Modeling of morphological variables in Eucalyptus dunnii seedlings.

The morphological variables of forest seedlings may be indicative of its quality, having great importance to the success of forest enterprises. In this context, the aim of this study was to correlate the operationally measurable variables (stem diameter and height) with a destructive measurement (leaf area and root length) of E. dunnii seedlings in order to formulate equations that provide accurate estimates of these variables. For this, 77 seedlings were evaluated at 100 days old. The equations were formulated using the methodology "stepwise" for selecting the best combination of mathematical transformations of 45 operationally measurable variables. These equations were evaluated by statistical adjustment and precision, and subsequent validation by means of adherence test, with a confidence level of 99%, using 50 independent seedlings. The results indicated high correlation between the variables. For leaf area, the obtained adjusted coefficient of determination was 0.91 and standard error of estimate 15.2%. To root length, the adjusted coefficient of determination was 0.76 and standard error estimate of 22.5%. The two cases presented no residual bias and had been validated. as result, it is possible to formulate equations to obtain estimates of leaf area and root length in E. dunnii. As variáveis morfológicas de mudas florestais podem ser indicativos de sua qualidade, sendo de grande importância para o sucesso de empreendimentos florestais. Nesse contexto, o objetivo do estudo foi correlacionar as variáveis operacionalmente mensuráveis (diâmetro do colo e altura) com as de mensuração destrutiva (área foliar e comprimento de raiz) de mudas de E. dunnii, de modo a formular equações que forneçam estimativas precisas dessas variáveis. Para isso, avaliou-se 77 mudas com 100 dias de idade. As equações foram formuladas através da metodologia “stepwise” para seleção da melhor combinação entre 45 transformações matemáticas das variáveis operacionalmente mensuráveis. As equações foram avaliadas por estatísticas de ajuste e precisão, além de posterior validação por meio de um teste de aderência, a um nível de confiança de 99%, utilizando 50 mudas independentes. Observou-se alta correlação entre as variáveis. Para área foliar, obteve-se coeficiente de determinação ajustado de 0,91 e erro padrão da estimativa de 15,2%. Para comprimento de raiz, coeficiente de determinação ajustado de 0,76 e erro padrão da estimativa de 22,5%. Os dois casos não apresentaram tendenciosidade residual e foram validadas. Diante do exposto, é possível formular equações para obter estimativas de área foliar e comprimento de raiz em E. dunnii. AbstractModeling of morphological variables in Eucalyptus dunnii seedlings. The morphological variables of forest seedlings may be indicative of its quality, having great importance to the success of forest enterprises. In this context, the aim of this study was to correlate the operationally measurable variables (stem diameter and height) with a destructive measurement (leaf area and root length) of E. dunnii seedlings in order to formulate equations that provide accurate estimates of these variables. For this, 77 seedlings were evaluated at 100 days old. The equations were formulated using the methodology "stepwise" for selecting the best combination of mathematical transformations of 45 operationally measurable variables. These equations were evaluated by statistical adjustment and precision, and subsequent validation by means of adherence test, with a confidence level of 99%, using 50 independent seedlings. The results indicated high correlation between the variables. For leaf area, the obtained adjusted coefficient of determination was 0.91 and standard error of estimate 15.2%. To root length, the adjusted coefficient of determination was 0.76 and standard error estimate of 22.5%. The two cases presented no residual bias and had been validated. as result, it is possible to formulate equations to obtain estimates of leaf area and root length in E. dunnii.Keywords: Seedlings quality; leaf area; root length; mathematical models

Plantio misto de Eucalyptus urograndis e Acacia mearnsii em sistema agroflorestal: I - Produção de biomassa

