Abstract

Salinity of soil is a serious problem affecting plant growth and is increasing steadily in many parts of the world, particularly in arid and semi-arid areas. Arbuscular mycorrhiza (A M) is the most wide spread and significant mutualistic fungi having universal in their association including plants of agricultural and medicinal importance. A. mycorrhiza fungi have been shown to promote plant growth and salinity tolerance by various mechanisms.The effects of inoculation with two A. mycorrhizal fungi Glomus mosseae and Glomusintraradices have been investigated on B. monneiri, an important medicinal plant grown with five different levels of salinity (0.40, 80, 120 and 160 mM). Root colonization, leaf chlorophyll content and tolerance of the plants to salinity were determined. The results indicated that the A. mycorrhizal fungi could infect and colonize the roots effectively under high salinity levels and increased chlorophyll content. Dry mass production was significantly enhanced in the inoculated plants and the effect was more evident at the high salinity levels. More over, A. mycorrhizal colonization has increased Na⁺ and Cl^- uptakeand reduced rhizosphere NaCl level significantly. A. mycorrhizal association significantly increased tolerance of plants to salinity and was found as an effective measure to enhance establishment of the plant and to decrease soil salinity.

Key words: Arbuscular mycorrhiza, Glomus mosseae, Glomus intraradices, Bacopa monneiri, salt tolerance, proline.