The addition of Se at 0, 1 and 2.5 ppm to the cowpea plants (Vigna sinensis) in the form of Na2 SeO3. 5H2O affected bound aminoacids in plants which formed about 1/3 of the total dry matter of normal cowpea plants and isoleucine about 1/3 of the total aminoacids. Tyrosine was in the lowest amount. At 2.5 ppm Se, free aminoacids were greater than at 1 ppm Se and in the normal plants free aminoacids were about 2 per cent of total aminoacids.
Aminoacids in bound and free state behaved differently at the increasing Se levels. In bound form, tyrosine and phenylalanin were found absent at 2.5 ppm Se, while threonine, serine, p roline and glycine showed an increase at 1 ppm Se than control, which at the higher concentration decreased. Cysteine, Valine, Methionine, Isoleucine and Arginine were not found in the free form and Lysine and Histidine were in traces. Selenium at 1 ppm greatly inhibited the free aminoacids content but at 2.5 ppm free aminoacids were higher than 1 ppm.
