Effects of mycorrhizal infection and soil phosphorus availability on in vitro and in vivo pollen performance in Lycopersicon esculentum (Solanaceae)

The effects of mycorrhizal infection and soil P availability on in vitro an d in vivo pollen performance were studied in two cultivars of tomato (Lycop ersicon esculentum). In the first study, plants were grown in a greenhouse under three treatment combinations: nonmycorrhizal, low P (NMPO): nonmycorr hizal. high P (NMP3) and mycorrhizal, low P (MPO). Mycorrhizal infection an d high soil P conditions significantly increased in vitro pollen tube growt h rates but not percentage of germination. In addition, pollen from NMP3 an d MPO plants sired significantly more seeds than pollen from NMPO plants in pollen mixture studies. In the second study, plants were grown initially i n a greenhouse under two treatment combinations: NMPO and MPO, After all pl ants began to flower, they were placed in experimental arrays in the field. Under open pollination, pollen from MPO plants sired significantly more se eds than pollen from NMPO plants. This result was primarily attributed to i ncreased flower production (and thus pollen production) in MPO plants. Thus , mycorrhizal infection and high soil P conditions can increase pollen qual ity (in vitro and in vivo pollen performance) as well as pollen quantity. t hereby enhancing fitness through the male function. Anthocyanin production (used to determine paternity) also affected pollen performance.