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

Abstract

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.

Analytical strategies for in-vivo evaluation of plant volatile emissions - A review

“…An equilibrium time (12-48 h) before the beginning of sampling is usually necessary to minimise and stabilise the stresses generated by confinement [25,32,[35][36][37][38][39]. The incoming air is usually purified with charcoal filters to eliminate external BVOCs [22,25,[38][39][40][41][42][43][44] and the flow, which can reach 25 L min -1 , is controlled by a flowmeter/pump to limit water condensation and temperature increases, at the same time, avoiding losses of analytes from the trap during sampling (the socalled breakthrough effect) [38]. In this regard, Balthussen et al developed equilibrium sorptive enrichment (ESE) to concentrate volatile compounds from matrices more susceptible to the breakthrough effect [45].…”

“…For these reasons, semi-quantitative analyses that only consider the (change in) chromatographic-peak areas or percent areas are mostly carried out, as shown in Figure 4A [ [15,25,27,28,30,46,53,68]. The addition of internal standards (IS) to the original sample before analysis, is the most commonly used technique in plant BVOC quantification (Figure 4A) [38,40,44,50,51,56,66,70,78].…”

“…After sampling, the next fundamental step for the characterisation of the volatile profile of a plant sample is its analysis with the adoption of an appropriate analytical platform. When BVOCs are retained in a trapping system, two approaches to desorb the analytes can be adopted: i) solvent back-extraction (mainly with carbon disulfide, methylene chloride, hexane or dichloromethane) [20,38,40,44,[50][51][52] and ii) thermal treatment [15, 32-34, 37, 42, 43, 53, 55, 61, 68, 75, 86]. Organic solvents can easily desorb the BVOCs from the trapping material, however, this approach often require long extraction times and/or large solvent volume thus affecting the enrichment factors obtained with sampling, and it is not environmentally friendly.…”

“…One of the advantages of PTR-MS is the direct sample transfer that channels directly the sample into the detector (on-line analysis) [9]. In fact, several authors refrigerate the extraction device in the time-frame between sampling and GC-MS analysis to prevent degradation or loss of the analytes [37,43,44,53,73,81]. At the same time, GC-MS requires a solvent/thermal treatment to release the volatiles from the trapping material with the concrete risk of artefact formation or irreversible adsorption (Carbonblack or Carbotrap).…”

Um Conjunto De Planilhas Eletrônicas Para Identificação E Quantificação De Constituintes De Óleos Essenciais

“…Para o cálculo dos fatores de resposta, foram injetados ao menos um padrão (mais de um, sempre que disponível) de uma classe química (5 repetições de cada), tendo-se obtido o FR por média simples dos resultados. 19,20 Este valor foi corrigido pelo FR do padrão interno, obtendo-se o FRR conforme descrito em (2) (2) onde: Cpn é a concentração (ou massa) do padrão autêntico "n" (um monoterpeno, por exemplo); Cpi é a concentração (ou massa) do padrão interno; Apn é a área absoluta do padrão autêntico "n"; Api é a área absoluta do padrão interno.…”