MYCORRHIZAL DEVELOPMENT IN EUCALYPTUS CAMALDULENSIS DEHNH

Effects of arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) inoculation on mycorrhiza formation and development in E. camaldulensis seedlings were assessed in this study. Two experiments, the first with AM fungi and the second with EM fungi, were set up successively using vermiculite-peat (VP) as growth medium, and 2.5 mg l-1, 5.0 mg l-1, 10 mg l-1 and 20 mg l-1 phosphorus (P) Ingestad's nutrient solution in each experiment. The AM experiment using three AM inocula (including Glomus clarum Nicolson and Schenck. (isolate BR148-1) and Gigaspora rosea Nicolson and Schenck. (isolate FL105-5) and one from a trap culture of Bangladeshi soil) resulted in 30-50% colonisation; most colonisation was by G. clarum BR148-1 and was the highest at 10 mg l-1 P (>50%). In a similar experiment using five isolates of Pisolithus tinctorius (Pers.) Coker and Couch., only isolate K55 resulted in colonisation >15% most of which occurred at 2.5 mg l-1 P (>25%) while the other isolates resulted in <1% colonisation. This study showed that E. camaldulensis tended to be colonised more readily by arbuscular- than ecto-mycorrhizal fungi in the initial period of seedling growth. There were indications that the species could become ectomycorrhizal after 16 weeks of growth in glasshouse, but that proper care should be taken to select appropriate and compatible EM inoculants.