Production fields and physiological quality of Panicum maximum jacq. cv. mombasa seeds

The physiological quality of seeds is influenced by the climatic factors of production fields. The identification of the best conditions of P. maximum cv. Mombasa production fields allows the improvement of the seed sector. The aim of this work was to identify which climatic conditions of production fields can affect the physiological quality of P. maximum cv. Mombasa seeds. Nineteen plots from states of São Paulo (six from municipalities of Auriflama and three from Guzolândia) and Goiás (eight from Quirinópolis and two from Serranópolis), were collected by soil sweeping. The following parameters were evaluated: water content, germination rate, first germination count and germination rate index, seedling emergence in sand and field. Completely randomized design was used for all variables, with the exception of seedling emergence in field, since this variable required block design. Means were compared by the Scott-Knott test, at 5% probability. For the identification of the influence of climatic conditions on the physiological quality of seeds, multivariate statistical analysis was applied through Group and Principal Component Analysis. Production fields of Panicum maximum cv. Mombasa seeds presenting maximum temperatures above 32 ºC at flowering and natural fall stages produce seeds of low physiological quality. Production fields in which precipitation and high temperatures occur during natural fall and harvest of P. maximum cv. Mombasa seeds are not favorable to the production of seeds with high physiological quality

Dormancy overcoming in seeds of cajá-manga (Spondias dulcis)

The propagation of ‘cajá-manga’ (Spondias dulcis) is usually performed by seeds. The presence of dormancy is an obstacle for seedling production and the commercial use of its main product, the fruit. This research aimed to evaluate the use of phytoregulators associated with the scarification of the distal region of the embryo in dormancy overcoming and in the standardization of germination of ‘cajá-manga’ seedlings. Endocarps extracted from fruits of six matrices were subjected to the following treatments: control (T1), mechanic scarification in the distal region of the embryonic axis (T2); all following treatments involved scarification and imbibition in a solution of: water for 6h (T3); GA3 (750 mgL-1) for 6h (T4); GA3 (350 mg L-1) for 12h (T5); Cytokinin (750 mg L-1) for 6h (T6); Cytokinin (350 mg L-1) for 12h (T7); GA3 and Cytokinin (750 mg L-1) for 6h (T8); and GA3 and Cytokinin sowing 25 endocarps in expanded polystyrene trays using a washed sand substrate. The following variables were evaluated: emergence, first emergence count, emergence speed index, mean emergence time, shoot and root length of seedlings, and relative emergence frequency. The experimental design was in randomized blocks, with 9 treatments and four replications consisting of 25 endocarps each. The data obtained were subjected to the F Test at a 1% level of probability, as well as to the Scott-Knott method. The use of mechanic scarification in the opposite region of the embryonic axis, followed by the imbibition in a solution of gibberellin + cytokinin at the concentration of 350 mgL-1 for 12 hours is promising for dormancy overcoming in seeds of Spondias dulcis.The propagation of ‘cajá-manga’ (Spondias dulcis) is usually performed by seeds. The presence of dormancy is an obstacle for seedling production and the commercial use of its main product, the fruit. This research aimed to evaluate the use of phytoregulators associated with the scarification of the distal region of the embryo in dormancy overcoming and in the standardization of germination of ‘cajá-manga’ seedlings. Endocarps extracted from fruits of six matrices were subjected to the following treatments: control (T1), mechanic scarification in the distal region of the embryonic axis (T2); all following treatments involved scarification and imbibition in a solution of: water for 6h (T3); GA3 (750 mgL-1) for 6h (T4); GA3 (350 mg L-1) for 12h (T5); Cytokinin (750 mg L-1) for 6h (T6); Cytokinin (350 mg L-1) for 12h (T7); GA3 and Cytokinin (750 mg L-1) for 6h (T8); and GA3 and Cytokinin sowing 25 endocarps in expanded polystyrene trays using a washed sand substrate. The following variables were evaluated: emergence, first emergence count, emergence speed index, mean emergence time, shoot and root length of seedlings, and relative emergence frequency. The experimental design was in randomized blocks, with 9 treatments and four replications consisting of 25 endocarps each. The data obtained were subjected to the F Test at a 1% level of probability, as well as to the Scott-Knott method. The use of mechanic scarification in the opposite region of the embryonic axis, followed by the imbibition in a solution of gibberellin + cytokinin at the concentration of 350 mgL-1 for 12 hours is promising for dormancy overcoming in seeds of Spondias dulcis

