# 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  
_Actinidia arguta_ is the species with the largest area of natural occurrence, both in terms of latitude and altitude [27]. This affects the large morphological diversity within the species (e.g., in terms of leaf shape, size, shape and colour of the fruit), which may account for the richest composition of flower volatile compounds, belonging to at least eight different chemical groups. Among the 120 detected compounds, about 80 were found in seven male clones of _A. arguta_ (Table 1, Figure 3). Of these, ten (lilac aldehydes, lilac alcohols, 5-Hepten-2-one, 6-methyl-, geranyl acetone, phenylethyl alcohol, 1,7-Octadien-3-ol, 2,6-dimethyl-, 1,4-Hexadiene and 5-methyl-3-(1-methylethylidene)) were detected in all seven male clones. Their relative content varied depending on the genotype, even in the same sex (Figure 3). However, about 44 compounds (55%) were detected only in one genotype, and nine in two. These were mainly esters, ketones, alcohols and straight-chain hydrocarbons. Few terpenoid volatiles, excluding linalool and ocimene derivatives, were found only in one or two genotypes. The relative content of these compounds was usually small and accounted for less than 1%. In this research, linalool derivatives represented the most important group found in _A. arguta_ flowers. Linalool, illac aldehydes and alcohols were present in almost all samples (Figure 2d). Differences in their composition in headspace samples were high, and their summed content varied between 24.3% and 92.7%. A detailed analysis showed that in few instances more than one peak was identified as representing the same compound (among illac aldehydes and alcohols). That was probably due to not distinguishing isomers by mass spectrometer. The analysis of retention indices was not conclusive either, as only partial information on the compounds analysed is available in the literature and online data. An additional detailed analysis is needed to clarify whether these peaks are indeed two isomers of the same compounds. When summing up all illac aldehydes for each genotype, it follows that differences were high. The lowest percentage of the compound was found in 'Haya Kume' (2.7%), while the headspace of the other clones contained at least 17.0% ('Weiki'). In the _A. arguta_ 'Rot', which was previously classified as _A. arguta_ var. _purpurea_ (form with red fruit), the content of illac aldehyde amounted to 25.0%. According to the latest genetic revision [1], _A. arguta_ var. _purpurea_ has been included in the _A. arguta_ variability. The highest content was observed in flowers of clone F7 (53.0%), which is a hybrid between _A. arguta_ and _A. arguta_ var. _purpurea_. This may suggest, however, that the offspring of this cross might produce a higher amount of illac aldehyde in flowers. The analysis of illac alcohol led to a similar observation. The highest percentage of the compound was observed for F7 (39.7%) and the lowest for 'Haya Kume' (5.4%). _Actinidia arguta_ 'Rot' represented a rather low content of illac alcohol in flowers (12.9%). The sum of all isomers of illac aldehyde and alcohol ranged between 38 and 53% for most of the tested genotypes. The lowest content of these compounds in the headspace has been ascertained in the 'Haya Kume' sample (8.1%), which also had the least intense aroma, organoleptically (own observation, unpublished). The content of illac alcohol and aldehyde isomers exceeded 92% in the F7 genotype. It is noteworthy that in two male  
Figure 3: Sample chromatograms with main volatile compounds in flowers of two different male _Actinidia arguta_ genotypes (**a**) “Nostino” (**b**) “Haya Kume”. samples, 'Weiki' and F7, no linalool was detected. Isomers of linalool derivatives in _A. arguta_ were identified by [PERSON] et al. [16]. The authors found two stereoisomers of linalool (S, R), four of lilac aldehydes and four of lilac alcohol.