ABSTRACT The use of forest seedling banks is recommended for producing seedlings of species essential for specific forest typologies for which propagation poses challenges. However, given the lack of understanding of how human intervention, such as the removal of regenerating individuals from the forest, influences the composition and structure of the plant community, there is a pressing need for further research. Our primary objective here was to identify the effects of seedling removal on natural regeneration in forest communities and to characterize seedling bank dynamics three years after anthropogenic intervention. A randomized block design was used for the experiment, consisting of five removal intensities (0, 25, 50, 75, and 100% removal), with evaluations conducted every three months for three years. All individuals of the shrub-arboreal component between 5-55 cm heights were measured. Collected data were analyzed to determine the impacts of the removal of individuals and the influence of environmental elements on the seedling community. We found that the shrub-arboreal component of the forest community exhibited marked resilience three years following the removal of regenerating individuals. Removal of up to 50% of regenerating individuals does not appear to interfere with plant community dynamics, suggesting species with a high density of individuals in the seedling bank are resilient to the impacts of human intervention. Although climatic seasonality also affects seedling bank dynamics in plant communities, this effect depends on the level of human intervention in an area and, therefore, has been omitted from the analysis.

RESUMO O uso do banco de plântulas da floresta é indicado para produção de mudas de espécies importantes, porém de difícil propagação, para determinada tipologia florestal. No entanto, intervenções como a retirada de indivíduos regenerantes da floresta podem influenciara composição e a estrutura da comunidade de plantas, devendo ter seus impactos previamente estudados. Dessa forma, o presente estudo objetivou identificar os impactos da remoção de plântulas sob a regeneração natural de uma comunidade florestal, bem como caracterizar a dinâmica do banco de plântulas três anos após intervenção antrópica. O experimento foi conduzido no delineamento blocos ao acaso, sendo os tratamentos compostos por cinco intensidades de remoção de indivíduos do banco de plântulas (0, 25, 50, 75 e 100% de remoção) e realizadas avaliações a cada 3 meses, por um período de 3 anos. Foram mensurados todos os indivíduos do componente arbustivo-arbóreo com altura entre 5 e 55 cm. Os dados obtidos foram analisados quanto ao impacto causado pela remoção dos indivíduos e a influência dos elementos ambientais sobre a comunidade de plântulas. Após três anos de observações constatou-se que a vegetação do componente arbóreo-arbustivo apresentou capacidade de resiliência posterior a remoção dos indivíduos regenerantes. De maneira geral, a remoção de até 50% dos indivíduos não interfere na dinâmica da comunidade vegetal, podendo assim ser utilizada para espécies que apresentam elevada densidade de indivíduos no banco de plântulas. A sazonalidade climática direciona a dinâmica do banco de plântulas em comunidades vegetais, no entanto esta influência é dependente do nível de intervenção antrópica a qual a área foi submetida.

ABSTRACT Background: The increase in agricultural production requires sustainable alternatives development for reusing the waste generated, such as bovine manure, to obtain ecological, environmental, and economic benefits. In addition, proper fertilization is one of the main steps in the production of forest species seedlings. Thus, this study aimed to characterize the effect of different substrates formulations based on bovine manure and types of fertilizers on the quality of C. montevidense seedlings and verify if the field confirms the nurseries’ responses. The treatments consisted of three BM-based substrates combinations (S0 - control, no manure; S30 - 30% BM; and S60 - 60% BM) and four types of base fertilizers [Control: no fertilizer, FRF - Fast Release Fertilizer (NPK + fritted trace elements), FRF2 - twice as used in FRF and CRF - Controlled Release Fertilizer]. The substrates quality and the seedlings’ morphophysiological attributes were determined 160 days after sowing, then conducting the best treatments to the field. Results: We verified that the use of bovine manure improved the physical and chemical properties of the substrates. For the C. montevidense cultivation, 30% BM plus CRF provided the best seedling development. The substrate used in the seedlings production influenced the post-planting performance of C. montevidense, and the bovine manure use allows for more significant plant growth in the field. Conclusion: For the cultivation of Citharexylum montevidense, it is recommended to use substrates composed of 30% of bovine manure, associated with 6 g L-1 of controlled-release fertilizer, as it provides higher quality seedlings in shorter production time in the nursery.

