How do potatoes know which way to grow?

[Rocketron]

Gravity will give the roots a clue as to which way to go so there must be something in the seed that lets the stem know it's got to head in the opposite direction to the roots? Once the foliage breaks surface it will head to the light source.

So what happens if you germinate seeds in space in zero gravity? Poor plant will have stems and roots together? Or will it?

In a normal situation it could be gravity and darknesss for roots and the opposite way to gravitational pull plus light source for greenery?

My head hurts........I'm going for my brekkie!

Phototropism is the word you're looking for, I believe.

[Snadger]

Phototropism is the word you're looking for, I believe.

Or Gravitropism?Gravitropism - Wikipedia, the free encyclopedia

Either way my head still hurts!