February 25, 2022 2 min read
One interesting example of this is that plant roots grow towards the sound of water.
We know plants are hydrotropic, which allows roots to actively grow towards necessary water sources. We would assume that root systems are responding to the presence of moisture. But what about instances where there is no moisture in the soil? Roots have been known to burst sealed pipes, wrapping around them until they crack. In these cases the moisture isn’t in the soil until after the roots have already grown towards it, weakened the pipes and created the leak. If the pipes are sealed and there is no water in the soil, how do the roots ‘know’ which way to grow?
Scientists have examined this in the lab with a pot that looks like an upside-down Y. This limits the plant and gives the roots two distinct directions to grow.
If roots grew in a random manner, half would go down to the right, and the other to the left.
Scientists placed a water source was placed nearby, outside of the pot, so no moisture could be detected within the soil. Just a few days later the roots were observed overwhelmingly growing in the direction that was closest to the water source.
The next step was to set up their experiment again, this time with a speaker playing a recording of the sound of water. In the other direction, another speaker was placed as a control, playing nothing. Again the majority of the roots grew towards the sound of the water.
Plants have neither ears, nor a brain with which to ‘hear’ like we do, nor process sound in the same way, and yet they have this amazing ability to sense the presence of water.