Inhibition by Auxins of 4-Methyleneglutamic Acid Synthesis in Tissue Cultures of Peanut Seeds

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Abstract
Callus cultures of peanut (A. hypogaea L. cv Valencia Tennessee Red) cotyledons grown on Linsmaier and Skoog medium containing normal levels of auxin and cytokinin do not synthesize either 4-methyl-eneglutamic acid or 4-methyleneglutamine, nonprotein amino acids normally found in significant amounts in peanut plants. If mature peanut embryos (with cotyledons removed) are germinated and grown on a similar medium containing no added phytohormone, normal levels of these 2 amino acids accumulate. The addition of an auxin, however, prevents formation of 4-methyleneglutamic acid and 4-methyleneglutamine. Typical levels of other free amino acids are seen and excised embryos so cultured develop into apparently otherwise normal plants. Kinetin addition to embryo cultures has little or no effect. 4-Methyleneglutamine is formed when 4-methyleneglutamic acid is added to embryo cultures maintained on auxin-containing medium, indicating that the phytohormone does not block amidation but rather the biosynthesis of 4-methyleneglutamic acid.