New "Obvious" Reason for Epinasty

[socrtwo]

Epinasty, where the leaf stem purposefully grows putting the leaf at
45 or more degrees away from level with the ground, is an effect
caused by flooding in many plants and is mediated by Ethylene.

I think I have previously explained this response as one where the
leaf is putting it's guard cell openings more in the way of the
direction of wind, possibly increasing transpiration. Another
explanation given here is that the leaf comes to act like a water pump
with this epinasty effect. The response allows the leaf to act like a
pump handle and perhaps a new backflow valve is also developed by the
Ethylene released when flooding occurs.

I was discussing epinasty over lunch with my father. He suggested
another strong reason for Epinasty may simply be to allow the rain
water from the flood to flow off the leaf and not pool there.
Certainly the top part of a leave is protected by a wax, still
standing water pools many not desirable because of heat transfer and
disease fostering properties.