ABSTRACT Background: Direct sowing technique is considered a promising tool for reducing costs and increasing species diversity in restoration projects. However, several factors can limit its success, making it necessary for methodological adjustments to be made in order to maximize the emergence, establishment and initial growth of plants. This study aimed to evaluate the influence of the use of fungus Trichoderma asperelloides and hydrogel in the enrichment direct sowing as a strategy to enrich the area in the initial restoration process. The forest species studied were Balfourodendron riedelianum, Cedrela fissilis, Luehea divaricata, Enterolobium contortisiliquum and Parapiptadenia rigida. The experiment was conducted in a factorial design testing absence or presence of the T. asperelloides and absence or presence of hydrogel. Two experiments were established: in the nursery, we evaluations of the emergence of the seedlings were carried out; in the field, we evaluated emergence, survival, height and stem diameter. Results: Under nursery conditions, inoculation and the use of hydrogel did not influence the emergence of species tested. Direct sowing proved to be a promising technique for the enrichment of young restoration plantations in subtropical regions with E. contortisiliquum, P. rigida and C. fissilis. B. riedelianum and L. divaricata seeds did not germinate in the field. Conclusion: The use of T. asperelloides is an efficient strategy to enhance the results of direct sowing, capable of providing higher rates of emergence for E. contortisiliqumm and P. rigida and maximizing the growth in height of E. contortisiliqumm. Under high pluviometric intensity, the use of the hydrogel does not influence the emergence and morphological attributes of the species studied. Background projects However success plants process fissilis T established out field survival diameter Results conditions tested E P C B L Conclusion intensity

ABSTRACT The use of auxin mimics herbicides in agriculture is widespread in a great diversity of crops. The indiscriminate use of herbicides can cause adverse effects in the plants. Among the plant species that stand out for being highly competitive and resistant to biotic and abiotic stresses, it is the brazilian peppertree (Schinus terebinthifolius Raddi.). The objective of this work was to evaluate the phytotoxic and photosynthetic alteration effects of different rates simulating the drift of the herbicides 2,4-D and Dicamba in brazilian peppertree seedlings. The experiment was carried out in a completely randomized design with four replications. The treatments were arranged in 2 x 8 factorial design (herbicide x doses). The factor herbicide consisted the herbicides 2,4-D and Dicamba, and, the factor doses eight percentages of the herbicide applied. Phytotoxicity and alteration of photosynthetic and fluorescence of chlorophyll a parameters were evaluated. Increased rate of the 2,4-D and Dicamba cause phytotoxicity to the plants, whose Dicamba promotes greater injuries. Dicamba was the herbicide that caused the greatest damage to the photosynthetic apparatus on brazilian peppertree plants, while for 2,4-D the plants showed higher recovery potential after herbicidal exposure.

RESUMEN: Los viveros forestales que producen seedlings de especies nativas deben poner a disposición una alta diversidad forestal para satisfacer las demandas de los proyectos de recuperación. De esta forma, comprender el comportamiento de las diferentes especies y mejorar la tecnología de producción califica el manejo y reduce las pérdidas. Por lo tanto, se estudió el efecto de la adición de polímero hidroretenedor al sustrato sobre el desempeño de tres especies nativas cultivadas en condiciones de vivero. El diseño experimental fue completamente al azar con un esquema factorial. Se investigaron rasgos de supervivencia, morfológicos y fisiológicos en plántulas. En general, se observó que las especies estudiadas resultaron aptas para la técnica de trasplante con alta supervivencia a pesar de la influencia negativa del hidrogel sobre esta variable en las plántulas. Por otro lado, el uso de polímero hidroretenedor mejoró el crecimiento en altura, diámetro del tallo y la calidad de estas plántulas, demostrando ser una estrategia viable en la producción de seedlings nativas en un vivero.

