Cytogenetics of selected plant species affected by industrial effluents

Abstract

Two plants viz. Colocasia esculenta (L.) Schott and Ipomoea aquatica Forssk. commonly growing in the industrial effluent affected areas were selected to observe the effect of industrial effluents on chromosomal and DNA level. Five different industrial areas such as (i) Powertex Fashion Ltd., Gazipur (ii) Shetu Pesticide Ltd., Savar (iii) Salma Leather Industry, Hazaribagh (iv) Monno Ceramic Industries, Nayarhat, Dhamrai and (v) Acme Laboratories Ltd., Tulivita, Dhamrai were selected for this study. A number of different experiments like physico-chemical parameters, essential elements, heavy metals, conventional and fluorescent karyomorphology and RAPD have been done for comparative study with control. The amount of heavy metals in soil, water and plant samples were higher in all affected areas. Dissolved Oxygen was found bellow the permissible limit in all the affected areas (lowest 0.88 mg/l in Hazaribagh) indicating high amount of organic wastes discharge from tannery. Heavy metal uptake in Colocasia esculenta is much higher than Ipomoea aquatica. The edible portion consumed more heavy metal than root. Diploid chromosome number 2n=28 was found in Colocasia esculenta collected from Gazipur garments, Savar pesticide and Hazaribagh leather area as well as control. However, 2n=38 chromosomes of the same species were observed in the sample plants collected from Monno Ceramic and Acme Laboratory area. The probable reason for increasing chromosome number was either the sample a new cytotype of the species or some irregularities occurred during cell division. On the other hand, 2n = 30 chromosomes were observed in all plant samples of Ipomoea aquatica including control. In case of both the species, the nature of staining of interphase nuclei and prophase chromosomes of the sample plants were different than those of control. The fluorescent karyotypes of both the species showed significant differences among the samples and with control as well. Fluorescent banding (CMA and DAPI) revealed the probable occurrence of deletion and tandem duplication. The different plant samples of both the species had characteristics RAPD fingerprinting. Lacking of some DNA fragments in some sample plants (which presents in the control plants) may correlate to the deletion of chromosomal parts. Similarly some new fragments in the sample plants (which not found in the control) may corresponds with the tandem duplication of the chromosomal part. Therefore, the substances present in the industrial effluents affected on the chromosome and DNA level of Colocasia esculenta and Ipomoea aquatica.