Resumo A produção de mudas de nogueira-pecan tem ganhado força nas últimas décadas, principalmente na região sul do Brasil, e esse aumento na demanda, consequentemente, intensifica os estudos sobre problemas fitossanitários presentes na cultura nessa região. A qualidade sanitária é um fator importante na produção de mudas florestais, tendo em vista a ocorrência de doenças em todas as etapas do processo produtivo. Em abril de 2021, foram observadas manchas foliares escuras e irregulares em mudas de nogueira-pecan em condições de viveiro. A evolução dos sintomas causava queda dos folíolos e comprometimento no desenvolvimento das plantas, devido à redução da sua área fotossintética. Verificou-se que se tratava do efeito causal de um fungo, que foi isolado em meio batata-dextrose-ágar (BDA), tendo, posteriormente, sua patogenicidade constatada em folíolos destacados de nogueira-pecan. Discos de 4 mm da cultura pura do isolado de Phomopsis sp. foram dispostos na superfície de folíolos sadios, previamente feridos com agulha histológica esterilizada. Após a inoculação, os folíolos foram acondicionados em caixas gerbox forradas com duas folhas de papel-filtro esterilizadas e umedecidas com água destilada esterilizada e mantidas em câmara de incubação durante sete dias a 25 ± 2ºC e fotoperíodo de 12 h. Foram utilizados oito folíolos sadios como testemunha, os quais foram submetidos às mesmas condições, utilizando apenas discos de meio de cultura BDA. O isolado mostrou-se patogênico, com os primeiros sintomas após 6 dias da inoculação. As lesões, inicialmente circulares e necróticas, foram coalescendo e aos 10 dias atingiram 16 mm. Foi realizado o reisolamento assim que as estruturas reprodutivas do fungo apareceram, essas foram transferidas para placas de Petri com meio de cultura BDA. O fungo causador dos sintomas foi identificado como Phomopsis sp., e este trabalho apresenta o primeiro relato da ocorrência de mancha foliar de Phomopsis sp. em Carya illinoinensis em condições de viveiro no Brasil.

Abstract Pecan seedlings production has increased in recent decades, especially in southern Brazil, consequently, intensifies studies in crop phytosanitary problems in this region. Sanitary quality is an important factor in the production of forest seedlings, considering the occurrence of diseases in all stages of the production process. In April 2021, dark and irregular leaf spots were observed in pecan seedlings under nursery conditions. The evolution of symptoms caused leaf drop and compromised plant development, due to the reduction of their photosynthetic area. It was verified that it was a fungus, which was isolated on potato-dextrose-agar (PDA) medium, and later had its pathogenicity verified in detached pecan leaflets. Four-mm disks of the pure culture of the Phomopsis sp. were placed on the surface of healthy leaflets, previously injuredwith a sterilized histological needle. After inoculation, the leaflets were placed in gerbox boxes lined with two sheets of sterilized filter paper and moistened with sterilized distilled water and kept in an incubation chamber for seven days at 25 ± 2ºC and 12 h photoperiod. Eight healthy leaflets were used as controls, which were subjected to the same conditions, except for fungus inoculation, using only disks of PDA culture medium. The isolate proved to be pathogenic, with the first symptoms after 6 days of inoculation, the initially circular and necrotic lesions coalesced and at 10 days reached 16 mm. The re-isolation was carried out as soon as the reproductive structures of the fungus appeared, these were transferred to Petri dishes with PDA culture medium. The fungus causing the symptoms was identified as Phomopsis sp. and, this work presents the first report of the occurrence of Phomopsis sp. in Carya illinoinensis under nursery conditions in Brazil.

