| Tea green leafhopper, Empoasca vitis G?the, is the worst damaged pests in tea plantations in the mainland tea growing area in China. During the field practice, the phenomena that the various tea plant cultivars suffer from the leafhopper at different degree usually occurs, on which the investigation was scarce. exactly. The secondary metabolites in tea plants was one of material basis against pests. However, the resistance of the various metabolites against the leafhopper was rare to report. The video direct current electrical penetration graphy (DC-EPG) was used to detect the leafhopper feeding behaviour on the six elite cultivars which have been grown in the southern Jiangsu Province and Zhejiang Province. In succession, we supplied the leafhopper feeding with nine types of the secondary metabolites, so as to detect their influencing the feeding behaviour of the leafhopper. The results as follows:1. On the basis of the feeding behaviour of the leafhopper on the six elite cultivars, the results showed that: (1) The seven primary types of waves from the leafhopper feeding were the same on each cultivar, i. e. non-feeding wave NP, probing wave A, saliva excreting wave S, actively feeding wave C before stylets reach phloem, passively feeding wave E in phloem, obstructive wave F while stylets were obstructed out of cell membrance or within cell wall, as well as rest wave R. (2) The number of probing times were few and the durations of E wave were long on the Xicha 5 and Sucha 1; contrarily, the number of probing times were more and the durations of E wave were short on Longjing 43. The number of probing times and the durations of E wave were intermediate on Sucha 120, Zhongcha 108 and Anjibaicha. (3) Generally, the probing times were few and the durations of E wave were long on the sensitive cultivars. Then by means of cluster analysis and multiple range test, the resistance of six cultivars against the leafhopper the from strong to weak ranked in turn: Longjing 43 > Sucha 120 > Zhongcha 108 > Anjibaicha > Sucha 1 > Xicha 5. The rank was consistent with the order of the population density of the leafhopper from little to large on the six cultivars observed for many years.2. The feeding behaviour of the leafhopper on the nine types of the secondary metabolites were recorded by DC-EPG. The following waves were obviously observed: E wave, np wave, A wave and S wave. E wave, np wave and path wave (A+S) as indices, the nine types of substances were divided into 3 types by cluster analysis. Based on the durations of E and np again, we thought theaflavin could promote the feeding of tea green leafhopper, the theanine, Chlorogenic acid, glutamic acid Epicatechin gallate, Epigallocatechin and Epigallocatechin gallate were all inhibitor, but there was little effect on tea green leafhopper of tea polyphenol and catechin.Comparing with the 5% surose, the theaflavin could promote the feeding of tea green leafhopper, while the concentration of theaflavin was 0.05%; the theanine, glutamic acid, Chlorogenic acid, Epigallocatechin, Epigallocatechin gallate and Epicatechin gallate were strong ingestion and penetrationn deterrent to leafhopper, while concentration of the Chlorogenic acid, Epigallocatechin gallate and glutamic acid was 0.15%, theanine, Epicatechin gallate and Epigallocatechin was 0.10%. On all accounts, DC-EPG techniques can be used to quickly judge the resistance of the different cultivars against the leafhopper, and act as assistant means of the resistance detecting. The techniques can be still used to compare the fitting degree of the secondary metabolites to gestation by the leafhopper. The quality and the quantity of the secondary metabolites differ in the various cultivars obviously, which are beneficial to explain the resistance or the sensibility of the different cultivars to the leafhopper.
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