Abstract The application of methyl jasmonate and mechanical stimuli seem to modulate morphological characteristics that are to ensure survival under adverse environmental conditions. The study aimed to evaluate morphological characteristics of woody species rustified with methyl jasmonate and stem bending under water restriction. Seedlings of Inga sessilis and Nectandra grandiflora were hardened with pulverization of 50 μmol L-1 of methyl jasmonato, 20 stem bending daily and the control treatment for eight weeks. Afterwards, they were transplanted in vessels containing sand and submitted to water restriction for a month, being evaluated biweekly parameters such as increments of height (IH), diameter (IDC), leaf area (AF), leaf dry mass (MSF), stem dry mass (MSC) and root dry mass (MSR), root regeneration potential (PRR), electrolytes at the root (PER). The design was completely randomized with seven replicates of three seedlings each. In N. grandiflora, stem bending showed lower root emission, and when submitted to water restriction reduced AF, MSF and IH, until the end of the evaluated period. For I. sessilis, at time 0 and at day 15, the stem bending expressed lower MSF in relation to jasmonate, however, both did not differ from the control. At 15th the smaller AF was observed in the seedlings treated with stem bending, as well as the lower PER tissue. At the 30th day, both hardening treatments showed lower AF and MSF, and the jasmonato showed lower MSC and MSR in relation to the control treatment. Thus, the mechanical method is not recommended for hardening of Nectandra grandiflora, and both methods, chemical - with methyl jasmonato - and the mechanic - through stem bending - did not present satisfactory results that justify its use to hardening of seedlings of Inga sessilis.

Resumo A aplicação de metil jasmonato e estímulos mecânicos parecem modular aspectos morfológicos que asseguram a sobrevivência de mudas de espécies lenhosas sob condições ambientais adversas. O estudo objetivou avaliar características morfofisiológicas de espécies lenhosas rustificadas com metil jasmonato e flexões caulinares sob restrição hídrica. Mudas de Nectandra grandiflora e Inga sessilis foram submetidas à rustificação com 50 μmol.L-1 de metil jasmonato, 20 flexões diárias e o tratamento controle, durante oito semanas. Em seguida, foram transplantadas em vasos contendo areia e submetidas à restrição hídrica durante um mês, sendo avaliadas quinzenalmente atributos, como incremento em altura de planta (IH) e diâmetro do coleto (IDC), área foliar (AF), massa seca do caule (MSC), raiz (MSR) e folhas (MSF), potencial de regeneração de raízes (PRR) e perda de eletrólitos de raíz (PER). O delineamento utilizado foi inteiramente ao acaso, com três tratamentos e sete repetições de três mudas cada. Em N. grandiflora, as flexões caulinares externaram menor emissão de raízes, e quando submetidas à restrição hídrica, reduziram-se AF, MSF e IH, até o final do período avaliado. Para I. sessilis, no tempo 0 e ao 15º dia, as flexões caulinares externaram menor MSF em relação ao metil jasmonato, no entanto, ambos não diferiram do controle. Ao 15º dia, a menor AF foi observada nas mudas tratadas com flexões caulinares, bem como a menor PER. Ao 30º dia, ambos tratamentos rustificativos demonstram menor AF e MSF, e o metil jasmonato externou menor MSC e MSR em relação ao tratamento controle. Assim, o método mecânico não é recomendado para rustificação de mudas de Nectandra grandiflora, e ambos os métodos, químico - com metil jasmonato - e o mecânico - mediante flexões caulinares - não apresentaram resultados satisfatórios que justifiquem a sua utilização para rustificação de mudas de Inga sessilis.

