ABSTRACT: In Brazil, the optimal dose of phosphorus in the cultivation of yerba mate (Ilex paraguariensis St. Hil.) clones has yet to be defined. This study verified the productivity of yerba mate clones in response to the application of P doses and determined the critical level of the nutrient in soil and yerba mate leaves. The experiment was developed in Itaiópolis-SC, in humic cambisol, from 2013 to 2020. Five doses of the nutrient were evaluated in two clones (BRS-BLD Aupaba and F2) of yerba mate. Fertility was defined by planting/post-planting (0, 2.3; 4.5; 6.8, and 9.0 g plant-1), canopy formation 1 (0, 10, 20, 30, 40, and 50 g plant-1), canopy formation 2 (0, 15, 30, 45, and 60 g plant-1), and production (0, 16.7; 33.3; 50.0; 66.7 kg ha-1). Harvests took place between July 2015 and January 2020, at 18-month intervals. The productivity of leaves, fine branches, and thick branches was evaluated. In the 2020 harvest, soil and leaf samples were collected to determine the critical level of P. The productivity of clone components increased with phosphate fertilization in all evaluated harvests. The critical levels of P for clones, Aupaba and F2, were 5.2 and 6.3 mg dm-3 in soil and 1.03 and 1.11 g kg-1 in leaves, respectively. Yerba mate is demanding of P, expressing maximum productivity in the planting phase, canopy formation 1 and 2, and production when doses of 5, 25, 40 g plant-1, and 35 kg ha-1 of P2O5 are applied, respectively.

RESUMO: No Brasil, a dose de fósforo no cultivo de clones de erva-mate ainda não está definida. O objetivo do estudo foi verificar a produtividade de clones de erva-mate em resposta a aplicação de doses de P e determinar o nível crítico do nutriente no solo e folhas de erva-mate. O experimento foi implantado em Itaiópolis-SC, em Cambissolo Húmico, em 2013. Foram avaliadas cinco doses do nutriente em dois clones (BRS-BLD Aupaba e F2) de erva-mate. As adubações foram definidas como de plantio/pós-plantio (0, 2,3; 4,5; 6,8 e 9,0 g planta-1), formação de copa 1 (0, 10, 20, 30, 40 e 50 g planta-1), formação de copa 2 (0, 15, 30, 45 e 60 g planta-1) e produção (0, 16,7; 33,3; 50,0; 66,7 kg ha-1). As colheitas ocorreram entre julho de 2015 e janeiro de 2020, com intervalos de 18 meses. Avaliou-se produtividade de folhas, galhos finos e galhos grossos. Na safra de 2020, foram coletadas amostras de solo e folhas para determinação do nível crítico de P. A produtividade dos componentes dos clones aumentou com a adubação fosfatada em todas as safras avaliadas. Os níveis críticos de P para os clones Aupaba e F2 foram 5,2 e 6,3 mg dm-3 no solo e 1,03 e 1,11 g kg-1 nas folhas, respectivamente. A erva-mate é exigente em P, expressando produtividade máxima na fase de plantio, formação de copa 1 e 2 e produção, quando aplicado doses de P2O5 em torno de 5, 25, 40 g planta-1 e 35 kg ha-1, respectivamente.

ABSTRACT Despite the great economic importance of yerba mate (Ilex paraguariensis A. St.-Hil.), information about clonal plantations and planting conditions of this tree is still scarce. Thus, we evaluated initial field establishment of five clonal yerba mate cultivars, planted at three seasons of the year (summer, autumn, and spring) in a shaded environment, and in the autumn, we also established blocks in a full sunlight environment, to compare both cultivation environments. We evaluated plants at 3, 6, 9, and 12 months after planting, counting the surviving plants, shoots number, and measuring height and canopy diameter. At 12 months we also analyzed the caffeoylquinic acids (CQA) contents in mature leaves from different environments. Plant survival and growth were not affected by planting seasons. Cultivars Aupaba and BRS 409 had the highest survival rates in all seasons evaluated. The shaded environment provided greater survival and growth than full sunlight, also showing higher CQA levels in the leaves. Clonal cultivars Aupaba, BRS 408, and BRS 409 presented higher growth in both environments. The severe drought in the first year may have affected survival; however, growth was considered satisfactory and plants’ initial establishment was better in the shaded environment.

