THE CONTENT OF N-MALONYL-D-TRYPTOPHAN IN WHEAT SEEDLINGS

N-Malonyl-D-tryptophan (MTry) and L-tryptophan (L-Try) were not found in dry wheat seeds, but appeared and accumulated during their germination. Seedlings of Triticum aestivum L. (all varieties studied) and T dicoccum L. contained MTry, whereas MTry was absent in seedlings of T monococcum L. More than 90% of total MTry of the seedling located in the coleoptile and remaining amount was found in roots. Maximum contents of MTry in coleoptiles was observed at the 6th day after imbibition. The illumination of seedlings caused inhibition of growth of the coleoptiles and retardation of MTry accumulation. Growth of wheat seedlings from isolated embryos on the Norstog's medium was greatly reduced as compared with the growth of seedlings from intact seeds. MTry was not found in seedlings grown from isolated embryos. Addition Of L-Try or D-Try into the medium resulted in the appearance of MTry in these seedlings, but their growth was not restored. It is assumed that MTry synthesis in wheat seedlings is regulated not only on the level of enzyme (racemase and N-malonyl-transferase) activity, but also on the level of substrate (L-Try) concentration.