Attempts were made to clarify N translocating forms from the rooting zone and vegetative parts to peanut fruits, and the possibility of oxidation of NH_4-N to NO_3-N in nodule. Peanut plants were allowed to grow in pots filled with vermiculite, to which no nitrogen (N-N treatment), NO_3-N as NaNO_3 (NO_3-N) or NH_4-N as (NH_4)_2SO_4 (NH_4-N treatment) was supplied. Results obtained are as follows : 1) In addition to the NO_3-N treatment, NO_3-N was found in nodules of the N-N and NH_4-N treatments, and the NO_3-N content of nodules was higher in the NH_4-N treatment than in the N-N treatment. These results suggest that NH_4-N is oxidized to NO_3-N in nodules of peanut plant. 2) In the xylem saps of every treatment, the asparagine (Asn) concentration was the highest in amino acid and amide (AA-N), whereas in bleeding saps from gynophores of every treatment, glutamine (Gln) was higher, following by Asn. In the peanut plant, it suggests that N is translocated as Asn from the rooting zone and as Gln from vegetative parts to fruits. 3) The facts that Gln contents of fruit in the NO_3-N and NH_4-N treatment were higher than that in the N-N treatment, indicate that inorganic N absorbed from the peanut shell is firstly incorporated into Gln.
