Effects of mycorrhizal infection, soil phosphorus availability and fruit production on the male function in two cultivars of Lycopersicon esculentum

The effects of mycorrhizal infection, soil P availability and fruit product ion on the male function of reproduction were examined in two cultivars of tomato (Lycopersicon esculentum Mill.). Tomato plants were grown in a green house under three treatment combinations: non-mycorrhizal, low P (NMPO); no n-mycorrhizal, high P (NMP3); and mycorrhizal, low P (MPO). In addition, al l treatment combinations were grown both with and without fruit. Fruit prod uction decreased final leaf biomass, flower production and in vitro pollen tube growth rates, often reducing the beneficial effects of increased P upt ake. Thus, fruit production diverted resources from subsequent vegetative g rowth, flower production and pollen development. As the growing season prog ressed, mean pollen production per flower and in vitro germination and tube growth decreased. Mycorrhizal infection and high soil P conditions increas ed final leaf biomass, flower production, mean pollen production per flower (in one cultivar) and in vitro pollen tube growth rates. Thus, mycorrhizal infection and high soil P conditions increased pollen quantity and quality , thereby enhancing fitness through the male function. Similar trends in th ese treatments suggested that mycorrhizal effects on the male function were largely the result of improved P acquisition.