SUMMARY: Forest nurseries that produce native species seedlings need to make heigh forestry diversity available to supply the demands of forest ecosystem recovery projects. In this way, understanding the behavior of different species and improving production technology improve management and reduce losses. We here studied the effect of the water-retaining polymer addition to the substrate on the performance of three native species grown under nursery conditions. The experimental design was completely randomized with a factorial scheme. Survival, morphological and physiological attributes of seedlings were investigated. In general, it was observed that studied species proved to be suitable for the subculturing technique, with high survival despite of hydrogel negative influence on this variable in seedlings. On the other hand, the use of water-retaining polymer improved growth in height, stem diameter and seedlings quality, demonstrating to be a viable strategy in native seedlings production in a nursery.

RESUMEN: Eugenia uniflora es un árbol frutal de la familia Myrtaceae, nativo de Brasil, Argentina y Uruguay que tiene un alto potencial de uso en proyectos paisajísticos y ambientales, la industria alimentaria y farmacéutica. Sin embargo, todavía falta información sobre la producción de plantas de calidad. El objetivo de este trabajo fue identificar el sustrato adecuado y sus características, en relación al régimen hídrico para la producción de plántulas de E. uniflora. El experimento se realizó en un diseño de bloques al azar, en un esquema factorial, con cuatro tipos de sustratos probados (S1: 100 % turba - sustrato comercial (SC), S2: 80 % SC + 20 % cáscara de arroz carbonizada (CAC), S3: 60 % SC + 40 % CAC, y S4: 40 % SC + 60 % CAC) y cinco regímenes hídricos (RH) (4, 8, 12, 16 y 20 mm dia-1). Se evaluó la altura, el diámetro del cuello, la materia seca y el índice de calidad de Dickson. Los factores influyeron en los atributos medidos de forma aislada. Las plantas cultivadas en S1 presentaron el mayor crecimiento y acumulación de materia seca, siendo los resultados 72 % y 41 % superiores a S3. Eugenia uniflora mostró un crecimiento y una calidad de plántulas superiores en plantas de semillero más pequeñas. El uso de sustrato a base de turba, combinado con el uso de 4 a 8 mm RH dia-1, proporciona un rápido desarrollo de plántulas de E. uniflora en vivero.

SUMMARY: Eugenia uniflora is a fruit tree of the Myrtaceae family, native to Brazil, Argentina and Uruguay that has high potential for use in landscape and environmental projects, food and pharmaceutical industry. However, information on the production of quality seedlings is still scarce. The objective was to identify the appropriate substrate and its characteristics, in relation to the water regime for the production of E. uniflora seedlings. The experiment was conducted in a randomized block design, in a factorial scheme, with four types of substrates being tested (S1: 100 % peat - commercial substrate (CS), S2: 80 % CS + 20 % Carbonized Rice Husk (CRH), S3: 60 % CS + 40 % CRH and S4: 40 % CS + 60 % CRH) and five water regimes (WR) (4, 8, 12, 16 and 20 mm day-1). Height, stem diameter, dry matter and Dickson's quality index were evaluated. Factors influenced the measured attributes in isolation. Seedlings grown in S1 showed the highest growth and accumulation of dry matter. Results are 72 % and 41 % higher than those shown by S3. Eugenia uniflora showed superior growth and quality of seedlings under smaller WR. The use of peat-based substrate, combined with the use of 4 to 8 mm WR day-1, provides rapid development of E. uniflora seedlings in a nursery.

Abstract This study aimed to evaluate different container sizes and substrates formulated with agro-industrial residues to produce Handroanthus heptaphyllus and Schinus terebinthifolius seedlings. The experiment had a completely randomized design with four replications (48 seedlings each), in a factorial scheme (containers × substrates), with two containers (110 and 180 cm3) and ten substrates (agro-industrial residues (crushed peach pits and peel rice) mixed with organic compost). Carbonized and hydrolyzed rice husk (CRH and HRH, respectively) were used. At 90 and 108 days after the emergence of the S. terebinthifolius and H. heptaphyllus seedlings, the morphophysiological attributes were evaluated. Considering the attributes evaluated in this study, the 180 cm3 container promoted more significant seedling growth for both species. Substrates containing up to 20% CRH, HRH, or crushed peach pits (CPP) are indicated for S. terebinthifolius, and those with up to 30% CRH or 10% HRH or CPP are indicated for H. heptaphyllus.

