Silicon attenuates nutritional disorder of phosphorus in seedlings of Eucalyptus grandis × Eucalyptus urophylla.

BACKGROUND: Nutritional disorders of phosphorus (P), due to deficiency or toxicity, reduce the development of Eucalyptus spp. seedlings. Phosphorus deficiency often results in stunted growth and reduced vigor, while phosphorus toxicity can lead to nutrient imbalances and decreased physiological function. These sensitivities highlight the need for precise management of P levels in cultivation practices. The use of the beneficial element silicon (Si) has shown promising results under nutritional stress; nevertheless, comprehensive studies on its effects on Eucalyptus spp. seedlings are still emerging. To further elucidate the role of Si under varying P conditions, an experiment was conducted with clonal seedlings of a hybrid Eucalyptus spp. (Eucalyptus grandis × Eucalyptus urophylla, A207) in a soilless cultivation system. Seedlings were propagated using the minicutting method in vermiculite-filled tubes, followed by treatment with a nutrient solution at three P concentrations: a deficient dose (0.1 mM), an adequate dose (1.0 mM) and an excessive dose (10 mM), with and without the addition of Si (2mM). This study assessed P and Si concentration, nutritional efficiency, oxidative metabolism, photosynthetic parameters, and dry matter production. RESULTS: Si supply increased phenolic compounds production and reduced electrolyte leakage in seedlings provided with 0.1 mM of P. On the other hand, Si favored quantum efficiency of photosystem II as well as chlorophyll a content in seedlings supplemented with 10 mM of P. In general, Si attenuates P nutritional disorder by reducing the oxidative stress, favoring the non-enzymatic antioxidant system and photosynthetic parameters in seedlings of Eucalyptus grandis × Eucalyptus urophylla. CONCLUSION: The results of this study indicate that Eucalyptus grandis × Eucalyptus urophylla seedlings are sensitive to P deficiency and toxicity and Si has shown a beneficial effect, attenuating P nutritional disorder by reducing the oxidative stress, favoring the non-enzymatic antioxidant system and photosynthetic parameters.

Conociendo las propiedades del Eucalipto, ¿un alivio para la tos? / Knowing the properties of Eucalyptus, ¿a cough relief?

El eucalipto se ha empleado popularmente para tratar afecciones respiratorias. Muchas veces en nuestras consultas como médicos de familia, los pacientes con problemas respiratorios nos preguntan sobre esta práctica y sus efectos en la salud. Por esto, decidimos hacer una búsqueda de la evidencia disponible. Luego de realizar una búsqueda bibliográfica y seleccionar la evidencia más reciente y de mejor calidad, podemos decir, que el eucalipto tuvo un efecto estadísticamente significativo en comparación con el placebo en cuanto a los síntomas relacionados con la tos como así también en su frecuencia. Igualmente, concluimos que estos efectos del eucalipto sobre la tos en procesos respiratorios agudos, deberían tomarse con precaución, siempre informando a nuestros pacientes sobre la evidencia actual limitada disponible, sin olvidar las creencias de cada persona para la toma de decisiones (AU)

Eucalyptus has been popularly used to treat respiratory conditions. Many times in our consultations as family doctors, patients with respiratory problems ask us about this practice and its effects on health. For this reason, we decided to do a search of the available evidence. After conducting a literature search and selecting the most recent and best-quality evidence, we can say that eucalyptus had a statistically significant effect compared to placebo in terms of cough-related symptoms as well as their frequency . Likewise, we conclude that these effects of eucalyptus on coughing in acute respiratory processes should be taken with caution, always informing our patients about the limited current evidence available, without forgetting each person's beliefs for decision-making (AU)

Effect of Fertiactyl® on the absorption and translocation of 14C-glyphosate in young eucalyptus plants.

Fertiactyl® is a foliar fertilizer with the potential to minimize the phytotoxicity effects caused by glyphosate drift in eucalyptus plants. As the interactions of the glyphosate and Fertiactyl® in tank mix on the plant behavior are not yet known, the objective was to evaluate the absorption and translocation of 14C-glyphosate, applied isolated and mixed in tank with Fertiactyl®, in young eucalyptus plants (clone I-144, Eucalyptus urophylla x E. grandis). The addition of Fertiactyl® to the mixture of 14C-glyphosate reduced the absorption by 94.3% in relation to the total absorbed at the end of the evaluation compared to plants treated only with 14C-glyphosate, i.e., Fertiactyl® protected the eucalyptus plants of the glyphosate intoxication by drift. The translocation rates from the treated leaves to the rest of the shoots and roots were low (<2% of the total recovered) in both treatments, suggest that restricted translocation is a mechanism of natural tolerance to glyphosate in plants of clone I-144. It is concluded that Fertiactyl®, mixed in the solution with glyphosate, protects young eucalyptus plants against glyphosate drift by reducing the amount of herbicide absorbed.

Liming and macronutrient on early growth of Eucalyptus benthamii / Calcário e macronutrientes no crescimento inicial de Eucalyptus benthamii

Macronutrient suppression is one way to identify which chemical elements is the most important in the early development of seedlings of forest species. This study evaluated the initial growth of Eucalyptus benthamii seedlings through morphological and physiological variables, submitted to doses of N, P and K, and liming. The experimental design to install the experiment was completely randomized, with a 2x9 factorial scheme, in which levels of factor “A” referred to absence and presence of liming and levels of factor “B”, to the different treatments of NPK. Morphological variables of SD (stem diameter) and H (height) and the physiological variables of A (photosynthesis), E (transpiration), gs (stomatal conductance), Ci/Ca (relationship between intercellular and atmospheric CO2 concentration) and WUE (water use efficiency) were measured. For morphological variables, the absence of N directly affected the means and there was a direct relationship between increase of the dose and increase of SD and H. There was a positive relationship of P mainly in relation to shoot dry matter content (SDMC) and root dry matter content (RDMC). For the physiological variables, there was no direct response with the doses of N or P, with K being the element that most influenced the variables, especially when limestone was applied, resulting in higher averages for photosynthesis, transpiration and stomatal conductance. With the purpose of meeting the morphological and physiological demands, the recommendation for cultivation of Eucalyptus benthamii under the conditions of this study is the doses 150-200-150, without liming application.(AU)

