Plants elongate their stems when grown at high temperature to facilitate the cooling of their leaves, according to new research from the University of Bristol published today in Current Biology. Understanding why plants alter their architecture in response to heat is important as increasing global temperatures pose a threat to future food production.
Although scientists have made significant advances in understanding how plants elongate at high temperature, little is known of the physiological consequences of this response. To investigate these consequences, the researchers, led by Kerry Franklin and Professor Alistair Hetherington in Bristol’s School of Biological Sciences , studied thale cress (Arabidopsis thaliana), a small flowering plant which is a popular model species in plant biology and genetics.
When grown at higher temperatures, plants have an elongated, spindly architecture and develop fewer leaf pores, known as stomata. However, in spite of having a reduced number of stomata, the elongated Arabidopsis thaliana plants grown by the team displayed greater water loss and leaf evaporative cooling.
The researchers suggest that the increased spacing of leaves observed in high temperature-grown plants may promote the diffusion of water vapour from stomata, thereby enhancing the cooling process.
Franklin said: "Temperature and water availability are major factors affecting plant yield. Understanding the relationship between temperature, plant architecture and water use is therefore essential for maximising future crop production and ensuring food security in a changing climate."
Crawford AJ, McLachlan, D, Hetherington, AM & Franklin, KA. (2012) ’High Temperature Exposure Increases Plant Cooling Capacity’, Current Biology
(Left) Arabidopsis thaliana, the model plant species, grown at 22oC (top) and 28oC (bottom). (Right) Thermal images of 22oC-grown (top) and 28oC-grown (bottom) Arabidopsis plants moved to 28oC.
Image by Kerry Franklin