Ivar Wendling

Maturation and related aspects in clonal forestry – Part II: reinvigoration, rejuvenation and juvenility maintenance

Several techniques have been developed for reinvigorating, rejuvenating or maintaining the juvenility of plants. None of these techniques is as effective as natural rejuvenation whereby the most mature plant parts, the reproductive organs, produce the most juvenile plant parts, the embryos, through gametogenesis and sexual reproduction. The most common criteria for identifying reinvigoration or rejuvenation are based on morphology, morphogenic capacity and the ability to produce cones or flowers. Doubts remain over whether true rejuvenation (reduced ontogenetic age) can be achieved by artificial methods such as serial vegetative propagation, or whether these methods merely provide reinvigoration (reduced physiological age) by temporarily removing environmental and physiological constraints to growth. Rejuvenation and reinvigoration are difficult to distinguish from each other but there is some evidence that artificial methods provide at least partial rejuvenation of plants. This review examines methods for delaying the maturation of juvenile plants and for reducing the ontogenetic or physiological age of more-mature plants. The review discusses theoretical and practical aspects of juvenility, rejuvenation and reinvigoration in clonal forestry, and identifies research areas in maturation that could lead to more-effective methods for establishing high-productivity plantations.

Maturation and related aspects in clonal forestry—Part I: concepts, regulation and consequences of phase change

Progression from the juvenile to mature phase in woody plants is accompanied by changes in characteristics as diverse as adventitious rooting capacity, leaf morphology, canopy architecture, wood anatomy and reproductive development. Many concepts of phase change, the intensity and duration of changes that occur during the phase transition, and the practical consequences of plant maturation for growth and development, are poorly understood. Little is known about the physiological and environmental control of maturation in woody plants compared with herbaceous plants, and reliable markers of phase state have only been developed for a few species, mainly conifers. Understanding the mechanisms and forms of phase change is a prerequisite for achieving maturation or rejuvenation for applications such as seed production or clonal propagation. This review describes concepts, terminology and consequences of phase change, combining theoretical and practical aspects of tree maturation that relate to clonal forestry.

Influência do ácido indolbutírico e ds miniestaquia seriada no enraizamento e vigor de miniestacas de clones de Eucalyptus grandis

O presente estudo objetivou avaliar a eficiencia da miniestaquia seriada e o efeito da aplicacao do regulador de crescimento acido indolbutirico (AIB), nas concentracoes de 0, 500, 1.500 e 3.000 mg L-1, em relacao a sobrevivencia, ao enraizamento e vigor da parte aerea e do sistema radicular de miniestacas em quatro clones de Eucalyptus grandis. Com base nos resultados, a aplicacao do AIB nao resultou em aumento do enraizamento e sobrevivencia das miniestacas e no vigor geral das mudas, sendo em algumas caracteristicas e clones observados certos niveis de toxidez nas concentracoes acima de 500 mg L-1. Em relacao a miniestaquia seriada, esta proporcionou maior eficiencia na propagacao vegetativa dos clones de Eucalyptus grandis com menor grau de juvenilidade.

Características físicas e químicas de substratos para produção de mudas de Ilex paraguariensis St. Hil.

This work aimed to evaluate the physical and chemical properties of different materials and their compositions, as well as their efficiency in the production of Ilex paraguariensis seedlings in plastic tubes. The work was conducted at the Baldo S.A. Company nursery in Sao Mateus do Sul, PR, Brazil. Six materials were used to formulate 14 treatments: cattle manure, semi-decomposed sawdust, Ilex paraguariensis chopped stems, underground earth, commercial substrate based on pinus bark and earthworm humus. The results indicated that the treatments containing sawdust, Ilex paraguariensis stems and mainly cattle manure, besides being more economical, produced good quality seedlings. The treatments consisting of 40% cattle manure and 60% sawdust stood out because of the good cost-benefit ratio and the easiness of preparation. Substrate chemical characteristics did not affect the physical characteristics, as well the influence of physical characteristics on Ilex paraguariensis seedling production depends on the analyzed variable.

Estabelecimento, multiplicação e alongamento in vitro de Eucalyptus benthamii Maiden & Cambage x Eucalyptus dunnii Maiden

Neste trabalho foram testadas diferentes concentracoes de cloro ativo (NaOCl) na assepsia de explantes para o estabelecimento in vitro, bem como benzilaminopurina (BAP) e acido naftalenoacetico (ANA) para a multiplicacao e alongamento de Eucalyptus benthamii x Eucalyptus dunnii. As minicepas fornecedoras de propagulos para introducao in vitro foram conduzidas em minijardim clonal sob sistema semi-hidroponico. Segmentos nodais dos clones H12, H19 e H20 foram desinfestados com 0,5; 1,0; 1,5; e 2,0% (v/v) de cloro ativo durante 10 min e inoculados em meio de cultura MS. Na obtencao de brotacoes multiplas, utilizou-se o meio de cultura ½MS suplementado com 0; 0,25; 0,50; 0,75; e 1,0 mg L-1 de BAP. Na fase de alongamento, utilizou-se o meio de cultura ½MS com 0; 0,25; 0,50; 0,75; e 1,0 mg L-1 de ANA. Nao houve interacao entre os fatores estudados, obtendo-se 45%, 46% e 66% de estabelecimento do clone H12, H19 e H20, respectivamente. A concentracao de BAP que resultou na maior proliferacao de gemas axilares para o clone H12 aos 60 dias foi estimada na faixa de 0,25 e 0,30 mg L-1. Aos 60 dias, a faixa entre 0,25 e 0,75 mg L-1 de ANA promoveu o maior numero de brotacoes alongadas do clone H12.

