Efficiency Of Inoculation With Arbuscular Mycorrhizal Fungi To Camptotheca Acuminata Seedlings

Camptotheca acuminata, a tree species native to China, has gained great attention for its secondary metabolites camptothecin (CPT) which has remarkable anticancer activities. The effects of inoculation with arbuscular mycorrhizal fungi (AMF) on the growth of C. acuminata seedlings, absorption of nitrogen and phosphorus, photosynthetic characteristic and CPT metabolism in,seedlings were systemic analyzed in greenhouse pots. The main results are as follows.1. The seedlings growth was affected obviously by the AMFs. The height, diameter of stem, root/shoot ratio, water content of leaf and biomass of most arbuscular mycorrhizal seedlings was preferential to non-mycorrhizal seedlings. Especially the seedlings of Am, Ss and Gd which were respective inoculated with Acaulospora mellea, Sclerocystis sinuosa and Glomus diaphanum, were prominent. Their whole biomass was 1.6, 1.4 and 1.3 times of control, respectively. And the allocation of biomass was also affected by mycorrhizal formation. Compared with non-mycorrhizal seedlings, the allocation of biomass in most mycorrhizal roots was significantly increased, but reduced in stem and leaves. The results of co-cultivation times showed that the seedlings growth was usually affected by the four fungi including G. manihot (Gm), A. mellea, S. sinuosa and G. diaphanum after co-cultivated 60 days. About the allocation of biomass, the seedlings of co-cultivated more 40-days Gm and Am more affected seedlings roots growth, and the allocation of its roots biomass was increased, but Gd and Ss were not.2. From the effects on the absorption of nitrogen and phosphorus in seedlings, the arbuscular mycorrhizal formation has less effect on the absorption of nitrogen, but remarkably increased the absorption of phosphorus, especially in the roots. The phosphorus content in Gm, Ss, Gv (seedlings inoculated with G versiforme), Am, Al (seedlings inoculated with A. laevis), and Gd was 3.2-, 3.2-, 3.1-, 3.0-, 2.5-, and 2.2- folds of non-mycorrhizal seedlings, respectively. Compared to the non-mycorrhizal seedlings, the allocation proportion of nitrogen and phosphorus was increased in the roots and reduced in the stems and leaves in the arbuscular mycorrhizal seedlings. According to the results of co-cultivation times, the phosphorus content in excessive 40-days arbuscular mycorrhizal seedlings was obviously higher than the non-mycorrhizal seedlings except the Gm, moreover, the phosphorus content was higher after co-cultivated 80~100 days, and significantly higher than 20 days. On the allocation of nitrogen and phosphorus in the organic, the allocation of phosphorus was significantly affected by the four fungi. The allocation proportion of phosphorus showed the increased trends along with co-cultivated times. However, the co-cultivated times that the allocation proportion of phosphorus reached the maximum is also related to the fungal species.3. Match the influence of mycorrhizal fungi to photosynthetic characteristic of seedlings, in leaves, the contents of chlorophyll a, total chlorophyll, carotenoid, total soluble protein and the net photosynthetic rate (sun light intensity) of most arbuscular mycorrhizal seedlings were entirely higher than non-mycorrhizal seedlings. The influence of the mycorrhiza fungi on the chlorophyll fluorescence parameter was represented by the decrease of origin fluorescence (Fo) and the increase of maximum fluorescence (Fm). Compared with non-mycorrhizal seedlings, the Maximum quantum efficiency of PS II photochemistry (Fv/Fm), Quantum efficiency of PSII (OPS II)" and Photochemical quenching co-efficient (qP) was enhanced, whereas, Non-photochemical quenching co-efficient (NPQ) was lower than non-mycorrhizal seedlings. The results of co-cultivation times showed that the contents of leaf photosynthetic pigment and total soluble protein had a taller value, when seedlings was commonly affected by the four fungi after co-cultivated 60 days, and the net photosynthetic rate was as well as them here. The influence of most mycorrhizal fungi on the chlorophyll fluorescence parameter of seedlings was obvious after co-cultivated 60-100 days.4. The CPT content of most arbuscular mycorrhizal seedlings was higher than non-mycorrhizal seedlings. The CPT content of seedlings was enhanced by Gd, Am, Al and Ss, moreover, the influence of mycorrhizal fungi formation on seedlings roots was more significant than leaves and stems. Compared with non-mycorrhizal seedlings, the allocation of CPT was increased in the roots of most arbuscular mycorrhizal seedlings, whereas, in leaves and stems was reduced. According to the results of co-cultivation times, the metabolism of CPT was influenced by four fungi, generally, the CPT content of Gd, Am and Ss was higher after co-cultivated 40~80 days, and mainly in the roots. The allocation of CPT in the organics was increased in Gm, Gd and Am mycorrhizal roots and decreased in the leaves, but the Ss was different. The allocation of CPT in the roots was larger after co-cultivation 40~60 days, and then, the proportion was reduced slightly, but it still higher than non-mycorrhizal seedlings.On the other hand, either single inoculation or co-cultivated times experiment, the AMF have obvious various between species and genus on the growth of seedlings, the absorption of nitrogen and phosphorus, photosynthetic characteristic and CPT metabolism in seedlings, moreover, the relationship between the species and the genus was not distinctness from our study.