A supressão dos macronutrientes é uma das maneiras de identificar qual ou quais dos elementos químicos é o mais importante no desenvolvimento inicial das mudas de espécies florestais. O estudo objetivou avaliar o crescimento inicial de mudas de Eucalyptus benthamii por meio de variáveis morfológicas e fisiológicas, submetidas a doses de N, P e K, e calagem. O delineamento experimental para instalação do experimento foi em delineamento inteiramente casualizado, com esquema fatorial 2x9, em que os níveis do fator “A” se referiram a ausência e a presença de calagem e os níveis do fator “B” aos diferentes tratamentos de NPK. Variáveis morfológicas de DAC (diâmetro a altura do colo) e H (altura) e as variáveis fisiológicas de A (fotossíntese), E (transpiração), gs (condutância estomática), Ci/Ca (relação entre a concentração intercelular e atmosférica de CO2) e WUE (eficiência no uso da água) foram determinadas. Para as variáveis morfológicas, a ausência do N afetou diretamente as médias, havendo uma relação direta entre o aumento da dose com o aumento das variáveis. Há uma relação positiva do P principalmente em relação a MSPA e MSPR. Para as variáveis fisiológicas, não houve resposta direta com as doses de N ou P, sendo o K o elemento que mais influenciou as variáveis, principalmente quando o calcário foi aplicado, resultando em maiores médias para fotossíntese, transpiração e condutância estomática. Com o objetivo de atender às demandas morfológicas e fisiológicas, a recomendação para o cultivo de Eucalyptus benthamii nas condições deste estudo é a dose 150-200-150, sem aplicação de calagem.(AU)

Essential oils in pathogen resistance induction of Eucalyptus benthamii Maiden et Cambage / Óleos essenciais na indução de resistência a patógenos em Eucalyptus benthamii Maiden et Cambage

This study evaluated the essential oils of Melaleuca alternifolia, Casearia sylvestris and Eugenia uniflora as inducers of defense mechanisms in Eucalyptus benthamii seedlings. Four mL of each oil, with a concentration of 0.75% were sprayed in E. benthamii seedlings and two bioassays were performed, in the first, the essential oils were sprayed and after 30 days, sugars, proteins, peroxidases, phenylalanine ammonia (PAL), and phenols were evaluated and; in the second, seven days after the first analysis, the essential oils were again sprayed and after three days, the same variables were evaluated. The essential oils of M. alternifolia, C. sylvestris, and E. uniflora sprayed had no significant effects on E. benthamii seedlings after 30 days in terms of total sugars, proteins, peroxidase, PAL activity, and phenols. However, when M. alternifolia and E. uniflora essential oils were sprayed seven days after the first analysis with evaluation after 3 days, an increase in total sugars was observed. After these days, all essential oils promoted an increase in protein levels. The oils of E. uniflora and C. sylvestris also increased peroxidase levels. The PAL defense enzyme not showed increased when essential oils were used. The essential oils of M. alternifolia and C. sylvestris had potential as inducers of defense mechanisms on E. benthamii seedlings after 3 days of their application, what it demonstrated not be permanent.(AU)

Este trabalho teve como objetivo avaliar os óleos essenciais de Melaleuca alternifolia, Casearia sylvestris e Eugenia uniflora como indutores de mecanismos de defesa em mudas de Eucalyptus benthamii. Quatro mL de cada óleo, com concentração de 0,75%, foram pulverizados em mudas de E. benthamii e foram realizados dois bioensaios. No primeiro foram pulverizados os óleos essenciais e após 30 dias, açúcares, proteínas, peroxidases, fenilalanina amônia (PAL) , e fenóis foram avaliados e; na segunda, sete dias após a primeira análise, os óleos essenciais foram novamente pulverizados e após três dias, as mesmas variáveis foram avaliadas. Os óleos essenciais de M. alternifolia, C. sylvestris e E. uniflora pulverizados não tiveram efeito significativo sobre as mudas de E. benthamii após 30 dias em termos de açúcares totais, proteínas, peroxidase, atividade PAL e fenóis. Entretanto, quando os óleos essenciais de M. alternifolia e E. uniflora foram pulverizados sete dias após a primeira análise com avaliação após três dias, foi observado um aumento nos açúcares totais. Depois desses dias, todos os óleos essenciais promoveram aumento nos níveis de proteínas. Os óleos de E. uniflora e C. sylvestris também aumentaram os níveis de peroxidase. A enzima de defesa PAL não se mostrou aumentada quando óleos essenciais foram usados. Os óleos essenciais de M. alternifolia e C. sylvestris apresentaram potencial como indutores de mecanismos de defesa em mudas de E. benthamii após três dias de sua aplicação, o que demonstrou não ser permanente.(AU)

Essential oils in pathogen resistance induction of Eucalyptus benthamii Maiden et Cambage / Óleos essenciais na indução de resistência a patógenos em Eucalyptus benthamii Maiden et Cambage

This study evaluated the essential oils of Melaleuca alternifolia, Casearia sylvestris and Eugenia uniflora as inducers of defense mechanisms in Eucalyptus benthamii seedlings. Four mL of each oil, with a concentration of 0.75% were sprayed in E. benthamii seedlings and two bioassays were performed, in the first, the essential oils were sprayed and after 30 days, sugars, proteins, peroxidases, phenylalanine ammonia (PAL), and phenols were evaluated and; in the second, seven days after the first analysis, the essential oils were again sprayed and after three days, the same variables were evaluated. The essential oils of M. alternifolia, C. sylvestris, and E. uniflora sprayed had no significant effects on E. benthamii seedlings after 30 days in terms of total sugars, proteins, peroxidase, PAL activity, and phenols. However, when M. alternifolia and E. uniflora essential oils were sprayed seven days after the first analysis with evaluation after 3 days, an increase in total sugars was observed. After these days, all essential oils promoted an increase in protein levels. The oils of E. uniflora and C. sylvestris also increased peroxidase levels. The PAL defense enzyme not showed increased when essential oils were used. The essential oils of M. alternifolia and C. sylvestris had potential as inducers of defense mechanisms on E. benthamii seedlings after 3 days of their application, what it demonstrated not be permanent.

