positive geotropism

19 LETTERS · STARTS WITH P

positive geotropism is a valid 19-letter word worth 28 points in Scrabble and 33 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

P3O1S1I1T1I1V4E1G2E1O1T1R1O1P3I1S1M3

3 + 1 + 1 + 1 + 1 + 1 + 4 + 1 + 0 + 2 + 1 + 1 + 1 + 1 + 1 + 3 + 1 + 1 + 3 =28 PTS

DOUBLE WORD → 56TRIPLE WORD → 84

MEANING

What does positive geotropism mean?