Water stress on the physiology of germination and seedling morphoanatomy Myracrodruon urundeuva Fr. All. (Anacardiaceae)

The Caatinga Biome, even with the approach of recent years, is a region lacking of information that enables the understanding of how plants survive on stress conditions. Species that make up this biome, Myracrodruon urundeuva Fr. All. stand out for timber and medicinal properties, suffering for decades, intense and predatory exploitation, leading to compose the official IBAMA list of endangered flora. The aim of this work was to select individuals of M. urundeuva through viability and vigor tests and to evaluate the effect of water stress on seedling emergence of normal and morphoanatomy. For such individuals mastic were selected in three areas of Paraiba State, a municipality of the ray tracing and two in Boa Vista, in which diasporas were collected and sent to the Laboratory of Seed Analysis (LAS) UFPB, Areia-PB. Initially it has proceeded to determine the water content (TA) and the following assessments: Germination test (GT), emergency testing (ET), first count of germination and emergence (FCG and FCE), germination speed index and emergency speed index (GSI and ESI), length and dry weight of seedlings. The methodology for implementing saline accelerated aging was also determined. Thereafter individual diasporas (matrix) more vigorous of the three areas were subjected to water stress under conditions of retention capacity of the soil levels: 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 and 60%. In this step we assessed the TA, TE, PCE, IVE, length and dry weight of roots and shoots of seedlings. To evaluate the morphoanatomy, diasporas mastic were subjected to the same continuous water conditions, described above, and a second temporary water condition. For this, they were initially sown in the soil retention capacity of 60%, then to simulate drought with stopping of watering until obtaining the capacities of 10, 15, 20, 25 and 30% retention. After subjected to continuous and temporary water conditions, morphoanatomical characteristics evaluated were: number of leaves, length and width of the primary, length, width and thickness of the central leaflet leaf; length, width and thickness of the cotyledon; number of stomata in the leaf and cotyledon length and diameter of the stem and root. In the initial evaluation of the seeds was observed that individuals of M. urundeuva germination and vigor have differentiated between the collection areas, as well as within the same area, demonstrating the adaptive plasticity of the species. The accelerated aging test in saline temperature of 41 °C during 24 hours is recommended due to the reduction of fungi, the eleventh individual, the stronger this test. When the eleventh individual diasporas were subjected to water stress, it was found that they have some degree of demand relative to water in the early periods of development. The structural and physiological assessments seedlings have adaptive characteristics for perpetuation over time and space in a natural environment. As for water regimes applied in the evaluation of morphoanatomical characteristics, treatments affected seedling development of mastic, and capabilities between 50 and 60% retention of the best treatments for the production of normal seedlings, for most variables.O Bioma Caatinga, mesmo com o enfoque dos últimos anos, é uma região carente em informações que permita o entendimento de como as plantas sobrevivem a condições de estresse. Das espécies que compõem esse Bioma, Myracrodruon urundeuva Fr. All. destacase pelas propriedades medicinais e madeireiras, sofrendo, ao longo de décadas, intensa e predatória exploração, levando-a compor a lista oficial do IBAMA da flora brasileira ameaçada de extinção. Assim, o objetivo deste trabalho foi selecionar indivíduos de M. urundeuva através de testes de viabilidade e vigor, assim como avaliar o efeito do estresse hídrico na emergência de plântulas normais e na morfoanatomia das mesmas. Para tal, indivíduos de aroeira foram selecionados em três áreas do Estado da Paraíba, uma no município de São João do Cariri e duas em Boa Vista, nos quais os diásporos foram coletados e encaminhados ao Laboratório de Análise de Sementes (LAS) da UFPB, em Areia-PB. Inicialmente procedeu-se a determinação do teor de água (TA) e as seguintes avaliações: Teste de germinação (TG), teste de emergência (TE), primeira contagem de germinação e emergência (PCG e PCE), índice de velocidade de germinação e emergência (IVG e IVE), comprimento e massa seca de plântulas. Também foi determinada a metodologia para execução do teste de envelhecimento acelerado salino. Posteriormente os diásporos do indivíduo (matriz) mais vigoroso das três áreas foram submetidos ao estresse hídrico, em condições de capacidade de retenção do solo nos níveis: 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 e 60%. Nesta etapa avaliou-se o TA, TE, PCE, IVE, comprimento e massa seca da raiz e parte aérea de plântulas. Para avaliação da morfoanatomia, os diásporos de aroeira foram submetidos às mesmas condições hídricas contínuas, descritas anteriormente, e uma segunda condição hídrica temporária. Para isso, os mesmos foram semeados inicialmente na capacidade de retenção do solo de 60%, para em seguida simular o déficit hídrico, com cessamento das regas até a obtenção das capacidades de 10, 15, 20, 25 e 30% de retenção. Após submetidas às condições hídricas contínuas e temporárias, as características morfoanatômicas avaliadas foram: número de folhas, comprimento e largura da folha primária, comprimento, largura e espessura do folíolo central; comprimento, largura e espessura do cotilédone; número de estômatos na folha e no cotilédone, comprimento e diâmetro do caule e da raiz. Na avaliação inicial dos diásporos observou-se que, os indivíduos de M. urundeuva possuem germinação e vigor diferenciados entre as áreas de coleta, assim como dentro de uma mesma área, demonstrando a plasticidade adaptativa da espécie. O teste de envelhecimento acelerado salino na temperatura de 41 ºC durante o período de 24 horas é recomendado devido à redução de fungos, sendo o indivíduo onze, o mais vigoroso por este teste. Quando os diásporos do indivíduo onze foram submetidos ao estresse hídrico, verificouse que os mesmos possuem determinado grau de exigência em relação à água nos períodos iniciais de desenvolvimento. As avaliações fisiológicas e estruturais das plântulas apresentam características adaptativas para perpetuação ao longo do tempo e no espaço em ambiente natural. Quanto aos regimes hídricos aplicados na avaliação de características morfoanatômicas, os tratamentos afetaram o desenvolvimento de plântulas de aroeira, sendo as capacidades entre 50 e 60% de retenção os melhores tratamentos para a produção de plântulas normais, para maioria das variáveis analisadas

