Maybe the people who are growing plants in monoculture and force-feed them with chemical fertilisers are the crazy ones, not the people talking to their plants. After all, plants actually have a social life. They recognise and support their siblings. They actively talk to all the plants around them. They are even able to actively communicate with animals and insects around them using fragrance signals. New research shows that plants even have long distance internal communication that function like nerves in animals, sending information via electrical impulses. Some research even suggest that plants can hear sounds and interpret them. And as outlandish as it may sound, they even have a memory and are able to pass that memory down to the next generation.
In this post about the fascinating life of plants, I will talk about the plant's fantastic root system.
Let me start of with some baffling facts about roots. Take for example to root system of a single rye plant. The plant will grow for about 4 months before we harvest it. In those 4 months, she will grow 13 815 672 roots that have a total length of 10 620 kilometers - that makes 89 kilometers of root growth per day. More than the average Swiss person drives every day! The total surface area of those roots will be 639 meters square - or about 8 average sized apartments.
In his TED Talk, Stefano Mancuso tells us how the tips of roots actually have an area that acts like the brain of lower animals. And that is not a metaphor. The cells actually exchange information and make collective decisions using the same signals like the neurons in our brain. And while each root apex only has as few hundred "neuron" cells, we know that all the 13.8 million roots talk to each other. The roots of a plant as a collective can be viewed like a bee hive. The collective intelligence of bees far surpasses that of a single bee. Bees have about 1 million neurons each, giving a whole bee hive of 100 000 bees a total brain capacity of 100 million neurons - that pales in comparison to the rye plant's total of 3 billion neurons.
Plant roots do not only communicate with one another, but live in a very close symbiosis with these root like fungi called mycorrhizae. The amount of mycorrhizae roots even far surpasses the amount of plant roots. None of this will ever be seen above the surface, leaving humans oblivious of this amazing symbiosis.
The mycorrhizae are amazing organisms that are able to break down all dead organic matter and make their nutrients available to the living plants. These mycorrhizae are even able to slowly break up stones and unlock their nutrients as well. In exchange, plants give the mycorrhizae energy in the form of sugar that the plant created through photosynthesis.
An experiment by a research team lead by Andreas Wiemken at the University of Basel demonstrates just how complex and fascinating these relationships can be: The researchers grew next to each other a millet and a flax plant in two different pots. In one of the pots they added mycorrhizae fungi, in the other they did nothing. In both pots the two plants were separated by an extremely fine nylon mesh that could only be penetrated by the mycorrhizae, but not the plant roots.
In the pot with the mycorrhizae, the flax plant would grow almost twice as fast as without the mycorrhizae, while the millet was mostly unaffected. The research team could prove that eighty percent of the sugar eaten by the mycorrhizae was produced by the millet. Thus, it was surprising that the flax plant was the one receiving more than 80 percent of the nutrients (phosphate and nitrogen) from the mycorrhizae. For the millet this was pretty much a zero sum business: giving up a lot of energy, but also receiving some vital nutrients. While at the same time it was unwittingly supporting the growth of the flax plant by feeding the mycorrhizae. The flax plant was of course a huge beneficiary.
Another fascinating example of plant symbiosis with mycorrhizae was demonstrated by a research team around Rusty Rodriguez at the University of Washington in Seattle. Rodriguez examined a rare grass that is able to survive 70 degrees Celcius around the hot springs of the Yellowstone National Park. He found that the grass has a fungus living inside it. When he removed the fungus, the grass could not take the heat any more and died immediately.
Rodriguez went on to isolate the fungus and inoculate regular wheat seeds with it. Wheat can normally not tolerate water that is warmer than 38 degrees Celcius. With the fungus living inside it, the wheat plant could also take water temperatures of up to 70 degrees Celcius. On top of that, the wheat plant only needed half the water to grow.
Another experiment showed that when the mycorrhizae of the salt loving marram grass were sprayed on regular rice seeds, that rice could also thrive in salty conditions. The rice even grew five times faster and needed only half the water!
All this research gives me hope that people will come to appreciate just how complex and wonderful plants are. We have clearly underestimated them. We have come to view them as these simple input-output biological machines. Yet, it becomes clear that plants are much more than that. Plants understand and interact with their environment. They they have memory that they can pass on to the next generation. And they even demonstrate a situational awareness and actively make decisions accordingly. These are all attributes that we usually do not give plants credit for and would normally only associate with large animals.