Integrating the effects of a changing climate: stomatal responses to atmospheric humidity, air pollution and drought
Background
Reductions in stomatal aperture are frequently observed in response to exposure of plants to ozone, perhaps through an effect on Ca homeostasis. Our most recent work focusing on the responses of upland grassland show reduced stomatal response to water deficit when exposed to 40pbb ozone. It is well known that plant water deficits and the stress hormone abscisic acid will also close stomata through an impact on intra cellular calcium concentrations suggesting substantial scope for interactions between the effects of changing rainfall patterns and resulting soil drying and increases in tropospheric ozone. Ozone induced changes in stomatal behaviour will affect plant water balance, growth and gas exchange.
We also expect that stomata that are more open under mild drought will allow an increased flux of ozone into leaves and therefore increase the dose received by the leaf in a given exposure period. It is of interest to know whether the effect of ozone on leaf metabolism and growth is exacerbated by an effect of relative increases in dose as stomata fail to close or whether fundamental metabolic sensitivity is enhanced by mild water deficit. Interactions between abiotic stress signalling pathways including ABA and ethylene and oxidative stress suggest that there may be important metabolic interactions between ozone exposure and plant water relationships and between atmospheric humidity and the plant’s ABA status.
Publications
- Clayton H, Knight MR, Knight H, McAinsh MR, Hetherington AM (1999) Dissection of the ozone-induced calcium signature. Plant Journal 17: 575-579.
- Sobeih, W, Dodd, IC, Bacon, MA, Grierson, DC, Davies, WJ, (2004). Long-distance signals regulating stomatal conductance and leaf growth in tomato (Lycopersicon esculentum) plants subjected to partial rootzone drying. Journal of Experimental Botany 55: 2353-2364.
- Xie X, Wang Y, Williamson L, Holroyd GH, Taglivia C, Murchie E, Theobald, Davies WJ, Leyser HMO, Knight MR and Hetherington AM (2006). The identification of genes involved in the stomatal response to reduced atmospheric relative humidity. Current Biology 16, 882-887.
- Davies WJ. (2006) Responses of Plant Growth and Functioning to Changes in Water Supply in a Changing Climate. In, Plant Growth and Climate Change. Eds. JIL Morison and M Morecroft. Blackwells, Oxford. Pp 96-117.
- Bacon, M.A. (Ed) Water Use Efficiency of Plants. Blackwell. Oxford.