Volatilome and micromorphological analysis of two rosemary hybrids

The profile of volatile organic compounds (VOC), the composition of the essential oils (EOs) and the micro-morphology of the leaf trichomes were investigated in two rosemary hybrids,Salvia×mendizabalii(Sagredo exRosúa) Roma-Marzio & Galasso (S×m) andSalviaxlavandulacea(de Noé) Roma-Marzio & Galasso (S×l). Thephytochemical analysis highlighted the dominance of monoterpene hydrocarbons in both aroma profiles (65.8 %inS×mand 77.9 % inS×l, respectively), although they displayed different main compounds except forα-pinene (28.2 % inS×mand 24.5 % inS×l). InS×mthe EOs extracted from both fresh and dried leavesexhibited camphor (29.7 % and 25.9 %, respectively),α-pinene (21.0 % and 18.2 %, respectively) and 1,8-cineole (11.1 % and 13.6 %, respectively) as major compounds. Noteworthy is the occurrence ofβ-pinene (2.6%) in the EO dried samples, whereas sabinene and limonene were exclusive of the fresh samples. InS×lthe EOsfrom the fresh and dried leaves shared the same main compounds: camphor (24.0 % and 27.5 %, respectively),myrcene (14.9 % and 14.8 %, respectively) andα-pinene (13.1 % and 12.2 %, respectively).The micro-morphological observations on leaves proved the occurrence of non-glandular dendritic hairs withsmooth cuticle in both hybrids. The glandular trichomes include three main morphotypes: peltate, short capitateand medium-long capitate. The peltate and the short capitates are common to both hybrids, however in thepeltate the number of the head secreting cells is different, eight inS×mand sixteen inS×l. The medium-longcapitate occurs exclusively on the leaf adaxial side ofS×m