salt tolerance index selection of shrub willowsPrincipal component analysis and subordinate function method were used to evaluate the salt-tolerance of shrub willow clones(2555, 2610, 35-10, 2667, 3636, P1024), the D value of 6 shrub willow clones was 0.0705, 0.1045, 0.0945, 0.0630, 0.0780, 0.0855, as the result, the order of salt-tolerance was 2610>35-10>P1024>3636>2555>2667.