ABSTRACT Growth analysis (GA) is used to quantify plant development based on morphophysiological changes. GA is a practical tool to evaluate nursery techniques to make them more efficient. The objective of this essay was to quantity measure morphophysiological growth variables of Eucalyptus grandis x Eucalyptus urophylla and Hymenaea courbaril (jatoba) container seedlings to characterize growth stages. The essay was conducted in a shade house located in the western state of Paraná. GA analyses were performed at 10-day intervals on seedlings of both species. When evaluating Hymenaea courbaril seedlings results indicated increased values of height, diameter, root and shoot dry biomass up to 130 days after emergence (DAE). Seedling growth stage-based GA were 70, 100 and 130 DAE for the Eucalyptus hybrid and 50, 80, and 110 DAE for jatoba which presented accelerated, intermediate and reduced seedling growth.

ABSTRACT The forestry production sector uses several strategies to minimize post-planting seedling losses. Some practices can modulate characteristics of interest for plant growth and defense, including changes in the light exposure, reduced watering, fertilization, and chemical or mechanical stimulus. This work quantified morphophysiological changes on Schinus terebinthifolius and Cedrela fissilis seedlings resulting from the application of salicylic acid for eight weeks. The experimental design was completely randomized, composed of four treatments (0, 100, 200, and 300 mg L-1 of salicylic acid). The quantified variables included height, diameter, and dry matter mass of the root and aerial parts. Additionally, leaf area, root-cell electrolyte loss, lignin content in roots, and stem plus phenolic compounds were quantified. On aroeira seedlings, the height, aerial, and radicular dry matter masses and leaf area were reduced while the diameter and the lignin content increased directly as a function of salicylic acid doses. In cedro seedlings the dose of 100 mg L-1, however, resulted in a better balance of plant biomass and would, therefore, be the most indicated dose for the species. The application of salicylic acid for 8 weeks on seedlings of both species resulted in the most relevant morphophysiological modifications correlated with quality characteristics of seedlings of woody species.

Abstract Exogenous application of stress inductors can facilitate and accelerate some biological responses that promote plant defense. The objective of the experiment was to quantify some compounds linked to nitrogen metabolism as a function of the application of salicylic acid in Schinus terebinthifolius seedlings submitted to water deficit. The experiment was constituted of four doses of salicylic acid and three periods of water deficit. Quantifications included levels of nitrate, free ammonium, total soluble amino acids, proteins, proline, glycine-betaine and relative water content. When evaluating the relative water content in seedlings of Schinus terebinthifolius at 8 days, it was observed that the dose of 200 mg L-1. Seedlings showed physiological responses when subjected to doses of salicylic acid of 200 and 300 mg L-1. The increase in concentration of proline and glycine are advantageous, because these substances act as osmoregulators and cell protectors against deficit hydrical.

RESUMO Esta pesquisa objetivou determinar o melhor momento da colheita de sementes de Anadenanthera colubrina (Vell.) Brenan baseado na cor do fruto. Os frutos foram classificados em quatro estádios de maturação: fruto com cor verde-amarelo moderado; fruto com cor castanho-escuro; fruto com cor castanho-escuro avermelhado; e fruto com cor castanho-claro. As sementes foram avaliadas quanto às características biométricas e testadas quanto à germinação e vigor. O experimento foi conduzido em delineamento inteiramente casualizado. As médias foram comparadas pelo teste de Tukey (p ≤ 0,05). Realizou-se uma análise de correlação não paramétrica de Spearman entre os estádios de maturação e as características físicas e fisiológicas das sementes. As maiores médias de tamanho foram observadas nas sementes dos frutos com cor verde e castanho-escuro. As sementes dos frutos com cores castanho-escuro avermelhado e castanho-claro apresentaram redução drástica no teor de água, e evidenciaram alto potencial germinativo e de vigor. Observaram-se correlações fortes e negativas entre o estádio de maturação e as características físicas das sementes. Por outro lado, o acúmulo de massa seca, potencial de germinação e de emergência e os índices de vigor apresentaram correlações fortes e diretamente proporcionais ao estádio de maturação. A cor do fruto, aliada às características físicas das sementes, demonstraram-se como um bom indicador da maturidade fisiológica das sementes de Anadenanthera colubrina. Frutos com cores castanho-escuro avermelhado e castanho-claro apresentam qualidade fisiológica superior. Desse modo, o indicativo de tais colorações sugere o momento da colheita das sementes.

