Meiotic chromosome behaviour and karyomorphology of Aloe vera (L.) Burm. f.

Abstract

Aloe vera (L.) Burm. f. (the family Aloaceae) indigenous to Africa is an admired medicinal plant used as a folk medicine. Meiotic division was investigated in A. vera with a view to decipher the behavior of chromosomes during prophase I and the subsequent stages of meiosis following acetocarmine squash technique. The various meiotic stages from leptotene to pollen development were studied. Seven bivalents were clearly visible at diplotene, and the chiasma frequency averaged to 1.86 per bivalent and 13.1 per pollen mother cell (PMC). Prophase I stages are difficult to identify due to clumping of chromosome threads. Second nuclear division, however, allows clear distinction of chromosome configuration. Besides clumping, various other types of chromosomal aberrations such as stickiness and fragments at metaphase I, precocious movement of chromosomes, bridges, laggards and unequal separation of chromosomes at anaphase I and unequal separation of chromosomes at telophase II were noted. Karyomorphological study on the other hand, was carried out in anther wall (mitotic) cells of A. vera. Mitotic as well as meiotic studies in the species showed 2n=14 chromosomes including two pairs of sat-chromosomes. The karyotype of the species was adjudged to be typically asymmetric.