The adhesion of differing types of titanium oxide nano-particles to pollen grains of Cryptomeria japonica, Chamaecyparis obtusa and Camellia japonica was investigated. In all taxa studied the adhesion of the titanium oxide nano-particles caused interference to the autofluorescence of the pollen grains. However, the degree of adhesion of the particles to the pollen grains varied, depending on the type of titanium oxide nano-particles used and also, possibly, to differences in the composition and crystalline form between the titanium oxide nano-particles. In Camellia japonica pollen grain germination was inhibited by the adhesion of titanium oxide anatase type nano-particles. While in Camellia japonica pollen grain germination was notably inhibited by UV-A irradiation combined with various differing forms of titanium oxide nano-particles.

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