ABSTRACT This research aimed to determine the best time to harvest Anadenanthera colubrina (Vell.) Brenan seeds based on fruit color. The fruits were classified in four maturation stages: fruit with a moderate yellow green color; fruit with dark brown color; fruit with dark reddish-brown color; fruit with a light brown color. The seeds were evaluated for biometric characteristics and tested for germination and vigor. The experiment was conducted in a completely randomized design. The averages were compared by the Tukey test (p ≤ 0.05). A non-parametric Spearman correlation analysis was performed between maturation stages and physical and physiological characteristics of the seeds. The largest size averages were observed in seeds from fruits with green and dark brown color. Seeds from fruits with dark brown and reddish-brown color showed drastic reduction in the water content, and high germinative potential and vigor. Strong and negative correlations were observed between maturation stage and seed physical characteristics. On the other hand, the accumulation of dry mass, germination potential, emergence and vigor indexes showed strong correlations and were directly proportional to maturation stage. The color of the fruit was shown to be a good indicator of the physiological maturity of the seeds of Anadenanthera colubrina. Fruits with a reddish-brown and light brown color have superior physiological quality, and thus, indicative of time for seed harvest

RESUMO A fertilização e a rustificação durante a produção das mudas de espécies lenhosas promovem alterações morfofisiológicas que potencializam o crescimento e minimizam os danos por estresse após o plantio a campo. O experimento objetivou avaliar a fertilização nitrogenada durante a produção e quantificar as alterações na morfogênese após a aplicação de etileno em mudas de Eucalyptus grandis (Hill) ex Maiden. O experimento foi conduzido em casa de vegetação localizada sob as coordenadas 24°33’ S e 54°04’ O, em delineamento de blocos casualizados em esquema fatorial com testemunha adicional (3 x 4+1) composto por três regimes de fertilização (100 mg L-1 de N convencional, 100 mg L-1 de N exponencial e zero N) aplicados durante três meses (nove aplicações) e quatro aplicações aditivas de etileno de 1.000 mg L-1 mais uma testemunha sem aplicação do regulador vegetal com seis repetições de cinco mudas por parcela. As fertilizações, exponencial e convencional, bem como as aplicações semanais de etileno induziram alterações fisiológicas na fase de rustificação em mudas de Eucalyptus grandis. Os regimes de fertilização externaram efeitos semelhantes com duas aplicações de etileno, reduzindo a concentração de fósforo e potássio e estimulando o acúmulo de lignina na parede celular de raízes. Não houve efeito dos regimes de fertilização e das aplicações de etileno sobre a sobrevivência em mudas de Eucalyptus grandis.

ABSTRACT Fertilization and hardening during seedling production are extremely important to promote morpho-physiological changes that enhance growth and minimize the stress damage after field planting. This experiment aimed to evaluate nitrogen fertilization during production of Eucalyptus grandis (Hill) ex Maiden seedlings and to quantify morphometric changes. The experiment was conducted in a greenhouse located at 24°33 ‘S and 54°04’ W in a randomized complete block design in a factorial scheme with an additional control (3 x 4+1) composed by three regimes of fertilization (100 mg L-1 conventional N, 100 mg L-1 exponential N and zero N) applied for three months (nine applications) and four ethylene applications of 1000 mg L-1 more one control without application of plant regulator with six replicates of five plants per plot. Fertilization, both exponential or conventional, as well as the weekly application of ethylene, induced physiological changes of Eucalyptus grandis seedlings during hardening. Fertilization regimes presented similar effects with two ethylene applications, reducing phosphorus and potassium levels and stimulating the accumulation of lignin in the cell wall of roots. There was no effect of the fertilization regimes and the ethylene application on the survival of Eucalyptus grandis seedlings.

