Individual and combined effect of mercury and manganese on phenol and proline content in leaf and stem of mungbean seedlings

Mungbean (Vigna radiata L. Wilczelk cv. Pusa Baisakhi seedlings were raised in individual (0, 1, 10, 100 and 1000 ppm) and combined solutions (1 : 1, 10: 1, 1: 0 ppm Hg : Mn) of mercury and manganese for 6 days. Phenol and proline were found to accumulate in leaves in response to treatment with heavy metals. The magnitude of accumulation correlated with concentration of metals. However, a reverse trend was noticed in stem for phenol. Accumulation of phenol in response to heavy metal treatment was organ specific and occurred at higher rate in plant parts, which faced the stress mostly. However, accumulation of proline helped the plant to survive stress situation. In combined solutions, amelioration of mercurial toxicity by manganese was recorded.