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The effects of different concentrations of lead salts on a variety of crop plants

An investigation is described that would be suitable for A-level or first year degree Biology or Environmental Science students. Crop plants were grown in different concentrations of lead chloride and lead nitrate. French beans, carrots and Brussels sprouts were all inhibited at concentrations over 0.01 mol dm-3 showing stunted root growth. The difference in overall seedling length of the control compared with 0.01 mol dm-3 lead nitrate for Brussels sprouts was significant at 0.01 level of probability. Dry weight analysis, however, was inconclusive. Root tips of onion seedlings also grown on lead salts were stained with aceto orcein and stages of mitosis were seen only in the control plants. Suggestions for further work include studying cell division and elongation, dry weight analysis over a longer period and using the test to estimate lead pollution in water or soil.