Anthocyanin production in chl-rich and chl-poor seedlings.

Screening by chlorophyll (Chl) affects photoconversion rates and photoequilibrium ratios of phytochrome in vivo and may cause distortion of the action spectra of photomorphogenesis (N Kazarinova-Fukshansky, M Seyfried, E Schäfer 1985 Photochem Photobiol 41: 689-702). Inhibitors that reduce the Chl content of seedlings are sometimes used in photomorphogenesis research to decrease the effects of Chl screening on the state of phytochrome in vivo. Streptomycin is one of the inhibitors that can be used for this purpose. The effects of streptomycin on phytochrome-mediated anthocyanin accumulation in young seedlings are significantly different in closely related systems. The use of ;Chl-bleachers' in photomorphogenesis studies may produce undesirable side effects. At the level of the expression of a photoregulated response, the effects of differences in the state of phytochrome between water-grown Chl-rich and inhibitor-treated Chl-poor seedlings may be difficult to evaluate because they may be masked by the effects of the inhibitor on the response.