Morfologia prezentera pyłkowego i polimorfizm ziaren pyłku Taraxacum officinale F. H. Wigg. [The morphology of pollen presenter and polymorphism of pollen grains Taraxacum officinale F. H. Wigg.]

Abstract

The study of the structure of the pollen presenter of Taraxacum officinale and morphology of pollen grains was conducted based on plant material sampled from three different sites. One of them was a forest meadow situated away from the city, and the other two were located in the city centre of Lublin. Light and electron scanning microscopy were used in the study. The pollen presenter in Taraxacum officinale occurs at the upper part of the style situated over the androecium and on the outer part of the stigma. Numerous unicellular trichomes are found on the entire surface of the epidermis of the presenter. The function of the presenter consists in transferring pollen grains above the androecium and corolla petals. Its activity does not stop after pollen release from anthers. Taraxacum pollen grains represent the Crepis - type. Most frequently, they are tricolporate, radially symmetric and isopolar. In terms of the size, they are included in medium-sized grains. In the material examined, many deformed and asymmetric grains were observed, though they were marked by high viability at the level of 96.5-99%. Grains with the largest average lengths of the equatorial and polar axes were found in plants sampled from the meadow situated out of town. In the plant material from all sites, grains with disturbances of the external structure occurred.