Este trabalho teve como objetivo avaliar os óleos essenciais de Melaleuca alternifolia, Casearia sylvestris e Eugenia uniflora como indutores de mecanismos de defesa em mudas de Eucalyptus benthamii. Quatro mL de cada óleo, com concentração de 0,75%, foram pulverizados em mudas de E. benthamii e foram realizados dois bioensaios. No primeiro foram pulverizados os óleos essenciais e após 30 dias, açúcares, proteínas, peroxidases, fenilalanina amônia (PAL) , e fenóis foram avaliados e; na segunda, sete dias após a primeira análise, os óleos essenciais foram novamente pulverizados e após três dias, as mesmas variáveis foram avaliadas. Os óleos essenciais de M. alternifolia, C. sylvestris e E. uniflora pulverizados não tiveram efeito significativo sobre as mudas de E. benthamii após 30 dias em termos de açúcares totais, proteínas, peroxidase, atividade PAL e fenóis. Entretanto, quando os óleos essenciais de M. alternifolia e E. uniflora foram pulverizados sete dias após a primeira análise com avaliação após três dias, foi observado um aumento nos açúcares totais. Depois desses dias, todos os óleos essenciais promoveram aumento nos níveis de proteínas. Os óleos de E. uniflora e C. sylvestris também aumentaram os níveis de peroxidase. A enzima de defesa PAL não se mostrou aumentada quando óleos essenciais foram usados. Os óleos essenciais de M. alternifolia e C. sylvestris apresentaram potencial como indutores de mecanismos de defesa em mudas de E. benthamii após três dias de sua aplicação, o que demonstrou não ser permanente.

Liming and macronutrient on early growth of Eucalyptus benthamii / Calcário e macronutrientes no crescimento inicial de Eucalyptus benthamii

Macronutrient suppression is one way to identify which chemical elements is the most important in the early development of seedlings of forest species. This study evaluated the initial growth of Eucalyptus benthamii seedlings through morphological and physiological variables, submitted to doses of N, P and K, and liming. The experimental design to install the experiment was completely randomized, with a 2x9 factorial scheme, in which levels of factor “A” referred to absence and presence of liming and levels of factor “B”, to the different treatments of NPK. Morphological variables of SD (stem diameter) and H (height) and the physiological variables of A (photosynthesis), E (transpiration), gs (stomatal conductance), Ci/Ca (relationship between intercellular and atmospheric CO2 concentration) and WUE (water use efficiency) were measured. For morphological variables, the absence of N directly affected the means and there was a direct relationship between increase of the dose and increase of SD and H. There was a positive relationship of P mainly in relation to shoot dry matter content (SDMC) and root dry matter content (RDMC). For the physiological variables, there was no direct response with the doses of N or P, with K being the element that most influenced the variables, especially when limestone was applied, resulting in higher averages for photosynthesis, transpiration and stomatal conductance. With the purpose of meeting the morphological and physiological demands, the recommendation for cultivation of Eucalyptus benthamii under the conditions of this study is the doses 150-200-150, without liming application.

A supressão dos macronutrientes é uma das maneiras de identificar qual ou quais dos elementos químicos é o mais importante no desenvolvimento inicial das mudas de espécies florestais. O estudo objetivou avaliar o crescimento inicial de mudas de Eucalyptus benthamii por meio de variáveis morfológicas e fisiológicas, submetidas a doses de N, P e K, e calagem. O delineamento experimental para instalação do experimento foi em delineamento inteiramente casualizado, com esquema fatorial 2x9, em que os níveis do fator “A” se referiram a ausência e a presença de calagem e os níveis do fator “B” aos diferentes tratamentos de NPK. Variáveis morfológicas de DAC (diâmetro a altura do colo) e H (altura) e as variáveis fisiológicas de A (fotossíntese), E (transpiração), gs (condutância estomática), Ci/Ca (relação entre a concentração intercelular e atmosférica de CO2) e WUE (eficiência no uso da água) foram determinadas. Para as variáveis morfológicas, a ausência do N afetou diretamente as médias, havendo uma relação direta entre o aumento da dose com o aumento das variáveis. Há uma relação positiva do P principalmente em relação a MSPA e MSPR. Para as variáveis fisiológicas, não houve resposta direta com as doses de N ou P, sendo o K o elemento que mais influenciou as variáveis, principalmente quando o calcário foi aplicado, resultando em maiores médias para fotossíntese, transpiração e condutância estomática. Com o objetivo de atender às demandas morfológicas e fisiológicas, a recomendação para o cultivo de Eucalyptus benthamii nas condições deste estudo é a dose 150-200-150, sem aplicação de calagem.

The ideal percentage of K substitution by Na in Eucalyptus seedlings: Evidences from leaf carbon isotopic composition, leaf gas exchanges and plant growth.

Potassium (K) is the most required macronutrient by Eucalyptus, while sodium (Na) can partially substitute some physiological functions of K and have a positive response on plant growth in K-depleted tropical soils. However, the right percentage of K substitution by Na is not yet known for Eucalyptus seedlings, since a few experiments have only compared treatments receiving K or Na. This study evaluated five levels of Na supply (0, 0.45, 0.90, 1.35 and 1.80 mM) as substitution for K in Eucalyptus seedlings grown in nutrient solution. Plants growth, biomass, K-nutritional status, leaf gas exchange, leaf carbon isotopic composition (δ13C ‰), leaf water potential (Ψw), leaf area (LA), stomatal density (SD) and water use efficiency (WUE) were measured. The highest total biomass yield was achieved by the Na estimated rate of 0.25 mM, corresponding to a leaf K: Na ratio of 3.41, and having the lowest δ13C values. Conversely, the highest Na rate (1.8 mM) induced K deficiency symptoms, lower growth, reduced total dry matter yield, leaf gas exchange, LA, SD and a higher δ13C, which presented a trend to an inverse correlation with CO2 assimilation rate (A), WUE and shoot dry matter. Collectively, our results conclude that substitution of 25% of K by Na (0.45 mM of Na) provided significant gains in nutritional status and positive plant physiological responses by increasing WUE, stomatal diffusion, and by augmenting CO2 uptake efficiency. This nutritional management can therefore be an alternative option to optimize yields and resource use efficiencies in Eucalyptus cultivation.

