This study aimed to investigate the metabolic and morphological responses of Italian ryegrass to waterlogging stress during its early growth stage. Waterlogging increased the number of adventitious roots and root porosity, indicating an enhanced oxygen transport mechanism. Phenolic compound levels were increased in both leaf and root tissues under waterlogging stress compared to the control, suggesting the development of a non-enzymatic antioxidant system. Waterlogging treatment also increased reactive oxygen species (ROS) levels only in roots. Total soluble carbohydrates and alcohol dehydrogenase (ADH) activity increased under waterlogging stress, suggesting an increased activity of carbohydrate breakdown and energy conversion mechanisms. This study suggests that Italian ryegrass exhibits significant metabolic and morphological adaptations to waterlogging stress during its early growth stage. These adaptations demonstrate that Italian ryegrass has developed tolerance mechanisms to cope with such stress.

ABSTRACT
Ⅰ. INTRODUCTION
Ⅱ. MATERIALS AND METHODS
    1. Plant growth and stress treatment
    2. Measurement of ROS and total phenol contents
    3. Measurement of total soluble carbohydrate andalcohol dehydrogenase (ADH) activity
    4. Root porosity
    5. Statistical analysis
Ⅲ. RESULTS AND DISCUSSION
Ⅳ. CONCLUSION
Ⅴ. ACKNOWLEDGEMENTS
Ⅵ. REFERENCES

• Min-Jun Kim(Division of Applied Life Science (BK21), IALS, Gyeongsang National University, Jinju 52828, Republic of Korea)
• Myung-Ju Kim(Division of Applied Life Science (BK21), IALS, Gyeongsang National University, Jinju 52828, Republic of Korea)
• Il-Kyu Yoon(Division of Applied Life Science (BK21), IALS, Gyeongsang National University, Jinju 52828, Republic of Korea)
• Chang-Woo Min(Division of Applied Life Science (BK21), IALS, Gyeongsang National University, Jinju 52828, Republic of Korea)
• Byung-Hyun Lee(Division of Applied Life Science (BK21), IALS, Gyeongsang National University, Jinju 52828, Republic of Korea) Corresponding author