Abstract The development of vegetative propagation programs of Araucaria angustifolia still lacks on information about genetic factor that may influence on its success. We aimed to evaluate how mother tree sex and provenance influence on grafting success. So, we collected orthotropic branches from 26 mother trees male and female, of a clonal garden established from matrices from different provenances, and carried out an experiment using a patch grafting technique. Grafting survival, number and length of shoots did not differ between mother tree sex and provenance. The absence of significant variations between mother trees and no correlation with sex or provenance indicates that the morphological characteristics of rootstocks and shoots, and environmental conditions after grafting may have more influence on the success of grafting.

Resumo O objetivo deste trabalho foi avaliar os compostos bioativos e a anatomia foliar de morfotipos de erva-mate (Ilex paraguariensis). A capacidade antioxidante, os compostos fenólicos totais, as metilxantinas e os ácidos cafeoilquínicos foram determinados a partir do extrato aquoso das folhas dos seguintes morfotipos de erva-mate: sassafrás, verde-escuro, verde fosco, cinza e peludinha. A microscopia de luz e a microscopia eletrônica de varredura foram utilizadas para observar a diferenciação anatômica. O morfotipo verde-escuro apresenta os maiores teores de cafeína (20,4 mg g-1) e difere significativamente apenas do morfotipo peludinha (8,8 mg g-1). Todos os morfotipos apresentaram atividade antioxidante semelhante e alta (886,0 e 588,1 μmol de atividade antioxidante equivalente a Trolox por grama de amostra, para ABTS e DPPH, respectivamente) e elevado conteúdo de compostos fenólicos totais (73,9 mg de equivalente a ácido gálico por grama de amostra). Embora a anatomia do mesofilo da folha seja semelhante, a deposição de cera e a configuração do estriamento da cutícula na superfície adaxial diferem entre os cinco morfotipos.

Abstract The objective of this work was to evaluate the bioactive compounds and foliar anatomy of yerba mate (Ilex paraguariensis) morphotypes. The antioxidant capacity, total phenolic compounds, methylxanthines, and caffeoylquinic acids were determined from the aqueous extract of leaves of the following yerba mate morphotypes: “sassafras”, dark green, dull green, gray, and “peludinha”. Light microscopy and scanning electron microscopy were used to observe the anatomical differentiations. The dark-green morphotype showed the highest contents of caffeine (20.4 mg g-1), differing significantly only from the “peludinha” morphotype (8.8 mg g-1). All morphotypes showed similar and high antioxidant activity (886.0 and 588.1 μmol Trolox equivalent antioxidant activity per gram of sample for ABTS and DPPH, respectively), as well as high total phenolic compounds content (73.9 mg gallic acid equivalent per gram of sample). Although the anatomy of the leaf mesophyll is similar, the wax deposition and cuticle striation configuration on the adaxial surface differ between all five morphotypes.

Resumo Araucaria angustifolia é uma conífera nativa do Brasil de grande importância econômica. É característica da espécie a dificuldade de quebra de dominância apical e indução/crescimento de brotações múltiplas, levando a dificuldades na produção de brotações para miniestaquia e formação de copa com arquitetura mais baixa e aberta para produção de pinhão em pomares. Assim, objetivou-se avaliar a eficiência da aplicação de giberelina, o sombreamento e diferentes alturas de poda na superação da dominância apical em mudas de araucária. Mudas com aproximadamente 4 anos de idade foram submetidas a três experimentos implantados em delineamento inteiramente casualizado, sendo eles a aplicação de giberelina (0 mg L-1 GA3 e 500 mg L-1 GA3), o sombreamento (pleno sol e casa de sombra) e diferentes alturas de poda (30 cm e 60 cm) a partir do colo das mudas. A aplicação de GA3 promoveu menor número de brotações que o tratamento testemunha (0 mg L-1 GA3). Não houve influência do sombreamento no comprimento das brotações. A poda realizada a 30 cm promoveu maior número de brotações. Dessa forma, concluise que a decepa a 30 cm é indicada para produção de brotações múltiplas em A. angustifolia, não sendo necessária aplicação de GA3 e nem sombreamento das mudas para o crescimento das brotações.

