<i>IN VITRO</i> CULTURE OF WHEAT TISSUES. II. MORPHOLOGICAL, CYTOLOGICAL AND ENZYMATIC VARIATIONS INDUCED IN WHEAT CALLUS BY GROWTH REGULATORS, ADENINE SALFATE AND CASEIN HYDROLYSATE

Abstract

Some morphological, cytological and biochemical characteristics of the calluses, derived from tetra- and hexaploid wheat, which were grown on various media, were investigated.Morphological characteristics: The calluses derived from the two wheat species did not differ in morphology from each other, but growth regulators, in a broad sense, caused great variation. The 2, 4-D, kenetin and adenine sulfate gave a smooth callus, casein hydrolysate produced a congregated globular callus, and IAA and NAA caused root development. Variations in the chromosome number of callus cells did not differ due to the differences in the media used and in the length of the subculture.Esterase zymogram: Esterase zymograms were analyzed by the gel iso-electro-focusing method. Zymograms of one, four and six days old seedlings after germination differed from each other. Zymograms of calluses which had been subcultured two or three times, became stable and uniform. When 2, 4-D was added to the medium, a callus-specific band appeared four days after germination; that is, one day earlier than the histological change of the root induced by 2, 4-D. Casein hydrolysate caused the instability of band 6 (at pI 6.5) in calluses derived from both wheat species.Protein profile: Seed protein from T. dicoccum had more acidic fractions than did T. aestivum. Protein profiles of leaves, roots and calluses did not differ between T. dicoccum and T. aestivum. Callus closely resembled roots in this regard.Amino acid composition of protein: The amino acid composition of protein and free amino acid were analyzed with seeds, calluses grown on different media. Seeds of T. aestivum cv. Chinese Spring showed a higher content of cystine than did T. dicoccum cv. Hokudai. The calluses of Chinese Spring (D callus) grown on a medium with a high concentration of 2, 4-D showed a larger amount of glutamic acid than those grown on the other media. In contrast, the contents of aspartic and glutamic acid decreased when casein hydrolysate was added to the medium. The amounts of amino acids were decreased by the supplement of casein hydrolysate. No cystine could be detected in any callus.