The Effect of Elevated Temperature on Stomatal Development in Arabidopsis thaliana

Abstract

Stomata are small pores in the leaf epidermis, each surrounded by a pair of guard cells, that mediate gas exchange between the plant and the environment. Their development is greatly influenced by environmental conditions such as light intensity, carbon dioxide (CO2) levels, and temperature. With global temperatures rising, understanding how stomatal patterning is regulated in the increasingly warmer climate is becoming paramount. This study addressed stomatal developmental response to elevated temperature (ET) in plants deficient in key signalling pathway components involved in stomatal function and development in Arabidopsis thaliana to identify potential new actors in this response. The mutant lines were grown at 30°C/26°C day/night (ET) and at 23°C/19°C day/night (control temperature, CT). Analysis of stomatal density (SD), stomatal ratio (SR) and stomatal index (SI) was performed. We found that SD generally decreased in response to ET. SR was mostly not affected by ET. SI increased on the abaxial side in the control line Col-0 and mitogen-activated protein kinases 3 and 6 (MPK3/6) overexpressor lines MPK3OX and MPK6OX when grown at 30°C, suggesting the role of MPK3/6 in the regulation of the response of stomatal development to ET. The mutant line raf27-2 initially showed increased SD in response to ET. However, this effect was not seen in a repeat experiment grown under the same conditions on a different shelf of the growth cabinet, suggesting an unknown inconsistency across the growth cabinet. A further investigation of the role of RAF27 in the temperature response is required.