| Lycium ruthenium is a small deciduous shrub in Solanaceae.It is mainly distributed in Qinghai,Ningxia,Gansu and other places in China.It is well known for its rich nutrients,high ecological value,economic value and medicinal value.In this study,water stress conditions were simulated with PEG(6000)solution at different concentrations to study the germination drought resistance of 17 different types of Lycium ruthenium ISSR-PCR reaction system was optimized and its genetic diversity was analyzed.Rapid tissue propagation system was established through primary generation,subculture and rooting culture in order to provide reference for the study of Lycium ruthenium germplasm resources and to protect them.Protecting vegetation in arid areas and cultivating desert plant resources provide valuable information,and contribute to solving agricultural and environmental problems in China and even in the world.The main results are as follows:(1)The results showed that the 20%PEG could inhibit the germination rate,germination potential,vigor index,germination index,relative root length and drought resistance index of 17 species.The 15%PEG centered;the 10%PEG was less inhibited,and each indicator decreased significantly with the increase of water stress(p<0.05).The ratio of the radicle/hypocotyl was increased under three different degrees of stress.which was 20%PEG>15%PEG>10%PEG>CK.(2)Drought-resistant subordinate function value method is adopted for comprehensive evaluation of the above seven indexes of drought resistance,the results showed that No.2,No.5 were drought-resistant varieties;while No.6 were moderate drought-resistant varieties;variety No.16,No.15,No.10,No.11,No.2,No.7,No.3,No.14,No.3,No.7 and No.9 were weak drought-resistant varieties.(3)The optimum medium for the first generation,callus,adventitious bud and rooting of Lycium barbarum L.was WPM medium without any exogenous hormones,X5:6-BA 2.0 mg/L+NAA 0.05 mg/L,Y5:6-BA 1.5 mg/L+NAA 0.1 mg/L and Z4:IBA 0.5 mg/L.The emergence rate,callus rate,induction rate and rooting rate were 100.0%,100.0%,530.0%and 100.0%.(4)Combining single factor and multi-factor comprehensive experiments,the 25-mu-L reaction system of ISSR-PCR amplification of Lycium barbarum L.was finally determined as follows:3.0U Taq DNA polymerase,50ng template DNA,2.4 mmol/L Mg2+,0.240 mmol/L DNTPs,and 0.4 micromol/L primer.(5)Eleven primers were screened from 30 ISSR primers randomly selected to analyze the polymorphism of 14 Lycium barbarum.A total of 119 distinct bands were amplified,of which 112 were polymorphic bands with a polymorphic ratio of 94.12%.The primers with the largest number of bands were 879 and 813,respectively.The number of bands amplified by the two primers was 16 and 7,respectively.The genetic distance and cluster analysis of 14 Lycium barbarum cultivars showed that their genetic distance ranged from 0.1500 to 0.9310,with an average genetic coefficient of 0.5020.At the threshold of 0.57,they were divided into three groups,and at the threshold of 0.47,they were divided into five groups. |
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