Abstract Cabreúva (Myrocarpus frondosus Allemão) is a native species with ecological, ornamental, medicinal, and timber potential. This study aimed to evaluate the physical, physiological, and sanitary quality of Myrocarpus frondosus diaspores over 360 days in different storage environments. The initial characterization of the batch included the weight of 1,000 seeds, moisture content, electrical conductivity, germination potential (with substrates being between and on sand or vermiculite, and a paper roll) and sanitary quality (blotter test). The diaspores were stored in a room with ambient conditions, a dry and cold room, a wet and cold chamber, and a refrigerator. Evaluations were performed at 0, 90, 180, 270, and 360 days. The substrates between sand and between vermiculite are recommended for the germination of diaspores. Diaspores showed no recalcitrant behavior in relation to storage and can be stored in a dry and cold room (18 °C and 49% RH) for 360 days, with 57% germination. Fungal incidence increased the deterioration of the diaspores after 180 days of storage in a cold and dry environment.

ABSTRACT This study aims to report the occurrence of Heilipus draco in seeds of Ocotea puberula, and to describe the main injuries caused to the seeds and the effects on germination, as well as the occurrence of parasitoid hymenopterans. To this end, fruits of seven trees were selected, in the extreme south of the Atlantic Forest, Brazil. Fruit collection was carried out weekly in the middle third of the canopy, forming lots, from the beginning of fruit formation until total dehiscence, for two years. In order to examine the damage caused by the granivorous insects inside the fruits, 100 fruits were sectioned taking into account the batch/year with the aid of a scalpel and analyzed using a binocular stereomicroscope. In the same way, 144 fruits from each lot/year were stored individually in transparent plates in order to verify the occurrence and identification of species of granivorous insects. The proof of the influence of the injury caused to the seeds by the granivorous insects was carried out by the germination test, with four replications of 25 seeds, comparing seeds with and without oviposition holes. The species H. draco was found to be associated with the fruits of O. puberula. The egg-layings are endophytic, carried out directly on the seed. Larval parasitism of Hymenoptera Bracon, Omeganastatus, Scambus and Triapsis was observed. It is concluded that the cycle from egg to adult takes place inside the seed of O. puberula, and the injuries caused by the larvae decrease germination.

RESUMO Entre os métodos utilizados para a restauração de áreas alteradas, tem-se o plantio de mudas arbóreas nativas como um dos mais tradicionais. O objetivo desse estudo foi verificar a sobrevivência e o crescimento de mudas de Casearia sylvestris Sw, Handroanthus heptaphyllus Vell. Mattos e Parapiptadenia rigida Benth. Brenan, em área alterada, de acordo com o recipiente utilizado na produção das mudas em viveiro e do uso de mulching no plantio, por meio de atributos morfológicos e fisiológicos. O experimento foi conduzido em esquema fatorial 2x2, considerando tipos de recipientes na produção das mudas (saco plástico e tubete) e presença ou ausência de mulching no entorno das mudas no plantio. As três espécies apresentaram médias de sobrevivência semelhantes aos 24 meses. As taxas entre os tratamentos foram 72,5; 85,0 e 80,0%, respectivamente. Obteve-se efeito positivo do uso de saco plástico para incremento em altura (IncH) e em diâmetro coleto (IncDC), área da copa (AC) e massa seca da parte aérea (MSPA) para C. sylvestris e H. heptaphyllus, enquanto para P. rigida, o uso do saco plástico favoreceu à AC e MSPA. A presença de mulching favoreceu os atributos IncH, IncDC, AC e MSPA de H. heptaphyllus, bem como a AC e a MSPA de C. sylvestris. Quanto aos parâmetros fisiológicos (níveis relativos de clorofila a e b e fluorescência de clorofila a), não foi observada diferença entre os tratamentos testados. Indica-se que mudas de C. sylvestris, H. heptaphyllus e P. rigida, para plantio em área antropizada, sejam produzidas em recipiente saco plástico de 1,5 L visando maior crescimento a campo. Além disso, no plantio de C. sylvestris e H. heptaphyllus deve-se utilizar o mulching para favorecer seu crescimento.

