LEUCOCYANIDIN REDUCTASE-ACTIVITY AND ACCUMULATION OF PROANTHOCYANIDINS IN DEVELOPING LEGUME TISSUES

Proanthocyanidin (PA) and anthocyanin accumulation and location in dev eloping leaves, flowers, and seeds of the legumes Medicago saliva, Lot us japonicus, Lotus uliginosus, Hedysarum sulfuresens, and Robinia pse udacacia were investigated by quantitative measurements and by histolo gical analysis after staining with 1% vanillin/HCl, butanol/HCl, or 50 % HCl. M. saliva leaves and flowers, L. japonicus leaves, and R. pseud acacia flowers do not contain PAs, but seeds of all investigated speci es contain PAs. Anthocyanins are absent in the seed coats of all five species and in leaves of L. japonicus. PA content generally increases as a function of development in leaves, but declines in flowers. With the exception of H. sulfurescens, flower PAs are synthesized in the pa renchyma cells of the standard petal, while anthocyanins are located i n the neighboring epidermal cells. Leucocyanidin reductase (LCR) catal yzes the conversion of 2,3-trans-3,4-cis-leucocyanidin to (+)-catechin and is the first enzyme in the PA-specific pathway. LCR activity was only detected in PA-containing tissues and generally declined during t issue development.