S. A. Ekwebelam

Abstract

Seedlings of three varieties or carihbean pine (Pinus caribaea var hondurensis (PCH), P. caribaea var. bahamensis (PCB) and P. caribaea var. caribaea (PCC) were grown for 16 weeks in the nursery, and inoculated with Pisolithus tinctorius, Rhizopogon roseolus, Suillus granulatus and 3 unidentified mycorrhizal fungi. M1, M5 and M8. Isolated from mycorrbizal ischolar_mains of caribbean pine (P. caribaea). The results indicated that there were large differences in growth, yield and nutrient contents between the three host varieties following inoculation, but fewer differences between the fungi in their effects on growth and nutrient contents of the host species. Seedlings of PCH were significantly taller than, and superior in dry matter and nutrient contents to, those of either PCB or PCC; PCC was consistently poorest in these parameters Significantly more ectomycorrhizas developed on ischolar_mains of PCB seedling compared with PCH or PCC. Further, as a group the better known mycorrbizal fungi appeared to be superior to the unidentified fungi species in their effects on growth and nutrient contents of host species. The need to inoculate nursery stock with the most beneficial and most effective fungal symbionts is apparent from these results.

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S. A. Ekwebelam

Abstract

Twelve ectomycorrhizal fungi Pisolithus tinctorius, Rhizopogon luteolus, R. roseolus, Suillus granulatus and 8 unidentified species isolated from Caribbean pine) were compared for their effectiveness in stimulating growth and nutrient uptake in glasshouse grown seedlings of Caribbean pine. Differences occurred between the different fungi in their stimulation of growth and nutrient status of host seedlings. Inoculoation with S. granulatus and R. roseolus gave the best stimulation of height growth and P. tinctorious the poorest. Some unidentified fungi appeared superior to the known mycorrhial species as shown by mycorrhizal infection, dry matter production, and the quantity of phosphorus and potassium absorbed. The number of mycorrhizas produced was correlated with the concentration of P, and the total quantity of P and K absorbed.

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