To explore the patterns of essential oil synthesis and the optimal harvesting period of citral-type Camphora officinarum Nees ex Wall (C. officinarum) at different growth stages, three varieties (C1, C2, C3) from the citral-type C. officinarum coppice were taken as research objects. During the leaf growth cycle from February 2022 to January 2023 (12 periods in total), their morphological indicators, biomass, essential oil yield, chemical components, and output were determined. As a natural monoterpenoid widely used in the food additive, pharmaceutical intermediate, and flavor/fragrance industries, citral-related research is of great significance for improving the breeding value of citral-type C. officinarum germplasm resources. The results showed that: (1) The leaf area, total biomass, and leaf-branch ratio of the three varieties all reached the maximum in Period I (late August, full fruit stage), among which the leaf biomass and total biomass of C1 were significantly higher than those of C2 and C3. (2) The essential oil yield based on dry weight of leaves (0.53–2.79%) was significantly higher than that of branches (0.48–0.7%). Citral (geranial and neral) was the main component of the essential oil; the citral contents in C1 and C2 were the highest in Period G (late June, early fruit stage) (78.38% and 71.78%, respectively), while that in C3 peaked in Period F (late May, late flowering stage) (70.46%). (3) The total essential oil yield reached the peak in Period I, with C1 being significantly higher at 20.19 ± 1.88 g/plant than C2 (13.8 ± 0.61 g/plant) and C3 (16.47 ± 0.87 g/plant). Comprehensive analysis indicated that C1 was identified as the top-performing cultivar among citral-type C. officinarum, and July–August was the optimal harvest period. During this period, both essential oil yield and citral content could be balanced to maximize economic benefits.

This study aimed to investigate the inhibitory effects and mechanisms of essential oil and its endophytic fungi of Camphora bodinieri with citral chemotype (CBCC) against Rhizoctonia solani, the causal agent of rice sheath blight. The antifungal activity was assessed by measuring the inhibition rate at various concentrations. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe ultrastructural changes in the pathogen. For the CBCC bodinieri essential oil treatment group, the MIC was 1.0 μL/mL, and the inhibition rate reached 100%, showing a concentration-dependent effect (0.0625–1.0 μL/mL, inhibition rate 29.02–100%). Electron microscopy showed that the essential oil caused severe damage to hyphal cell membranes, cytoplasmic agglutination, and organelle disintegration, whereas the endophytic fungi caused only local shrinkage and partial deformation. Both the CBCC essential oil and the endophytic fungi exhibit antifungal activity. They are promising candidates for the biological control of rice sheath blight and have potential for development as biofungicides.

To investigate the influence of seasonal dynamics on the endophytic fungal community of Camphora bodinieri with citral chemotype, we employed standardized sampling and high-throughput sequencing to analyze the diversity, composition, and structure of endophytic fungi across different seasons. A total of 1825 Amplicon Sequence Variants (ASVs) were obtained, belonging to 12 phyla, 43 classes, 104 orders, 239 families, 449 genera, and 663 species. Among them, 23 ASVs were shared across all four seasons, suggesting the presence of a core fungal community. The number of season-specific ASVs was highest in autumn (730), followed by summer (336), spring (325), and winter (202). The results showed that season significantly affected the Shannon (F_3,9 = 5.927, p = 0.016) and Simpson (F_3,9 = 4.892, p = 0.026) indices, with the diversity and species richness of endophytic fungi being highest in autumn and lowest in winter. Across different tissues, the similarity of endophytic fungal communities between leaves and stems was comparatively higher than that with roots. Furthermore, different fungal taxa exhibited differential distribution patterns along temperature–moisture gradients. This study explored the seasonal diversity of endophytic fungi in C. bodinieri with citral chemotype, providing a theoretical basis for understanding host–endophyte interactions.