The relationship between growth promotion by arbuscular mycorrhizal fungi and root morphology and phosphorus absorption in gramineous and leguminous crops

Abstract

The relationship between growth promotion by arbuscular mycorrhizal fungi and root morphology and phosphorus absorption were examined for upland rice (Oryza saliva L. var. Nori.n mochi 26), wheat (Tnliaim aestivum L. var. Norin 135), sorgo (Sorghum bicolor Moench var. Sweet), barley (Hordeum vulgäre Lj emend. Lam. var. Kashimamugi), finger millet (Eleusine coracana Gaertn. var. GBP-31), kidney bean (Phaseolus vulgaris L. var. Celina), white clover (Trifolium repens L. var. New Zealand white), cowpea ( Vigna sinensis Endl. var. Kintoki), azuki bean ( Vigna angularis var. Chunagon) and soybean ( Glydne max Merr. var. Enrei). The infection rate of arbuscular mycorrhizal fungi in leguminous crops was higher than that in gramineous crops. Growth promotion by arbuscular mycorrhizal fungi inoculation in leguminous crops was more pronounced than in gramineous crops. The lengths of root and root hair in gramineous crops were greater than those in legminous crops. The number of root hairs in gramineous crops was more than that in legminous crops. The gramineous crops have roots which are more advantageous for phosphorus absorption as compared to legminous crops. As a result, gramineous crops grew better even under conditions of low availability of phosphorus in the soil. Probably because the phosphorus absorption ability in the soil with little available phosphorus was greater for the latter crops, the arbuscular mycorrhizal fungi infection rate was higher for the former crops. Therefore, the inoculation of arbuscular mycorrhizal fungi is more beneficial for legminous crops.