Wiktionary
straightens
vb. (en-third-person singular of: straighten)
Usage examples of "straightens".
As soon as the pods begin to swell, the peduncles increase much in length and slowly curve downwards, but the short, upper, hooked part straightens itself.
Afterwards this portion straightens itself, and the cotyledons then free themselves from the seedcoats.
The main petiole is curved slightly downwards during the day, but straightens itself at night.
Before the cotyledons are fully expanded and have diverged, the hypocotyl generally straightens itself by increased growth along the concave side, thus reversing the process which caused the arching.