The Effect of Rhizophagus Tenuis Mycorrhizas on Ryegrass, Cocksfoot and Sweet Vernal

SUMMARY Growth of ryegrass ( Lolium perenne ) in a soil extremely deficient in available phosphorus, depended on conversion of most of the root system into endomycorrhizas by Rhizophagus tenuis. A further growth increment could be obtained in infected plants by adding other nutrients, whereas uninfected plants responded only to phosphorus. Cocksfoot ( Dactylis glomerata ) and sweet vernal ( Anthoxanthum odoratum ) also relieved extreme phosphorus deficiency by symbiosis with Rhizophagus tenuis ; but in slightly more fertile soil all three grasses grew better without the fungus. Then R. tenuis grew mainly in the rhizosphere of inoculated plants with much less penetration.