Effects Of Bemisia Tabaci Damage On Tomato Quality, Growth And Development, Physiological And Biochemical Characteristics

In recent years, Bemisia tabaci(Gennadius) has become one of the most important pests of tomato, causing large economic losses due to decreasing yield and quality of tomato. The effects of Bemisia tabaci damage on tomato quality, growth and development, physiological and biochemical characteristics were studied in this paper to further understand the damage mechanism of Bemisia tabaci. The study will be a theory basis for Bemisia tabaci management and breeding of insect-resistant tomato. The major results are as follows:1,The effects of Bemisia tabaci damage on tomato qualityThe effects of Bemisia tabaci at different damage densities on tomato quality were studied in this paper. The results indicated that at mature stage as the density increased the contents of vitaminC(VC) and sugar decreased by 15.07%-54.49% and 9.75%-62.40%, respectively The ratio of solution sugar to acid also dropped significantly with the increasing damage degrees. However, total acid and proteins at green mature stage and mature stage didn't change with apparent law. Several nutritional statuses including Vc, total sugar, Suger/Acid, total acid and proteins were all lower at green mature stage than at mature stage The pollen vitality as well as the fruit-set rate was negatively affected by the damage degree. The pollen vitalities at 3, 4, 5 degree levels were 83.6%, 66.4%, 58.8% of the control, respectively, while the fruit-set rates ranged from 24.1% to 97.7% of the control at different damage degrees The mean weights per fruit were 92.2%-48.0% of the control2,The effects of Bemisia tabaci damage on tomato growth and developmentThe results showed that growth and development of tomato were significantly influenced when the damage densities were 50 and 450 individuals per plant. There were no obvious differences in plant height and stem girth at the first 7 days, while the differences became more and more significant from the 14th day after damage. After 28th day,the plant heights of the treatment of 50 individual per plant declined 19cm compared with the control; the plant heights of the treatment of 450 per plant declined 23cm compared with the control .The most sensitive character influenced by Bemisia tabaci damage was the dry weight which became 71.56% and 45.09% of the control on the 28th day after damage when densities were 50 and 450 individuals per plant, respectively. Seedling index of tomato on the 28th day after damage of 50 individuals per plant was 83.27% of the control,while the corresponding value was 37.98% at 450 individuals per plant. The trends in effects of Bemisia tabaci on RGR and SSI were similar The effects of Bemisia tabaci damage on RGR is wery significant.3,The effects of Bemisia tabaci damage on tomato photosynthesis, chlorophyll, root activity and plasm concentrationThe results showed that:(1) The damage of Bemisia tabaci effect the photosynthetic rates of tomato leaf.The photosynthetic rates of tomato leaf were 93.48%, 90.13%, 89.35% of the control at the 3rd, 6th, 9th day after damage respectively when the density was 50 individuals per plant, while the corresponding values were 86.23%, 81.57%, 78.70% at 450 individuals per plant.(2) The damage of Bemisia tabaci affect contents of the total chlorophyll. The contents of total chlorophyll ,chlorophyll a and chlorophyll b were significantly differents after Bemisia tabaci damage. The decrease rate of the total chlorophyll,chlorophyll a and chlorophyll b reached 24.60%, 25.24% and 23.55% respectively at 9 days after damage when the density was 50 individuals per plant, while the corresponding values were 49.13%, 62.02%, 23.55% at 450 individuals per plant.(3) The damage of Bemisia tabaci effect root activity. The damage density of Bemisia tabaci had a reverse effect on root activity,the values of which were 90.41%,87.80%, 78.02% of the control on the 3rd, 6th, 9th day after damage respectively when the density was 50 individuals per plant, while the corresponding values were 82.88%,77.91%, 60.78% at 450 individuals per plant.(4) There were significant differences in soluble sugar of tomato seeding compared with the control at 9th days after damage both with density of 50 individuals per plant and of 450 individuals per plant The proline contents of tomato seeding leaf were 1.74-times and 2.44-timescompared with the control at 9th days after damage when the densities were 50 and 450 individuals per plant, respectively.4,The effects of Bemisia tabaci damage on protective enzymes of tomato seedingThe effects of Bemisia tabaci damage on protective enzymes of tomato were complex. The POD activities of tomato leaf increased with the days after treat, the values of which were 108.58%, 128.29%,142.99% of the control on the 2nd,4th,6th day after damage respectively when the density was 50 individuals per plant,while the corresponding values were 130.66%, 163.94%,184.75% at 450 individuals per plant.The effects of Bemisia tabaci damage on PAL activity were similar with the effects on POD except that the ascending range of PAL activity was much smaller.The CAT activities of Bemisia tabaci damaged tomato were always higher than that of the control. The activity of 50 individuals per plant reached the peak on the 4th day after damage,and decreased from the 6th day..In the same time,CAT activities is 116.54%,132.84%,118.06% respectively of the control. The activity of 450 individuals per plant reached the peak on the 2th day.In the same time ,CAT activities is 129.43%,112.5%,101.4% respectively of the control.The PPO activities of tomato seeding leaf increased with the days after treat,.After 4th days of damage,SOD activities of the treatments of 50 and 450 per plant is significantly highter than the control.