| Camptotheca acuminata Descne is a native tree of China. Camptothecin (CPT), a monoterpene indole alkaloid in C. acuminata, has high anticancer activities. Several growth indexes, biomass accumulation and allocation, CPT content and yield in C. acuminata seedlings were determined at different planting densities under the greenhouse and field treatments, respectively. The influence of planting density on seedling growth and camptothecin content was investigated. The main conclusions are as follows:1. Planting density significantly affected plant growth and biomass accumulation of C. acuminata seedlings cultivated in the greenhouse or fields. The optimum planting density for seedling growth was 25 plants/m~2. Plant growth was inhibited at high planting densities obviously, so did at very low density.2. Influence of planting density on CPT content was related to the period of treating time. CPT content linearly increased with increasing planting density in the first two samplings; after the third sample collection, CPT content turned steady with increasing planting density.3. The biomass and CPT yield allocation of C. acuminata seedlings was little affected by planting density. Compared with the ratio of underground parts, the ratio of overground parts was much higher (more than 80%).4. For CPT yield per unit area, the optimal planting density was 100 plants/m~2.5. A linear negative relationship between nitrogen (N) concentration and CPT content and a positive relationship between phosphorus (P) concentration and CPT content were displayed in mature leaves in field cultivation experiments. However, CPT content was little corresponded to the variation of N, P concentrations. In addition, a little effect on chloroplastic pigments in C. acuminata seedlings was showed in our study. |