Miniestaquia de Eucalyptus benthamii × Eucalyptus dunnii : (II) sobrevivência e enraizamento de miniestacas em função das coletas e estações do ano

This study aimed to evaluate, throughout the seasons, the minicutting technique as a cloning method for Eucalyptus benthamii x Eucalyptus dunnii hybrids regarding minicutting survival and rooting. The ministumps of H12, H19 and H20 clones were cultivated during 352 days in a clonal minigarden in a semi-hydroponic system in a sand bed, where the nutritive solution was supplied by drip irrigation. During the experiment, 27 successive minicutting samplings were performed in 4 seasons of the year: spring, summer, autumn and winter. The minicutting basal portion was immersed in hydro-alcoholic solutions containing 2,000 mg L -1 of IBA during 10 seconds. The experiment was conducted using an entirely randomized design with 5 replications and 20 minicuttings per replication. The minicutting rooting varied in function of the clone and presented high sensitivity to seasonal and temperature variations. The best rooting indices occurred in the cooler seasons (19.59% to 56.20%) and the lowest in warmer seasons (4.62% to 8.50%). The H19 and H20 clones presented the greater indices for rooting in all 4 seasons.

Influência da miniestaquia seriada no vigor radicular de clones de Eucalyptus grandis

The objective of the present study was to evaluate the influence of the serial minicutting technique on the rooting vigor of seedlings of four Eucalyptus grandis clones. Following seven minicutting subcultures, the minicuttings were rooted under greenhouse conditions (25 days), with acclimatization for 10 days in the shade and final seedling evaluation at 50 days old, under full light. In general, the serial subcultures promoted an increase in the number of roots and provided greater initial root vigor for clones with less rooting potential, suggesting a positive effect of the serial minicutting technique on Eucalyptus clones for these characteristics.

Miniestaquia seriada no rejuvenescimento de clones de Eucalyptus

O objetivo deste trabalho foi avaliar a eficiencia da tecnica de miniestaquia seriada em quatro clones de Eucalyptus grandis, quanto a sobrevivencia, ao enraizamento e ao crescimento em altura e diâmetro de colo das mudas. Foram realizados sete subcultivos pela miniestaquia seriada, por enraizamento sucessivo de brotacoes de minicepas, em casa de vegetacao durante 25 dias, seguido de aclimatacao por dez dias em casa de sombra e avaliacao final das mudas aos 50 dias de idade, em pleno sol. A miniestaquia seriada mostrou efeito positivo, principalmente em relacao aos clones que apresentaram menor potencial de enraizamento.

Produtividade e sobrevivência de minicepas de Eucalyptus benthamii Maiden et Cambage em sistema de hidroponia e em tubete.

This work aimed to evaluate the productivity and survival of Eucalyptus benthamii ministumps from seminal origin, handled in hydroponics systems and in plastic tubes. The survival differences was not verified among the handling systems studied, while for the productivity of the ministumps the hydroponic systems presented best results, with average of 8,1 minicuttings per ministumps per collection in comparison with 4,1 for the plastic tubes system. These results allowed to conclude that the handling of the ministumps in tubes and in hydroponic systems is technically viable, being the latter a more promising alternative for production of vegetative propagules of the species.

Efeito da dose de nitrogênio e de formulações de substratos na miniestaquia de Eucalyptus dunnii maiden

The aim of this study was to determine the influence of different nitrogen doses and substrate formulations on the minicutting technique of Eucalyptus dunnii Maiden. The clonal minigarden of 90-day- old seedlings was cultivated in the commercial substrate of pine bark and vermiculite (tubes of 55 cm3). The dose test used a unique source (NH4NO3) in the following concentrations of N: 0.2; 0.4 and 0.6 g L- 1. Each ministump was weekly watered with 10 mL of the tested solution. Five different substrate mixtures were tested: a commercial substrate with pine bark special, medium size vermiculite, carbonized rind of rice and incorporated fertilization. The survival of ministumps in the nitrogen doses tested was 100% until the 10th collection, after which, it was observed mortality in 0.4 treatment (1 ministump). All the evaluated characteristics showed direct relation to the N doses tested. The higher values were achieved with higher doses. The substrates presented statistical differences in the survival and formation of seedlings (collar diameter and height) and vegetative vigor of seedlings. In conclusion, the minicutting technique of E. dunnii is influenced by the nitrogen fertirrigation and the substrate. It is suggested the dose of 0.6 g L-1 and the substrate formed by the commercial substrate with pine bark and vermiculite + medium size vermiculite + carbonized rind of rice (1:1:1) + incorporated fertilization.