Source Year: 2002

A greenhouse experiment was conducted to investigate the effects of vesicular arbuscular mycorrhizas (MVA) and different phosphorus rates on the growth of rubber (Hevea brasiliensis) seedlings. Treatments were three levels of P application (0.9, 1.8 and 2.7 g P2O5 per seedling), as triple superphosphate and two mycorrhizal inoculation (non-inoculated and inoculated with Gigaspora margarita), both in a sterilized soil. The parameters analysed were root infection, plant height and diameter, shoot dry weight, concentration and absorption of N, P, K, Ca, Mg, S, B, Fe, Mn and Zn in the shoots. Plants were harvested nine months after planting of rubber seedlings. Phosphorus rates increased root infection, plant growth in height and diameter, and dry weight of shoots. Phosphorus rates also increassed the concentrations of P, S, B and decreased the concentration of K in the leaf. The highest P rates increased the absorption of N, P, Ca, Mg, S, B and Fe but did not influence the absorption of K, Mn and Zn by the plant. The root analysis did not show the presence of inoculated MVA fungus G. margarita. However, there was evidence of infection caused by Rhizoctonia spp., which was correlated with higher plant growth at the highest p level. The B supply in the soil, at a concentration of 1mg/kg, induced plant toxicity.