London: Future heat waves could significantly increase the water needs of wheat crops, surpassing current estimates, a new British study indicated on Monday. Researchers from the University of Sheffield have discovered that during heat waves, the stomatal pores on wheat leaves open widely to cool the plant, suggesting that wheat may require much more water than anticipated under these conditions.
According to Anadolu Agency, the study conducted by Robert Caine and Holly Croft from the School of Biosciences showed that in heat wave scenarios, wheat loses several key water-saving advantages usually associated with higher atmospheric carbon dioxide levels. This is a significant finding given that wheat provides approximately 20% of the global daily caloric intake and is the most extensively cultivated crop by land area.
The study highlighted that, despite the dramatic increase in wheat yields over the past century, primarily due to nitrogen fertilizers, this progress has heightened the crop's water demand and its susceptibility to drought. Under high CO2 conditions during heat waves, the stomata of wheat open more widely, seemingly to enhance water movement and cool the plant through increased evapotranspiration. Additionally, it was observed that wheat stomata do not respond effectively to changing light levels during heat waves, regardless of CO2 concentration.
"This reduced responsiveness during heatwaves means that wheat cannot narrow its stomata effectively when light levels drop, a process that would normally help limit water loss," the research noted. The study cautioned that this inability of stomata to close could diminish drought tolerance, as plants typically close stomata significantly when light levels decrease under cooler, high CO2 conditions.
Caine emphasized, "Our findings provide a much clearer picture of how future climate conditions will affect one of the world's most important crops." He further mentioned the team's objective to explore the internal processes of the plant to understand the molecular mechanisms governing stomatal responses on different wheat leaf surfaces to rising CO2 levels and heat waves.
"If we can understand this, we may be able to adjust stomatal performance to optimise how plants grow under extreme future climates," Caine added.