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A detailed Karyotypic and meiotic study in three species of Chlorophytum is presented and its significance is discussed in the light of the modern concepts. Chlorophytum elatum R. Br. is tetraploid with 2n=28 chromosomes, C. heynei Baker. and C. laxum Baker. are diploids with 2n=14 or 16 chromosomes, in x=7 and 8 basic number lines and C. elatum shows asymmetrical karyotype while C. heynei and C. laxum show symmetrical karyotypes. Karyomorphological studies reveal some minor differences between the three species, such as absolute chromosomal length and relative length which clearly indicate a common origin and close relationship of these three species. However, populations of Chlorophytum elatum, C. heynei and C. laxum vary slightly in their intraspecific cytomorphological characteristics which may be the basis of ecotypic differentiation. The behaviour of chromosomes during meiosis in all the 3 species is found to be fairly normal. Nevertheless, in C. elatum quadrivalent association of chromosomes, laggards and bridges are of common occurrence. The presence of B-chromosome in C. elatum is recorded for the first time. |
