Study Of Copper-inducible Elicitor (CIE) Inducing Resistance To Verticillium Wilt Of Cotton

Cotton (Gossypium hirsutum) is China's important economic crops in the national economy. It is not only an important raw material in medicine, food, textile, chemical engineering, and national defense industries, but also an important export commodity. Verticillium wilt of cotton is one of the most severe plant diseases. Because it's hard to prevent and cure the Verticillium wilt of cotton, so the focus on the pathogen has been diverted to the host's resistance itself. This research was mainly about the effects of inorganic copper reagent which was a kind of non-biological elicitor on induced resistance to Verticillium wilt of cotton and the biochemical mechanism. The mechanism was illuminated in two aspects using Xinluzao-17 as the material. One was the effects on the resistance related enzyme, and the other was the effects on the secondary metabolic products. The experimental results were showed as follows. (1)With CIE sprayed on the cotton, the incidence and the disease index were 20.14%, 15.69 respectively. The incidence and the disease index of control group, which were higher than that of CIE-treated group, were 27.00% and 18.76. The results indicated that the CIE treatment took effect and reduced the incidence of Verticillium wilt of cotton and the disease index. (2)The activity of peroxidase in the third true leaf increased rapidly on the 1–3th day after the CIE treatment, and reached the maximum on the 3th day. It began to decrease on the 4th day, and it was close to the control level on the 6th day. The activity of polyphenol oxidase was higher than that of the control on 1–6th day after the CIE treatment. The activity of polyphenol oxidase rapidly increased on the 1th day. After a slight drop on the 4th day, it started to slowly rise, and began to decline on the 6th day. It was close to the level of the control on the 7th day. The results showed that CIE enhanced the activity of peroxidase and polyphenol oxidase. (3)The optimal extraction conditions for condensed tannin and total phenols were determined by single factor and orthogonal tests. The optimized extraction condition for condensed tannin was that the material-liquid ratio was 1:20(g/mL), the ethanol concentration was 40%(V/V), and the ultrasonic time was 30 min. The optimized extraction condition for total phenols was showed as follows, solid-liquid ratio of 1:60(g/mL), ethanol concentration of 40%(V/V), ultrasonic treatment time of 25 min. (4)The condensed tannin, total phenols and flavonoid in different tissues of different groups were studied. The results indicated that these secondary metabolic products were induced to increase by CIE treatment or the invasion of pathogen. The results also showed that the contents of these natural plant products changed in different growing period.