Dynamics of adventitious rooting in mini-cuttings of Eucalyptus benthamii x Eucalyptus dunnii

Abstract

ABSTRACT.It is possible to determine the optimum time for permanence of vegetative propagules (mini-cuttings) inside a greenhouse for rooting, and this value can be used to optimize the structure of the nursery. The aim of this study was to determine the dynamics of adventitious rooting in mini-cuttings of three clones of Eucalyptus benthamii x Eucalyptus dunnii. Sprouts of H12, H19 and H20 clones were collected from mini-stumps that were planted in gutters containing sand and grown in a semi-hydroponic system. The basal region of the mini-cuttings was immersed in 2,000 mg L -1 indole-3-butyric acid (IBA) solution for 10 seconds. The rooting percentage of the mini-cuttings, the total length of the root system and the rooting rate per mini-cutting were also evaluated at 0 (time of planting), 7, 14, 21, 28, 35, 42, 49 and 56 days. We used logistic and exponential regression to mathematically model the speed of rhizogenesis. The rooting percentage was best represented as a logistic model, and the total length of the root system was best represented as an exponential model. The clones had different speeds of adventitious rooting. The optimum time for permanence of the mini-cuttings inside the greenhouse for rooting was between 35 and 42 days, and varied depending on the genetic material.Keywords: vegetative propagation, clonal forestry, organogenesis, mathematical modeling, rhizogenesis, clonal mini-garden. Dinamica de enraizamento adventício em miniestacas de Eucalyptus benthamii x Eucalyptus dunniiRESUMO. O tempo ideal de permanência de propágulos vegetativos (miniestacas) no interior da casa de vegetação para a rizogênese é possível de ser determinado matematicamente, o que pode otimizar as instalações do viveiro. O objetivo deste estudo foi determinar a dinâmica de enraizamento de miniestacas de três clones de Eucalyptus benthamii x Eucalyptus dunnii. Brotações dos clones H19, H12 e H20 foram coletadas de minicepas plantadas em canaletão com areia e cultivadas sob sistema semi-hidropônico. A região basal da miniestaca foi imersa em solução de 2.000 mg L -1 de ácido indolbutírico (AIB) por 10 segundos. A porcentagem de enraizamento de miniestacas, o comprimento total de raízes e a taxa de enraizamento por miniestaca foram avaliados a cada sete dias (0 -instante da estaquia, 14, 21, 28, 35, 42, 49 e 56 dias). Foram utilizadas as regressões logística e exponencial para a modelagem matemática da velocidade dos processos rizogênicos. O modelo logístico teve o melhor ajuste para o percentual de enraizamento, e o modelo exponencial para o comprimento total do sistema radicular. Os clones apresentaram diferentes velocidades de enraizamento. O tempo ideal de permanência das miniestacas dentro da casa de vegetação para o enraizamento está entre 35 a 42 dias, podendo variar em função do material genético.Palavras-chave: propagação vegetativa, silvicultural clonal, organogênese, modelagem matemática, rizogênese, minijardim clonal.

Stem Anatomy and Adventitious Root Formation in Cuttings of Angophora, Corymbia and Eucalyptus

“…Eucalypt cuttings are often harvested from either apical or sub-apical positions, or both, on the shoots of stock plants, with the position depending on the stock plant system, the frequency of cutting collection, the species, and the developmental phase of the shoot tips [3,5,7,9,17,[37][38][39][40][41]. Eucalypt cuttings, therefore, may have either a four-pointed stellate or rectangular shape in cross-section.…”

EX VITRO SYSTEM FOR Acer palmatum PLANTS PROPAGATION BY MINI-CUTTINGS TECHNIQUE

“…The mini-cuttings technique is similar to microcuttings technique (BRONDANI et al, 2012) and, compared to cutting, has some advantages such as reduction in the size of the propagules, increase shoots productivity per area, better rooting, often without the need of plant regulators STUEPP et al, 2015). It has been successfully used in the propagation of selected clones of different species WENDLING et al, 2010;STUEPP et al, 2016), applied with great frequency in the Eucalyptus propagation in Brazil (BRONDANI et al, 2012).…”

<b>Successive mini-cuttings collection in <i>Piptocarpha angustifolia</i> mini-stumps: effects on maturation, adventitious root induction and root vigor

“…The productivity of mini-stumps is a reflection of the adopted management and nutrition system. A semi-hydroponic system in sand, such as the one used in this study, was evaluated in previous studies with good results for P. angustifolia (Ferriani et al, 2011) and for several species of the Eucalyptus genus (Wendling et al, 2007;Da Cunha et al, 2009;Brondani et al, 2012aBrondani et al, , 2012c. The methodology of selective collection and nutritional management of mini-stumps proved to be effective and had little variation among collections made in the same season.…”

“…The methodology of selective collection and nutritional management of mini-stumps proved to be effective and had little variation among collections made in the same season. This system is a common variation in minicutting techniques (Brondani et al, 2012c) and has been linked to the physiological effect of ministumps, which indicates a greater or lesser recovery capacity under the influence of successive collections (Brondani et al, 2012a).…”