| Annual ryegrass(Lolium multiflorum)is a worldwide-cultivated cool-season annual high-qulity forage grass,which is an application important forage grass for the southern artificial grassland,grazing land and mowing land in china.With the areas of saline soil increasing,investgatation of how to use the saline soil effectively has become a significant topic.So validing the salt tolerance annual ryegrass is very necessary.The object of this study was to systemicaly evaluate the salt tolerance of annual ryegrass,which could provide a basic materials for the breeding of new ryegrass variety and could help understanding the mechanism of ryegrass salt tolerance.The results were as follows:1.Effects of four different sodium salt stress on seeds germination of annualryegrassSalt tolerance of 6 different annual ryegrass cultivars during seeds germination process was studied by measuring the germination energy,germination rate,germination index,vigor index and root length/germ height under treatments of sodium carbonate,sodiumbicarbonate,sodiumsulfate and sodiumchloride.The results showed that the germination energy,germination rate,germination index,vigor index and root length/germ height decreased with the increasing of salt concentration.The standard deviation coefficient allocation weighted methods were used to evaluate the salt tolerance of the cultivars comprehensively.The results indicated that the most tolerant variety to sodiumsulfate stress was R102-3 which have a D value of 0.281;the most tolerant variety to sodium carbonate stress was Aubadewhich D value was 0.150;the most tolerant variety to sodiumbicarbonate stress was "Changjiang No.2"which D value was 0.313;the most tolerant variety to sodiumchloride stress was"R102-3”which D value was 0.458.2.Analysis of seedling salt resistance of annual ryegrassEight physiological index of two different annual ryegrass varities were measured to analyze the salt resistance of annual ryegrass,the results indicated that the RWC decreased with the increase of treatment time,while the instead of EL?MDA.Soluble sugar?Pro?POD and SOD were increased.But the concent of CAT increased firstly and then decreased.The conclusion was that,"R102-3" was more tolerance than "Tetragold" when Coinside with the relationship between the physiological index and salt resistance.3.Identification of the valid reference genes in annual ryegrass under salt stressqRT-PCR was used to evaluate the suitable reference genes form seven housekeeping genes(eEFlA(s),GAPDH,EFl-a,eIF-5A,YT521-B,TBP-land Actin)in annual ryegrass under high concentration of salt.The results calculated by RefFinder revealed that eEF1A(s)was the most stable reference gene and the stability value was 1.41,and the next was GAPDH,which value is 1.86;meanwhile the EF1-a(6.24)was the least stable one.So the eEFlA(s)and GAPDH were the suitable reference genes were suggested for salt resistance study of annual ryegrass.4.Analysis of antioxidant genes expression during germination of annual ryegrassFor ensure the accurate of qRT-PCR,we chose the most stably reference genes(eEF1A(s)and GAPDH)to normalize the antioxidant genes expression data.The results which calculated by 2-??Ct indicated that relative expression of Fe-SOD,Mn-SOD,Chl-Cu/Zn SOD,Cyt-Cu/Zn SOD,POD and CAT were increased firstly and then declined with the increased of treatment time.Mean while,"R102-3" had higher expression of the studied genes when compared with "Tetragold",which indicated that "R102-3" was more tolerance than "Tetragold" under salt stress.Overall,R102-3 have a higher salt tolerance than "Tetragold" in germination and seedling of annual ryegrass.Which could lay the foundation of evaluating and identifying the salt tolerance annual ryerass varies and would be beneficical for taking effective measures to change or to rationally use the saline soil. |
PDF Full Text Request