Quality of Brosimum gaudichaudii seedlings and seeds collected in two different locations

The seed provenance can interfere with their size, as well as in the growth of saplings and susceptibility to stress. The aim of this study was to evaluate the quality of Brosimum gaudichaudii Trécul seeds and seedlings obtained from two different locations. Seeds were collected in two municipalities in the state of Goiás - Iporá and Jataí, in 2018. Individual seed size mass and dimension, seedling emergence percentage and speed, as well as initial growth, leaf chlorophyll index, biomass and seedling quality index (SQI) were determined. Such parameters were determined at 40, 70, 100, 130, 160 and 190 days after sowing (DAS). Individual size mass and dimension of seed collected in Iporá were superior to those collected in Jataí. Despite this, the seedling emergence percentage and seedling mortality were not affected by the different origins of seeds. As expected, there was increase in height, stem diameter and number of leaves of seedlings during the analyzed period, on the other hand, the chlorophyll index remained constant. The initial growth of seedlings differed between origins. The dry biomass did not vary between seedlings from the different origins, with greater allocation of biomass in roots. The SQI of seedlings produced from seeds collected in Iporá was higher than those collected in Jataí. Despite the quality verified for seeds and seedlings from the two origins, seeds collected in Iporá presented larger dimensions than those collected in Jataí, generating seedlings with greater initial growth and higher quality

