Eduardo Fontes Araujo

O grão-de-bico (Cicer arietinum L.) é uma leguminosa de grande importância, sobretudo para a saúde, sendo fonte de proteínas, carboidratos, minerais, vitaminas e fibras. Suas sementes podem apresentar diferenças na variabilidade dimensional, sendo importante a padronização por tamanho, com o intuito de facilitar a operação de semeadura e permitir a obtenção de uma população de plantas capaz de propiciar os melhores rendimentos por área. Objetivou-se com o presente trabalho estudar o efeito do tamanho das sementes de grão-de-bico, cultivar BRS Cicero, na sua qualidade fisiológica. Para isso, as sementes foram classificadas em quatro classes de tamanho, com auxílio de quatro peneiras de crivo circular, com 10, 9, 8 e 7 mm de diâmetro. Portanto, os tratamentos foram constituídos por quatro classes de tamanhos de sementes e um lote sem classificação (Controle). Para comparação, efetuaram-se as seguintes análises: teor de água, peso de 1000 sementes, teste de germinação, teste de condutividade elétrica, emergência em areia, índice de velocidade de emergência, envelhecimento acelerado e teste de tetrazólio. O delineamento experimental utilizado foi inteiramente casualizado, com os dados submetidos à análise de variância e a comparação entre as médias realizadas pelo teste de Tukey a 5% de probabilidade. As sementes de grão-de-bico da classe 7 apresentaram menor germinação e vigor. As sementes de grão-de-bico da classe 10 apresentaram elevados índices de danos mecânicos. Recomenda-se a utilização de sementes classificadas em peneiras 8 e 9 milímetros.

Superabsorbent polymers (SAP) enhance water retention and facilitate seed emergence, though studies predominantly use high-quality water, neglecting SAP performance with alternative sources like sanitary sewage. Addressing the imperative to reduce fresh water demand, especially in water-scarce regions, SAP and sanitary sewage emerge as potential agricultural alternatives, partially fulfilling crop water and nutritional needs. This study assessed the impact of SAP and synthetic sanitary sewage (SSS) on substrate attributes and cowpea emergence in a randomized factorial design (8 x 2), incorporating varying SAP doses (0–0.14%) and hydration sources (SSS and distilled water). Cowpea was cultivated in polystyrene trays under controlled conditions. While SAP and SSS augmented water retention, total dissolved solids, pH, and electrical conductivity (ECse) also increased. Increased ECse negatively affected cowpea germination, emergence speed index (ESI), and time to 50% emergence. In conclusion, applying SAP near cowpea seeds impeded emergence, warranting the exploration of alternative strategies. Despite the rise in ECse, SSS demonstrated benefits for germination, establishing itself as a viable water source for cowpea emergence. This study underscores the necessity for further research into SAP applications and recognizes synthetic sanitary sewage as a promising, water-conserving source for sustainable cowpea growth. Keywords: available water; germination; hydrogel; sowing; wastewater. Polímeros superabsorventes e esgoto sanitário alteram a disponibilidade hídrica na fase de emergência do feijão-caupi RESUMO: Os polímeros superabsorventes (SAP) aumentam a retenção hídrica e emergência das sementes, embora estudos utilizem predominantemente água de boa qualidade, negligenciando o desempenho do SAP com fontes alternativas como o esgoto sanitário. Respondendo ao imperativo de reduzir o consumo de água doce, especialmente em regiões com escassez hídrica, SAP e esgoto sanitário surgem como potenciais alternativas agrícolas. Neste estudo avaliou-se SAP e esgoto sanitário sintético (SSS) nos atributos do substrato e na emergência do feijão-caupi em delineamento fatorial casualizado (8x2), incorporando diferentes doses de SAP (0–0,14%) e fontes hídricas (SSS e água destilada). Cultivou-se feijão-caupi em bandejas de poliestireno sob condições controladas. SAP e SSS aumentaram a retenção hídrica, total de sólidos dissolvidos, pH e condutividade elétrica (ECse). O aumento da ECse reduziu a germinação do feijão-caupi, velocidade de emergência e tempo para emergência de 50% das sementes. Conclui-se que o SAP aplicado próximo das sementes prejudica a emergência do feijão-caupi, justificando a exploração de estratégias alternativas. SSS demonstrou benefícios para a germinação, estabelecendo-se como fonte hídrica viável para emergência do feijão-caupi. Este estudo destaca a necessidade de maiores investigações sobre aplicações de SAP e reconhece SSS como fonte hídrica para o crescimento sustentável do feijão-caupi. Palavras-chave: água disponível; germinação; hidrogel; semeadura; águas residuárias.

