Influence of exogenous selenomethionine and selenocystine on uptake and accumulation of Se in winter wheat (Triticum aestivum L. cv. Xinong 979).

Soil selenium (Se) is mainly inorganic including selenate and selenite but organic forms such as selenomethionine (SeMet) and selenocystine (SeCys) are commonly present. Although organic Se is bioavailable or potentially bioavailable to plants, whether the effects of the organic Se on uptake and accumulation of Se in winter wheat differ in forms is still not clear. Both hydroponic experiments and a pot trial of whole plant growth stage were conducted to investigate the effects of SeMet and L-selenocystine (SeCys) on uptake and accumulation of Se in winter wheat (Triticum aestivum L. cv. Xinong 979). Not only metabolic inhibitor (carbonyl cyanide m-chlorophenylhydrazone (CCCP)) inhibited SeMet (44%) influx into wheat roots but also aquaporin inhibitor (AgNO) or putative inhibitor (HSiO and HBO) suppressed 83%, 62%, or 64% SeMet influx into the roots. However, these inhibitors had insignificant effects on SeCys influx into the roots. Wheat grain possessed more effective Se accumulation under SeCys treatments than under SeMet treatments, which was contributed to more efficiently translocation of Se from husk to grain, more remobilization of tissue Se to grain, and significantly higher concentration of soluble Se (SOL-Se) and exchangeable and carbonate-bound Se (EXC-Se) in the rhizosphere of winter wheat. The present study indicated that the effects of organic Se on uptake and accumulation of Se in winter wheat differed in forms and that SeCys exhibited the potential to increase grain Se concentration in winter wheat. The results from the present study will replenish information about the effects and related mechanisms of SeMet or SeCys on uptake and accumulation of Se in winter wheat and provide insights of effects of organic Se on wheat grain Se accumulation.