Enviromental temperature and age of seeds in tolerance to thermoinhibition in lettuce genotypes1

ABSTRACT Lettuce seeds usually show germination problems that can be related to dormancy and or thermoinhibition, as well as to the genotype constitution. The knowledge of the temperature at which the thermoinhibition process begins, as well as the influence of the age of the seed on its germination, is extremely important to establish more suitable parameters for the selection of higher genotypes in breeding programs. The objective of this work was to evaluate the seed germination of three lettuce cultivars according to the enviromental temperature and the age of the seeds. The cultivars Everglades (tolerant to thermoinhibition), Luisa (medium tolerant) and Verônica (sensitive) were used. Seeds of each cultivar were evaluated by the standard germination test, first count test, germination speed index and germination test of remaining seeds. The analyses were performed at four environmental temperatures and in seven storage periods after harvest. None of the cultivars showed primary dormancy. The tolerance to thermoinhibition showed by cultivars Everglades and Luisa and the sensitivity of cultivar Verônica were confirmed. The most suitable temperature for differentiating tolerant and sensitive thermoinhibition genotypes occurred from 30.5 ºC and 260 days after harvest

Physiological, isozyme changes and image analysis of popcorn seeds submitted to low temperatures

Abstract: This present study aimed to assess seed quality of popcorn seedlings subjected to low temperatures by examining their physiological changes, enzymes, and images. We used a completely randomized design with four replications in a factorial arrangement with four hybrids (P618, AP6002, AP8202, AP8203) and five temperatures (10, 13, 16, 19 and 25 °C). Their physiological quality was assessed through radicle protrusion, germination, dry mass of seedlings and emergence. We have assessed the images of seedlings through their hypocotyl and root lengths; and through rates of automatic force, uniformity and growth, provided by Groundeye. The isozyme expressions were determined for the catalase (CAT - IUBMB: EC 1.11.1.6), alcohol dehydrogenase (ADH - IUBMB: EC 1.1.1.1), malate dehydrogenase (MDH - IUBMB: EC: 1.1.1.37) and α-amylase (α-AMY - IUBMB: EC 3.2.1.1). Results show that low temperatures cause a negative effect on seed physiological quality in enzyme expression of CAT, ADH, MDH and α-AMY and on the performance of seedlings. These alterations compromise seed quality. Hybrids AP6002 and AP8203 should be recommended for sowing at up to 16 °C. The Groundeye software was efficient in the analysis of popcorn seedlings and in for the assessment of seed quality when submitted to low temperatures

Physiological, isozyme changes and image analysis of popcorn seeds submitted to low temperatures

<div><p>Abstract: This present study aimed to assess seed quality of popcorn seedlings subjected to low temperatures by examining their physiological changes, enzymes, and images. We used a completely randomized design with four replications in a factorial arrangement with four hybrids (P618, AP6002, AP8202, AP8203) and five temperatures (10, 13, 16, 19 and 25 °C). Their physiological quality was assessed through radicle protrusion, germination, dry mass of seedlings and emergence. We have assessed the images of seedlings through their hypocotyl and root lengths; and through rates of automatic force, uniformity and growth, provided by Groundeye. The isozyme expressions were determined for the catalase (CAT - IUBMB: EC 1.11.1.6), alcohol dehydrogenase (ADH - IUBMB: EC 1.1.1.1), malate dehydrogenase (MDH - IUBMB: EC: 1.1.1.37) and α-amylase (α-AMY - IUBMB: EC 3.2.1.1). Results show that low temperatures cause a negative effect on seed physiological quality in enzyme expression of CAT, ADH, MDH and α-AMY and on the performance of seedlings. These alterations compromise seed quality. Hybrids AP6002 and AP8203 should be recommended for sowing at up to 16 °C. The Groundeye software was efficient in the analysis of popcorn seedlings and in for the assessment of seed quality when submitted to low temperatures.</p></div

Damage caused by different inoculum levels of Aspergillus ochraceus on the vigour of soybean seeds

