Uptake, distribution and accumulation of selenium by ryegrass

The deficiency or excess of selenium (Se) in the environment has been found to be associated with a variety of diseases in humans (Kashan and Kashin-Beck disease) and domestic animals (White-muscle disease and embryo deformity or death) . However, a direct cause and effect relationship is difficult to be demonstrated. Humans and domestic animals acquire Se mainly from soil-plant-water system in which plant is an immediate source of Se. Accumulative experimental evidence indicated an important influence of Se on the growth and quality of plants, though whether Se is an essential nutrient to higher plants is still indefinite. Much work has been done in studying uptake and accumulation of Se and its effects on the growth and physiologic activities for the crops and vegetables, but less work has been done with the ryegrass (Lolium multiflorm , Lamaubada) .This paper dealt with the uptake, distribution and accumulation of Se by ryegrass and the effects of Se on the biomass of ryegrass using a nutrient solution culture approach. This experiment consisted of 6 treatments: 0, 0.01, 0.05 , 0.1, 1.0 and 10.0 mg/L of Se as Na2SeO3. The results indicated that the Se content of ryegrass at different stages decreased in the order of tillering stage jointing stage earing stage seedling stage; The difference of Se content in different period of duration was not obvious when SeO32--Se concentration was lower( Se4+0.05 mg/L) ; Se content of ryegrass increased with the increase of added SeO32--Se within non-poisonous range. The order of Se content was root leaf stem at different SeO32--Se concentration, the majorities of SeO32--Se taken up by ryegrass were accumulated in roots with less amount of Se translocated to shoots. The growth of ryegrass was promoted at lower SeO32--Se concentration (0-0.1 mg/L) while it was restrained or poisoned at higher SeO32-- Se concentration ( Se4+ 1.0 mg/L) ; The biomass of ryegrass increased with the increasing of added SeO32--Se within non-poisonous range(Se4+0.1 mg/L) . The accumulated rate of Se by rye grass was the highest (40.24% ) at the earing stage.