Mycorrhizal inoculant alleviates salt stress in Sesbania aegyptiaca and Sesbania grandiflora under field conditions: evidence for reduced sodium and improved magnesium uptake.
A field experiment was conducted to examine the effect of the arbuscular mycorrhizal fungus Glomus macrocarpum and salinity on growth of Sesbania aegyptiaca and S. grandiflora. In the salt-stressed soil, mycorrhizal root colonisation and sporulation was significantly higher in AM-inoculated than in uninoculated plants. Mycorrhizal seedlings had significantly higher root and shoot dry biomass production than non-mycorrhizal seedlings grown in saline soil. The content of chlorophyll was greater in the leaves of mycorrhiza-inoculated as compared to uninoculated seedlings. The number of nodules was significantly higher in mycorrhizal than non-mycorrhizal plants. Mycorrhizal seedling tissue had significantly increased concentrations of P, N and Mg but lower Na concentration than non-mycorrhizal seedlings. Under salinity stress conditions both Sesbania sp. showed a high degree of dependence on mycorrhizae, increasing with the age of the plants. The reduction in Na uptake together with a concomitant increase in P, N and Mg absorption and high chlorophyll content in mycorrhizal plants may be important salt-alleviating mechanisms for plants growing in saline soil.
Giri
Bhoopander
B
Department of Botany, University of Delhi, 110007 Delhi, India. bhoopg@yahoo.com
Mukerji
K G
KG
D002734:Chlorophyll / Q000378:metabolism; D007887:Fabaceae / Q000378:metabolism / Q000382:microbiology*; D005658:Fungi / Q000378:metabolism* / Q000502:physiology; D008274:Magnesium / Q000378:metabolism*; D038821:Mycorrhizae / Q000378:metabolism* / Q000502:physiology; D036226:Seedlings / Q000378:metabolism / Q000382:microbiology; D012964:Sodium / Q000378:metabolism*; D012987:Soil
D012987:Soil; D002734:Chlorophyll; D012964:Sodium; D008274:Magnesium