Application of Chlorophyll Fluorescence Imaging for Assessing the Recovery of Kimchi Cabbage Seedlings from Drought Stress

This study aimed to develop drought tolerance indicators in kimchi cabbage (Brassica rapa ssp.pekinensis) seedlings by integrating chlorophyll fluorescence (CF) imaging parameters with morphological and physiological traits during post-drought recovery.Seedlings of two cultivars, 'Bulam3ho' and 'Hwipalam', were exposed to 5 days of water deficit treatment followed by 12 days re-watering period.Drought stress markedly reduced plant leaf area, plant fresh weight, and leaf water content, while increasing dry matter content.Gas exchange traits, including the net photosynthetic rate, transpiration, and stomatal conductance, declined significantly, whereas the intercellular CO 2 concentration increased under drought stress and gradually decreased during the recovery period, indicating a transition from stomatal to non-stomatal limitation of photosynthesis.CF parameters, particularly F v /F m and F v /F 0 , decreased under drought but gradually recovered upon re-irrigation, which indicated reversible photoinhibition of photosystem II.Following re-irrigation, the two cultivars showed distinct recovery dynamics.'Bulam3ho' recovered more rapidly in terms of growth, development, and photosynthetic activity, whereas 'Hwipalam' recovered slowly with greater photochemical stability.These results demonstrate distinct recovery strategies between the two cultivars, reflecting their different physiological responses to drought.Moreover, significant correlations among CF indices, gas exchange traits, and morphological parameters demonstrate that CF imaging parameters serve as reliable and non-destructive indicators of drought response and recovery.These findings highlight the potential of CF-based phenotyping for high-throughput screening and breeding of drought-resilient kimchi cabbage cultivars.