不同中间砧对苹果果实苹果酸代谢关键酶活性及其相关基因表达的影响

为深入探究中间砧影响苹果果实苹果酸代谢的机理，以SH40实生后代（代号53、111和236）为中间砧嫁接的‘天红2号’苹果树为试材，测定果实发育过程中苹果酸含量、相关代谢酶活性及基因相对表达量。结果表明：果实成熟时，以53号为中间砧嫁接的‘天红2号’果实苹果酸含量显著高于以111号为中间砧的。盛花后30、40、100 ~ 160 d，以53号为中间砧的果实中苹果酸脱氢酶（NAD-MDH）活性显著高于以111号为中间砧的；盛花后30、40和130 d，53号处理的磷酸烯醇式丙酮酸羧化酶（PEPC）活性显著高于111号处理的；盛花后100 d，以111号为中间砧的果实中苹果酸酶（NADP-ME）活性显著高于以53号为中间砧的。基因表达结果显示，盛花后100和160 d，以53号为中间砧的NAD-MDH基因相对表达量显著高于以111号为中间砧的，同时NADP-ME基因表达量也显著高于以111号为中间砧的；盛花后30 和160 d，以53号为中间砧的PEPC基因相对表达量显著高于以111号为中间砧的。

Effects of Different Interstocks on Key Enzymes Activities and the Expression of Genes Related to Malic Acid Metabolism in Apple Fruit

In order to study the metabolism mechanism of malic aicd in apples on different interstocks，‘Red Fuji’apple trees grafted on three interstocks No.53，No.111 and No.236 were used as materials in this experiment，which were chosen from SH40 seedlings. The contents of malic acid，the enzymes activities and the expression of genes related to malic acid metabolism were analyzed during the fruit development. The results showed that the malic acid content in the ripe fruits on No.53 inter-stocks was higher than that of No.111. The NAD-MDH activities in Fuji apple on No.53 inter-stocks were higher than that of No.111 in the 30，40，100 and 160 day after full bloom，the PEPC activities in Fuji apple on No.53 inter-stocks were higher than that of No.111 in the 30 and 130 day after full bloom，and the NADP-ME activities in Fuji apple on No.111 inter-stocks was higher than that of No.53 in the 100 day after full bloom. The relative expression of NAD-MDH gene and NADP-ME gene in fruit on No.53 inter-stockswere higher than that of No.111 in the 100 day and 160 day after bloom. The relative expression of PEPC gene in fruit on No.53 inter-stock showed higher than that of No.111 in the 30 day and 160 day after full bloom. It was concluded that different interstocks influnced expression of genes related to malic acid synthesis and degradation firstly，then related enzymes activities would be regulated，and at last resulted in different malic acid contents in apple on different-inter stocks.