Effects of Nutrient Supply on Seed Growth of Field Bean (Vicia faba L.). 1. Effects of Different Sulphur and Methionine Regimes on Cotyledon Growth, Protein and Uncombined Amino Acids In vitro

Publisher Website
Google Scholar
Abstract
The effects of differemt S and methionine regimes on growth of developing Vicia faba cotyledons in vitro were studied. Basal medium (containing adequate S) supplemented with 0·5 mM methionine marginally increased d. wt and uncombined amino acid accumulation but adding 1–5 mM methionine inhibited both growth and protein accumulation. Sulphur deficiency reduced both d. wt and protein accumulation but incresed accumulation of uncombined amino acids. Adding 1 mM methionine to the S-deficient medium restored growth, normal protein and uncombined amino acid acnunulation. High sulphate medium (7.5 mM ) decreased d. wt, protein and uncombined amino acid accumulation. High sulphate medium or basal medium+methionine (0·5 mM) changed the proportions of the seed proteins; legumin increased but vicilin decreased. Sulphur deficiency caused a relative increase in vicilin but a decrease in legumin. The different S and methionine regimes markedly changed the composition of the uncombined amino acids, especially those derived from aspartic acid but not the composition of the protein fraction, except during S deficiency. The data presented indicates a flexibility in the storage protein composition of developing cotyledons grown in vitro, with the S and methionine status having a regulatory effect.