I was just wondering what makes a pepper plant grow one straight branch vs growing a straight branch and many different branches on the side of it? Pictures for reference:
At each tip, plants have an apical meristem, a collection of stem cells that divide to produce new cells that they leave behind to form the shoot they’re currently growing. At every leaf, they also leave behind another meristem that is capable of doing the same thing. However, the primary meristem also produces auxins, plant hormones that are transported down the shoot, inhibiting the activity of the other apical meristems left behind at each leaf. This is called apical dominance. When the primary apical meristem goes missing – either because it’s taken off the plant by pruning, eating, whatever, or because the plant has grown so much that the auxin concentration at the lower nodes is no longer sufficient for repression, the other meristems become active and start growing new branches.
Peppers have a few interesting phenotypes leading to various growth patterns: for example, Blood Ghosts and some other Pimenta de Neyde crosses produce a lot of auxin, leading to very strong apical dominance and tall, narrow growth. Pruning them has little effect because the topmost remaining meristems will take over dominance right away. At the other end of the spectrum would be Habanero Dulce, which starts growing side shoots before even splitting the main stem at the twelfth node. As a result, it grows very bushy.
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Apical dominance.
At each tip, plants have an apical meristem, a collection of stem cells that divide to produce new cells that they leave behind to form the shoot they’re currently growing. At every leaf, they also leave behind another meristem that is capable of doing the same thing. However, the primary meristem also produces auxins, plant hormones that are transported down the shoot, inhibiting the activity of the other apical meristems left behind at each leaf. This is called apical dominance. When the primary apical meristem goes missing – either because it’s taken off the plant by pruning, eating, whatever, or because the plant has grown so much that the auxin concentration at the lower nodes is no longer sufficient for repression, the other meristems become active and start growing new branches.
Peppers have a few interesting phenotypes leading to various growth patterns: for example, Blood Ghosts and some other Pimenta de Neyde crosses produce a lot of auxin, leading to very strong apical dominance and tall, narrow growth. Pruning them has little effect because the topmost remaining meristems will take over dominance right away. At the other end of the spectrum would be Habanero Dulce, which starts growing side shoots before even splitting the main stem at the twelfth node. As a result, it grows very bushy.