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Avicennia marina (Forssk.) Vierh.

Protologue
Denkschr. Kaiserl. Akad. Wiss., Math.-Naturwiss. Kl. 71: 435 (1907).
Family
Avicenniaceae (APG: Acanthaceae)
Chromosome number
2n = 36
Synonyms
Avicennia officinalis auct. non L.
Vernacular names
White mangrove, grey mangrove, olive mangrove (En). Palétuvier blanc (Fr). Mangue branco, mangue nero, salgueiro (Po). Mchu, mtsu, nsusi, nsuti (Sw).
Origin and geographic distribution
Avicennia marina is extremely widespread along the coasts of eastern Africa, islands of the Indian Ocean, tropical Asia, Australia, New Zealand and islands of the Pacific Ocean to Fiji. In tropical Africa it occurs from Egypt to South Africa, and in most islands of the Indian Ocean.
Uses
The wood is used for poles in house building, for boat construction, especially for the ribs, for furniture and handles, and to make beehives. The branches serve as stakes for fences. The wood is also used as firewood and for charcoal production; it is especially used for lime burning.
The bark has been used for tanning and for dyeing reddish and brownish colours. In Mozambique the bark of Avicennia marina was formerly utilized commercially for tanning, but the tannin content is rather low. The smoke of burning wood is considered very efficient as a mosquito repellent. The cotyledons of the seed are occasionally eaten, but may contain toxic compounds. The foliage serves as fodder for livestock. Leafy branches are used for making fish kraals. The tree is useful for preventing coastal erosion and as a windbreak. Honey bees collect nectar from the flowers.
The resin from the bark is used to treat snake bites and to remove the placenta after childbirth. In Madagascar a leaf decoction has been used as antidote after eating poisoned fish, whereas leaf and bark decoctions are applied against scabies. In traditional medicine in Australia, leaves, young shoots and bark are applied as an anodyne, and wood ash to treat skin complaints.
Properties
The wood is greyish to yellowish, with fine and even texture. It is heavy and durable, and the wood properties are comparable to those of Avicennia germinans (L.) L.
Several iridoid glucosides and flavonoids have been isolated from the aerial parts of Avicennia marina. Several naphthoquinone derivatives have been isolated from the twigs, and some of these (avicequinone A, avicequinone C, stenocarpoquinone B, avicennone D and avicennone E) showed strong antiproliferative and moderate cytotoxic activities as well as antibacterial effects.
The leaves contain 10.5% crude protein, 21.5% crude fibre, 3.5% ether extract and 21% ash. The in-vitro organic matter digestibility is 60.5%, indicating that the leaves can be used as a forage to meet maintenance requirements of camels. The bark contains 0.6–2.2% tannins.
Avicennia marina tolerates heavy metals in the soil very well. The roots may be employed as a biological indicator of environmental exposure to copper, lead and zinc.
Description
Evergreen shrub or small tree up to 10(–15) m tall; roots with many vertical breathing roots above soil level; bole usually low-branching, up to 40(–50) cm in diameter, sometimes with small prop roots; bark surface smooth to slightly fissured or flaky, brownish or yellowish green, inner bark greenish; crown dense and rounded; twigs fine-hairy, slightly angular. Leaves decussately opposite, simple and entire; stipules absent; petiole 0.5–1(–1.5) cm long; blade elliptical to ovate-elliptical or elliptical-lanceolate, 3–12 cm × 1.5–5 cm, cuneate at base, acute or acuminate at apex, leathery, minutely whitish hairy below, sometimes minutely pitted, pinnately veined with 8–15 pairs of lateral veins. Inflorescence an axillary or terminal head-like cyme, short-hairy. Flowers bisexual, regular, sessile, with 3 bracts up to 4 mm long at base; sepals 5, ovate to elliptical or nearly orbicular, 3.5–4 mm long, hairy outside; petals 4, fused halfway, 4.5–7 mm long, lobes ovate, hairy outside, yellow to orange, becoming blackish after flowering; stamens 4, inserted on corolla tube and alternating with corolla lobes, filaments very short; ovary superior, conical, c. 2.5 mm long, hairy in upper part, 1-celled, style c. 1 mm long, 2-lobed. Fruit a slightly asymmetrical, broadly ellipsoid to ovoid capsule 1–3 cm long, leathery, scaly hairy, yellowish green, dehiscing with 2 valves, 1-seeded. Seed compressed. Seedling with epigeal germination, viviparous; hypocotyl elongated; cotyledons thick and fleshy, folded; radicle usually glabrous, with short hairy collar.
Other botanical information
Avicennia comprises about 8 species and occurs in all tropical regions, locally extending into the subtropics; 2 species are found in tropical Africa. In the past Avicennia has been included in the family Verbenaceae, but it differs in wood and leaf anatomy and seedling and pollen morphology, and has been placed in a separate family: Avicenniaceae. In a recent molecular analysis it was nested within Acanthaceae.