Abstract Nutritional balance interferes positively in obtaining high-quality seedlings of wood species. This study aimed to evaluate nitrogen fertilization during the production of L. divaricata seedlings. The experiment was conducted in a shade house located at 24°33’S and 54°04’W, in a randomized block design formed by two forms of fertilization plus a control applied during three months, totaling nine applications, with seven replicates of five seedlings each. Both exponential and conventional fertilization regimes supported the hypothesis of growth induction of L. divaricata seedlings in relation to the control during the growth phase, with exponential fertilization as a valid option to reduce initial nutrient loss by leaching.

Resumo O objetivo deste estudo foi identificar a cor do fruto de Albizia hasslerii que corresponde a sementes com maior potencial fisiológico. Os frutos foram colhidos em diferentes estádios de maturação para a realização das análises, sendo classificados visualmente em quatro cores: 100% verde (estádio 1), ≤ 50% marrom (estádio 2), entre 50% e 99,9% marrom (estádio 3) e 100% marrom (estádio 4). Posteriormente, procedeu-se a mensuração dos atributos biométricos das sementes, e simultaneamente, Risssos testes de germinação e vigor foram instalados. Para verificar a relação da maturação de frutos com a biometria e o potencial fisiológico de sementes, determinou-se o coeficiente de correlação de Spearman (ρ). O delineamento utilizado foi inteiramente casualizado, sendo os resultados submetidos à análise de variância, e as médias comparadas pelo teste de Tukey, a 5% de probabilidade. As sementes provenientes dos frutos que se encontravam nos estádios 3 e 4, manifestaram maior germinação e emergência, menores médias de teor de água e maior matéria seca, sendo esses indicadores do melhor momento de colheita de frutos. Já as sementes obtidas de frutos verdes apresentaram baixa germinação e vigor, alto teor de água e menor matéria seca. Conclui-se que as sementes com alto potencial fisiológico estão em frutos com cor 100% marrom, porém a partir de 50% de cor marrom já podem ser colhidos. Portanto, a cor dos frutos é considerada um indicador de maturidade fisiológica para a espécie Albizia hasslerii.

Abstract The objective of this study was to identify the color of Albizia hasslerii fruit that corresponds to seeds with high physiological potential. Fruits were harvested at different ripening stages for the analysis and were visually classified into four stages according to epicarp color: 100% green (stage 1), ≤ 50% brown (stage 2), between 50% and 99.9% brown (stage 3) and 100% brown (stage 4). Subsequently, we quantified seed biometric attributes and proceeded to install the germination and vigor tests. To verify the relationship between fruit maturation with seed biometrics and the physiological potential, we calculated the Spearman correlation coefficient (ρ). The design was a completely randomized, and the results were submitted to analysis of variance with means compared by Tukey test at 5% probability. The seeds from the fruits classified as stages 3 and 4 showed greater germination and emergence, lower averages of water content and higher dry biomass, being those indicators of the best time for the fruit harvest. The seeds from green fruits presented low germination and vigor, high water content and lower dry biomass. It was concluded that seeds with high physiological potential are from fruits with 100% brown color. However, fruits showing 50% brown color can already be harvested. Therefore, fruit color is considered an indicator of physiological maturity for Albizia hassleri.

