SPECIFIC NUTRIENT-UPTAKE DURING INITIATION OF SOMATIC EMBRYOGENESIS IN COCONUT CALLUSES

Changes in the concentration of major nutrients and sugars in the media were measured for two embryogenic strains of coconut calluses, L1 and L7, after 0, 14, 28, 42 and 56 days of culturing on multiplication medium and embryogenesis induction medium. A histological study was made on day 0, 28 and 56. The initiation of somatic embryogenesis was achieved in these two strains through two different pathways: one (strain L1), of pluricellular origin, was obtained by decreasing the 2,4-D concentration in the medium, and the other (strain L7), of unicellular origin, by increasing the level of 2,4-D. In spite of these differences, both kinds of embryogenesis initiation were linked to specific requirements:higher uptake per g of dry matter of NH4+, Ca2+, Mg2+ and sucrose.