Photosynthetic Induction Under Fluctuating Light Is Affected by Leaf Nitrogen Content in Tomato

• DOI: 10.3389/fpls.2022.835571
• Publication Date: 2022-02-17T05:32:25Z
• Authors: Hu Sun; Yu-Qi Zhang; Shi-Bao Zhang; Wei Huang
• Keywords: Impacts of Elevated CO2 and Ozone on Plant Physiology; Chlorophyll; 0106 biological sciences; fluctuating light; Nitrogen; Plant physiology; mesophyll conductance; Organic chemistry; Plant Science; Stomatal conductance; Horticulture; Solanum; 01 natural sciences; nitrogen; SB1-1110; Molecular Mechanisms of Photosynthesis and Photoprotection; Agricultural and Biological Sciences; Photosynthetic Acclimation; photosynthetic limitation; Biochemistry, Genetics and Molecular Biology; Photoinhibition; Nitrogen Assimilation; Photosynthesis; Molecular Biology; Biology; 2. Zero hunger; Global and Planetary Change; photosynthesis; Global Forest Drought Response and Climate Change; Botany; Plant culture; Life Sciences; 15. Life on land; Agronomy; Chemistry; Environmental Science; Physical Sciences; Carbon assimilation; Chlorophyll fluorescence

The response of photosynthetic CO2 assimilation to changes of illumination affects plant growth and crop productivity under natural fluctuating light conditions. However, the effects of nitrogen (N) supply on photosynthetic physiology after transition from low to high light are seldom studied. To elucidate this, we measured gas exchange and chlorophyll fluorescence under fluctuating light in tomato (Solanum lycopersicum) seedlings grown with different N conditions. After transition from low to high light, the induction speeds of net CO2 assimilation (AN), stomatal conductance (gs), and mesophyll conductance (gm) delayed with the decline in leaf N content. The time to reach 90% of maximum AN, gs and gm was negatively correlated with leaf N content. This delayed photosynthetic induction in plants grown under low N concentration was mainly caused by the slow induction response of gm rather than that of gs. Furthermore, the photosynthetic induction upon transfer from low to high light was hardly limited by photosynthetic electron flow. These results indicate that decreased leaf N content declines carbon gain under fluctuating light in tomato. Increasing the induction kinetics of gm has the potential to enhance the carbon gain of field crops grown in infertile soil.