Evaluation of the growth modulating effect of the River Chenab sediments on Brassica napus L., Pakistan

Abstract

This research was conducted to assess the effects of river Chenab sediments on growth modulation of a dicotyledonous plant. For this purpose 57 sediment samples collected from 25 selected sites of river Chenab were evaluated by using Brassica napus L. as a model plant. The physiological effects were determined by observing its different parameters. The process of germination was considerably delayed and growth was significantly inhibited by the samples obtained from various polluted sites. More than 80% growth inhibition was exhibited by seedlings of 49 samples. Seedlings of 37 samples showed above 30% weight loss. Relative dry weight (RDW) was decreased more than 50% in seedlings of 46 samples. Seedlings of all samples showed higher water contents (WC) while the seedlings of 39 samples showed higher relative water contents (R WC) as compared to the control. A set of multi-mode in vitro assays were utilized to evaluate the changes in biochemical contents of target plant. Results showed the reduction of phenolics content in seedlings of 49 samples. The seedlings grown in all samples showed higher flavonoids content. Seedlings of 43 samples showed higher chlorophyll "a" content while the Seedlings of 27 samples showed higher chlorophyll "b" content. Seedlings of 41 samples showed total chlorophyll content higher than control. Seedlings of 45 samples showed the higher values of chlorophyll a ratio b as compared to control. Seedlings of 53 samples showed increase in carotenoids content. Seedlings of 52 samples showed increase in MDA content. Seedlings of 50 samples exhibited lower DPPH free radical scavenging potential. Seedlings of 44 samples exhibited decrease in total antioxidant capacity (TAC). Seedlings of 35 samples showed increase in reducing power. Seedlings of 32 samples showed increased total protein content and the remaining seedlings of 25 samples showed reduction in total protein content. Seedlings of 38 samples showed reduction in protease activity. Seedlings of 54 samples showed reduction in peroxidase (POD) activity while the seedlings of all 57 samples showed relative induction in their SOD activity as compared to the control. Overall, it was concluded that seedlings grown in samples of highly polluted urban and industrial sites showed negative effects on morphological, physiological and biochemical activities of target plant as compared to the samples taken from less contaminated, agricultural and rural areas.