Biorreator e luz natural na micropropagaÃÃo de abacaxizeiro / Bioreactors and natural light for pineapple micropropagation

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Commercial micropropagation is a restricted alternative because of the high costs of plantlets produced by this system. The objective of the present study was to evaluate news technologies for pineapple micropropagation. Culture medium used was composed by MS salts (Murashige &Skoog, 1962), with sucrose 30 g.L-1, pH adjusted to 5.8 before autoclaving at 1210C and 1 kg.cm-2 for 20 min. Growth regulator BAP (1.0 mg. L-1) with ANA (0.25 mg.L-1) were used for multiplication phase and ANA 0.25 mg.L-1 for in vitro rooting. Efficient mass propagation of pineapple plantlets was obtained with bioreactors, resulting in 19 shoots per explant and up to 190-200 plantlets in 1-Litre vessel after 45 days of culture. In the temporary immersion system, plantlets were immersed for 3 minutes every 2-h, with better results than the permanent immersion bioreactors. Natural light was another technique used to maintain in vitro micropropagated pineapple cultures, demonstrating better development during rooting phase. Plantlets cultured under natural light were taller, with a good rooting system growth and greater dry weight when compared with conventional micropropagation (artificial light). For the anatomical analysis, it was observed that the epidermis layer presented more thickness and the better organization. Also, chlorenchyma and water storage tissue showed better organization and higher stomata density when compared with conventional micropropagation. In vitro rooting under natural light provides better adaptability of plantlets in the acclimatization process with greater growth of aerial part, of roots and also the best dry weight accumulation. Leaves structures showed more thickness and better performance of ex vitro development, high irradiance provided by natural light was responsible for the plasticity obtained for the in vitro pineapple culture and also resulted in better responses in terms of adaptability after transference to the natural environment.

ASSUNTO(S)

propagaÃÃo peneapple abacaxi fitotecnia vegetal anatomy cultura de tecido anatomia vegetal tissue culture propagation

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