Occurrence of 2n and jumbo pollen in the Brazilian ginseng (Pfaffia glomerata and P. tuberosa) |
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Authors: | Onildes Maria Taschetto Maria Suely Pagliarini |
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Institution: | (1) Department of Biology, State University of Western Paraná (UNIOESTE), 85.814-110 Cascavel PR, Brazil;(2) Department of Cell Biology and Genetics, State University of Maringá, 87.020-900 Maringá PR, Brazil |
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Abstract: | An analysis of microsporogenesis was carried out in four populations of Pfaffia tuberosa (2n=4x=68) and in ten populations of P. glomerata(2n=2x=34). Monads, dyads and triads were reported at high frequency in all populations of P. tuberosa. In P. glomerata, on the other hand, only four populations presented monads, and at low frequency. Dyads and triads were observed in both
species, albeit at a higher frequency in P. tuberosa populations. Certain abnormalities of spindles in the second division, such as sequential and tripolar spindles, led to triad
formation by the rejoining of two chromosome sets. The precise causes of monad and dyad formation have not been found during
meiosis, although evidence exists that dyads originated by omission of second meiosis and monads by omission of both meiotic
divisions.
This revised version was published online in July 2006 with corrections to the Cover Date. |
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Keywords: | 2n gametes jumbo pollen meiosis Pfaffia glomerata P tuberosa polyploidy |
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