Anatomy, histochemical localization of lipid secretions, and its phylogenetic implications in Brazilian species of Panicum sect. Lorea (Poaceae: Panicoideae: Paniceae).

VEGA, A., M. CASTRO & F.O. ZULOAGA

ANNALS OF THE MISSOURI BOTANICAL GARDEN

MISSOURI BOTANICAL GARDEN

Año: 2008 vol. 95 p. 515 - 523

0026-6493

ABSTRACT This paper constitutes the first report of the chemical nature, and histochemical localization of secretions in Brazilian species of Panicum L. sect. Lorea Zuloaga (Poaceae, Panicoideae, Paniceae); the study also includes an anatomical analysis. Lipid secretions were found in leaf sheaths and ligular regions. Lipids accumulate in specialized epidermal cells, at times surrounding the bases of the macrohairs, and in the mesophyll. Viscous secretions have been previously reported for P. vaginiviscosum Renvoize & Zuloaga and P. acicularifolium Renvoize & Zuloaga, species in section Lorea that are analyzed anatomically here. Lipid secretions are now also reported for the first time in eight other species of section Lorea: P. bahiense Renvoize, P. chnoodes Trin., P. cipoense Renvoize & Send., P. durifolium Renvoize & Zuloaga, P. euprepes Renvoize, P. molinioides Trin., P. poliophyllum Renvoize & Zuloaga, and P. trinii Kunth. Key words: Gramineae, herbivory, lipids, Panicum, plant defenses, Poaceae, secreting epidermal cells.