Heavy metal (HM) contamination of agricultural soil is primarily related to anthropogenic perturbations. Exposure to high concentration of HMs causes toxicity and undesirable effects in plants. In this study, the significance of ethylene was studied in response of mustard (Brassica juncea) to a high level (200 mg kg⁻¹ soil) of zinc (Zn) exposure. Plants with high Zn showed inhibited photosynthesis and growth with the increase in oxidative stress. Application of ethylene (as ethephon) to Zn-grown plants restored photosynthesis and growth by inhibiting oxidative stress through increased antioxidant activity, the proline metabolism glyoxalase system, and nutrient homoeostasis. The results suggested that ethylene played a role in modulating defense mechanisms for tolerance of plants to Zn stress.

Salt stress significantly contributes to major losses in agricultural productivity worldwide. The sustainable approach for salinity-accrued toxicity has been explored. The use of plant growth regulators/phytohormones, mineral nutrients and other signaling molecules is one of the major approaches for reversing salt-induced toxicity in plants. Application of the signaling molecules such as nitric oxide (NO) and ethylene (ETH) and major mineral nutrient such as nitrogen (N) and sulfur (S) play significant roles in combatting the major consequences of salt stress impacts in plants. However, the literature available on gaseous signaling molecules (NO/ETH) or/and mineral nutrients (N/S) stands alone, and major insights into the role of NO or/and ETH along with N and S in plant-tolerance to salt remained unclear. Thus, this review aimed to (a) briefly overview salt stress and highlight salt-induced toxicity, (b) appraise the literature reporting potential mechanisms underlying the role of gaseous signaling molecules and mineral nutrient in salt stress tolerance, and (c) discuss NO and ETH along with N and S in relation to salt stress tolerance. In addition, significant issues that have still to be investigated in this context have been mentioned.

Plants encounter several abiotic stresses, among which heat stress is gaining paramount attention because of the changing climatic conditions. Severe heat stress conspicuously reduces crop productivity through changes in metabolic processes and in growth and development. Ethylene and hydrogen sulfide (H₂S) are signaling molecules involved in defense against heat stress through modulation of biomolecule synthesis, the antioxidant system, and post-translational modifications. Other compounds containing the essential mineral nutrient sulfur (S) also play pivotal roles in these defense mechanisms. As biosynthesis of ethylene and H₂S is connected to the S-assimilation pathway, it is logical to consider the existence of a functional interplay between ethylene, H₂S, and S in relation to heat stress tolerance. The present review focuses on the crosstalk between ethylene, H₂S, and S to highlight their joint involvement in heat stress tolerance.

In the present study, the potential of ethylene as ethephon (an ethylene source) was investigated individually and in combination with split doses of nitrogen (N) and sulfur (S) soil treatments for removal of the damaging effects of salt stress (100 mM NaCl) in mustard (Brassica juncea L.). Plants were grown with 50 mg N plus 50 mg S kg⁻¹ soil at sowing time and an equivalent dose at 20 days after sowing [N50 + S50]_{0d and 20d}. Ethephon at 200 μL L^‒1 was applied to combined split doses of N and S with or without NaCl. Plants subjected to NaCl showed a decrease in growth and photosynthetic characteristics as well as N and S assimilation, whereas proline metabolism and antioxidants increased. The application of ethephon to plants grown with split N and S doses significantly enhanced photosynthetic efficiency by increasing the assimilation of N and S, improving the concentration of proline and induction of the antioxidant system with or without NaCl. The regulation of ethylene and/or split forms of N and S application may be potential tools for not just overcoming salt stress effects in this species and in related Brassicaceae but also enhancing their photosynthesis and growth potential through increased nutrient assimilation.

During climate change, various unparalleled perils to agricultural systems have been observed worldwide. The detrimental impacts of heavy metal toxicity (HMs) lead to a considerable decrease in crop productivity and yield, thereby putting the agricultural system at risk and exerting a significant impact on food production. This has sparked significant worry regarding the achievement of the sustainable development goals (SDGs) pertaining to ensuring food and nutritional security for the constantly growing global population. In the current study, we have endeavored to reveal the significance of salicylic acid (SA) under arsenic (As) stress conditions in rice (Oryza sativa) plants. Being a toxic metalloid, As has adverse effects on the efficiency of photosynthesis and the assimilation of nitrogen (N) and sulphur (S) growth, and also causes alterations in defense systems and ethylene biosynthesis. The study revealed that the positive influence of SA in promoting nutrient metabolism, photosynthesis and growth under As stress was the result of its interplay with ethylene biosynthesis and the enhanced capacity of defense systems to reduce oxidative stress-mediated cellular injuries and cell deaths. In conclusion, SA can be considered a crucial physiological criterion for the development of As-tolerant rice plants.