What is the Ultimate Source of Energy for Plants?
As it pertains to life, the energy cycle on planet Earth is a truly fascinating thing. All energy on our planet (literally all of it) traces its source back to the sun – there would be no life on this planet without the amazing engine of the sun. The sun allows plants to perform photosynthesis which produces glucose; this, in turn, is eaten by herbivorous animals and then by the carnivorous animals which eat them (nature can be cruel), until the cycle finally ends with decomposers like fungi and bacteria which destroy dead animal and plant matter. In this post, we’ll look at photosynthesis, the ultimate source of energy for plants, and how life on Earth could not exist without this fundamental process.
What is photosynthesis?
Photosynthesis is the process by which plants produce their own sugar. The term is a Greek one: photo comes from the Greek word for light (compare photo or photograph), and synthesis means “putting together”. As mentioned above, one of the ingredients they need to do this is solar energy, but it’s not the only one: they also require water, carbon dioxide, and chlorophyll (a chemical inside of plant cells) to create glucose. This is an amazing process if you really think about it, like most things on our planet.
What is the importance of photosynthesis?
Glucose is important for all life, not just plant life, so animals must directly or indirectly consume plants in order to get it – unfortunately we lack the ability to create our own energy just by absorbing solar radiation! As already pointed out, all forms of energy on the planet trace their origin back to the sun, and that includes the fossil fuels we use today such as natural gas, oil, and coal. They come from organic matter, which of course could not exist without the sun. It is believed that hundreds of millions of years ago, during what’s called the Carboniferous period, large trees and plants thrived in damp, swampy regions all over the planet. These plants would, of course, eventually die, and sink to the bottom of these areas where they would be turned into peat over a long period. This peat, in turn, was covered by sand and clay and other materials. Over millions of years the immense weight of all this sediment “squeezed” the water out of the peat, turning into oil, coal, and natural gas.
What is the relationship between photosynthesis and cellular respiration?
Photosynthesis doesn’t just create glucose. A byproduct of this process is the creation of oxygen, which is another vital element for animal life on Earth. Animal life must use oxygen for cellular respiration (the sort of animal analogue of photosynthesis), and one of the byproducts of this is carbon dioxide. We inhale oxygen and exhale carbon dioxide. Carbon dioxide, if you remember, is one of the ingredients required by plants for photosynthesis. This is a truly amazing, symbiotic process.
In which organelle does photosynthesis take place?
Photosynthesis takes place in the chloroplasts of plants, tiny microscopic “sugar factories” located in the cells of plants. Each cell contains around 40 to 50 chloroplasts. Within these chloroplasts is a chemical called chlorophyll which actually “traps” the light emitted by the sun. Overall, photosynthesis is much more complex than what they taught you in 10th-grade biology class! ATP provides the energy necessary for the process. Interestingly, chloroplasts have to absorb just the right frequency of visible light, which are red and blue wavelengths. They can’t use green wavelengths and reflect it; this is why plants look green to us! Light stimulates individual electrons of chloroplast molecules, which then transfer energy down the line like a falling stack of dominoes. This is, ultimately, how glucose is created. As Nobel Laureate Albert Szent-Gyorgyi aptly put it, the primary driver of all life on this planet (after the sun, of course) “is a little electric current, set up by the sunshine.”
Using Plants for Electricity
The fact that plants essentially produce electricity begs the question: could human society possibly harness this energy to power our modern lives? It may sound like a silly idea, but scientists and entrepreneurs have seriously considered this notion. The renewable energy industry is always changing, with new developments pretty much every day. Could this (literally) green energy help solve the impending threat of climate change and the dwindling of energy sources?
Plants could pack up to 200 millivolts of electricity!
Scientists from the Massachusetts Institute of Technology discovered that plants could pack up to 200 millivolts of electricity, showing that such a thing is certainly possible. Enter Plant-e, a company from the Netherlands which has shown that electricity generated by living plants can power mobile phones and Wi-Fi. Their systems have been used to power outdoor lighting in the Netherlands, and they even power their headquarters with this technology.
Plant-E’s systems are powered by electrons. During photosynthesis, the plant produces organic matter. Most of the organic matter is used by the plant, for instance, to grow, but some of it is unusable and is discarded into the soil beneath the plant. Microorganisms then devour this organic matter, thereby releasing electrons which power Plant-e’s systems. The company hopes especially to bring power to developing areas that don’t have electricity using large, wet areas like peat land, rice paddies, and deltas. They would install a tubular system in these areas which would go under the roots of the growing plants, without disturbing them at all.
As of the current date, their systems are still in development. Cost is an issue, as they can’t compete with wind or solar power for the time being, but Dr. David Strik, face of the company, hopes that costs will be brought down in the future. Most of the cost has to do with the initial installation, not maintenance, so Strik anticipates that the systems will be able to run for decades or even centuries with only occasional, above-ground maintenance. Another significant problem is that the amounts of energy produced are relatively small, which is why so far the company has only been able to power street lights and cell phones, for instance.
The future will be bright
On their website, Plant-e has concept art showing entire buildings being powered by plant life. It’s a fun idea to entertain, but most likely it will just be one form of clean energy among many. What the company has achieved in just a few short years is certainly impressive, but like all things, we’ll just have to wait and see what happens.