Viabilidade polínica e quantificação de grãos de pólen em espécies de fisális

Abstract

The aim of this study was to develop a culture medium for the evaluation of pollen viability and to determine the number of pollen grains per anther and per flower in species of Physalis. The study was developed sequentially, where pollen grains of Physalis (P. angulata,P. ixocarpa,P. minima,P. peruviana and P. pubescens) underwent germination in a culture medium developed over four phases: checking the concentration of agar and the pH, and the concentrations of sucrose, calcium nitrate and boric acid. For the pollen count, five anthers were collected from five representative specimens of each species, allowed to settle for dehiscence to take place, with lactic acid then being added to improve visualisation of the pollen grains. After 48 hours, the number of pollen grains was quantified with the help of a Neubauer chamber, and the number of pollen grains per anther determined by pre-established formula. All species were seen to have similar behaviour in their requirements for pollen grain germination, the pH of the medium being around 5.4 and the agar concentration 8 g L-1. All species display a dependence on calcium and boron for better pollen viability, especially P. minima, where the addition of boron did not provide any sharp increase in the germination percentage. As for the number of pollen grains, the species can be divided into two groups, with P. angulata,P. peruviana and P. pubescens having the highest number of pollen grains per anther and per flower compared to P. ixocarpa and P. minima.