Floral initiation is a major phase change in the spermatophyte, where developmental programs switch from vegetative growth to reproductive growth. It is a key phase of flowering in tea-oil trees that can affect flowering time and yield, but very little is known about the molecular mechanism of floral initiation in tea-oil trees. A 12-year-old Camellia oleifera (cultivar ‘changlin53’) was the source of experimental materials in the current study. Scanning electron microscopy was used to identify the key stage of floral initiation, and transcriptome analysis was used to reveal the transcriptional regulatory network in old leaves involved in floral initiation. We mined 5 DEGs related to energy and 55 DEGs related to plant hormone signal transduction, and we found floral initiation induction required a high level of energy metabolism, and the phytohormones signals in the old leaves regulate floral initiation, which occurred at stage I and II. Twenty-seven rhythm-related DEGs and 107 genes associated with flowering were also identified, and the circadian rhythm interacted with photoperiod pathways to induce floral initiation. Unigene0017292 (PSEUDO-RESPONSE REGULATOR), Unigene0046809 (LATE ELONGATED HYPOCOTYL), Unigene0009932 (GIGANTEA), Unigene0001842 (CONSTANS), and Unigene0084708 (FLOWER LOCUS T) were the key genes in the circadian rhythm-photoperiod regulatory network. In conjunction with morphological observations and transcriptomic analysis, we concluded that the induction of floral initiation by old leaves in C. oleifera ‘changlin53’ mainly occurred during stages I and II, floral initiation was completed during stage III, and rhythm–photoperiod interactions may be the source of the main signals in floral initiation induced by old leaves.

Flowering is a key agronomic trait that directly influences the yield of the tea-oil tree (Camellia oleifera). Floral initiation, which precedes flower bud differentiation, represents a critical developmental stage affecting the flowering outcomes. However, the molecular mechanisms underlying floral initiation in C. oleifera remain poorly understood. In this study, buds from five key developmental stages of a 12-year-old C. oleifera cultivar ‘changlin53’ were collected as experimental samples. Scanning electron microscopy was employed to identify the stage of floral initiation. UPLC-MS/MS was used to analyze endogenous gibberellin (GA) concentrations, while transcriptomic analysis was performed to reveal the underlying transcriptional regulatory network. Six GA types were detected during floral initiation and petal development. GA₄ was exclusively detected at the sprouting stage (BII), while GA₃ was present in all samples but was significantly lower in BII and the flower bud primordium formation stage (BIII) than in the other samples. A total of 64 differentially expressed genes were concurrently enriched in flower development, reproductive shoot system development, and shoot system development. Weighted gene co-expression network analysis (WGCNA) identified eight specific modules significantly associated with different developmental stages. The magenta module, containing Unigene0084708 (CoFT) and Unigene0037067 (CoLEAFY), emerged as a key regulatory module driving floral initiation. Additionally, GA20OX1 and GA2OX8 were identified as candidate genes involved in GA-mediated regulation of floral initiation. Based on morphological and transcriptomic analyses, we conclude that floral initiation of C. oleifera is a continuous regulatory process governed by multiple genes, with the FT-LFY module playing a central role in the transition from apical meristem to floral meristem.

Kadsura coccinea (Lem.) A. C. Smith is a significant tree species of non-timber forest. However, the low germination percentage and lengthy germination time of its seeds pose obstacles to industry development. Aiming at the problem of seed dormancy, this study first determined the seed dormancy period through seed germination test, and then comprehensively evaluated the dormancy characteristics by observing the seed coat structure, measuring endogenous inhibitors, and in vitro embryo culture. The results indicated the dormancy of K. coccinea seeds, and that the germination period was up to 80 days. Its seed coat is composed of exotesta and endotesta. The dense seed coat structure causes water absorption and air permeability obstacles to the seeds and causes mechanical restraint to the development of the embryo. Meanwhile, its seeds have substances that inhibit seed germination, and there are germination inhibitors in distilled water, methanol, petroleum ether, and ethyl acetate extracts of kernels and seed coats. The inhibitory activity of kernel petroleum ether extract was the highest, and the inhibitory activity of seed coat methanol extract was the highest. In addition, the embryo of K. coccinea developed completely and could germinate normally under in vitro conditions. This study has basically proved that the dormancy of K. coccinea seeds is caused by the seed coat (physical dormancy) and endogenous inhibitors (physiological dormancy), which provides a scientific theoretical basis to further explore the method of seed dormancy release of K. coccinea.

