VESICULAR-ARBUSCULAR MYCORRHIZA IN NATURAL VEGETATION SYSTEMS

III. NUTRIENT TRANSFER BETWEEN PLANTS WITH MYCORRHIZAL INTERCONNECTIONS

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Summary

The functional role of mycorrhizal interconnections between plants was investigated in pot experiments which were designed to simulate some of the circumstances of the regeneration niche in grassland.

Young plants of Festuca ovina L. and Plantago lanceolata L. were grown in pots in close association with adults of the same species in the mycorrhizal (M) and non-mycorrhizal (NM) condition. 32P or nutrient solution was applied to isolated parts of mature ‘source’ plants and transport of the nutrients to younger ‘sink’ plants was examined in the mycorrhizal and non-mycorrhizal condition. Transport was determined either by measuring 32P in, or total yield of, sink plants at sequential harvests.

Greater movement of 32P occurred into roots of mycorrhizal plants of both species. The differences were stastistically significant after only 24 h in F. ovina and after 48 h in P. lanceolata. Application of nutrient solution to source plants led to significantly greater yield in M sinks after 18 and 30 weeks.

It is concluded that direct transfer of nutrients between living source and sink plants occurs by way of connecting mycorrhizal hyphae. The significance of these observations for nutrition and survival of young plants is assessed and the broader implications for nutrient cycling in ecosystems considered.

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