Effects of Root Cooling on Plant Growth and Fruit Quality of Cocktail Tomato during Two Consecutive Seasons

Abstract

Understanding the effects of root temperature on plant growth and key food components of horticultural crops under greenhouse conditions is important. Here, we assess the impact of root cooling on plant growth and fruit quality of two cocktail tomato cultivars (Lycopersicon esculentum cv “Amoroso” and cv “Delioso”) during the winter of 2017-2018 and the summer of 2018. Plants were grown hydroponically on rockwool under different root temperatures (16–27°C and 10°C) from the 2nd inflorescence to harvest inside the greenhouse. A root temperature of 10°C was controlled independently from air temperature (18–23°C in winter and 21–29°C in summer) by circulating cooling water. Reductions of marketable yield per plant (7.9–20.9%) in both cultivars were observed in response to root cooling in winter, but not significantly in summer. In most cases, root cooling had a positive effect on the functional quality (sugars, vitamin C, and carotenoids levels). In the case of “Delioso,” glucose concentration increased by 7.7–10.3%, vitamin C by 20–21%, and lycopene by 16.9–20.5% in both seasons. “Amoroso” exhibited only higher consistent values in glucose with increments between 6.9 and 7.8% in the two seasons. The levels of elements decreased by root cooling, with statistically significant reduction of N, P, S, and Fe by 12.1–15.7% in “Delioso” in winter and P and Zn by 9.1–22.2% in both cultivars in summer. Thus, manipulation of root temperature could be a feasible method to improve the overall fruit quality of cocktail tomato; however, this effect was also dependent on cultivars and other environmental factors.

The Effects of Root Temperature on Growth, Physiology, and Accumulation of Bioactive Compounds of Agastache rugosa

“…Similarly, the nutrient solution at 10 • C was beneficial for raising both RA and luteolin concentrations and the contents of the whole plant in red perilla (Perilla frutescens, Labiatae) [10]. Bioactive compounds in the tomatoes (Solanum lycopersicum L.) were increased under cold stress at 10 • C [39]. Low root temperature at 10 • C caused water stress, which increased the sugar concentrations in the tomatoes [39].…”

“…Bioactive compounds in the tomatoes (Solanum lycopersicum L.) were increased under cold stress at 10 • C [39]. Low root temperature at 10 • C caused water stress, which increased the sugar concentrations in the tomatoes [39]. Furthermore, the high RZT treatment at 33 • C increased the total phenolic compound content in the carrots (Daucus carota L.) [14].…”

Effects of Soil Type on Trace Element Absorption and Fruit Quality of Pepper

“…Recently, research on the nutritional value of crops under different soil conditions (roots) has received increasing attention ( Jansen et al, 2012 ; He et al, 2019 ). Bao et al (2006) investigated the soil nutrient status of Newhall navel orange orchard in Hubei Province and its effect on fruit quality.…”

Effects of Short-Term Root Cooling before Harvest on Yield and Food Quality of Chinese Broccoli (Brassica oleracea var. Alboglabra Bailey)

“…In hydroponically grown carrots, a 14-day treatment with an elevated nutrient solution temperature increased the total phenolic compounds and soluble solid content [10]. Similarly, our previous studies of the effects of root temperature on food quality of Chinese broccoli [14] and cocktail tomato [15] have shown that long-term root cooling can be used as a strategy to accumulate high levels of phytochemicals such as sugar, chlorophyll, lycopene and glucosinolates with potential practical applications.…”