RESUMO Mudas de erva-mate com qualidade genética e fisiológica, altos índices de sobrevivência no plantio e resistência a estresses ambientais são necessários para a implantação e estabelecimento de ervais produtivos que irão fornecer matéria-prima de qualidade. No entanto, a produção de mudas, na maioria dos casos, é realizada a partir de sementes, as quais são coletadas de plantas matrizes com poucos critérios de seleção. Nesse sentido, o trabalho teve como objetivo investigar a qualidade das sementes de erva-mate após pré-limpeza por flutuação de diferentes plantas matrizes, por meio da obtenção de informações sobre a caracterização biométrica (medida longitudinal e transversal), teor de água, peso de mil sementes, avaliação da integridade das sementes e viabilidade por meio do teste de tetrazólio. As sementes foram coletadas de 10 plantas matrizes localizadas em três municípios da região ervateira Alto Vale do Taquari - RS, Brasil. Na avaliação da integridade foram contabilizadas a quantidade de sementes não íntegras (vazias e deterioradas) e íntegras (com e sem embrião visível). E no teste de tetrazólio foi avaliada a porcentagem de sementes viáveis e não viáveis. As sementes das diferentes plantas matrizes apresentaram diferenças estatísticas para todas as variáveis analisadas. As análises mostraram que há diferenças relacionadas à biometria e teor de água e, consequentemente, no peso de mil sementes. A erva-mate apresenta percentual variado de sementes vazias e deterioradas. A porcentagem de sementes não viáveis é alta, o que reduz significativamente a viabilidade de um lote de sementes.

ABSTRACT Yerba mate seedlings with genetic and physiological quality, high rates of sowing survival and resistance to environmental stresses are necessary for the implantation and establishment of productive plants that will provide quality raw material. However, the production of seedlings, in most cases is carried out from seeds, which are collected from mother-plants with few selection criteria. In this sense, the work aimed to investigate the quality of the seeds of yerba mate after processing by flotation from different mother-plants, by obtaining information about the biometric characterization (longitudinal and transversal measure), water content, a thousand-seed weight, evaluation of the seed integrity and viability through the tetrazolium test. The seeds were collected from 10 mother-plants located in three cities in the yerba-mate region Alto Vale do Taquari - RS state, Brazil. In the integrity assessment, the number of not full (empty and deteriorated) and full (with and without visible embryo) seeds was counted. In the tetrazolium test, the percentage of viable and non-viable seeds was evaluated. The seeds of the different parent plants showed statistical differences for all the variables analyzed. The analysis showed that there are differences related to biometric parameters and water content and, consequently, in the weight of a thousand seeds. Yerba mate shows a varied percentage of empty and deteriorated seeds. The percentage of non-viable seeds is high, which significantly reduces the viability of the seed lot.

ABSTRACT: The characterization of substrate properties supports the correct choice of components and directs management decisions in container cultivation. There are several systems of analysis, however, the routine procedures to determine the water retention curve (WRC) are time consuming and inaccurate. This study proposed a reproducible, less time-consuming, and easy to perform method for physical characterization of substrates. We used Sphagnum peat, coconut powder, carbonized rice husk, expanded vermiculite, and expanded clay in isolation. The WRC was obtained at tensions 0, 10, 50, and 100 hPa using the method of Büchner funnel, the European standard (CEN-EN13041), and by the centrifugation method of samples. In centrifugation, tensions were simulated by combining the angular velocity, sample height, and radius measured from the sample outermost point to the central point of the centrifuge. Three rotations were applied (230; 520 and 730 rpm), testing the centrifugation time for each tension and then the volumetric water content was compared between the methods. The results showed a positive correlation (p < 0.001) between the centrifugation and standard methods, considering that the centrifugation time required for moisture stabilization varied according to the material analyzed and the tension applied. However, the time required to obtain a report was reduced by half. Sample centrifugation is a promising method, ensuring that the tensile force actually acts on the entire sample to determine the water retention curve of the substrate also reducing the duration of the analyses.

Abstract This study evaluated the effect of disinfestation methods and different storage environments on the germination of seeds of Limonium brasiliense (Boiss.) Kuntze. Seeds were disinfested using ethanol followed by sodium hypochlorite; water under agitation; and no disinfestation from two origins. Longevity was tested by storing the seeds in a cold chamber, dry chamber, and at ambient laboratory temperature. Beginning of germination (BG), percentage (%G), and mean germination time (MGT) and mean germination speed index (MGSI) were evaluated. Data were submitted to an analysis of variance, comparison of mean values and a polynomial regression analysis (p<0.05). In the disinfestation, there was significant difference in %G and MGT only between origins. For longevity, IG and MGSI had a positive and negative linear behavior, respectively, while %G had a quadratic behavior. L. brasiliense seeds disinfestation does not affect germination. Dry chamber was the most suitable storage environment.

