H2S AND NO SIGNALING INTERACTIONS IN THALE CRESS (ARABIDOPSIS THALIANA L.) AND PEPPER (CAPSICUM ANNUUM L.) LEAVES

This research comprehends a set of experiments with several thale cress (Arabidopsis thaliana L.) and pepper (Capsicum annuum L.) genotypes in controlled conditions using growth chambers, with the aim of determining the physiological role of hydrogen sulfide (H2S) in plants, as well as its potential effect as a signaling compound, particularly in potential interaction with nitric oxide (NO) signaling pathways. Special emphasis was focused on stomatal mechanisms and signaling in their opening and closing. Moreover, the effect of treatment of pepper plants with H2S was investigated in salt stress conditions. It was established that the applied H2S donors, NaHS and GYY4137, inhibit stomata closing in both plant species through the reduction of NO accumulation in stomata, which was proven to occur in SNP or ABA treatment. The effects of NO and H2S were opposite those in pepper plants response to salt stress as well, with increased antioxidative activity in leaf obtained after H2S treatments, and with NaHS in particular. In addition, GYY4137 could be considered as a convenient H2S donor for research into H2S functions in plants. The results point out the interactions of H2S and NO in plant cell signaling in both normal and salt stress conditions. Further research of this type should uncover H2S functions in plant metabolism more precisely, especially considering the potential practical value of this knowledge for plant stress resistance improvement and their productivity enhancement