Stomata and seedling establishment: sunlight and shade

Mathilda G. A. Gustavsson, Lionel Hill, Keara A. Franklin, Ashley J. Pridgeon
School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK

Following germination, seedlings must rapidly adapt to their surrounding environment. Perception of light quality via specialised photoreceptors signals the availability of sunlight for photosynthesis. Water availability and light quantity/quality are among the key factors that determine the likelihood of seedling survival. Plants regulate gas exchange through stomata on both short-term scales (through rapid movement) and long-term scales (through changes in cell size and stomatal density). Even though we know a great deal about the contribution of stomata to the ability to withstand stress in mature plants, their role in seedling establishment is much less clear.

In this study we investigate how exposure to different light qualities affect the regulation of stomatal movements in Arabidopsis thaliana seedlings. These light qualities include white light (light wavelengths between 400-700nm) supplemented with low dose ultraviolet B (UV-B – between 280-315nm), and white light supplemented with far red light (FR – between 725-735nm). These light conditions were chosen to simulate aspects of direct sunlight (which contains light within the UV part of the spectrum) and surrounding vegetation (which selectively transmits and reflects far red light) respectively. We find that both signals have effects on stomatal movements, and we investigate the underlying mechanisms mediating these stomatal responses.