Action de la lumière blanche et de quelques radiations monochromatiques sur la morphogenèse in vitro du Linum usitatissimum

Abstract

Bud neoformation from hypocotyl segments of flax grown in vitro was stimulated when the quantity of light was increased up to about 57.6 J cm−2 d−1 after which it remained almost unchanged. The spectral dependence for four wavelengths chosen in the visible range was similar to maximal absorption of chlorophyll, with one peak in blue light and another in red light. Photosynthesis by the mother plants, before excision, as well as by the explants was necessary for optimal neoformation of buds in hypocotyl segments. However, photosynthesis by the explant seemed to be the most conducive to shoot morphogenesis. A sucrose supplement could only partially replace photosynthesis before or after explant culture. The addition of amino acids and vitamins or organic acids with sucrose did not replace photosynthetic activity of the explants. A treatment with 3-(3,4-dichlorophenyl)-1,1-dimethylurea strongly reduced shoot formation, whereas 3-amino-1,2,4-triazole had no inhibitory effect.