Acta Scientiarum: Agronomy (Jan 2010)
Níveis de ácido indol butírico (AIB) no enraizamento in vitro de microestacas de mamoeiro ‘Tainung 01’ = Indole butyric acid (IBA) levels in the in vitro rooting of microcuttings of papaya tree ‘Tainung 01’
Abstract
Este trabalho teve como objetivo avaliar níveis de AIB no enraizamento in vitro de microestacas de mamoeiro (Carica papaya L. ‘Tainung 01’). Ápices caulinares de plantas com 120 dias de idade foram estabelecidos e avaliados em meio MS, suplementado comcomplementos orgânicos constituídos de sacarose a 87,64 mM, mio-inositol a 555,06 μM, tiamina-HCl a 0,30 μM, piridoxina-HCl a 2,43 μM, ácido nicotínico a 4,06 μM e 0; 0,74; 1,48; 2,96 e 5,92 μM de AIB, em delineamento inteiramente casualizado, com quatro repetições e cinco tubos de ensaio por parcela. Após 30 dias, avaliou-se a percentagem de enraizamento, o crescimento das microestacas, o comprimento da maior folha e a massa de calo. Observou-se que o maior percentual estimado de enraizamento ocorreu com a adição de 5,92 μM no meio de cultivo. Apesar do maior crescimento das microestacas e da maior folha ocorrer em níveis de AIB superiores a 0,74 μM, ocorre, concomitantemente, maior formação de calos na base das microestacas e muitas das raízes são provenientes desses calos, as quais não possuem conexões com o sistema vascular dos ramos. The objective of this work was to test IBA levels in the in vitrorooting of microcuttings of papaya tree (Carica papaya L. 'Tainung 01'). Apical stems of plants at 120 days of age were established and evaluated onto MS supplemented medium with organic complements constituted of sucrose at 87.64 mM, myo-inositol at 555.06 μM, thiamin-HCl at 0.30 μM, pyridoxine-HCl at 2.43 μM, nicotinic acid at 4.06 μM and treated with 0, 0.74, 1.48, 2.96 and 5.92 μM of IBA, in a completely randomized design, with four replications. After 30 days, the percentage of rooted microcuttings, the development of microcuttings, the length of the largest leaf and callus mass were evaluated. It was observed that the largest percentage of rooting happens in the presence of IBA at 5.92 μM during of cultivation. In spite of the fact that larger growth of microcuttings and the largest leaf happened in levels above 0.74 μM of IBA, a larger formation of calluses happens concomitantly in the microcuttings and many of the roots are coming from those calluses, which do not possess connections with the vascular system of the shoots.
