The effects of heavy metals on chromosomal structure and chlorophyll contents in chilli variety ns 1701 dg

Nazarul Hasan and Sana Choudhary Rafiul Amin Laskar

The genome of the Capsicum annum L. is a representative complex plant genome having the chromosome no 2n = 24 and has the largest genome size (3.2 GB) than the other members of solanaceae family. Experiments were carried out to understand the effects of different doses of heavy metals (such as Pb(NO3)2 and Cd(NO3)2) on the chromosomal structure and the chlorophyll contents of chilli plant. On the exposure these chemical mutagens to chilli shows high frequency chromosomal and chlorophyll mutations. Changes in chromosomal structure like micronuclei, univalent, multivalent, stickiness, laggard, bridges, fragmentation and chlorophyll mutants like xantha, dark xantha, albino, viridis, variegate, aurea etc. were observed, respectively. The frequency of chromosomal aberrations was proportional to concentrations of heavy metals and highest at 300PPM and 500PPM for Cd(NO3)2, 400PPM and 500PPM for Pb(NO3)2 respectively. Highest total chlorophyll content was found in chlorina mutant that is about 1.52mg/g and lowest chlorophyll content was reported in xantha i.e. 0.15mg/g. From the experimental studies it was reported that frequencies of chromosomal and chlorophyll mutations were increased with doses of heavy metals and Cd(NO3)2 found again to be more effective in compare to the Pb(NO3)2. Chemical mutagens can be used as additional approaches to get better ideal characters for example characters related to yield.

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