UI professor researches photosynthesis to increase food supply

By Earn Saenmuk

According to a paper published by the scientific journal PLOS ONE, the world food supply will not be enough to sustain the growing global population by 2050. While some governments have tried to limit population growth — like China — a University professor is looking at a different way to solve the problem: increasing the food supply through photosynthesis.

Stephen Long, professor of plant biology and crop sciences, is looking for a way to increase the amount of grains harvested each season by boosting photosynthesis in crops. The research focuses on improving photosynthesis in C3 plants, which include rice, wheat, maize and cassava, since they are the main source of calories for an average diet.

“We’re trying to boost photosynthesis to get more productivity,” Long said. “We’ve reached the stage where our conventional methods have almost reached their limits.”

He explained that this conventional method involves crossing plants. In this process, the researcher identifies a main property in one plant and crosses it with a second plant until it obtains the first plant’s property.

The new method, however, is called genetic engineering, Long said. Most of the time, the radiation makes the plant worse, but sometimes, it improves the plant, he said.

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“About 80 percent of our soybeans are genetically engineered,” Long said. “We know that that is responsible for about 30 percent of the yield increase.”

Haley Ahlers, communication coordinator for the Realizing Increased Photosynthetic Efficiency project, said the research is done in cooperation with scholars from the University and many other institutions around the world.

Long said the other techniques may have reached their limits, so the scientists will be focusing on this new solution.

The process of photosynthesis, Long said, is complicated. It has about 160 steps but can be explained in a simpler form.

“Plants trap light with chlorophylls, then the chlorophylls transfer the energy to reductants,” Long said. “At the same time carbon dioxide is trapped, and then the reductant is used to reduce that carbohydrate.”

Long said that the team has to consider many different factors in order to improve photosynthesis.

“It’s like looking at a car-production line,” he said. “We find out which process we should improve in order to make the production better, and we focus on that.”

The research is being done on tobacco, also a C3 plant, because it is easy to make genetic changes to it, Long said. He explained that the group makes about 10 changes each year. After they make the change, they put the plants out in the field and measure the mass at the end of the year to see if there is any improvement.

Charles Pignon, graduate student in crop sciences, is a member of Long’s research team. He collects the data that shows how much carbon dioxide is being used for photosynthesis and whether the rate improves after the modification.

“The photosynthesis rate is increasing,” Pignon said. “We measure how much carbon dioxide is entering the plant, how much goes through it, then calculate how much energy we get.”

Another aspect of the research is reducing energy and carbohydrates wasted, Long said. Photorespiration, for example, causes the loss of carbohydrates and reduces the efficiency of photosynthesis. The same goes for too much light, Long said.

“The upper leaves actually get too much light, so that light can actually be damaging,” he said. “One of the things we’re looking at is how we can change that as well.”

Long said that creating more food does not only accommodate the growing population but also the growing demand of meat, which results in a much greater need for grain and animal feed.

“Even though (the) population might increase by 35 percent, we might need 85 percent more food by 2050,” he said.

Long said because the demand for grain increases, the price of food in some parts of the world rises. While it may not affect wealthy countries where food is generally cheaper, some countries where 60 percent of household income goes to food can suffer significantly, he said.

“If you can’t meet that demand, then the price rises,” he said. “It’s not the people who are eating meat that will suffer from that; it’s the poorest.”

As the price of food increases, the money spent will be more precious than the land that we are not using for agriculture, Long said.

“Imagine what would happen to the Amazon rainforest,” he said. “Because people are starving, they are going to say, ‘We come before the Amazon rainforest.’”

Long said getting more productivity from what land we are using has a number of benefits. Although the research doesn’t solve drought problems, it still makes an impact to everyone in agriculture.

“The good thing about improving photosynthesis is it should help crop yield anywhere in the world,” Long said.

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