GPC Members Login
If you have any problems or have forgotten your login please contact [email protected]

Shedding light on the energy-efficiency of photosynthesis

Photosynthesis is one of the most crucial life processes on Earth. It's how plants get their food, using energy from sunlight to convert water and carbon dioxide from the air into sugars. It's long been thought that more than 30 percent of the energy produced during photosynthesis is wasted in a process called photorespiration.

A new study led by researchers at the University of California, Davis, suggests that photorespiration wastes little energy and instead enhances nitrate assimilation, the process that converts nitrate absorbed from the soil into protein.

"Understanding the regulation of these processes is critical for sustaining food quality under climate change," said lead author Arnold Bloom in the Department of Plant Sciences at the UC Davis College of Agricultural and Environmental Sciences. The study was published in the journal Nature Plants.

During photorespiration, the most prevalent protein on the planet, called Rubisco, combines sugars with oxygen in the atmosphere instead of carbon dioxide. This was thought to waste energy and decrease sugar synthesis. Rubisco, thus, seemed to act like the molecular equivalent of a good friend with a bad habit. Researchers speculate that photorespiration persists because most plants have reached an evolutionary dead-end.

Bloom proposes that something else is going on that shows plants aren't so stupid. Rubisco also associates with metals, either manganese or magnesium. When Rubisco associates with manganese, photorespiration proceeds along an alternative biochemical pathway, generates energy for nitrate assimilation, and promotes protein synthesis. Nearly every recent test tube study of Rubisco biochemistry, however, has been conducted in the presence of magnesium and absence of manganese, allowing for only the less energy efficient pathway for photorespiration.

"There's a lot we can learn from observing what plants are doing that can give us clear messages of how we should proceed to develop crops that are more successful under the conditions we anticipate in the next few decades," said Bloom.

Read the paper: Manganese binding to Rubisco could drive a photorespiratory pathway that increases the energy efficiency of photosynthesis.

Article source: University of California - Davis.

Image credit: Getty Images, via University of California - Davis


Plant mothers 'talk' to their embryos via the hormone auxin

While pregnancy in humans and seed development in plants look very different, parallels exist -- not least that the embryo develops in close connection with the mother. In animals, a whole network of signals from the mother is known to influence embryo development. In plants, it has been clear for a while that maternal signals regulate embryo development. However, the signal itself was unknown -- until now. Plant scientists at the Institute of Science and Technology Austria (IST Austria), Central European Institute of Technology (CEITEC) and the University of Freiburg have now found that a plant hormone, called auxin, from the mother is one of the signals that pattern the plant embryo. Their study is published in Nature Plants.

Archaeologists discover bread that predates agriculture by 4,000 years

At an archaeological site in northeastern Jordan, researchers have discovered the charred remains of a flatbread baked by hunter-gatherers 14,400 years ago. It is the oldest direct evidence of bread found to date, predating the advent of agriculture by at least 4,000 years. The findings suggest that bread production based on wild cereals may have encouraged hunter-gatherers to cultivate cereals, and thus contributed to the agricultural revolution in the Neolithic period.

Climate change-induced march of treelines halted by unsuitable soils

New research from the University of Guelph is dispelling a commonly held assumption about climate change and its impact on forests in Canada and abroad.