Resumo O trabalho objetivou verificar se a rustificação por flexões caulinares e a pulverização foliar com ácido jasmônico (JA) induz lignificação e altera o desenvolvimento pós-plantio. O experimento iniciou em ambiente protegido seguindo um delineamento inteiramente ao acaso com sete tratamentos (T1) testemunha; (T2) 2,0 μmol L-1 de JA; (T3) 4,0 μmol L-1 de JA; (T4) 6,0 μmol L-1 de JA; (T5) 8,0 μmol L-1 de JA; (T6) 20 flexões; (T7) 40 flexões e cinco repetições. Ao final da aplicação dos tratamentos, avaliaram-se os incrementos na altura, no diâmetro do coleto e número de folhas, assim como o teor de lignina dos tecidos caulinares, das raízes e a rigidez flexural. Em seguida, as mudas rustificadas foram plantadas a campo em delineamento em blocos ao acaso com três mudas por repetição. Aos 90 e 150 dias, avaliaram-se os incrementos na altura e no diâmetro do caule. Mudas dos tratamentos T5 e T6 apresentaram maior resistência à curvatura (0,2885 e 0,3005 N cm-1, respectivamente). O teor de lignina no caule aumentou com aplicações de JA acima de 6,0μmol L-1 e imposição de flexões caulinares. As menores doses de JA (T2, T3 e T4) e o tratamento com 20 flexões caulinares (T6) resultaram em mudas com aumento no incremento no diâmetro do caule. A interpretação da análise de trilha demonstrou que houve aumento na rigidez do caule acompanhado com o aumento no teor de lignina e que estes possuem um maior efeito direto inversamente proporcional com o incremento médio em altura e com o diâmetro do caule após o plantio.

Abstract The objective of this work was to verify if hardening by stem bending and foliar spray of jasmonic acid (JA) induced lignification and if it altered the post-planting development. The experiment was initially conducted in a shade house following a completely randomized design with treatments as (T1) control; (T2) 2.0 μmol L-1 of JA; (T3) 4.0 μmol L-1 of JA; (T4) 6.0 μmol L-1 of JA; (T5) 8.0 μmol L-1 of JA; (T6) 20 stem bending; (T7) 40 stem bending and five replicates. At the end of the imposed treatments, we calculated the increments in height, stem diameter, number of leaves, root and shoot dry biomasses, as well as the lignin content of shoots and roots and the stem stiffness. Afterwards, seedlings were planted following a randomized block design with three seedlings per replicate. At 90 and 150 days after planting, we quantified increments in height and stem diameter. Treatments T5 and T6 showed higher bending strength (0.28885 and 0.3005 N cm-1, respectively). Seedlings submitted to doses above 6.0 μmol L-1 of JA (T5) and imposition of stem bending (T6 and T7) resulted in a higher stem lignin content. The smaller doses of JA (T2, T3 and T4) and 20 stem bending (T6) resulted in seedlings with a relative increase in diameter. The interpretation of path analysis showed weak multicollinearity, that is, the variables under study are not highly correlated and there was a greater direct correlation between the lignin content of the stem with the mean increase in height and diameter of the seedlings after planting.

Abstract This study aimed to quantify the effects of water management during hardening on seedlings of Gallesia integrifolia (Spreng.) Harms, evaluating leaf temperature, morphometric variables, and their performance after hardening in sandy and clayey soil. Water regimes included irrigation for four weeks (daily, every two, three, and four days). Leaf temperature was recorded at the end of each irrigation cycle. Increases in height, root collar diameter, root dry mass, and aerial part dry mass were measured at the end of the hardening period. The seedlings irrigated every two and three days did not significantly differ (p > 0.05) from those irrigated daily. Irrigation every four days reduced the speed of aboveground growth and increased leaf temperature. The seedlings irrigated every three and four days were more resistant to water deficit than those from other treatments, showing severe symptoms of water deficit later.