ABSTRACT Agroforestry systems (AFS) represent an alternative to the current agricultural model, based on monoculture, mechanization, and intensive use of agrochemicals. The aim of this study was to characterize existing AFS in the Southern region of Brazil and understand how their forestry certification process is conducted by the official governmental body (SEMA-RS). Interviews were carried out with the owners of five AFS and one technical visit was made to SEMA-RS. Changes in production model resulted from a process of raising farmers’ awareness, which was observed when the main reason mentioned by farmers for implementing AFS is to ensure a healthier life quality. Another reason mentioned is that this system is economically and environmentally feasible and complies with current legislation. On the other hand, SEMA-RS facilitated the certification process by developing a simplified and quicker modality for AFS. The support of technicians and associations helps by providing access to information and to a successful production. This study confirms the effectiveness of AFS and the need to further their visibility so that they are implemented in other locations, especially in degraded areas, thus contributing with environmental preservation and with improving the health of the population, from farmers to consumers.

Resumo Considerando-se que os substratos apresentam constituições físico-químicas diversas e que a liberação de íons do substrato, ou a adição de fertilizantes, eleva a condutividade elétrica da solução, este trabalho teve como objetivo avaliar a retenção de água em substratos com hidrogel com presença e ausência de adubação. O delineamento experimental utilizado foi o inteiramente casualizado, em esquema fatorial 4 x 3 x 2, com quatro repetições. Os fatores constituíram de quatro tipos de substratos (casca de pinus compostada, pó-de-coco (fibra do mesocarpo triturada), turfa de Sphagnum e substrato comercial (à base de turfa de Sphagnum, vermiculita expandida, casca de arroz torrefada, calcário dolomítico e gesso agrícola), três formas de aplicação do produto hidrogel (sem aplicação, com aplicação sem pré-hidratação e com aplicação após hidratação) e duas formas de aplicação de fertilização de base (na presença e ausência). O hidrogel utilizado foi um copolímero de poliacrilato de potássio (K2S2O8). Os resultados apontam que a adição de hidrogel promove melhorias na capacidade de retenção de água dos substratos, contudo, é influenciada pela sua composição e pela presença de fertilizantes químicos. Quanto maior a Condutividade Elétrica (CE) do substrato, menor é o potencial de hidratação do hidrogel. A forma de aplicação do hidrogel, se seco ou pré-hidratado, não influencia a capacidade de retenção de água pelos substratos. O hidrogel aplicado no substrato, uma vez desidratado, mantém sua capacidade de reidratação.

Abstract Considering that the substrates have different physical and chemical constitutions and that the release of ions from the substrate or the addition of fertilizers increases the electrical conductivity of the solution, the objective of this work was to evaluate the water retention in substrates with hydrogel, without and with fertilization. The experimental design used was a completely randomized, in a 4 x 3 x 2 factorial scheme, with four replications. The factors consisted of four substrates (composted pine bark, coconut powder (crushed mesocarp fiber), Sphagnum peat and commercial substrate (based on Sphagnum peat, expanded vermiculite, roasted rice husk, dolomitic limestone and plaster), three forms of application of the hydrogel product (without application, with application without pre-hydration and with application after hydration) and two ways of applying the basic fertilization (present and absent) .The hydrogel used was a potassium polyacrylate copolymer (K2S2O8). The results show that the addition of hydrogel promotes improvements in the water retention capacity of the substrates However, it is influenced by its composition and by the presence of chemical fertilizers. The higher the EC of the substrate, the lower the hydration potential of the hydrogel. The hydrogel application method, whether dry or pre-hydrated, does not influence the water retention capacity by the substrates. The hydrogel applied to the substrate once dehydrated, maintains its ability to rehydrate.

SUMMARY: Butia odorata is an endangered palm tree native of southern Brazil and Uruguay with great food and ornamental potential. The lack of phytotechnical information hinders the commercial production of their seedlings. The aim of this work was to test doses of fertilization on the formation of B. odorata seedlings and tolerance to salinity levels in the substrate. The seedlings were cultivated in containers, submitted to control and four doses of fertilizer per liter of substrate. We evaluated stem diameter, number of leaves and pinnate leaves, electrical conductivity (EC) and pH of the substrate. The experimental design was in random blocks with 10 plants per treatment. Dry density, air space, and total pore space of the substrate were within the ideal ranges, such as EC and pH, without a significant trend for these last two variables in relation to the doses of fertilizers. Throughout the experiment, the pH remained adequate, except for higher dosage treatments that acidified the substrate. EC increased gradually, except for control treatment. There was a significant difference between treatments and blocks for plant variables, with the second access plants presenting larger stem diameter. The dosages that induced higher responses were 0.6 and 1.2 g L-1 with EC corresponding to 5 mS cm-1, which is possibly the limit of salts in the substrate tolerated by the species. B. odorata responded positively to the fertilization during the formation of the seedlings. However, until the juvenile phase, its development is impaired if EC reaches 5 mS cm-1.

