Effects Of Plant Growth And Antioxidant Quality By Selenium Sulphur Interaction In Pakchoi (Brassica Campestris Ssp Chinensis L.)

Effects of different concentrations of selenium and sulphur supply on plant growth and nutrientabsorption were studied in pakchoi (Brassica campestris ssp chinensis L.), which was cultured byhydroponic solution. Not only did the effects of different concentrations of selenium and sulphur onsulfhydryl compounds, glutathione and glucosinolate in plant were studied, but also effects ofdifferent concentrations of selenium and sulphur on total phenols, flavonoids and ascorbic acid inplant were also studied. The results showed as follows；1. Effects of different concentrations of selenium (0,5,10,15μM) and sulpur (0.2,1mM)interaction effects on plant growth and nutrient absorption were studied in pakchoi. Resultsshowed that, at low sulfur level (0.2mM), the pakchoi fresh weight decreased as seleniumapplication increasing (p<0.05)；Meanwhile, at normal sulfur level (1mM), there was nosignificant influence on fresh weight with selenium treatment. There was a significant influenceon selenium and sulfur content in pakchoi shoots and roots (p<0.05), while increasing sulfurapplication significantly reduced selenium content. At low sulfur level (0.2mM), as increasingselenium application, contents of Ca, Mg, B in pakchoi shoots and roots were increased (p<0.05),but contents of P, K, Fe, Mn were affected. Under normal sulphur level (1mM), with increasingselenium supply, Ca, Mg, Fe, Mn content in pakchoi shoots and roots were decreased (p<0.05),but did not affect the content of P, Cu, Zn and B.2. Effects of selenium (0,5,10,15μM) and sulphur (0.2,1mM) treatments on sulfhydrylcompounds, glutathione and glucosinolate were studied in plant cultured by hydroponic solution.The results showed that at low sulphur lever (0.2mM), with increasing selenium supply, thecontent, which did not reach the significant level, of sulfhydryl compounds and glutathionecontent were decreased. Then, at normal sulphur level (1mM), as increasing selenium supply,sulfhydryl compounds and GSH content of pakchoi shoots were increased, but did not reach thesignificant level. There was appreciable impact on glucosinolate content with selenium sulfurinteractions treatment in the shoots and root of pakchoi (p<0.05). At low sulphur lever (0.2mM),content of aliphatic glucosinolate and aromatic glucosinolate in pakchoi were decreasing byincreasing selenium supply. At normal sulphur level (1mM), aliphatic glucosinolate and total glucosinolates content were decreased by increasing selenium supply.3. Effects of selenium (0,5,10,15μM) and sulphur (0.2,1mM) treatments on antioxidant andantioxidant activity in plant were also studied. The results showed that at lower level of sulfur(0.2mM), the content of VC in pakchoi was reduced remarkablely by increasing seleniumapplication (p<0.05), while under normal level of sulfur (1mM), increasing seleniumconcentration decreased flavonoids content, which did not reach the significant level. The resultsalso showed that with treatment of selenium sulfur interaction, there was a significant influenceon total phenolic content, DPPH radical scavenging activity and FRAP value (p<0.05). At lowsulfur level (0.2mM), total phenolic content in pakchoi was higher than that under normal sulfurlevel (1mM). While, at normal sulfur level (1mM), DPPH radical scavenging activity and FRAPvalue were higher than that at low sulfur level (0.2mM).