Abstract Araucaria angustifolia is a native Brazilian conifer of great economic importance. The difficulty of breaking apical dominance and induction/growth of multiple shoots is characteristic of the species, leading to difficulties in the production of mini-cuttings and formation of a lower open canopy for pinion production in orchards. Thus, this study aimed to evaluate the efficiency of gibberellin application, shading and different pruning heights in overcoming the apical dominance in araucaria seedlings. Seedlings with approximately 4 years old were submitted to three experiments, which were the application of gibberellin (0 mg L-1 GA3 and 500 mg L-1 GA3); shading (full sun and shade house) and different pruning heights (30 cm and 60 cm) from the seedling neck. The application of GA3 promoted smaller number of shoots than the control treatment (0 mg L-1 GA3). There was no influence of shading on shoot length. Pruning at 30 cm promoted the largest number of shoots. Thus, it can be concluded that the cutoff at 30 cm is indicated for the production of multiple shoots in A. angustifolia, neither GA3 application nor seedling shading are necessary for shoot growth.

ABSTRACT. Grafting is an alternative method for the early production of Araucaria angustifolia seeds, and welding quality is essential for the success of the technique. The objective of this study was to create a classification of welding quality to estimate the percentage of scion survival. The patch and flute grafting techniques were used in a greenhouse and in the field. Survival was evaluated 270 days after grafting (DAG). At 60 DAG, observations of the graft connection region were made with the naked eye, classifying the connections into four welding classes. After 160 DAG, transverse cuts were performed on each class and visually and anatomically evaluated. Flute grafting presented higher initial survival (79%), but at 180 DAG, the survival rate of both techniques was similar (48% for flute and 41% for patch). There was greater scion survival for the class that had only two regions in contact with discontinuity in the bark. Stabilization of survival occurred after 180 DAG, regardless of the welding class. Visually, there were differences in welding quality; however, anatomically, all classes presented vascular connections. The visual welding quality assessment underestimated the percentage of scion survival. However, the vascular connection and development of parenchymatous tissue are promising for diagnosing grafting success.

ABSTRACT The usual propagation method for Dalbergia nigra is via seedings; however, the seasonal supply has a variable quantity of seeds which limits the continuous production of seedlings. Therefore, the objective of this study was to establish a vegetative propagation protocol via mini-cuttings technique for D. nigra from juvenile shoots obtained from seedlings. The experimental design was completely randomized in a 2 x 2 x 4 factorial scheme, with two geographical origins: two controlled release fertilizer doses (4.0 and 8.0 g.dm-³) and four indole-3-butyric acid (IBA) concentrations (0; 2,000; 4,000; and 6,000 mg.Kg-1), with four replications. The mini-cuttings were removed from the tubes after 60 days of propagation in the greenhouse, and the substrate was completely removed by washing in running water to observe the roots. The survival percentage, rooting, rooting speed and variables related to mini-cuttings vigor (largest root length (RL, cm.plant-1), number of roots (NR), surface area (SA, mm2), root volume (RV, mm³) and root dry mass (RDM, g.plant-1) were measured. The results indicated that D. nigra has an aptitude for vegetative propagation by mini-cuttings with survival values and rooting greater than 70%. Geographical origins present a different set of responses for survival, rooting and vigor of mini-cuttings. Stock plant nutrition influences mini-cuttings root growth. IBA concentrations did not promote an effect on the mini-cuttings rooting percentage; however, exogenous auxin at the dose of 6,000 mg.Kg-1 provided mini-cuttings with greater vigor in their radical system. Nonetheless, further research is suggested to define the feasibility of using this regulator in the vegetative propagation of this species.

SUMMARY: Plants producing fruits for many months of the year, or at times when few species bear fruits, are highly valuable for restoration of degraded ecosystems due to their ability to attract and support dispersing fauna. An example of this are native fig trees such as Ficus enormis. Thus, in view of the difficulties for F. enormis seedlings production, we aimed at developing a method of cuttings propagation by evaluating the rooting and root vigor of cuttings from a field clonal garden. The experiment was established between June/2015 and May/2016 at Laboratory of Forest Species Propagation of Embrapa Florestas, in Colombo-PR. We evaluated collection of cuttings during three seasons (winter, spring and summer) and application of concentrations of indole-3-butyric acid - IBA (0, 1000, 2000, 3000, 4000, 5000 mg L-1). After 45 days of cuttings establishment in an acclimatized greenhouse, the best results for rooting, number of roots, average length of the three largest roots per cutting and maintenance of leaves and shoots were found in spring and summer. Using plant regulator did not influence the rooting or root vigor of propagules; the time of the year was the predominant factor to induce rooting. The results show that the cuttings technique with propagules from a clonal garden is efficient for producing F. enormis plants and can serve as a basis for the species propagation.