RESUMEN: Butia odorata es una palmera en peligro de extinción originaria del sur de Brasil y Uruguay con gran potencial alimenticio y ornamental. La falta de información fitotécnica dificulta la producción comercial de sus plantas. El objetivo de este trabajo fue evaluar fertilización en la formación de plantas de B. odorata y su tolerancia a la salinidad del sustrato. Las plantas se cultivaron en contenedores, sometidas a control y cinco dosis de fertilizante. Fueron evaluados: diámetro del tallo, número de hojas y hojas pinnadas, conductividad eléctrica (EC) y pH del sustrato. El diseño experimental fue en bloques aleatorizado con 10 plantas por tratamiento. La densidad aparente, el espacio de aire y el volumen total de poros del substrato estuvieron dentro de rangos ideales; también la EC y el pH, sin tendencia significativa para estas dos últimas variables en relación con las dosis de fertilizantes. El pH se mantuvo adecuado, excepto con dosis más altas que acidificaron el sustrato. La EC aumentó gradualmente, excepto para el tratamiento de control. Hubo diferencia significativa entre tratamientos y bloques para las variables de la planta. Las dosis que indujeron respuestas mayores fueron 0,6 y 1,2 g L-1 con EC de 5 mS cm-1, que es posiblemente el límite de sales en el sustrato tolerado por la especie. Butia odorata respondió positivamente a la fertilización durante la formación de las plantas. Sin embargo, hasta la fase juvenil, su desarrollo se vio afectado cuando la EC alcanzó 5 mS cm-1.

SUMMARY: Butia lallemantii is endemic from sandy soils in the state of Rio Grande do Sul (RS). Sandblasted soils stand out for fragile characteristics of low fertility, water availability and intense sand displacement. However, studies on planting techniques, use of fertilizers and alternative products that may favor the establishment of plants in these soils are lacking. Therefore, the objective of the study was to evaluate the survival and leaf appearance of the B. lallemantii plants established by the revegetation method in sandy soil, with the increase of mineral fertilizer and hydroretentor polymer, as well as monitoring the movement of sand particles. The plants were collected in Alegrete / RS, classified in stipe diameter and kept in substrate (soil, animal waste and rice husk, 1:1:1) for eight months. In field plantation, the doses of NPK and hydrogel were randomly placed between five graded rules in the soil, for periodic sand displacement readings. Survival, appearance of live leaves and sand displacement were evaluated monthly, with a randomized block design (100 seedlings/block). Results showed higher survival and presence of living leaves in the plants of block one, and average displacement of sand in the spring period. Therefore, plants of larger stipe diameter class show higher potential for survival and larger number of live leaves, in addition, sand displacement mainly happens during spring.

RESUMEN: Butia lallemantii es endémica proveniente de suelos arenosos y arenizados en el estado de Rio Grande do Sul (RS). Los suelos arenizados se destacan por características frágiles de baja fertilidad, disponibilidad de agua y por intenso desplazamiento de arena. Sin embargo, faltan estudios acerca de técnicas de plantación, uso de fertilizantes y productos alternativos que pueden favorecer el establecimiento de plantas en estos suelos. Por lo tanto, el objetivo del estudio fue evaluar la supervivencia y el aspecto foliar de las plantas de B. lallemantii establecidas por el método de revegetación en el suelo arenizado, con el incremento de fertilizante mineral y polímero hidroretentor, así como monitorear el desplazamiento de partículas de arena. Las plantas fueron recolectadas en Alegrete/RS, clasificadas de diámetro del estípite y se mantuvieron en sustrato (suelo, residuos animales y cáscara de arroz, 1:1:1), durante ocho meses. En plantación de campo, las dosis de NPK e hidrogel fueron colocadas aleatoriamente entre cinco reglas graduadas en el suelo, para lecturas periódicas de desplazamiento de arena. La supervivencia, la apariencia de hojas vivas y el desplazamiento de la arena se evaluaron mensualmente, con diseño en bloques al azar (100 plántulas/bloque). Los resultados mostraron una mayor supervivencia y presencia de hojas vivas en las plantas de bloque uno, y un desplazamiento promedio de arena en el período de primavera. Por lo tanto, las plantas de mayor clase de diámetro del estípite pose en alto potencial de supervivencia y de hojas vivas, además, la temporada de primavera mayor desplazamiento de arena.

