I learned this today. Bamboo can grow so fast because it doesn’t need leaves until it is fully grown, it grows with a constant diameter, and it can stretch its cells.
Bamboo is actually a grass, and it is one of the fastest growing plants in the world. Bamboo is generally fast growing, but some species grow much faster than others. The Chinese moso bamboo can grow up to 90 cm in a day. That is about 4cm an hour and about 1mm every 90 seconds. You can literally watch bamboo growing.
Bamboo has evolved to grow fast because it grows in a tightly packed area. The bamboo is so close together that the light cannot penetrate far down. The bamboo needs to get its leaves above the bamboo stalks and towards the sun as fast as possible so that it can photosynthesize.
There are three things that help bamboo grow so fast. The first is that it doesn’t need leaves until it is fully grown. There would be no point for the bamboo to have leaves further down its stalk because there is no sunlight there. A plant or a tree has to use energy to grow leaves and there has to be a balance of energy. The tree must be able to recoup the energy it used to grow the leaf through photosynthesis, or there is no reason to grow a leaf. The energy that the bamboo saves by not growing leaves can be redirected into growing taller.
The second thing is that bamboo grows with a constant diameter. Most trees are extremely heavy, and they have to have a wide base in order to support the weight of their foliage. They need to spread their branches out as far as possible to get as much sunlight on their leaves as they can. In order to be able to support this weight, their trunks have to be strong and thick. Every time they grow taller, they also grow another layer on their trunks. This is what makes the rings of a tree. It also uses up energy. Bamboo doesn’t do this. They don’t have a mass of foliage that needs supporting, so they can use all of that energy to concentrate on growing quickly.
The third thing is probably the most important of all. Bamboo doesn’t need to grow a lot of new cells to grow taller. Bamboo buds have all of the cells in them that the stalk will ever need. A fully grown bamboo stalk is separated into segments about a meter apart (depending on the type of bamboo). When the bamboo is a bud, it already has all of these segments and all of the cells that go between them, but they are compressed. The bamboo grows by pumping these cells full of water and expanding them. It expands telescopically.
Bamboo can do this because of its root system. An oak tree, for example, is a stand-alone tree. It has to make its own energy with its own leaves, and it stores all of that energy in its root system. A bamboo stalk is not a standalone tree. One bamboo stalk is a branch from a much larger plant called a rhizome system. The rhizome is the main stem of the plant, and it grows horizontally under the ground. The bamboo stalks are shoots that grow up from it. A lot of grasses are rhizomes. All of the sugars and water are stored in the underground root system and the bamboo plant uses this to push up a new stalk.
When bamboo has finished growing, it is still quite soft and watery. When it has reached its full height, it grows branches and leaves out from the top and starts to harden. It takes about two years to become fully solid.
Bamboo cultivation is a huge industry worth billions of dollars a year. Bamboo is far more economical and environmentally friendly than wood from trees because it replenishes itself so quickly. The bamboo is usually cut down when it has reached its greatest strength and has the lowest water and sugar content. This is usually at about five years old. Once cut down, more stalks will grow. Bamboo grows in the same way as the grass in your garden and replenishes itself.
Bamboo is also useful because it can grow on infertile soil, repairing the soil. This happens because the leaves fall off the bamboo and add nutrients to the soil when they decompose. Bamboo also absorbs more than four times more carbon dioxide than other plants.
So, bamboo can grow so quickly because it doesn’t need to waste energy growing leaves or making itself thicker. It also only has to fill its cells with water to grow. Bamboo is a grass and the stalks we see above the ground are shoots coming off a mass of underground roots. And this is what I learned today.
Photo by Martin Péchy from Pexels
Sources:
https://www.quora.com/How-can-bamboo-grow-so-fast
https://www.science-sparks.com/why-does-bamboo-grow-so-fast/
https://www.sciencedaily.com/releases/2021/02/210201090829.htm
https://en.wikipedia.org/wiki/Bamboo
https://en.wikipedia.org/wiki/Rhizome
https://www.botany.one/2017/11/bamboosting-growth-bamboo-grow-fast/
https://www.ambientbp.com/blog/the-incredible-bamboo-plant
https://www.sciencefocus.com/nature/speed-bamboo-plant-grow/