Photosynthesis

The flag leaf is the last to emerge, indicating the transition from crop growth to grain production. Photosynthesis in this leaf provides the majority of the carbohydrates needed for grain filling--so it is the most important leaf for yield potential. A team from the University of Illinois and the International Rice Research Institute (IRRI) found that some flag leaves of different varieties of rice transform light and carbon dioxide into carbohydrates better than others. This finding could potentially open new opportunities for breeding higher yielding rice varieties. 

An international effort called Realizing Increased Photosynthetic Efficiency (RIPE) aims to transform crops' ability to turn sunlight and carbon dioxide into higher yields. To achieve this, scientists are analyzing thousands of plants to find out what tweaks to the plant's structure or its cellular machinery could increase production.

Crops grow dense canopies that consist of several layers of leaves--the upper layers with younger sun leaves and the lower layers with older shaded leaves that may have difficulty intercepting sunlight trickling down from the top layers.

The crops we grow in the field often form dense canopies with many overlapping leaves, such that young “sun leaves” at the top of the canopy are exposed to full sunlight with older “shade leaves” at the bottom. In order to maximize photosynthesis, resource-use efficiency, and yield, sun leaves typically maximize photosynthetic efficiency at high light, while shade leaves maximize efficiency at low light. 

Rice is a direct source of calories for more people than any other crop and serves as the main staple for 560 million chronically hungry people in Asia. With over 120,000 varieties of cultivated rice (Oryza sativa) across the globe, there is a wealth of natural diversity to be mined by plant scientists to increase yields.

Komorebi is a Japanese word that describes how light filters through leaves—creating shifting, dappled “sunflecks” that illustrate plants’ ever-changing light environment. Crops harness light energy to fix carbon dioxide into food via photosynthesis.

An international team is using advanced tools to develop crops that give farmers more options for sustainably producing more food on less land. To do this, thousands of plant prototypes must be carefully analyzed to figure out which genetic tweaks work best. In a special issue of the journal Remote Sensing of Environment, scientists have shown a new technology can more quickly scan an entire field of plants to capture improvements in their natural capacity to harvest energy from the sun.

One of the most significant challenges of the 21st Century is how to sustainably feed a growing and more affluent global population with less water and fertilizers on shrinking acreage, despite stagnating yields, threats of pests and disease, and a changing climate.

Plants convert sunlight into energy through photosynthesis; however, most crops on the planet are plagued by a photosynthetic glitch, and to deal with it, evolved an energy-expensive process called photorespiration that drastically suppresses their yield potential. Today, researchers from the University of Illinois and U.S. Department of Agriculture Agricultural Research Service report in the journal Science that crops engineered with a photorespiratory shortcut are 40 percent more productive in real-world agronomic conditions.

This week, families across the U.S. will gather around Thanksgiving tables in a traditional celebration of the season’s bounty. By improving how key crops transform sunlight into yield, Realizing Increased Photosynthetic Efficiency (RIPE) will one day help farmers put food on more tables worldwide, especially where it is needed most.