The Positive Effects of Increased Light Intensity on Growth and Photosynthetic Performance of Tomato Seedlings in Relation to Night Temperature Level

Abstract

Light and temperature are related to the growth and development of plants as well as their energy consumption in plant factories. However, most of the studies to date have focused on light and temperature extremes, while the adaptive responses and underlying mechanisms of plants to non-stress light intensity (LI) and night temperature (NT) largely remain elusive. Here, we investigated the growth and physiological responses of tomatoes grown under three LI regimes of 250 (L_L), 300 (L_M), and 350 (L_H) μmol m⁻² s⁻¹, respectively, combined with two NT conditions. The results revealed that increased LI comprehensively improved tomato growth and physiological status at lower NT levels, but the growth stimulations induced by increasing LI were limited by higher NT. In addition, the lower NT at L_M and L_H conferred a relatively better endogenous physiological condition and significantly promoted tomato growth, but the higher NT significantly accelerated shoot growth at L_L, indicating a compensation of higher NT for low light induced growth restriction. Taken together, the current study suggests that the adaptation mechanism of tomato plants to higher NT varied with LI levels, and higher LI plus lower NT would be an effective strategy to improve tomato growth.