Resumo Campomanesia aurea é uma espécie sub-arbustiva nativa do Bioma Pampa, conhecida popularmente com guabirobinha-do-campo. Apresenta potencial ornamental para uso em vasos ou jardins devido ao seu pequeno tamanho, forma irregular, floração intensa e aromática. Um dos principais fatores para a produção é o uso adequado de fertilizantes e adubações equilibradas. O objetivo foi avaliar o crescimento de mudas e o conteúdo de nutrientes nas folhas de C. aurea submentidas a doses de fertilizante de liberação controlada (FLC). Mudas de C. aurea foram transplantadas para embalagens contendo casca de pinus compostada e as dose de FLC de: 0; 2,5; 5,0; 7,5 e 10,0 g L−1. Avaliou-se a altura, índice de clorofila, número de ramificações, diâmetro de colo, área foliar, Índice de Qualidade de Dickson, massa seca da parte aérea, massa seca de raiz e acúmulo de nutrientes nas folhas. Para altura, diâmetro de coleto, número de hastes, o ponto de máxima resposta foi com a concentração de 6,8; 6,6; e 6,9 g L−1 de FLC, respectivamente. Para a massa seca da parte aérea, área foliar e índice de clorofila verificaram-se aumentos até a concentração 8,1; 7,8 e 8,0 g L−1, respectivamente. Houve comportamento quadrático positivo para a maioria dos nutrientes, com exceção de Cu e Mn, que foi linear crescente com o aumento da dose de fertilizante. A aplicação de FLC em mudas de C. aurea entre 7 e 8 g de substrato L−1 promoveu um aumento nas principais características de crescimento de importância ornamental e proporciona resultados superiores no acúmulo de nutrientes nas folhas.

Abstract Campomanesia aurea is a sub-shrub species native to the Pampa Biome, popularly known as “guabirobinha-do-campo”. It has an ornamental potential for use in pots or gardens due to its small size, irregular shape, intense flowering and aroma. One of the main factors for production is an adequate use of fertilizers and balanced fertilizations. The objective was to evaluate the growth of seedlings and nutrient leaf accumulation of C. aurea submitted to doses of controlled release fertilizer (CRF). C. aurea seedlings were transplanted to containers containing composted pinus bark and CRF doses of 0, 2.5, 5.0, 7.5 and 10.0 g L−1. Height, chlorophyll index, number of stems, base diameter, leaf area, Dickson Quality Index, shoot dry matter, root dry matter and nutrient leaf accumulation were evaluated. For height, base diameter and number of stems, the point of maximum response was at the concentration 6.8, 6.6 and 6.9 g L−1 CRF, respectively. For shoot dry matter, leaf area and chlorophyll, we verified increase up to the concentration 8.1, 7.8 and 8.0 g L−1, respectively. There was a positive quadratic behavior for most nutrients, with the exception of Cu and Mn, which linearly increased with the increase of fertilizer dose. The application of CRF on C. aurea seedlings between 7 and 8 g L−1 substrate promoted an increase on the main growth characteristics of ornamental importance and provides superior results on nutrient leaf content.

