Phenoplasticity of Essential Oils from Two Species of Piper (Piperaceae): Comparing Wild Specimens and Bi-Generational Monoclonal Cultivars

Abstract

This study tested the hypothesis that “clonal chemical heritability is a crucial factor for the conservation of chemical uniformity of Piper essential oils in controlled monoclonal cultivation”. We asexually propagated first and second-generation clones of two medicinal and aromatic species, Piper gaudichaudianum Kunth and Piper mollicomum Kunth (Piperaceae), for use as experimental models since they show high chemical plasticity in the wild. Leaves from wild specimens of both species, and their respective cultivated specimens, were hydrodistilled in a Clevenger-type apparatus to produce essential oils (EOs). EOs were chemically characterised by GC-MS and GC-FID. The analysis identified 63 compounds in EO of P. mollicomum, which were predominantly monoterpenes, and 59 in EO of P. gaudichaudianum, which were predominantly sesquiterpenes. Evaluation of chemical diversity and oxi-reduction indices showed a loss of chemical homology across the intergenerational cline. Chemometric analysis indicated higher chemical plasticity between wild and intergenerational specimens of P. mollicomum, than for P. gaudichaudianum. EO compounds were significantly less oxidized throughout the generations in both species. Therefore, while clonal heritability is crucial to chemical homology, significant chemical plasticity is likely to occur when cultivated from wild specimens.

Chemical Diversity and Redox Values Change as a Function of Temporal Variations of the Essential Oil of a Tropical Forest Shrub

“…This study identified and quantified the constituents of the EO from the leaves of P. lhotzkyanum in different temporal variations, with a predominant majority of sesquiterpenes. As for the predominance of this class, it is in accordance with other studies carried out with other Piper species [5][6][7]26].…”

“…The emission of volatiles is highly regulated and restricted to specific times of day, seasons of the year, and phenology, in many plant species [23]. This phenomenon has also been observed in the Piper genus [6][7][8]24], which suggests that these plants have the ability to regulate metabolic, physiological, and developmental processes through their biological clock [20,21,25].…”

“…Other factors should be taken into consideration, such as environmental and ecological conditions [31], alterations in population dynamics [32,33], ecological niche structure [34], and evolutionary drivers [9,31] such as intergenerational epigenetic variation and others [7].…”

“…Previous research has shown that species of the Piperaceae family, to which P. lhotzkyanum belongs, exhibit significant chemical phenotypic variability and diversity in relation to volatile constituents, particularly in the qualitative and quantitative aspects of their considerable variation in the qualitative and quantitative diversity of EOs volatile compounds [5]. Depending on the space and time of collection and the season of the year, for example, the chemical composition can change considerably [6,7]. However, the temporal variability (seasonal and daily) of foliar EOs of a natural population of P. lhotzkyanum has not been evaluated.…”