Abstract

Plants respond to a range of environmental stimuli by adjusting the apertures of their stomatal pores or, in the longer term, altering the number of stomata that develop on new leaves. We have been investigating the environmental and molecular signals that control stomatal development using Arabidopsis thaliana mutants. We have studied a family of secreted peptide signals that act as positive or negative regulators of stomatal development. By manipulating the level of these peptides signals we have produced plants that exhibit stomatal densities ranging from 20% to 300% of wild-type. These plants are offering us the potential to investigate the optimal stomatal density for plant growth under future predicted environments.

To begin to explore the evolutionary origins of stomatal signalling pathways, we have investigated the stomatal-like structures that are present on moss sporophytes and the stomata of the lycophyte Selaginella. These moss and lycophyte stomata are able to respond to environmental stimuli in a similar manner to Arabidopsis stomata, and our cross-species complementation experiments indicate that stomata have employed the same molecular signalling mechanisms for over 400 million years.