The Effects Of Extracts Of Plant On Tobacco Mosaic Virus And Their Mechanism To Control Disease

Pots experiments were conducted to study the effects of extracts from different plant (Basella rural L.shorted for L,Bougainvillea spectabilis Willd shorted for M and Phytolacca americana shorted for S) and inhibitor on tobacco mosaic virus and their mechanism to control disease,by inoculating TMV on healthy tobacco,which in 2004 ～2005 in Henan Agricultural University. The host plant were Nicotiana tobacum cv K326 and N.glutinosa L. The following results were obtained through analysizing or measuring the changes of physiologic and biochemical indexes(including the activity of protectingenzyme such as superoxide dismutase(SOD), peroxidase(POD), catalase(CAT) and Polyp -henol oxidase(PPO), C, N metabolism and lipid peroxidation levels ), photosynthetic character, fluorescent induction kinetics parameters, vitality of root system, inhibitory effect and the quantity of flue-cured tobacco leaf..1. The extracts of plant and inhibitor could scavenge the superoxide radical and hydroxyl radical significantly. there is different effect in different scavenging system, the pure extracts has the best scavenge effect on superoxide radical and hydroxyl radical than any other scavenging system, the effect of after being treated to the tobacco was poor to the pure extract system, healthy leaf system and diseased leaf system obviously, the integrated effect on scavenging superoxide radical all of the agents were that: Z>S>L> M; and scavenging hydroxyl radical were: Z>L>M>S. enzyme such as superoxide dismutase(SOD), peroxidase(POD), catalase(CAT) and Polyp -henol oxidase(PPO),C,N metabolism and lipid peroxidation levels),photosynthetic character,fluorescent induction kinetics parameters,vitality of root system,inhibitory effect and the quantity of flue-cured tobacco leaf..1. The extracts of plant and inhibitor could scavenge the superoxide radical and hydroxyl radical significantly, there is different effect in different scavenging system, the pure extracts has the best scavenge effect on superoxide radical and hydroxyl radical than any other scavenging system, the effect of after being treated to the tobacco was poor to the pure extract system, healthy leaf system and diseased leaf system obviously. the integrated effect on scavenging superoxide radical all of the agents were that: Z＞S＞L＞M; and scavenging hydroxyl radical were: Z＞L＞M＞S.2. After being treated by different extracts and inhibitor,the protecting enzymes activities in leaves infected with TMV were all increased in some content, lipid peroxidation levels were decreased and the content of total phenolics compounds was increased obviously; compared with the healthy plant, the physiologic and biochemical indexes in leaves induced by extracts and inhibitor were nearly or reached to it; Finally, which promote the plant growth, and strength the anti-mosaic activity, as far as measure is concerned, using extracts and inhibitor before inoculation has better effect, the integrated effect all of the agents were that: Z＞S＞L＞M.3. After treated by the extracts and inhibitor,the net photosynthetic rate(Pn),transpiration rate (Tr),stomatal conductance(Gs) and intercellular CO₂ concentration(Ci) in leaf were nearly or reached to healthy plant greatly, as far as the measure using extracts and inhibitor before inoculation is concerned, after treatment for 12d, the net photosynthetic rate in leaf treated by L,M,S and Z, which were 95.07％,92.22％,94.90％and 98.33％compared to healthy plant respectively; the content of chlorophyll has been increased significantly; the biggest efficiency of photochemistry of PSII(Fv/Fo) and potential activation of PSII(Fv/Fm) were all increased, and strengthened conversion of light energy, promoted the photosynthetic character. the integrated effect all of the agents were that: Z＞L＞S＞M.4. The extracts and inhibitor could increase the vitality of root system obviously; and strengthen the activity of NR and IvR. The effect of Z treatment was best during all of the treatment, and the activity of NR and IvR were reached to 107％and 104％compared to the healthy plant respectively.5. The result based on routine PAGE showed that, There ere new Pathogenesis-related proteins(PR) in the leaves treated with extracts and inhibitor. On the third day after treatment, there is a special PR about 15.9 KDa induced with inhibitor; and there are three pieces of PR about 49.1KDa,54.1 KDa and 16.9 KDa induced on sixth day,twelfth day and twenty-forth day after treatment, respectively; There are special PR about 27.5KDa and 26.9 KDa induced with Basella rural L. on third day after treatment.; and there are five special pieces of PR about 54.2KDa, 67.6 KDa, 84.5KDa, 88.3 KDa and 69.4KDa induced with Bougainvillea spectabilis Willd on sixth day,twelfth day and,fifteenth day and twenty-forth day respectively; and about Phytolacca Americana The special PR about 19.5 KDa was induced on fifteenth day after treatment.6. The extracts and inhibitor have significant effect in controlling Tobacco mosaic disease and inhibitory multiplication of TMV. And the defend effect is excelled to cured effect. the inhibitor has better effect than any single extract in in controlling Tobacco mosaic disease and inhibitory multiplication of TMV either before or after inoculation,the inhibitory effect was 82.3％and 77.3％respectively, and the inhibitory multiplication effect was 58.03％and 49.29％respectively, the integrated effect all of the agents were that: Z＞L＞S＞M.7. The chemistry ingredient in tobacco leaf showed that, the quality of leaf disposed by inhibitor was more harmonized and content was in reason, the usability of leaf is increased obviously.as far as the measure using extracts and inhibitor further inoculation is concerned, the content of K₂O,nicotine,total nitrogen,total sugar and deoxidize sugar were equivalent 103.4％,125.2％,136.01％,103.6％,102.2％and 97.2％to healthy plant respectively, and improved 21.1％,4.28％,5.18％,12.9％,25.4％and 18.8％to diseased plant respectively.As natured extracts and inhibitor, The effect on controlling tobacco mosaic disease including many aspects. Be the same as other vegetable inhibitor, the mechanism of controlling TMV manifest following aspects mainly: inactive virus, induce producing anti-disease activity,improve the resist-contradictorily of plant itself, and so on. The extracts and inhibitor are of the superiority to propagation that has innocuity and security, and has a promising application prospect in production.