Exogenous Tebuconazole and Trifloxystrobin Regulates Reactive Oxygen Species Metabolism Toward Mitigating Salt-Induced Damages in Cucumber Seedling.

Sayed Mohsin,Masayuki Fujita,Mirza Hasanuzzaman,Khursheda Parvin,M Bhuyan

doi:10.3390/plants8100428

Abstract

The present study investigated the role of tebuconazole (TEB) and trifloxystrobin (TRI) on cucumber plants (Cucumis sativus L. cv. Tokiwa) under salt stress (60 mM NaCl). The cucumber plants were grown semi-hydroponically in a glasshouse. Plants were exposed to two different doses of fungicides (1.375 µM TEB + 0.5 µM TRI and 2.75 µM TEB + 1.0 µM TRI) solely and in combination with NaCl (60 mM) for six days. The application of salt phenotypically deteriorated the cucumber plant growth that caused yellowing of the whole plant and significantly destructed the contents of chlorophyll and carotenoids. The oxidative damage was created under salinity by increasing the contents of malondialdehyde (MDA), hydrogen peroxide (H2O2), and electrolytic leakage (EL) resulting in the disruption of the antioxidant defense system. Furthermore, in the leaves, stems, and roots of cucumber plants increased Na+ content was observed under salt stress, whereas the K+/Na+ ratio and contents of K+, Ca2+, and Mg2+ decreased. In contrast, the exogenous application of TEB and TRI reduced the contents of MDA, H2O2, and EL by improving the activities of enzymatic and non-enzymatic antioxidants. In addition, ion homeostasis was regulated by reducing Na+ uptake and enhanced K+ accumulation and the K+/Na+ ratio after application of TEB and TRI. Therefore, this study indicates that the exogenous application of TEB and TRI enhanced salt tolerance in cucumber plants by regulating reactive oxygen species production and antioxidant defense systems.

Highlights

IntroductionEspecially global warming and environmental calamities, severely affect plant productivity worldwide
Climate changes, especially global warming and environmental calamities, severely affect plant productivity worldwide
Phenotypic appearance clearly indicated that salinity inhibited the growth and development of the cucumber plant (Figure 1)

Summary

Introduction

Especially global warming and environmental calamities, severely affect plant productivity worldwide. Salinity is a very common threat to reduce the growth, productivity, and yield of crop plants [2]. Salinity causes osmotic stress [3] as well as ionic toxicity [4], which affect morphological, physiological, and biochemical processes of plants [5]. Salinity reduces the rate of photosynthesis and increases the reactive oxygen species (ROS) formation and, causes oxidative stress by disrupting the antioxidant defense system [1,6]. Salt stress produces significant amounts of ROS (singlet oxygen, 1 O2 , superoxide, O2 − , hydrogen peroxide, H2 O2 , and hydroxyl radical, OH ) [7], which are extremely toxic and cause cell damage, lipid peroxidation, protein denaturing, and programmed cell death [8]

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