Objective: To evaluate the efficiency of dormancy breaking methods in seeds of C. paulinea and C. Spectabilis. Theoretical reference: Species of crotalaria, such as C. paulinea and C. spectabilis, found in the Brazilian territory, are used as green manure in large crops and vegetable productions. However, the presence of tegumentary hardness in their seeds can result in failures in soil cover, which favor the emergence of weeds. Method/design/approach: The research was carried out at the Laboratório de Análise de Sementes of the Departamento de Agronomia, at the Universidade Federal de Viçosa, Minas Gerais. Twenty treatments were applied to the seeds to break dormancy, using mechanical scarification with 120 grit sandpaper, hot water in an oven at 90 °C for five and seven minutes, and immersion in sodium hypochlorite at four concentrations, 2%, 4%, 6% and 8%, for four times, two, four, six and eight hours. Results and conclusion: The most efficient treatments for breaking this dormancy in both species of crotalaria were scarification with sandpaper and immersion in water at 90±3 °C for seven minutes. Treatments using sodium hypochlorite were not effective in reducing the number of hard seeds. Originality/value: Feasibility of the methods applied to break dormancy in seeds of C. paulinea and C. Spectabilis, since they are used for green manure, and control of Aedes aegypti, among other purposes.

O tratamento de sementes com extratos naturais é uma alternativa viável ao uso de produtos sintéticos que não afetam a qualidade fisiológica de sementes de feijão-caupi. Objetivou-se com o trabalho avaliar a qualidade fisiológica de sementes de feijão-caupi submetidas à aplicação de doses de produtos que apresentam potencial fungicida. Para o tratamento de sementes foram utilizados dois produtos sintéticos (maxim XL e captan – dose recomendada) e cinco extratos naturais (alfavaca, arruda, canela, cidreira e pirolenhoso), aplicando-se doses de 0, 2, 4, 6 e 8 mL Kg-1 de sementes. Os produtos naturais apresentaram alto efeito fungicida, inibindo patógenos que afetam a qualidade fisiológica de sementes de feijão-caupi, em especial o gênero Penicillium. Elevada concentração de aleloquímicos na composição de extratos naturais reduz a germinação e o vigor de sementes. O extrato de alfavaca propicia resultados positivos na germinação e vigor de feijão-caupi.

O presente artigo avaliou a eficácia de extratos naturais no controle de fungos em sementes de feijão-caupi. Objetivou-se com o trabalho avaliar a qualidade sanitária de sementes de feijão-caupi submetidas à aplicação de doses de produtos que apresentam potencial fungicida. Para o tratamento de sementes foram utilizados cinco extratos naturais (alfavaca, arruda, canela, cidreira e pirolenhoso), aplicando-se doses de 0, 2, 4, 6 e 8 mL Kg-1 de sementes. Foi realizado o teste de sanidade nas sementes para verificar quais tipos de fungos contaminavam as mesmas. O delineamento foi o inteiramente casualizado em esquema fatorial (5x5) com quatro repetições, totalizando 100 unidades experimentais. Os resultados mostraram que os extratos naturais de alfavaca, arruda, canela, extrato pirolenhoso e capim cidreira foram eficazes no controle de Aspergillus, Fusarium e Cladosporium. O extrato pirolenhoso e o de capim cidreira foram os mais eficazes no controle de Fusarium. Todos os extratos naturais foram eficazes no controle de Cladosporium a partir da dose de 2 mL kg-1 de sementes.

O uso contínuo de defensivos sintéticos no controle de doenças vegetais faz com que alguns microorganismos adquiram resistência aos princípios ativos. Ademais, com a polurização dos efeitos negativos do uso indiscriminado de defensivos no meio ambiente e na saúde do consumidor tem incentivado a busca por práticas agrícolas mais sustentáveis. As fitopatologias transmitidas por órgãos de propagação vegetativa representam um desafio na produção sustentável de alimentos, sendo o uso de sementes sadias a medida mais eficaz para o controle da disseminação de fitopatógenos e da contaminação de novas áreas. O controle alternativo dessas doenças a partir de óleos essenciais extraídos de plantas medicinais tem sido cada vez mais explorado. Além de apresentarem fungitóxicidade cientificamente comprovada por diversos estudos, tais subtâncias apresentam amplo espectro de ação e são de fácil acesso aos agricultores. Diante da importância do tema, a presente revisão bibliográfica visa agrupar informações sobre a utilização de óleos essenciais no tratamento sanitário de sementes.

