Aplicação do teste de raios x no estudo da morfologia interna e da qualidade fisiológica de aquênios de arnica (Lychnophora pinaster Mart.)
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Data
2009-01-01
Autores
Melo, Paulo Régis Bandeira de [UNESP]
Oliveira, João Almir
Carvalho, Maria Laene Moreira de
Guimarães, Renato Mendes
Carvalho, Bruno de Oliveira
Título da Revista
ISSN da Revista
Título de Volume
Editor
Associação Brasileira de Tecnologia de Sementes (ABRATES)
Resumo
O teste de raios X vem sendo empregado em programas de qualidade e como auxiliar nos estudos morfológicos e fisiológicos de sementes de diversas espécies. A arnica (Lychnophora pinaster Mart.) é uma espécie medicinal que apresenta um número elevado de aquênios cheios ou mal formados por ocasião da frutificação, o que dificulta a produção de sementes necessária para o suprimento de uma demanda cada vez maior, pela indústria farmacêutica. Para verificar o efeito do estádio de maturação de aquênios de arnica na qualidade fisiológica das sementes e a eficiência do teste de raios X na separação de sementes mal formadas, foram coletados, no mês de dezembro de 2003, aquênios provenientes de uma população de plantas do município de Itumirim, MG. Na coleta, foram considerados os capítulos cujos aquênios apresentavam o papus interno aderido, estádio menos maduro e com papus interno ausente, aquênios mais maduros já em dispersão. Após a coleta, os aquênios foram submetidos à secagem, pré-limpeza e separados com auxílio de um soprador vertical. Os aquênios foram dispostos em placas de acrílico transparente sobre fita adesiva de dupla face, radiografados e separados em três categorias, de acordo com a morfologia interna visualizada na radiografia em cheios, mal formados e vazios; em seguida foram submetidos ao teste de germinação por um período de 90 dias, em BOD regulada à temperatura alternada de 20-30ºC e fotoperíodo de 12 horas. Foram avaliados o índice de velocidade e a porcentagem final de germinação. Os aquênios remanescentes foram submetidos ao teste de tetrazólio para verificação da sua viabilidade. O teste de raios X na intensidade de 30Kv por 45 segundos é eficiente na separação dos aquênios conforme sua morfologia interna. No estádio de maturação dos capítulos com aquênios sem o papus interno são obtidas sementes de arnica de qualidade fisiológica superior.
The X-ray test is used in seed quality programs to assist morphological and physiological evaluations. Arnica (Lychnophora pinaster Mart.) is considered a medicinal species that has a remarkable number of badly formed seeds at the time of fruit dispersion. Thus, the objective of this study was to verify the influence of the maturation stages on the physiological quality of Arnica seeds by the X-ray test. The seeds used were collected in December 2003 from a natural population in the district of Itumirim, State of Minas Gerais, Brazil. At seed collection the following were considered: the capitulum in which the seeds showed jointed internal papus, less mature stage, without internal papus and seeds that were dispersing. After collection the seeds were dried, cleaning and separated with a vertical blower. The seeds were placed in acrylic transparent plates, radiographed and separated into three categories, full, badly formed and empty seeds according to the internal morphology observed on the radiographs. The time and intensity used during the X-ray test were previously tested. Four replications of 50 seeds for each treatment were used. The seeds were placed in a gerbox on paper towel and kept for 90 days in an incubator (BOD) adjusted at alternating temperature (20-30ºC) and 12-hour photoperiod. The parameters evaluated were speed of germination and final germination percentage. The remaining seeds were subjected to the tetrazolium test to verify seed viability. The X-ray test was shown to be effective for separating the seeds into categories based on their internal morphology. The radiation of 30Kv for 45 seconds allowed visualization of the internal structures of the seeds. The capitulum maturation stage with seeds without internal papus at the time of dispersion was the best for seed collection.
The X-ray test is used in seed quality programs to assist morphological and physiological evaluations. Arnica (Lychnophora pinaster Mart.) is considered a medicinal species that has a remarkable number of badly formed seeds at the time of fruit dispersion. Thus, the objective of this study was to verify the influence of the maturation stages on the physiological quality of Arnica seeds by the X-ray test. The seeds used were collected in December 2003 from a natural population in the district of Itumirim, State of Minas Gerais, Brazil. At seed collection the following were considered: the capitulum in which the seeds showed jointed internal papus, less mature stage, without internal papus and seeds that were dispersing. After collection the seeds were dried, cleaning and separated with a vertical blower. The seeds were placed in acrylic transparent plates, radiographed and separated into three categories, full, badly formed and empty seeds according to the internal morphology observed on the radiographs. The time and intensity used during the X-ray test were previously tested. Four replications of 50 seeds for each treatment were used. The seeds were placed in a gerbox on paper towel and kept for 90 days in an incubator (BOD) adjusted at alternating temperature (20-30ºC) and 12-hour photoperiod. The parameters evaluated were speed of germination and final germination percentage. The remaining seeds were subjected to the tetrazolium test to verify seed viability. The X-ray test was shown to be effective for separating the seeds into categories based on their internal morphology. The radiation of 30Kv for 45 seconds allowed visualization of the internal structures of the seeds. The capitulum maturation stage with seeds without internal papus at the time of dispersion was the best for seed collection.
Descrição
Palavras-chave
semente, análise de imagens, maturação, germinação, planta medicinal, seed, image analysis, maturation, germination, medicinal plant
Como citar
Revista Brasileira de Sementes. Associação Brasileira de Tecnologia de Sementes, v. 31, n. 2, p. 146-154, 2009.