UC Davis

This chapter describes the ecophysiology of Orobanchaceae seeds, especially the weedy parasitic genera Striga, Orobanche and Phelipanche. Empirical models are introduced for predicting probabilities of seed survival, loss of primary dormancy both in dry storage and during seed conditioning, and germination itself. Responses to environmental variables such as temperature and moisture can be quantified. It is argued that while several traits are conserved within species or genera, others are clearly adaptive and vary not only with seed age and between seed lots of the same species but also within seed lots, in which seed-to-seed variation can often be quantified by the normal distribution function. This may potentially allow practical use of the models to predict the behaviour of seed populations in the laboratory and in the soil seed banks.