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Api Api (Malay)
Avicennia spp

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.
Mangrove and wetland wildlife at
Sungei Buloh Nature Park

Main 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.

Fruits: Small.

Classification: Family Avicenniaceae. World 8 mangrove species.

pneumatophores
Avicennia trees that are commonly seen in
Sungei Buloh include:
Api Api Putih (A. alba)
Api Api Ludat (A. officinalis)
Api Api Bulu (A. rhumphiana)
Avicennia 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.

germinating seedlingsWhile 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 and salinity.
Because Avicennia 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 and Rhizophora).

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.


LINKS
REFERENCES
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  • 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)
 
By Ria Tan, 2001