RESUMEN: Las plantas que producen frutos durante muchos meses del año, o en momentos en que pocas especies dan frutos, son de gran valor para la restauración de ecosistemas degradados debido a su capacidad para atraer y apoyar la fauna dispersora. Un ejemplo de esto son las higueras nativas como Ficus enormis. Por las dificultades para la producción de plántulas de F. enormis, fue evaluada la propagación de esquejes mediante enraizamiento y vigor de sus raíces de un jardín clonal de campo. El experimento se estableció entre junio/2015 y mayo/2016 en el Laboratorio de Propagación de Especies Forestales de Embrapa Florestas, en Colombo-PR. Se evaluó la recolección de esquejes durante tres estaciones (invierno, primavera y verano) y la aplicación de concentraciones de ácido indol-3-butírico - IBA (0, 1000, 2000, 3000, 4000, 5000 mg L-1). Después de 45 días de establecimiento de esquejes en un invernadero climatizado, los mejores resultados para el enraizamiento, el número de raíces, la longitud promedio de las tres raíces más grandes por corte, el mantenimiento de las hojas y los brotes se encontraron en primavera y verano. El uso del regulador de la planta no influyó en el enraizamiento y el vigor de las raíces de los propágulos, y la época del año fue el factor predominante para inducir el enraizamiento. Los resultados muestran que la técnica de esquejes con propágulos de un jardín clonal es eficiente para producir plantas de F. enormis y puede servir como base para la propagación de esta especie.

ABSTRACT Grafting technique has been presented as an alternative for Araucaria angustifolia propagation. However, vegetative rescuing mature trees and obtaining large numbers of propagules is difficult, because the use of branch grafts has not been indicated due to its plagiotropic and morphogenic characteristic, generally resulting in undesired growth of the graft. So we aimed to describe the unpublished fact occurred in four plants of A. angustifolia grafted with grafts from primary branches that resulted in conversion to trunk. Plant growth and morphology were evaluated ten years after grafting. We verified vertical growth and organization of trunk and persistent branches with defined whorls, same to plants grafted with trunk grafts. Field tests with grafted plants using grafts obtained from the four plants resulted in same development pattern, proving the permanent morphogenic change and opening new perspectives for araucaria vegetative rescue and grafting. We concluded that trunciform shoots can be obtained by A. angustifolia grafting with plagiotropic primary branches. Despite the morphological clarity of trunciform shoots on grafted plagiotropic primary branches, it has not yet been possible to identify the causes of this reversion.

Resumo: O objetivo deste trabalho foi avaliar a sobrevivência e o crescimento inicial, no campo, de mudas de eucalipto produzidas em diferentes substratos. Mudas de Eucalyptus benthamii produzidas em 36 substratos foram avaliadas em campo. Os substratos consistiram em misturas, em diferentes proporções volumétricas, de: casca de arroz carbonizada, carvão com granulometria entre 1,0-3,0 mm, carvão com granulometria entre 3,0-5,0 mm, fibra de coco, casca de pinheiro semidecomposta, vermiculita fina, lodo de esgoto e turfa. Aos 1, 2, 3, 6, 12, 18 e 24 meses após o plantio, foram determinados sobrevivência, altura e diâmetro. Aos 24 meses após o plantio, também foram medidos incremento em altura, incremento em diâmetro, área transversal e área basal. As plântulas que apresentaram sobrevivência de 100% após 24 meses em condições de campo foram aquelas cultivadas, no viveiro, em substratos com maior proporção de vermiculita fina, lodo de esgoto e turfa, ou seja, em substratos com maior microporosidade. No entanto, não há efeito das características do substrato no crescimento inicial das plântulas. Há correlação significativa entre a sobrevivência da plântula aos 6 meses de idade e seu diâmetro no final da fase de viveiro, o que ressalta a importância desta característica para o estabelecimento da planta em campo, independentemente do substrato utilizado.

