Effect of Exogenous Sodium Hydrosulfide Mitigating Salt Stress on Chestnut (Castanea mollissima) Seedlings

This study was conducted to investigate the alleviating effect of exogenous hydrogen sulfide on chestnut seedlings under salt stress. The effects of different concentrations of （0, 0.1, 0.2, 0.5, 1.0 and 2.0 mmol/L） sodium hydrosulfide （NariS） on the photosynthesis of ＇Hongli 2＇ chestnut seedlings and the chlorophyll content, proline content and malondialdehyde （MDA） content in chestnut leaves under 100 mM NaCI stress were investigated. According to the results, spraying exogenous NariS had positive effects on photosynthesis of chestnut leaves. The application of NariS could alleviate the damage caused by salt stress on the leaves of chestnut seedlings to different degrees. Compared with the sole treatment with 100 mmol/L NaCI, the chlorophyll content and the proline content were improved. Moreover, MDA content had a significant drop, which effectively reduced the damage of cell membrane under salt stress, The alleviating effect was not obvious with the in- crease of treatment concentration, and the 0.5 and 1.0 mmol/L NariS treatments exhibited better effects.

Foliar application of sodium hydrosulfide(NaHS),a hydrogen sulfide(H2S) donor,can protect seedlings against heat stress in wheat(Triticum aestivum L.)

Temperature extremes represent an important limiting factor to plant growth and productivity. Low concentration of hydrogen sulfide （H2S） has been proven to function in physiological responses to various stresses. The present study evaluated the effect of foliar application of wheat seedlings with a H2S donor, sodium hydrosulfide （NariS）, on the response to acute heat stress. The results showed that pretreatment with NariS could promote heat tolerance of wheat seedlings in a dose-depen- dent manner. Again, it was verified that H2S, rather than other sulfur-containing components or sodion derived from NariS solution, should contribute to the positive role in promoting wheat seedlings against heat stress. To further study antioxidant mechanisms of NariS-induced heat tolerance, superoxide dismutase （SOD, EC 1.15.1.1 ）, catalase （CAT, EC 1.11.1.6） and ascorbate peroxidase （APX, EC 1.11.1.11 ） activities, and HzS, hydrogen peroxide （H2O2）, malonaldehyde （MDA）, and soluble sugar contents in wheat seedlings were determined. The results showed that, under heat stress, the activities of SOD, CAT, and APX, H2S, H2O2, MDA, and soluble sugar contents in NaHS-pretreated seedlings and its control all increased. Meanwhile, NaHS-pretreated seedlings showed higher antioxidant enzymes activities and gene expression levels as well as the H2S and soluble sugar levels, and lower H2O2, MDA contents induced by heat stress. While little effect was detected in antioxidant enzymes activities and soluble substances contents in pretreated wheat seedlings compared with its control under normal culture conditions （data not shown）. All of our results suggested that exogenous NariS could alleviate oxidative damage and improve heat tolerance by regulating the antioxidant system in wheat seedlings under heat stress.

A nanoscale qualitative study on the role of sodium hydrosulfide in oxidized carrollite flotation

The surface species transformation of oxidized carrollite processing with NaHS and KBX was investigated.Flotation and contact angle tests indicate that the combination of NaHS and KBX takes a better flotation performance than adding NaHS or KBX alone.Thermodynamic analysis,X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared(FTIR) results confirm the stronger chemisorption of KBX occurs on the oxidized carrollite surface with NaHS,which is beneficial to remove the cobalt oxides,thus contributing to the superior floatability.Interestingly,less elemental sulfur was observed on the carrollite surface as the interaction of NaHS and KBX than adding NaHS alone.It suggests that elemental sulfur is not the main contributor to the restored floatability of oxidized carrollite through sulfidisation.This study provided a new perspective to correlate the surface species with xanthate adsorption and oxidized carrollite flotation through determining the various intermediate products.