Carfentrazone-ethyl and glyphosate drift inhibits uredinial formation of Austropuccinia psidii on Eucalyptus grandis leaves.

BACKGROUND: The response to infection of Austropuccinia psidii in resistant (CLR-383) and susceptible (CLR-384) Eucalyptus grandis clones, exposed to herbicide drift of carfentrazone-ethyl, glyphosate and a mixture of these two herbicides, was evaluated at microscopic and physiological levels. RESULTS: Plants of the two clones showed symptoms of phytotoxicity caused by herbicide drift. However, net CO2 assimilation rate, height and shoot dry matter were lower in CLR-384 than in CLR-383. At the ultrastructure level, the leaves of both clones exposed to the herbicides showed thylakoid disorganization and accumulation of starch grains in the chloroplasts. Only plants of CLR-384 were infected by A. psidii, but when exposed to herbicide drift, rust severity was lower than in control plants. Six days after inoculation (dai), plants of this clone exposed to the herbicides had smaller uredinia than control plants. At 12 dai, non-herbicide treated plants showed normal uredinia, containing abundant urediniospores. By contrast, plants exposed to the herbicides were less colonized by the fungus, and the uredinia were smaller with reduced production of urediniospores, which were sometimes not even detected. CONCLUSION: Glyphosate and carfentrazone-ethyl herbicide drift reduce infection and uredinial formation of A. psidii and to some extent induce basal resistance in a susceptible clone of E. grandis. © 2018 Society of Chemical Industry.

Effects of sewage sludge application on unfertile tropical soils evaluated by multiple approaches: A field experiment in a commercial Eucalyptus plantation.

Sewage sludge (SS) reuse in forest plantation as soil fertilizer/amendment has tremendously increased in recent years. However, SS may have high concentrations of potentially toxic elements (PTE), representing a potential risk for soil and the whole ecosystem. This paper was aimed to assess the toxicity of PTE in unfertile tropical soils amended with SS in a commercial Eucalyptus plantation, with an integrated multiple approaches combining: i) the use of a battery of bioassays (Daphnia magna, Pseudokcrichirella subcapitata, Lactuca sativa, and Allium cepa); and ii) the evaluation of some PTE (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) and their availability into the pedoenvironment. Differences in total and available PTE between SS doses and time of treatments were evaluated using ANOVA; correlations between PTE and bioassays by a sparse partial robust M-regression (SPRM), while multiple correlations among parameters were performed by principal factor analysis (PFA). Results show that PTE contents in soils tended to increase with SS application doses. However this cannot be assumed as a general rule since in all the investigated treatments the PTE concentrations were consistently below both soil natural background concentrations and quality reference values. Bioassays showed a generalized low eco- and genotoxicity of SS with an increase in toxicity at increasing SS doses but with a clear decreasing trend as time went by. A. cepa was the most sensitive bioassay followed by P. subcapitata > D. magna > L. sativa. Overall, the results indicate that in realistic open field conditions SS risk may be lower than expected due to dynamic decrease in PTE toxicity with time after application. This study has an important implication that open-field trials should be strongly encouraged for evaluating environmental risk of SS application in forestry.

Nutrient acquisition and eucalyptus growth affected by humic acid sources and concentrations / Aquisição de nutrientes e crescimento do eucalipto sob efeito de fontes e concentrações de ácido húmico

Humic acid (HA) can increase eucalyptus growth due to its biostimulant effect and improvement in plant nutrient uptake. Magnitude of these stimuli varies according to the source, chemical composition, presence of bioactive fragments, and concentration of HA. The aim of this study was to evaluate the effect of HA sources and concentrations on dry matter, accumulation and uptake efficiency (UpE) of nutrients for eucalyptus seedlings cultivated in nutrient solution. A randomized block experimental design was adopted, with four replications, in a 3x4+1 factorial scheme, in which three sources of HA (HA-L1 and HA-L2, derived from different commercial HA extracted from leonardite with 0.5 mol L-1 NaOH and 0.5 mol L-1 KOH, respectively, and HA-Com, which was extracted from compost with 0.5 mol L-1 KOH) were combined with four concentrations of C-HA (5, 10, 25, and 100 mg L-1) as well as a control treatment in which eucalyptus was cultivated without HA. Eucalyptus seedlings were grown for 20 days, maintaining three plants per pot. At the end of the experiment, production of shoot dry matter (SDM), root dry matter (RDM), and total dry matter (TDM); the Root: Shoot dry matter ratio; and the accumulations of N, P, K, Ca, B, Cu, Fe, and Zn in the shoot and root were evaluated as well as the UpE of these nutrients by the seedlings. Maximum production of SDM was reached at the concentrations of 14 and 13.5 mg L-1 of C-HA, for HA-L1 and HA-Com, respectively. The RDM increased with the use of HA-Com, with optimal concentration of 55 mg L-1 of C-HA. Accumulation of Fe in the eucalyptus shoot decreased in HA-treated pots, compromising Fe translocation from the root to the shoot. Regardless of HA source used, Cu accumulation by plants diminishes as C-HA concentration increases. A greater growth of eucalyptus at concentrations lower than 15 mg L-1 of C-HA occurs more through the stimulus to shoot and root growth than due to greater acquisition and UpE of nutrients by plants...(AU)