This study aimed to evaluate a mixed stand of Eucalyptus urograndis and Acacia mearnsii in an agroforestry system with corn (Zea mays L.) in Bagé, RS. The design entailed a randomized block with five treatments and three replicates (T1- 100E; T2- 100A; T3- 50E:50A; T4- 75E:25A e T5- 25E:75A), with 4.0 m x 1.5 m planting space. Three lines of corn were planted, between the eucalyptus and/or black-wattle lines. Ten months after the installation, the biomass from forest species were quantified and separated in fractions (leaf, branch and stem). Corn biomass was collected at the end of the cycle and separated in fractions (leaf, straw, grain, corn cob and stem). In mixed stands, the treatment T5 (25E:75A) showed the highest biomass accumulation, being 35.1% in the leaves, 25.8% in branches and 39.1% in stem. The black wattle showed higher growth than the initial eucalyptus, both alone and in the mixed stand. The yield of corn was between 1.01 to 1.26 Mg ha-1, which was not statistically different (p>0.05) between treatments.Objetivou-se com o presente estudo quantificar a biomassa de um plantio misto de Eucalyptus urograndis e Acacia mearnsii em sistema agroflorestal com milho (Zea mays L.) no município de Bagé, RS. O delineamento utilizado foi blocos ao acaso com cinco tratamentos e três repetições (T1- 100E; T2-100A; T3-50E:50A; T4-75E:25A e T5-25E:75A), com espaçamento de 4,0 m x 1,5 m. Foram plantadas três linhas de milho, entre as fileiras de eucalipto e/ou acácia-negra. Aos 10 meses de idade, foi quantificada a biomassa das espécies florestais, que foram separadas por frações (folha, galho e tronco). A biomassa do milho foi coletada no final do ciclo e também separada por frações (folha, palha, grão, sabugo e colmo). Em plantio misto o tratamento T5 (25E:75A) apresentou o maior acúmulo de biomassa, sendo 35,1% nas folhas, 25,8% nos galhos e 39,1% no tronco. A acácia-negra apresentou maior crescimento inicial do que o eucalipto, tanto em monocultivo como em plantio misto. A produtividade do milho ficou entre 1,01 a 1,26 Mg ha-1, não diferindo estatisticamente (p > 0,05) entre os tratamentos

Mixed stands of Eucalyptus urograndis and Acacia mearnsii in an agroforestry system: I - Biomass production

Objetivou-se com o presente estudo quantificar a biomassa de um plantio misto de Eucalyptus urograndis e Acacia mearnsii em sistema agroflorestal com milho ( Zea mays L.) no munic\uedpio de Bag\ue9, RS. O delineamento utilizado foi blocos ao acaso com cinco tratamentos e tr\ueas repeti\ue7\uf5es (T1- 100E; T2-100A; T3-50E:50A; T4-75E:25A e T5-25E:75A), com espa\ue7amento de 4,0 m x 1,5 m. Foram plantadas tr\ueas linhas de milho, entre as fileiras de eucalipto e/ou ac\ue1cia-negra. Aos 10 meses de idade, foi quantificada a biomassa das esp\ue9cies florestais, que foram separadas por fra\ue7\uf5es (folha, galho e tronco). A biomassa do milho foi coletada no final do ciclo e tamb\ue9m separada por fra\ue7\uf5es (folha, palha, gr\ue3o, sabugo e colmo). Em plantio misto o tratamento T5 (25E:75A) apresentou o maior ac\ufamulo de biomassa, sendo 35,1% nas folhas, 25,8% nos galhos e 39,1% no tronco. A ac\ue1cia-negra apresentou maior crescimento inicial do que o eucalipto, tanto em monocultivo como em plantio misto. A produtividade do milho ficou entre 1,01 a 1,26 Mg ha-1, n\ue3o diferindo estatisticamente (p < 0,05) entre os tratamentos.This study aimed to evaluate a mixed stand of Eucalyptus urograndis and Acacia mearnsii in an agroforestry system with corn ( Zea mays L.) in Bag\ue9, RS. The design entailed a randomized block with five treatments and three replicates (T1- 100E; T2- 100A; T3- 50E:50A; T4- 75E:25A e T5- 25E:75A), with 4.0 m x 1.5 m planting space. Three lines of corn were planted, between the eucalyptus and/or black-wattle lines. Ten months after the installation, the biomass from forest species were quantified and separated in fractions (leaf, branch and stem). Corn biomass was collected at the end of the cycle and separated in fractions (leaf, straw, grain, corn cob and stem). In mixed stands, the treatment T5 (25E:75A) showed the highest biomass accumulation, being 35.1% in the leaves, 25.8% in branches and 39.1% in stem. The black wattle showed higher growth than the initial eucalyptus, both alone and in the mixed stand. The yield of corn was between 1.01 to 1.26 Mg ha-1, which was not statistically different (p<0.05) between treatments

Photosynthetic light response curves in Eucalyptus benthamii and Eucalyptus dunnii clones

