The tree Caesalpinia paraguariensis grows in the Chaco region, Argentina. Fruits are indehiscent with many seeds. This species is an important source of wood and the fruits are consumed by cattle in Salta province. We studied seed germination under chemical, mechanical and biological scarification. Seeds from controls (without scarification) and those with biological scarification had a smaller (and similar) germination rate. The non-germinated seeds from biological treatments were mechanically scarified and their germination rate was similar to others under the mechanical treatment. Passage by digestive tracts would not enhance germination because viable seeds are still dormant due to their hard coats.
Laboratorio de Investigaciones Botánicas (LABIBO), Facultad de Ciencias Naturales, Universidad Nacional de Salta, Buenos Aires 177, (4400) Salta, Argentina. portega@miranda.ecologia.unam.mx
