# Comparative Analysis of Volatile Compounds in Flowers of Different _Actinidia_ Species
## 2 Results and Discussion
### Diversity of Volatile Compounds in Flowers of Different A. arguta Genoptypes
More than ten ester compounds were identified in all samples of _A. arguta_. Of these, butanoic acid, 3-methyl- and 3-methylbutyl ester, a constituent of banana fruit, tomatoes and alcohol beverages (e.g., cognac or cider), was found to be the compound that may have an impact on the aroma. The ester was found in four male samples. The content in two ('Nostino' and 'Haya Kume') amounted to less than 0.5%, and in other two ('Rot' and 'Weiki') to 2.1 and 3.3%, respectively. More esters were found in this research than in previous ones in general. Reports of using SMPE sampling for the analysis of fatty acid esters, whose particles are heavier than those identified in our research [28], suggest that the sampling methods used contributed to a better ester detection in this research. Only three aldehydes (furfurral, 5-methylfurral and nonanal) were detected in this research. Furfurral and 5-methylfurral were present in small amounts in the 'Nostino' sample (1.3% and 0.3%, respectively) and nonanal in 'Joker' (0.1%), whereas [PERSON] et al. [23] identified 11 different aldehydes. Four, including nonanal, were present in all samples. Ketones were detected in two male genotypes: 'Nostino' and 'Haya Kume', but the amounts of particular compounds were different. Most of them also amounted to less than 1% of the total headspace, but the contents of one ketone--3-Octanone, detected in 'Haya Kume'--were higher and reached 4.2%. The analysis of ketones in both studies shows that genotypes tend to have individual combinations of these compounds or almost no ketones. High differences in relative content were also noticed for two alcohols: 1-Butanol, 2-methyl- and 1-Butanol, 3-methyl. Genotypes with a high content of ilac compounds (F7) presented a low content of these alcohols (1.5% in F7 headspace); and, conversely, where a low content of ilac compounds was found, a high percentage of these alcohols was observed (up to 49.4% in 'Haya Kume'). These two alcohols were also found by [PERSON] et al. [23] in the headspace of _A. arguta_ samples. In our and [PERSON] et al. 's [23] research, one or the other compound was present in the sample, but never both of them simultaneously. 1-Octen-3-ol was also found in previous research, but only in two genotypes. Generally, few alcohols detected in our research were also found by other researchers, but a few different compounds were also identified. Some were chemically similar, e.g., in terms of the same base, but different in the location of a double chemical bond or substituent. This usually has a significant impact on a compound's characteristics. Straight-chain hydrocarbons, like acids, were rather uncharacteristic for _A. arguta_ flower volatiles. As in our analysis, [PERSON] et al. [23] detected only few hydrocarbons, and most were found in just one genotype. In this work, only a few acid compounds were found, and they do not seem to have an impact on the aroma of _A. arguta_ flowers. Summing up, ilac compounds are the most important compounds in most _A. arguta_ male genotypes. Alcohols also play an important part in the aroma, but a number of these substances were found only in a few or just one genotype. Some alcohols represent regular components of the aroma but differ in their relative content. Moreover, every genotype/variety has its own unique volatiles composition. This offers the possibility of selecting genotypes with a higher content of volatile compounds, and enhances their attractiveness for pollinating insects for actinidia commercial orchards.