By Saima Sidik
The state has seen frequent heat waves in recent summers. As the mercury rises, plants first cool themselves by letting water evaporate, akin to sweating. Once there’s no more water in the soil, however, plants can’t afford to lose more. They close their leaves’ tiny pores to stay hydrated, but that means that gases from the air can no longer enter. That includes carbon dioxide, which photosynthesis relies on. Without a supply of carbon dioxide, photosynthesis can’t use sunlight to turn carbon dioxide into sugars; so, instead, sunlight creates toxic molecules called reactive oxygen species. These roam the cell, damaging cellular components as they go. Plants have ways of mopping up reactive oxygen species, but at high temperatures, proteins anchoring the defense mechanisms become misshapen globs. The result, Smertenko says, is the “collapse of these very sophisticated biochemical mechanisms that we call homeostasis.”
As climate change drives temperatures upward, crop plants will contend with yet more extreme weather. Estimates vary for how much yields will suffer, from very little to upward of 20%, depending on the crop, region, and severity of climate change (1). But with the global population growing and demand for animal products rising, any loss is too much. Researchers estimate that it will take about a 50% increase in food production by 2050 to meet demand (2). What’s more, rising carbon dioxide levels seem to be depleting certain crops of key nutrients through a mechanism scientists don’t yet understand (3). In short, crops’ natural resilience will be tested.
It seems imperative, then, that we better understand that natural resilience and perhaps harness it to extend the range of conditions under which plants can function. Some researchers are trying to beef up plants’ natural stress defenses using genetic engineering. Others think manipulating plants’ microbial communities might help them weather the stresses of the future. And in some cases, the type of traditional breeding that farmers have done for generations might offer answers.
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