EFFECTS OF ARBUSCULAR MYCORRHIZAL FUNGI ON THE GROWTH AND ABSORPTION OF NITROGEN AND PHOSPHORUS IN CAMPTOTHECA ACUMINATA SEEDLINGS

Background and Aims Camptotheca acuminata is a special Chinese tree that produces camptothecin (CPT), a monoterpenoid indole alkaloid, which has gained great attention for its remarkable inhibitory activity against tumour cells. Methods After 70_day growth period,seedlings were inoculated with the arbuscular mycorrhizal (AM) fungi, Glomus manihot (Gm), G. versiforme (Gv), G. etunicatum (Ge), G. diaphanum (Gd), Acaulospora mellea (Am) and A. laevis (Al), respectively. Key Results We investigated the effects of six species of AM fungi, belonging to two genera, on the growth, absorption of nitrogen and phosphorus in C. acuminata seedlings grown in the greenhouse. All inoculated seedlings were infected by six AM fungi and formed arbuscular mycorrhiza. The seedling growth and nitrogen and phosphorus absorption were affected by the formation of arbuscular mycorrhiza in C. acuminata. The biomass of mycorrhizal seedlings was significantly higher than that of non_mycorrhizal seedlings. For most mycorrhizal seedlings, the ratio of root to shoot was larger than that of the control. Nitrogen contents in Gm, Gv, Ge and Al were significantly lower than in the control. In contrast, phosphorus contents in plant of all mycorrhizal seedlings were higher than in non_mycorrhizal seedlings. Arbuscular mycorrhizal formation also changed the allocation of nitrogen and phosphorus in different organs of seedlings. Conclusions These patterns suggest that the symbiotic association between C. acuminata roots and AM fungi effectively maintains nutrient homeostasis through changes in physiological properties, including nutrient uptake and allocation.