Resumo Possuidores de elevada biodiversidade, os campos do sul do Brasil vêm sendo ameaçados por diversos fatores, dentre eles, o avanço das fronteiras agrícolas. Áreas de Preservação Permanente (APPs) podem contribuir para a conservação da biota desses ecossistemas mesmo em paisagens cultivadas. O objetivo deste estudo foi descrever a diversidade florística de quatro APPs inseridas em um plantio comercial de Eucalyptus saligna. localizado em Pantano Grande, Rio Grande do Sul, no bioma Pampa. Durante um ano, excursões mensais foram realizadas utilizando o método do Caminhamento para coleta de material botânico. Foram registradas 295 espécies distribuídas em 60 famílias, as mais representativas foram Poaceae (51 spp.), Asteraceae (51 spp.), Cyperaceae (20 spp.), Fabaceae (17 spp.), Rubiaceae (12 spp.), Solanaceae (8 spp.), Malvaceae (8 spp.) e Myrtaceae (6 spp.), correspondendo 56,27% do total. Sobre a origem, 274 espécies são nativas, quatro das quais endêmicas do Brasil e duas ameaçadas de extinção. Em relação ao hábito, as espécies herbáceas foram predominantes (72,2%), seguido por arbustivas (9,58%), subarbustivas (7,87%), arbóreas (6,16%), e trepadeiras (5,13%). Tanto a proporção das famílias, quanto a relação das espécies identificadas corroboram com levantamentos realizados na região, denotando uma elevada riqueza específica. As APPs avaliadas apresentam elevada diversidade florística, mesmo encontrando-se parcialmente isoladas pelos talhões de plantio comercial de eucalipto.

Abstract Grasslands of southern Brazil are composed of high biodiversity and threatened by several factors, such as the advancement of agricultural frontiers. Areas of Permanent Preservation (APP) can contribute to the preservation of these environments. However, studies on their floristic composition are limited, especially about the herbaceous stratum. The objective of this study is to describe the floristic diversity of four Areas of Permanent Preservation inserted in an Eucalyptus saligna. tree crop farm in Pantano Grande, RS, located in the Pampa biome. For a year, monthly collections were performed by walking along all sampled areas. We identified 295 species distributed in 60 families, which Poaceae (51), Asteraceae (51), Cyperaceae (20), Fabaceae (17), Rubiaceae (12), Solanaceae (8), Malvaceae (8) and Myrtaceae (6) were more expressive, corresponding to 56.27% of total. About the origin, 274 species are native, four are endemic and two are endangered. Herbaceous species were predominant (72,2%), followed by shrubs (9,58%), sub-shrubs (7,87%), trees (6,16%) and vines (5,13%). Both the proportion of the families and the relation of species agree with surveys carried out in the region, denoting a high specific richness. The APP evaluated present high floristic diversity, even though they are partially isolated by the eucalyptus forest.

Abstract The propagation of guabijuzeiro (M. pungens) by seed is originating plants with high genetic variability and a long juvenile period. Therefore, the objective was to study the multiplication and rooting in vitro of guabijuzeiro in order to get information to enable the clonal propagation. In the multiplication, apical and nodal segments were used, taken from in vitro plantlets, combined with 6-Benzylaminopurine (BAP), naphthaleneacetic acid (NAA) and gibberellic acid (GA). In the rooting, NAA and IBA (indolebutyric acid) were used. The results showed that in the multiplication there was superiority in media with BAP, while rooting was not satisfactory in media with NAA or IBA. Thus, it is possible to multiply M. pungens in vitro using BAP phytoregulator in the multiplication stage. However, the rooting stage needs more tests to induce the production of roots and facilitate acclimatization of the plants obtained in vitro.

Abstract Butia odorata is a palm native to southern Brazil and Uruguay, not domesticated, much appreciated for its fruits and economic potential. However, the extractivism and the difficulty of propagation have led to the decline of natural populations. The objective of this work was to prove the possibility of induction of somatic embryogenesis in B. odorata. Mature zygotic embryos were induced in two media, MS and Y3, combined with auxin 2,4-D and picloram in five concentrations (2,4-D: 0, 361.99, 452.49, 542.99 and 633.48 μM/L, picloram: 0, 50, 150, 300 and 450 μM/L). The results promising during induction with the formation of embryogenic calli and somatic embryos, however the regeneration of them was not efficient, this may be due to the occurrence of somatic embryos fused during its development. The roots were formed, but the aerial part remained molten, not completing its development. Auxin picloram and Y3 medium provided the most adequate conditions for calogenesis, formation of embryogenic callus and somatic embryos, with concentrations of 150, 300 and 450 μM/L. This is the first description of somatic embryogenesis in B. odorata that will serve as the basis for future research and adjustments of the methodology proposed here.

