http://en.wikipedia.org/wiki/Aerenchyma http://en.wikipedia.org/wiki/Aerenchyma Wetland plants (like Mangroves) already transport substances from their leaves

http://en.wikipedia.org/wiki/Aerenchyma http://en.wikipedia.org/wiki/Aerenchyma Wetland plants (like Mangroves) already transport substances from their leaves to their roots.