Pfaffia roots have been commercialized as "brazilian ginseng" and crude extracts of Pfaffia glomerata roots have analgesic and disinflamatory activity. Pfaffia gnaphalioides is a perennial herb and grows in southern Córdoba, Argentina. The objective of this work is to analyze root systems in Pfaffia gnaphalioides. Growth of above and belowground organs was observed for two years in a greenhouse. Belowground organs were analyzed in situ in hillcountry shrublands, by digging soil pits. The root system is characterized by presence of a main root and superficial plagiotropic lateral roots. Lateral roots show renewal buds that give rise to new aerial innovation shoots. Unusual secondary growth is observed in the main root. A lateral meristem produces secondary cortex to the outside and conjuntive tissue and a succesion of vascular cambia to the inside. As each vascular cambium is produced, the lateral meristem outside it tends to become quiescent, returning to activity when the vascular cambium internal to it has become less active. Secondary vascular strands are arranged in concentric rings without rays. The presence of abundant parenchyma containing starch in unusual structure of Pfaffia gnaphalioides, constitutes an adaptation to xeric conditions.
Pfaffia gnaphalioides; Amaranthaceae; root-borne shoots; successive cambia; lateral meristem
