Authors: Jelena Jocković, Nemanja Rajčević, Lana Zorić, Aleksandra Radanović, Sandra Cvejić, Ljubodrag Vujisić, Dragana Miladinović, Vladimir Miklič, Jadranka Luković
Journal: Plants, 13(3), January 2024
Abstract
Although flower-pollinator interactions are known to be mediated by floral traits, not enough attention has been paid to secretory tissues and volatile components of sunflower disc florets as potentially important parameters in breeding programs. To the authors’ knowledge, this is the first integrated study aimed at better understanding the attractiveness of sunflower capitula to insects. The work combines a detailed comparative analysis of secretory tissues with the characterization of volatile organic compounds (VOCs) of disc florets across 10 wild perennial Helianthus species.
Anatomical analyses relied on cross-sections of the nectary zone obtained via a cryotechnique procedure, with light and scanning electron microscopy used for micromorphological observation. VOCs were analysed by headspace, GC-FID and GC/MS. Results revealed clear interspecific differences: H. eggertii, H. hirsutus, H. mollis, H. resinosus and H. tuberosus showed the largest disc diameters, cross-section areas, corolla lengths and nectary thickness. Thirty different VOCs were detected across the species set, with the highest yield of α-pinene observed in H. mollis.
Taken together, inflorescence features such as receptacle diameter, corolla and secretory tissue properties, and floret VOC profiles provide valuable guidelines for sunflower breeding programs aiming to maximise pollinator attractiveness and increase seed yield. These insights directly support HelEx’s objective of developing sunflower varieties that reconcile productivity with pollinator-friendly floral traits.
Open Access: Yes • Peer-reviewed: Yes • DOI: 10.3390/plants13030345
