Oenothera biennis L. (Evening Primrose or Evening Star) is a species of interest given by its medicinal and nutritive properties as well as for its economic value. It is also one of the earliest plant models in genetics and cytogenetics. Currently, O. biennis is cultivated mostly for its seeds, from which is extracted the Evening Primrose oil (EPO), rich in γ-linolenic acid. EPO is commercialized in diverse products, from nutritional supplements to cosmetics. The rest of the plant has medicinal value, being used to treat asthma, cough, intestinal pain, inflammation, and as an analgesic. The present study focuses on the morpho-anatomical characteristics of the main vegetative organs of O. biennis. For this study, the plant was collected from Macea village, Arad County, in the years 2015 and 2017. Root (lower part and upper part), stem (lower part and upper part), petiole and leaf samples were prepared according to current optical microscopy and scanning electron microscopy techniques, then observed and photographed with Novex-Holland optical microscope and Quanta 250 SEM microscope, respectively. The analyzed samples have shown the presence of a secondary structure at the level of central cylinder for both the root and the stem, a casparyan type endodermis, starchy liberian parenchyma, and numerous cells with calcium oxalate raphides. The pith had a thick, parenchymatic-cellulosic aspect, of meatic type. In the stem, the pith can present aeriferous cavities of irregular shapes.The root cortex presents what appear to be mucilage cavities. There has been observed a difference between the inferior part (towards the apex) and the superior part (towards the base) of the root and stem regarding the number of cells, their size, and their dispositions. Both the stem and the foliar limb present on their epidermis two types of trichomes: long and straight, short and curved. The foliar limb is amphistomatic and has additional secretory hairs. Our results contribute to a better understanding of this plant’s structure and possible storage areas for active compounds of pharmacological interest.

Oenothera biennis, morpho-anatomy, root, stem, leaf, petiole, SEM

biology

Presentation: oral