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Conversion of D‐tryptophan to indole‐3‐acetic acid in coleoptiles of a normal and a semi‐dwarf barley ( Hordeum vulgare ) strain
Author(s) -
Tsurusaki Kenichi,
Watanabe Sachiko,
Sakurai Naoki,
Kuraishi Susumu
Publication year - 1990
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1990.tb06733.x
Subject(s) - coleoptile , hordeum vulgare , tryptophan , strain (injury) , endogeny , biology , indole 3 acetic acid , biochemistry , elongation , poaceae , botany , auxin , amino acid , gene , anatomy , ultimate tensile strength , metallurgy , materials science
Exogenously applied D‐tryptophan (D‐Trp) was more effective than L‐Trp in inducing elongation of coleoptile segments of a normal barley ( Hordeum vulgare L. cv. Akashinriki) strain and a semi‐dwarf strain with lower endogenous indole‐3‐acetic acid (IAA) level. D‐cycloserine, an inhibitor of D‐aminotransferase, completely inhibited both the D‐ and L‐Trp‐induced elongation of both strains. Addition of D‐Trp increased IAA levels in both strains 4‐fold over endogenous levels. The increase in IAA level was completely inhibited by D‐cycloserine. The endogenous L‐Trp level of semi‐dwarf coleoptiles was similar to that of normal ones. These results suggested that IAA is synthesized by the conversion of L‐Trp to indole‐3‐pyruvic acid via D‐Trp in both strains, and that the lower IAA level of the semi‐dwarf strain probably is a result of the impeded IAA biosynthesis involved in D‐Trp.