Table 2.

Selected studies on the crucial role of H₂S in heat stress tolerance. NAHS, sodium hydrogen sulfide.

S. No.	Plant	H2S Source	Temperature Range	Response	References
1.	Fragaria	100 µM NAHS	42 °C	Increased activity of antioxidant enzymes and increased expression of antioxidant enzymes	[131]
2.	Nicotiana tabacum	50 µM NAHS	42 °C	Increased vitality of cells and alleviated electrolyte leakage	[122]
3.	Nicotiana tabacum	50 µM NAHS	43 °C	Increased S-containing compounds such as cysteine and glutathione as well as antioxidant enzymes	[132]
4.	Zea mays	1.2 mmol NAHS	47 °C	Decreased oxidative stress and upregulated antioxidant defense system	[133]
5.	Zea mays	1.5 mmol NAHS	38 °C	Increased proline biosynthesis	[134]
6.	Zea mays	0.5 mmol NAHS	47 °C	Increased betaine accumulation	[135]
7.	Zea mays	500 µM NAHS	48 °C	Increased endogenous H2S accumulation	[132]