Effects of Grafting on Sugar Metabolism of Melon (Cucumis melo L.) Seedling under Copper Stress

Abstract The experiment was carried out with pumpkin ‘JingXinZhen NO.3’ as the rootstock, thin-skin melon ‘IVF09’ as the scion, and self-rooted seedling as the control. The effect of grafting on the sugar metabolism of melon seedlings under copper stress was studied. The results showed that under the condition of copper stress, the growth of melon seedlings was inhibited, the sugar content of leaves decreased, and the sucrose content decreased significantly, and the total activity of sugar metabolism related enzymes changed. However, under the same conditions, the biomass of the grafted seedlings is greater than that of the self-rooted seedlings, and the greater the stress concentration, the greater the grafting promoting effect; Glucose and fructose in grafted leaves were significantly higher than those in self-rooted seedlings, raffinose and stachyose were significantly lower than self-rooted seedlings, the highest ratio of glucose to fructose increased by 5.26% and 32%; and the total activity of sucrose synthase (SS) in the leaves of grafted seedlings was lower than that of self-rooted seedlings. The total activity of sucrose phosphate synthase (SPS), neutral invertase (NI) and acid invertase (AI) was greater than that of self-rooted seedlings. The results showed that grafting could change the sugar activity of seedling leaves by changing the total activity of sugar metabolism related enzymes in melon seedling leaves, and then change the sugar metabolism of melon seedlings to reduce the toxicity of copper stress on melon seedlings.