Abstract: The objective of this work was to evaluate the survival and initial growth, in the field, of eucalyptus seedlings produced in different substrates. Eucalyptus benthamii seedlings produced in 36 substrates were evaluated in the field. The substrates consisted of mixtures, at different volumetric proportions, of: carbonized rice husk, charcoal with granulometry between 1.0-3.0 mm, charcoal with granulometry between 3.0-5.0 mm, coconut fiber, semi-decomposed pine bark, fine vermiculite, sewage sludge, and peat moss. At 1, 2, 3, 6, 12, 18, and 24 months after planting, survival, height, and diameter were determined. At 24 months after planting, height increment, diameter increment, transversal area, and basal area were also measured. The seedlings that showed 100% survival after 24 months under field conditions were those grown in the nursery in substrates with a higher proportion of fine vermiculite, sewage sludge, and peat moss, that is, in substrates with a higher microporosity. However, there is no effect of substrate characteristics on seedling initial growth in the field. A significant correlation is observed between the survival of seedlings at 6 months and their diameter at the end of the nursery period, evidencing the importance of this characteristic for the establishment of the plant in the field, regardless of the used substrate.

Resumo: O objetivo deste trabalho foi avaliar o efeito do armazenamento na qualidade fisiológica de sementes de cedro (Cedrela fissilis), bem como correlacionar a germinação e o vigor das sementes com suas principais alterações bioquímicas. Os experimentos foram conduzidos em delineamento inteiramente casualizado, em arranjo fatorial 3×5 (três ambientes × cinco períodos de armazenamento). As sementes foram armazenadas por 0, 135, 280, 381 e 515 dias, em: câmara úmida a 5±2ºC e 80% de umidade relativa, câmara seca a 20±2ºC e 60% de umidade relativa e ambiente não controlado (laboratório) a 16±10ºC e 60±25% de umidade relativa. Em todos os períodos de armazenamento, foram avaliados o teor de umidade em base úmida e as percentagens de proteínas, lipídios, carboidratos totais e cinzas. Para os testes de viabilidade e vigor, foram calculados percentagem de germinação e tempo médio de germinação. No momento da coleta, as sementes apresentaram 11,5% de água, 85,5% de germinação e tempo médio de germinação de 13,5 dias, e todas foram negativamente influenciadas pelo período de armazenamento. A percentagem de proteína mostrou tendência de queda, enquanto a de carboidratos aumentou com o aumento do período de armazenamento. A germinação e o vigor das sementes reduzem drasticamente com o armazenamento.

Abstract: The objective of this work was to evaluate the effect of storage on the physiological quality of cedar (Cedrela fissilis) seeds, as well as to correlate the germination and vigor of the seeds with their main biochemical changes. The experiments were carried out in a completely randomized design, in a 3×5 factorial arrangement (three environments × five storage periods). Seeds were stored for 0, 135, 280, 381, and 515 days in: a humidity chamber at 5±2ºC and 80% relative humidity, a drying chamber at 20±2ºC and 60% relative humidity, and an uncontrolled environment (laboratory) at 16±10ºC and 60±25% relative humidity. In all storage periods, the content of moisture on a wet basis and the percentages of proteins, lipids, total carbohydrates, and ash were evaluated. For the viability and vigor tests, the percentage of germination and mean germination time were calculated. At sampling time, seeds showed 11.5% water content, 85.5% germination, and mean germination time of 13.5 days, and all were negatively influenced by storage period. Protein percentage showed a downward trend, while that of carbohydrates increased as the storage period was extended. Seed germination and vigor reduce drastically with storage.

Resumo: O objetivo deste trabalho foi avaliar a enxertia de Araucaria angustifolia em dois volumes de recipientes e três alturas. Porta-enxertos com 30±5,0 cm foram enxertados com borbulhas com 4,0±1,0 cm em tubos de plástico (recipientes) de 110 e 280 cm3, em três alturas (5,0±1,0, 10±1,0 e 15±1,0 cm). Houve redução na sobrevivência dos enxertos com o aumento da altura de enxertia, e o menor volume limitou o desenvolvimento do sistema radicular. Portanto, a enxertia a 5,0±1,0 cm em recipientes de 280 cm3 traz novas perspectivas para o aprimoramento da silvicultura clonal da espécie, com redução significativa no tempo de produção de mudas (de até 12 meses), bem como nos custos de produção, nos materiais utilizados e na área física.

