Banco de sementes em cerrado sensu stricto sob queimada e sistemas de cultivo

Ikeda, F. S.; Mitja, Danielle; Vilela, Lourival; Silva, José Carlos Sousa

doi:10.1590/s0100-204x2008000600001

Cited by 34 publications

(36 citation statements)

References 15 publications

(18 reference statements)

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“…The formation of a seed bank represents an important regeneration strategy for many weed species from this family (LECK; SCHÜTZ, 2005). This result corroborates similar studies conducted in other tropical regions, such as those from Kamoshita et al (2010), who observed that 86% of the species present in the seed banks of 22 rice fields from smallholders in Cambodia were from the Cyperaceae family.…”

Section: Discussionsupporting

confidence: 92%

“…The density of 372 viable seeds m -2 found in the weed seed bank assessed in the greenhouse is lower compared to the 22,313 seeds m -2 in lowland areas and 6,768 seeds m -2 in a crop rotation (soybean, fallow, bean) reported by Carmona (1995) Isaac and Guimarães (2008). This is probably due to management practices that the smallholder farmers from Lago Verde County have been using in the past ten years.…”

Section: Discussionmentioning

confidence: 64%

“…In addition to losses from predation, germination failure might have occurred due to periods of soil water stress or to intra-and interspecific competition, as observed by Herault and Hiernaux (2004) in weed seed and population dynamics studies conducted in Africa and also by Isaac and Guimarães (2008) in research conducted on the weed seed bank and emergent flora in agricultural fields in Mato Grosso State, in western Brazil.…”

Section: Discussionmentioning

confidence: 94%

“…When favorable conditions occur, the Lopes et al (2006), Ikeda et al (2008), Isaac and Guimarães (2008), Andrade et al (2009), Costa et al (2009 and Kamoshita et al (2010). However, most of these studies were directed towards agribusiness, with no concern for generating scientific knowledge useful to smallholders.…”

Section: Introductionmentioning

confidence: 99%

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Soil weed seed bank in situ and ex situ at a smallholder field in Maranhão State, northeastern Brazil

2014

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ABSTRACT. The objective of this research was to assess the density, floristic composition, phytosociology and diversity of a soil weed seed bank ex situ by germination in a greenhouse and in situ by weed sampling on a smallholder corn field located in Lago Verde County, Maranhão State. Fifteen pairs of 25 m 2 plots were designated. In half of these plots, 90 soil samples were collected with an open metal template measuring 25 x 16 x 3 cm and placed in a greenhouse to germinate. In the other half, 90 weed samples were collected using the same metal template. We recorded a total of 1,998 individuals from 40 species, 31 genera and 16 families, from which 659 individuals germinated in situ and 1,339 ex situ. Density was higher ex situ, with 372 plants m -2 . The Cyperaceae family had the highest floristic richness with nine species, followed by the Poaceae with six. The dominant species based on the Importance Value Index were Lindernia crustacea (IVI 27.7%) in situ and Scleria lithosperma (IVI 37.0%) ex situ. Floristic diversity was higher ex situ, with H' = 2.66 nats ind -1. These results could help predict infestation potential and could lead to improved weed management strategies in corn-growing areas on smallholdings in Maranhão State, northeastern Brazil.Keywords: cyperaceae, competition, biological invasion, phytosociology, smallholder farmers.Banco de sementes de plantas invasoras no solo in situ e ex situ em área de agricultura de subsistência no Estado do Maranhão, Nordeste do Brasil RESUMO. O objetivo desta pesquisa foi avaliar a densidade, composição florística, fitossociologia e a diversidade no banco de sementes do solo ex situ pelo método de germinação em casa de vegetação e in situ em área de cultivo de subsistência de milho no município de Lago Verde, Estado do Maranhão. Quinze pares de parcelas de 25 m 2 foram alocadas. Na metade destas parcelas, 90 amostras de solos foram retiradas com um gabarito de metal vazado de 25 x 16 x 3 cm e colocadas para germinar em casa de vegetação. Na outra metade, 90 amostras de plantas invasoras foram retiradas com o mesmo gabarito. Foi registrado o total de 1.998 indivíduos de 40 espécies, 31 gêneros e 16 famílias, dos quais 659 indivíduos de 29 espécies germinaram in situ e 1.339 individuos de 29 espécies ex situ. A família Cyperaceae teve a maior riqueza florística com 9 espécies, seguida pela família Poaceae com seis. As espécies dominantes baseado no índice de valor de importância foram Lindernia crustacea (IVI 27,7%) in situ e Scleria lithosperma (IVI 37,0%) ex situ. A diversidade florística foi maior no banco de sementes do solo ex situ com H' = 2,66 nats ind -1 . Estes resultados podem ajudar na previsão de infestações e contribuir para melhorar estratégias de manejo de plantas invasoras em areas de cultivo de subsistência no Maranhão.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 64%

