| Chrysanthemum morifolium Ramat.belonging to the Compositae is a kind of perennial perennial root herb and can be used in medicine,is also a famous tea chrysanthemum,originating in Tongxiang City,Zhejiang Province.Chrysanthemum aphid is its main pest and disease,including Macrosiphoniella sanborni Gillette,Aphis gossypii Glover and Myzus persicae Sulzer,which can reduce the yield and decline the quality.The common chemical methods can also cause a variety of environmental problems.Breeding of aphid-resistant chrysanthemum varieties is an economical and effective way to control the disease.The purpose of this study was to determine the resistance to aphids of two main cultivars of hangbaiju chrysanthemum,Zaoxiaoyangju and Wanxiaoyangju,to explore its excellent germplasm and to investigate the mechanism of aphid resistance.The main results were as follows:(1)In the greenhouse,30 pots of 60 days old plants of Zaoxiaoyangju(ZT)and Wanxiaoyangju(WT)were respectively placed to form a rectangle with a spacing of 5 m.Each plant received 5 aphids and the plant morphology and color were measured.So find:① The number of aphids and the multiplication rate of aphids in ZT were significantly higher than that of WT(P<0.05).② Leaf length to width ratio,upper epidermis L*,a*,b*were positively correlated with aphids(P<0.01),and leaf aspect ratio,upper epidermis L*,a*,b*and C were significantly higher than those of WT(P<0.05)③ L*a*b*color three-dimensional map reveals that the color of the epidermis and the lower epidermis of the two species are significantly different.It is considered that the one with narrow leaf shape,yellowish green leaf color and brighter leaf color,which is preferred by Macrosiphoniella sanborni Gillette.(2)Aphid feeding behavior to two cultivars was analyzed via EPG(electrical penetration graph)responses to identified major chemical compounds in apex foliage of chrysanthemum plants.① The means of El and E2 duration,as well as those of total probing times of Macrosiphoniella sanborni on TW were relatively shorter,but significantly more in probing frequencies than those to TZ.A cluster analysis was completed using means of duration in waveforms of E1,E2,C,G,Pd and Np,as well as that of probing times as variables.② The results indicated that significant differences in resistance existed between the two chrysanthemum cultivars to their aphids.Significantly more soluble sugar and protein were found in apex foliage of cultivar TZ than those in cultivar TW.In contrast,phenols in cultivar TZ were less than those in cultivar TW.The amounts of soluble sugar and protein were correlated positively with E1 and E2 duration.But a negative correlation was shown relative to E2 duration.③ This may suggest that resistance of cultivar TZ against Chrysanthemum aphids was slightly weaker than that to cultivar TW,and phenols may be used as an index measuring their resistance.(3)Eight physiological and biochemical indexes of chrysanthemum leaves were determined under aphid injury,MeJA and SA treatments.① The activities of CAT,LOX,POD and the contents of soluble sugar,soluble protein,total flavonoids and total phenol were significantly increased by aphid injury.② Under the spraying of MeJA and SA,the activity of four defensive enzymes and the content of total phenol increased and varied with the induction time,while the flavonoids content of leaves decreased.③ The change rate of 8 physiological and biochemical indexes of Hangbaiju chrysanthemum under three treatments was analyzed by principal component analysis.The anti-insect characteristic material of Hangbai chrysanthemum may be CAT.The comprehensive score of insect resistance of two varieties of Hangbaiju chrysanthemum was WT(2.30)>ZT(-2.30)).(4)Aphid damage,MeJA and SA treatment can positively regulate cmwrky21,cmwrky40,cmwrky42,cmwrky48 transcription.① Under the feeding of aphid,the relative expression of cmwrky40 was about 80 times higher than that of ZT(P<0.05).Under the action of MeJA,the relative expression of cmwrky48 was nearly 70 times.With the influence of SA,the relative expression of cmwrky42 was approximately 20 times.② The grey correlation degree of cmwrky gene expression in three treatments showed that the relevancy between aphid damage and SA treatment was more nearly than that of MeJA treatment.It was concluded that the four wrky genes were related to the resistance of chrysanthemum,and the transcription level of cmwrky gene by aphid injury was closer to SA pathway.From the orientation behavior of aphids,it was found that its partial eosinophilic leaf shape was long and its leaf color was bright yellow and green.As per the sucking behavior detected by EPG and its associated leaves,the aphids absorbed soluble sugar,higher soluble protein content and total phenolic content.Lower early chrysanthemum.Damage and application of MeJA and SA induced defensive-related enzymes activity upregulation.This study can be referred to as a reference for the study of chrysanthemum resistance to insects. |
PDF Full Text Request