Duração do teste de germinação de sementes de Brachiaria humidicola (Rendle) Schweick

The period of 21 days suggested by the Brazilian Rules for Seed Testing for the germination test of B. humidicola seeds seems too long for seed producing companies and laboratories since they depend on the results for decisions concerning the storage or the commercialization of the seed lots. So, the objective of this work was to evaluate the possibility of getting germination results of B. humidicola seeds in a shorter period. The procedures consisted in submitting the seeds to a dormancy breaking treatment and to alternating temperatures during the germination test. Seed samples of nineteen S1 and S2 seed lots were submitted to the following treatments: moistening the germination substratum with 1) deionized water (check treatment), 2) a KNO3 (0.2%) solution, and 3) scarifying the seeds with sulfuric acid for 10 minutes. The germination test was conducted under the conditions of 1) alternating temperatures of 20 and 35 °C and 2) alternating temperatures of 15 and 35 °C both with 8 hours of light. Normal seedlings were evaluated in daily countings. The results showed that the germination test of B. humidicola seeds may be carried out under alternating temperatures of 15 and 35 °C without breaking seed dormancy with a final evaluation of the germination 10 days after the sowing of the seeds.O período de 21 dias recomendado pelas Regras para Análise de Sementes para o teste de germinação de sementes de B. humidicola é considerado excessivo por produtores, comerciantes e laboratórios de análise de sementes, que dependem dos resultados do teste para o controle de qualidade e a comercialização. Desta forma, o objetivo do trabalho foi avaliar a possibilidade de reduzir o período necessário para a condução do teste de germinação de sementes de B. humidicola, estabelecendo o método para superação da dormência e a temperatura ideal. Dezenove lotes de sementes comerciais S1 e S2 recém-recebidos na unidade de beneficiamento foram avaliados quanto à germinação, em quatro subamostras de 100 sementes por tratamento, constituído de: substrato umedecido com água deionizada (testemunha), substrato umedecido com KNO3 (0,2%) e escarificação com ácido sulfúrico por 10 minutos. Para o teste de germinação, foram avaliadas duas condições de temperaturas alternadas (20- 35 ºC e 15-35 ºC), com luz (8h). Para definição do período do teste, foram realizadas contagens diárias de plântulas normais e, para cada tratamento, foram ajustadas curvas para avaliação da germinação. No delineamento experimental, os lotes foram considerados as repetições, obtendo-se as estimativas dos parâmetros do modelo de regressão segmentada para cada tratamento. O teste de germinação de sementes de B. humidicola pode ser conduzido a 15-35 oC, sem tratamento para a superação da dormência, com avaliação final aos 10 dias após a semeadura

The envelope method and substrate wetting in the germination test of onion seeds

ABSTRACT The Rules for Seed Analysis reports the use of a paper envelope in germination tests, but without any description of the exact method. The objective of this study was to evaluate the viability of the envelope method and the optimal level of substrate wetting when performing germination tests of onion seeds. The study was performed in two stages. In the first stage, a batch of seeds was evaluated using two seeding methods (on paper and in a paper envelope) and five levels of substrate wetting with differing amounts of water: 1.5, 2.0, 2.5, 3.0, and 3.5 times the dry mass of the paper. A completely randomized design was used in a 2×5 factorial scheme. In the second stage of the study, the two seeding methods mentioned in the prior were tested in eight seed batches using a completely randomized design and a 2×8 factorial scheme. The degree of moisture, germination, and the first count of germination were evaluated. The time spent for the installation, seeding, counting, and disassembling of the germination test were determined. It was concluded that the envelope method is fit for use in onion seed germination tests. The optimal amount of water to add to the substrate is 2.5 times the dry mass of the paper substrate. The envelope method is fast, practical, and more efficiently uses space within germinator chambers, making it easily incorporable into routine tests within seed analysis laboratories

Determinação da metodologia para o teste de germinação de sementes de Eucalyptus urophylla S. T. Blake (Myrtaceae)

