Rice — one of the world’s most important cereal crops and the primary food source for more than 2 billion people — will become less nutritious as carbon dioxide levels in the atmosphere rise, potentially jeopardising the health of the billions of people who rely on the crop as their main source of food, researchers warn.
Researchers in Japan and China have found that exposing rice to the levels of carbon dioxide that are expected in the atmosphere before the end of the century results in the grain containing lower levels of protein, iron and zinc, as well as reduced levels of a number of B vitamins.
The research, published in the journal Science Advances, found on average from the varieties tested, protein levels fell by 10 per cent, zinc 8 per cent and iron 5 per cent. Levels of vitamins B1, B2, B5, and B9 also fell — though results were far more varied.
For the experiments, scientists built 17-metre-wide octagons in Japanese and Chinese rice paddies that pumped carbon dioxide to simulate the kind of CO2 concentrations expected in the next 50 years (568-590 parts per million).
“When we looked at vitamin B we looked at nine different varieties from Japan and China and they interestingly responded to high CO2 concentration in different ways,” the University of Tokyo’s Kazuhiko Kobayashi said.
“Some varieties showed a very large decline, some varieties much less a drop of vitamin contents.”
Researchers are warning the nutritional changes could have significant health implications — especially in poorer countries.
“For some populations in the world, rice is a major source of protein and also vitamins and also some other minerals,” Professor Kobayashi said, “For those people, this is not very good news.”
Director of the ARC’s Centre of Excellence for Translational Photosynthesis, Professor Bob Furbank, said in theory higher CO2 levels were a good thing for growth — but the reality proved somewhat different.
“On one hand we have the view that there will be a fertilising effect of having the extra carbon dioxide that’s available for photosynthesis — that’s certainly the case,” he said.
“This paper draws on the data they’ve produced to show there’s a detrimental effect on the quality of the rice grain in high CO2.”
Professor Furbank at the Australian National University said researchers should now study and breed varieties that will yield quality — not just quantity in high CO2 environments.
“I think it’s crucial and the work we do in [our Centre of Excellence] is more around improving yields — so we’re looking more at how to boost the amount of food available to the global population,” he said.
While higher levels of carbon dioxide have previously been linked to lower levels of certain nutrients, such as proteins, in various crops, the study is the first time researchers have also looked at the impact on vitamins.
Balmiki Education Foundation School students develop robot
BHADRAPUR— Students from Balmiki Education Foundation based in Birtamodh, Jhapa have developed several instruments including robot, drone and censor car.
Eighth grader Roshan Kumar Saha and his colleagues made a robot at the cost of Rs 180,000.
The robot developed by the students was kept at Science Exhibition of the school on Monday.