RESUMO A capacidade de hidratação do hidrogel em solução foi avaliada em diferentes níveis de condutividade elétrica (CE), usando nitratos, fosfatos, sulfatos e sais de cálcio, magnésio e potássio. Foram realizados quatro experimentos sequenciais, utilizando-se um copolímero de poliacrilato de potássio. O primeiro ensaio objetivou determinar a menor dose de hidrogel, na qual se obtivesse a máxima absorção de água deionizada e foi montado num delineamento inteiramente casualizado, com seis doses de hidrogel (1, 2, 4, 6, 8 e 10 g L-1) e quatro repetições. O segundo estudo, montado num delineamento experimental inteiramente casualizado, com quatro repetições, consistiu em testar doses de sacarose P.A. (0, 1, 2, 4 e 6 %), afim de avaliar a alteração no potencial osmótico da solução sobre a hidratação do hidrogel. O terceiro e o quarto estudos foram desenvolvidos em delineamento inteiramente casualizado, num esquema fatorial 6 × 3 × 2, com quatro repetições. Para o terceiro estudo, os fatores constituíram de seis níveis de CE (0; 0,25; 0,50; 1,00; 1,50 e 2,00 mS cm-1), elevada pela adição de três ânions (NO3-; PO43- e SO42-), acompanhados pelos contra-íons Ca++ e K+. Para o quarto estudo, os mesmos seis níveis de CE foram atingidos pela adição de três cátions (Ca++, Mg++ e K+), acompanhados pelos contra-íons Cl- e SO42-. A capacidade de hidratação do hidrogel reduz com a elevação da concentração iônica da solução e que a redução do potencial osmótico, pela adição de sacarose, não interfere na sua capacidade de intumescimento. Os ânions e cátions em solução influenciam negativamente no processo de hidratação do hidrogel, sendo o efeito mais pronunciado para aqueles de maior valência..

ABSTRACT Hydrogel hydration capacity in solution was evaluated at different levels of electrical conductivity (EC) using nitrate, phosphates, sulfates, and salts of calcium, potassium and magnesium. Four sequential experiments were performed using potassium polyacrylate copolymer. The first experiment aimed to determine the lowest hydrogel dose, at which occur maximum deionized water absorption. The test was assembled in a completely randomized design with six hydrogel doses (1, 2, 4, 6, 8 and 10 g L-1) and four replicates. The second experiment consisted of testing the sucrose P.A. doses (0, 1, 2, 4 and 6 %) in order to evaluate the change in osmotic potential of the solution on hydrogel hydration. The third and fourth studies were carried out in a complete randomized design, using a 6 x 3 x 2 factorial scheme with four replicates. For the third experiment, the factors were six levels of EC (0; 0.25; 0.50; 1.00; 1.50 and 2.00 mS cm1) increased by the addition of three anions (NO3-; PO43- and SO42-) along with counter-ions Ca++ and K+. For the fourth experiment, the same six levels of EC were achieved by adding the three cations (Ca++, Mg++ and K+), along with the counter-ions Cl- and SO42-. Hydration capacity of the hydrogel decreases when the ionic concentration of the solution increases and the reduction of the osmotic potential through the addition of sucrose does not interfere in its swelling capability. Anions and cations in the solution negatively influence the process of the hydrogel hydration. The most pronounced effect is for those with higher valence.

Lupinus albescens é uma espécie frequente nos locais de arenização no Rio Grande do Sul, com alta rusticidade e rápida cobertura vegetal, mostrando potencialidades para recomposição de áreas degradadas. O objetivo foi avaliar a emergência e o desenvolvimento de L. albescens, com e sem aplicação de adubação mineral consorciada com a palmeira Butia lallemantii Deble & Marchiori. Sementes foram coletadas em três populações e submetidas à escarificação por 40 segundos. A sementeira foi feita entre nove fileiras (2 x 1 m) de B. lallemantii aplicando-se 0 e 30 g/cova do fertilizante mineral NPK (5-20-20). Avaliações: número de plantas por cova (NPC), altura (cm) e diâmetro do caule (mm), nos períodos de 30 e 60 dias, assim como a percentagem de emergência de plantas/m² (PEP) e o total emergência de plantas (TEP) ao longo de 240 dias, utilizando delineamento em blocos casualizados. Os resultados mostraram considerável PEP e altura aos 30 dias para as plantas do bloco 2. Dose de 0g/cova do fertilizante NPK proporcionou maior NPH. Portanto, a sementeira de L. albescens consorciada com B. lallemantii apresentou maior PEP, NPC sem o uso de adubação (30 dias) e maior altura das plantas entre as plântulas de diâmetro do estipe médio.

