Abstract:
The activities of Cu2+ and Zn2+ on Barbula lambarenensis were examined to understand the extent of metal damage to the chlorophyll content. The moss was exposed to high concentrations between 0.01 M−1 M of the metal ions in one case, and in the other case, varied doses of citric acid and acetic acid were introduced to each of the metal ion solution. The pH of the metal solutions was adjusted as necessary before exposure and the effect of contact time was determined at intervals within 24 h. Depletion of chlorophyll a increased with metal concentration and was pH dependent, with Cu2+ recording the highest in a 24 h period. The highest activity was observed at 0.0270 M free Cu2+ and 0.0985 M free Zn2+. The activity of Zn2+ ion in the nitrate and chloride environment was subjected to paired t-test. The mean chlorophyll a degradation (M= -0.009, SD=0.0178, N= 7) was significantly less than zero, t (6) = -1.4, two-tail p=0.21, providing evidence that the activity of the two Zn2+ in the different anionic environment was the same. The IR spectra indicated a direct action of Cu2+ and Zn2+ on chlorophyll. Acetic acid promoted the degradative effect of the metal ions while citric acid seemed to be ineffective on the plant.