The Brazilian northeastern semi-arid is a region composed of countless microorganisms adapted to extreme conditions, and to ensure their survival, they can produce several biomolecules and develop peculiar mechanisms. The use of microorganisms has been reported as a promising alternative for promoting plant growth through the production of several bioactive molecules, which can replace chemical agents that cause environmental problems. In this study, Bacillus sp. Ar 16 (UFPEDA), isolated from the rhizosphere of Aroeira (Schinus terebinthifolia) from the Caatinga biome, northeastern semi-arid region, was taxonomically characterized through biochemical tests, Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF) and 16S region rRNA such as Bacillus cereus UFPEDA 1060 B (99.86%). In vitro conditions, the B. cereus UFPEDA 1060B strain produced exopolysaccharide (EPS), cellulases, and phosphatases and presented maximum phosphate solubilization of 880 µg.mL -1 . Furthermore, the production of 3.96 to 4.06 µg.mL -1 of indole acetic acid (IAA) in a culture medium supplemented with 5 mM of L-tryptophan was evidenced. IAA and other organic acids were extracted and analyzed by High-Performance Liquid Chromatography (HPLC) at a retention time of 6.2. The studied strain has different mechanisms that can promote plant growth and is also capable of controlling the growth of Fusarium spp. and Colletotrichum spp. The effectiveness of the results presented by this strain demonstrate its biotechnological potential, which can bring benefits to sustainable agriculture with artifices that favor, in addition to plant growth, the cycling of nutrients.

Information about the effect of herbicides on cowpea seed quality is scarce. The objective of this work was to evaluate the effect of using chemical desiccants at pre-harvest on the anticipation of harvest and physiological quality of cowpea seeds of the cultivar BRS-Tumucumaque, before and after storage. Two experiments were conducted: experiment 1 was conducted under a randomized block design, with four replications; the treatments consisted of seven herbicides (carfentrazone-ethyl, saflufenacil, glyphosate, paraquat, flumioxazin, glufosinate-ammonium, and diquat) and a control treatment; anticipation of harvest, and seed water content, germination, and vigor were evaluated. The seeds were stored for six months in controlled environment and not-controlled environment rooms and evaluated for water content, germination, and vigor in Experiment 2, which was conducted in a 7^2+1 factorial arrangement, with four replications; the first factor consisted of the seven herbicides, the second factor was the two storage environments, plus a control treatment. The results showed 3 to 9 days of anticipation of harvest relative to the control. The glufosinate -ammonium herbicide negatively affected seed germination and vigor. The glyphosate herbicide decreased seed germination and vigor after storage. The physiological quality of cowpea seeds at the post -harvest period and after six months of storage was not affected by the carfentrazone-ethyl and flumioxazin herbicides. Paraquat and diquat were the most efficient herbicides for the anticipation of harvest (nine days). Glyphosate and glufosinate -ammonium were the most harmful herbicides to seed physiological quality. The controlled environment room was the most adequate environment for seed conservation.

Crambe is an oilseed plant whose oil is suitable for various industrial purposes, such as production of biodiesel, plastics, rubbers, and cosmetics. There are reports of the rusticity of this species and its potential for growth in arid and semi-arid environments, where water scarcity and soil salinity are common. However, studies regarding the tolerance of its seeds to these stresses and the physiological responses triggered during germination and seedling establishment under these conditions are incipient. The objective of this study was to evaluate the tolerance of crambe seeds to water deficit and salt stress during germination and early seedling development, as well as to investigate the role of antioxidant enzymes on tolerance to these conditions. The seeds were exposed to water and salt stresses and their performance was analyzed. Seed water content, imbibition rate, percentage and speed of germination, and the base water potential for seed germination were evaluated. In the seedlings, the following measurements were made: root and shoot length, fresh and dry matter of roots and shoots, moisture content, and activity of the enzymes superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX). Water deficit and salt stress reduce the water uptake rate of the seeds, the germination and growth of seedlings. The crambe seeds had higher tolerance to salt stress than to water deficit. Absorption of salt and the action of the SOD and CAT antioxidant enzymes are part of the tolerance mechanisms of crambe seeds to salt stress.

Seeds held inside fleshy fruits after harvest can continue metabolically active, the process of maturation is not interrupted, which can promote the increase on germination and vigour. Also, during maturation and fruit after-ripening period, changes in the mechanisms of protection against oxidative damage can occur, including the activity of antioxidant enzymes. The aim of this study was to evaluate the physiological quality and enzymatic activity of antioxidant defense system of Capsicum chinense Jacq. Represented by the Biquinho pepper and Capsicum frutescens L. represented by the Malagueta pepper seeds, collected from fruits at different developmental stages and subjected to post-harvest storage. Fruits harvested at 40, 55 and 70 days after anthesis (DAA) were stored at 25 °C, for 0, 6, 12 and 18 days. Seeds were evaluated for germination and accelerated aging tests. In addition, the activities of superoxide dismutase, catalase and peroxidase were determined. For both species, seed from fruits collected at 70 DAA, presenting red colour, have higher germination and vigour compared to the seeds harvested at 40 and 55 DAA. The harvest of the fruits on this stage is recommended for obtain high quality seeds. The after-ripening of Biquinho pepper seeds harvested at 55 DAA contribute to increase the germination potential of the seed, while for Malagueta seeds this procedure has little benefit. The catalase enzyme has great potential to monitor the physiological quality of Biquinho and Malagueta pepper seeds; low activity of this enzyme in seeds during the fruits after-ripening is related to better physiological quality.