Section: Discussionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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Soil weed seed bank in situ and ex situ at a smallholder field in Maranhão State, northeastern Brazil

2014

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“…Various studies recently conducted in the tropics have been aimed at identifying weed species in crop fields, in pastures and in the corresponding seed banks (Silva & Dias-Filho 2001;Lacerda et al 2005;Begum et al 2006;Lopes et al 2006;Ikeda et al 2008;Isaac & Guimarães 2008;Andrade et al 2009;Costa et al 2009;Kamoshita et al 2010). However those studies were focused on agribusiness rather than on generating scientific knowledge for use in subsistence farming.…”

Section: Introductionmentioning

confidence: 99%

Floristic diversity of the soil weed seed bank in a rice-growing area of Brazil: in situ and ex situ evaluation

2013

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The objective of this study was to compare the ex situ and in situ floristic diversity of the soil weed seed bank of a rice field in northeastern Brazil. In a rice field in the county of Bacabal, located in the state of Maranhão, thirty 25-m 2 plots were laid out. From 15 plots, soil samples (6/plot; n = 90) were taken with a soil probe (25 × 16 × 3 cm) and placed in aluminum trays in the greenhouse. From the remaining 15 plots, weed samples (6/plot; n = 90) were taken with the same soil probe. The number of seeds was estimated by germination. We evaluated the numbers of species and individuals, as well as the density, frequency, abundance and importance value (IV) for each species. Diversity was computed by the Shannon index (H'). We recorded 13,892 individuals (among 20 families, 40 genera and 60 species), of which 11,530 (among 50 species) germinated ex situ and 2,362 (among 34 species) germinated in situ. The family Cyperaceae had the highest number of species (16), followed by Poaceae (10). The dominant species, in situ and ex situ, were Schoenoplectus juncoides (IV=47.4%) and Ludwigia octovalvis (IV=34.8%), respectively. Floristic diversity was higher ex situ (H'=2.66). The information obtained here could help determine the infestation potential of these species, which could lead to improved management strategies.

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Germination of grass species from dry and wet grasslands in response to osmotic stress under present and future temperatures

Souza

Ramos

Barbosa

et al. 2022

American J of Botany

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Premise Seed germination is controlled by the soil microclimate, which is expected to change with the temperature increase and rainfall irregularity predicted for the future. Because changes in soil characteristics directly affect species recruitment, vegetation dynamics and resilience, we investigated how caryopses of native grasses from dry and wet grasslands respond to water stress under current and future temperature regimes. Methods Caryopses were collected from 10 grass species in dry and wet grasslands, subjected or not to a fire event, and tested for germination at increasing osmotic potential (0 to –1.0 MPa) at current (17°/27°C night/day) and future (23°/33°C) simulated temperatures. Results The viability and germination percentages of caryopses from both dry and wet grassland species were progressively reduced as osmotic stress increased, irrespective of temperature regime. The viability of caryopses from wet grassland species was reduced under the future temperature regime, irrespective of osmotic potential. The slow germination of caryopses of dry grassland species at the present temperature regime was absent when they were incubated in the future temperature regime. Conclusions More intense water stress reduced the survival of caryopses for both dry and wet grassland grass species. The predicted future temperature regime reduced the viability of wet grassland species and altered the germination strategy of dry grassland species. These results indicate that increasing water stress and temperature predicted for the future may compromise the recruitment potential of dry and wet grassland species and directly impact the dynamics and resilience of these ecosystems.

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Banco de sementes em cerrado sensu stricto sob queimada e sistemas de cultivo

Cited by 34 publications

References 15 publications

<b>Soil weed seed bank <i>in situ</i> and <i>ex situ</i> at a smallholder field in Maranhão State, northeastern Brazil

<b>Soil weed seed bank <i>in situ</i> and <i>ex situ</i> at a smallholder field in Maranhão State, northeastern Brazil

Floristic diversity of the soil weed seed bank in a rice-growing area of Brazil: in situ and ex situ evaluation

Germination of grass species from dry and wet grasslands in response to osmotic stress under present and future temperatures

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