MORPHOLOGICAL CHARACTERISTICS OF LOQUAT MYCORRHIZA AND INOCULATION EFFECTS OF ARBUSCULAR MYCORRHIZAL FUNGI ON LOQUAT

The structures of arbuscular mycorrhizal fungi (AMF), including arbuscles, vesicles, intraradical and extraradical hyphae, were observed in cortex of the fibrous roots Of field-grown loquat plants (Eriobotrya japonica Lindl.). AMF spores were isolated from rhizosphere with wet-decanting method. Enumeration of spores in soils from 7 sampling sites indicated that, in spring, the spore densities in soils from the southern sites were significantly higher than that from the northern sites, e.g. Jiangsu and Zhejiang. In another experiment, ‘Jiefangzhon’ loquat seed were sown in non-sterilized substrate in pots at greenhouse conditions. Three exogenous AMF isolates, Acaulospora leavis, Glomus caledonium and Glomus mosseae, were inoculated around seeds at the ratio of 6% (w/w). Seedlings were harvested after growth of 11 months. Results showed that 3 introduced isolates and the indigenous AMF colonized the fibrous roots. Inoculation with exogenous AMF increased the infection rate by 11.5 to 18.4%, compared with the control colonized by only the indigenous AMF. The inoculation effect of A. leavis was better than others. The seedling height, stem diameter, shoot fresh weight, shoot dry weight, root fresh weight and root dry weight were 53.7 cm, 0.87 cm, 126 g, 37.7 g, 23.2 g and 7.2 g, respectively, and increased by 5.9%, 10.1%, 22.1%, 19.5%, 65.2% and 96.7% respectively as compared with the control. Although the inoculation with exogenous AMF did not significantly increase the biomasses of seedlings, A. leavis significantly elevated the root/shoot ratio while G. caledonium significantly decreased it. Nutrient analysis revealed that G. mosseae significantly increased N and P contents in shoots, but decreased K content in shoots and P and K contents in roots. G. caledonium significantly decreased K content in shoots and P and K contents in roots. A. leavis significantly increased N content and decreased K content in roots, but did not influence K content in shoots.