Avicennia marina is variable over its large area of distribution, and 3 varieties (also considered as subspecies) have been distinguished. Only one of these (var. marina) occurs in tropical Africa. However, the varieties show much morphological overlap.
Anatomy
Wood-anatomical description (IAWA hardwood codes):
Growth rings: 2: growth ring boundaries indistinct or absent. Vessels: 5: wood diffuse-porous; (7: vessels in diagonal and/or radial pattern); (10: vessels in radial multiples of 4 or more common); 13: simple perforation plates; 22: intervessel pits alternate; (23: shape of alternate pits polygonal); 24: intervessel pits minute ( 4 μm); 30: vessel-ray pits with distinct borders; similar to intervessel pits in size and shape throughout the ray cell; 41: mean tangential diameter of vessel lumina 50–100 μm; 42: mean tangential diameter of vessel lumina 100–200 μm; 48: 20–40 vessels per square millimetre; 58: gums and other deposits in heartwood vessels. Tracheids and fibres: 61: fibres with simple to minutely bordered pits; 66: non-septate fibres present; 69: fibres thin- to thick-walled; 70: fibres very thick-walled. Axial parenchyma: 76: axial parenchyma diffuse; 78: axial parenchyma scanty paratracheal; 79: axial parenchyma vasicentric; (80: axial parenchyma aliform); (81: axial parenchyma lozenge-aliform); 91: two cells per parenchyma strand; 92: four (3–4) cells per parenchyma strand; 93: eight (5–8) cells per parenchyma strand. Rays: (97: ray width 1–3 cells); (98: larger rays commonly 4- to 10-seriate); 105: all ray cells upright and/or square; 109: rays with procumbent, square and upright cells mixed throughout the ray; 115: 4–12 rays per mm. Secretory elements and cambial variants: 133: included phloem, concentric. Mineral inclusions: (144: druses present); (145: druses in ray parenchyma cells); 152: crystals of other shapes (mostly small); 154: more than one crystal of about the same size per cell or chamber.
(P. Détienne & P.E. Gasson)
Growth and development
The leaves excrete excess salt through pores, and salt crystals are commonly present on the leaves. The minute hairs that cover the lower surface of the leaf play a role in the water balance, but more studies are still needed to understand the exact processes. In southern Africa trees flower from August to October, in Kenya in October–November. Individual flowers are open for 2–5 days. The flowers are protandrous, and this makes self-pollination unlikely, but pollination from flowers of the same plant is likely. Partial self-compatibility has been demonstrated by bagging flowers. The flowers attract short-tongued insects such as bees, which receive pollen on their abdomen while collecting nectar. After the stamens have turned black, the 2 lobes of the stigma expand, enabling pollination by insects that previously visited a flower in the male stage. Fruits take 2–3 months to mature in regions around the equator, but up to 10 months in temperate climates such as in New Zealand. However, in general the whole process from bud initiation to abscission of mature fruit is completed within a year. In south-eastern Australia only 3% of floral buds developed into viable seeds, with insect attacks on developing fruits as the main cause of mortality. The average annual supply of viable seeds per tree is approximately 250. The seeds start germinating while still attached to the tree, but the embryo stays within the fruit until fruit fall. Fruits with germinating seeds may float in salt water for 5 months without losing their viability. Most of these strand within 1 km of the mother tree, and very few were observed to disperse more than 10 km.
Ecology
Avicennia marina occurs in mangrove vegetation, usually at the landward side of the mangrove, where it is often dominant or occurs even in pure stands. It has a wide physiological tolerance to salinity, being able to survive in fresh stagnant water as well as in seasonally dry conditions with very high salinity; it also has a wide tolerance to intertidal position and to temperature. It can be found across the entire intertidal profile above mean sea level, and occupies offshore reef lagoons as well as sandy or rocky sheltered embayments. In Kenya Avicennia marina typically displays a double zonation pattern, occurring on the coastal edge of mangroves, often as a tree up to 15 m tall, as well as on the inland side, often as a shrub. In South Africa tree height frequently decreases from up to 10 m in the fringe zone to less than 1.5 m inland at a slightly higher elevation, as a result of hydro-edaphic factors contributing to high soil salinities, low water potentials, water stress and ion imbalance within tissues in the inland sites. Avicennia marina is often a pioneer in sandy habitats, but may also invade mud flats. It tolerates soils with a pH of 6 to 8.5. It is intolerant of shade. Avicennia marina occurs in regions with a mean annual temperature of 17–26°C and mean annual rainfall of (200–)1000–4500 mm.
