| Ramie is an excellent natural fiber crop in our country.With the rapid development of science and technology,the multi-functional use of ramie has been continuously developed,and its application value has also expanded and increased,its industry is developing in the direction of comprehensive utilization of fiber use,feed use,soil and water conservation,soil remediation,etc.direction of development.During the growth of ramie,it is easily infected by pathogenic bacteria and pests,resulting in a serious decline in the yield and quality of ramie fiber.In this study,by comparing the ability of different ramie varieties to resist mosaic disease and root rot nematode disease and the degree of self-recovery,the effect of disease stress on the main agronomic traits,yield and leaf physiological indicators,root morphology,root physiological and biochemical properties of different ramie varieties was explored.The impact of ramie disease provides a theoretical reference for further development of ramie disease prevention and control in the future.The main results are as follows:1.Through the resistance analysis of three varieties with different resistance to Mosaic disease after inoculation,the disease resistance of each variety is Xiangzhu No.3 > Bijie Yuanma > Dayong Huangkema.Xiangzhu No.3 showed symptoms last and has strong disease resistance,which is significantly better than other varieties.It was concluded that Xiangzhu No.3 was highly resistant variety,Bijie Yuan was susceptible variety and Dayong Huangkema was highly susceptible variety.2.After Ramie was infected by mosaic disease,the plant height,stem diameter,fresh skin thickness,fresh skin weight,biological yield and chlorophyll content of infected ramie were lower than those of healthy control.The content of chlorophyll fluctuated and increased when the infected plants were lower than the healthy ones,which indicated that there was a process from destruction to recovery of chloroplasts in a long time after infection.3.By measuring resistance of different ramie varieties in leaf blade after being Mosaic infect variation of the enzyme activity and gene expression analysis,quantitative results showed that the Polyphenol oxidase(PPO)activity,Peroxidase(POD)activity and Superoxide dismutase(SOD)activity in leaves increased rate was positively correlated with Mosaic resistance level.Phenylalanine ammonia-lyase(PAL)activity and MDA content increase rate and negatively correlated with Mosaic resistance level.Compared with Dayong Huangkema and Bijie Yuanma,Xiangzhu No.3 gene had shorter response time and higher expression abundance.4.Under the stress of root rot nematode disease,the root fresh weight of six resistant ramie cultivars decreased,and the higher the resistance of root nematode disease,the less the influence on the root fresh weight of,and Huazhu No.4 had the lowest reduction rate(23.76%).The ratio of root to shoot of ramie cultivars with different resistance was different,Compared with CK,Changsha Qingyema rate of decline the highest(75.79%),indicating that it was highly sensitive to root rot nematode stress.5.By measuring the changes in leaf enzyme activity,root enzyme activity and MDA content after different resistant ramie varieties were infected by root-rot nematodes,the results showed that POD activity and SOD activity in ramie leaves,ramie root antioxidant enzymes POD activity and CAT activity the rate of increase was positively correlated with the level of root rot nematode,and the rate of increase of MDA content was negatively correlated with the level of resistance to root root nematode disease.6.The study of root secondary metabolites and root sugar content found that the increase of total phenol content of disease resistant materials was much higher than that of susceptible materials.When expressed as the percentage of the increase after inoculation before inoculation,the increase of resistant varieties was 2-3 times higher than that of highly susceptible varieties;The increase and absolute content of lignin content and chlorogenic acid content in resistant varieties were higher than those in infected varieties;After inoculation with root rot nematode,the total sugar content of susceptible varieties increased and the content of resistant varieties decreased.7.The contents of amino acids in the root exudates of different ramie varieties infected by root rot nematode were determined by measuring their resistance,the results showed that in susceptible control roots the contents of methionine,histidine,L-Aspartic Acid,alanine,threonine,serine,glutamic acid and isoleucine were significantly higher than those in resistant varieties,the content of arginine in the roots of resistant ramie varieties was higher than that of resistant ramie varieties,the total contents of amino acids in the highly susceptible varieties Ningxiang Chongtianpao and Changsha Qingyema increased by 58.26%and 55.28%,while those in the resistant varieties increased by 16.53% and 13.56%,The total contents of amino acids in the highly susceptible varieties were 3-4 times as much as those in the resistant varieties. |
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