Perspiring Trees: The White Mangrove
Laguncularia racemosa is the scientific name of the White mangrove. This mangrove tree grows on land and is found in tidal areas as well as around lagoons and ponds. But depending on the water level situation, White mangroves can also grow pneumatophores and prop roots like their distant relatives the Black and Red mangrove.
White mangroves also produce a fruit with a sapling inside. The fruit is small, dry, leathery and ribbed like a prune. And like the fruit of the Red and Black mangrove, these can also float for long periods before the sapling roots.
Typically, the White mangrove, like all mangroves, grows in poor, salty soil. Salty soils make land plants dry out. But the White mangrove is able to excrete or push out the salt from its system through hundreds of pores on its leaves. Salty water is excreted from the tiny pores. The water then evaporates or dries up and the salt is left behind on the leaf surface. This salt then gets washed off the leaf when it rains. The leaves are round at the base and the tip and smooth underneath. Also, they are thick with a leathery feel. The thickness and leathery-ness of the leaves help to keep moisture in the tree.
At the base of each leaf where the stem starts are two bumps called nectaries. Some scientists believe that these bumps secrete sugar. They think that the ants help to control harmful insects when these bumps attract ants. Other people think that the tree uses the nectaries like perspiration glands to get rid of the salt.
Which explanation do you think is the right one?
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