Ploidy response of B chromosome in root meristem of butea monosperma.

The experiment was set up to resolve the controversy about uniform retention of B chromosomes at various ploidy levels. This paper presents the ploidy response of B chromosome in root meristem of Butea monosperma-a tree, growing around Lucknow. The root tips had euchromatic distinguishable 1B chromosome which showed different behaviour at different ploidy levels. On treatment with 0.2% aqueous colchicine different levels of ploidy were observed. Tetraploids and mixoploids showed 2B chromosomes instead of 1B chromosome as in diploid i.e. B chromosome divides along with A chromosome showing behaviour similar to A chromosome. But in few tetraploids, mixoploid cells and one octaploid cell undivided 1B chromosome like diploids was observed.