How do plants grow their branches and leaves? What happens if the areas of growth become damaged? Does the plant just die? The answer is…adventitious buds!
How Do Plants Grow?
Like humans, plants generally grow up or out. Unlike humans, they can keep growing even when very old, and even regenerate when severely damaged!
The meristem refers to regions of a plant that makes undifferentiated cells, sort of like blank cells with no assigned job….yet. These cells, or meristematic tissue, are later activated for various uses, like being part of a leaf or stem or bark, helping the plant to grow.
Most of the growth from a plant comes from a specific meristem region called an apical meristem. This is the ‘apex’ or tip of the main ‘shoot’ or stem of the plant.
But what happens if the plant’s apical meristem gets damaged, say from an animal or a frost? Surprisingly, the plant doesn’t die, it has found a way to live on and make more of its kind. The plant’s answer to this issue is adventitious buds.
What Are Adventitious Buds?
The word adventitious, when used in biology and specifically botany, means anything that grows where it normally would not. So adventitious buds grow out of different places than the apical meristem. Such places could include but are not limited to leaves, shoots (stems), or even whole new plants via adventitious growth from the roots.
These buds can begin to grow at any particular point in the plant’s life, and can facilitate growth if the apical meristem gets harmed for some reason. Even stumps of trees can grow an entirely new tree by utilizing adventitious budding.
Adventitious budding can form if a new circumstance changes something in the plant’s situation. For example, think of the trunk of a tree that is shaded because of the tree next to it. If that neighboring tree falls, the first tree’s trunk is exposed to sunlight. The tree may create adventitious buds from its trunk to take advantage of the new light source.
We can also see adventitious buds takeover where pruning has taken place or where a tree loses a limb. Buds in that area can activate and begin growing entirely new branches, thus helping to save the tree. Horticulturists use this trait to their own whim, coercing the tree to grow in certain ways by manipulating adventitious bud growth, such as in Bonsai trees.
Some plants can create buds on their roots, even without damage to the apical meristem. The ‘creeping thistle’ gets it name from just this behavior. These buds form new shoots and essentially create a duplicate plant a little further away from the original.
A true tenacity of survival can be seen in redwoods trees. The stump is sold in small pieces that when placed in water, develop brand new roots and shoots.
Plants grow up and out. This occurs through the apical meristem which is a feature at the tip of the shoot or stem of the plant where meristematic tissue creates undifferentiated cells. These cells are later assigned a job, and multiply to grow the plant.
Sometimes the apical meristem can become damaged and then the plant cannot grow from it. It will then use adventitious buds which can grow out of areas of the plant not normally used for growing. The plant will sprout new buds that can carry on the growth of the plant.
You can see adventitious budding off of trunks, stumps, roots, or even used in aesthetic practices like Bonsai tree cultivation.