Growth and Physiological Responses of Capsicum frutescens Seedlings to Waterlogging Stress

Capsicum frutescens strains ‘ZHC1’‘ZHC2’ and ‘ZHS2’ with different waterlogging tolerance were used as test materials.The effects of waterlogging stress on seedling growth and physiological indexes of pepper were studied by simulating short-term waterlogging stress, in order to explore the waterlogging tolerance mechanism of pepper.The results showed that the stem diameter of these peppers increased significantly at the 24 hours after the waterlogging treatment（W24 h）;the fresh weight and dry weight of waterlogging-tolerant ‘ZHC2’ plants were higher than those of the control.The plant height of ‘ZHC2’ and ‘ZHS2’（medium waterlogging tolerance） was significantly higher than that of the control at the 24 hours after the recovery（R24 h）.Waterlogging stress promoted the shallow root distribution and adventitious root formation in ‘ZHC2’ and ‘ZHS2’.The chlorophyll of ‘ZHC2’ was less damaged by waterlogging stress, and the carotenoid content increased under the waterlogging stress.The contents of soluble sugar and proline in three pepper lines increased under the waterlogging stress.The MDA contents of the leaves and roots in ‘ZHC2’ were the lowest, while those in ‘ZHC1’ were the highest.In conclusion, thick stem, root shallow distribution, adventitious root formation, less damage to chlorophyll, and the content increase of carotenoid, soluble sugar and proline might contribute to waterlogging tolerance and growth recovery of ‘ZHC2’.Adventitious root formation and contents of carotenoid and malondialdehyde were important indexes for waterlogging-tolerant identification of Capsicum frutescens.