Ilex paraguariensis é uma espécie florestal que apresenta múltiplas potencialidades, sendo utilizada na indústria alimentícia, farmacêutica e cosmética. Contudo, a propagação seminal da espécie é limitada devido à baixa (inferior a 20%) e desuniforme germinação, além do longo período de estratificação das sementes (de quatro a seis meses) necessário para a quebra da dormência embrionária. Diante do potencial uso da miniestaquia como técnica alternativa para superar tais limitações, objetivou-se avaliar o efeito do ácido indolbutírico (IBA) no enraizamento de miniestacas de erva-mate coletadas nas quatro épocas do ano (de julho/2014 a maio/2015). As miniestacas foram confeccionadas com 6 cm (± 1 cm) de comprimento e duas folhas reduzidas à metade e, a porção basal dos propágulos foi imersa durante 10 segundos em diferentes soluções hidroalcoólicas de ácido indolbutírico (0, 2000, 4000, 6000 e 8000 mg L-1). Após 90 dias da permanência do material vegetal em casa de vegetação climatizada, foram avaliados: porcentagem de enraizamento, número de raízes e comprimento médio das três maiores raízes/miniestaca, porcentagem de calogênese, retenção foliar, brotações desenvolvidas e mortalidade. A primavera foi a época mais promissora, proporcionando aproximadamente 70% de enraizamento e, aliada à aplicação de 8000 mg L-1 de IBA, as miniestacas atingiram o maior comprimento (4,3 cm) e número de raízes (9,1) bem como, a menor taxa de calogênese (0%). A coleta das miniestacas na primavera e a aplicação de 8000 mg L-1 de IBA é a mais indicada para miniestaquia de erva-mate.

We aimed to evaluate the rooting potential of Tibouchina sellowiana through the experiments: I - Cuttings from current-year shoots and epicormic shoots were submitted to IBA concentrations: 0, 500, 1000, 1500 and 2000mg L-1, in a factorial arrangement 2 x 5 (two types of cuttings x five IBA concentrations), with four replicates and 20 cuttings each; II - mini-stumps of Tibouchina sellowiana were submitted to successive shoots collecting during the four seasons, in a split-plot design, with five replications of ten mini-stumps per experimental unit. From the shoots of mini-stumps, mini-cuttings were produced, which were initially kept in greenhouse and later transferred to full sun, in a 4 x 5 factorial arrangement (four seasons x five collections per season), with four replicates of 12 mini-cuttings. Superiority of epicormic shoots cuttings was reported when compared to the current-year shoots, which showed the highest rooting and leaves maintenance (42.50% and 55.00%, respectively), eliminating the use of IBA. High survival of mini-stumps (over 80%) and the mini-cuttings production (170mini-cuttings m-2 month-1) in clonal mini-garden and the mini-cuttings survival (above 80%) in the greenhouse demonstrated the technical feasibility, with summer as the most appropriate time to collect mini-cuttings.

RESUMO Genipa americana (jenipapeiro) é uma essência

In vitro germination and acclimatization of cambui tree type seedlings.Ciência Rural, v.44, n.8, ago, 2014. 1355In vitro germination and acclimatization of cambui tree type seedlings

To improve the production process of Aegiphila brachiata cuttings, the objective of this study was to evaluate the rhizogenic potential of cuttings from rejuvenated and adult mother plants collected in different seasons; we also characterized anatomically the cutting base, analyzed phenolic compounds and proteins contents, and identified polar metabolites. Two rooting experiments were carried out with cuttings from rejuvenated and adult mother plants, both collected in the four seasons of the year, submitted to treatments with indole butyric acid (0, 2000, 4000, 6000, and 8000 mg L− 1 IBA), and kept in a greenhouse for 45 days. The experimental design was completely randomized in a double factorial scheme for cutting experiments (5 [IBA] x 4 seasons), and for biochemical analyses (2 mother plants x 4 seasons, material collected in the moment of rooting experiment installation and after 45 days); for metabolomic characterization, the 2 mother plants were evaluated only at summer experiment installation. Propagules from rejuvenated mother plants collected in the spring are more viable and indicated to produce A. brachiata cuttings (25.25% rooting), not requiring the use of IBA. Despite the higher rooting rate of cuttings from rejuvenated mother plants, there are no anatomical differences from adult mother plants cuttings. The highest contents ​​of phenolic compounds were observed in propagules from rejuvenated mother plants in spring, indicating a positive effect of these compounds on the rhizogenic process. Maleic acid, 2-hydroxy-glutaric acid, mannose-6-phosphate, ribonic acid, glycine, and phosphoric acid were found in higher concentrations in cuttings from rejuvenated mother plants, with possible beneficial physiological effects on cuttings rooting.

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