ABSTRACT Among the methods used for the restoration of altered areas, the planting of native tree seedlings is one of the most traditional ones. The objective of this study was to evaluate the survival and initial growth of Casearia sylvestris Sw, Handroanthus heptaphyllus Vell. Mattos and Parapiptadenia rigida Benth. Brenan seedlings in altered areas, according to containers used in nursery seedlings production and use of mulching on planting, using morphological and physiological attributes. The experiment was conducted in a 2x2 factorial scheme. The type of containers used (plastic bag and tube) was considered, and the presence or absence of mulching around the seedlings. The three species presented similar survival averages at 24 months. The rates between the treatments were 72.5; 85.0 and 80.0%, respectively. The use of plastic bags had a positive impact on the height (IncH) and stem collar (IncDC), crown area (CA) and shoot dry mass (SDM) for C. sylvestris and H. heptaphyllus, while for P. rigida, the use of plastic bags favored the CA and the SDM. The presence of mulching favored the attributes IncH, IncDC, AC, and MSPA of H. heptaphyllus, as well as CA and SDM of C. sylvestris. Regarding the physiological parameters (relative levels of chlorophyll a and b and fluorescence of chlorophyll a), no difference was observed between the treatments tested. It is recommended that for the planting of seedlings of C. sylvestris, H. heptaphyllus, and P. rigida, in altered areas by anthropization, they be produced in a 1.5 L plastic bag, aiming at greater field growth. Also, in the planting of C. sylvestris and H. heptaphyllus the mulching should be used to favor their growth.

SUMMARY: The study aimed at characterizing the arboreal-shrubby component in fragments of Mixed Ombrophilous Forest, in Rio Grande do Sul State, Brazil. The vegetation survey was performed in four sampled fragments in 57 plots. In the plots, the identification of the individuals and measurement of circumference at breast height (CAP) was carried out, according to the following classes of size: Class I) arboreal strata, individuals with CAP ≥ 30 cm (10 x 20 m); Class II) arboreal strata, individuals with 15 ≤ CAP < 30 cm (10 x 10 m); Class III) established natural regeneration, individuals with 3 ≤ CAP < 15 cm (5 x 5 m) and Class IV) bank of seedlings, individuals with height ≥ 30 cm and CAP < 3 cm (2 x 2 m). The data of Class I constituted a matrix parcel x species, which was used in a multivariate analysis, allowing the classification of groups of plots that characterize microhabitats. The forest fragments presented low floristic richness of typical species of Mixed Ombrophilous Forest. From this environment highlight two main groups, one characteristic of riparian forest and the other from capões. In the riparian forests (GR1), highlighted Eugenia uruguayensis and Gymnanthes klotzschiana. In capões (GR2), the predominant species were Araucaria angustifolia, Podocarpus lambertii and Myrceugenia cucullata. The condition of species in different classes associated with their ecological characteristics allows identifying possible strategies for perpetuation of the arboreal-shrubby component of population and management of the fragments aiming at its conservation.

RESUMEN: El estudio tuvo como objetivo caracterizar el componente arbóreo-arbustivo en fragmentos de Bosque Umbrófilo Mixto. El relevamiento de la vegetación se realizó en cuatro fragmentos muestreados en 57 parcelas. Se identificaron los individuos y se midió la circunferencia a la altura del pecho (CAP), considerando las siguientes clases: Clase I) estrato arbóreo, CAP ≥ 30 cm (10 m x 20 m); Clase II) estrato arbóreo, 15 ≤ CAP < 30 cm (10 m x 10 m); Clase III) regeneración natural establecida, 3 ≤ CAP < 15 cm (5 m x 5 m) y clase IV) banco de plántulas, altura ≥ 30 cm y CAP < 3 cm (2 m x 2 m). Los datos del estrato arbóreo (Clase I) constituyeron una matriz de parcela x especie, la cual fue utilizada en análisis multivariado, permitiendo la clasificación de grupos de parcelas que caracterizan a los microhábitats. Los fragmentos de bosque en cumbres de la sierra presentaron baja riqueza florística de especies típicas del Bosque Umbrófilo Mixto. De este ambiente típico, se destacan dos grupos principales, uno característico de bosques de galería y el otro de bosques en islas (capões). En los bosques de galería (GR1), destacaron Eugenia uruguayensis y Gymnanthes klotzschiana. En los bosques en islas (GR2), las especies predominantes fueron Araucaria angustifolia, Podocarpus lambertii y Myrceugenia cucullata. La condición de especies en las diferentes clases asociadas a sus características ecológicas permite identificar posibles estrategias para perpetuar el componente arbóreo-arbustivo de las poblaciones y de fragmentos buscando su conservación.

