In vitro effect of chromium, lead and manganese on seed germination, growth and mineral composition of finger millet (Eleusine coracana)

It is a well-known fact that heavy metal stress is one of the serious threats to agricultural yield. In the present work, heavy metal screening was carried out using chromium (Cr), lead (Pb) and manganese (Mn) independently on finger millet [Eleusine coracana (L.) Gaertn.] seed and seedling growth under in vitro conditions. Adverse effects of chromium on finger millet seed germination as well as seedling architectural damage were noticed from 10 ppm onwards. Particularly, 30 and 15 % of seed germination was noticed at 50 and 100 ppm concentrations of chromium, respectively. But the extremely toxic lead did not prove its toxic nature when compared to chromium and even at 100 ppm concentration the reduction of seed germination and seedling growth were minor. Manganese promoted the seed germination even at 50 and 100 ppm concentrations. In ICP-OES (inductively coupled plasma-optical emission spectrometer) analysis, contents of residual nitrogen, phosphorous, potassium and sulphur were reduced in seedlings grown on media containing high concentrations of chromium which indicated the toxic levels of this particular metal in this crop. In addition, the sulphur content slightly increased in seedlings treated with higher concentration of lead and showed almost double amount in seedlings treated with high concentration of manganese. The contents of microelements varied with different treatments and as expected content of managense increased in seedlings treated with high concentration of manganese.