Which of the following is not an action of ethylene?
1. Induces leaf abscission
2. Inhibits root hair growth - decreasing the efficiency of water and mineral absorption
3. Induces the growth of adventitious roots during flooding
4. Stimulates epinasty - leaf petiole grows out, leaf hangs down and curls into itself
Enhanced root hair production, which increases the root surface area for nurient uptake, is a typical adaptive response of plants to photosphate (pi) starvation.