O ácido húmico (AH) pode aumentar o crescimento do eucalipto devido a seu efeito bioestimulante e aumento da absorção de nutrientes pelas plantas. A magnitude desses estímulos varia conforme a fonte, composição química, presença de fragmentos bioativos e concentração de AH. Objetivou-se, assim, avaliar o efeito de fontes e concentrações de AH na massa seca, aquisição e eficiência de absorção (EAbs) de nutrientes por mudas de eucalipto cultivadas em solução nutritiva. O experimento foi realizado em delineamento de blocos casualizados, com quatro repetições, em esquema fatorial 3x4+1, sendo testadas três fontes de AH (AH-L1 e AH-L2, derivados de diferentes produtos comerciais de AH, tendo como material de extração leonardita, sendo extraídos com NaOH 0,5 mol L-1 e KOH 0,5 mol L-1, respectivamente e o AH-Com, que foi extraído de composto, com KOH 0,5 mol L-1), que foram combinadas com quatro concentrações de C-AH (5, 10, 25 e 100 mg L-1), além de um tratamento controle onde o cultivo do eucalipto foi feito sem aplicação de AH. Mudas de eucalipto foram cultivadas durante 20 dias, mantendo-se três plantas por vaso. Ao final do experimento, foram avaliados a produção de massa seca da parte aérea (MSPA), raiz (MSR) e total (MST), relação de massa seca raiz/parte aérea e os acúmulos de N, P, K, Ca, B, Cu, Fe e Zn na parte aérea e raiz, além da EAbs desses nutrientes pelas mudas de eucalipto. Há máxima produção de MSPA para concentrações de 14 e 13,5 mg L-1 de C-AH, respectivamente, para AH-L1 e AH-Com. A MSR aumentou com o uso de AH de composto, sendo máximo o crescimento de raiz para a concentração de 55 mg L-1 de C-AH. O acúmulo de Fe na parte aérea do eucalipto diminuiu com a aplicação de AH, comprometendo a translocação do nutriente da raiz para a parte aérea. Há restrição severa no acúmulo de Cu pelas plantas à medida que se aumenta a concentração de C-AH, independentemente da fonte de AH utilizada...(AU)

Nutrient acquisition and eucalyptus growth affected by humic acid sources and concentrations / Aquisição de nutrientes e crescimento do eucalipto sob efeito de fontes e concentrações de ácido húmico

Humic acid (HA) can increase eucalyptus growth due to its biostimulant effect and improvement in plant nutrient uptake. Magnitude of these stimuli varies according to the source, chemical composition, presence of bioactive fragments, and concentration of HA. The aim of this study was to evaluate the effect of HA sources and concentrations on dry matter, accumulation and uptake efficiency (UpE) of nutrients for eucalyptus seedlings cultivated in nutrient solution. A randomized block experimental design was adopted, with four replications, in a 3x4+1 factorial scheme, in which three sources of HA (HA-L1 and HA-L2, derived from different commercial HA extracted from leonardite with 0.5 mol L-1 NaOH and 0.5 mol L-1 KOH, respectively, and HA-Com, which was extracted from compost with 0.5 mol L-1 KOH) were combined with four concentrations of C-HA (5, 10, 25, and 100 mg L-1) as well as a control treatment in which eucalyptus was cultivated without HA. Eucalyptus seedlings were grown for 20 days, maintaining three plants per pot. At the end of the experiment, production of shoot dry matter (SDM), root dry matter (RDM), and total dry matter (TDM); the Root: Shoot dry matter ratio; and the accumulations of N, P, K, Ca, B, Cu, Fe, and Zn in the shoot and root were evaluated as well as the UpE of these nutrients by the seedlings. Maximum production of SDM was reached at the concentrations of 14 and 13.5 mg L-1 of C-HA, for HA-L1 and HA-Com, respectively. The RDM increased with the use of HA-Com, with optimal concentration of 55 mg L-1 of C-HA. Accumulation of Fe in the eucalyptus shoot decreased in HA-treated pots, compromising Fe translocation from the root to the shoot. Regardless of HA source used, Cu accumulation by plants diminishes as C-HA concentration increases. A greater growth of eucalyptus at concentrations lower than 15 mg L-1 of C-HA occurs more through the stimulus to shoot and root growth than due to greater acquisition and UpE of nutrients by plants...

O ácido húmico (AH) pode aumentar o crescimento do eucalipto devido a seu efeito bioestimulante e aumento da absorção de nutrientes pelas plantas. A magnitude desses estímulos varia conforme a fonte, composição química, presença de fragmentos bioativos e concentração de AH. Objetivou-se, assim, avaliar o efeito de fontes e concentrações de AH na massa seca, aquisição e eficiência de absorção (EAbs) de nutrientes por mudas de eucalipto cultivadas em solução nutritiva. O experimento foi realizado em delineamento de blocos casualizados, com quatro repetições, em esquema fatorial 3x4+1, sendo testadas três fontes de AH (AH-L1 e AH-L2, derivados de diferentes produtos comerciais de AH, tendo como material de extração leonardita, sendo extraídos com NaOH 0,5 mol L-1 e KOH 0,5 mol L-1, respectivamente e o AH-Com, que foi extraído de composto, com KOH 0,5 mol L-1), que foram combinadas com quatro concentrações de C-AH (5, 10, 25 e 100 mg L-1), além de um tratamento controle onde o cultivo do eucalipto foi feito sem aplicação de AH. Mudas de eucalipto foram cultivadas durante 20 dias, mantendo-se três plantas por vaso. Ao final do experimento, foram avaliados a produção de massa seca da parte aérea (MSPA), raiz (MSR) e total (MST), relação de massa seca raiz/parte aérea e os acúmulos de N, P, K, Ca, B, Cu, Fe e Zn na parte aérea e raiz, além da EAbs desses nutrientes pelas mudas de eucalipto. Há máxima produção de MSPA para concentrações de 14 e 13,5 mg L-1 de C-AH, respectivamente, para AH-L1 e AH-Com. A MSR aumentou com o uso de AH de composto, sendo máximo o crescimento de raiz para a concentração de 55 mg L-1 de C-AH. O acúmulo de Fe na parte aérea do eucalipto diminuiu com a aplicação de AH, comprometendo a translocação do nutriente da raiz para a parte aérea. Há restrição severa no acúmulo de Cu pelas plantas à medida que se aumenta a concentração de C-AH, independentemente da fonte de AH utilizada...

Carbon assimilation in Eucalyptus urophylla grown under high atmospheric CO2 concentrations: A proteomics perspective.

