## 4 Discussion  
The fundamental parenchyma of the floral organ or specialized glandular epidermal cells are usually the places plant fragrance is produced [30]. The formation and accumulation of flower scent are influenced by a variety of elements, but mostly depend on genetic effect. However, the release of VOCs from floral organs does not hinge on the volatilization of its components, but on the selective release of these components into the membrane structure of the synthesis zone by specific carriers [31; 32]. The primary floral aroma components in _T. cordata_ and _T. tomentosa_ flowers in this study vary markedly from the VOCs of their inflorescresence essential oils in previous research [17; 18]. The synthesis and emission of VOCs may be affected by different genotypes and stand conditions together. Studies have also found that the main components of floral volatiles vary greatly even among species of proximal origin [12], and that the primary components of flower volatiles are irregular even within the same genus [33]. Moreover, volatile substances frequently undergo dynamic changes throughout flowers' blossom. Variables were found in the quantity and relative content of fragrance compounds in the three species of _Tilia_ at various flowering periods, which coincided with the analysis of volatile components at different flowering stages in other fragrant plants, such as _Hosta_[34], _Polianthes tuberosa_[35], _Prunus mume_[36], and _Osmanthus fragrans_[37]. According to the volatile components, which are controlled by the actions of related biosynthesis within the flowers, reactions like dehydrogenation, deoxygencation, catalysis and degradation are carried out from opening to decay in order to accumulate or generate new compounds to take part in body metabolism [38]. This ultimately results in variations in categories and relative contents of the volatile components released over time. The emissions of major aroma components in the three species of _Tilia_ were basically in the blooming stage as seen by the results. Previous research on floral aroma production indicates that some plants, such as _Acacia Cyclops_ was in the bud stage [39]; however, _Osmanthus fragrans_ 'Boye Jingui' was in their early bloom stage [40]. As a result, the floral aroma of different plants has varying compositions and release patterns, which could have an impact on the pollinators' attraction to certain plants [41]. Environmental influences and the internal biological clock both have an impact on the pattern of scent emission [42]. In the diurnal variation of the full blooming stage of _Dendrobium Chrysotoxum_, the release volume of \(\alpha\)-pinene and \(\beta\)-Ocimene reached a peak at 11:00 and 14:00, respectively [43]. Under various light intensity treatments, there were noticeable variations in the content and concentration of fragrance from _Oncidium_ [PERSON] 'Sweet Fragrance' [44]. Additionally, high temperature inhibited the blooming and aroma emission of _Jasminum sambac_ Ait, while high humidity and a plentif water supply can encourage fragrance production [45]. Several components of the 14 key floral scent components determined in this research can not only participate in plant growth and development, environmental response and other physiological processes, but also have biological activities. For instance, \(\alpha\)-Farnesene plays an important role in plant defense [46] and can be used as a precursor for modern biofuel farresane production [47]. D-Limonene can be utilized as a synergistic for hygienic pesticides [48] and as a raw ingredient for artificial neroli and lemon oils, both of which have phlegmatic and anticancer properties [49]. Linalool contains antibacterial, anti-inflammatory and anti-infective properties and is frequently utilized in the synthesis of essential oils [50]. _Escherichia coli_ and _Bacillus subtilis_ are significantly inhibited by the antimicrobial activity of Germacrene D [51]. They provide a variety of fragrant qualities that are beneficial to human mood and health.