Meiotic arrest compromises pollen fertility in an interspecific hybrid between Brachiaria ruziziensis x Brachiaria decumbens (Poaceae: paniceae)

Brazilian Archives of Biology and Technology

Andréa Beatriz Mendes-bonato²  Maria Suely Pagliarini¹  Cacilda Borges Do Valle¹ 

[1] ,State University of Maringá Department of Cell Biology and Genetics Maringá PR ,Brasil

关键词: Brachiaria decumbens;    Brachiaria ruziziensis;    cell fusion;    interspecific hybrid;    meiosis arrest;    pollen sterilitiy;   

DOI  :  10.1590/S1516-89132007000500011

来源: SciELO

【 摘 要 】

Microsporogenesis was analyzed in an interspecific hybrid between an artificially tetraploidized sexual accession of Brachiaria ruziziensis (2n=4x=36) and a natural apomictic tetraploid accession of B. decumbens. Syncytes involving a large number of cells were recorded in 15.4% of meiocytes. Meiosis progressed normally in syncytes during prophase I; in metaphase I, however, several nuclei were found fusioned, showing chromosome stickiness and several chromosome fragments. Meiosis was arrested in metaphase I and pycnotic nuclei and micronuclei were formed. Abnormal cytokinesis fractionated the syncyte into abnormal meiotic products that were covered by the pollen wall. Meiocytes in leptotene were recorded in all the slides prepared for both meiotic divisions, and abnormal "pollen grains" with well-developed pollen wall but containing leptotene nuclei were recorded in 9.18% of grains analyzed. These findings suggested that the meiocytes received the signal to enter meiosis but lacked the signal to proceed beyond leptotene. Despite the absence of the meiotic process, such cells were covered by pollen grain wall. Total pollen sterility resulted from these abnormalities combined with still others observed among meiocytes.

【 授权许可】

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