Resumo Este trabalho objetivou investigar as respostas fotossintéticas em mudas de híbrido 1528 de Eucalyptus urophylla x Eucalyptus grandis submetidas à aplicação de ácido jasmônico (JA) e flexões caulinares. O experimento foi conduzido em casa de sombra utilizando delineamento inteiramente ao acaso com cinco repetições de 20 mudas, com os seguintes tratamentos: T1: controle, T2: 8,0 µmol de JA e T3: 40 flexões caulinares. A taxa de assimilação líquida de CO2 (A), condutância estomática (gs), concentração interna de CO2 (Ci), taxa de transpiração da folha (E), eficiência do uso de água (WUE), eficiência intrínseca do uso de água (iWUE) e eficiência de carboxilação (Fc) foram mensuradas com o auxílio do IRGA. A dose de JA aplicada nas mudas foi insuficiente para alterar as respostas fotossintéticas em relação ao tratamento-controle. Estímulos mecânicos induzidos através de flexões caulinares em mudas do híbrido 1528 de eucalipto promoveram incremento da capacidade fotossintética máxima e máxima assimilação de CO2. Porém, as mudas apresentaram redução na eficiência do uso da água, ou seja, menor eficiência fotossintética quando comparado com as mudas submetidas aos demais tratamentos. Mudas do híbrido 1528 de eucalipto submetidas aos estímulos mecânico e ácido jasmônico apresentaram maior respiração sob níveis baixos de fluxo de fótons fotossinteticamente ativos.

Abstract This work aimed to investigate the photosynthetic responses of Eucalyptus urophylla x Eucalyptus grandis hybrids 1528 submitted to the application of jasmonic acid (JA) and stem bending. The experiment was conducted in a shade house using a completely randomized design with five replicates of 20 seedlings, with the following treatments: T1: control, T2: 8.0 µmol of JA and T3: 40 stem bending. The net assimilation rate of CO2 (A), stomatal conductance (gs), internal CO2 concentration (Ci), leaf transpiration rate (E), water use efficiency (WUE), intrinsic efficiency of use of Water (iWUE) and carboxylation efficiency (Fc) were measured with an IRGA. The dose of JA applied to the seedlings was insufficient to alter the photosynthetic responses in relation to the control treatment. Mechanical stimuli induced by stem bending in eucalyptus hybrid 1528 seedlings promoted an increase in the maximum photosynthetic capacity and maximum assimilation of CO2, but the seedlings presented a reduction in the efficiency of the water use, that is, lower photosynthetic efficiency when compared to the seedlings submitted to other treatments. Seedlings of eucalyptus hybrid 1528 submitted to mechanical stimuli and jasmonic acid show greater respiration under low flow levels of photosynthetically active photons.

RESUMO Estudar o comportamento fisiológico e bioquímico de sementes de Myrcianthes pungens armazenadas em diferentes embalagens por até dez meses foi o objetivo deste trabalho. Sementes foram coletadas em Toledo, Pato Bragado e Marechal Cândido Rondon e armazenadas em câmara fria e seca (11 ºC e 6,3% UR) por dez meses. A cada avaliação além da determinação do teor de água, foram realizados teste de germinação (TG) e vigor índice de velocidade de germinação (IVG), comprimento de plântulas (CP) e massa de matéria seca de plântulas (MSP) e teste de tetrazólio (TZ). Utilizou-se a análise não paramétrica. Durante o armazenamento, o teor de água das sementes nas embalagens de plástico e vidro variou pouco, no entanto decresceu na embalagem de papel. A germinação manteve-se até os dez meses quando as sementes foram armazenadas em embalagens de plástico e por dois meses nas de vidro e papel. As variáveis IVG, CP e MSP apresentaram acréscimos e decréscimos ao longo do armazenamento. O TZ revelou que na embalagem de as sementes permaneceram viáveis até os dez meses, no vidro até dois meses e no papel até quatro meses. Sementes de Myrcianthes pungens com elevada qualidade inicial podem ser armazenadas em câmara fria e seca em sacos plásticos, mantendo a viabilidade e vigor pelo período de dez meses.