Lupinus albescens is a species frequent in the locals under arenization in Rio Grande do Sul, with high rusticity and rapid land cover, showing potentialities for recomposition of degraded areas. The objective was to evaluate the emergence and development of L. albescens, with and without mineral fertilizer application intercropped with the palm Butia lallemantii Deble & Marchiori. Seeds were collected in three populations and submitted to the scarification for 40 seconds. Sowing was done between nine rows (2 x 1 m) of B. lallemantii by applying 0 and 30 g/hole of the mineral fertilizer NPK (5-20-20). Evaluations: number of plants per hole (NPH), height (cm) and stem diameter (mm), in the periods of 30 and 60 days, as well as the percentage of plants emergence/m² (PEP) and the total of plants emergence (TEP) over 240 days, using randomized block design. The results showed a considerable PEP and height at 30 days for the plants in block 2. Dose of 0g/hole of fertilizer NPK provided higher NPH. Therefore, sowing of L. albescens intercropped with B. lallemantii presented higher PEP, NPH without the use of fertilization (30 days) and higher height of the plants among the diameter seedlings of the medium stipe.

Abstract Seasonality and lack of organic substrates suitable for the production of citrus rootstocks are the main problems in seedling production, coupled with the fact that these materials have alkaline pH. The objective of this study was to evaluate the effect of substrates composed of Pinus sp. needles and a commercial alkaline substrate at different concentrations on the growth and development of Poncirus trifoliata (L.) Raf rootstock. The development of 'Trifoliata' was assessed in different mixtures (v:v) of a commercial substrate (Vida®) based on eucalyptus bark and Pinus sp. needles (0, 25, 50, 75 and 100 %) with two particle sizes (3.5 and 8.0 mm). A randomized block experimental design with 10 treatments of seven plants each and four replications was used. During rootstock development, we monitored: the pH, electrical conductivity and stability of the substrates; the dry mass of the aerial part, roots and stem; and vegetative growth and development. Increasing the proportion of needles in the mixture with alkaline substrate reduced the pH, electrical conductivity and density. Treatments with 3.5 mm needles showed greater stability than those with 8 mm ones. The use of 25 % needles provided better results compared to 0 % (alkaline substrate only); however, the need for a specific fertilization and irrigation system for each treatment was detected, as each new substrate has its own physical and chemical characteristics.

Resumen La estacionalidad y carencia de sustratos orgánicos adecuados para la producción de portainjertos cítricos son de los principales problemas en la producción de plántulas, aunado al hecho de que estos materiales poseen pH alcalino. El objetivo de este trabajo fue evaluar el efecto de sustratos compuestos de acícula de Pinus sp. y un sustrato comercial alcalino a diferentes concentraciones sobre el crecimiento y desarrollo del portainjerto Poncirus trifoliata (L.) Raf. Se evaluó el desarrollo de ‘Trifoliata’ en distintas mezclas (v:v) de un sustrato comercial (Vida®) a base de corteza de eucalipto y acículas de Pinus sp. (0, 25, 50, 75 y 100 %) con dos granulometrías (3.5 y 8.0 mm). El diseño experimental fue en bloques al azar con 10 tratamientos de siete plantas cada uno y cuatro repeticiones. Durante el desarrollo de los portainjertos se monitoreó el pH, la conductividad eléctrica y la estabilidad de los sustratos, la masa seca de la parte aérea, raíces y tallo, además del crecimiento y desarrollo vegetativo. El aumento de la proporción de acículas en la mezcla con sustrato alcalino redujo el pH, la conductividad eléctrica y la densidad. Los tratamientos con acícula de 3.5 mm mostraron mayor estabilidad que los de 8 mm. El uso de 25 % de acícula proporcionó mejores resultados en comparación con el de 0 % (solo sustrato alcalino); no obstante, se detectó la necesidad de un sistema de fertilización y riego específico para cada tratamiento, ya que cada sustrato nuevo posee características físicas y químicas propias.