Rising ozone is already decimating corn crops: Scientists find pollution levels in India and China have cut yields by 10 per cent
- Experts explored how rising ozone levels impacted growth in a corn field
- Ozone is released by burning fossil fuels and can stunt plant development
- Two common commercial corn varieties are particularly vulnerable to its effects
- Studying ozone’s impacts may help experts to develop more resistant strains
Rising ground-based ozone levels are already decimating corn crops in regions such as India and China, with researchers predicting yield losses of around 10 per cent.
Ozone — which is released as a by product of fossil fuel usage — effectively prematurely ages the crops and makes them less efficient at making energy to grow.
Unlike other emissions like carbon dioxide and methane, however, its impact of plant production has gone largely unnoticed.
Researchers found that two of the most common commercial varieties of the popular vegetable suffer particularly badly when exposed to more of the gas.
The resulting reduction of crop yields match those caused by droughts.
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Rising ground-based ozone levels are already decimating corn crops in regions such as India and China, with researchers predicting yield losses of around 10 per cent
Crop scientists Lisa Ainsworth of the US Department of Agriculture and colleagues measured how increasing atmospheric ozone levels in a field impacted corn growth and yields using a sophisticated emission system that monitors wind conditions to maintain a chosen dose of the target gas.
‘Ozone enters plants the same way carbon dioxide does: It diffuses from the atmosphere into the leaf,’ said Dr Ainsworth.
‘Carbon dioxide is a nutrient for plants. All the carbon that ends up in the grain comes through the leaf first.’
Ozone is a highly reactive molecule, however, which damages biological tissues and impairs photosynthetic carbon capture in plant leaves.’
‘Basically, ozone accelerates the ageing of the leaf,’ said paper co-author and plant biologist Andrew Leakey of the University of Illinois.
‘Carbon dioxide is a nutrient for plants. All the carbon that ends up in the grain comes through the leaf first.’
‘But ozone is a highly reactive molecule that damages biological tissues and impairs photosynthetic carbon capture in plant leaves. Even background levels of ozone do some damage.’
‘Our research suggests that current ozone levels decrease corn yields by as much as 10 per cent.’
‘That’s as much as drought or flooding or any single pest or disease, but this is a relatively unstudied component of yield loss in the U.S.’
Ozone — which is released as a by product of fossil fuel usage — effectively prematurely ages the crops and makes them less efficient at making energy to grow
The researchers experiment with 45 hybrid corn plants, representing all major types of corn including broom, dent and flint corn as well as popcorn.
They discovered that some members of the corn family are more susceptible to diminishing yields when ozone air pollution levels are high.
‘We found two maize lines whose offspring were more sensitive to ozone pollution, regardless of which other types of corn we bred them with,’ Dr Leakey said.
‘Their genetic deficiencies manifested in different ways when exposed to the high ozone conditions.’
Discovering the genetic underpinnings of these differences could help plant scientists develop ozone-resistant corn, they added.
Sadly, the exact genetic make-up of commercial crops is a closely-kept secret so adapting them to air pollution will have to be undertaken by breeders.
‘We don’t know if these corn varieties have the same Achilles’ heels’ Dr Leakey said.
‘Breeders would not know about these differences since they are not apparent under clean-air conditions.’
Researchers found that two of the most common commercial varieties of the popular vegetable suffer particularly badly when exposed to more of the gas
‘The level that we’re fumigating to in this study is a level that is commonly found today in China and India,’ said Dr Ainsworth.
‘So, it’s not excessively high, even though we’re using a concentration that is two-and-a-half times the level of background ozone in central Illinois.’
‘It’s important to understand how plants are going to respond to climate change before the climate changes,’ Dr Leakey added.
‘That is the only way we can find the solutions that will be needed in the future.’
The full findings of the study were published in the journal Global Change Biology.
