The quality and quantity of light are important factors in controlling in vitro plant growth in photoautotrophic systems. The aim of this study was to evaluate the influence of light quality (fluorescent, white, red, blue, red/blue, and distant red) on microstumps of a Eucalyptus urophylla clone in an in vitro photoautotrophic system, as well as the intensity of fluorescent light (60, 85, 100, and 140 μmol m–2 s–1) in the growth and production of microcutting. The number of shoots and microcutting, the size of the largest shoot, the stomatal density, chlorophyll, and carotenoid content were analyzed. Light quality altered plant growth, and fluorescent light intensity did not affect the microstumps’ production during the evaluation period. In white light-emitting diode (LED) light, there was higher production of carotenoids, with a lower initial production of microcuttings. A smaller number of shoots were obtained in blue LED. In general, the different qualities and light intensities tested allowed for the growth of the Eucalyptus urophylla clone grown in vitro, making it possible to obtain microcuttings under photoautotrophic cultivation. Study Implications In vitro propagation is a stressful process for plants and has limitations for commercial-scale Eucalyptus production. Fluorescent lamps, closed containers, and high sucrose concentrations are traditionally used. To reduce costs and improve production, the use of efficient light sources and photoautotrophic cultivation systems become alternatives. This study investigated the influence of light on the in vitro growth of a Eucalyptus clone in a photoautotrophic system. The quality was more important than the intensity of light. Foresters will be able to indicate the use of LEDs (light-emitting diodes) as a replacement for fluorescent lamps. This approach is useful in enhancing micropropagation techniques.

The objective of the present study was to test the effects of explant type, auxin concentrations, culture media, and auxin concentrations on the induction and proliferation of somatic embryos of Eucalyptus grandis x E. urophylla. Seeds and cotyledons were used as explants and inoculated in culture media containing 1.13, 2.26, 3.39 and 4.52 µM dicamba or 4.14, 10.35, 20.71 and 31.06 µM picloram. Embryogenic calli induced in the picloram treatments were used as explants and inoculated in semisolid or liquid media containing 4.14, 10.35, 20.71 and 31.06 µM picloram and keeping the origin of the embryogenic callus (seeds or cotyledons) and the concentration of picloram in those who were in the induction phase. Statistical, descriptive and anatomical analyses were performed. Induction of somatic pro-embryos into the juvenile plant material of Eucalyptus grandis x E. urophylla was performed using seeds or cotyledons as the source of explants, with the addition of dicamba and picloram as growth regulators. The use of cotyledons as a source of explants and the concentration of 4.1 µM picloram added to the culture media resulted in a higher induction of somatic pro-embryos. Proliferation of secondary somatic embryos was achieved using liquid medium added with picloram.

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Morphometric studies of fruits and forest seeds may indicate the presence of variability among individuals of the same species. The objective of this study was to investigate the morphometric diversity of fruits and seeds of Swietenia macrophylla in 20 individuals belong to the Parakanã Indigenous Land, PA, Brazil. The following characteristics of the fruits, wingless seeds, and seeds without testa of the 20 trees were evaluated. Analysis of variance was performed on the collected data, followed by test of the means by Scott-Knott test. Genetic dissimilarity was assessed through means of the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) grouping technique and canonical variables (CV). The results indicate high phenotypic diversity among mahogany fruits and seeds and the grouping of trees regardless is of the location of the indigenous village. Thus, mahogany trees have high genetic potential for germplasm conservation, seed harvesting, and breeding programs.

-The objective of this work was to evaluate the production and survival of the mini-stumps in mini-clonal hedge and the effect of leaf reduction of mini-cuttings on rooting and seedling growth of progenies of Vinhático (Plathymenia foliolosa) by mini-cutting. Apical mini-cuttings were used to evaluate the influence of leaf reduction on the rooting of vinhático; the mini-cuttings ranged between 8 to 10 cm in length and samples were subjected to100% leaf reduction (without leaf), 75% of leaf reduction, or no leaf reduction. As for the survival of mini-stumps in mini-clonal hedge, after the fourth successive mini-cuttings collection, P3 and P19 progenies showed the highest survival percentages (64.5% and 61.5%, respectively), while progenies P1 (32.3 %) and P45 (25%) showed the lowest values for this parameter. The average number of minicuttings/mini-stump/collection produced ranged from 0.83 (progeny 53) to 4.8 (progeny 01) and the average productivity was 120 m² mini-stumps/mini-cuttings per collection. These results suggest that leaf reduction in adventitious rooting in mini-cuttings did not result in any difference between foliar treatments without reduction and 75% leaf reduction; however, 100% mortality was observed when the mini-cuttings were made with total leaf reduction.The progenies studied showed potential regeneration of mini-stumps, thus allowing the realization of successive collections of young shoots.Keywords: Clonal forestry; Vegetative propagation; Cloning. PRODUÇÃO DE MINIESTACAS E O EFEITO DA REDUÇÃO FOLIAR NO ENRAIZAMENTO DE VINHÁTICO (Plathymenia foliolosa Benth.)RESUMO -Objetivou-se com o presente estudo avaliar a produção e sobrevivência de minicepas em minijardim clonal e o efeito da redução foliar das miniestacas no enraizamento e crescimento das mudas de progênies de vinhático (Plathymenia foliolosa) via miniestaquia. Foram utilizadas miniestacas da parte apical com altura variando de 8 a 10 cm de comprimento, sendo os tratamentos constituídos por 100% de redução foliar (sem folha), com 75% de redução foliar e sem redução foliar. Quanto à sobrevivência das minicepas em minijardim clonal, após a quarta coleta sucessiva de miniestacas, as progênies P3 e P19 apresentaram os maiores percentuais de sobrevivência (64,5% e 61,5%, respectivamente), enquanto as progênies P1 (32,3%) e P45 (25%), os menores valores observados quanto a essa avaliação. O número médio de miniestacas/ minicepa/coleta produzidas variou de 0,8 (progênie 53) a 4,8 (progênie 01), sendo a produtividade média das minicepas/m² de 120 miniestacas por coleta. Com base nos resultados obtidos, concluiu-se que há influência da redução foliar das miniestacas no enraizamento adventício, que os tratamentos sem redução foliar e com 75% de redução não apresentaram diferenças significativas, no entanto, foi observado 100% de mortalidade das miniestacas quando feita a redução total das folhas. Concluiu-se também que as progênies estudadas apresentaram potencial quanto à regeneração das minicepas, permitindo, assim, a realização ...