Effect of hydrogen sulfide (H2S) on the growth and development of tobacco seedlings in absence of stress

Abstract

Background: Hydrogen sulfide (H₂S) is a novel signaling molecule involved in the growth and development of plants and their response to stress. However, the involvement of H₂S in promoting the growth and development of tobacco plants is still unclear.

Results: In this study, we explored the effect of pre-soaking or irrigating the roots of tobacco plants with 0.0, 2.0, 4.0, 6.0, and 8.0 mM of sodium hydrosulfide (NaHS) on endogenous H₂S production, antioxidant enzymatic and cysteine desulfhydrase activities, seed germination, agronomic traits, photosynthetic pigments contents, and root vigor. The results revealed that exogenous NaHS treatment could significantly promote endogenous H₂S production by inducing gene expression of D/L-CD and the activities of D/L-CD enzymes. Additionally, a significant increase in the agronomic traits and the contents of photosynthetic pigments, and no significant difference in carotenoid content among tobacco plants treated with 0.0 to 8.0 mM of NaHS was observed. Additionally, a significant increase in the germination speed, dry weight, and vigor of tobacco seeds, whereas no significant effect on the percentage of seed germination was observed on NaHS treatment. Furthermore, NaHS treatment could significantly increase the activity of superoxide dismutase (SOD) and peroxidase (POD) enzymes, which reduces damage due to oxidative stress by maintaining reactive oxygen species homeostasis.

Conclusions: These results would aid in enhancing our understanding of the involvement of H₂S, a novel signaling molecule to promote the growth and development of tobacco plants.

Keywords: Enzymes activities; Hydrogen sulfide; NaHS; Photosynthetic pigments; Tobacco.

Fig. 1

The content of the endogenous H₂S in tobacco treated with 0.0, 2.0, 4.0, 6.0, and 8.0 mM of NaHS for 1, 12, 24, and 48 h, respectively. The results are the mean of three replicates, and the error bars show the standard deviation (SD). Different letters in lowercase denote significant differences between treatment groups at the 5% level, according to Duncan’s test

Fig. 2

The effect of 0.0, 2.0, 4.0, 6.0, and 8.0 mM of NaHS on the enzyme activities of LCD (A) and DCD (B), along with LCD (C) and DCD (D) expression profiles. The results are the mean of three replicates, and the error bar shows SD. Different letters in lowercase denote significant differences between treatment groups at the 5% level, according to Duncan’s test

Fig. 3

The germination and morphology of tobacco seeds treated with 0.0, 2.0, 4.0, 6.0, and 8.0 mM NaHS for 14 days

Fig. 4

The effect of 0.0, 2.0, 4.0, 6.0, and 8.0 mM of NaHS on tobacco agronomic traits

Fig. 5

The effect of 0.0, 2.0, 4.0, 6.0, and 8.0 mM of NaHS on Chl a, Chl b, and carotenoid contents. A The contents of Chl a in the extracted fresh leaves treated with NaHS on 0 day and 15 days. B The contents of Chl b in the extracted fresh leaves treated with NaHS on 0 day and 15 days. C The contents of carotenoid in the extracted fresh leaves treated with NaHS on 0 day and 15 days. Different letters in lowercase denote significant differences between treatment groups at the 5% level, according to Duncan’s test

Fig. 6

The effects of 0.0, 2.0, 4.0, 6.0, and 8.0 mM NaHS on the activity of tobacco roots after 15 days. Bars represent the mean ± SE. Different letters in lowercase denote significant differences between treatment groups at the 5% level, according to Duncan’s test

Fig. 7

The effects of 0.0, 2.0, 4.0, 6.0, and 8.0 mM of NaHS on the SOD (A) and POD (B) enzymatic activities in tobacco plants treated for 0, 5, 10, and 15 days. Bars represent the mean ± SE. Different letters in lowercase denote significant differences between treatment groups at the 5% level, according to Duncan’s test