 A incidência e a severidade de Aspergillus ochraceus pode reduzir a qualidade fisiológica das sementes. Neste trabalho, objetivou-se estudar a qualidade fisiológica de sementes de soja naturalmente infectadas com A. ochraceus. Sementes de soja cv. Conquista com diferentes níveis de inóculo de A. ochraceus foram obtidas por meio da técnica de restrição hídrica e separadas em três níveis (N0, N1 e N2) de acordo com a área superfícial coberta com estruturas fúngicas. Para compor as testemunhas foram retiradas do tratamento N0 duas amostras de 200 sementes de soja, sendo a primeira tratada com os fungicidas carboxin + thiram e a segunda amostra submetida à desinfestação superficial por imersão em solução de hipoclorito de sódio. A seguir, avaliou-se o vigor das sementes por meio do teste de emergência em bandejas e pelo teste de tetrazólio. As avaliações do comprimento de plântulas, massa fresca e massa seca da parte aérea e da raiz foram realizadas aos 21 dias após a semeadura. Observou-se redução do índice de velocidade de emergência e da emergência de plântulas com níveis de até 50% de inóculo em comparação ao tratamento com fungicida. O comprimento das plântulas (44%), a massa fresca da parte aérea e da raiz (82%), a massa seca da parte aérea (81%) e a massa seca da raiz (76%) também foram reduzidos. Sementes de soja com incidência acima de 50% de A. ochraceus apresentaram perda total do vigor e deterioração dos tecidos.The incidence and severity of Aspergillus ochraceus can reduce seed quality. In this study, we aimed to study the physiological quality of soybean seeds naturally infected with A. ochraceus. Seeds of soybean cv. Conquest with different levels of inoculum of A. ochraceus were obtained by the technique of water and separated into three classes (N0, N1 and N2) according to the constraint surface area covered with fungal structures. The control samples were taken from the N0 treatment, two samples of 200 soybean seeds, the first being treated with fungicides carboxin + thiram and the second sample subjected to surface disinfestation by immersion in a solution of sodium hypochlorite. Next, we assessed the vigour of seeds through the emergency test in trays and the tetrazolium test. The length, seedling fresh and dry weight of shoot and root were evaluated at 21 days after sowing. There was a reduction in the rate of speed of emergence and seedling emergence in the seeds with levels of up to 50 % of inoculum compared to treatment with fungicide. The length of the seedlings (44 %), fresh weight of shoot and root (82 %), dry weight of shoots (81 %) and root dry mass (76 %) were also reduced . Soybean seeds with incidence above 50 % of A. ochraceus showed total loss of vigor and decay of tissues

Qualidade sanitária de sementes de coquinho-azedo (Butia capitata) no Norte de Minas Gerais Health quality of Butia capitata seeds in the north of Minas Gerais, Brazil

O coquinho-azedo (Butia capitata Mart. Becc.) é uma palmeira nativa dos cerrados brasileiros e seus frutos são fonte de alimento para seres humanos e animais. Os objetivos deste trabalho foram identificar e quantificar os microorganismos nas sementes dessa espécie, utilizando análises "blotter test" e meio Batata-dextrose-ágar (BDA). Amostras foram colhidas em Abóboras, distrito de Montes Claros, Minas Gerais (MG) e, em um esquema fatorial 2 x 2, as sementes com e sem endocarpo foram analisadas pelo "blotter test" e BDA, empregando-se o delineamento inteiramente casualisado, com 10 repetições. Essas sementes apresentaram microflora diversificada e a retirada do endocarpo não interferiu na análise microbiológica do coquinho-azedo. Mais espécies de microorganismos foram recuperadas na análise no meio BDA, com predominância de fungos Fusarium spp. e Penicillium spp., independentemente da análise. Portanto, a maior parte da microflora identificada nesse trabalho foi fúngica e o melhor teste foi o crescimento em BDA.Coquinho-azedo (Butia capitata Mart. Becc.) is a Brazilian Cerrado native palm tree. Its fruit is used as food to human and animals. This record aim was to identify the microorganisms in the seeds of this species, using the "blotter test" and potato-dextrose-agar (PDA) medium. Samples were collected in Montes Claros, Minas Gerais State. In a factorial scheme 2 x 2, seeds with or without endocarp, were analysed by blotter test" and BDA, using a randomly designed with ten replications. These seeds presented a diversified microorganism population and endocarp removing did not interfere in coquinho-azedo microbiological analysis. Greater numbers of microorganism species were recovered in PDA medium, and mostly were Fusarium spp. and Penicillium spp. This study concluded that predominantly B. capitata microorganism population was fungus and PDA was better medium

