While being known as someone with a “green thumb” has always been something plan-lovers have aspired to be known as, a new discovery could potentially put an end to the term as we know it. Scientists already know that plants are highly sensitive to touch of any kind, and even have a word for this phenomenon – thigmomorphogenesis. However, most of the time, the effect is not visible. Or not immediately visible, art least. Researchers from La Trobe University published a report in The Plant Journal, stating that they have now found that plants are highly sensitive to touch, and repeated touching could significantly affect their growth in a negative way.
La Trobe researchers, Drs. Jim Whelan and Yan Wang, revealed the results of their study, which observed the responses of Arabidopsis to various test touch stimuli. Whelan said that even the slightest touch turns on a major genetic defence response, which when repeated, slows down plant growth. “Within 30 minutes of being touched, 10 per cent of the plant’s genome is altered…This involves a huge expenditure of energy which is taken away from plant growth. If the touching is repeated, then plant growth is reduced by up to 30 percent,” Whelan explained.
Wang further explained that the reason behind the strong reaction of plants to touch is yet to be revealed, their research findings have led to a deeper understanding of the genetic defence mechanisms involved particularly in opening up new approaches to reducing sensitivity and optimising their growth.
“The lightest touch from a human, animal, insect, or even plants touching each other in the wind, triggers a huge gene response in the plant,” Professor Whelan said. “Within 30 minutes of being touched, 10 per cent of the plant’s genome is altered. This involves a huge expenditure of energy which is taken away from plant growth. If the touching is repeated, then plant growth is reduced by up to 30 per cent.” he continued.
La Trobe co-author, Dr Yan Wang has stated on his published post that while researchers don’t completely know why plants are reacting so strongly to our touch, the new research discovery have led to a new and deeper understanding of the genetic defence mechanisms that plants posses, as well as how they’re opening up new approaches to reducing sensitivity and optimising growth.
“We know that when an insect lands on a plant, genes are activated preparing the plant to defend itself against being eaten,” Dr Yang said. “However, insects are also beneficial, so how do plants distinguish between friend and foe? “Likewise, when plants grow so close together that they touch one another, the retarded growth defence response may optimise access to sunlight. He then continues, “So, for optimal growth, the density of planting can be matched with resource input.”
Professor Whelan has also stated that with this new and deeper understanding of the genetic mechanisms involved, it may be possible to identify and breed a variety of new plant varieties which are less sensitive to our own touch, while still retaining their sensitivity to other factors such as the cold and heat that comes with a variety of harsh climate based locations.
According to the scientists on board with the study, the next steps in the research will be to test touch response as a whole in specific crop species and to look at the potential consequences of breeding plants which are less touch sensitive and how they’d impact the environment.
“As we don’t understand why plants display such a strong defence response to touch, if we are to breed less touch-sensitive varieties, we need to first understand what some of the consequences might be,” Professor Whelan said. “For example, could touch-resistant plants be more susceptible to disease because a crucial defence mechanism has been removed?” He continued.