Understanding the Role of Elevated Root Temperatures in Boosting Hydroponic Tomato Growth

Abstract

In the context of global warming, the reliability of agricultural production, considered as a key of long-term importance for the survival and development of human beings, faces increasing environmental and economic challenges, being particularly sensitive to extreme temperatures. Transitioning to sustainable, resilient systems remains critical to maintain global productivity. Higher warming rates have been recorded in soil than in the air, affecting crop yield, which requires further research. This study was conducted to investigate the effects of different root zone warming ranges with varying exposure period on growth traits of roots and shoots of tomato plants (Solanum lycopersicum L.) cv. ‘Roma’. Three temperatures (35, 39, and 45°C) were applied to the roots of tomato, grown hydroponically, at a constant air temperature of 25°C. In order to make a comparison, a non-stress trial was maintained at 25°C. The results showed that moderately high root temperatures of 35°C significantly enhanced tomato growth parameters with improved shoot and root morphological traits, biomass allocation and relative growth rate. Simultaneously, increases were found in tissue hydration, nutrient supply, as well as a relatively maintained membrane stability, identified as key traits for heat tolerance. In contrast, at 39°C and 45°C, tomato plants exhibited a significant decline in growth attributes resulting in altered root and shoot morphology, reduced relative growth rate and dry matter accumulation, membrane disorders leading to nutrient absorption blockage, illustrating a pronounced effect at 45°C in roots compared to aerial organs, which might provide selection system for the appropriate temperature in a hydroponic system.