THE EFFECTS OF INOCULATION OF MYCORRHIZAL FUNGI ON PHOSPHORUS NUTRITION AND GROWTH OF CITRUS SEEDLINGS
Tang Zhen-yao (Institute of Citrus, Chinese Academy of Agricultural Science) Wan Zhao-liang (Department of Soil Chemistry, Southeast Agricultural College)
Two mycorrhizal fungi CC-1, CC-2 were used to inoculate the roots of three citrus species. Anatomic investigation showed that they might be associated with the host plant to form endomycorrhiza, but there were significant differences in the degree of infection among different citrus species.At the time of four and a half months after inoculation, the rate of infection of glorious orange inoculated with CC-1 and it was found that there were mycelia on the root surface and plenty of vesicles and arbuscules in cortex. The infection rate of rough lemon inoculated with CC-2 was 70%, and there was no mycelium on the root surface, and the infection rate of Poncinus trifoliata was the minimal.Experiment with phosphorus fertilizer labelled by radioisotope ~(32)p showed that mycorrhiza enhanced citrus seedlings to absorb more phosphorus either from fertilizer or from soil, therefore the total phosphorus content and phosphorus level per unit dry matter of inoculated seedling were significantly higher than those of the control. It was also found that the fresh weight, length of shoots and leaves and diameter of trunk ofinoculated citrus seedlings were greater than those of the control.