Effects of Different Waterlogging Times on Growth Status and Physiological Characteristics of Sugar Beet Seedlings

As global temperatures warm and the frequency of extreme precipitation increases, sugar beet ( Beta vulgaris L.) growth and yield are highly vulnerable to flooding and persistent heavy rainfall. The present study was designed to investigate the duration-dependent changes in the growth status and physiological characteristics of sugar beet seedlings in response to waterlogged stress. Sugar beet seedlings were subjected to waterlogging for 5, and 10 days during the seeding stage. The present study showed that waterlogging inhibited the growth and development of sugar beet seedlings. After 5 and 10 days of the waterlogging, fresh weight of the whole plant was 42.6 and 50.5% lower than the controls, respectively. Waterlogging increased the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) enzymes, and decreased soluble protein (SP), proline (Pro), photosynthetic pigment content and soil redox potential (Eh). During the first 5 days of the waterlogging, relative electrical conductivity and malondialdehyde (MDA) content remained unchanged. Notably, primary root growth of sugar beet seedlings was inhibited and degraded under waterlogged stress but waterlogging induced seedlings to produce a large number of adventitious roots (AR). We conclude that sugar beet seedlings survive under waterlogged stress using physiological regulation, and morphological acclimation.