Pachira aquatica (PROSEA)

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Plant Resources of South-East Asia
Introduction
List of species


Pachira aquatica Aubl.


Family: Bombacaceae

Synonyms

Bombax aquaticum (Aubl.) K. Schumann, Carolinea princeps L.f., Pachira macrocarpa (Schltdl. & Cham.) Walp.

Vernacular names

  • Guiana chestnut, saba nut, Malabar chestnut (En). Châtaigner de la Guyane, noisetier de Cayenne (Fr). Castanheiro da Guyana, zapote bobo (Port). Castaño de agua, castaño de la Guayana (Sp).

Distribution

Native to tropical America, from southern Mexico through Central America to Ecuador, northern Peru and northern Brazil. It is also cultivated pantropically.

Uses

The oil obtained from the seed is used to make margarine and is suitable for industrial purposes. It smells like liquorice and fenugreek. Seeds are eaten raw, roasted or cooked and taste like chestnut or groundnut. Only fresh seed should be eaten raw otherwise they have a bitter flavour. In Panama and Colombia a kind of bread is made from ground seeds. Seeds of large fruit types are a substitute for cocoa. The young leaves and flowers are eaten cooked as a vegetable. A yellow dye from the bark colours sails, fishing nets and ropes. In its native area the wood of the tree is utilized as timber. In traditional medicine the seed is used as a cure for eye diseases; the bark and immature fruits to treat liver afflictions in Guatemala; the bark against diabetes in Panama. P. aquatica is a popular ornamental for its showy flowers, planted in gardens, as a wayside tree and even as an indoor plant wherever it will grow.

Observations

Evergreen, unarmed tree, in cultivation often a large shrub, up to 25 m tall, trunk up to 90 cm in diameter, often with narrow buttresses reaching 2 m, bark smooth, grey-brown, inner bark reddish with white spots; in swamps it may develop stilt roots. Leaves arranged spirally, palmately compound, glabrous, 5-9-foliolate; stipules ovate, about 1 cm long; petiole up to 24 cm long, often ribbed, swollen at both ends; petiolule up to 2.5 cm long, leaflet blade elliptical to oblong, 5-30 cm × 3-15 cm, base acute and decurrent to petiolule, apex caudate-acuminate to apiculate, veins prominent especially at lower surface. Flowers usually solitary, 17-35 cm long, appearing before the upper leaves, bisexual, sweetly aromatic; pedicel stout, up to 6 cm long; calyx campanulate, 1-2 cm long, truncate or with 5 obscure lobes; petals 5, valvate, linear, 17-34 cm × 1-2 cm, greenish outside, cream inside, puberulous; stamens 200-260, erect to spreading, 16-31 cm long, variously united in small clusters basally to middle, the clusters finally uniting with staminal column, white basally, reddish in apical third, anthers horse-shoe shaped, 1-celled, 3-5 mm long, reddish, dehiscing by straightening; ovary broadly ovoid, about 1 cm long, 5-celled, style club-shaped, coloured like stamens but longer, stigma with 5 small lobes. Fruit a reddish-brown, woody capsule, ellipsoid to subglobose, up to 30 cm × 12 cm, shallowly 5-sulcate, valves 5, densely red-brown hairy outside, appressed-silky pubescent inside, usually with 2-3 seeds per carpel, in total weighing up to 3 kg. Seed irregularly angulate, 3-6 cm long at maturity, brown, buoyant, embedded in solid, white, fleshy mesocarp. P. aquatica occurs in tropical, usually rather open freshwater swamps, sometimes in or at the edge of brackish water at sea-level, along stream banks up to 300 m altitude. It is a non-halophytic species of coastal mangrove vegetation, preferring an average annual rainfall of 2000-5000 mm, an average annual temperature of 22-28°C and a pH of 6-8.5. P. aquatica can start flowering and fruiting when it reaches 2 m in height. In Central America it flowers throughout the year but most abundantly in February-April, most of the fruits mature in March-August, and new leaves appear around May. P. aquatica can be propagated by seed and by cuttings. Seed may germinate while floating in water and establish a root system upon reaching soil. P. aquatica is sometimes infested by a Cercospora -like fungus, causing necrotic leaf spots. The seed yields about 40% oil which is semi-solid at room temperature. Palmitic acid (55-75%) is the main fatty acid of the oil which also contains α-hydroxysterculic acid (13%). The bark of P. aquatica contains the fungitoxin isohemigossypolone which in pure form showed a clear antifungal activity against Pythium ultimum at a minimum concentration of 10µg per Petri dish. Because of the high oil content of the edible seed and its ornamental value, P. aquatica is worth considering for introduction into South-East Asia, especially for slightly brackish or freshwater swamp locations.

Selected sources

16, 17, 19, 32, 33, 39, 68, 84, 102, 103, 110, 111, 117, 118, 119, 135.