Effects of different kinds of rootstocks on economic yields and mineral nutrition contents of leaves of grafted watermelon seedlings

Effects of different rootstocks on grafting survival rates, economic yields and changing trends of 9 nutrient element contents of leaves of grafted watermelon seedlings were studied by using Xinong NO.8(X) watermelon seedlings as the scion, and C. maxima Duch(Q), Cucurbita moschata Duch(R) and Lagenaria siceraia(G) as the rootstocks. The results show that grafting survival rate and yield of G-X are significantly higher than those of R-X and Q-X, respectively. The contents of N, K, Ca and Mg of grafted watermelon leaves are remarkably enhanced by these rootstocks, especially at the reproductive growth stage. In addition, Lagenaria siceraia rootstock could cause a significant increase of Cu, Zn and Mn contents of grafted watermelon leaves compared with watermelon seedlings. At the vegetative growth stage N and Zn contents of Q-X，and Cu and Zn contents of R-X are significantly lower than those of the control, while Cu, Mn contents of Q-X, and Mn content of R-X are lower at the reproductive growth stage. Correlation analysis indicates that the correlations between the 9 element contents vary with different growth stages. These results show that the reason for the highest yields of the G-X is that the nutrient element contents of leaves are remarkably enhanced.