Pollen starch reserves in tomato relatives: Ecophysiological implications

Abstract

The presence or absence of starch in microspore development and in pollen grains was recorded in eleven wild tomato species (Solanum sect. Lycopersicon) and two close relatives (S. lycopersicoides and S. sitiens). In all the species starch started to accumulate in the early microspore bicellular stage and continued until the cytoplasm was filled. At flower anthesis, pollen grains were mostly starchless in the wild tomatoes, except in S. pennellii, which had starchy pollen. Starchy pollen is also present in the two related species. The latter two species had larger pollen grains and grow in drier environments than the other species. The heterogeneity of pollen starch content among all these species, supposed to have the same pollination mechanism, is a new finding supporting the idea that starch content and pollination mechanism do not necessarily influence each other. The presence of starchy pollen in the self-incompatible species, which grow in the driest environments, raises questions regarding the relationship between carbohydrates content and pollen survival. © 2007 Taylor & Francis.