Photosynthetic organisms may be drastically affected by the future climate projections of a considerable increase in CO2 concentrations. Growth under a high concentration of CO2 could stimulate carbon assimilation-especially in C3-type plants. We used a proteomics approach to test the hypothesis of an increase in the abundance of the enzymes involved in carbon assimilation in Eucalyptus urophylla plants grown under conditions of high atmospheric CO2. Our strategy allowed the profiling of all Calvin-Benson cycle enzymes and associated protein species. Among the 816 isolated proteins, those involved in carbon fixation were found to be the most abundant ones. An increase in the abundance of six key enzymes out of the eleven core enzymes involved in carbon fixation was detected in plants grown at a high CO2 concentration. Proteome changes were corroborated by the detection of a decrease in the stomatal aperture and in the vascular bundle area in Eucalyptus urophylla plantlets grown in an environment of high atmospheric CO2. Our proteomics approach indicates a positive metabolic response regarding carbon fixation in a CO2-enriched atmosphere. The slight but significant increase in the abundance of the Calvin enzymes suggests that stomatal closure did not prevent an increase in the carbon assimilation rates. BIOLOGICAL SIGNIFICANCE: The sample enrichment strategy and data analysis used here enabled the identification of all enzymes and most protein isoforms involved in the Calvin-Benson-Bessham cycle in Eucalyptus urophylla. Upon growth in CO2-enriched chambers, Eucalyptus urophylla plantlets responded by reducing the vascular bundle area and stomatal aperture size and by increasing the abundance of six of the eleven core enzymes involved in carbon fixation. Our proteome approach provides an estimate on how a commercially important C3-type plant would respond to an increase in CO2 concentrations. Additionally, confirmation at the protein level of the predicted genes involved in carbon assimilation may be used in plant transformation strategies aiming to increase plant adaptability to climate changes or to increase plant productivity.

Model-data synthesis for the next generation of forest free-air CO2 enrichment (FACE) experiments.

The first generation of forest free-air CO2 enrichment (FACE) experiments has successfully provided deeper understanding about how forests respond to an increasing CO2 concentration in the atmosphere. Located in aggrading stands in the temperate zone, they have provided a strong foundation for testing critical assumptions in terrestrial biosphere models that are being used to project future interactions between forest productivity and the atmosphere, despite the limited inference space of these experiments with regards to the range of global ecosystems. Now, a new generation of FACE experiments in mature forests in different biomes and over a wide range of climate space and biodiversity will significantly expand the inference space. These new experiments are: EucFACE in a mature Eucalyptus stand on highly weathered soil in subtropical Australia; AmazonFACE in a highly diverse, primary rainforest in Brazil; BIFoR-FACE in a 150-yr-old deciduous woodland stand in central England; and SwedFACE proposed in a hemiboreal, Pinus sylvestris stand in Sweden. We now have a unique opportunity to initiate a model-data interaction as an integral part of experimental design and to address a set of cross-site science questions on topics including responses of mature forests; interactions with temperature, water stress, and phosphorus limitation; and the influence of biodiversity.

Sources and application methods of boron in eucalyptus crop / Fontes e modos de aplicação de boro na cultura do eucalipto

Cerrado soils have low boron (B) content, making supplementation of this element through fertilization via soil and/or leaf is a common practice. It is therefore important to establish the best mode of application and source of B for the proper development of eucalyptus. Thus, the objective of this study was to compare the effect of B sources with high and low solubility on eucalyptus cultivation and to examine the effect of foliar application of the micronutrient. The experiment was conducted in an area located at 20o 34 S latitude and 51o 50 W longitude with an altitude of 305 m during the period from January 2012 to February 2014. The experiment was set up using a randomised complete block design with six treatments and five replications, in a 3 x 2 factorial scheme, consisting of 0 kg ha-1 of B, 1 kg ha-1 of B using boric acid as a source (high solubility, 17% B) or 1 kg ha-1 of B using borogran as a source (low solubility, 10% B), applied to the planting furrow, with or without foliar application of 0.5% boric acid in a solution with a volume of 250 L ha-1. Except for the case of foliar B application, there was an increase in plant height in treatments that received the micronutrient at planting, which differed significantly from the control. However, both sources, independent of solubility, exhibited similar results. The two foliar B applications were sufficient to caus...(AU)

Os solos de Cerrado apresentam baixo teor de boro (B) no solo, sendo comum a suplementação deste elemento através da adubação via solo e/ou foliar. Portanto, é importante definir qual o melhor modo de aplicação e fonte de B para o bom desenvolvimento do eucalipto. Assim, o objetivo deste trabalho foi comparar o efeito de fontes de B com alta e baixa solubilidade na cultura do eucalipto, bem como a aplicação foliar do micronutriente. O experimento foi conduzido em uma área com latitude 20o 34 S e longitude 51o 50 O e altitude de 305 m, no período de 01/2012 a 02/2014. O delineamento experimental foi o de blocos casualizados com seis tratamentos e cinco repetições, dispostos em um esquema fatorial de 3 x 2, sendo: 0 kg ha-1 de B, 1 kg ha-1 de B utilizando como fonte o ácido bórico (alta solubilidade, 17% B) ou1 kg ha-1 de B utilizando como fonte o borogran (baixa solubilidade, 10% B), aplicados no sulco de plantio, com ou sem aplicações de ácido bórico via foliar na dose de 0,5% de ácido bórico na calda com volume de 250 L ha-1. Com a omissão de B via foliar houve incremento em altura de plantas nos tratamentos que receberam a aplicação do micronutriente no plantio, diferindo significativamente da testemunha. Porém, ambas as fontes, independente da solubilidade, apresentaram resultados semelhantes. As duas aplicações de B via foliar foram suficientes para que houvesse...(AU)

Concerted transcription of auxin and carbohydrate homeostasis-related genes underlies improved adventitious rooting of microcuttings derived from far-red treated Eucalyptus globulus Labill mother plants.

