Anatomy of rhizome of Smilax goyazana A. DC. (Smilacaceae)

Abstract

Smilax goyazana is a very common shrub in cerrado vegetation. Plants of the genus Smilax are known by their significative production of saponins of medicinal interest. Rhizomes of Smilax goyazana were characterized anatomically. The one-layered epidermis is composed of cells with a great basal nucleus and citoplasm with much lipids and tannins; the epidermis also associates with a sclerified exodermis. Stomata were observed. The cortex presents poorly differentiated fibrovascular bundles. The parenchyma at the limit between cortex and central cylinder appears to originate new vascular bundles. Progressive sclerification occurs in this region of transition. The central cylinder is rich in oxalate crystals and some cells accumulate starch or tannins. The vascular bundles are composed of two vessel elements; a layer of parenchyma, phloem and protoxylem involves each one. Moreover, each vascular bundle is involved by an endodermis. Some bundles present duplicated vessel elements. The vessel elements are very long, recurved, with composed perforation plaque, and scalariform punctuations. The sieve elements present simple sieve plates, which range from transverse to very oblique, with elliptical lateral sieve areas.