Camellia oleifera is a distinctive woody oilseed species endemic to southern China and is considered one of the world’s four major woody oil plants alongside oil palm, olive, and coconut. Its oil is renowned for its high content of unsaturated fatty acids, earning it the title “Oriental Olive Oil.” However, the conventional C. oleifera industry faces challenges such as substantial yield fluctuations and poorly understood regulatory mechanisms of oil metabolism. There is an urgent need to elucidate the synergistic mechanisms between photosynthetic efficiency and metabolic networks at the molecular level during leaf development to establish a theoretical foundation for high-yield, high-quality breeding. In this study, we systematically analyzed the developmental dynamics of new leaves at the spreading, growth, and maturity stages in the high-yield variety ‘Changlin 53’. By integrating morphological and anatomical observations with multi-period transcriptome sequencing, we investigated the key regulatory networks underlying leaf functional maturation. The results showed that as leaves developed, chlorophyll *a* content increased significantly, the expression of photosynthesis-related genes (e.g., chlorophyll *a*-binding protein Lhca1, photosystem II reaction center protein PsbA) was upregulated, photosynthetic capacity was gradually enhanced, and leaf functional maturation was promoted through the regulation of carbon assimilation and energy metabolism pathways. To validate these findings, 12 randomly selected differentially expressed genes (DEGs) were analyzed using qRT-PCR. The expression patterns were highly consistent with the RNA-Seq data. This study reveals, for the first time, the potential synergistic mechanism involving photosynthesis, metabolism, and hormones during leaf development in ‘Changlin 53’, providing a key theoretical basis for selecting and breeding C. oleifera varieties with high light-use efficiency.

Camellia oleifera Abel. is a typical self-incompatible plant, yet its molecular mechanisms have not been comprehensively elucidated, which constitutes the principal cause underlying the relatively low natural fruit set rate in C. oleifera. S-RNase belongs to the RNase T2 gene family and represents a class of glycoproteins specifically expressed in the style with certain “cytotoxicities” capable of degrading ribonucleic acid (RNA) in their own pollen tube cells, thereby inducing programmed cell death in pollen tube cells. To identify pistil S genes participating in the self-incompatibility response of C. oleifera, nine RNase T2 family genes were identified based on transcriptomic and whole-genome sequencing data of the camellia oil tree and designated CoRNS1–CoRNS9. Systematic evolutionary analysis revealed that CoRNS5, CoRNS7, and CoRNS8 exhibit close phylogenetic relationships with S-RNases of the Camelliaceae family, whereas CoRNS6 shows closer affinity with S-RNases of the Solanaceae family. Analysis of promoter cis-acting elements revealed that RNase T2 family genes are regulated by multiple hormones, including abscisic acid, methyl jasmonate, cytokinin, auxin, salicylic acid, and gibberellin, and possess MYB transcription factor-binding sites. Expression analysis revealed that CoRNS6 is expressed exclusively in the ovary; CoRNS5 is expressed at the highest level in the style, followed by lower levels in the petals, anthers, filaments, receptacle, and ovary; CoRNS1 is expressed in all tissues except anthers; and the other genes are expressed across various floral tissues. Ex vitro pollen culture system experiments demonstrated that the CoRNS1 and CoRNS5 recombinant proteins significantly inhibited the elongated growth of autogamous pollen tubes, whereas CoRNS7 significantly reduced the pollen germination rate. Fluorescence labeling revealed that treatment of autogamous pollen tubes with the recombinant proteins CoRNS1, CoRNS5, and CoRNS7 induced microfilament skeleton depolymerization and increased the Ca²⁺ concentration within the pollen tubes. Additionally, treatment with the CoRNS5 recombinant protein increased the reactive oxygen species (ROS) levels in autogamous pollen tubes. These findings suggest that RNase T2 family genes are involved in the self-incompatibility response in C. oleifera, with CoRNS1, CoRNS5, and CoRNS7 playing pivotal roles. Overall, our results not only offer a theoretical foundation for elucidating the regulatory network governing self-incompatibility in C. oleifera, but also furnish valuable genetic resources for future molecular breeding programs targeting improved self-compatibility and increased fruit yield.