Effects of lead and simulated acid rain on chlorophyll contents of selected tropical mosses

Abstract

The effects of lead and acid rain on chlorophyll accumulations were investigated in Archidium ohioense, Bryum coronatum and Octoblepharum albidum. Four regimes of moss colonies were treated with simulated acid rain using dilute H₂S0₄ (pH=5), lead using 1.0 ppm Pb(N0₃)₂ solution, interaction of lead and acid and control regime (treated with only distilled water). Sampling commenced a day after application of each solution at a rate of 1.0 ml per cm² of moss coverage. Chlorophylls a and b contents of moss samples were analysed weekly using standard methods. The levels of acid and lead concentration used did not have negative effect on chlorophyll contents in the three mosses. Low chlorophyll a/b ratio was observed in Octoblepharum albidum. However, high accumulation of chlorophyll in O albidum may be due primarily to the presence of chlorocysts (tissue with abundant chlorophylls). However, lead and lead acid interaction treatments enhanced accumulation of the chlorophylls a,b as well as chlorophyll a/b ratios better than the control in all the three mosses. The study concluded that the selected mosses can be bio accumulators of this heavy metal it is not all levels of heavy metals.

Keywords: Acid Rain, Mosses, Chlorophyll, Lead, Contents