| 23 Arrhenatherum elatius L. germplasm materials were collected from overseas anddesigned to have different salinity levels (0, 0.35％, 0.45％, 0.55％,0.65％and 0.85％NaCl) and performances of the materials were evaluated in terms of survival rate, plantheight,tiller number, plant weight,plasmalemma permeability,concentration of free praline andMDA, activity of CAT, accumulation of Na+/K+ and photosynthesis rate. Based on theirperformances under the salt stresses, materials with high salt tolerance were screenedusing a comprehensive evaluation method. Finally, the genetic diversity among 23materials was analyzed by mens of ISSR marker.Main result obtained are as follows:(1)All germplasm materials can survival under the NaCl concentration <=0.45％; at0.55%—0.65％NaCl,the survival rates, relative height, relative tiller, growth stress indexand plasmalemma permeability began to decline;at 0.8-5％NaCl, majority materials weredead,it shows that the ability of salt tolerance of Arrhenatherum elatius L. in this researchis middling.23 Arrhenatherum elatius L. germplasm materials was divided into fivegroups according to TOPSIS-PCA analysis, ZXY03P-367 is the 1st group that scored0.9211; ZXY03P-165,ZXY03P-200,ZXY03P-269,ZXY03P-95,ZXY03P-238,ZXY03P-184,ZXY03P-387,ZXY03P-462,ZXY03P-319,ZXY03P-148,ZXY03P-416are the 2nd group that scored in 0.8—0.9; ZXY03P-79,ZXY03P-60,ZXY03P-337,ZXY03P-133,ZXY04P-949,ZXY03P-31 are the 3rd group that scored in 0.7—0.8;ZXY04P-991,ZXY03P-13,ZXY03P-133 was the 4th group that scored in 0.6—0.7;ZXY03P-45,ZXY03P-443 are last group that scored under 0.6.(2)Under salt stress, the osmoregulation system, membrane system andphotosynthetic system of Arrhenatherum elatius L. were damaged. The materials ofstrong salt-tolerance have high levels of proline content, sugar content, K+/Na+ content,MDA content,CAT acitivy and photosynthesis rate etc..Accroding to PCA,osmoregulation system is the most important factor that resistance salt stress, secondly ismembrane system and photosynthetic system. Cluster analysis show that: proline content,sugar content, K+/Na+ content, MDA content, relative water content, CAT acitivy,photosynthesis rate and chlorophyll content can be indexs to comprehensive evaluate theability of salt-tolerance for Arrhenatherum elatius L..(3) An optimized PCR reaction system for ISSR analysis was established:PCR was performed in a 20μl reaction mixture with 5μmol/L DNA, 2.5mmol/L Mg2+, 0.3mmol/Lof each dNTP, 300nmol/L primer, 1U Taq polymerase and 1×Buffer. Using 9 ISSRprimers,the genetic diversity among 23 Arrhenatherum elatius L. germplasm materialswere tested.A total of 88 bands were amplified by 9 ISSR primers,among which 66(75％)bands were found to be polymorphic.The ISSR-based genetic similarity values among 23materials accessions ranged from 0.591—0.886.Abundant genetic diversity amongArrhenatherum elatius L. accessions could be revealed by ISSR marker.Based on thecluster analysis and PCA,the 23 germplasm materials investigated may be divided intotwo groups,most of genetic variation was within group.There was a certain relationshipbetween genetic distance and geographic distance among Arrhenatherum elatius L. in theresearch.
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