INFLUENCE OF DIFFERENT INOCULUM PLACES OF THE MYCORRHIZAL FUNGUS GLOMUS-MOSSEAE ON MYCORRHIZAL COLONIZATION IN GRAPEVINE ROOTSTOCKS (VITIS SP.)

Grapevine rootstocks (Vitis berlandieri x Vitis riparia, cv. SO 4) wer e grown in pots with sterilised soil with low P level from a nursery t o test the effect of a local supply of inoculum of an arbuscular mycor rhizal fungus (Glomus mosseae [Nicol. et Gerd.] Gerdemann et Trappe) o n mycorrhizal colonization of the root system. The inoculum was placed in a 9-cm deep band either in 9-18 cm or in 36-45 cm soil depths. Aft er 6 weeks of growth, mycorrhizal colonisation of roots was highest in the inoculated soil zone. With increasing distance from the inoculum band, mycorrhizal colonization decreased or was absent. When the inocu lum was placed in the top soil, the shoot dry weight and the leaf blad e Zn and P concentrations significantly increased in mycorrhizal as co mpared to nonmycorrhizal plants. When the inoculum was placed in 36-45 cm soil depth, leaf blade Zn and Cu concentrations increased in mycor rhizal plants, but shoot dry weight was not affected. In conclusion, a locally restricted mycorrhizal colonization of the root system was su fficient to increase growth and nutrient uptake of grape rootstocks.