Study on the Biological Characteristics of Pollination of Gentiana rigescens Franch.

PurposeThe pollen viability, pollen grain morphology, stigma receptivity, pollinator and flower visiting behavior of Gentiana rigescens Franch. were studied to clarify the pollination biological characteristics of G. rigescens.

MethodsThe pollen viability was detected by TTC staining, acetic acid magenta staining, I₂-KI staining and peroxidase method. Pollen morphology was observed by FEIQUANTA 200 scanning electron microscope. Stigma receptivity was determined by benzidine-hydrogen peroxide method and the species and frequency of flower visitors were recorded manually.

ResultsThe peroxidase method was the most suitable method to determine the pollen vigor of G. rigescens, and the pollen vigor reached 65.98% (on the 3rd day after flowering). The pollen vitality changed during one day. The pollen vitality reached the highest (64.71%) at 14:00 and then decreased significantly on the very day of flowering. The pollen grains are spherical in appearance, with 3 germinal aperture, which belong to the N3 type pollen, and the outer wall of the pollen forms a grid. The stigma exhibited strong stigma acceptability, which reached 57.69% and 63.16%, respectively on the 4th and 5th day of flowering. The flower-visiting insects of G. rigescens mainly include bees and ants, the number of flower-visiting insects was the largest from 11:30 to 12:30 during a day. However, the most important pollinator was bees.

Conclusion These results are of great significance for revealing the law of sexual reproduction of G. rigecens. At the same time, it can provide reference for the protection, introduction and cultivation of G. rigescens.