Isoxazolin-5-ones and Amino Acids in Root Exudates of Pea and Sweet Pea Seedlings

Seeds of Pisum sativum L. cv Finale and Lathyrus odoratus L. cv Spencer were germinated aseptically in moistened sand in the dark. At several stages, the amino acid composition of the exudate and of the corresponding roots was analyzed. A number of common amino acids, including homoserine, were exuded by the growing seedling root in an early stage and were partly reabsorbed later. A number of uncommon amino acids, including several isoxazolin-5-one derivatives, uracil alanines, l-gamma-glutamyl-d-alanine, and alpha-aminoadipic acid were exuded at different rates.