Physiological quality of popcorn seeds assessed by the accelerated aging test

Abstract: Despite the insufficient internal supply of popcorn kernel cultivars, the Brazilian production is continuously increasing. Therefore, searching for tests that offer fast results and reliable information on the physiological potential of the seeds is very important. The objective of this study was to assess the efficiency of the accelerated aging test, by using different times and exposure temperatures, for the evaluation of the physiological quality of popcorn seed lots. Popcorn seeds from three lots of the hybrid AP 8203 were used. For the initial characterization of the lots, the following tests were conducted: seed moisture content, first and final germination count, and field emergence. The accelerated aging test was performed in a 3x4x2 factorial scheme. After aging, the seeds were tested for moisture content, germination, and electrical conductivity. The experiment was carried out in a completely randomized design. The characteristic vigor was affected during aging, as evidenced by the increase in the amount of leachate detected by the electrical conductivity test. Seed lot 3 was most vigorous in the aging test conducted for 48 h at 45 °C. The accelerated aging test at 42 ºC for 48 h provides consistent information to differentiate seed lots of popcorn

Physiological and isozyme alterations in lettuce seeds under different conditions and storage periods

Abstract: The objective of the study was to determine the physiological and isozyme alterations in lettuce seeds submitted to different conditions and storage periods. We used a completely randomized design with four replications in a factorial arrangement with six lettuce cultivars (Everglades, Babá de Verão, Elisa, Grand Rapids, Hortência and Salinas 88) and four storage periods (30, 60, 90 and 120 days), on three storage rooms (15, 25 and 35 ° C). The physiological quality was evaluated by first and final germination count, emergence, and germination and emergence speed indexes. The isoenzyme expression of catalase (CAT), esterase (EST), alcohol dehydrogenase (ADH) and malate dehydrogenase (MDH) were determined. The physiological quality of lettuce seeds was preserved when stored at 15 ° C room temperature. The high room temperatures associated with higher storage periods cause a reduction in physiological quality and alterations in enzymatic patterns of CAT, EST, ADH and MDH. For seeds stored at 15 ° C, there were no physiological changes. The lettuce cultivars, especially Everglades, have different levels of tolerance to storage and isoenzyme expressions

Health and physiological quality of sorghum seeds treated with aqueous extracts and essential oils

Objetivou-se com o presente estudo avaliar a eficiência de extratos aquosos e óleos essenciais na qualidade sanitária e fisiológica de sementes de sorgo da cultivar BR 310. Foram realizados dois experimentos, um utilizando sementes de sorgo tratadas com extratos aquosos de Cinnamomum zeylanicum e Mentha spicata e outro, utilizando óleos essenciais de Ocimum gratissimum e Annona crassiflora. Para o experimento com extratos as concentrações foram 0, 10, 20 e 30% e para os óleos foram 0, 5, 10 e 15 ?L/mL. Foram avaliadas as seguintes características: sanidade de sementes (Blotter test), germinação, primeira contagem de germinação e índice de velocidade de germinação. O delineamento utilizado foi o DIC em esquema fatorial 2 x 4, sendo dois extratos ou dois óleos e quatro concentrações, em ensaios independentes. Várias espécies fúngicas estavam associadas às sementes, sendo o gênero Curvularia a de maior incidência. O extrato aquoso de canela (Cinnamomum zeylanicum) e o óleo essencial de alfavaca cravo (Ocimum gratissimum) reduzem a infestação dos fungos, principalmente de Curvularia, porém apresentam efeito fitotóxico reduzindo a viabilidade e o vigor das sementes de sorgo.The objective of the present study was to evaluate the efficiency of aqueous extracts and essential oils on seed quality of sorghum cultivar BR 310. Two experiments were conducted, one using sorghum seeds treated with aqueous extract of Cinnamomum zeylanicum and Mentha spicata and another using essential oils of Ocimum gratissimum and Annona crassiflora. For the experiment with extracts concentrations were 0, 10, 20 and 30% and for the oils were 0, 5, 10 and 15 ?L/mL. We evaluated the following characteristics: seed health (Blotter test), germination, first count of germination and germination speed index. The design was a DIC in 2 x 4 factorial arrangement, two oils or two extracts with four concentrations, independent testing. Several fungal species were associated with the seed, and the genus Curvularia the most prevalent. The aqueous extract of cinnamon (Cinnamomum zeylanicum) and clove essential oil of basil (Ocimum gratissimum) have shown promise for the treatment of seeds, reducing fungal infestation, especially Curvularia, however have phytotoxic effect reducing the viability and vigor of sorghum seeds