Floral Scent and Nectar Sugar Composition of Temnadenia odorifera (Apocynoideae, Apocynaceae)

Temnadenia odorifera is an endemic species from the Brazilian Atlantic Forest. This study was developed in order to identify the volatile compounds emitted by the living flowers and nectar, to evaluate the temporal pattern of scent emission, and the sugars composition of its nectar. Analyses of the flower scent by dynamic headspace in vivo, of nectar sugar composition and studies on floral biology were performed. Twenty-three volatile compounds were identified in the flowers scent. The total amount of odor emitted by flowers varied significantly throughout anthesis, ranging from 10232.7 ng g-1 (9 to 12 h) to 620.2 ng g-1 (15 to 18 h). 2-Phenylethanol and (E)-cinnamyl alcohol were the major compounds. Concentration ratio between disaccharides and the sum of hexoses ranged from 2.3 to 3.04, which can be correlated to the physiological needs inherent to big bees, the most frequent insects in T. odorifera. Analysis of the chemical composition of T. odorifera flowers provided a broader understanding of the mechanisms responsible for plant-insect interactions.

香冠藤（Temnadenia odorifera）为巴西大西洋森林的特有物种。本研究旨在鉴定活体花朵与花蜜所释放的挥发性化合物，评估花香释放的时间模式，并分析其花蜜的糖组成。研究采用活体动态顶空法开展花香成分分析、花蜜糖组成分析，并进行了花部生物学研究。共在花香中鉴定出23种挥发性化合物。花朵释放的总气味量在整个开花期内存在显著差异，变化范围为10232.7 ng·g⁻¹（9时至12时）至620.2 ng·g⁻¹（15时至18时）。2-苯乙醇（2-Phenylethanol）与反式肉桂醇（(E)-cinnamyl alcohol）为其中的主要组分。花蜜中二糖与己糖总和的浓度比介于2.3至3.04之间，这与香冠藤最常见的访花昆虫——大型蜂类的固有生理需求相关。对香冠藤花朵化学成分的分析，为揭示植物与昆虫互作的内在机制提供了更全面的认知。