The photosynthetic light-response curve reflects the instantaneous response of the net photosynthetic rate to different gradients of photosynthetically active radiation. Genetic materials can respond differently to light and consequently alter productivity. Thus, this work aimed to compare clones of Eucalyptus benthamii and Eucalyptus dunnii by checking the CO2 assimilation rate due to the increase in photosynthetically active radiation. The evaluations were carried out in mini-stumps implanted in a clonal mini-garden system. The CO2 assimilation rate curves were determined with the aid of a portable photosynthesis meter. The curves of CO2 assimilation rate (A) in response to the increase in photosynthetically active radiation (PAR) were evaluated at values of 1500, 1000, 700, 450, 250, 120, 50 and 0 μmol m-2 s -1 for clones of E. benthamii and E. dunnii. The three Eucalyptus clones evaluated showed a similar behavior of the A/PAR curve, showing a high demand for photosynthetically active radiation. In general, the three clones were very similar in terms of CO2 assimilation rate due to the increase in photosynthetically active radiation

Desenvolvimento de mudas de Schizolobium amazonicum Huber ex Ducke em diferentes ambientes em viveiro

This study aimed to evaluate the development of seedlings Schizolobium amazonicum under the effect of different environments nursery, the following treatments: T1 - seedlings in the open area, T2 - seedlings in shade house (75%) and T3 - green house. The variables analyzed were: survival rate, height of shoots (h), stem diameter (dc) and leaf number (nf). Seedling growth in height was greater in the greenhouse (50.3 cm), similar in shade house (49.0 cm) and lower in the seedlings in the open area (46.2 cm). For the stem diameter, seedlings of greenhouse had higher growth (6.6 mm), similar in shade house (6.3 mm), and higher in the open area, with the lowest growth (5.2 mm). The number of leaves in the greenhouse showed the best results (3.9), followed by shade house (3.5), which were higher than the open treatment (0,3). We conclude that the parica seedlings can be produced in a greenhouse or shade house, but not in the open due to damage from the cold to the seedlings.O objetivo do estudo foi avaliar o desenvolvimento de mudas de Schizolobium amazonicum sob o efeito de diferentes ambientes de viveiro, nos seguintes tratamentos: T1- mudas a pleno sol, T2 - mudas em casa de sombra (75%) e T3 - Casa de vegetação. As variáveis analisadas foram: índice de sobrevivência, altura da parte aérea (h), diâmetro do colo (dc) e número de folhas (nf). O crescimento em altura foi maior na casa de vegetação (50,3 cm), semelhante na casa de sombra (49,0 cm) e inferior nas mudas a céu aberto (46,2 cm). Quanto ao diâmetro de colo, as mudas da casa de vegetação tiveram crescimento maior (6,6 mm), semelhante na casa de sombra (6,3 mm), e superiores a céu aberto, com o menor crescimento (5,2 mm). O número de folhas na casa de vegetação apresentou os melhores resultados (3,9), seguidos pela casa de sombra (3,5), os quais foram superiores ao tratamento a céu aberto (0,3). Conclui-se que as mudas de paricá podem ser produzidas em casa de vegetação ou em casa de sombra, porém não a céu aberto, devido aos danos do frio às mudas

MINI-CUTTINGS ROOTING OF Sequoia sempervirens AT DIFFERENT IBA CONCENTRATIONS AND CLONES

Sequoia is a species that provides large volumes of wood, is resistant to decomposition and has seedling production by mini-cutting as a viable alternative. The aim of this work was to evaluate the rooting of mini-cuttings of different clones of Sequoia sempervirens and subsequent use of different concentrations of IBA in clones with low adventitious rooting. Mini-cuttings of different clones were used, from clonal mini-garden. In the experiment with the growth regulator, different concentrations of IBA (from 0 mg L-1 to 3000 mg L-1) were used. The material was placed to be rooted in a mini-tunnels and evaluate at 90 days. All experiments were installed in a completely randomized design, with a subsequent evaluation of survival (%), mini-cuttings with calluses (%), mini-cuttings rooted (%) and number of roots (only in the experiment with different concentrations of IBA). In the first experiment, the survival of mini-cuttings was high (close to 95%) and rooting showed great variation among the clones (22.8 to 100%). In the second experiment, using clones that previously presented rooting less than 50%, submitted to IBA application, high survival (88.1 to 99.4%) was observed. The clones presented different responses among themselves, but with improve in the rooting using growth regulator

Enraizamento de estacas de Tibouchina moricandiana var. vinacea em função da forma de aplicação e concentrações de AIB