ABSTRACT Studying the physiological and biochemical behavior of Myrcianthes pungens seeds stored in different packages for up to ten months was the objective of this work. Seeds were collected in Toledo, Pato Bragado, and Marechal Cândido Rondon and stored in a cold and dry chamber (11 ºC and 6,3% RH) for ten months. The germination test and the germination speed index (GSI), the seedling length (SL), the seedling dry matter mass (DMS), and the tetrazolium (ZT) test were performed and, for each evaluation, the water content was determined. Non-parametric analysis was used. During storage, the water content of the seeds in the plastic and glass containers varied little, but decreased in the paper packaging. The germination was maintained for ten months when the seeds were stored in plastic containers and for two months in the glass and paper ones. The variables GSI, SL, and DMS presented upwards and downwards variations during the storage period. The ZT revealed that, in the plastic packaging, the seeds remained viable for up to ten months, in glass, up to two months, and in paper, up to four months. Therefore, seeds of Myrcianthes pungens with high initial quality can be stored in a cold and dry chamber in plastic bags, maintaining viability and vigor for a period of ten months

RESUMO O presente trabalho objetivou quantificar os efeitos da tigmomorfogênese induzida por flexões caulinares na fase de rustificação de mudas de Pinus taeda L. sobre a partição da matéria seca e de carbono. Mudas de Pinus taeda com 22 cm de altura, produzidas em tubetes, foram submetidas a cinco intensidades de flexões caulinares (0, 5, 10, 20 e 40 flexões) realizadas diariamente, com o auxílio de um aparato mecânico, por 60 dias. Ao final, quantificou-se a área foliar e os incrementos na altura e no diâmetro do coleto. Posteriormente, determinaram-se os incrementos na massa de matéria seca de raízes e da parte aérea foram subdivididas em cinco componentes: raiz pivotante, raízes laterais, acículas, casca e lenho. Na matéria seca resultante, foi determinado o teor e conteúdo de carbono. O experimento seguiu o delineamento inteiramente ao acaso com quatro repetições. Os resultados foram submetidos à análise de regressão a 5% de probabilidade de erro. A tigmomorfogênese induzida por flexões caulinares resultou na redução do crescimento em altura, área foliar e matéria seca da parte aérea, mas, com até 20 flexões caulinares, promoveu o aumento da taxa de crescimento em diâmetro e matéria seca do sistema radicular. A alteração no crescimento primário e secundário foi resultante da redistribuição de carbono e do conteúdo de matéria seca no caule e no sistema radicular, principalmente em raízes laterais, através de redução de área foliar. Os resultados sugerem que em mudas perturbadas mecanicamente o aumento em área foliar deixa de ser o dreno preferencial de carbono, predominando o crescimento de caule e sistema radicular.

ABSTRACT The present study aimed at quantifying the effects of thigmomorphogenesis induced by stem bending in the hardening phase of seedlings of Pinus taeda L. on the partitioning of dry matter and carbon. Seedlings of Pinus taeda 22 cm high grown in tubes were subjected to five intensities of stem bendings (0, 5, 10, 20 and 40 bendings) performed daily using a mechanical device, for 60 days. Subsequently we quantified the leaf area and the increments in height and diameter. Afterwards, it was determined the increments in dry weight of roots and shoots, which were subdivided into five components: taproot, lateral roots, needles, bark and wood. Along with the resulting dry matter, we determined the carbon concentration and content. The experiment followed a completely randomized design with four replications. The obtained data were subjected to regression analysis at 5% error probability. The thigmomorphogenesis induced by stem bendings resulted in a reduced height growth, leaf area and shoot dry weight, but with up to 20 stem bendings increased the growth rate in diameter and the root dry weight. The changes in primary and secondary growth was a result of the redistribution of carbon and dry matter content in the stem and root system, especially in lateral roots through of reduced leaf area, in terms of area and dry matter. The results suggest that on mechanically disturbed seedlings increase in leaf area ceases to be the preferred sink of carbon, predominating the growth of stem and root.

