Anthocyanins of the anthers as chemotaxonomic markers in the genus Populus L.. Differentiation between Populus nigra, Populus alba and Populus tremula. (August 2016)

• Record Type: Journal Article
• Authors: Alcalde-Eon, Cristina; García-Estévez, Ignacio; Rivas-Gonzalo, Julián C.; Rodríguez de la Cruz, David; Escribano-Bailón, María Teresa
• Is Part Of: Phytochemistry. Volume 128(2016:Aug.)
• Page Start: 35
• Page End: 49
• Publication Date: 2016-08
• Subjects: Populus nigra L. -- Populus alba L. -- Populus tremula L. -- Salicaceae -- Poplar -- HPLC-DAD-MSn -- Anthocyanins and anthocyanin-derived pigments -- Anthers; Botanical chemistry -- Periodicals; Biochemistry -- Periodicals; Botany -- Periodicals; Chimie végétale -- Périodiques; 572.2
• DOI: 10.1016/j.phytochem.2016.04.004
• Languages: English
• ISSNs: 0031-9422

Abstract

Abstract: Three main species of Popululs L. (Salicaceae) have been reported to occur in the Iberian Peninsula: Populus nigra L., Populus alba L. and Populus tremula L. The degree of pilosity of the bracts of the male catkins is a key character for their differentiation. The anthers of these poplar species possess anthocyanins that provide them a red colouration. Since these poplars are wind-pollinated and, consequently, do not need to attract pollinators, anthocyanins in the anthers might be acting as photoprotectors, shielding pollen grains from excessive sunlight. In order to verify this hypothesis, the first objective of this study was to establish if there is any relationship between the degree of pilosity of the bracts (related to the physical shading of the pollen grains) and the levels and types of anthocyanins in the anthers of these three species. This study also aimed to check the usefulness of the anthocyanins of the anthers as chemotaxonomic markers, through the study of the differences in the anthocyanin composition between these poplar species. Anthocyanins were identified from the data supplied by HPLC-DAD-MS n analyses. Seventeen different compounds, including mono-, di- and triglycosides and anthocyanin-derived pigments (F-A + dimers) have been identified. Cyanidin 3- O -glucoside was the major compound in all the samples (>60% of the total content), which may be in accordance with the photoprotective role proposed for them. However, qualitative and quantitative differences were detected among samples. Cyanidin and delphinidin 3- O -sambubiosides have been detected only in the anthers of P. tremula as well as cyanidin 3- O -(2″- O -xyloxyl)rutinoside, making them valuable chemotaxonomic markers for this species. Hierarchical Cluster and Principal Components Analyses (HCA and PCA) carried out with the anthocyanin percent composition data have allowed a separation of the samples that is in accordance with the initial classification of the samples made from the morphological characters of the specimens. Furthermore, these analyses have revealed intraspecific differences among samples that point out to different clones or varieties of a same species. Graphical abstract: The three main species of Populus L. in the Iberian Peninsula can be differentiated through the anthocyanin composition of the anthers proving the usefulness of anthocyanins as chemotaxonomic markers. Highlights: Cyanidin 3- O -glucoside is the major pigment (>60%) in all the species studied. Each species shows a specific anthocyanin profile and different total content. Some compounds have only been detected in a single species. HCA and PCA revealed correlation between anthocyanin composition and taxonomy. A photoprotective role can be ascribed to the anthocyanins of anthers from their composition.