Why plants are green

The researchers' model borrows ideas from the science of complex networks, a field of study that explores efficient operation in cellphone networks, brains, and the power grid.

The model describes a simple network that is able to input light of two different colors, yet output a steady rate of solar power. This unusual choice of only two inputs has remarkable consequences. Gabor first began thinking about photosynthesis research more than a decade ago, when he was a doctoral student at Cornell University. He wondered why plants rejected green light, the most intense solar light. Over the years, he worked with physicists and biologists worldwide to learn more about statistical methods and the quantum biology of photosynthesis.

Richard Cogdell, a botanist at the University of Glasgow in the United Kingdom and a coauthor on the research paper, encouraged Gabor to extend the model to include a wider range of photosynthetic organisms that grow in environments where the incident solar spectrum is very different. Coauthor Rienk van Grondelle, an influential experimental physicist at Vrije Universiteit Amsterdam in the Netherlands who works on the primary physical processes of photosynthesis, said the team found the absorption spectra of certain photosynthetic systems select certain spectral excitation regions that cancel the noise and maximize the energy stored.

Gabor explained that plants and other photosynthetic organisms have a wide variety of tactics to prevent damage due to overexposure to the sun, ranging from molecular mechanisms of energy release to physical movement of the leaf to track the sun. Plants have even developed effective protection against UV light, just as in sunscreen. This is remarkably rare. If our model holds up to continued experiments, we may find even more agreement between theory and observations, giving rich insight into the inner workings of nature.

That process takes place in specific compartments within cells called chloroplasts and is split into two stages;. During these reactions, CO 2 dissolves in the stroma and is used in the light-independent reactions.

This gas is used in a series of reactions which results in the production of sugars. Sugar molecules are then used by the plant as food in a similar way to humans, with excess sugars stored as starch, ready to be used later, much like fat storage in mammals. Therefore, the red end of the light spectrum excites the electrons in the leaves of the plants, and the light reflected or unused is made up of more of wavelengths of the complementary or opposite colour, green.

The unused green light is reflected from the leaf and we see that light. The chemical reactions of photosynthesis turn carbon dioxide from the air into sugars to feed the plant, and as a by-product the plant produces oxygen. The technique first used by NASA to grow crops in space uses extended day-length, enhanced LED lighting and controlled temperatures to promote rapid growth of crops.

It speeds up the breeding cycle of plants: for example, six generations of wheat can be grown per year, compared to two generations using traditional breeding methods. By shortening breeding cycles, the method allows scientists and plant breeders to fast-track genetic improvements such as yield gain, disease resistance and climate resilience in a range of crops such as wheat, barley, oilseed rape and pea.

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Text on this page is printable and can be used according to our Terms of Service. Any interactives on this page can only be played while you are visiting our website. You cannot download interactives. Marine ecosystems contain a diverse array of living organisms and abiotic processes. From massive marine mammals like whales to the tiny krill that form the bottom of the food chain, all life in the ocean is interconnected.

While the ocean seems vast and unending, it is, in fact, finite; as the climate continues to change, we are learning more about those limits. Explore these resources to teach students about marine organisms, their relationship with one another, and with their environment. Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar.

Plants are green because the small amount of light they reflect is that color. But that seems unsatisfyingly wasteful, because most of the energy that the sun radiates is in the green part of the spectrum. Recently, however, in the pages of Science , scientists finally provided a more complete answer. They built a model to explain why plants' photosynthetic machinery wastes green light.

What they did not expect was that their model would also explain the colors of other photosynthetic forms of life too. Their findings point to an evolutionary principle governing light-harvesting organisms that might apply throughout the universe.

They also offer a lesson that—at least sometimes—evolution cares less about making biological systems efficient than about keeping them stable. The mystery of the color of plants is one that Nathaniel Gabor, a physicist at the University of California, Riverside, stumbled into years ago while completing his doctorate.