Propagation and planting
Natural regeneration is often abundant, and wildlings can be collected to serve as planting stock. The seeds are recalcitrant. They are very susceptible to desiccation. There is progressive deterioration of the internal tissues of the seeds associated with fungal infection during hydrated storage. Experiments with seedlings resulted in approximately 90% survival. Young seedlings grow best when they are in contact with fresh water, but growth diminishes soon under these conditions and is best in water with 10–50% of full seawater salinity for older seedlings. There appears to be no restriction to establishment of seedlings within mangrove stands, but recruitment to the sapling stage appears to be restricted by light and sediment resources. Propagation by air layering and root suckers has been successful.
Management
In many mangrove regions, the potential of Avicennia marina is considered limited and other mangrove species such as Rhizophora spp. are often more highly valued for timber, firewood, charcoal, dye and tannin production. Although mangroves are often heavily exploited, Avicennia marina is often left. Trees suffer little from removal of branchwood because they can resprout rapidly from buds along the stems.
Diseases and pests
In Australia the leaves, flowers and seedlings are affected by leaf blight caused by Alternaria alternata.
Crabs consume the propagules and may be the main reason for the absence of Avicennia marina in certain areas. The mangrove decapod crab Neosarmatium meinerti, which is very common in the Avicennia marina zone along the East African coast, feeds heavily on seedlings and fallen leaves.
Genetic resources
Avicennia marina is one of the most common species in mangrove vegetations, being a pioneer species with great power of natural regeneration. As such, it does not seem liable to genetic erosion. However, in many regions of tropical Africa mangroves have been under much pressure because of clearing for other land uses and exploitation for fuel.
In populations in tropical Asia and Australia, it was shown that a very high level of genetic structure and inbreeding exists and that populations are functioning as independent evolutionary units more than as components of a metapopulation system connected by gene flow. This makes peripheral populations likely to develop local adaptations and therefore to be of particular interest for conservation strategies as well as for adaptation to possible future environmental changes.
Prospects
Mangroves are socio-economically important ecosystems for the inhabitants of coastal regions, but they are under high pressure worldwide. As one of the main constituents of mangrove vegetations in Africa, Avicennia marina deserves protection. Its role in future timber production in tropical Africa seems very limited because the boles are often too small and of too poor shape to be interesting for commercial timber exploitation. It can be planted for mangrove restoration, because it exhibits wide physiological tolerance and it creates a suitable environment for other mangrove species after it has become well established.
Major references
• Arnaud-Haond, S., Teixeira, S., Massa, S.I., Billot, C., Saenger, P., Coupland, G., Duarte, C.M. & Serrao, E.A., 2006. Genetic structure at range edge: low diversity and high inbreeding in Southeast Asian mangrove (Avicennia marina) populations. Molecular Ecology 15(12): 3515–3525.
• Bein, E., Habte, B., Jaber, A., Birnie, A. & Tengnäs, B., 1996. Useful trees and shrubs in Eritrea: identification, propagation and management for agricultural and pastoral communities. Technical Handbook No 12. Regional Soil Conservation Unit, Nairobi, Kenya. 422 pp.
• Chua, L.S.L., 1998. Avicennia L. In: Sosef, M.S.M., Hong, L.T. & Prawirohatmodjo, S. (Editors). Plant Resources of South-East Asia No 5(3). Timber trees: Lesser-known timbers. Backhuys Publishers, Leiden, Netherlands. pp. 92–94.
• Coates Palgrave, K., 1983. Trees of southern Africa. 2nd Edition. Struik Publishers, Cape Town, South Africa. 959 pp.
• Han, L., Huang, X., Dahse, H.M., Moellmann, U., Fu, H., Grabley, S., Sattler, I. & Lin, W., 2007. Unusual naphthoquinone derivatives from the twigs of Avicennia marina. Journal of Natural Products 70(6): 923–927.
• Maundu, P. & Tengnäs, B. (Editors), 2005. Useful trees and shrubs for Kenya. World Agroforestry Centre - East and Central Africa Regional Programme (ICRAF-ECA), Technical Handbook 35, Nairobi, Kenya. 484 pp.
