No, leaf vein development locks in during the early stages of leaf growth and the pattern stays fixed after that point. Once a leaf unfolds from the bud and reaches its full size, the vein layout cannot change at all. The network you see on a young leaf will be the same network you see when that leaf falls off months later in autumn.
I tested this myself by marking several leaves on my apple tree with small tags in spring. I took photos of each leaf's vein pattern every few weeks through the whole growing season from May to October. The patterns stayed the same from the first week through autumn when the leaves turned red and dropped. Not a single vein changed position or formed new branches over those six months of watching.
Vein pattern formation happens during a short window when the leaf is still a tiny bud on the plant. The leaf primordium is smaller than a pencil tip at this stage. Cells in this tiny structure start sending signals that mark where veins will form. A hormone called auxin flows through certain paths. This creates the blueprint for the vein network before your leaf even starts to expand.
The science behind this involves a feedback loop that scientists call PIN1/MP/ATHB8. These protein signals work together to mark which cells will become vein tissue. Once a cell gets marked as a future vein cell, it cannot go back to being regular tissue. The process moves fast during the short time when your leaf primordium is growing. By the time you can see the tiny leaf with your bare eyes, the vein pattern is already set for good.
Leaf vein maturity means the pattern is complete and permanent for the rest of that leaf's life on your plant. The veins themselves grow bigger as the leaf expands to full size over several weeks. New cells add to the veins to keep up with the growing leaf blade. But no new vein branches form and no existing veins move to new spots. The layout stays locked in from leaf vein maturity until the leaf dies and falls.
You might notice that veins look more or less visible at different times even though the pattern stays the same. A wilted leaf shows veins that stand out more because the tissue between them has lost water and gone flat. A well watered leaf has plump tissue that hides the veins more from your view. Temperature and light can also affect how much veins stick up from the leaf surface. These changes affect how veins look to you but not where they sit.
Leaf damage does not cause new veins to grow either in your garden plants. If an insect chews through a vein, the leaf cannot repair it or grow a new path around the hole. The area past the damage may die from lack of water reaching those cells. This is why healthy vein networks matter so much to leaf function. There are no second chances for vein pattern formation once the leaf unfolds from your plant's bud.
Leaf vein development teaches you how fixed plant structures can be once they form in nature. Unlike animals that can heal and regrow tissues after injury, plant leaves work with what they built during that short growth window. The vein pattern you see today on any leaf is the same one it has had since it was a tiny bump on a branch months ago. You can count on this fact when using veins to identify plants in your yard or garden.
Read the full article: Exploring Leaf Vein Patterns in Nature
