Research Of Physiological Mechanism Of Jasmonic Acid Methylester Regulated Salt Resistance In Black Locust

Black locusts belong to Papilionaceae Robinia. It has been considered to be of particular interest because of its tough timber, richer nutrient material content and wider adaptability. It was a fine species for the improvement of salt resistance and alkali-resisted land. In this study we used diploid and tetraploid black locust as test materials. Three stresses (500mM NaCl,100μM MeJA, NaCl and MeJA) were adopted every5days, and before then sampled. We surveyed the anatomical structure of the black locusts, compared the differences of morphological structure and physiological and biochemical indicators as well as gene expression, between diploid and tetraploid black locust under different stresses. The point is to compare the changes of the two specises in the proceeding to adapt to salt environment, and also focused on the effects of MeJA. Aims to explain the plant salt-tolerance mechanism in-depth and interpret the impacts of exogenous MeJA on blact locusts. Hope to provide useful basis for later research and actual production.Salt injury symptoms of tetraploid black locust were lighter than that in diploid, while relative water content and chlorophyll content were higher. These phenomena indicate that diploid black locust was more sensitive to salt environment.The blade surface are covered with wax layer, guard cell edge thicken, palisade tissue be developed while spongy tissue be retrograded in black locusts. These structures make the transpiration loss less, in order to adapt to the environment of water scarcity. In tetraploid trichomes adhere to both upper and lower epidermis, but in diploid only upper epidermis. Tetraploid has less trichomes and more stomatal. The structure characteristics of tetraploid makes it more resistant than diploid.Higher antioxidant enzymes (POD, SOD, APX, MDHAR, DHAR and GR) activity in tetraploid can detoxify reactive oxygen species more quickly and more effective, in order to reduce the plasma membrane damage. In tetraploid the the structure of plasma membrane stabile, H+-ATPase activity higher, which can effectively reduce Na+absorption, and reduce the toxicity of ion. MeJA and ABA levels in tetraploid were higher than that in diploid, and qathe ABA as a signaling molecule can lead to downstream response faster. These strengths contributed to the salt resistance of tetraploid black locust.The impact of exogenous MeJA is similar to stresses: MeJA can promote reactive oxygen species accumulate, antioxidant enzymes activity increase. MeJA can improve the antioxidant enzymes activity may be due to that MeJA can ease the toxicity of NaCl.