Abstract: The objective of this work was to evaluate the grafting of Araucaria angustifolia in two container volumes and at three heights. Rootstocks with 30±5.0 cm were grafted with 4.0±1.0-cm buds in 110 and 280-cm3 plastic tubes (containers) at three heights (5.0±1.0, 10±1.0, and 15±1.0 cm). There was a reduction in graft survival as the height of the grafting point increased, and the lower volume limited the development of the root system. Therefore, grafting at 5.0±1.0 cm in 280-cm3 containers brings new perspectives to improve the clonal forestry of the species, with a significant reduction in plants production time (of up to 12 months), as well as in production costs, used materials, and physical area.

Abstract Our study sought to evaluate the rooting capacity of indole butyric acid (IBA)-treated stem cuttings and the efficiency of the vegetative rescue technique of adult and transitional parent trees of Lecythis pisonis. Softwood, hardwood, and semi-hardwood leafless cuttings treated with IBA (0; 2,000; 4,000; 6,000; and 8,000 mg kg-1) were tested in a randomized block design with four replicates and 10 cuttings per plot. The growth of epicormic shoots was also evaluated in 60-cm branches removed from the tree canopy and kept in greenhouse for 60 days. Cuttings from adult trees did not form roots. Softwood cuttings from transitional trees had a very low rooting percentage. In both cases, no influence of IBA concentrations were observed. The use of the sectioned-branch technique was feasible for inducing sprouts.

Resumo Na erva-mate (Ilex paraguariensis) o principal produto colhido é composto por folhas (FO) e galhos finos (GF), resultando em elevada exportação de nutrientes, dentre eles o N. As informações técnico-científicas disponíveis para subsidiar uma recomendação da adubação nitrogenada racional são insuficientes, o que põe em risco a sustentabilidade da produção, especialmente se as colheitas são mais intensivas. Por isso, objetivou-se avaliar a influência da adubação nitrogenada e do intervalo de colheita no teor de N e carbono orgânico (CO) do solo, na produtividade e no estado nutricional da erva-mate. O experimento foi instalado em São Mateus do Sul - PR, em erval com sete anos e meio de idade, estabelecido em Latossolo Vermelho Distrófico, no qual se avaliaram doses de 0, 20, 40, 80, 160 e 320 kg ha-1 de N, para intervalos de colheita de 12, 18 e 24 meses. Os teores de N e CO do solo, nas formas lábil (NL e COL) e total (NT e COT), foram determinados nas profundidades de 0-10, 10-20 e 20-40 cm. A colheita consistiu na remoção de aproximadamente 95 % da copa que brotou da colheita anterior. A massa verde colhida foi determinada individualmente para os componentes FO, GF e galho grosso (GG), sendo FO+GF correspondente à erva-mate comercial (ECOM). Avaliou-se, também, a relação entre massa verde/seca (MV/MS) e o teor de N na FO, GF e GG. O efeito positivo da adubação nitrogenada no teor de NL e COL do solo foi mais expressivo no menor intervalo de colheita e negativo ou nulo para o intervalo de 24 meses. As doses de N aumentaram o teor de NT nos maiores intervalos de colheita e reduziram para colheita de 12 meses e o COT não foi influenciado pela adubação. Houve aumento da produtividade com as doses de N, e as respostas mais expressivas ocorreram nos maiores intervalos entre colheitas. Intervalo de 12 meses entre colheitas é insuficiente para a planta recuperar-se do impacto causado pela colheita. O intervalo de 18 meses é o mais recomendável, desde que a planta esteja bem nutrida em N. A adubação nitrogenada não influencia o teor de água na erva-mate comercial verde, sendo esta dependente do intervalo de tempo entre colheitas. Teor foliar de N entre 33,0 e 37,0 g kg-1 pode indicar plantas bem nutridas, independentemente do intervalo de colheita.

