Pollenkitt formation in Ilex paraguariensis A.St.Hil. (Aquifoliaceae) R. P. Santos 1 , J. E. A. Mariath 1 , and M. Hesse 2 1 Department of Botany, Biosciences Institute, Federal University of Rio Grande do Sul, Porto Alegre, Brazil 2 Institute of Botany and Botanical Garden, University of Vienna, Wien, Austria Received October 24, 2002; accepted December 2, 2002 Published online: March 20, 2003 Ó Springer-Verlag 2003 Abstract. We investigated the cellular and organelle transformations during the formation of the pollenkitt in the secretory tapetum of Ilex paraguariensis. After the dissolution of the callose surrounding the young microspores, the elaioplasts of the tapetum produce many glob- ules of saturated and unsaturated lipids (plasto- globules). Further on, oleosomes with unsaturated lipids, synthesized in the endoplasmic reticulum, accumulate in the tapetal cytoplasm. In contrast to other species, the plastoglobule production seems to precede the oleosome synthesis. The tapetum shows signs of cellular maturation in the late vacuolated microspore stage, when the plastoglobules and oleosomes coalesce and form the pollenkitt mass. In mature stages of the tapetum the pollenkitt is released into the loculus. Finally, it is mainly deposited on the exine, according to the entomophilous character of this species. The mode of pollenkitt formation in Ilex paraguariensis and its transfer to the pollen surface is slightly dissimilar to other Angiosperms. Key words: Ilex paraguariensis, mate´, Aquifolia- ceae, pollenkitt, tapetum, plastoglobules, oleo- somes. Introduction Ilex paraguariensis A.St.Hil., the mate´, is a member of the Aquifoliaceae and has a great economic importance in the Mercosul, in South America. This plant is used like tea, and in the preparation of the ‘‘chimarra˜o’’, a popular hot drink consumed in the south of Brazil. Ilex paraguariensis is also used in the pharmaceutical industry by its stimulating action on the central nervous system. This property is due to the presence of derivative methylxanthines, as caffeine and teobromine (Ricco et al. 1995). Other important substances found in the Ilex species are phenols and phenolic acids, phenyl propanoids, anthocya- nines, flavonoids, terpenoids, alkaloids, amino acids, alcohols and alkanes, carbohydrates, vitamins and carotenoids (Galle 1997). The studies of the floral biology of Ilex paraguariensis ratified the predominance in that species of entomophilous pollination (Ayub 1999). It was verified that pollen transfer by wind is nonexistent or very reduced. Ilex paraguariensis has a secretory tapetum, which Plant Syst. Evol. 237: 185–198 (2003) DOI 10.1007/s00606-002-0257-2