Cytogenetic Evaluation of Microsporocytes of Setcresea purpurea (Boom) Flower

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Date
2017
Authors
Sifau, M.
Adekoya, K.O.
Oboh, B.O.
Williams, G. O.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Lagos, Nigeria
Abstract
Setcresea purpurea Boom (Wandering Jews) belongs to the family Commelinaceae of the order Commenilales. The family, made up of 38 genera and about 600 species occurs mostly in the tropical and warm regions of the world. Many are popular as garden or house ornamentals. It is a flower-bearing plant yet it is mostly propagated vegetatively due to the formation of sterile pollen grains thereby making pollination impossible. Cytogenetic study was carried out to observe the chromosome behaviour in the microsporocytes during meiosis with the aim of understanding the reasons behind the sterility of the pollen grains. Immature flower buds of Setcresea purpurea were dissected in a petri dish containing tap water. The microsporocytes were squashed using lactic acetic-orcein stain. Most microsporocytes observed from slide contained 12 bivalents. However, a few contained 10 bivalents and one quadrivalent or 8 bivalents and 2 quadrivalents. This shows that 2n = 24 in the microsporocytes. Other irregularities observed included laggards, abnormal disjunction, chromosome bridges and chromosome fragments all at anaphase - I and micronuclei were low ranging from 1 to 3 in the population of S. purpurea studied. The consequence of these irregular chromosomes is their loss and non-inclusion in the daughter nuclei at telophase - I. The loss of these segments would result in loss of genes on them resulting in the unviable microspores at the end of meiosis. These microspores are the pollen grains in which a large number of them (about 90%) have been found to be sterile thereby making the plant to reproduce asexually by stem -tip cuttings.
Description
Keywords
Setcresea purpurea , cytogenetic , quadrivalents , microspores , laggards
Citation
Sifau, M.O., Adekoya, K.O. Oboh, B. O. and Williams, G. O. (2017). Cytogenetic Evaluation of Microsporocytes of Setcresea purpurea (Boom) Flower. UNILAG Journal of Medicine, Science and Technology (UJMST). 5 (2) : 13 - 23.