Morfologia e viabilidade de grãos de pólen de acessos silvestres de abacaxi

Abstract

The aim of this research was to evaluate the pollen grains viability from accessions of wild pineapple using in vitro pollen germination and the growth of the polinic tube in two different temperatures and acetic carmine. In addition, the study aimed to recognize the pattern of pollen morphology of some pineapple varieties. Samples from six pineapple's accessions: Silvestre-25, I-26/803 (Ananas macrodontes), Igor (A. comosus var. erectifolius), Ananás Santo Amaro, FRF-22 and FRF-32 (A. comosus var. bracteatus) were used. The pollen grains were inoculated onto medium culture containing 10% of sucrose, 0.01% H 3BO 3, 0.01% KNO 3, 0.03% Ca(NO 3) 2.4H 2O, solidified with 1% agar and pH adjusted to 6.5. Two incubation temperatures, 25°C e 30°C were evaluated. Pollen viability was evaluated by staining with 2% acetic carmine. All varieties of A. comosus showed pollen grains of medium size, radial symmetry, oval to spheroidal, ambit 2-porate, subprolate, exine eutectic, reticulate, heterobrochate, lumens ranging from polygonal to rounded, grain-free, except for two accessions of A. macrodontes that showed big size. The best germination rates were obtained for A. macrodontes when compared to erectifolius and bracteatus. The majority of accessions presented pollen viability higher than 76% using the acetic carmine technique.