Effect of different light intensities on the photosynthate distribution in cherry tomato seedlings

To investigate the effect of varying the light intensity on the photosynthate distribution, cherry tomato (Solanum lycopersicum L.) seedlings were grown under different light intensities. It was found that the seedlings under 300 μmol m^–2 s^–1 had a significantly higher dry weight and health index (Health index = Stem diameter/Stem height × Dry weight) than seedlings receiving other light treatments. On the contrary, the biomass, specific leaf mass and health index values of seedlings exposed to 50 μmol m^–2 s^–1 and 550 μmol m^–2 s^–1 were the lowest among all of the treatments. In terms of ¹⁴C-labelled photosynthate translocation, the seedlings under 300 μmol m^–2 s^–1 had lower remaining ¹⁴C-labelled photosynthate (31.45%) compared with other treatments, after ¹⁴CO₂ was supplied for 2 days. The seedlings under 150 μmol m^–2 s^–1 had 36.97% of ¹⁴C-labelled photosynthate in the labelled leaves and transported the obviously higher ¹⁴C-labelled photosynthate to new shoot than others. Together, our results indicate that the photosynthate distribution was the most rational in cherry tomato seedlings at 300 μmol m^–2 s^–1, which enhanced leaf photosynthesis and plant growth.