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Summary• The relationship between floral morphology and electrostatic pollination was studied here. To test the effects of floral morphology on pollen deposition on the stigma and other floral parts by means of electrostatic forces, metal replicas of almond ( Amygdalus communis ) flowers were constructed and then dusted with electrostatically charged and uncharged almond pollen. The pollen was applied to the flowers with a specially designed electrostatic powder-coating device.• Pollen deposition on the flower was found to be higher when the pollen was electrostatically charged than when it was not. Most of the charged pollen grains were deposited on the corolla extremities and on the stigma, whereas uncharged pollen grains were evenly distributed on the entire flower.• Stigma exsertion was the most important morphological feature of the flower promoting pollen deposition on the stigma when electrostatic charge was used. Large flowers with corollas showed higher electrodeposition on the corolla than smaller, narrower ones.• These results collectively imply that morphological features of a plant might be adaptations to take advantage of electrostatic forces. This provided us with a very important tool for future research on floral morphology and pollination biology.

Abstract. This paper reviews research on the role of electrostatic forces in pollination, both in natural and in agricultural systems. Researchers from various fields of biological studies have reported phenomena which they related to electrostatic forces. The theory of electrostatically mediated pollen transfer between insect pollinators and the flowers they visit is described, including recent studies which confirmed that the accumulated charges on airborne honey bees are sufficient for non-contact pollen detachment by electrostatic forces (i.e., electrostatic pollination). The most important morphological features in flower adaptiveness to electrostatic pollination were determined by means of two theoretical models of a flower exposed to an approaching charged cloud of pollen; they are style length and flower opening. Supplementary pollination by using electrostatic techniques is reported , and its possible importance in modern agriculture is discussed.

SUMMARYPollen counting is an important element of research in pollination, and the majority of current methods involve manual counting. An image-processing technique has been developed for accurate counting and sizing of small particles, and this was tested on almond pollen grains. Our automatic process was found to be several times faster than manual counting and more accurate, with an average error of only 3 %. Because of its simplicity, it is an attractive tool for research on such topics as pollen viability or germination. It was found that in the methods using vials there were 'residues' of c. 17% on the vial walls and on the handling tools. In addition, the first drop from each vial contained, on average, 1-65 times more grains than the average number of grains in all drops, whereas the last drop from each vial contained fewer grains than the average. This phenomenon was correlated with the non-uniform pollen distribution in the suspension. An automatic counting system is therefore, recommended, to avoid the problem, otherwise a calibration procedure should be used that accounts for both the residues on the tools and the non-uniformity of contents of sample drops.

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