Characterization and evaluation of Berberis microphylla G. Forst pollen grains

Abstract

Berberis microphylla, commonly known as “calafate”, is a non-timber forest product native from Patagonia, and its berries possess highlighted nutraceutical value. The objective of this research was to describe the morphology and anatomy of pollen grains of Berberis microphylla G. Forst genotypes growing spontaneously on the island of Tierra del Fuego (Argentina), and evaluate their vitality and germination. Pollen grain diameter varied from 40 to 47.26 μm, the pollen grains of 124 and 201 genotypes being significantly smaller than the others. Vitality measured by DAPI methodology was also variable among genotypes, although always about 50%. In vitro germination of pollen grains measured one day after the flowers were collected was very high for some genotypes (near 80%), and then decreased after 21 days of storage, except for genotype 123 whose germination value increased from 44.34 to 69%. The significant variability found in pollen performance (size, viability and germination) among B. microphylla genotypes from a natural population could be interpreted as an enhanced survival strategy to maximize reproduction fitness, with a marked capacity of response to environmental changes. High viable pollen frequency together with germination percentages observed in all the genotypes tested could indicate a good fertilization process. The correlation observed between size and germination percentage could be used as markers of pollen grain performance, paving the way for possible B. microphylla breeding.