• Naidoo, G., 2006. Factors contributing to dwarfing in the mangrove Avicennia marina. Annals of Botany 97(6): 1095–1101.
• Palmer, E. & Pitman, N., 1972–1974. Trees of southern Africa, covering all known indigenous species in the Republic of South Africa, South-West Africa, Botswana, Lesotho and Swaziland. 3 volumes. Balkema, Cape Town, South Africa. 2235 pp.
• Tomlinson, P.B., 1986. The botany of mangroves. Cambridge University Press, Cambridge, United Kingdom. 413 pp.
• Verdcourt, B., 1992. Verbenaceae. In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. 155 pp.
Other references
• Al Dosari, M.N., 2001. Chemical analysis and in vitro organic matter disappearance of Avicennia marina and Salvadora persica leaves as camel forage in the Tuhama plain at Kingdom of Saudi Arabia. Arab Universities Journal of Agricultural Sciences 9(1): 11–19.
• Beentje, H.J., 1994. Kenya trees, shrubs and lianas. National Museums of Kenya, Nairobi, Kenya. 722 pp.
• Boiteau, P., Boiteau, M. & Allorge-Boiteau, L., 1999. Dictionnaire des noms malgaches de végétaux. 4 Volumes + Index des noms scientifiques avec leurs équivalents malgaches. Editions Alzieu, Grenoble, France.
• Bousquet Melou, A. & Fauvel, M.T., 1998. Inter-specific variation in the concentration of two iridoid glucosides in Avicennia L. (Avicenniaceae Endl.). Biochemical Systematics and Ecology 26(8): 935–940.
• Chandrashekar, M. & Ball, M.C., 1980. Leaf blight of grey mangrove in Australia caused by Alternaria alternata. Transactions of the British Mycological Society 75(3): 413–418.
• Clarke, P.J., 1992. Predispersal mortality and fecundity in the grey mangrove (Avicennia marina) in southeastern Australia. Australian Journal of Ecology 17(2): 161–168.
• Clarke, P.J., 1993. Dispersal of grey mangrove (Avicennia marina) propagules in southeastern Australia. Aquatic Botany 45(2–3): 195–204.
• Clarke, P.J. & Allaway, W.G., 1993. The regeneration niche of the grey mangrove (Avicennia marina): effects of salinity, light and sediment factors on establishment, growth and survival in the field. Oecologia 93(4): 548–556.
• Clarke, P.J. & Myerscough, P.J., 1991. Floral biology and reproductive phenology of Avicennia marina in south-eastern Australia. Australian Journal of Botany 39(3): 283–293.
• Clough, B.F., 1984. Growth and salt balance of the mangroves Avicennia marina (Forsk.) Vierh. and Rhizophora stylosa Griff. in relation to salinity. Australian Journal of Plant Physiology 11(5): 419–430.
• Dahdouh-Guebas, F., Verneirt, M., Tack, J.F. & Koedam, N., 1997. Food preferences of Neosarmatium meinerti de Man (Decapoda: Sesarminae) and its possible effect on the regeneration of mangroves. Hydrobiologia 347: 83–89.
• Decary, R., 1946. Plantes et animaux utiles de Madagascar. Annales du Musée Colonial de Marseille, 54e année, 6e série, 4e volume, 1er et dernier fascicule. 234 pp.
• Downton, W.J.S., 1982. Growth and osmotic relations of the mangrove Avicennia marina, as influenced by salinity. Australian Journal of Plant Physiology 9(5): 519–528.
• Duke, N.C., 1991. A systematic revision of the mangrove genus Avicennia (Avicenniaceae) in Australasia. Australian Systematic Botany 4: 299–324.
• InsideWood, undated. [Internet] http://insidewood.lib.ncsu.edu/search/. Accessed May 2007.
• Moldenke, H.N., 1956. Avicenniacées (Avicenniaceae). Flore de Madagascar et des Comores (plantes vasculaires), familles 174–174 bis. Firmin-Didot et cie., Paris, France. 5 pp.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• Schatz, G.E., 2001. Generic tree flora of Madagascar. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 477 pp.
• Schwarzbach, A.E. & McDade, L.A., 2002. Phylogenetic relationships of the mangrove family Avicenniaceae based on chloroplast and nuclear ribosomal DNA sequences. Systematic Botany 27(1): 84–98.
• Thulin, M., 2006. Avicenniaceae. In: Thulin, M. (Editor). Flora of Somalia. Volume 3. Angiospermae (cont.). Royal Botanic Gardens, Kew, Richmond, United Kingdom. p. 454–455.
• van Wyk, B.E. & Gericke, N., 2000. People’s plants: a guide to useful plants of southern Africa. Briza Publications, Pretoria, South Africa. 351 pp.
Sources of illustration
• Bein, E., Habte, B., Jaber, A., Birnie, A. & Tengnäs, B., 1996. Useful trees and shrubs in Eritrea: identification, propagation and management for agricultural and pastoral communities. Technical Handbook No 12. Regional Soil Conservation Unit, Nairobi, Kenya. 422 pp.
• Maundu, P. & Tengnäs, B. (Editors), 2005. Useful trees and shrubs for Kenya. World Agroforestry Centre - East and Central Africa Regional Programme (ICRAF-ECA), Technical Handbook 35, Nairobi, Kenya. 484 pp.
• Verdcourt, B., 1992. Verbenaceae. In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. 155 pp.
Author(s)
N.S. Alvarez Cruz
Unidad de Medio Ambiente, Delegación del CITMA, Cor. Legon 268 / Henry Reeve y Carlos Roloff, Sancti Spiritus 60100, Cuba


