Abstract:

The study aims to explore the effects of different soil salinity and alkalinity on the growth and photosynthetic characteristics of sugar beet seedlings under waterlogging stress, and to verify the growth law of sugar beet under waterlogging stress and provide a theoretical basis for the evaluation of the impact of waterlogging stress on sugar beet planting in saline-alkali land. We used ‘SV1433’ as the research material, and NaCl, Na₂SO₄, Na₂CO₃ and NaOH to adjust soil salinity and alkalinity for three soil saline-alkali gradients, which were slightly acidic soil, saline soil and salinity-alkalinity soil. Indoor soil culture was carried out with six treatments, including the three soil saline-alkali gradients under both CK (without waterlogging stress) and waterlogging stress. The results showed that the seedling emergence of sugar beet in slightly acidic soil was faster than that in saline soil and saline-alkali soil after 9 days of sowing. After 26 days of sowing, at three soil saline-alkali gradients of slightly acidic soil, saline soil and saline-alkali soil under waterlogging stress, compared with CK, the fresh weight decreased by 40.7%, 26.9% and 25.2%, respectively, the dry weight decreased by 41.1%, 29.9% and 24.8%, respectively, and the plant height decreased by 20.4%, 19.1% and 16.3%, respectively. It was shown that the effects of waterlogging stress on fresh weight, dry weight and plant height of sugar beet seedlings decreased gradually with the increase of soil salinity and alkalinity. Under waterlogging stress, the area of seedling root and leaf and the leaf length decreased significantly, so did the net photosynthetic rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) of leaves, indicating that the growth of sugar beet seedlings in saline-alkali soil was better than that in saline and slightly acidic soil under waterlogging stress.

Key words: sugar beet, waterlogging stress, soil salinity and alkalinity, growth and development, photosynthesis