Jaquelini Luber

Cytotoxic and phytotoxic effects of the main chemical components of spent pot-liner: A comparative approach

Spent pot-liner (SPL) is a hazardous solid waste produced by the aluminum industry. Although its composition may vary, fluoride and cyanide salts as well as aluminum are predominant components. A seed-germination and root-elongation test was performed with Lactuca sativa seeds as a test system. SPL induced decrease of seed germination rate and root elongation. The concentration of 26.5g/L SPL was established from a regression curve as the IC50 (inhibition concentration 50%). Through chemical analyses, the concentrations of fluoride, cyanide and aluminum in SPL solutions of 26.5g/L (IC50), 39.75g/L (1.5IC50) and 13.25g/L (0.5IC50) were determined. Further, a cell-cycle test was conducted with root tips of L. sativa exposed to these same SPL solutions. All test chemicals presented toxic effects on meristematic cells of L. sativa. Aluminum was identified as the SPL component mainly responsible for reduction of the mitotic index. Chromosomal alterations resulted from the interactions among the three main chemical components of SPL, without a clear predominantly responsible agent. Induction of condensed nuclei was mainly due to effects of aluminum and fluoride, and may serve as an indicator of induced cell death.

List of angiosperm species in an Atlantic Forest fragment reveals collection gaps in Espírito Santo state, Brazil

This study presents a list of angiosperm species in an Atlantic Forest fragment in the southern portion of Espirito Santo state, Brazil, a region that represents a collection gap within the Atlantic Forest. The studied site is a relatively small fragment of 144 ha located within a conservation unit, the Mata das Flores State Park. The site belongs to a conservation priority area for the Atlantic Forest in Espirito Santo, and is under strong anthropic pressure. Of the 239 species listed here, 21 are new records for the state, eight are endemic, and 20 figure either in the country’s or the state’s Red Lists of endangered species. Rubiaceae and Piperaceae were the families with the highest number of species. We show that small fragments that were never inventoried before can reveal a relatively large number of threatened species and that collection gaps need to be filled in order to refine our understanding about conservation priorities within the Atlantic Forest Biome.

Accelerated aging test to evaluate the quality of crambe (Crambe abyssinica Hochst - Brassicaceae) seed physiology

Este estudio tuvo como objetivo evaluar la eficacia de la prueba de envejecimiento acelerado, para determinar los efectos fisiologicos de semillas Crambe abyssinica Hochst, un monton de dos cosechas (2009 y 2010). Se evaluaron: contenido de agua, la germinacion y el vigor por el indice de velocidad de la germinacion, envejecimiento acelerado a 41, 43 y 45 °C durante periodos de 24, 48, 72 y 96 horas, el peso fresco y el peso seco. El experimento se llevo a cabo en el esquema factorial 2x3x5 (mucha x temperatura x tiempo de exposicion), en un diseno completamente al azar, con cuatro repeticiones de 25 semillas. El peso fresco y peso seco no son eficientes para diferenciar la calidad fisiologica de las semillas de Crambe abyssinica. Las influencias de envejecimiento acelerado, de manera similar, el porcentaje de germinacion y el vigor, con una mayor sensibilidad cuando las semillas son tratadas con temperaturas de 41 o 43 °C durante 72 h, lo que indica un papel prometedor para la estratificacion de la calidad fisiologica de la semilla crambe de lotes con germinacion similar.

GERMINAÇÃO IN VITRO DE Crambe abyssinica HOCHST

A germinacao in vitro para Crambe abyssinica Hochst e importante tanto para a propagacao massal, quanto como ferramenta para aplicacao de outras tecnicas biotecnologicas. O objetivo deste trabalho foi avaliar os efeitos de diferentes meios de cultura, condicoes fisicas da semente e condicoes de luminosidade na germinacao in vitro de crambe. O experimento foi conduzido em esquema de parcelas sub-subdivididas, tendo nas parcelas as condicoes luminosas (presenca ou ausencia de luz), nas subparcelas os meios de cultura (MS, WPM e B5) e nas sub-subparcelas as condicoes fisicas da semente (presenca ou ausencia de pericarpo). A porcentagem de germinacao foi maior nos meios B5 e WPM, com medias de 99,37% e 97,50%, respectivamente, independente da luz e das condicoes fisicas da semente. Os maiores valores de IVG foram observados tambem nesses meios com media de 3,87 na ausencia de luz em sementes sem pericarpo. O comprimento da parte aerea foi influenciado pela composicao do meio de cultura e condicao luminosa, em que, os meios B5 e WPM apresentaram os maiores valores na ausencia de luz, 13,2 e 11,7 cm, respectivamente. Os comprimentos das raizes foram significativamente maiores nos meios MS e B5, com medias de 6,8 e 5,0 cm, respectivamente, em relacao ao meio WPM, cuja media foi de 3,5 cm. Para as variaveis avaliadas, as condicoes mais favoraveis a germinacao e desenvolvimento das plantas in vitro sao em meio B5 ou WPM, na presenca ou ausencia de pericarpo e na presenca de luz.