The most common heavy metal pollutant in the environment is lead (Pb). Pb is not essential element, but they absorb it when it is present in their environment, particularly in rural areas where the soil is contaminated by automobile exhaust and fields contaminated with fertilizers containing heavy metal impurities. To investigate lead effects on growth parameters, phytoextraction parameters and some stress modulators, Carica papia was grown under normal conditions and stressed with Pb(NO3)2 at three concentrations (0, 200, 400 and 800 ppm). The investigation showed that lead is accumulated in papia plant, which reduced growth and lower photosynthesis pigments. The phytoextraction parameters were also affected by lead. A significant drop in contents of chlorophylls a and b, as well as proline and POD, is associated with the deficit. This work was to evaluate changes in growth and some physiological parameters of Carica papaya under different lead treatments.
Key words: papaya, lead, protein, pigments