A Preliminary Study On Drought-resistance Of Native Elymus Sibiricus Germplasms Resources From The Northwest Plateau Of Sichuan Province

Based on observation of physiology and biochemistry,growth characteristics,biomass and other indicators,drought-resistance of 9 native Elymus sibiricus accessions from northwest plateau of Sichuan province for the test materials with E.sibiricus cv Chuancao No.2 and E.nutans Gannan for control materials,were studied under drought stress in the germination period,seedling stage to flowering stage.On the basis of identification important indicator of drought resistance for E.sibiricus,membership function analysis of materials for drought resistance test used for carried out a comprehensive evaluation.Main findings of the study are as follows:1.The increase range of germination rate when PEG treatment was 20%,and germination rate of SAG204059 under 20%(T2) osmotic stress was higher than the control (CK) 26.09%.For most of these materials,germination potential and germination index decreased along with stress concentration increasing,in which thelarges increase range was 73.33%and 26.96%.2.For the test materials,the growth of the early embryo was affected about 15%by stress graetly,with the exception of 96h germ long of SAG205158 by drought stress.The others for the test materials increased with the infiltration by the inhibition concentration deepened,SAG204155 and E.nutans Gannan under 20%osmotic stress had no germ in 96 hours.The range of germ length,radicle length,number of radicle were 71.35%～153.70%,116.45%～164.45%,69.23%～130.00%under 20%stress.Drought-resistant such as E.nutans Gannan,SAG204059 were significantly higher than under 0%in these indexs.3.Early in natural drought stress,the activities of superoxide dismutase(SOD),peroxidase(POD)and the contents of chlorophyll index(Chl) higher than its own CK.But then appeared declining tend as long as the stress lengthening.The contents of soluble sugar(SS) accumulated,which DRI was 119.24%～223.10%to the 28th day of stess. Malondiadehyde(MDA) accumulated than control in 10.62%～129.02%with the osmotic stess,reflecting the materials injured in varying degrees.4.During the early period of drought stess,growth rate under drought treatment raised slightly than under control,and then decreased with the degree of drought(range of increase 25.56%～87.41%).Wilted leaves under treatment were were 5～17 more than control by the difference of materials.5.Leaf area appeared different trends,its increase extent was 57.53%compared with control in SAG204081 and decrease extent was 25%in SAG204158 meanwhile.Tillering due to a number of different materials in responsed to different drought,drought treatment increased SAG 205171 maximum tillering,more than CK22.22 percent,but also by the stress of materials and decreased,tillering of E.nutans Gannan drop of 46.15%.6.All the material reducing the angle to reduce leaf transpiration,the largest decline in SAG 205172 down to 58.39%.Most of the material shortened the growing period to avoid drought stress,and SAG205171 jointing in the number of days to flowering 15 days earlier than the CK more obvious than orthers.Biomass increased 1.23%～33.73%when droughted,drought resistance materials affected by the relative small part of the ground fresh weight and dry weight were inhibited SAG 204059 minimum,only lower than 0.23 percent of its CK and 19.3%.7.Based on the grey correlative degree analysis,germination index and drought response index could be optimized as primary indicators;and germination rate,radicle length of 96 hours,radicle length,POD activity,height of plant,leaf area,days of sowing to anthesis,amount of stems,fresh weight of stems and leaves which correlated prominecely with the primary indicators could be optimized as the sub-indicators.8.According the order of comprehensive evalus,SAG204059 in germination and SAG 205190,SAG204059,E.sibiricus cv Chuancao No.2,SAG 205164 in the seeding to flowering stage of growth were much tolerant to drougt.Comprehensive evaluation showed that SAG204059,SAG205190,SAG205118was much tolerant to drougt in different development stages and could be used as important breeding materials in further study.