Ecological anatomy of Syngonanthus nitens (Bong.) Ruhland and its relation to the golden grass handicrafts in Jalapão (TO), Brazil

Abstract

The Jalapão region lies within the State of Tocantins, in north Brazil. It is located within the Cerrado biome, characterized by a rainy season (October to April) and a dry season (May to September). The traditional communities of Jalapão use the scape of two morphotypes of Syngonanthus nitens (golden grass), called douradão and douradinho, to make handicrafts. The douradão type is taller and grows on the wet, clay soils of closed grasslands (campos fechados), while the douradinho is found on the wet and sandy soils of open grasslands (campos abertos). The artisans seem to favor the douradão morphotype for its longer scapes. Root, leaf, and scape anatomy of S. nitens were studied to identify environmental adaptations and structures that influence the choice of the artisans. The following characteristics are adaptive responses of S. nitens to wet soils: roots that store air, leaf epidermis and hypodermis composed of thin-walled cells, and mesophyll containing air canals. The douradão type has a broader root cortex than the douradinho type, endodermis cells with thickened outside walls, leaves with thin-walled epidermal cells and lax chlorenchyma cells, and scapes with fewer sclerenchyma cell layers and more collenchyma cell layers than the douradinho type. Because of these characteristics, douradão is more malleable and preferred by the artisans for making baskets and other large craft products.