ABSTRACT Plantations with native tree species, which emphasize biodiversity conservation, may not succeed because of a lack of forestry knowledge about the native species. Cabralea canjerana is an important tree species, which is rarely present in area restoration programs because of the difficulty in establishing it in plantations. Despite this, the species is also known for its adaptation to different light conditions. Therefore, this research sought to answer: a) What is the appropriate light level for the initial establishment of Cabralea canjerana seedlings in the field? b) Does seasonality influence the morphological and physiological attributes of Cabralea canjerana plants? The treatments used were: four shade intensities (0, 18, 50 and 70%) and two seasonal periods (spring-summer and autumn-winter). Survival was evaluated at 30 and 360 days after planting, while the morphological and physiological attributes were evaluated at 180 (spring-summer) and 360 (autumn-winter) days after planting. We suggest that Cabralea canjerana be classified as a moderately shade-tolerant species, considering that even in a region with four well-defined seasons, like the one in the present study, its mortality rate was high in full sun, a fact that is corroborated by the morphological and physiological parameters. The planting of Cabralea canjerana seedlings in full sunlight is not appropriate because it causes low seedling survival. It is recommended that planting be carried out under 50% shading. Seasonality influenced the morphological and physiological attributes of Cabralea canjerana plants.

SUMMARY: Light is an important environmental factor in the establishment of vegetation. The knowledge of the behavior of the species in response to light demand for survival and growth in the field becomes essential. Thus, the present study aimed at evaluating the survival and initial growth of Myrocarpus frondosus seedlings under different levels of shade in the field. The treatments used were: 0 % (full sun); 18 %; 50 % and 70 % shading in a randomized block design. The survival of seedlings was evaluated 30 and 540 days after planting (d.a.p.) and the morphological attributes height (H), stem diameter (DC) and H/DC ratio every 90 days. Leaf area, leaf dry matter, dry matter of stem and branches and dry matter of shoot were obtained 540 d.a.p. The analyses of the physiological attributes fluorescence of chlorophyll a and photosynthetic pigments were performed 180, 360 and 540 d.a.p. The use of shading in the planting of Myrocarpus frondosus influences the survival and the morphological and physiological attributes of the species. The morphological and physiological attributes of Myrocarpus frondosus plants show that the species requires shading of 50 to 70 % in its initial growth phase in the field (540 d.a.p.). It is recommended to use the species in sub-forest enrichment plantations and in consortium with other species more demanding in light.

RESUMEN: La luminosidad es un factor ambiental importante en el establecimiento de la vegetación, siendo imprescindible el conocimiento del comportamiento de las especies en respuesta a la demanda de luz para supervivencia y crecimiento en el campo. El presente estudio tuvo como objetivo evaluar la supervivencia y el crecimiento inicial de plantas de Myrocarpus frondosus bajo diferentes niveles de sombreamiento en el campo. Los tratamientos utilizados fueron 0 % (pleno sol), 18 %, 50 % y 70 % de sombreamiento en un diseño de bloques al azar. La supervivencia de las plantas fue evaluada a los 30 y 540 días después de la plantación (ddp) y los atributos morfológicos altura (H), diámetro del cuello (DAC) y relación H/DC cada 90 días. A los 540 ddp se obtuvo el área foliar, materia seca foliar, materia seca del tallo y ramas y la materia seca de la parte aérea. Los análisis de los atributos fisiológicos fluorescencia de la clorofila α y los pigmentos fotosintéticos fueron realizados a los 180, 360 y 540 ddp. La utilización de sombreamiento en la plantación de Myrocarpus frondosus evidencian que la especie necesita de 50 y 70 % de sombra en la fase inicial de crecimiento en el campo (540 ddp). Se recomienda el uso de la especie en plantaciones de enriquecimiento de sub bosque y en consorcio con otras especies más exigentes en luminosidad.