Tibouchina moricandiana Baill. var. vinacea Handro is a woody shrub, native to Brazil with ornamental potential. The objective of this study was to evaluate the feasibility of cutting the vegetative propagation of the species according to the application form and different concentrations of indole butyric acid (IBA). Softwood cuttings were treated with 0, 1,000 and 2,000 mg kg-1/mg L-1 of IBA in powder and solution form. After 56 days the treatments were evaluated for rooting, cuttings with callus, survival, mortality, leaf retention, new shoots, number of roots per cutting and root length. The rooting of stem cuttings of T. moricandiana was negatively influenced by the concentrations of IBA or by way of application. The species has a high strike rate (90.8%), demonstrating a species with potential for vegetative propagation through cuttings. The form of application and concentration of IBA influenced other variables. The use of 2,000 mg kg-1 IBA applied by talc demonstrated a decrease in the number of roots and provided the greatest number of and unrooted live cuttings. The length of the three longest roots per cutting was higher with the use of 1,000 mg L-1 or mg kg-1 of IBA. The use of IBA for the rooting of cuttings can be dispensed with, but can be used at a concentration of 1,000 mg-1 or mg kg-1 to increase the length and number of roots.Tibouchina moricandiana Baill. var. vinacea Handro é um arbusto lenhoso, nativo do Brasil com grande potencial ornamental. Objetivou-se neste trabalho avaliar a viabilidade da estaquia na propagação vegetativa da espécie em função da forma de aplicação e diferentes concentrações de ácido indol butírico (AIB). Estacas semilenhosas foram tratadas com 0, 1.000 e 2.000 mg kg-1/mg L-1 de AIB na forma de talco e solução aquosa. Após 56 dias da aplicação dos tratamentos as estacas foram avaliadas quanto às porcentagens de enraizamento, estacas com calos, sobrevivência, mortalidade, retenção foliar, brotações novas; número de raízes por estaca e comprimento das três maiores raízes. A porcentagem de enraizamento das estacas caulinares de T. moricandiana foi influenciada negativamente pelas concentrações de AIB nem pela forma de aplicação. A espécie possui alta taxa de enraizamento (90,8%), mostrando ser uma espécie com potencialidade para a propagação vegetativa via estaquia. A forma de aplicação e concentração do AIB apresentaram influência em outras variáveis, o uso de 2.000 mg kg-1 de AIB aplicado em talco ocasionou a diminuição do número de raízes e proporcionou o maior número de estacas vivas e não enraizadas. O comprimento das três maiores raízes por estaca foi maior com o uso de 1.000 mg L-1 ou mg kg-1 de AIB. O uso de AIB no enraizamento das estacas pode ser dispensável, porém pode ser utilizado na concentração de 1.000 mg L-1 ou mg kg-1, aumentando-se o comprimento e o número de raízes

Resgate vegetativo e propagação de cedro‑australiano por estaquia

The objective of this work was to evaluate vegetative rescue methods for the production of cuttings (clearcutting, full annealing, and half‑annealing) of red cedar (Toona ciliata var. australis) mature trees. The number of produced shoots was evaluated at 60, 120 and 180 days, as well as the correlation between stem mean diameter at breast height (DBH) and the number of sprouts. From the resulting sprouts of each method, cuttings were produced and subjected to cutting and removal of leaflets, and then received the application of indolbutyric acid (IBA) (0 and 6,000 mg L‑1). Evaluations were made for the influence of the following factors on plant survival and rooting: rescue method, collection time, number of leaflets of cuttings, and matrix tree, in the presence and absence of IBA. There was no correlation between the DBH of trees and the number of produced shoots. Clearcutting at 120 days provided the highest increase of shoots (15.31). Cuttings obtained from half‑annealing had higher survival (57.8%) and rooting (55.5%) rates. Cuttings with two pairs of preserved leaflets and treated with 6,000 mg L‑1 IBA showed higher rates of survival (65.5%) and rooting (56.7%). There was wide variation in survival and rooting capacity among matrix trees. The vegetative rescue and propagation by cuttings have potential for clonal multiplication of Australian red cedar mature trees.O objetivo deste trabalho foi avaliar métodos de resgate vegetativo para a produção de estacas (corte raso, anelamento total e semianelamento) de árvores adultas de cedro-australiano (Toona ciliata var. australis). Avaliou-se o número de brotos produzidos aos 60, 120 e 180 dias, bem como a correlação entre o diâmetro médio do tronco à altura do peito (DAP) e o número de brotos. Com as brotações resultantes de cada método, produziram-se estacas que foram submetidas à retirada e ao corte de folíolos, e então receberam a aplicação de ácido indolbutírico (AIB) (0 e 6.000 mg L‑1). Avaliou-se a influência dos fatores método de resgate, tempo de coleta, número de folíolos das estacas e planta matriz, em presença e ausência de AIB, na sobrevivência e no enraizamento das estacas. Não houve correlação entre o DAP das árvores e o número de brotações. O corte raso aos 120 dias proporcionou a maior produção de brotos (15,31). Estacas obtidas do semianelamento apresentaram maior sobrevivência (57,8%) e enraizamento (55,5%). Estacas com dois pares de folíolos inteiros e tratadas com 6.000 mg L‑1 de AIB apresentaram maior sobrevivência (65,5%) e enraizamento (56,7%). Houve grande variação na sobrevivência e no enraizamento entre plantas matrizes. O resgate vegetativo e a estaquia apresentam potencial para multiplicação clonal de árvores adultas de cedro‑australiano

