How to access viability of Zanthoxylum rhoifolium seeds? A protocol of tetrazolium test as an alternative to evaluate a dormant seed

A tetrazolium test method is proposed for evaluating seed quality of Zanthoxylum rhoifolium Lam. We used seeds from two lots, which we immersed in distilled water for 8 hours and subjected to two preparations: A - lateral incision into the seed, parallel to the hilum, to expose the endosperm, and B - extraction of the embryos. We then exposed the seeds of both preparations to the tetrazolium solution at two concentrations (0.1% and 0.05%) for two periods (24 hours and 48 hours) at a temperature of 25 ºC, then the seeds were evaluated in a 2 × 8 factorial scheme (lots × treatments) and classified in viable and non-viable. We found that the best preparation for the tetrazolium assay in Zanthoxylum rhoifolium was to remove part of the seed coat, this allowed the solution to penetrate the internal tissues without damaging the embryo. There were no significant differences between concentrations of 0.1% at 24 hours and 0.05% for 48 hours. We concluded that immersion of seeds in water for 8 hours, followed by a lateral cut parallel to the hilum exposing the endosperm at a concentration of 0.1% tetrazolium for 24 hours or 0.05% for 48 hours is an efficient method for quality assessment of Zanthoxylum rhoifolium seeds.