Amino acid and amide metabolism in the hulls and seeds of developing fruits of garden pea, Pisum sativum L.

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SUMMARY

Pea plants (Pisum sativum L. cv. Melbourne Market), each with a single developing pod, were pulse-fed [4-14C]aspartate through the cut stem at stages from 11 to 32 d after full blossom. The distribution of radioactivity in soluble metabolites of the hull, seedcoats, embryo sac liquid and embryo was determined by 2-dimensional paper chromatography and radioautography after feeding intervals of 6 h, 24 h or 48 h. At the earliest stage, radioactivity was recovered mainly in sucrose, serine, homoserine and threonine in the hull. At the 15-16 d stage, threonine became the major derived amino compound secreted into the embryo sac, and sucrose became the predominant derivative recovered from both hull and seed tissues. Stem-fed aspartate can therefore be transferred to stem phloem, and sucrose synthesized from aspartate in stems and leaves can be transferred to phloem in both organs.

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