内蒙古农业大学学报(自然科学版)

为研究不同砧木对西瓜果实糖分积累的影响，本研究以‘美都’/野生西瓜砧（WGW）、‘美都’/南瓜砧（PGW）2种嫁接苗和‘美都’自根苗（SRW）为材料，测定果实发育期间糖分组成含量及蔗糖代谢相关酶活性变化。结果显示：(1)3种类型西瓜果实发育期间果糖、葡萄糖、蔗糖及总糖含量逐渐升高，至果实成熟总糖含量由高到低顺序依次为WGW、SRW、PGW；不同糖分组成占比也有所不同，SRW以葡萄糖占比最高（达43%）,PGW和WGW葡萄糖占比最低（分别为30%和28%）。(2)3种类型西瓜果实发育期间，蔗糖合成酶（SS）、蔗糖磷酸合成酶（SPS）、酸性转化酶（AI）和中性转化酶（NI）均维持一定活性，整体呈先上升后下降变化趋势，PGW与SRW和WGW相比，果实发育期间转化酶活性处于较高水平，蔗糖合成酶合成方向则处于较低水平。(3)3种类型西瓜果实糖分与代谢酶活性相关性表现有所不同，WGW蔗糖含量与SPS呈极显著正相关，与AI、NI分别呈显著、极显著负相关，SRW果糖和葡萄糖与蔗糖合成酶分解方向（SS-I）呈显著正相关。总之，不同砧木嫁接影响西瓜果实糖分积累，野生西瓜嫁接能提高果实总糖含量，但果糖含量占比有所下降，调节蔗糖代谢相关酶活性可能是不同砧木嫁接果实糖分积累差异形成的原因之一。

To study the effect of different rootstocks on the sugar accumulation of watermelon fruit, two grafted seedlings of 'Medu'/wild watermelon rootstock(WGW), 'Medu'/pumpkin rootstock(PGW) and 'Medu'/wild watermelon rootstock(WGW) were used as materials to determine the content of sugar composition and changes in the activities of enzymes involved in Suc metabolism during the fruit development. The results showed that: fructose, glucose, sucrose and total sugar contents of the three types of watermelon fruits gradually increased during the fruit development, and the total sugar contents of the three types of watermelon fruits were in the order of WGW>SRW>PGW until fruit ripening. The proportions of the different sugar compositions varied, with the glucose taking up the highest proportion of SRW, amounting to 43%, and the glucose accounting for the lowest proportions of PGW and WGW, amounting to 30% and 28%, respectively. During the development of the three types of watermelon fruits, sucrose synthase, sucrose phosphate synthase and converting enzyme maintained a certain level of activity, with an overall trend of first increasing and then decreasing, and the activity of the converting enzyme was at a higher level and the direction of the synthesis of sucrose synthase was at a lower level in the PGW as compared with the SRW and the WGW during the development of the fruits. The three types of watermelon fruit sugar and metabolizing enzyme activity correlation performance was different, the WGW sucrose content was highly significant positive correlation with SPS, and significant and highly significant negative correlation with AI and NI, respectively, and the SRW fructose and glucose were significantly positively correlated with the direction of the decomposition of sucrose synthase. In conclusion, grafting on different rootstocks affected the sugar accumulation of watermelon fruits, and wild watermelon grafting increased the total sugar content of fruits, but the percentage of fructose content decreased, and by regulating the activities of enzymes related to the metabolism of sucrose, it may be one of the reasons for the formation of differences in the accumulation of sugar in fruits grafted on different rootstocks.