Propagação vegetativa de aroeira schinus terebinthifolius Raddi Canela Sassafras Ocotea pretiosa Benth & Hook e cedro Cedrela fissilis Vellozo atraves de estacas radicais e caulinares

Abstract

A presente pesquisa teve a finalidade de avaliar o enraizamento de estacas radiciais e caulinares de três espécies florestais nativas: aroeira [ Schinus terebinthlfolius Raddi); canela sassafrás [ Ocotea pretiosa Benth & Rook); e cedro [Cedrela fissilis Vellozo), agrupadas em três classes diamétricas, em condições de viveiro parcialmente controladas de telado, sombrite 501., ap6s tratamentos com promotores do enraizamento. Os testes foram realizados em duas épocas do ano [outono/inverno e primavera/verão) e observados durante 4 meses. As estacas foram cortadas nas seguintes dimensões: 10 cm de comprimento e 0.4 a 3.2 cm de diâmetro e com 20 cm de comprimento e 0.4 a 2.4 cm de diâmetro, respectivamente para as estacas radiciais e caulinares. As estacas foram tratadas com acido indol-butírico [AIE] e ácido naftaleno-acetico [ANA), na forma de pó em três dosagens 500, 1000 e 1500 ppm. O substrato utilizado foi um composto de vermiculita, areia grossa peneirada e terra preta peneirada na proporções 2:2:1. Os tratamentos auxínicos [AIS e ANA] não apresentaram resultados satlsfat6rlos em todos os testes realizados. Os sub-tratamentos, que são as estacas de diâmetros distintos [fino, médio e grosso) tiveram resultados satisfat6rlos. As estacas radiciais de aroeira plantadas na época do outono não brotaram e nem enraizaram; as caulinares finas, médias e grossas tiveram uma sobrevivência média de 42.9%, 66.7%, 52.3%, respectivamente. O melhor percentual de enraizamento [23.8%], foi conseguido com as estacas de diâmetro médio. Na época da primavera/verão, as estacas caulinares finas de aroeira apresentaram enraizamento de 4.8%, médias 19.1% e grossas 21.3%. As estacas radiciais de canela sassafrás no outono/inverno não brotaram e nem enraizaram, mas mesmo assim permaneceram vivas. As caulinares finas, medias e grossas apresentaram somente brotações, 23.8%, 23.8%. e 28.6%. respectivamente. Já na época da primavera/verão, as estacas caulinares de canela sassafrás brotaram com os seguintes percentuais 0%, 28.6% e 52.4%, porem não houve enraizamento. Estacas radiciais finas, médias e grossas de cedro no inverno tiveram enraizamento, de 4.7%, 14.3% e 47.6%. Já as caulinares apresentaram um percentual de enraizamento de 23.8%, 52.4%, 33.3%. Na primavera/verão, as estacas caulinares de cedro não enraizaram, chegando aos 60 das com 100% de mortalidade. Portanto, conclui-se que, o cedro tem multiplicação satisfatória através de estaquia, sendo a melhor época para enraizamento de suas estacas o final de outono ou inverno. Os melhores melhores resultados para a espécie foram obtidos com estacas radiciais de diâmetros entre 2.1 e 3.2 cm e caulinares entre 0.8 e 1. 3 cm.

A study was developed in order to evaluate the rooting capabilities of cuttings obtained from the root system as well as from the aerial system of three Brazilian native forest tree species: "Aroeira" (Scinus terenbinthifolius Raddi), "Canela sassafras" (Ocotea pretioea Benth&Hook), and "Cedro" (Cedrella fissilie Vellozo). After the rooting inducing treatments were applied, all cuttings were classified into three diameter classes and planted in a nursery with partiallycontroled local conditions (a 50% shade was provided). Subsequent tests were performed in two different occasions of the year (Autumm/Winter and Spring/Summer) and results were evaluated during the following four months, respectively. For all species, the cuttings were prepared according to the following dimensions: a) root cuttings: 10 cm length and diameter ranging from 0.4 to 3.2 cm, and b) aerial cuttings: 20 cm length and diameter from 0.4 to 2.4 cm. Major treatments were the use of indol-butiric acid (AIB) and naftalen-acetic acid (ANA), as a powder. in three different dosages: 500, 1000 and 1500 ppm. A composite substratum prepared with vermiculite, coarse sand and organic soil in a 2:2:1 proportion was used. The hormone treatments (AlB and ANA) did not produce satisfactory results for all tests performed. The subtreatments, i.e. the three diameter classes (cuttings of small. average and large diameters) produced satisfactory results. The root cuttings of "Aroeira" planted in Autumm, did not produceneither roots or leaves at all. On the other hand, for the same species, the aerial cutings, with small average and large diameters, had a survival rate of 42.9%. 66.7% and 53.3% respectively. For that species the best rooting percentage (23.8%) was obtained with the average diameter cuttings and for the Spring/Summer test the aerial cuttings had rooting percentages of 4.8% (small diameter) and 19.1% ( average diameter) and 21.3% (large diameter). The Sassafras root cuttings did not produce any root or leave in Autumm/Winter, but remained alive anyway. For this species, the small, averageand large diameter aerial cuttings produced only leaves, 23.8%, 23.8%, and 28.6%, respectively. For the Spring/Summer test, the Canela Sassafras aerial cuttings produced leaves according to the following rates: 0%, 28.6% and 52.4%, respectively. In this treatment, however, no rooting was observed at all. For Cedro, root cuttings of small, average and large diameters, planted in Winter. had a 4.7%, 14.3% and 47.6% rooting percentage. For this last species, and in the same diameter classes ranking,rooting percentages were 23.8%. 62.4% and 33.3%. For the Spring/Summer test, the aerial cuttings of Cedro did not produce any root. reaching the 60th day with 100% mortality. From the whole study, it was concluded that Cedro had a satisfactory vegetative propagation capability. For this species the end of Autumm/Winter is the best time of the year for the rooting. Concerning cutting diameters for Cedro, best results were obtained as follows: for root cuttings between 2.1 and 3.2 cm, and for aerial cuttings between 0.8 and 1.3 cm.