Plant & zo
The science of plants and more
Not only do roots anker the plant to the ground, they also actively search for water and nutrients. In their search they come across a range of obstacles. Think about stones and other roots, but also more densely packed patches of soil. They grow gently around or through these.
During growth the tip of the root is its navigation system. With help of calcium signals and hormones it lets the rest of the root know where to go. Right down. Or maybe left, because there are more nutrients that way, in that case the tip gives the message: cells on the right site, stretch out more.
But how do they know they come across an obstacle, that is what researchers in America where asking. First, they looked at what happens when a root hits an obstacle. This causes mechanical pressure on the root tip. This pressure thus tells the root tip there is an obstacle.
The next question was, how does the plant translate this into a biological signal? In their search for the answer, researchers discovered that they do this with help of channels, called PIEZO, located in root tip cells. These doors between cells open when the root tip encounters pressure, letting through a calcium signal to the rest of the root.
PIEZO is important for growing through densely packed soil. Without PIEZO roots are growing less quick through hard ground. Therefore, PIEZO is part of the navigational system. When PIEZO opens, it tells the rest of the root: more force, we encounter hard ground.
Seyed A. R. Mousavi, Adrienne E. Dubin, Wei-Zheng Zeng, Adam M. Coombs, Khai Do, Darian A. Ghadiri, William T. Keenan, Chennan Ge, Yunde Zhao, Ardem Patapoutian (2021) PIEZO ion channel is required for root mechanotransduction in Arabidopsis thaliana. PNAS 118: e2102188118