Tropicultura (Jan 2008)
Régénération in vitro et caractérisation physiologique de variants somaclonaux de glaiëul (Gladiolus grandiflorus Hort.) tolérants aux basses températures
Abstract
In vitro Regeneration and Physiological Characterization of Gladiolus (Gladiolus grandiflorus Hort.) Somaclonal Variants Tolerant to Low Temperatures. In order to regenerate new clones of Gladiolus (Gladiolus grandiflorus Hort.) more tolerant to winter cold, somaclonal variation was undertaken in vitro through callus culture technique combined with low temperature selective pressure and/or gamma rays irradiations (cobalt 60). Amongst the 5 somaclones (R1, Rb1, Rb2, Rib1, Rib2), variant R1 was regenerated at 23 °C and then selected after culture at 8 °C, Rb1 and Rb2 were regenerated at 8 °C, Rib1 and Rib2 came from callus irradiated with cobalt at 20 and 40 gamma rays and cultivated at 8 °C. Low temperature tolerance was measured by the chlorophyll content, the chlorophyll fluorescence and the photosynthesis. Low temperature did not affect R1, Rb1, Rb2 and Rib1 somaclones while the control (T) and Rb2 were susceptible. In fact, initial fluorescence (F0) was high in the last two genotypes and the Fv/Fm ratio, photosynthetic efficiency indicator, was affected. A positive relation was found between the photosynthesis rate and the Fv/Fm ratio and between the photosynthesis and leaf chlorophyll content.
