Aloisio Xavier

Parâmetros morfológicos na avaliação da qualidade de mudas de eucalyptus grandis

An experiment was carried out to study the morphological parameters used to evaluate the quality of Eucalyptus grandis seedlings produced in different tube sizes. A mixture of 80% organic compound (CO) and 20% charcoal powder fertilized with and without N, P and K was used as substrate. Four sizes of hard plastic tubes at the volumes of 50, 110, 200 and 280 cm 3 were used as packaging. Height and height/weight relationship of the aerial part dry matter should be considered, since although providing a satisfactory contribution to seedling quality pattern, the parameters did not present a destructive process. The use of height only to estimate the quality of Eucalyptus grandis seedlings in the 110 cm 3 volume tube when they were 90-day old should be used, since it presents a satisfactory relative contribution, besides being a nondestructive, easily determined and measured parameter.

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.

Propagação vegetativa de cedro-rosa por miniestaquia

This work had the objective to evaluate the minicutting technique as a method for vegetative propagation of cedro-rosa (Cedrela fissilis), in terms of the production and survival of the ministumps after successive harvesting, as well as rooting and growth (height and root collar diameter) of the minicuttings. The minicuttings were obtained from seedlings of Cedrela fissilis, successively collected and submitted to different dosages of the growth regulator IBA. The results showed the efficiency of this technique in the vegetative propagation of this species. Up to 79% survival was obtained at 120 days of age, but when IBA was not applied, survival was higher. Overall, minicutting of Cedrela fissilis from material of seminal origin is technically viable. Its is an alternative method for producing seedlings of this species throughout the year, mainly when seeds are unavailable.

Enraizamento de miniestacas de clones híbridos de Eucalyptus globulus

The objective of this study was to evaluate the effect of the growth regulator indol butiric acid (IBA) on the rooting of apical and intermediate mini-cuttings of Eucalyptus urophylla x E. globulus and Eucalyptus grandis x E. globulus clones. The mini-cutting rooting was carried out for 30 days in acclimatized greenhouse and after the cuttings were transferred to shade house, where they remained for 10 days. The experimental design was in random blocks with a triple factorial arrangement constituted by two types of mini-cuttings (apical and intermediate), three IBA concentrations (0, 2000 and 4000 mg L -1 ) and eleven clones, in three repetitions, composed of 12 mini-cuttings per repetition. The IBA did not affect the characteristics evaluated. The survival and rooting of apical mini-cuttings were significantly higher. There was significant difference among clones regarding the evaluated variables, except for survival after 30 days in greenhouse.

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.

Enraizamento de miniestaca caulinar e foliar na propagação vegetativa de cedro-rosa (Cedrela fissilis Vell.)

This work aimed to evaluate the rooting of five different types of minicuttings (stem, apical stem, intermediate stem, apical stem with removed leaves and leaf), in the vegetative propagation of cedro-rosa (Cedrela fissilis), by applying the minicutting technique, using seedlings material. The results showed that stem cutting was the most efficient technique for the vegetative propagation of this species, with up to 84% survival at 90 days of age. Thus, this technique can be used as an alternative in the production of minicuttings of this species, throughout the year.

Dinâmica do enraizamento de microestacas e miniestacas de clones de Eucalyptus grandis

The aim of this work was to evaluate the dynamics of microcutting and minicutting techniques during rooting process, by monitoring root emergence and development in microcuttings and minicuttings of four Eucalyptus grandis clones. Microcuttings were obtained from in vitro rejuvenated plant-derived sprouts, whereas minicuttings from rooted sprouts derived from plants propagated through conventional cutting technique. The results suggest the greater rooting ability of the microcuttings as compared to the minicuttings, evidenced by the number of roots/cuttings, total root/cutting length, largest root/cutting length, mean length of roots/cutting and dry weight of roots.

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.