Crescimento inicial de mudas de Eucalyptus dunnii Maiden com utilização de polímero natural e substratos de cultivo

This study aimed to test different concentrations of natural polymer combined with different substrates in order to maximize the production and quality of Eucalyptus dunnii Maiden as well as the influence of the physical and chemical properties of the substrates. Experiments were conducted in a greenhouse in a randomized design with a 4 x 4 factorial arrangement for different substrates (factor "A") and water-retaining polymer concentrations (factor "B"). The physical and chemical properties of the substrates were also analyzed in each treatment. The seedlings height (H), neck diameter (D), shoot dry matter (SDM), root dry matter (RDM), total dry matter (TDM), H/D ratio and Dickson quality index (DQI) were measured after 90 days of sowing. Both the physical and chemical properties of the substrates have improved by the addition of hydrogel, especially those regarding to porosity, water availability and water holding capacity. In general, the water-retaining polymer concentrations of 2 and 4 g L-1 provided a better seedling growth. Seedlings largest neck diameter was observed at a hydrogel concentration of 6 g L-1. The use of hydrogel has resulted in higher height and neck diameter values when carbonized rice hulls were used as substrate. Therefore, hydrogel concentrations of 2 and 4 g L-1 may increase the quality of Eucalyptus dunnii seedlings and reduce their nursery time.O objetivo deste estudo foi testar diferentes doses do polímero à base de amido de milho combinado com diferentes substratos, visando à maximização da produção e qualidade de mudas de Eucalyptus dunnii Maiden e a influência das características físicas e químicas dos substratos. O experimento foi conduzido em casa de vegetação, utilizando delineamento inteiramente casualizado em arranjo fatorial 4 x 4, em que os níveis do fator "A" referiram-se aos diferentes subtratos e os níveis do fator "B" às doses do hidroretentor. Para cada tratamento realizou-se análise física e química do substrato. Após 90 dias da semeadura avaliouse a altura, diâmetro do colo, MMSPA, MMSR, MMST e o cálculo da relação h/dc e do IQD. A adição do hidrogel melhorou as características físicas e químicas dos substratos, principalmente às relacionadas com porosidade, disponibilidade de água e capacidade de retenção de água. As dosagens de 2 e 4 g L-1 do hidroretentor proporcionaram melhor crescimento das mudas. O maior diâmetro de coleto foi observado com a dose de 6 g L-1 do hidrogel. Quando a casca de arroz carbonizada foi utilizada, o uso do hidrogel proporcionou elevação da altura e diâmetro de coleto. Assim, o hidrogel, em dosagens entre 2 e 4 g L-1 pode melhorar a qualidade das mudas de Eucalyptus dunnii diminuindo o tempo de permanência no viveiro

Water stress and salinity on germination of Mimisa scabrella Benth. seeds

O objetivo foi avaliar os efeitos do estresse hídrico e da salinidade na germinação de sementes e desenvolvimento de plântulas M. scabrella. Realizaramse dois experimentos com diferentes potenciais osmóticos das soluções de PEG 6000 e NaCl. Os resultados demonstraram que a bracatinga é uma espécie promissora para cultivo em solos com estresse hídrico, seja por baixa precipitação, seja por solo salino, pois a germinação e a formação de plântulas ocorreram de forma satisfatória em potenciais osmóticos que estes solos apresentam.The objective was to evaluate the effects of water stress and salinity on seed germination and seedling development of M. scabrella. Two experiments were carried out with different osmotic potentials of PEG 6000 and NaCl solutions. The results showed that bracatinga is a promising species for cultivation in soils with water stress, either by precipitation low, or by saline soil, because germination and seedling formation occurred satisfactorily in the osmotic potentials that these soils present