ANTHOCYANIN SYNTHESIS AND LENGTHENING IN THE 1ST LEAF OF BARLEY ISOGENIC LINES

Anthocyanin production and lengthening in relation to light, low temperatures and gibberellin (GA) effects are studied in the first leaf (blade and sheath) of four isogenic lines of barley (Hordeum vulgare L.) whose genotypes regarding GA-synthesis and GA-sensitivity are: MC20 = normal; MC96 = dwarf, lacks GA-synthesis but increases growth when its is supplied with GA; MC90 = semi-dwarf and GIGAS = giant, both synthesize GA but GA-supply does not modify their growth. Light was an essential factor for anthocyanin (cyanidin-3-monoglucoside) synthesis in blade and sheath of all four lines. Low temperatures promoted anthocyanin synthesis in blade and favoured it in sheath. Exogenous GA (GA3 = gibberellic acid) increased anthocyanin synthesis mainly in sheath. Blade and sheath differential behaviour might be due to a tissue compartmentalization. All four lines lacked chlorophyll when grown in darkness. However, the inhibition of leaf elongation in light compared to darkness (etiolation) was observed in MC20 but not in MC90 and GIGAS. The data obtained on the present barley isogenic lines indicated that light, supposedly through phytochrome activity, regulates both anthocyanin synthesis and growth by two different (independent?) mechanisms of action. © 1990.