Scientists working in Edinburgh claim that they have made a step towards breeding crops that can thrive in warming climates, thanks to new insights into how temperature and light affect plant development. They said their work will be needed to develop crop varieties that can cope with the effects of climate change.  

Although it is not clear exactly what effects our actions will have on future growing conditions, scientists believe that new crop diseases will emerge, and existing threats will spread to new areas. For some growing regions (though probably not Western Europe) water will become scarcer. Everywhere, higher levels of CO2 in the atmosphere, more extreme weather events and higher average temperatures could mean crop yields plateau or fall unless radical adaptation measures are taken and there is concerted action to cut emissions and avoid more hostile changes to the climate.

Two scientific studies by researchers at the University of Edinburgh have shown that warm temperatures have important and unexpected roles in controlling how plants grow and when they flower.

Scientists studied the effects of light and temperature on seedlings of a small cress plant known as Arabidopsis, which is often used in such experiments. They were surprised to find that at high temperatures, light causes seedling stems to develop in the same way that they normally would in shade or darkness.

This is the opposite of how plants behave at cooler temperatures, when light inhibits stem growth.

In a second study using the same cress plant, they looked at how seasonal flowering is promoted by lengthening summer days and by rising temperatures. Researchers created a mathematical model of the factors that control growth and flowering, and used this to predict plant behaviour, before recreating these conditions in a lab and experimenting by growing plants to validate their findings.

Though the Edinburgh team gained insights which they said could aid the development of crops that can adapt to changing climates, the scientists are still not certain why temperature influences plants in these ways. They suggest that plants may associate hot weather with a risk of drought, and so grow and flower quickly to reproduce before they die.

Dr Karen Halliday, of the University of Edinburgh's School of Biological Sciences, who led both studies, said, "In the past, scientists had paid little attention to the influence of temperature on plant growth, but now there is fresh focus on this influential environmental factor. Collectively, these findings could be valuable in breeding plants for warm climates and ensuring food security."