Eucalyptus urophylla S. T. Blake is one of the main eucalyptus species cultivated. However, there are no recommendations for testing its germination pattern. Thus, the objective of this work was to determine the best methodology to conduct seed germination tests for E. urophylla. The study was divided into two steps. In the first, two substrates (on paper and sand) and six temperatures (15, 20, 25, 30, 35ºC, and alternating 20-30ºC, between night and day, respectively) were tested. In the second step, the best substrate was selected based on the first experiment and was tested in two seeds lots and at the six temperatures previously mentioned. Germination, first count, speed index and the average germination time were evaluated. The experiment was in a completely randomized design with four replications and the treatments were arranged in a 2x6 factorial scheme for both steps. When comparing germination between lots, it was observed that lot 1 had a lower performance than lot 2 under extreme temperature conditions. Seed germination tests of E. urophylla should be made at 30 or 35ºC on the paper or sand substrate, with the initial and final counts at four and 10 days after sowing, respectively. Based on this study, more tests should be made with seeds from other lots and populations of E. urophylla to confirm the results.Eucalyptus urophylla S. T. Blake é uma das principais espécies de eucaliptos cultivadas. Entretanto, não existem recomendações para o teste padrão de germinação de E. urophylla. Assim, o objetivo foi determinar a melhor metodologia para a condução do teste de germinação de sementes de E. urophylla. O experimento foi dividido em duas etapas. Na primeira, foram testados dois substratos (sobre papel mata-borrão e areia) e seis temperaturas (constantes de 15, 20, 25, 30, 35ºC e alternada de 20-30ºC, entre noite e dia, respectivamente) na condução do teste de germinação. Na segunda etapa, foi selecionado o substrato mais indicado no experimento anterior e testado em dois lotes, nas seis temperaturas citadas anteriormente. Foram avaliadas a germinação, primeira contagem, índice de velocidade e tempo médio de germinação. O experimento foi realizado em delineamento inteiramente casualizado com quatro repetições e os tratamentos foram dispostos em esquema fatorial de 2 x 6 para ambas as etapas. Na comparação da germinação entre os lotes, observou-se que o lote 1 apresentou menor desempenho do que o lote 2 nas condições de temperaturas extremas. O teste de germinação de sementes de E. urophylla deve ser realizado a 30 ou 35°C com semeadura sobre papel ou areia, e com contagem inicial e final aos quatro e 10 dias após a semeadura, respectivamente. Com base nesta pesquisa, mais testes podem ser realizados, para outros lotes e sementes de E. urophylla de outras procedências, para garantir a confirmação dos resultados

Beneficiamento na qualidade física e fisiológica de sementes de capim-mombaça

RESUMO A semente recebida pelas empresas de gramíneas forrageiras, após a colheita, contém impurezas cuja remoção é realizada por máquinas de beneficiamento. Este procedimento é necessário para a obtenção de sementes dentro dos padrões de qualidade para a comercialização e a semeadura. O objetivo deste trabalho foi avaliar o efeito das etapas de beneficiamento na qualidade física e fisiológica de sementes de Panicum maximum cv. Mombaça, visando à comercialização. As sementes foram amostradas antes do processamento e após a saída da máquina de ventilador e peneiras (descarga das peneiras superior, intermediária e fundo), primeira mesa gravitacional (deriva, descarga superior e intermediária), máquina tratadora e segunda mesa gravitacional (descarga superior, intermediária e inferior). As sementes foram avaliadas quanto ao teor de água, qualidade física (pureza e peso de mil sementes) e fisiológica (germinação, primeira contagem, classificação do vigor de plântulas, envelhecimento acelerado, comprimento de plântulas, emergência de plântulas em campo e índice de velocidade de emergência). O beneficiamento de sementes, na máquina de ar e peneiras e mesa gravitacional é eficiente para o aprimoramento da qualidade física e fisiológica do lote de sementes de P. maximum cv. Mombaça. Para esta espécie o beneficiamento é necessário para atender os requisitos de pureza e germinação estabelecidos pelos padrões de comercialização nacional de sementes