INFLUENCE OF HYDROGEN SULFIDE ON SUNFLOWER (Helianthus annuus L.) SEED VIGOR IN DROUGHT STRESS

Sumporovodik (H2S) kao signalna molekula ima veliku značajnost u odgovoru na biotski i abiotski stres. Cilj istraživanja je bio utvrditi utjecaj primiranja sjemena suncokreta (Helianthus annuus L.) otopinama natrij hidrogen sulfida (NaHS) rastućih koncentracija (100, 500, 1000 i 1500 μM) te vodom, na pokazatelje vigora i molekularne pokazatelje stresa u klijancima naklijavanim na različitim otopinama PEG-6000 (H2O; 2,5 %; 5 %; 10 %). Tretmani s NaHS, su u prosjeku za sve varijante osmotskog stresa povećali klijavost. Na 5 % PEG primiranje s NaHS je rezultiralo povećanjem energije klijanja kod svih koncentracija primijenjenog donora H2S. U usporedbi s sjemenom primiranim u vodi i ne primiranim sjemenom, tretmani s NaHS su rezultirali povećanjem mase klijanaca. Pri najvišoj razini osmotskog stresa, osmoprimiranje sjemena s NaHS je smanjilo razinu lipidne peroksidacije. U klijancima suncokreta, čije sjeme je prethodno primirano otopinama NaHS, a potom naklijavano na vodi, utvrđen je smanjeni sadržaj vodikovog peroksida. Sadržaj slobodnog prolina, pri osmotskom stresu 2,5 % PEG, u prosjeku se povećavao s povećanjem koncentracije NaHS. Dobiveni rezultati upućuju na stimulativno djelovanje H2S na klijavost i masu klijanaca. Povećana akumulacija slobodnog prolina u stanici te smanjenje lipidne peroksidacije i vodik peroksida upućuje na moguću zaštitnu ulogu ovog spoja u uvjetima osmotskog stresa. Djelovanje različitih koncentracija NaHS pri pojedinim razinama stresa je bilo različito, stoga su potrebna daljnja istraživanja uloge H2S u uvjetima osmotskog stresa.Hydrogen sulfide (H2S) as a signaling molecule has a great significance in response to biotic and abiotic stress. The aim of the research was to determine the effect of seed priming of sunflower (Helianthus annuus L.) with increasing concentrations of sodium hydrogen sulfide (NaSH) solutions (100, 500, 1000 and 1500 μM), on the indicators of seed vigor and molecular indicators of stress, in seedlings germinated on different solutions of PEG-6000 (H2O; 2.5 %; 5 %; 10 %). In average for all the osmotic stress levels, treatments with NaSH increased germination capacity. At 5 % of PEG, priming with NaSH resulted in increased germination capacity at each concentration of the H2S donors applied. As compared to the water primed or non primed seed, treatments with NaSH increased mass of seedlings. At the highest level of osmotic stress NaSH reduced the level of lipid peroxidation. In seedlings grown from the seed pre treated with NaSH solutions and germinated on water, reduced content of hydrogen peroxide was observed. Content of free proline at 2.5 % PEG, increased with increasing concentrations of NaSH. The results suggest a stimulatory effect of H2S on the germination capacity and seedling weight. The increased accumulation of free proline, decreased lipid peroxidation levels and hydrogen peroxide content, indicating a possible protective role of H2S in seedlings, grown under osmotic stress. The effect of different concentrations of NaSH at certain levels of stress were different, hence further research on the role of H2S under conditions of osmotic stress is needed