Abstract
This is the first contribution about the histochemistry of vegetative and reproductive aerial organs in the genus Piper L. Piper malgassicum accumulates alkaloids and terpenes in the epidermis and the underlying layers of parenchyma, both in the leaves, in the stems and in anthers. Some idioblasts appear to contain a large amount of secondary metabolites. The micro-anatomical analysis showed peculiar secretory structures both in the leaves, in the anthers and in the ovary. Several lipid aggregates, alkaloid droplets and calcium oxalate crystals were observed in leaves and stems, indicating their role in defence strategies, mechanical support, and pollinators attraction. In the anthers, we observed elaioplasts whose content suggest an alternative and indirect function in pollination and defence against micro-organisms. Besides, some lipid aggregates surrounded by microtubules, detected in the anthers, were recognized as lipotubuloids. The tapetum was of secretory type. Alkaloids and terpenes were widely distributed in the plant confirming the important biological role of this type of biomolecules and its functional range. In the anthers, terpene and polyphenol inclusions appeared particularly abundant in the epidermal layer, whereas calcium oxalate crystals were observed close to the ovule in the ovary at maturity.
Highlights
The genus Piper L. belongs to the family Piperaceae and includes more than 2000 species with a pantropical distribution (Quijano-Abril et al 2006), most of them from America (Ulloa Ulloa et al 2017)
We investigated the vegetative structures and the localization of secondary metabolites of a recently described species of the genus Piper L. from Madagascar, P. malgassicum Papini, Palchetti, Gori & Rota Nodari (Palchetti et al 2018, 2020), which is used for the production of local pepper named “voatsiperifery”, probably mixed with P. borbonense (Miq.) C
The plants were later transferred to the Botanical Garden of Florence (Giardino dei Semplici) Another plant was grown starting from seed directly in the laboratory at room temperature and leaves and stem of the young plant were used for further analysis After about one month of growth, when stems, leaves, and flowers had reached a suitable size (i.e., 2 mm diameter for the stem, 5 cm length for the leaf, and 1 cm length for the flower) for the light and transmission electron microscopy (TEM) analyses, sections of leaf, stem, and anthers were cut with a razor blade and a vibratome
Summary
The genus Piper L. belongs to the family Piperaceae and includes more than 2000 species with a pantropical distribution (Quijano-Abril et al 2006), most of them from America (Ulloa Ulloa et al 2017). Typical of West Polynesia, and P. cubeba L. a typical Indonesian species (Maugini et al 2014) Due to their importance, many species are cultivated beyond their native geographical region and, in some cases, have become naturalized (Smith et al 2008). Species belonging to this genus generally display an exclusive pantropical distribution They present a high number of growth forms and biomechanical organizations (Isnard et al 2012) with most species having a restricted area of distribution, while others are widespread (Marquis 2004; Quijano-Abril et al 2006)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
