There is little information on the use of pollen in molecular research, despite the increased interest to genome editing by pollen mediated transformation. PCR is useful tool as an express-method to evaluate editing results before pollination. A direct PCR protocol for pollen suspension has been adapted without the need for DNA pre-extraction. We showed that pollenkitt is a limiting factor for successful PCR on pollen. A simple pre-washing step of pollen suspension was able to eliminate the pollenkitt and enormously affect the PCR results. All currently existing methods of delivery of the editing system to pollen are carried out in a wet medium. Our pollenkitt study helped us develop a simple and effective pollination method using wetted onion pollen grains.

Although pollination is one of the most crucial biological processes that ensures plant reproduction, its mechanisms are poorly understood. Especially in insect-mediated pollination, a pollen undergoes several attachment and detachment cycles when being transfered from anther to insect and from insect to stigma. The influence of the surface properties of pollen, insect and floral surfaces on the adhesion forces that mediate pollen transfer are poorly studied. Here, we investigate the adhesive properties of Hypochaeris radicata pollen and their dependence on pollen ageing by quantifying the pull-off forces from glass slides using centrifugation and atomic force microscopy. We found that the properties of the pollenkitt – the viscous, lipid liquid on the surface of most pollen grains – influences the forces necessary to detach a pollen from hydrophilic surfaces. Our results show that aged H. radicata pollen form weaker adhesions to hydrophilic glass than fresh ones. On the other hand, when a pollen grain ages in contact with glass, the adhesion between the two surfaces increases over time. This study shows for the first time the pollen ageing effect on the pollination mechanism.