-Seed dormancy is a phenomenon that affects the distribution of plant species in time. However, it may slow germination and consequently hinder seedling production in nurseries. Many seeds of forest species of the Fabaceae family, such as Libidibia ferrea (Brazilian ironwood), have physical dormancy caused by impermeability of the seed coat to water. Therefore, the aim of this study was to evaluate the physiological, physical, and morpho-anatomical characteristics of L. ferrea seeds before and after application of different treatments for overcoming dormancy. We evaluated the imbibition curves, germination percentage, germination speed index (GSI), the force required to puncture the micropylar region, and morphoanatomical changes through images obtained from a scanning electron microscope (SEM) before and after application of treatments for overcoming dormancy. L. ferrea seeds immersed in sulfuric acid show a triphasic pattern of imbibition. The required force to puncture the micropylar region of L. ferrea seeds is less for both the treatment with boiling water and for treatments with sulfuric acid. In addition, the required force to puncture the micropylar region decreases during imbibition of the seeds after application of sulfuric acid. The time of application of sulfuric acid influences the thickness of the material removed from the macrosclereid layer of the seed coat.Index terms: Libidibia ferrea ((Mart. ex Tul.) L.P. Queiroz), forest seeds, physical dormancy. Alterações fisiológicas, físicas e morfo-anatômicas em sementes deLibidibia ferrea após superação de dormência RESUMO -A dormência de sementes é um fenômeno que influencia a distribuição das espécies de vegetais no tempo. Porém, pode retardar a germinação, e consequentemente, dificultar a produção de mudas em viveiros. Muitas sementes de espécies florestais da família Fabaceae, como Libidibia ferrea (pau-ferro), apresentam dormência física causada pela impermeabilidade do tegumento à água. Portanto, o objetivo neste trabalho foi avaliar as características fisiológicas, físicas e morfo-anatômicas das sementes de L. ferrea antes e após aplicação de diferentes tratamentos para superação de dormência. Avaliaram-se as curvas de embebição, a porcentagem de germinação, o índice de velocidade de germinação, a força requerida para ruptura da região micropilar e as alterações morfo-anatômicas por meio de imagens obtidas de microscópio eletrônico de varredura antes e após a aplicação de tratamentos para superação de dormência. Sementes de L. ferrea imersas em ácido sulfúrico apresentam padrão trifásico de embebição. A força de ruptura da região micropilar de sementes de L. ferrea é menor tanto para o tratamento com água fervente quanto para os tratamentos com ácido sulfúrico. Além disso, a força necessária para ruptura da região micropilar diminui durante a embebição das sementes após aplicação de ácido sulfúrico. O tempo de aplicação de ácido sulfúrico influencia na espessura removida da camada de macroesclereídios do tegumento das sementes.Termos par...
-Seed germination is dependent on abiotic factors, temperature being one of the main ones, whose influence causes seed damage under extreme conditions. The aim of the present study was to investigate the effect of different temperatures during germination of D. nigra seeds and their physiological and biochemical implications. We assessed germination percentage and production of superoxide anion (O 2 -) and hydrogen peroxide (H 2 O 2 ) in seeds subjected to temperatures of 5, 15, 25, 35 and 45 ºC for different periods of time. Hydration is promoted at 45 ºC and inhibited at 5ºC, without germination in either, whereas it is minimal at 15 °C and at a maximum level at 25 °C. Superoxide production increases at higher temperatures (25 and 35 ºC) after 72 hours of hydration, coinciding with the beginning of radicle protrusion. Production of hydrogen peroxide decreases at all temperatures, except for 5 ºC, with values near each other at temperatures of 15, 25, and 35 ºC, where there was radicle protrusion. Termos para indexação: floresta, fisiologia, bioquímica, jacarandá-da-bahia.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.