Changes Of Physiological And Biochemical Indexes And Pathological Observation Of Lily Under LSV Stress

Lily symptomless virus (LSV) is the leading virus causing lily bulb degradation which brings serious harm to lily planting. Eradicating the virus now has become a urgent task for the science worker. In this study, we first purified the lily symptomless virus (LSV) from susceptible lily plants. Then infected drug-free seedlings of Siberian and Sorbonne with the purified virus to study the change of host plant physiological and biochemical indexes after the LSV infection. Finally, susceptible host ultrastructure were studied by electron microscopy techniques. Its findings provide the basis for understanding the pathogenesis of LSV and disease resistance breeding of lily.We used secondary PEG precipitation and sucrose density gradient separation and purification method to purify LSV. Experimental results show that:complete and a large number of LSV could be obtained with the second method. Virus UV absorption peak is270nm, OD=1.714. The lowest absorption peak is240nm, OD=0.921.OD260/OD28o=1.323. The virus concentration is0.328mg/ml. Virus production is1.453mg/100g.We used the purified LSV to infect Siberian and Sorbonne, then determined lily chlorophyll content, photosynthetic rate, SOD, POD, PPO and PAL activity to clear the physiological and biochemical changes of lily which infected by virus. Experimental results show that:There is different degrees of reduction at chlorophyll a, chlorophyll b and total chlorophyll content of both LSV infected lily, which compared with the healthy control plants that Siberian are28.6%,33.3%and23.5%where Sorbonne are10%,12.5%and11.7%, respectively. Pn, Gs and Ci of the two susceptible lily also reducted comparing with healthy controls which Siberian are33.3%,25%and13.8%, respectively, Sorbonne are15.3%,18.5%and7.1%. Antioxidant enzyme system reacted regularly. SOD activity of both lilies increased significantly than healthy controls, increasing by23.3%and11.7%respectively. Siberia POD activity increased by29.4%, and the Sorbonne increased by10.3%. PPO activity grew by16.7%and9.2%at preseed stage. PAL activity grew by42.5%and26.6%respectively.The original normal metabolic system is disorder and secondary metabolic system enhanced.TEM observations of the ultrastructure of the host by LSV and LMoV display that in the LSV infected paints, almost all of the chloroplast lamella structure are stunted, osteoporosis and chloroplast lamella structure expansion. It become deformed.Most of the starch grains inflation and increased in the chloroplast.Other chloroplast outer membrane digestion. While in the LMoV infected paints, almost all of the chloroplast lamella structure are stunted, lamella structure is loose, messy, and chloroplasts deformed and partial chloroplast swelling round. In most of the chloroplast, the number of starch grains increased and some starch grains enlargement and occupy the entire chloroplast. Part of the chloroplast membrane local damage.Compared with normal control, the number of mitochondria is increased in two infected plants.