Studies On Salt Resistance Of Four Tree Species (Eurya)

The two-year seedlings of Eurya alata,Eurya japonica,Eurya muricata,Eurya emarginata under different concentrations of NaCl were studied. And their growth indexes,physiological and biochemical characteristics were analysed systematically .The main conclusions were drawn as follows:(1) 0.2%,0.4% NaCl accelerated the growth in the height and biomass of Eurya emarginata and Eurya japonica , 0.6% NaCl restrained the growth in the height and biomass of all trees. Eurya emarginata under salt stress were all survival .A few of Eurya japonica died. The survival rates of Eurya alata under 0.6% NaCl were 45%. The trees of Eurya muricata all died under salt stress of 0.6% NaCl.(2) Under salt stress, Chla, Chla+b,Pn,Cond,Ci declined ,but Tr and WUE fluctuated.(3) Under salt stress, the selective Permeability of cell membrane increased. The extent of Eurya muricata was the largest of all. The tendency of MDA was similar with that of the selective Permeability of cell membrane.SOD activity of Eurya japonica and Eurya emarginata under salt stress increased tardily, especially for Eurya emarginata. SOD activity of Eurya muricata and Eurya alata were up firstly and down later.The free proline contents of Eurya alata and Eurya muricata increased ; that of Eurya japonica was up firstly down then, and declined later; that of Eurya emarginata declined firstly increased later. Under o.2% salt stress , the soluble sugar contents increased in the initial stage of salt stress, then declined with the continuation of salt stress; under 0.4% and 0.6% salt stress, the soluble sugar contents were down then increased. The soluble sugar content of Eurya emarginata was the highest, and that of Eurya muricata was lowest of all.Badly holding-back Na+ ability of stem and high-level Ca2+of root made Eurya muricata not bear salt stress. Well control-absorption of ion and keeping nutritional balance were the reason that Eurya muricata and Eurya alata had steady ion content and better salt resistance. Eurya muricata could not bear salt stress,and well maintained mineral nutritional balance。(4) NaCl had enhanced the activities of ATPase in plasmolemma and tonoplast of Eurya emarginata.Under salt stress,the activities of ATPase of Eurya japonica were up inapparently.(5) Based on the systematical and comprehensive analyses,the order of salt resistance ability for four species from the strong to the weak was Eurya emarginata >Eurya japonica>Eurya alata>Eurya muricata.