MICROPROPAGATION OF EUCALYPTUS SALIGNA SM. FROM COTYLEDONARY NODES

Abstract

Eucalyptus saligna is an important woody plant used to lumber and cellulose. The aim of this research was to establish a protocol for micropropagation of this species from cotyledonary nodes. Plantlets with 16 days old were used as a donor explants. The induction of cotyledonary nodes consisted of two parts: a dark culture followed by a light culture. Basal medium was MS added with 30g.L-1 sucrose, 10% coconut water and solidified with 7g.L-1 agar. For the dark culture the media were supplemented with 3.6μM NAA (Naftalenoacetic acid) and 4.4 μM BAP (6-Benzylaminopurine) and for the light culture the media were supplemented with 2.7μM NAA and 1.1 μM BAP. The period for dark and light culture was 20 days. Shoots were multiplied on MS medium, 30 g.L-1 sucrose supplemented with 1.1 μM BAP. Shoots were elongated on MS medium free of plant growth regulators. Shoots were rooting on half-strength MS salts. Acclimatization was performed in a hydroponics floating system. Moreover, the shoot multiplication in liquid medium with different CaCl2 levels was carried out under agitation. Organogenesis of cotyledonary nodes was characterized by simultaneous occurrence of shoot and callus. Shoots presented hyperhydricity under liquid medium, however, the CaCl2 reduces the hyperhydricity in liquid medium; nevertheless, it had been not effective in eliminating hyperhydricity due to toxicity of chlorine. The hydroponics acclimatization results in 90% plant survival. An efficient protocol for micropropagation of E. saligna was suitable established and can be used for clonal propagation or genetic transformation.