Tree Genetics and Molecular Breeding 2025, Vol.15, No.3, 89-97 http://genbreedpublisher.com/index.php/tgmb 90 PRR7, GI, GID1B, GID1C related to flower induction, and LFY, PNF, PNY, etc. related to flower bud formation (Liu et al., 2020a). There are also some key genes, such as SOC1, HD3A and LFY, which play major roles throughout the flower formation process (Xu et al., 2022). Furthermore, transcriptome analysis also revealed that the expression levels of some transcription factors, such as WRKY, ERF, bHLH, MYB and MADS-box, would increase during flowering period changes, indicating that they are important for flowering period regulation (Liu et al., 2017). 2.2 Seasonal and developmental cues influencing flowering The flowering of tea plants is jointly influenced by seasonal factors (such as light duration and temperature) and the plant’s own hormones. Studies have found that during the development of tea plant flowers, many genes are related to the biological clock and the autonomous flowering pathway. Hormone levels also change significantly during the flowering period. For example, the contents of auxin and gibberellin fluctuate up and down, and the related synthesis and signaling pathway genes also change accordingly (Xu et al., 2022). Some specific genes, such as CsFLC1 (a member of the MADS-box family), have high expression levels during winter dormancy and flowering periods and may be involved in regulating seasonal flowering (Liu et al., 2022). Furthermore, miR156 controls the flowering time by influencing SPL-like genes (such as CsSPL1), and the higher the expression of miR156, the later the flowering time. The genes of the PMEI family (such as CsPMEI2 and CsPMEI4) can also accelerate the flowering process, and they function through the autonomous flowering pathway (Wang et al., 2022). 2.3 Anatomical and morphological features of tea flowering Tea plants have bisexual flowers, which means that the same flower contains both stamens and pistils. The structure of flowers is the same as that of general angiosperms, including sepals, petals, stamens and pistils. During the development of floral organs, many secondary metabolites accumulate, such as flavonoids and anthocyanins. These substances are mainly concentrated in the petals and stamens (Chen et al., 2018). During pollen development, the content changes of certain flavonols (such as derivatives of kaempferol) are highly related to the viability of pollen (Shi et al., 2021). When tea plants flower, nitrogen and sugars in the leaves are redistributed and transported to the flowers, which need these substances to complete development (Fan et al., 2019). In addition, the formation of flowers is also closely related to ethylene, other hormone signals, and the regulation of certain transcription factors (Liu et al., 2020b). 3 Environmental and Hormonal Control of Flowering Time 3.1 Influence of photoperiod and temperature The flowering time of tea plants is influenced by environmental factors such as the duration of light (photoperiod) and temperature. Research has found that many genes controlling flowering are related to circadian rhythms and autonomous flowering pathways. Among them, the SOC1 gene plays a very crucial role in the development process of flowers (Xu et al., 2022). There are also FLC genes like CsFLC1, which have high expression levels during plant dormancy and flowering in winter. This suggests that it may be the key for plants to sense low temperature and control flowering time (Liu et al., 2022). Environmental signals affect proteins like FT through photosensitive proteins and biological clocks. FT moves to the top of plants and initiates flowering (Freytes et al., 2021). Temperature changes and vernalization processes can also regulate these signals, thereby making the flowering time more adaptable to seasonal changes (Lee et al., 2023). 3.2 Roles of phytohormones During the flowering process of tea plants, the content of hormones in their bodies and the expression of genes related to hormones will also change. Studies have found that more than 200 genes related to hormone synthesis and nearly 200 genes related to hormone signal transduction are involved during flower development (Xu et al., 2022). Hormones, such as gibberellin (GA), abolic acid (ABA), ethylene and auxin (IAA), can affect flower formation by regulating key genes such as SOC1, FT and LFY (Liu et al., 2017; Liu et al., 2022). The use of exogenous hormones can also affect flowering. For example, spraying ethephon can cause some flowers and flower buds to drop and regulate the expression of the ethylene receptor gene CsETR (Zhang et al., 2022). In
RkJQdWJsaXNoZXIy MjQ4ODYzNA==