Leaf and stem anatomical study in Mulguraea species (Verbenaceae) with insecticidal activity

FILIPPA E.; BARBOZA G. E.

Rosario

Congreso; . 2º Reunión Internacional de Ciencias Farmacéuticas –RICiFA 2012.; 2012

Univ. Nacional de Córdoba y Univ. Nac. Rosario

Introduction. Mulguraea N. O’Leary & P. Peralta comprises 11 Andean species mainly from the Patagonia, some with medicinal properties in diverse Andean cultures (1) due to their triterpenes (2). These species are also of interest by their reduced, spinescent, adpressed and mostly leaves in rosette. The anatomical information of the vegetative organs is fragmentary (3). This contribution provides a comparative analysis of leaves and stems of Mulguraea aspera (Hook.) N. O’Leary & P. Peralta, and M. tridens (Lag.) N. O’Leary & P. Peralta, with insecticidal and antifeedant properties and inhibitory activity to certain cancer cell lines (2,4), and M. echegarayii (Hieron.) N. O’Leary & P. Peralta, morphologically similar to the former species and of potential interest.                                        Material and methods. The material was fixed in FAA. Microtome preparations and epidermis peelings were analyzed. The preparations were stained with different reagents.   Results. Common leaves characters to the three species are: thick cuticle, unistrate epidermis, glandular (GT) and nonglandular trichomes (NGT), anomocytic stomata, and collateral bundles with perifloematic fibers. Mulguraea aspera and M. echegarayii have stomata in both leaf surfaces, epidermal cells with sinuate cell walls, GT with subspherical head, NGT verrucose and with a cystolith, and isolateral mesophyll; in addition,  M. aspera has also perixylematic fibers. Mulguraea tridens has hypostomatic leaves, epidermal cells with straight cell walls mixed with scarce sclereids, GT with ovoid head, NGT smooth and without cystolith, and dorsiventral mesophyll. Common stem features are: ectofloic siphonostele, early peridermis originated in the innermost cortex, and xylem rays absent. GT and NGT trichomes similar to the leaves. Only M. tridens has sclerified pith.   Discussion. Out of the ca. 60 % of the Mulguraea species analyzed, thick cuticle, anomocytic stomata and on both surfaces, the GT and unicellular NGT, and the isolateral mesophyll are the most common features of the genus and agree with the literature (3,5). Cystolith inside the trichomes, epidermal sclereids, and sclerified pith are rare and exclusive of some species.   Conclusions.The most important characters to differentiate the species are the epidermis features. Stomata present on both surfaces, large substomatic chambers, thick cuticle, sclerenchyma around the bundles, and early development of the suber are adaptative characters to the xerophitic habitat.   References 1) Villagrán C, Romo M, Victria C. Etnobotánica del sur de los andes de la primera región de Chile: un enlace entre las culturas altiplánicas y las de quebradas altas del Loa superior. Chungará. 2003; 35:73-124. 2) Pungitore CR, García M, Gianello JC, Sosa ME, Tonn CE. Insecticidal and antifeedant effects of Junellia aspera (Verbenaceae) triterpenes and derivatives on Sitophilus oryzae (Coleoptera). J. Stored Prod. Res. 2005; 41:433-443. 3) Ancibor E. Anatomía ecológica de la vegetación de La Puna de Mendoza. Anatomía foliar. Parodiana. 1992; 7:63-76. 4) Pungitore CR, Padron JM, León LG, Garcia C, Ciuffo G, Martin VS, Tonn CE. Inhibition of DNA topoisomerase I and growth inhibition of human cancer cell lines by an oleanane from Junellia aspera. Cell Mol. Biol. 2007; 53:13-17. 5) Filippa E, Barboza G. Actas VI Congreso Colombiano de Botánica. 2011. Cali.