Influência da temperatura e da luz na germinação de sementes de couve-cravinho (Porophyllum ruderale (Jacq.) Cass.)

RESUMO -Conyza canadensis e C. bonariensis são espécies invasoras cujo relato tem sido cada vez mais frequente, dada sua capacidade de desenvolvimento em áreas com palhada, sob sistema de semeadura direta (SSD). A luz é necessária para a germinação de diversas espécies de plantas daninhas, sendo considerado um fator de superação da dormência das sementes. A germinação de sementes sob SSD sofre o efeito da filtragem de comprimentos de onda pela palhada, que podem influenciar diretamente esse processo. O presente trabalho teve por objetivo estudar o efeito de diferentes filtros de luz sobre a germinação de sementes de C. canadensis e C. bonariensis. Foi realizado um experimento em que as sementes das espécies foram colocadas para germinar sobre papel mata-borrão umedecido com água, dentro de caixas gerbox transparentes envolvidas com filtros de luz azul, verde, vermelho, vermelho-distante, transparente e também em caixas de gerbox preta (ausência de luz). Foi avaliada a germinação aos cinco e 10 dias após a semeadura e no final desse período por mais 10 dias, com todos os tratamentos recebendo luz branca. As sementes de ambas as espécies sofrem significativamente o efeito da filtragem de comprimentos de onda, exceto o filtro vermelho, que proporcionou germinação superior à dos demais filtros, sendo inferior apenas ao transparente.Palavras-chave: buva, voadeira, filtro de luz, luz vermelha.ABSTRACT -The weed species Conyza canadensis and C. bonariensis have been increasingly reported, given their capacity to develop under the no-tillage system (NTS). Light is necessary for germination of several weeds, and is considered a factor of seed dormancy break. Seed germination in NTS is affected by light wave length filtering by straw, which can directly influence that process. The aim of this work was to determine the effect of different light filters on seed germination of C. canadensis and C. bonariensis. An experiment was carried out in which the seeds of these species were placed to germinate on blotting paper moistened with distilled water, inside transparent gerboxes involved with blue, green, red, light red and transparent light filters, as well as black gerboxes (light absence). Seed germination was evaluated at 5 and 10 days after sowing and at the end of this period for 10 more days, with all the treatments being under the condition of white light (filter absence). The seeds of both species were significantly affected by wave length filtering, except for the red filter which provided superior germination, inferior only to transparent filter.

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“…Não se usou revestimento para o tratamento com luz branca (testemunha) (Toledo et al, 1993;Lopes et al, 2005;Yamashita et al, 2008).…”

Section: Methodsunclassified

“…A luz tem sido relatada como um importante fator para a germinação de sementes de muitas plantas daninhas (Klein & Felippe, 1991;Toledo et al, 1993;Chachalis & Reddy, 2000;Koger et al, 2004;Nandula et al, 2006;Ikeda et al, 2008;Yamashita et al, 2008).…”

Section: Introductionunclassified

Germinação das sementes de Conyza canadensis e Conyza bonariensis em função da qualidade de luz

2011

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“…A luz tem sido relatada como um importante fator para a germinação de sementes de muitas plantas daninhas (KOGER et al, 2004;NANDULA et al 2006;CANOSSA et al, 2008;IKEDA et al, 2008;VIVIAN et al, 2008;YAMASHITA et al, 2008).…”

Section: Introductionunclassified

Germination of two species of Conyza seeds as a function of the presence or absence of light and interaction with the addition of nitrate and gibberellic acid in the substrate

et al. 2016

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“…Species have different luminosity demands because light is required for the germination of seeds (positively photoblastic seeds) in some species, inhibits the germination process in other (negatively photoblastic seeds) and, in some species, germination occurs either with or without light because the seeds are insensitive to this factor (neutrally photoblastic) (Ferreira and Borghetti, 2004;Yamashita, 2008).…”

Section: Introductionmentioning

confidence: 99%

Optimal conditions for germination of seeds of Epiphyllum oxypetalum

Ortiz¹,

Moritz²,

Oliveira³

et al. 2014

Afr. J. Agric. Res.

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Queen of the night (Epiphyllum oxypetalum), an ornamental cactus, is widespread in many countries. The demand for this species is increasing because esthetic quality of its flowers is appreciated. This study aimed to analyze the influence of temperature, substrate and luminosity on the germination of E. oxypetalum seeds. A completely randomized design with four replications was used in a 3 x 2 x 2 factorial scheme, corresponding to three temperatures (20, 25 and 30°C), two substrates (blotting paper and sand of average particle size) and two luminosity conditions (light and dark). The percentage germination, germination speed index (GSI) and mean germination time (MGT) were evaluated. The 20°C treatment combined with the sand substrate and the presence of light provided favorable conditions for the germination of the seeds of E. oxypetalum, yielding a higher GSI and a shorter MGT; however, the species may be considered as preferentially photoblastic because of its ability to germinate in darkness.

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Influência da temperatura e da luz na germinação de sementes de couve-cravinho (Porophyllum ruderale (Jacq.) Cass.)

Cited by 13 publications

References 11 publications

Germinação das sementes de Conyza canadensis e Conyza bonariensis em função da qualidade de luz

Germinação das sementes de Conyza canadensis e Conyza bonariensis em função da qualidade de luz

Germination of two species of Conyza seeds as a function of the presence or absence of light and interaction with the addition of nitrate and gibberellic acid in the substrate

Optimal conditions for germination of seeds of Epiphyllum oxypetalum

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