Morphological And Volatiles Of Spring Rape Resistance To Phyllotreta Humilis Weise In Inner Mongolia

Phyllotreta humilis Weise is a serious pest of seedling stage in spring rape in Inner Mongolia.The pest bite leaves and growth points of spring rape.And it causes the reduction of yield.Two insect-resistant varieties(Dahuang rape and Space mengIV)and one susceptible variety(Qingyou14)were choose to study in this paper,based on the previous studies.The content of leaf wax and water were measured.Pubescence density and pubescence length were gauged at three seedling stage of rape.In addition,there was difference of leaf colour between Space mengIV and Qingyou 14significently,the experiments of P.humilis to different leaf colour were carried out.Gas chromatography-mass spectrometry(GC-MS)was applied to analyze and identify the volatile components in three tested rape leaves.The results of the study are as follows:1.The contents of waterwere determined in seedling stage of three rapes.In the cotyledon stage,the second stage and the third stage of rape:the water content of Qingyou 14 was 89.48%,88.81%,88.29%,respectively.The water content of Dahuang rape was 91.35%,90.02%,and 88.19%,and the water content of space meng IV was 92.20%,91.13%,and 88.11%.The water content of rape in three stages were as follows:Space meng IV>Danghuang rape>Qingyou 14,and there were difference significantly.The results showed that P.humilis tended to the rape of low in water content.2.The wax contents of three rapes were measured.In the three stages of rape,the wax content of Dahuang rape was 0.3991%,0.7960%,1.3252%,and that of Space meng IV was 0.3728%,0.5778%,1.1699%,and that of Qingyou 14 was:0.3656%,0.5520%,1.0872%.In general,the wax contents of Dahuang rape were significantly higher than that of Space meng IV and Qingyou 14.The wax content of Brassica juncea L.was higher than that of Brassica napus L.,and higher wax content of rapeseed leaves with strong insect resistance.3.The results of pubescence length showed:the pubescence length was 252.63?m of front and 252.58?m of back of Dahuang rape,and 240.46?m of front and 246.00?m of back of the Space meng IV,and 248.49?m of front and 247.80?m of back of the Qingyou 14 in the second stages.There was no difference of pubescence length significantly among three varieties.In the third stage,the pubescence length of Space meng IV was 217.93?m of front and 176.82?m of back,and 288.74?m of front,289.66?m on back of Dahuang rape,and 276.90?m of front,and 260.89?m of back of Qingyou 14.In general,P.humilis tended to the rape with long pubescence length.4.Pubescence density of leaf was measured.Pubescence density was 7.91roots/mm~2 of front,7.88 roots/mm~2 of back of the Dahuang rape,0.97 roots/mm~2of front,1.24 roots/mm~2of back of the Space meng IV,and 5.00 roots/mm~2of front,5.26roots/mm~2of back of the Qingyou 14 at the second stage.At the third stage,the pubescence density was 2.79 roots/mm~2 of front,2.98 roots/mm~2 of back of the Dahuang rape,and 0.32 roots/mm~2of front,0.27 roots/mm~2of back of the Space meng IV,2.44 roots/mm~2 of front,and 2.43 roots/mm~2 of back of the Qingyou 14.Pubescence density was represented by Dahuang rape>Qingyou 14>Space meng IV in two stage,and there was differences significantly among three rape varieties.P.humilis tended to the rape with more pubescence.5.The time of P.humilis stayed on the filter paper was shorter significantly than that on the leaves of the Space meng IV and Qingyou 14.P.humilis stayed 9.41seconds on leaf of Space meng IV,and 16.36seconds on Qingyou 14.There was difference significently.The results showed that P.humilis tended to deep green leaf.6.The results of determination of volatiles in three spring rapes were as follows:There were 50 volatile substances in Dahuang rape,and the most important volatile substance is Allyl Isothiocyanate,and the relative content is 62.40%.There are six kinds of substances which relative content is greater than 1%,and the order of their contents from high to low is:Allyl Isothiocyanate,Butane,1-isothiocyanato,Benzene,2-isothiocyanatoethyl,2-Hexenal,1-Butene,4-isothiocyanato,Styrene.Qingyou 14 contains 46 volatile substances,of which the most important volatile substance is Allyl Isothiocyanate,its relative content is 70.91%,and its relative content is more than 1%,and there are 6 species,roughly related to the Dahuang rape volatile species.The same and similar in content.Space meng IV contains 55 kinds of volatile substances,of which the most important volatile substance is 2-Hexenal,and its relative content is 30.69%.There are 16 species in which the relative content is greater than 1%.The contents of the species were significantly different from those of Dahuang rape and Qingyou 14 varieties.Allyl Isothiocyanate may be the main volatile substance that attracts P.humilis.