eli5: How do plants “know” which direction to grow in (to catch most light)?

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I recently put a new plant by my window, and within a week it had grown “lopsided”. The leaves nearer the window were much bigger and all the leaves were angled to face the window.
It makes sense since all the light is coming from one direction, but how did it know that?
Is there a central “brain” which tells the leaves to grow that way? Or is it something about the leaves themselves that makes them do that?

In: Biology

2 Answers

Anonymous 0 Comments

The side of the stem which gets less light grows more, which makes the stem bend. The phenomenon has a scientific name, but I can’t recall what it is.

Anonymous 0 Comments

The explain it like I’m 5 version: Collectively similar to how people move to large cities as compared to small rural villages, (for more resources, such as food, jobs, and fun !) Parts of plants will gravitate more towards areas that experience more photosynthesis (sunlight areas), because that means more energy, and more survival. it’s a Plant party there.