通过探究镉胁迫下不同甜瓜幼苗叶片抗氧化酶活力及根系活力变化，为筛选抗镉甜瓜种质提供参考。以野生甜瓜、薄皮甜瓜及厚皮甜瓜为试材，在苗期用不同浓度镉溶液培养后，检测甜瓜幼苗叶片相关酶活及根系活力变化差异。结果表明，镉胁迫下甜瓜幼苗叶片中SOD、POD、CAT、APX活性均低于对照不添加Cd2+。随着Cd2+浓度增大，薄皮甜瓜和厚皮甜瓜幼苗叶片的SOD活性大幅下降，而野生甜瓜幼苗叶片的SOD活性略有回升，且在Cd2+中高浓度(50~100 mg/L)时均以野生甜瓜幼苗叶片的SOD活性最高，薄皮甜瓜的幼苗叶片的SOD活性最低。各处理下野生甜瓜幼苗叶片的POD活性均最高，薄皮甜瓜幼苗叶片的POD活性均最低，随Cd2+胁迫浓度的增大，不同甜瓜材料幼苗叶片的POD活性均下降，但降幅不大。Cd2+胁迫浓度为0 mg/L时，薄皮甜瓜幼苗叶片的CAT活性最高，野生甜瓜幼苗叶片的CAT活性最低；随Cd2+胁迫浓度的增大，薄皮甜瓜幼苗叶片的CAT活性降幅最大。各处理下野生甜瓜幼苗叶片的APX活性均最高，薄皮甜瓜幼苗叶片的APX活性最低，而野生甜瓜幼苗叶片的APX活性随Cd2+浓度增大降幅较大。当Cd2+胁迫浓度为0 mg/L时，野生甜瓜幼苗叶片的Pro含量最低，薄皮甜瓜幼苗叶片的Pro含量最高；随Cd2+胁迫浓度的增大，野生甜瓜幼苗叶片的Pro含量呈变化不明显，薄皮甜瓜则逐步递减，厚皮甜瓜呈先降后升又略下降趋势。各处理下均以厚皮甜瓜幼苗叶片的MDA含量最高，随Cd2+胁迫浓度的增大，野生甜瓜幼苗叶片的MDA含量呈先降后升趋势，薄皮甜瓜的MDA含量呈逐步递减趋势，厚皮甜瓜的MDA含量先升后降又略上升。在相同Cd2+胁迫浓度处理下，野生甜瓜根系活力最强，薄皮甜瓜根系活力降幅最大。由此可见，镉胁迫下薄皮甜瓜幼苗叶片的酶活性降幅较大，厚皮甜瓜次之，野生甜瓜幼苗叶片的酶活性降幅相对较小，且各处理下均以野生甜瓜根系活力最强，这说明参试的薄皮甜瓜对镉胁迫较敏感，野生甜瓜抗镉性较厚皮甜瓜、薄皮甜瓜强。

This study explored the changes of antioxidant enzymeactivities and rootvigor in different melon seedling leaves under cadmium (Cd) stress so as to provide references for selecting Cd-resistant melon germplasm. Wild, thin-skinned and thick-skinned melons were used as experimental materials. After cultivation with different concentrations of cadmium solutions during the seedling stage, the variations in enzyme activity and root vigor in the leaves of different melon seedlings were detected. Results showed that under cadmium stress, the activities of SOD, POD, CAT, and APX in melon seedling leaves were all lower than the control without added Cd??. As the Cd?? concentration increased, the SOD activity in thin-skinned and thick-skinned melon seedlings decreased significantly, while the SOD activity in wild melon seedlings slightly increased. At medium to high Cd?? concentrations(50 to 100 mg/L), the SOD activity in wild melon seedling leaves was the highest, and the SOD activity in thin-skinned melon seedlings was the lowest.Under all treatments, the POD activity in wild melon seedling leaves was the highest, and that in thin-skinned melon seedlings was the lowest. With the increasing concentration of Cd2+ stress, the POD activity in the leaves of different melon materials decreased, but the decrease was not significant. When the Cd2+ concentration was 0 mg/L, the CAT activity in thin-skinned melon seedling leaves was the highest, while that in wild melon seedlings was the lowest. As the Cd2+ concentration increased, the CAT activity in thin-skinned melon seedling leaves decreased the most. Under all treatments, the APX activity in wild melon seedling leaves was the highest, and the APX activity in thin-skinned melon seedling leaves was the lowest. The APX activity in wild melon seedling leaves decreased significantly with increasing Cd2+ concentration. When the Cd2+ stress concentration was 0 mg/L, the Pro content in wild melon seedling leaves was the lowest, and that in thin-skinned melon seedling leaves was the highest. As the Cd2+ concentration increased, the Pro content in wild melon seedling leaves showed no significant change, while the Pro content in thin-skinned melon steadily decreased, and in thick-skinned melon, it decreased initially, then slightly increased, and decreased again.Under all treatments, the MDA content in thick-skinned melon seedling leaves was the highest. As the Cd?? stress concentration increased, the MDA content in wild melon seedling leaves showed a decreasing and then increasing trend, while the MDA content in thin-skinned melon steadily decreased, and that in thick-skinned melon increased initially, then decreased, and slightly increased again. At the same Cd concentration, wild melon exhibited the strongest root vigor, while thin-skinned melon showed the largest decrease in root vigor. It can be concluded that under cadmium stress, thin-skinned melon seedlings showed the largest decrease in enzyme activity, followed by thick-skinned melon, while wild melon seedlings exhibited a relatively smaller decrease. Furthermore, wild melon consistently showed the strongest root vigor under all treatments, indicating that thin-skinned melon is more sensitive to cadmium stress, while wild melon has stronger cadmium resistance compared to thick-skinned and thin-skinned melons.

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甘肃省科技计划资助项目(22CX8NA030)；甘肃省农业科学院生物育种专项(2022GAAS05)；国家自然科学基金项目(31301795)；嘉峪关市科技计划项目(23-25)。