Editors
D. Louppe
CIRAD, Département Environnements et Sociétés, Cirad es-dir, Campus international de Baillarguet, TA C-DIR / B (Bât. C, Bur. 113), 34398 Montpellier Cedex 5, France
A.A. Oteng-Amoako
Forestry Research Institute of Ghana (FORIG), University P.O. Box 63, KNUST, Kumasi, Ghana
M. Brink
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
General editors
R.H.M.J. Lemmens
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
L.P.A. Oyen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
J.R. Cobbinah
Forestry Research Institute of Ghana (FORIG), University P.O. Box 63, KNUST, Kumasi, Ghana
Photo editor
G.H. Schmelzer
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article:
Alvarez Cruz, N.S., 2008. Avicennia marina (Forssk.) Vierh. In: Louppe, D., Oteng-Amoako, A.A. & Brink, M. (Editors). Prota 7(1): Timbers/Bois d’œuvre 1. [CD-Rom]. PROTA, Wageningen, Netherlands.
Distribution Map wild


1, tree habit; 2, flowering twig; 3, flower; 4, fruit.
Redrawn and adapted by Iskak Syamsudin



tree habit CopyLeft EcoPort


breathing roots (pneumatophores) CopyLeft EcoPort


leafy branch CopyLeft EcoPort


inflorescence CopyLeft EcoPort


transverse surface of wood


wood in transverse section


wood in tangential section


wood in radial section