The Relationship Of Nutrient Materials And Volatile Materials On Aphid-resistance Of Cucumber

Aphid(Aphis gossypii glover) is a serious pest to cucumber in the world. Chemical defence is a main measure to control aphids, which causes environmental pollution and increases the resistance of aphids to pesticide. Plant resistance is one of the economic and effective way to defence the aphids. However, there are few studies on insect-resistant materials and its mechanism is unknown until now. Glabrous cucumber is the mutant of normal cucumber. We found that the mutant had the ability of aphid-resistance. We chose glabrous and normal cucumber as materials, using nets to prevent aphids infection. We bred aphids three generations and inoculated them on the glabrous and normal cucumber leaves. First we tested for selective resistance appraisal. Then nutrient and volatile compounds were researched to evaluate the resistance mechanism of glabrous cucumber. The results were as follows:1.Selected test of glabrous and normal cucumber indicated that aphids were prefer normal cucumber leaves to glabrous cucumber. After inoculated sixteen hours,the glabrous cucumber avoided aphids obviously. Twenty-four hours later, it showed much obviously. In conditions of artificial inoculation, there were different number of aphids on glabrous and normal cucumber plant. Aphid number all increased. Aphids on glabrous cucumber increased in a low speed,there were one hundred of aphids on cucumber until 8 days later. However, aphids on normal cucumber increased in a high speed, the number of aphids was two times more than glabrous by eight days, the glabrous cucumber showed aphid resistant characteristics.2.Chose glabrous and normal cucumber uninoculated and inoculated eight days, the contents of soluble sugar, soluble protein, free amino acid and various amino acids were tested. The experiment results showed that the contents of soluble sugar, soluble protein and free amino acids in the glabrous cucumber leaves were lower compared with normal cucumber, the contents of nutrients were descended after aphid infection. Low nutrients were useful to resist aphids. High content of Leu, Ile, Pro, Val, Ser and low levels of glu, Ala, Lys, Asp, Arg might be disadvantage of aphid breeding.3.Compared with the normal cucumber, the uninoculated mutant contains specific volatile material of Ocimene. Inoculated glabrous cucumber increased beta.-Farnesene,d-Camphene and Cumarin, 6-(3-nitrobenzylidenamino)-. This kinds of terpenoids material would pay great role on plant - insect- natural enemy,which could get rid of aphids and atract their natural enemy. 4.Glabrous cucumber was a new germplasm resources which selected in this test, and it will provide the theoretical and practical basis of resistance breeding in the future.