Evaluation of Atrichum undulatum as an effective indicator of lead pollution in soil

Abstract

Aim: The aim of this study was to evaluate the sensitivity of Atrichum undulatum to soil Pb contamination and check its affectivity as an indicator of Pb pollution indicator. Methodology: Soil and plant samples were collected and characterized. Plants were grown in different levels of Pb contaminated soil (35, 70,140 and 280 mg kg-1, respectively). After 35 days, the plant samples were cut and ground to determine physiological and biochemical parameters. Results: Soil available Pb accounted for approximately 15–24% of total Pb, and the ratio of available Pb decreased with increase in treatment concentration. All the above mentioned parameters were closely related to soil Pb stress, especially when soil Pb concentration was higher than 140 mg kg-1. A. undulatum had a low tolerance to Pb and distinct responses to soil Pb pollution, with visible symptoms such as damaged sporophytes and gametophytes. When soil Pb concentration was in low concentration (70 and 140 mg kg-1), the leaves turned yellow and brown. When soil Pb concentration increased to 280 mg kg-1, the seta softened and kinked and eventually, the plants withered and died. Interpretation: Changes in physiological and biochemical parameters of tested plants such as chlorophyll, soluble protein and MDA content were related to soil Pb stress, especially to soil bioavailable Pb content, and corresponded well to changes in soil Pb pollution level. The results suggest that A. undulatum can be used as indicators to monitor and evaluate Pb pollution in soil.