The response of seedlings of two dipterocarp species to nutrient additions and ectomycorrhizal infection

An experiment was conducted to investigate the effect of ectomycorrhizal infection on growth and nutrient uptake, especially of P and K of dipterocarp seedlings.Hopea helferi (Dyer) Blanco andHopea odorata Roxb. seedlings were grown in a sandy loam soil given a basal dressing. Nutrient treatments were unamended soil (NIL), amended soil with the addition of P and K (F), amended soil without P but with K (-P), amended soil without K but with P (-K), amended soil without P or K addition (-PK). Seedlings grown in the amended soil treatments showed foliar symptoms suggestive of calcium deficiency. Ectomycorrhizal infection appeared to improve shoot Ca concentration and relieved the foliar symptoms. Ectomycorrhizal infection inH. odorata plants increased shoot P concentration and increased shoot and total dry weight to the same or greater extent than those of uninfected plants growing on P amended soil.H. helferi showed a positive response to ectomycorrhizal infection in shoot, root and total dry weight in all nutrient treatments but no response to the nutrient treatments themselves.