Avicennia have the highest salt tolerance of mangrove trees.
They do not exclude salts at the root level. In fact, their sap is
salty, at about one-tenth that of sea water. Instead, they secrete
excess salt on their leaves through special pores, to be removed by
rain or wind. Sometimes, the salt can be seen as a white crystalline
layer on the upper surface of the leaf.
To avoid suffocation in the oxygen poor (anaerobic) mud, they have
pencil-like pneumatophores. These stick out at regular intervals from
long shallow underground cable roots that spread out from the trunk
to stabilise the tree.
and wetland wildlife at
Sungei Buloh Nature Park
features: Grows to 25m.
Roots: pencil-like pneumatophores
emerge above ground from long shallow underground roots.
Flowers: Small, yellow,
several together, forming a cross-shaped inflorescence.
Avicenniaceae. World 8 mangrove species.
trees that are commonly seen in
Sungei Buloh include:
Api Api Putih (A.
Api Ludat (A. officinalis)
Api Api Bulu (A.
species regenerate branches easily from their trunk, it is possible
to harvest branches without hurting the tree and maintain mangroves for
such harvests (called coppicing). Avicennia is among the few used
in replanting mangroves to protect coastlines (the others are Sonneratia
is named after Ibn Sina (980-1037 AD), a Persian physician-philosopher
who gained fame by curing, at the tender age of 17, the King of Bukhhara
of an ailment that other physicians were unable to treat. As a reward,
he asked only for permission to use the King's library. Ibn Sina went
on to write an immense encyclopaedia of the medical knowledge of his
time, which remained in use for the next six centuries. The encyclopaedia
included his own insights into the causes and spread of diseases and
their treatment including tuberculosis, meningitis (he was the first
to describe it), gynaecological and diseases of childhood. He also
wrote an encyclopaedia of other scientific and philosophical knowledge
covering physics, mathematics, economics and politics. In this, he
also added his own insights into among others, the laws of physics,
astronomical measurements and mathematical verifications.
The tiny flowers are hermaphroditic; female flowers producing sterile
pollen while male flowers produce sterile ovules. Both types produce
lots of nectar and fragrance to attract insect pollinators. Avicennia
produces some of the best honey.
the seed does germinate on the mother tree, the growing shoot does
not penetrate the seed coat while the fruit is still on the tree (thus
this is called cryptovivipary). The shoot and roots only appear after
the fruit falls off. And these grow best in water of the right temperature
Role in the habitat: Being able to tolerate
saltwater, Avicennia are among the first mangrove trees to colonise
mud and sandbanks which are regularly flooded by seawater. Thus the trees
stabilise the shores, preventing erosion and allowing other plants to grow.
For more see mangrove trees.
- Peter K L Ng and
N Sivasothi, "A Guide to the Mangroves of Singapore I: The Ecosystem
and Plant Diversity", Singapore Science Centre, 1999 (p. 94-100:
description, habit, photo; p. 42 uses).
- Colin Field, "Journey among Mangroves", International
Society for Mangrove Ecosystems, 1995 (p. 70: medicinal use; p.116:
use in replanting mangroves)
- Michael Mastaller,
"Mangroves: The Forgotten Forest Between Land and Sea",
Tropical Press, 1997 (p. 93: as food; p: 102: other uses)