Economically important plant species, such as Eucalyptus globulus, are often rooting recalcitrant. We have previously shown that far-red light enrichment applied to E. globulus donor-plants improved microcutting rooting competence and increased rooting zone/shoot carbohydrate ratio. To better understand this developmental response, the relative expression profiles of genes involved in auxin signaling (ARF6, ARF8, AGO1), biosynthesis (YUC3) and transport (AUX1, PIN1, PIN2); sucrose cleavage (SUS1, CWINV1), transport (SUC5), hexose phosphorylation (HXK1, FLN1) and starch biosynthesis (SS3) were quantified during adventitious rooting of E. globulus microcuttings derived from donor plants exposed to far-red or white light. Expression of auxin transport-related genes increased in the first days of root induction. Far-red enrichment of donor plants induced ARF6, ARF8 and AGO1 in microcuttings. The first two gene products could activate GH3 and other rooting related genes, whereas AGO1 deregulation of the repressor ARF17 may relief rooting inhibition. Increased sink strength at the basal stem with sucrose unloading in root tissue mediated by SUC and subsequent hydrolysis by SUS1 were also supported by gene expression profile. Fructose phosphorylation and starch biosynthesis could also contribute to proper carbon allocation at the site of rooting, as evidenced by increased expression of related genes. These data are in good agreement with increased contents of hexoses and starch at the cutting base severed from far-red exposed donor plants. To sum up, pathways integrating auxin and carbohydrate metabolism were activated in microcuttings derived from donor plants exposed to far red light enrichment, thereby improving rooting response in E. globulus.

Temporal dynamics of the response to Al stress in Eucalyptus grandis × Eucalyptus camaldulensis.

Lipid peroxidation and root elongation of Eucalyptus grandis × Eucalyptus camaldulensis were studied under stress conditions in response to aluminum (Al), a metal known to limit agricultural productivity in acidic soils primarily due to reduced root elongation. In Brazil, the Grancam 1277 hybrid (E. grandis × E. camaldulensis) has been planted in the "Cerrado", a region of the country with a wide occurrence of acidic soils. The present study demonstrated that the hybrid exhibited root growth reduction and increased levels of lipid peroxidation after 24h of treatment with 100 µM of Al, which was followed by a reduction in lipid peroxidation levels and the recovery of root elongation after 48 h of Al exposure, suggesting a rapid response to the early stressful conditions induced by Al. The understanding of the temporal dynamics of Al tolerance may be useful for selecting more tolerant genotypes and for identifying genes of interest for applications in bioengineering.

Doses of N, P and K in the cultivation of eucalyptus in soil originally under Cerrado vegetation / Doses de N, P e K na cultura do eucalipto em solo originalmente sob Cerrado

Many eucalyptus plantations in Brazil are in areas of soil with low fertility, with little phosphorous (P) and potassium (K) availability and with low organic matter (OM) content, resulting in a low supply of nutrients to plants, directly reflected in reduced yield. Thus, our objective was to evaluate the effects of nitrogen (N), P and K fertilization on the growth of eucalyptus plants, with the aim of achieving nutritional balance and high yield. The experiment was conducted on Renascença Farm, an agricultural property administered by Cargill Agrícola S.A., located in the city of Três Lagoas, Mato Grosso do Sul state, Brazil. The experimental design consisted of randomized blocks with ten treatments and five replicates. The treatments were composed of doses of N (0, 70, 105 and 140 kg ha-1), doses of P (0,40, 70 and 100 kg ha-1 of P2O5) and doses of K (0, 90, 135 and 180 kg ha-1 of K2O). The doses of N and K were applied at planting and as top dressing, and the doses of P were applied only at planting. The diameter at breast height (DBH), plant height and timber volume with bark were assessed, and the concentrations of macronutrients in the leaves were determined. DBH and volume were positively affected by N fertilization, and eucalyptus growth in DBH, height and volume increased with P and K fertilization. The maximum yield of eucalyptus at 21 months of age was obtained with the application of71 kg ha-1 of N, 100 kg ha-1 of P2O5 and 125 kg ha-1 of K2O. The concentrations of macronutrients wereadequate even in the absence of the application of N, P and K. With increasing doses of K, there was an increase in leaf concentrations of K and a decrease in those of calcium and magnesium.

Grande parte do plantio da cultura do eucalipto no Brasil encontra-se em área de solo de baixa fertilidade, com pouca disponibilidade de fósforo (P) e potássio (K), e baixo teor de matéria orgânica (M.O.), o que implica em baixo fornecimento de nutrientes à planta, refletindo diretamente na redução da produtividade. Neste sentido, objetivou-se avaliar a adubação nitrogenada, fosfatada e potássica no crescimento das plantas de eucalipto visando equilíbrio nutricional e alta produtividade. O experimento foi executado na Fazenda Renascença, fundo agrícola administrado pela Cargill Agrícola S/A, localizado no município de Três Lagoas/MS. O delineamento experimental foi o de blocos casualizados com dez tratamentos e cinco repetições. Os tratamentos foram constituídos por doses de nitrogênio (N) (0, 70, 105 e 140 kg ha-1), doses de P (0, 40, 70 e 100 kg ha-1 de P2O5) e doses de K (0, 90, 135 e 180 kg ha-1 de K2O). As doses de N e K foram aplicadas no plantio e em cobertura e as doses de P somente no plantio. Foram avaliados: o diâmetro à altura do peito (DAP), a altura de plantas, o volume de madeira com casca e determinados as concentrações de macronutrientes nas folhas. O DAP e o volume foram influenciados positivamente pela fertilização nitrogenada, já o crescimento do eucalipto em DAP, a altura e o volume aumentaram com a adubação fosfatada e potássica. A máxima produtividade do eucalipto aos 21 meses de idade foi obtida com aplicação de 71 kg ha-1 de N, 100 kg ha-1 de P2O5 e 125 kg ha-1 de K2O. As concentrações dos macronutrientes estiveram adequadas mesmo na ausência da aplicação de N, P e K. Com o aumento das doses de K houve incremento das concentrações foliares de K e diminuição das de cálcio e magnésio.

