Smart plants are for real

October 2016

Ripe barley: Photo Creative Commons

We tend to view plants as having 'characteristics' rather than 'behaviours'. The latter suggests senses, reactions and communication at a level impossible without a nervous system.

Biotech scientists seem to view plants as lego-like structures into which they can slot characteristics of their choice, even animal ones. Belief in their ability to custom-build plant life is such that testing the whole-picture reality of what they've created has never been big on the GM agenda.

Plants, however, aren't simple bystanders in their environment, or passive sugar factories running on solar power. They're far smarter than we think.

Plant scientists have discovered at least 20 different senses with which plants monitor and respond to their environmental conditions. These include a whole spectrum of sounds and motions, humidity, load, gravity, ice and electro-magnetic fields. Moreover, plants can learn the difference between an apparent physical threat which they can ignore, and a real one to which they must react.

They're certainly capable of detecting what's going on around them even at a distance, protecting themselves, orchestrating their nutrients and water supplies, and communicating with microbes, animals and each other.

For example ...

Roots don't flounder around randomly. They grow purposefully towards nutrients and water, and start growing around obstacles before reaching them.

Making themselves herbivore-unfriendly is a common plant-trick. There are hundreds of species which coat themselves in unpalatable grit. Sometimes they don't bother, however, unless they know the risk is there. Thorns and stings and spikey leaves grow thickest in vulnerable parts of the plant. Science tells us that plants which hear munching caterpillars make themselves taste bad, and plants which are touched generate substances to give unwary herbivores a stomach-ache.

Plants don't only protect themselves. The huge network of soil fungi which connects their roots, or chemical signals in the air, form a telegraph system for warning other plants of imminent attack. These signals can also muster the helping hand of predators to beat off the enemy.soil

Gathering soil microbial life around their roots to nourish and protect themselves may be ubiquitous is plant-life. Woodland soil fungi helpfully channel nutrients from seasonal high-nutrient trees to seasonal low-nutrient trees.

It may be comforting to those of you who talk to your plants or play them music to know that science agrees they can hear and respond to sound.

Music has been shown to wake up seeds, and farmers wise in the ancient knowledge of India chant to their crops to promote healthy growth. Classical music and Indian raga accelerate plant growth rate and increase their final size. Young corn roots grow towards a continuous sound, especially at certain frequencies.

Communication with humans in other ways has been experimentally demonstrated. Healing energy (which has it origins in India) channelled through the hands inspires seeds to start growing. Bare-foot dancing ancient Indian-style made several plant species flower earlier.

Researchers have even discovered that plants recognise their close kin, reacting differently to plants with the same parents than to non-siblings.

How do plants achieve all this?

So far, the evidence is pointing to the millions of root tips in every root system as the centre of plant intelligence. The jury's out on how they sense and react, but plants do have a system for sending electrical signals and do produce substances akin to animal neurotransmitters. Theories of plant 'perception' include proteins in the cell membranes which are altered by external factors.

OUR COMMENT

Does all this suggest that the Bt crops which soil fungi don't like (see FUNGI DON'T LIKE Bt CROPS - September 2016) actually have 'brain-damaged' roots? And what might all that unnatural GM protein do to a delicate protein-based plant sensory-system?

Sadly, the vast majority of today's plant scientists are molecular biologists whose sole expertise is DNA and isolated biochemical pathways. The best they seem to be able to come up with to use this exciting infant knowledge of plant senses is to genetically transform crops to make them respond to sounds that would be useful to agriculture.

Perhaps if we studied them more closely and bred plants for greater intelligence, we'd achieve healthier crops and sustainable yields.

If you want to know more about plant intelligence, check out Peter Wohlleben's The Hidden Life of Trees, or Stefano Mancuso and Alessandra Viola's Brilliant Green: the surprising history and science of plant intelligence.

SOURCES:

• Jeremy Hance, Are plants intelligent? New book says yes, Guardian 4.08.15
• Simon Worrall, There Is Such a Thing as Plant Intelligence, National Geographic News, 21.02.16
• The Effect of Music on Plants, www.dengarden.com, 29.08.16
• Katherine Creath and Gary E. Schwartz, 2004, Measuring the Effects of Music, Noise, and Healing Energy Using a Seed Germination Bioassay, The Journal of Alternative Medicine, 10:1
• Dr. Mercola, Plants Are Smarter Than You Think, www.mercola.com, 26.03.16
• Richard Brooks, Beleaf it or not, trees chat to family and friends on the wood-wide web, Sunday Times 11.09.16
• Bruce Fritz, New research on plant intelligence may forever change how you think about plants, www.pri.org, 10.01.14