Effect of sodium nitroprusside on growth, physiological and biochemical characters of Solanum tuberosum cv. Agria under salinity stress on in vitro condition

Salinity stress is the certain factor that seriously constrains agricultural production in various regions especially in arid and semi-arid areas. Nitric oxide is a bioactive molecule that synthesis via enzymatic and non-enzymatic pathways under stress conditions in different organs of plant, regulates and adjustments defense reactions of plant. Sodium nitroprusside (SNP) is used as a releasing compound of nitric oxide. Many studies have shown that this compound can protect plant under oxidative stresses and maintain chlorophyll. SNP could improve the effects of salinity and increased chlorophyll in cotton. Salinity is a serious environmental stress in the regions around Urmia Salt Lake and grapevine is one of the most economically important fruit crops in south west of Iran. This study was investigated the effect of sodium nitroprussdie as a nitric oxide donor, on growth characters (leave number, plantlet height, fresh and dry weight), physiological (chlorophyll a, b and carotenoids) and biochemical (antioxidant activity, total phenol, protein and glycine betaine) characters of Solanum tuberosum cv. Agria under salinity stress on in vitro condition. For treatment the single node of S. tuberosum cv. Agria stem were cultured in MS medium with half concentration of macro and micro elements contained four levels of sodium nitroprosside (0, 10-3, 10-4 and 10-5 mM) and two levels of salinity (0 and 70 mM). Obtained results showed that under salinity stress leaves number, height and fresh and dry weight of plantlets decreased, also chlorophylls, carotenoids, protein and total phenol of plantlets showed significant reduction. In contrast, antioxidant activity and glycine betaine content of in vitro plantlets significantly increased. Application of sodium nitroprusside in media culture caused to improvement of growth, physiological and biochemical characters under salinity stress. In conclusion, antioxidant activity, total phenol and protein were decreased by application salinity stress. In addition, antioxidant activity and glycine betaine content during salt stress period was decreased application of nitric oxide. The glycine betaine content of plantlets in general condition with application of sodium nitroprosside increased but under salinity stress, sodium nitroprosside had negative effect on glycine betaine content. The results of this research showed that with increasing antioxidant activity, total phenol, protein can tolerate salt solution and also applying the SNP enhance plant tolerance to salinity. Further studies are necessary to determine optimum concentration and duration of NO application in order to achieve maximum benefit of this chemical in Solanum tuberosum tissue culture