
%0 Journal Article
%A Egerton-Warbuton, LM 
%A Griffin, BJ 
%A Lamont, BB 
%T Pollen&#821;1Pistil Interactions in <I>Eucalyptus calophylla</I> Provide No Evidence of a Selection Mechanism for Aluminium Tolerance
%J Australian Journal of Botany
%D 1993/10/01
%V 41
%N 5
%P 541-552
%K 
%R https://doi.org/10.1071/BT9930541
%U https://www.publish.csiro.au/paper/BT9930541 
%X Selection for aluminium (Al) tolerance was assessed by studying pollen-pistil interactions in Eucalyptus calophylla trees colonising a 30-year-old abandoned coal mine-site (soil pH 4.3) compared with E. calophylla trees on an adjacent forest-site (soil pH 5.3). Energy-dispersive X-ray micro-analysis of reproductive tissues demonstrated that low levels of Al occurred in the stigma, lower style and unfertilised ovules of forest-site flowers. In contrast, significantly higher levels of Al were detected in all reproductive tissues of mine-site flowers. Al concentrations were higher at the base of the style than in the stigma. Al was also detected in stigmatic exudates of mine-site flowers. Selection for Al tolerance occurred in the anther of mine-site flowers as pollen from mine-site flowers germinated six-fold (15.6%) compared with forest-site pollen (2.6%) at the highest concentration of Al (22 ppm) used. However, the rate of pollen tube growth was not significantly different between mine- and forest-sites at any Al concentration. Tolerance of Al by the mine-site pollen was not shared by the progeny as there was no increase in the survival or growth of mine-site seedlings in mine soils over forest-site seedlings. Controlled pollinations between mine-/forest-site pollen and mine-site pistils demonstrated that there was no significant difference in the number of mine- or forest-site pollen tubes at any level in the style in mine-site pistils. Pollen tube abnormalities principally occurred in mine-site pistils. We concluded that there is no evidence yet for a genetically-based tolerance of Al in E. calophylla on coal mining soils. 
