Significance of endomycorrhizas in tussock grassland in Otago, New Zealand

Abstract

Endomycorrhizas and Endogone spores are ubiquitous in Otago tussock grassland. Typical Endogone endophytes predominate. but Rhizophagus tenuis is common in high-altitude grasses, and predominates in transplants brought to low altitude.

Glasshouse and field experiments indicate that only at higher altitudes in Otago tussock grasslands is the phosphorus available in soil in the range (<8 ppm Truog test) where grasses are likely to be mycotrophic. Of the five tussock grasses investigated (Festuca novae-zelandiae, Poa laevis, P. colensoi, Chionochloa rigida. C. macra). only two—Chionochloa rigida and Poa colensoi—seem likely to benefit from endomycorrhizal infection in their natural soils.