Passive Origins of Stomatal Control in Vascular Plants

• Published in: Science (American Association for the Advancement of Science) 2011-02, Vol.331 (6017), p.582-585
• Main Authors: Brodribb, Tim J, McAdam, Scott A.M
• Format: Article
• Language: English
• Subjects: Abscisic Acid - metabolism; Abscisic Acid - pharmacology; Active control; Angiosperms; Apertures; Biological and medical sciences; Biological Evolution; Carbon; Cycadopsida - metabolism; Cycadopsida - physiology; Evolution & development; Ferns; Ferns - metabolism; Ferns - physiology; Fundamental and applied biological sciences. Psychology; Guard cells; Leaves; Light; Lycopodiaceae - metabolism; Lycopodiaceae - physiology; Magnoliopsida - metabolism; Magnoliopsida - physiology; Metabolism; Modeling; Photosynthesis; Plant biology; Plant cells; Plant Epidermis - metabolism; Plant Leaves - metabolism; Plant physiology and development; Plant Stomata - cytology; Plant Stomata - physiology; Plant Transpiration; Plants; Stimuli; Stomata; Vapor Pressure; Vascular plants; Water; Water - metabolism; Water and solutes. Absorption, translocation and permeability; Water balance; Water flow; Water loss
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1197985

Carbon and water flow between plants and the atmosphere is regulated by the opening and closing of minute stomatal pores in surfaces of leaves. By changing the aperture of stomata, plants regulate water loss and photosynthetic carbon gain in response to many environmental stimuli, but stomatal movements cannot yet be reliably predicted. We found that the complexity that characterizes stomatal control in seed plants is absent in early-diverging vascular plant lineages. Lycophyte and fern stomata are shown to lack key responses to abscisic acid and epidermal cell turgor, making their behavior highly predictable. These results indicate that a fundamental transition from passive to active metabolic control of plant water balance occurred after the divergence of ferns about 360 million years ago.