Anthocyanin Synthesis in Corn Endosperm Tissue Cultures. II. Effect of Certain Inhibitory and Stimulatory Agents

Abstract

In a previous paper (7), the advantages of corn endosperm tissue cultures as an experimental tool in attacking the problem of anthocyanin synthesis were pointed out. The general culture conditions, the identity of the pigments, and the requirement for light were reported in the same paper.Thimann and Radner (11,12) have shown that anthocyanin synthesis in Spirodela is inhibited by -purine and pyrimidine antagonists, by certain sulfurcontaining compounds and certain amino acids. They also demonstrated (13) that riboflavine reverses the inhibition caused by many of these substances, and further that riboflavine substitutes for the light reaction involved in anthocyanin production by Spirodela.When work on the current problem was begun, it was expected that the effect of various chemicals on anthocyanin synthesis in both the endosperm cultures and Spirodela would prove to be similar. As this report will indicate, however, data obtained so far show that pigment synthesis in the two systems is affected differently by certain of the same compounds tested. MATERIALS AND METHODSTissue cultures derived from endosperm of the corn variety, Black Mexican Sweet, were used in this study. The method of preparing the explants, general culture conditions, and determinations of weight and pigment concentration have been described previously (7). The culture medium used in the present study has been modified from that used in the previous investigation. Tissues were analyzed 25 days after transfer to the experimental media.Originally the medium contained 0.5 % Seitzfiltered yeast extract. In some of the experiments described here, the yeast extract was omitted and in its stead 0.2 % casein hydrolyzate (acid-hydrolyzed, vitamin-free) adjusted to pH 6.6 with KOH was substituted. In other experiments, asparagine at a concentration of 1.5 x 10-2 M was substituted for the yeast extract.

Chemical Factors Affecting Anthocyanin Formation and Morphogenesis in Cultured Hypocotyl Segments of Impatiens balsamina

“…When used in combination with benzimidazole in the light, riboflavin severely inhibited all activities of the hypocotyl and was lethal to most of the lower segments. In agreement with our results, Straus (9) has shown that riboflavin inhibited anthocyanin synthesis in cultured corn endosperm tissue.…”

“…The relationship between the level of differentiation of a tissue and the sensitivity of anthocyanin synthesis to 8-azaguanine was further supported by the observation that the anthocyanin was formed well up into the hypocotyl arch (meristematic region) when 8-azaguanine was present in the medium. Straus has reported that 8-azaguanine caused a slight enhancement of anthocyanin formation in cultured corn endosperm tissue (9). The corn endosperm seems to approximate more nearly the condition of the meristematic tissue of segment 1 than the mature Spirodela plants used by Thimann et al (10)(11)(12)(13).…”

Physiology and Functions of Flavonoids

“…Bibb and Hagen, 1972;Creasy et al , 1965;Hartmann, 1970;Hess, 1966;Longevialle, 1969;Margna etal., 1969;Mohr and Bienger, 1967;Mohrand Senf, 1966;Rossiter and Barrett, 1970;Straus, 1960). Inhibitors of protein synthesis may block the accumulation of one flavonoid, but not another, in the same tissue.…”

Inhibition of anthocyanin synthesis in the first internode of Sorghum bicolor by cobaltous ions. The site of action of cobalt

“…Glutathione also promoted anthocyanin synthesis and PAL activity in internode segments not treated with Co'* (Tab, 2), while cysteine showed no such effect (Tab, 3), Glutamic acid promotes anthocyanin synthesis in tissue cultures derived from corn endosperms (Straus 1960), Glutathione contains a glutamyl side-chain which might play a certain role during anthocyanin synthesis, NEM, a sulfhydryl reagent, bad no effect on anthocyanin synthesis and PAL activity at low concentrations but at 0,1 mM and 1 mM it inhibited both processes up to 47% and 70%, respectively (Fig, 2), Addition of 1 mM cysteine or glutathione alleviated the inhibitory effect of NEM in the internode segments (Tab, 4), These results further show involvement of sulfhydryl groups in anthocyanin synthesis.…”