Plants don’t die from lack of water. They die because in order to get carbon dioxide, they open their pores and let all of their water escape. The more carbon dioxide, the less they do this. Corn and other grasses have a special trick to minimize carbon loss: they grab the carbon at night and store it until the sun comes out when they can photosynthesize. This is why grasses grow fine in climates (like prairies and steppes) that don’t support other types of flowers and trees that can’t do this. (Palms are on the grass side of the family.)