RESUMO Para o sucesso do plantio a campo e o êxito de um povoamento florestal, faz-se necessário o uso de mudas florestais que apresentem bom desempenho após o plantio. Este estudo objetivou avaliar a qualidade de mudas de eucalipto, após rustificação com aplicação de ácido jasmônico (JA) e flexões caulinares. O experimento foi realizado em duas etapas, sendo a primeira desenvolvida em ambiente protegido e a segunda realizada a campo. O delineamento experimental foi inteiramente ao acaso, com sete tratamentos (testemunha; 2,0; 4,0; 6,0 e 8,0 μmol L-1 de JA, aplicados semanalmente, por quatro semanas; 20 e 40 flexões caulinares diárias, por quatro semanas), com cinco repetições. Após as quatro semanas de aplicação dos tratamentos, foram determinados os incrementos de altura, de diâmetro do coleto e de número de folhas, de massas de matérias secas das raízes e da parte aérea, de potencial de regeneração de raízes e de índice SPAD. Aos 90 dias após o plantio, foram avaliados os incrementos de altura e de diâmetro do coleto e a relação altura/diâmetro das mudas. A análise de agrupamento por UPGMA evidenciou a formação de três grupos: grupo 1 (testemunha, 2,0; 4,0 e 6,0 μmol L-1 de JA); grupo 2 (8,0 μmol L-1 de JA) e grupo 3 (flexões caulinares). Mudas que apresentaram maior incremento de altura e de número de folhas (grupos I e II), durante a fase de rustificação, apresentaram maiores incrementos de altura e de diâmetro do coleto a campo, aos 90 dias após o plantio. Parâmetros como incrementos de diâmetro do coleto, de potencial de regeneração de raízes e de SPAD, quantificados durante a rustificação de mudas no viveiro, não são preditivos de maior desempenho a campo.

ABSTRACT The objective of this work was to evaluate the quality of seedlings of clone 1528 of eucalyptus after hardening with application of jasmonic acid (JA) and stem bending. The experiment conducted in two stages, the first in protected environment and the second in the field. A completely randomized experimental design with seven treatments (control, 2.0, 4.0, 6.0 and 8.0 μmol L-1 of JA applied weekly for 4 weeks, 20 and 40 daily push-ups for 4 weeks), with five replicates of twenty seedlings. At the end of the treatments, the increase in height (IA), collection diameter (IDC), number of leaves (NF), dry masses of roots and shoot and relative chlorophyll index (SPAD) were determined. At 90 days after planting (field), the increases in height, the collection diameter, and the height / diameter ratio of the seedlings were evaluated. A clustering analysis by UPGMA showed a formation of three groups: group 1 (control, 2.0, 4.0 and 6.0 μmol L-1 of JA); Group 2 (8.0 μmol L-1 of JA) and group 3 (stem bending). Seedlings that showed the greatest increase in height and number of leaves (groups I and II) during the rustification phase obtained to greater increase in height and in the diameter of the field collection at ninety days after planting. Parameters such as increment in collection diameter, root regeneration potential and SPAD quantified during the rustification of seedlings in the nursery are not predictive of higher field performance.

ABSTRACT Seed deterioration is a natural and irreversible process. Nevertheless, seed priming with water and antioxidants can minimize oxidative damage in oilseeds, resulting in attenuation of seed deterioration. The objective of this assay was to evaluate seed priming on respiratory activity of Jatropha curcas submitted to accelerated aging. Seeds from two provenances (Janauba and Pedro J. Caballero) were submitted to three priming treatments (control, immersion in deionized water, and with 750 µmol L-1 of ascorbic acid) and treated for accelerated aging at 41 °C for 72 h. The results showed that the priming of J. curcas seeds promoted tolerance to accelerated aging. Primed seeds, with ascorbic acid from Janauba and deionized water from Pedro J. Caballero, resulted in a higher percentage of normal seedlings, and increased germination speed index and seed respiration. The decline of physiological quality of J. curcas seeds after accelerated aging is directly associated with a reduction in respiratory activity that is related to seed moisture content.