Abstact Leaves (FO) and thin branches (GF) are the main plant components harvested from Ilex paraguariensis (mate) plantations, leading to high exportation of nutrients, among them, the nitrogen (N). Scientific and technical information are scarce to support fertilizer recommendation aiming to replenish N exportation and to sustain mate productivity. Thus, this study aimed to evaluate the influence of N fertilization and harvest intervals on N and organic carbon (CO) content in the soil and on mate productivity and N content. The experiment was conducted in São Mateus do Sul, Paraná state, Brazil, in a seven-year old mate plantation established on an Oxisol, where we evaluated the effect of 0, 20, 40, 80, 160, and 320 kg ha-1 of N, for harvest intervals of 12, 18, and 24 months. Nitrogen (NL) and CO (COL) in the labile and total (NT and COT) forms were determined in the soil at depths of 0-10, 10-20 and 20-40 cm. Harvest consisted in the removal of 95 % of the tree crown sprouted from the previous harvesting. The green material collected was evaluated individually for the components FO, GF and thick branches (GG), being FO+GF the commercial mate product (ECOM). We also evaluated the plant component relationships between green/dry weights (MV/MS), as well as the contents of N in FO, GF and GG. The positive effect of N fertilization on NL and COL contents in the soil was more expressive for the shortest harvesting interval, and was negative or null for the 24-month interval. Nitrogen doses increased the content of NT in the largest harvest interval and reduced the yield for 12 months; COT was not influenced by fertilization. We observed increased productivity with N doses, and the most significant responses occurred in longer harvest intervals. The interval of 12 months between harvests is insufficient for the plant recovery from the previous harvesting impacts. The 18-month interval is more recommendable because the plant is well nourished in N. Nitrogen does not affect the water content of the commercial green yerba mate, which is more affected by the time between harvests. The leaf N content between 33.0 and 37.0 g kg-1 may indicate well-nourished plants, regardless the harvest interval.

Resumo A germinação de erva-mate tem sido apontada como baixa, irregular e lenta, com diferentes graus de dormência, tornando a produção de mudas um grande desafio. Estudos destinados a esclarecer os principais mecanismos de dormência presentes em sementes de erva-mate são de grande importância, porém, escassos. Diante disso, objetivou-se avaliar os efeitos da secagem na viabilidade e no desenvolvimento embrionário de sementes da espécie. A avaliação do efeito da secagem foi realizada mediante determinação do teor de água, teste de tetrazólio e desenvolvimento embrionário. Para avaliar a tolerância à dessecação, as sementes foram acondicionadas em uma bandeja plástica sem tampa, colocada em prateleira de câmara fria e seca (CFS), regulada com 25 ± 3% de umidade relativa do ar e temperatura de 10 ± 1°C, por 70 dias. A cada sete dias, as sementes foram retiradas da CFS e submetidas ao teste de tetrazólio e à avaliação do teor de água. O desenvolvimento embrionário foi avaliado a partir dos embriões excisados, oriundos do teste de tetrazólio. O teste de germinação foi conduzido no substrato areia, em caixas gerbox, acondicionadas em câmara de germinação regulada a 25°C e fotoperíodo de 12 horas. Das sementes que não foram submetidas à secagem, apenas 8% germinaram, resultado da imaturidade embrionária das sementes recém-colhidas. A secagem por 70 dias promoveu o desenvolvimento embrionário, mas afetou a viabilidade das sementes, sendo recomendada, portanto, sua secagem por até 49 dias para melhorar a germinação e posterior produção de mudas.

Abstract Yerba mate germination has been pointed as low, irregular and slow, with different degrees of dormancy, making the production of seedlings a great challenge. Studies to clarify the main mechanisms of dormancy present in yerba mate seeds are of great importance, but scarce. Therefore, we evaluated the effects of drying on the viability and the embryonic development of the species seeds. We evaluated the drying effect by determining the water content, tetrazolium test and embryo development. In order to evaluate the desiccation tolerance, the seeds were stored in a plastic tray without lid, placed on a cold and dry chamber (CFS) shelf, regulated with 25 ± 3% relative humidity and a temperature of 10 ± 1 ° C, for 70 days. Every seven days the seeds were removed from the CFS and submitted to tetrazolium test and water content evaluation. Embryo development was evaluated from excised embryos, originated from tetrazolium test. The germination test was conducted on sand substrate, in gerbox boxes placed in a growth chamber regulated at 25 °C and photoperiod of 12 hours. From seeds not subjected to drying, only 8% germinated, as a result of embryo immaturity of newly harvested seeds. Drying for 70 days promoted the embryonic development, but affected the viability of the seeds. Therefore, we recommend drying for up to 49 days to improve the germination and the subsequent seedling productions.