To open or to close: species‐specific stomatal responses to simultaneously applied opposing environmental factors

• Published in: The New phytologist 2014-04, Vol.202 (2), p.499-508
• Main Authors: Merilo, Ebe, Jõesaar, Indrek, Brosché, Mikael, Kollist, Hannes
• Format: Article
• Language: English
• Subjects: air; Arabidopsis - physiology; Arabidopsis thaliana; Carbon Dioxide; Competitors; Crosstalk; Environment; Environmental changes; Environmental conditions; Environmental factors; Gas exchange; Gases; Guard cells; Hordeum vulgare; Hum; Humidity; Hydraulics; Light; Nicotiana - physiology; Nicotiana tabacum; Photosynthesis; Plant cells; Plant Stomata - physiology; Plant Transpiration; Plants; Poaceae - physiology; Signal Transduction; Species; Species Specificity; Stomata; Stomatal conductance; stomatal movement; Thellungiella salsuginea; Triticum aestivum; Water; Wheat
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/nph.12667

Plant stomatal responses to single environmental factors are well studied; however, responses to a change in two (or more) factors – a common situation in nature – have been less frequently addressed. We studied the stomatal responses to a simultaneous application of opposing environmental factors in six evolutionarily distant mono‐ and dicotyledonous herbs representing different life strategies (ruderals, competitors and stress‐tolerators) to clarify whether the crosstalk between opening‐ and closure‐inducing pathways leading to stomatal response is universal or species‐specific. Custom‐made gas exchange devices were used to study the stomatal responses to a simultaneous application of two opposing factors: decreased/increased CO₂ concentration and light availability or reduced air humidity. The studied species responded similarly to changes in single environmental factors, but showed species‐specific and nonadditive responses to two simultaneously applied opposing factors. The stomata of the ruderals Arabidopsis thaliana and Thellungiella salsuginea (previously Thellungiella halophila) always opened, whereas those of competitor‐ruderals either closed in all two‐factor combinations (Triticum aestivum), remained relatively unchanged (Nicotiana tabacum) or showed a response dominated by reduced air humidity (Hordeum vulgare). Our results, indicating that in changing environmental conditions species‐specific stomatal responses are evident that cannot be predicted from studying one factor at a time, might be interesting for stomatal modellers, too.