It can take ages to meet the right partner. So much so that plants lost their patience millions of years ago and thought up something else: the art of selfing. Many flowering plants are indeed capable of extensive in-breeding - by way of a rather subtle form of hermaphroditism - to ensure their spread and survival. The common mouse-ear cress, Arabidopsis thaliana , which has become the model plant for botanists, is revealing how many plants are able to perpetuate their species by letting their pollen fertilise their own pistil. Which prompts the question: how does any given plant species avoid self-fertilisation in the first place? The answer, or at least part of it, is: the S locus. The S locus carries two genes whose protein products - SCR and SRK - are directly involved in A.thaliana 's capacity to self-pollinate or not, and may well illustrate the pathway used by many other plants.
展开▼
