## 3 Discussion  
The floral scent is a significant ornamental characteristic that improves the commercial value of ornamental plants [18]. _Anthurium_ is an important commodity flower worldwide, however the odors of _Anthurium_ range from pleasant to unpleasant. Therefore, it is of great significance to explore the mechanism of _Anthurium_ floral scent production and to cultivate _Anthurium_ cultivars with a pleasant fragrance. In most plants, floral scent is produced by a series of chemical compounds, including terpenids, phenylpropanoids/benzenoids, fatty acid derivatives, carotenoid derivatives, and sulfur- or nitrogen-containing compounds. In this study, the scents of _A. 'Mystral'_ were found to be composed of two major compounds: terpenids (70%) and benzenoids (28.5%). Among these compounds, eucalypt and acetic acid, phenylmethyl ester were the predominant VOCs, accounting for 57.5% and 23.2% of total VOCs, respectively. In the F1 hybrids of _A. 'Mystral'_ and _A._ 'Alabama', two plants (08-377-09 and 08-382-20) with strong fragrance and two plants (08-377-09 and 08-382-20) with weak fragrance were chosen to identify different VOC contents in these two groups of plants. In plant 08-377-09, acetic acid, phenylmethyl ester accounted for 79.6% of the total VOCs and the percentage of eucalypt was 3.8%. In plant 08-382-20, eucalypt was the major volatile compound and no acetic acid, phenylmethyl ester was detected. Interestingly, the total amounts of VOCs in plants 08-377-09 and 08-382-20 were very low, but acetic acid, phenylmethyl ester (80.5%) and eucalypt (60.5%) were still the major volatile compounds. These results indicated the major volatile compounds of the F1 hybrid progeny were consistent with the fragrant parent. A previous survey of floral scent in 147 _Anthurium_ species and hybrids showed that most plants emitted scent only in the morning (45%) and at the pistillate stage (77%) of floral development [37]. For _A. 'Mystral'_, the floral scent lasted from morning to afternoon and spadix samples at the pistillate stage of development, between 10:00 a.m. and 12:00 p.m., were taken for GC-MS analysis. For qPCR analysis, the expression levels of floral scent biosynthesis-related genes were compared across the top, middle, and base parts of the spadix. The qPCR results showed that most genes exhibited their highest level of expression in the top of the spadix (Figure 3). Thus, the top part was chosen to test the expression level of floral scent biosynthesis-related genes in the F1 hybrids (Figure 4). The inheritance of floral scent was complex, and was not simply controlled by nuclear inheritance or cytoplasmic inheritance. Our results demonstrated that having a fragrance-free parent can lead to progeny with strong fragrance, which indicates that cytoplasmic inheritance is not essential for the fragrance trait but may increase the frequency of scented progeny. In addition, several studies have demonstrated that the relationship between flower color and scent are partly linked by inheritance, as the two traits rely on shared biosynthetic pathways [38]. To explore the relationship between spathe color and spadix sents in _Anthurium andraeanum_, hybridization experiments were carried out using _A. 'Mystral'_ (with red spathes, white spadix, and strong fragrance) and _A._ 'Alabama' (with white spathes, pink spadix, and no fragrance) as parents. Among 226 F1 hybrid individuals from the cross combination (_A. 'Mystral'_ (\(\circ\)) \(\times\)_A._ 'Alabama' (\(\circ\))), 170 of 220 plants with red spathes emitted floral scent at different times of the day, and 135 of the 170 plants had white spadix. For the remaining six plants with white spathes, three individuals emitted floral scent with white or pink spadix. A similar phenomenon was also observed in the F1 hybrids from the reciprocal cross combination (_A._ 'Alabama' (\(\circ\)) \(\times\)_A._ 'Mystral' (\(\circ\))). The results suggested that there was no obvious relationship between the floral scent and flower color in _Anthurium andraeanum_.