The roots of the mangrove plants

Our experience at Laborador park was memorable, as it was both an outdoor science lesson and an eye-opener for us.  Together with a tour guide, we walked along a trail leading us up a creek – from where the creek met the salty sea, up to where the mixture of salty seawater and fresh water from the mountains beside was more equal.  Although there were numerous interesting “survival features” of the plants we saw there, one of them clearly stood out even more than the rest. 

Firstly, the roots of the mangrove plants.  I’m sure everyone knows about these, but why are they needed in the first place?  Well, this is because, as mentioned earlier, the mangrove swamps’ water is salty, especially near the ocean.  In fact, this factor alone would cause a normal plant to die in less than a week!  What mangrove plants do is to keep the salt out, through means such as preventing salt from entering their roots and secreting salt out through their leaves.  However, the mangroves’ roots also have to cope with two other stresses – rapid tide level variations, which are enhanced upstream, as well as the lack of oxygen in the soil. 

Pencil Roots

Prop Roots

  To adapt to this, mangrove plants have developed prop roots and pencil roots. As shown above, prop roots are like a normal plant’s roots that have been pulled above ground, and pencil roots like sticks sticking out of the ground vertically.  Prop roots focus on keeping the plant sturdy amidst water movements, although stilt roots may later grow down when the plant gets older.  Pencil roots, on the other hand, focus on obtaining oxygen from the air, but the circles in which they grow still give a plant enough support.