Sources and application methods of boron in eucalyptus crop / Fontes e modos de aplicação de boro na cultura do eucalipto

Cerrado soils have low boron (B) content, making supplementation of this element through fertilization via soil and/or leaf is a common practice. It is therefore important to establish the best mode of application and source of B for the proper development of eucalyptus. Thus, the objective of this study was to compare the effect of B sources with high and low solubility on eucalyptus cultivation and to examine the effect of foliar application of the micronutrient. The experiment was conducted in an area located at 20o 34 S latitude and 51o 50 W longitude with an altitude of 305 m during the period from January 2012 to February 2014. The experiment was set up using a randomised complete block design with six treatments and five replications, in a 3 x 2 factorial scheme, consisting of 0 kg ha-1 of B, 1 kg ha-1 of B using boric acid as a source (high solubility, 17% B) or 1 kg ha-1 of B using borogran as a source (low solubility, 10% B), applied to the planting furrow, with or without foliar application of 0.5% boric acid in a solution with a volume of 250 L ha-1. Except for the case of foliar B application, there was an increase in plant height in treatments that received the micronutrient at planting, which differed significantly from the control. However, both sources, independent of solubility, exhibited similar results. The two foliar B applications were sufficient to caus...

Os solos de Cerrado apresentam baixo teor de boro (B) no solo, sendo comum a suplementação deste elemento através da adubação via solo e/ou foliar. Portanto, é importante definir qual o melhor modo de aplicação e fonte de B para o bom desenvolvimento do eucalipto. Assim, o objetivo deste trabalho foi comparar o efeito de fontes de B com alta e baixa solubilidade na cultura do eucalipto, bem como a aplicação foliar do micronutriente. O experimento foi conduzido em uma área com latitude 20o 34 S e longitude 51o 50 O e altitude de 305 m, no período de 01/2012 a 02/2014. O delineamento experimental foi o de blocos casualizados com seis tratamentos e cinco repetições, dispostos em um esquema fatorial de 3 x 2, sendo: 0 kg ha-1 de B, 1 kg ha-1 de B utilizando como fonte o ácido bórico (alta solubilidade, 17% B) ou1 kg ha-1 de B utilizando como fonte o borogran (baixa solubilidade, 10% B), aplicados no sulco de plantio, com ou sem aplicações de ácido bórico via foliar na dose de 0,5% de ácido bórico na calda com volume de 250 L ha-1. Com a omissão de B via foliar houve incremento em altura de plantas nos tratamentos que receberam a aplicação do micronutriente no plantio, diferindo significativamente da testemunha. Porém, ambas as fontes, independente da solubilidade, apresentaram resultados semelhantes. As duas aplicações de B via foliar foram suficientes para que houvesse...

Doses of N, P and K in the cultivation of eucalyptus in soil originally under Cerrado vegetation / Doses de N, P e K na cultura do eucalipto em solo originalmente sob Cerrado

Many eucalyptus plantations in Brazil are in areas of soil with low fertility, with little phosphorous (P) and potassium (K) availability and with low organic matter (OM) content, resulting in a low supply of nutrients to plants, directly reflected in reduced yield. Thus, our objective was to evaluate the effects of nitrogen (N), P and K fertilization on the growth of eucalyptus plants, with the aim of achieving nutritional balance and high yield. The experiment was conducted on Renascença Farm, an agricultural property administered by Cargill Agrícola S.A., located in the city of Três Lagoas, Mato Grosso do Sul state, Brazil. The experimental design consisted of randomized blocks with ten treatments and five replicates. The treatments were composed of doses of N (0, 70, 105 and 140 kg ha-1), doses of P (0,40, 70 and 100 kg ha-1 of P2O5) and doses of K (0, 90, 135 and 180 kg ha-1 of K2O). The doses of N and K were applied at planting and as top dressing, and the doses of P were applied only at planting. The diameter at breast height (DBH), plant height and timber volume with bark were assessed, and the concentrations of macronutrients in the leaves were determined. DBH and volume were positively affected by N fertilization, and eucalyptus growth in DBH, height and volume increased with P and K fertilization. The maximum yield of eucalyptus at 21 months of age was obtained with the application of71 kg ha-1 of N, 100 kg ha-1 of P2O5 and 125 kg ha-1 of K2O. The concentrations of macronutrients wereadequate even in the absence of the application of N, P and K. With increasing doses of K, there was an increase in leaf concentrations of K and a decrease in those of calcium and magnesium.(AU)

Grande parte do plantio da cultura do eucalipto no Brasil encontra-se em área de solo de baixa fertilidade, com pouca disponibilidade de fósforo (P) e potássio (K), e baixo teor de matéria orgânica (M.O.), o que implica em baixo fornecimento de nutrientes à planta, refletindo diretamente na redução da produtividade. Neste sentido, objetivou-se avaliar a adubação nitrogenada, fosfatada e potássica no crescimento das plantas de eucalipto visando equilíbrio nutricional e alta produtividade. O experimento foi executado na Fazenda Renascença, fundo agrícola administrado pela Cargill Agrícola S/A, localizado no município de Três Lagoas/MS. O delineamento experimental foi o de blocos casualizados com dez tratamentos e cinco repetições. Os tratamentos foram constituídos por doses de nitrogênio (N) (0, 70, 105 e 140 kg ha-1), doses de P (0, 40, 70 e 100 kg ha-1 de P2O5) e doses de K (0, 90, 135 e 180 kg ha-1 de K2O). As doses de N e K foram aplicadas no plantio e em cobertura e as doses de P somente no plantio. Foram avaliados: o diâmetro à altura do peito (DAP), a altura de plantas, o volume de madeira com casca e determinados as concentrações de macronutrientes nas folhas. O DAP e o volume foram influenciados positivamente pela fertilização nitrogenada, já o crescimento do eucalipto em DAP, a altura e o volume aumentaram com a adubação fosfatada e potássica. A máxima produtividade do eucalipto aos 21 meses de idade foi obtida com aplicação de 71 kg ha-1 de N, 100 kg ha-1 de P2O5 e 125 kg ha-1 de K2O. As concentrações dos macronutrientes estiveram adequadas mesmo na ausência da aplicação de N, P e K. Com o aumento das doses de K houve incremento das concentrações foliares de K e diminuição das de cálcio e magnésio.(AU)