Heat Stress at Early Reproductive Stage Differentially Alters Several Physiological and Biochemical Traits of Three Tomato Cultivars

Md Sabibul Haque,Md Nesar Uddin,Md Alamgir Hossain,Abul Khayer Mohammad Golam Sarwar,Omar M Ali,Arafat Abdel Hamed Abdel Latef,Mst Tanziatul Husna,Akbar Hossain

doi:10.3390/horticulturae7100330

Md Sabibul Haque, Md Nesar Uddin + Show 6 more

Open Access

https://doi.org/10.3390/horticulturae7100330

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Abstract

Global warming is predicted to be increased in the upcoming years, resulting in frequent heatwaves or hot days worldwide, which can seriously affect crop growth and productivity. The responses of heat stress to several photophysiological and biochemical traits in three tomato cultivars were investigated in a pot experiment, and the heat tolerance capability of these cultivars was evaluated based on the investigated traits. The experiment was followed by a factorial completely randomized design, and the factors were (i) tomato cultivars (BARI Hybrid Tomato-5, BARI Tomato-14, and BARI Tomato-15) and (ii) heat stress (control and heat). The plants of three tomato cultivars were exposed to short-term heat stress (four days at 38/25 °C day/night temperature) at the flowering stage. The measured traits such as dry mass, leaf greenness (SPAD), maximum photochemical efficiency of photosystem II (Fv/Fm), photosynthetic rate (A), stomatal conductance (gs), transpiration rate (E), leaf chlorophyll, and carotenoid content were significantly declined, while the catalase and ascorbate peroxidase activities were increased by heat stress in all three tomato cultivars except BARI Tomato-15, which showed unaltered gs, E, and carotenoids. The percent reduction (over control) in SPAD, Fv/Fm, A, total chlorophyll, and total carotenoids was significantly lower (11, 06, 25, 34, and 19%, respectively), whereas the percent increase in catalase and ascorbate peroxidase activities was substantially higher (70 and 72%, respectively) in BARI Tomato-15 than in other cultivars. Based on the measured physiological and biochemical traits, the cultivar BARI Tomato-15 showed better heat tolerance than the other cultivars.

Highlights

Heat stress had a substantial effect on photophysiological processes and biochemical parameters such as pigment concentrations and antioxidative enzyme activity in three tomato cultivars, and analysis of variance (ANOVA) analysis revealed the sources of variance (Table 2)
The results indicated that heat stress had a substantial and differential effect on all of the assessed parameters, including leaf greenness (SPAD), maximal photochemical efficiency of photosystem II (PSII), photosynthesis, chlorophyll, and antioxidant activities, among the three cultivars studied
There are a set of enzymes involved in chlorophyll synthesis that undergo deactivation due to heat stress [12,31], and the accelerated degradation of chlorophyll is more pronounced in the developed leaf [32]

Summary

Introduction

During the 20th century, an increase of 0.74 ◦ C in global surface temperature was reported, while climate models predicted a further rise of 1.1 to 6.4 ◦ C global mean temperature during the century [1]. Heatwaves due to global climate change have made crop production more vulnerable, and the world is under crisis for agricultural production and food security [2]. Climate simulation studies have shown that in contrast to twice a century, hot summers are predicted to occur twice a decade in the future during the 2000s [3]. Tomato (Solanum lycopersicum L.) is an important and popular vegetable globally, including in Bangladesh. Tomato is a heat-sensitive crop and is usually grown in the winter season in Bangladesh for its optimum growth and yield.

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