Sementes recalcitrantes: intolerantes a baixas temperaturas? Embriões recalcitrantes de Inga vera Willd. subsp. affinis (DC.) T. D. Penn. toleram temperatura sub-zero
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Data
2008-06-01
Autores
Bonjovani, Marcio R. [UNESP]
Barbedo, Claudio J.
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Botânica de São Paulo
Resumo
Sementes recalcitrantes são intolerantes à dessecação e a baixas temperaturas, que são as principais formas de conservação de sementes e, portanto, são de difícil armazenamento. Inga vera subsp. affinis produz sementes denominadas recalcitrantes, uma vez que não toleram redução do teor de água para valores inferiores a 35%. Neste trabalho é demonstrada a tolerância desses embriões a temperatura de -2 ºC. Embriões de I. vera de diferentes estádios de maturação foram armazenados por até 45 dias nas temperaturas de 8 ºC a -18 ºC, com ou sem secagens prévias até -4,0 e -6,0 MPa. Os resultados permitiram observar que, embora nenhum tratamento tenha proporcionado resistância à temperatura de -18 ºC, a secagem dos embriões maduros a -4 MPa proporcionou maior tolerância à redução de temperatura até níveis de congelamento da água (-2 ºC).
Recalcitrant seeds are intolerant to both desiccation and low temperatures, the most important mechanisms of seed conservation, consequently their storage is difficult. Inga vera subsp. affinis produces the so-called recalcitrant seeds, since they do not survive to water content lower than 35%. In this work it is demonstrated that these seeds are tolerant to temperatures as low as -2 ºC. Embryos of I. vera of different stages of maturity were stored at temperatures varying from 8 to -18 ºC for until 45 days. Non-dried embryos and both dried to -4 MPa and -6 MPa were stored. Results showed that, despite all embryos died at -18 ºC, some cold tolerance was obtained by mature embryos when stored at -2 ºC, as long as they are dried to -4 MPa.
Recalcitrant seeds are intolerant to both desiccation and low temperatures, the most important mechanisms of seed conservation, consequently their storage is difficult. Inga vera subsp. affinis produces the so-called recalcitrant seeds, since they do not survive to water content lower than 35%. In this work it is demonstrated that these seeds are tolerant to temperatures as low as -2 ºC. Embryos of I. vera of different stages of maturity were stored at temperatures varying from 8 to -18 ºC for until 45 days. Non-dried embryos and both dried to -4 MPa and -6 MPa were stored. Results showed that, despite all embryos died at -18 ºC, some cold tolerance was obtained by mature embryos when stored at -2 ºC, as long as they are dried to -4 MPa.
Descrição
Palavras-chave
armazenamento, congelamento, espécie tropical, germinação de semente, recalcitrante, freezing, recalcitrant, seed germination, storability, tropical tree
Como citar
Brazilian Journal of Botany. Sociedade Botânica de São Paulo, v. 31, n. 2, p. 345-356, 2008.