RESUMO A aplicação de doses de fósforo (P) no solo pode aumentar o crescimento de espécies arbóreas nativas de interesse econômico e ambiental, como a Cordia trichotoma. Assim, esta pesquisa tem por objetivo avaliar parâmetros morfológicos e fisiológicos em mudas de C. trichotoma cultivadas em solo com aumento do teor de P. O experimento foi conduzido em casa de vegetação, em vasos com 2,5 dm-3 de solo, com quatro doses de P (0, 150, 300 e 450 mg dm-3) e seis repetições. O teor de P no solo, as concentrações de P nas folhas, os atributos morfológicos (altura, diâmetro do coleto, matéria seca aérea, matéria seca radicular e área foliar) e os atributos fisiológicos (teor de pigmentos fotossintéticos e fluorescência da clorofila a) foram determinados aos 180 dias após o transplante. O incremento no teor de P disponível no solo permitiu maior absorção desse elemento pelas raízes das plantas, elevando a concentração nas folhas. Isso favoreceu o metabolismo energético das plantas, proporcionando maior crescimento. Além disso, o maior influxo e acúmulo de P na planta quando utilizado 450 mg dm-3, incrementou a concentração dos pigmentos fotossintéticos e elevou a capacidade fotossintética das mudas de C. trichotoma. O maior aproveitamento da energia luminosa pelo fotossistema II (Fv/Fm = 0,76) foi observado nas mudas cultivadas com 450 mg dm-3 de P, com aumento de 95% quando comparadas às mudas sem adição de P. Assim, percebemos que essa espécie arbórea, é exigente e responsiva em relação ao maior teor de P disponível no solo.

ABSTRACT The application of phosphorus (P) doses in the soil can increase the growth of native tree species of economic and environmental interest, such as Cordia trichotoma. Thus, this research aims to evaluate the morphological and the physiological parameters in C. trichotoma seedlings, cultivated in soil with increased P content. The experiment was conducted under greenhouse conditions in pots with 2.5 dm-3 of soil, four doses of P (0, 150, 300 and 450 mg dm-3), and six replicates. P content in the soil, P concentrations in the leaves, morphological attributes (height, stem diameter, aerial dry matter, root dry matter, and leaf area) and physiological attributes (photosynthetic pigment content and chlorophyll α fluorescence) were determined 180 days after transplantation. The increase in the available P content in the soil allowed greater absorption of this element by the plant’s roots, increasing the concentration in the leaves, and therefore favoring the energetic metabolism of the plants. In addition, the higher influx and accumulation of P in the plant when 450 mg dm-3 was used, increased the concentration of the photosynthetic pigments and increased the photosynthetic capacity of the C. trichotoma seedlings. The highest use of the light energy by photosystem II (Fv/Fm = 0.76) was observed in the seedlings cultivated with 450 mg dm-3 of P, with a 95% increase when compared to seedlings without P. Thus, we observed that this tree species is demanding and responsive to the higher P content available in the soil.

Abstract In forest nurseries, one of the factors that change the growth and quality of seedlings is water supply, which has a direct influence on metabolic processes such as stomatal conductance and photochemical efficiency of photosystem II. This study aims to identify the influence of different watering regimes as well as the use of a water-retaining polymer on the initial growth and metabolic processes of Enterolobium contortisiliquum seedlings. The experimental design was in random blocks with a factorial scheme. Morphological attributes, as well as physiological and biochemical attributes were investigated. We verified that the performance of E. contortisiliquum seedlings depends on the watering regime provided to the plants; furthermore, up to 60 days after the application of the treatments, both the height and diameter of the collection and the leaf water potential were similar in the water regimes of 8 mm day-1 and 12 mm day-1.