Resumo
The occurrence of polyembryonic seeds in Mangifera indica has been known for a long time, but nothing is known with reference to the forms cultivated in Brazil. It was found impossible to count the number of embryos in the seed, in spite of the size of both seed and embryo. But the cotyledons are in such a way twisted around each other that it is impossible to separate them. Thus it was necessary to take into acount only the embryos which were able to germinate and their number was determined after 3 and 7 months. It was necessary to dig up the seedlings and wash off all soil in order to distinguish ramifications of shoot and root from the actual polyembryony. In 7 months old seedlings a new complication arises owing to the complete fusion of their base. Evidently there is a pronounced variation in the occurrence of polyembryonic seeds. In 30 resp. 40 germinated seeds, taken from one tree each oí the varieties "Santa Alexandrina" and "Itamaracá", all had one embryo only, while in "Pêssego" (one tree), "J. F. da Silva" (two trees) and "Oliveira Neto" (one tree) from 46 to 84% of the seeds contained more than one embryo. "Oliveira Neto", with 24 polyembryonic seeds out of the 25 germinated, had 4 seeds with four embryos and 1 with five.
Poliembri onia em mangueira mangifera indica, L
F. G. Brieger (* (* ) Da Escola Superior de Agricultura "Luiz de Queiroz". ); J. T. A. Gurgel (* (* ) Da Escola Superior de Agricultura "Luiz de Queiroz". )
SUMMARY
The occurrence of polyembryonic seeds in Mangifera indica has been known for a long time, but nothing is known with reference to the forms cultivated in Brazil.
It was found impossible to count the number of embryos in the seed, in spite of the size of both seed and embryo. But the cotyledons are in such a way twisted around each other that it is impossible to separate them.
Thus it was necessary to take into acount only the embryos which were able to germinate and their number was determined after 3 and 7 months. It was necessary to dig up the seedlings and wash off all soil in order to distinguish ramifications of shoot and root from the actual polyembryony. In 7 months old seedlings a new complication arises owing to the complete fusion of their base.
Evidently there is a pronounced variation in the occurrence of polyembryonic seeds. In 30 resp. 40 germinated seeds, taken from one tree each oí the varieties "Santa Alexandrina" and "Itamaracá", all had one embryo only, while in "Pêssego" (one tree), "J. F. da Silva" (two trees) and "Oliveira Neto" (one tree) from 46 to 84% of the seeds contained more than one embryo. "Oliveira Neto", with 24 polyembryonic seeds out of the 25 germinated, had 4 seeds with four embryos and 1 with five.
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LITERATURA CITADA
- 1. Braun, A. Ueber Polyembryonie und Keimung von Caelebogyne. Abh. Ak. Berlin, phys. KI. 1859: 107-263, 1860.
- 2. Cook, M. T. Notes on the polyembryony. Torreya 7: 113-117. 1907.
- 3. Strasburger, E. Ueber Polyembryonie. Jenaische Zeitschr. 12: 647-670. 1878.
Datas de Publicação
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Publicação nesta coleção
29 Jun 2010 -
Data do Fascículo
Dez 1942
