Photocontrol of Anthocyanin Synthesis

Abstract

Light-dependent anthocyanin synthesis is a typical high irradiance response (HIR) of plant photomorphogenesis. The spectral sensitivity of this response in young seedlings of cabbage and tomato is strongly affected by the length and mode of application of the Ught treatments. This observation suggests that the different experimental conditions, used in different action spectroscopy studies, might have been responsible, at least in part, for some of the reported differences in the characteristics of the HIR action spectra of different response-system combinations. In both cabbage and tomato, the values of the far red/blue, far red/red, and blue/red action ratios increase with increasing durations of the light treatments; this finding is in agreement with hypotheses of K. M. Hartmann (1966, 1967) and E. Schifer (1975) for phytoc trm action in the HIR. The similarity in the trend of change of the values of the action ratios suggests the possibility that the pbotomorphogenic pigment system, involved in the photoregulation of anthocyanin synthesis, may be the same in cabbage and tomato, even though there are some differences in the spectral sensitivity of the response between the two species.The measurement of action spectra is the first step taken toward the identification of the pigment system acting as the photoreceptor for a given photoresponse. The action spectroscopy studies of the HIR (high irradiance responses of plant photomorphogenesis whose full expression requires prolonged exposures to high irradiances of visible and near visible radiation) have shown that there are large differences in the spectral sensitivity of different response-system combinations (Fig. 4 9). Differences have been found in the wavelengths of the peaks of action and in the combinations and relative efficiencies of the effective spectral regions (1-3, 6, 7, 9, 13-16). As an example, consider the differences in the spectral sensitivity of anthocyanin synthesis in young seedlings: BL2 is the only effective region in sorghum (2); BL and FR are about equally effective in mustard (17); FR is more effective than BL in turnip (13); and BL is more effective than FR in tomato (11). The causes of these differences are still poorly understood and are partly responsible for the state of uncertainty about the nature of the HIR photoreceptor (9, 15).There are some points that are seldom mentioned when the data of the action spectroscopy studies are used in discussions 1 Research partially supported by a National Science Foundation Grant, PCM76-80932, to A. L. M.2 Abbreviations: BCJ: incandescent lamps with an integral dark red filter, having a cut-off at about 650 nm; BL: blue; R: red; FR: far red; W: white; HIR: high irradiance response; P: total phytochrome = Pr + Pfr, TD: total duration of exposure.about the possible identity of the HIR photoreceptor. (a) The experimental conditions (length, irradiance and mode of application of the light treatments, temperature, age of the system) used in different studies vary quite widely, as shown...

The Photoregulation of Anthocyanin Synthesis

“…For most of the systems, assigned to group I, FR and BL are the most effective regions. For tomato and rye seedlings (MANCI-NELLI 1981, MANCINELLI and WALSH 1979, RABINO et al 1977, the UV jBL region is much more effective than the Rand FR ones.…”

“…Examples: seedlings of white mustard (KANDELER 1958, MOHR 1957, WAGNER and MOHR 1966, black mustard (KANDELER 1958), leaf mustard (KANDELER 1958), red cabbage (KANDELER 1958, Ku-TAI 1972, Ku and MANCINELLI 1972, MANCINELLI and WALSH 1979, RABINO et aI. 1977, SIEGELMAN and HENDRICKS 1957, tomato WALSH 1979, RABINO et aI.…”

“…The results of some studies indicate very clearly that the spectral sensitivity of anthocyanin production under continuous irradiation can be markedly affected by duration and fluence rate of the exposure, age and state of etiolation or de-etiolation of the system, temperature and nutritional conditions (ALFER-MANN 1972, GRILL 1967, Ku-TAI 1972, MANCINELLI 1981, MANCINELLI and WALSH 1979, RABINO et al 1977, WAGNER and MOHR 1966. The data of Table 1 give an idea of the effect of the experimental conditions upon the spectral sensitivity of anthocyanin production in various systems.…”

Interaction between Light Quality and Light Quantity in the Photoregulation of Anthocyanin Production

“…Previous studies in my laboratory (10,16) have shown that the R/FR effectiveness ratio for anthocyanin production under continuous irradiation can be significantly affected by the duration and the photon flux ofthe light treatments. However, specific studies on the relationships between the state of phytochrome, as defined by X and H, and anthocyanin production, under continuous light treatments, at values of 4 different than those established by R and FR, had not been carried out.…”

“…However, specific studies on the relationships between the state of phytochrome, as defined by X and H, and anthocyanin production, under continuous light treatments, at values of 4 different than those established by R and FR, had not been carried out. The purpose of this study was to determine the extent of the differences in the pattern of interaction between light quality and quantity on phytochrome-mediated anthocyanin production in the seedlings of two species, Brassica oleracea L. and Lycopersicon esculentum Mill., which show large differences in the sensitivity of the response to R and FR (10,16,20). Anthocyanin production in both species shows a marked response to BL, which is mediated by cryptochrome (21 92,1990 of streptomycin (200 ,ug/mL; 8 mL per dish) and were incubated in darkness until the beginning of the light treatments, which started 4 d after sowing.…”