Effect of Mycorrhizal Inoculation on the Growth and Heavy Metal Uptake of Narra (Pterocarpns Indians Willd.J in Mine Waste Soils

Abstract

Mycorrhizal associations have been known to be effective in the amelioration of metal toxicity on the host plants since they significantly modify the response of plants to heavy metals. This study was conducted to determine the effect of mycorrhizal inoculation on the growth and heavy metal uptake of narra (Pterocarpus indicus') grown in mine waste soils. Pterocarpus indicus seeds were germinated and then transplanted in garden and mine waste soils gathered from Antamok and Cebu. Inoculation treatments of uninoculated, MYKOVAM, and Mine VAM were then applied to the soils. Plant hei^^ht was measured once a week through the entire growth period of two months. Other growth parameters, such as dry weight, mycorrhizal infection and nutrient uptake were measured after harvesting the plants. Fifteen-week old harvested narra plants were sent to the Central Analytical Services Laboratory of BIOTECH for phosphorus and heavy metal analysis. Total biomass of mycorrhizal plants was reduced in mine waste soils. The rate of mycorrhizal infection as well as nutrient uptake was significantly increased due to Mine VAM inoculation of plants. High concentrations of copper (Cu) and lead (Pb) were found in plant tissues, but no signs of toxicity were found among the plants. The effect of mycorrhizal inoculation could have immobilized Pb within the stem of narra. The effect of Mine VAM inoculation was significantly greater than MYKOVAM inoculation in the growth and heavy metal uptake of narra grown in mine waste soils.