Maybe also to inhibit growth when exposed to a saline environment?

If this were recreated in Blender’s geo nodes these functions would be relatively easy to add using the raycast node.

While a plant growing in shade might grow slower than a plant growing in sunlight, a part of a plant growing in shade will grow faster than the parts growing in sunlight (mechanically, this is done using auxin plant hormones[0]). This is how a plant is able to "chase" sunlight. Picture a flower growing vertically with one half shaded, the other half sunned. If the sunny side grew faster, it would become longer than the shady side, causing it to curve into the shade, potentially killing the plant. Instead, the shady side "pushes" the plant into the sun.

[0] https://en.wikipedia.org/wiki/Auxin