Gone are the days of believing plants are just passive organisms. Earlier this year, researchers found that plants can communicate through little understood chemical mechanisms. Now scientists are even saying that plants can do something perhaps even more incredible: Control the weather. According to researchers at the Scottish Association for Marine Science and the University of Manchester, brown seaweed, kelp, has the ability to create cloudy days at the seaside. But why would plants want to alter weather patterns? Apparently, because cloudy days make the plants more comfortable.
When the sky is overcast kelp are comfortable when the tide goes out, since they are able to stay moist until it comes back. On a bright day however, they dry out. When they start getting dry the plants become stressed and begin releasing iodide. The iodide rises, causing clouds to form overhead, which in turns protects the kelp from unwelcome sunshine.
Kelp plays an important antipollution role in the removal of ozone close to the Earth’s surface. Frithjof Küpper, of the Scottish Association for Marine Science, who led the research, explains that the benefit is mutual. Iodide can neutralize ozone in the atmosphere and, as it rises, “these chemicals act as condensation nuclei around which clouds may form”. Hence we get a healthier atmosphere and the kelp also gets what it wants: Shade.
This discovery reveals just one more fascinating secret of the green kingdom, a kingdom that is just barely beginning to be understood by humans. For most of history scientists, and mankind in general, considered plants to be passive organisms just with no reason or means of communicating with one another. But research earlier this year also revealed that many plants actually ‘chat’ quite a bit over their own networks (which may also indicate that your aunt isn’t quite as crazy as you thought. You know, the one that talks to her petunias and expects an answer).
Researcher Josef Stuefer at the Radboud University Nijmegen found that one purpose for plants having their own “chat systems” is to warn each other, which has led scientists to conclude that plants are not nearly as boring as once supposed. In fact, many plants form internal communications networks and are able to exchange information efficiently. Herbal plants such as strawberry, clover, reed and ground elder naturally form networks. Individual plants remain connected with each other for a certain period of time by means of runners. These connections enable the plants to share information via internal channels in a manner very similar to computer networks. So what kind of things do plants tell each other?
Stuefer and his colleagues were the first to demonstrate that clover plants do indeed warn each other via these network links if enemies are nearby. For example, if one of the plants is attacked by caterpillars, it will warn the other members of the network via an internal signal. After receiving a warning, the other intact plants will strengthen their protective chemical and mechanical resistance so that they are less attractive for advancing caterpillars. This early warning system allows the plants to stay one step ahead of their enemies. Experimental research has revealed that this communication significantly limits the damage inflicted on the plants.
It is also known that plants have “family values”, with new research revealing they have the ability to recognize close relatives in order to help each other survive. The ability to tell family from strangers is well known in the animal kingdom, which allows us to cooperate and share resources. However, it is a relatively new concept that plants also possess the social skills of being able to recognize and communicate with relatives. Even plants that are not connected seem to have the ability, although scientists still have no clear idea how they do it.
Earlier this year, Susan Dudley and Amanda File of McMaster University in Ontario, Canada, demonstrated for the first time that plants can recognize their kin. Their research showed that though lacking cognition and memory, plants are nonetheless capable of relatively complex social interactions.
"Plants have this kind of hidden but complicated social life," Dudley notes.
Their study found plants from the same species of beach-dwelling wildflower, for example, grew aggressively alongside unrelated neighbors but were less competitive when they shared soil with their siblings. Some researchers speculate that plants must communicate through their roots, identifying themselves using tiny chemical signatures specific to each plant's family. But just how the plants determine which of their neighbors are siblings remains a mystery, Dudley admits. While learning and memory are important factors for kin recognition in animals, there obviously has to be an alternative explanation for plant recognition, she noted.
This research, along with other emerging plant studies, is revealing that our current concept of plants is probably a poor reflection of reality. "Scientists are eager to discover more about how plants communicate and interact with their environments."
Posted by Rebecca Sato.