We investigated the composition of free amino acids in walnut (Juglans regia L.) seeds (embryo and cotyledons). We also examined xylem transport of free aminoacids in young seedlings grown in the absence of external nutrients (nitrogen autotrophyc growth). A relatively high concentration of free alanine was found in seed tissue, whereas a relatively high concentration of citrulline was detected in young seedlings. Citrulline is the main free amino acid trasported in the xylem to stem and leaves. The negligible presence of citrulline a non-protein amino acid, in the kernel and its presence at high concentration in all the tissues of young seedlings, including cotyledons, embryonic axis, tap root and stem, suggest that citrulline is synthesized during walnut germination. We conclude that citrulline plays an important role in nitrogen translocation during walnut germination.
Free amino acids in walnut kernels and young seedlings
Mapelli S;Brambilla I;Bertani;
2001
Abstract
We investigated the composition of free amino acids in walnut (Juglans regia L.) seeds (embryo and cotyledons). We also examined xylem transport of free aminoacids in young seedlings grown in the absence of external nutrients (nitrogen autotrophyc growth). A relatively high concentration of free alanine was found in seed tissue, whereas a relatively high concentration of citrulline was detected in young seedlings. Citrulline is the main free amino acid trasported in the xylem to stem and leaves. The negligible presence of citrulline a non-protein amino acid, in the kernel and its presence at high concentration in all the tissues of young seedlings, including cotyledons, embryonic axis, tap root and stem, suggest that citrulline is synthesized during walnut germination. We conclude that citrulline plays an important role in nitrogen translocation during walnut germination.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
