RESUMO A canola é uma oleaginosa de grande importância econômica para alimentação, a produção de rações e o biodiesel, demandando sementes de alta qualidade para assegurar germinação, uniformidade e produtividade. Este estudo avaliou o teste de envelhecimento acelerado para determinar o vigor das sementes, além de analisar alterações anatômicas e histoquímicas após envelhecimento artificial. Foram utilizados cinco lotes de sementes da cultivar Diamond, avaliados por testes de germinação, emergência de plântulas e frio. O teste de envelhecimento acelerado foi realizado pelo método tradicional e com solução saturada utilizando NaCl e KCl, a 41 °C, por 24 a 96 horas. Cortes de sementes foram corados para análise anatômica e histoquímica. O método tradicional resultou em maior deterioração das sementes, enquanto solução saturada com KCl por 24h preservou a qualidade fisiológica, apresentando padrões celulares e de coloração similares às sementes não envelhecidas. Após 96 horas no método tradicional, observou-se desorganização celular e redução de proteínas e lipídios. O envelhecimento acelerado com solução saturada de KCl a 41 °C por 24h mostrou-se eficaz na avaliação do vigor das sementes sem comprometer sua integridade fisiológica.

ABSTRACT Canola is an oilseed crop of significant economic importance for food, feed production, and biodiesel, requiring high-quality seeds to ensure germination, uniformity, and productivity. This study evaluated the suitability of the accelerated aging test to assess seed vigor, as well as anatomical and histochemical alterations after artificial aging. Five seed lots of the Diamond cultivar were evaluated using germination, seedling emergence, and cold tests. The accelerated aging test was conducted using the traditional method and saturated solution with NaCl and KCl at 41 °C for 24 to 96 hours. Seed sections were stained for anatomical and histochemical analysis. The traditional method resulted in more significant seed deterioration, while the saturated solution with KCl for 24 hours preserved physiological quality, presenting cellular and staining patterns similar to non-aged seeds. After 96 hours in the traditional method, cellular disorganization and reduced protein bodies and lipid droplets were observed. The accelerated aging test using saturated solution with KCl at 41 °C for 24 hours proved effective in assessing seed vigor without compromising physiological integrity.

Abstract Contamination of water sources due to herbicide is of great concern. Clomazone is a pesticide with a high contamination potential which could possibility lixiviate to water streams. Changes caused by residual herbicide include flora modifications which are generally detrimental for some species. The lack of morphological studies performed in aquatic plants exposed to herbicide-contaminated environments has encouraged the development of our research. For the first time, we present a study that aimed to evaluate leaf injuries visible to the naked eye as well as microscopical effects which may be caused by clomazone on Pistia stratiotes. Pistia stratiotes was subjected to five concentrations of clomazone. Our analysis showed leaf injuries, especially after 15 days of clomazone application. Hormesis was observed when the water lettuce was subjected to the lower concentrations. Total leaf area showed increase following by reduction while injured until reaching the highest concentration. Although the concentrations of clomazone tested in our study are not lethal to water lettuce, such herbicide have still caused morphoanatomical damages on leaves which advocates for the use of P. stratiotes as a bioindicator of the presence of herbicides such as clomazone in water.

Resumo: O objetivo deste trabalho foi avaliar os efeitos de diferentes arranjos de plantas de eucalipto sobre as características morfoanatômicas de lâminas foliares de plantas de capim 'Marandu' [(Urochloa brizantha (Syn. Brachiaria brizantha)] cultivadas em sistemas agrossilvipastoris. O experimento foi estabelecido em condições de campo, em um delineamento de blocos ao acaso, com quatro repetições, em que as parcelas foram representadas pelos espaçamentos de plantio de eucalipto (12x2 e 12x4 m), e as subparcelas, pela distância entre o capim 'Marandu' e as fileiras de eucalipto (6, 4 e 2 m). Adicionou-se um controle apenas com capim 'Marandu', cultivado a sol pleno. As variáveis de anatomia foliar do capim 'Marandu' foram avaliadas quanto à interferência do sombreamento pelas árvores. A distância entre as plantas de capim 'Marandu' e as linhas de eucalipto interferiram na anatomia da lâmina foliar da forragem, e as maiores modificações ocorreram nas medidas lineares e proporções teciduais nos arranjos com maior densidade de eucalipto. A interferência do sombreamento pelo eucalipto nas características anatômicas das folhas de capim 'Marandu' depende do arranjo adotado. Isto ocorre em razão da adaptação do capim à baixa incidência de luz, com a consequente redução de sua atividade fisiológica e crescimento.

Abstract: The objective of this work was to evaluate the effects of different arrangements of eucalyptus plants on the morphoanatomical characteristics of leaf blades of 'Marandu' grass [(Urochloa brizantha (Syn. Brachiaria brizantha)] plants cultivated in agrosilvopastoral systems. The experiment was set in field conditions in a randomized complete block design with four replicates, in which the plots were represented by planting spacings of eucalyptus (12x2 and 12x4 m), and the subplots, by the distance between 'Marandu' grass and eucalyptus rows (6, 4, and 2 m). A control was added, composed by 'Marandu' grass cultivated in full sun. Variables of the leaf anatomy of 'Marandu' grass were evaluated for shading interference by trees. The distance of 'Marandu' grass plants from the eucalyptus lines interfered with the leaf blade anatomy of the forage, and the highest modifications occurred in linear measures and tissue proportions in the arrangements with the highest eucalyptus density. The shading interference of eucalyptus on the anatomical characteristics of leaf blades of 'Marandu' grass depends on the adopted arrangement. This occurs due to the grass adaptation to the low-light incidence, with a consequent reduction in its physiological activity and growth.

Cyrtopodium glutiniferum is an endemic orchid of Brazil with potential medicinal and ornamental applications. As mycorrhizal fungi are essential for the initiation of the orchid life cycle, the aim of this study was to determine the strains of mycorrhizal fungi suitable for seed germination and protocorm development of C. glutiniferum and to characterize the symbiotic development of protocorms. Seeds of C. glutiniferum were inoculated with nine mycorrhizal fungi, Epulorhiza spp., Ceratorhiza spp., Rhizoctonia sp., originally isolated from Brazilian neotropical orchids. Only Epulorhiza isolates promoted seed germination and protocorm development. Three Epulorhiza isolates (M1, M6 = E. epiphytica, M20 = Epulorhiza sp.) promoted protocorm development until leaf production at 63 days. The protocorms are comprised of parenchyma cells delimited by a unistratified epidermis; the parenchyma cells of the upper part of the protocorms are smaller than those located more towards the base. Intact and digested pelotons were observed inside of protocorms implying that the seedlings were capable of mycotrophy. Additionally, the development of a bud primordium only occurred after colonization by fungus. This study suggests that C. glutiniferum has a preference for strains of Epulorhiza and that fungus digestion is essential to protocorm development.