Waterlogging stress is one of the main limiting factors for wheat production, especially in the middle and lower reaches of the Yangtze River in China. Improving the waterlogging tolerance of wheat is an important goal to achieve stable and increased yield in this region. In this study, by exploring the suitable use period and concentration of phytochlorin iron, its role in improving waterlogging stress tolerance was further evaluated mainly from the perspectives of plant photosynthesis and plant antioxidant capacity. The research results could provide the theoretical and technical support for waterlogging-resistant cultivation of wheat.

Using Yangmai 16 as material, three concentrations (0.0875, 0.126, and 0.194 mmol·L^-1) of phytochlorin iron were set at anthesis and grain filling stages to screen the appropriate period and concentration for achieving a significant increase in wheat yield. Based on this, the effect of phytochlorin iron on wheat tolerance to waterlogging stress at anthesis stage was further evaluated.

Compared with control, treatment with a concentration of 0.126 mmol·L^-1 phytochlorin iron at anthesis stage (A2) could significantly increase wheat grain yield by increasing the grain weight. Waterlogging stress at anthesis stage significantly reduced the chlorophyll content, net photosynthesis rate, and post-flowering dry matter accumulation and translocation to grain, resulting in grain yield reduction. However, compared with non-spraying treatment, AW2 treatment showed a higher photosynthetic pigment content, photosystem II stability, net photosynthetic rate. Meantime, the raised activities of antioxidant enzymes, reduced O₂^- production rate and H₂O₂ content, which showed correspondence with the reduced accumulation of malondialdehyde content, thus alleviated the damage of cell membrane lipid peroxidation and the yield reduction caused by waterlogging stress.

Spraying a concentration of 0.126 mmol·L^-1 phytochlorin iron at anthesis stage could significantly increase wheat yield. Phytochlorin iron could alleviate the plant senescence, reduce damage to PSII, enhance the activity of antioxidant enzymes, reduce the damage of cell membrane lipid peroxidation, maintain higher photosynthetic rate, reduce the degree of yield reduction, and enhance wheat tolerance to waterlogging stress.