External and internal p requirements of plant species differing in their mycorrhizal dependency

Abstract

Species of plants distinctly differing in their dependence on vesicular‐arbuscular mycorrhizal (VAM) symbiosis were grown in potted soil at soil solution P levels ranging from 0.003 to 0.6 mg L^‐1. Vesicular‐arbuscular mycorrhizal colonization levels generally decreased with increase in soil solution P concentrations, the degree of decrease being more pronounced with decrease in VAM dependency of host species. Mycorrhizal inoculation effect (MIE) disappeared at a much lower soil solution P concentration in the marginally to moderately VAM dependent Sesbania species compared to MIE noted in Leucaena leucocephala, a very highly VAM‐dependent species. Under nonmycorrhizal condition, the former species exhibited lower external and higher internal P requirement for dry matter production compared to the latter species.

Key words:

• Brassica nigra
• Glomus aggregatum
• Leucaena leucocephala
• Leucaena retusa
• pinnule P concentration
• Sesbania grandiflora
• Sesbania pachycarpa
• soil solution P
• VAM dependency