抄録
In the context of global climate change, the increasing frequency of extreme precipitation events poses a significant threat to the yield stability and security of major food crops, such as sweet potatoes (Ipomoea batatas L.). To systematically elucidate the physiological response mechanisms of sweet potato to waterlogging stress at different growth stages and their effects on yield formation, this study used the cultivar WY18 and applied three waterlogging treatments: during the vine elongation stage, the storage root expansion stage, and the entire growth period. Changes in morphological traits, physiological and biochemical indicators, and yield components were comprehensively analyzed. The results showed that waterlogging significantly reduced the root-to-shoot ratio and relative leaf water content, induced the accumulation of proline and soluble sugars, and markedly enhanced the activities of antioxidant enzymes such as catalase, peroxidase, and superoxide dismutase, indicating that the plant activated its antioxidant defense system to alleviate oxidative damage caused by stress. In terms of yield, waterlogging during the storage root expansion stage resulted in a greater yield reduction than during vine elongation. At the same time, the whole-period stress caused the most severe yield loss, suggesting that the storage root expansion stage is the most sensitive period to waterlogging. Correlation analysis revealed that yield decline was closely associated with plant water imbalance and the intensity of antioxidant responses. The novelty of this study lies in its systematic comparison of sensitivity differences across sweet potato growth stages to waterlogging stress, identification of key mechanisms—such as assimilate allocation shifts and metabolic disorders—that limit yield formation, and determination of the critical sensitive period.
