Euterpe precatoria
| Açaí-do-amazonas (Euterpe precatoria) | |
|---|---|
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| Common names | Açaí-do-amazonas, açaí-da-terra-firme, açaí-solteiro, huasaí, mountain cabbage, manaca, palmiche, assaí |
| Scientific name | Euterpe precatoria |
| Family | Arecaceae |
| Genus | Euterpe |
| Order | Arecales |
| Native range | Trinidad, southern Central America and northern South America (Peru, Brazil, Bolivia, Colombia, Ecuador, French Guiana, Guyana, Suriname, Venezuela) |
| Tree size | Solitary, occasionally clustered stems 3–20 m tall, 4–23 cm diameter |
| Fruit | Globose dark-purple to black drupes about 0.9–1.5 cm across on branched infructescences |
| Harvest season | Mainly January–July in Amazonas, March–September in Acre; flooded-forest sites fruit first |
| Uses | Fruit pulp for açaí wine, juices and frozen desserts; palm heart (harvest kills the single stem) |
Euterpe precatoria, the açaí-do-amazonas or açaí palm (also written assaí, and called huasaí in Peru or mountain cabbage in Belize), is a solitary-stemmed palm of the family Arecaceae native to the lowlands of the Amazon basin and adjacent northern South America. [1] The name was first published in 1842 and remains the accepted scientific name; former names such as Euterpe confertiflora, E. jatapuensis, E. petiolata, E. stenophylla and E. subruminata are treated as synonyms. [1][2] It is one of the most abundant plants of Amazonia, estimated at about five billion adult individuals and just over one percent of all adult trees, and it supplies the fruit pulp from which the regional drink açaí wine is made. [3] The açaí name is also used for the closely related clumping palm Euterpe oleracea; the two species are distinct in stem habit and fruit characteristics. [3]
Description[edit | edit source]
Stems are solitary and occasionally clustered, reaching 3–20 m tall and 4–23 cm in diameter; one floristic descriptor gives 15–30 cm diameter for trunks to 20 m. [4] Leaves grow to about 4 m on a yellowish-green crownshaft, and the inflorescence carries up to about 200 rachillae. The fruit is a globose drupe that turns dark-purple to black when ripe, about 1.5 cm across in one descriptor and 0.9–1.3 cm in another. [4]
Two botanical varieties are recognised. Var. precatoria is the tall, usually solitary form of Trinidad and most of the South American range; var. longevaginata (also written longivaginata) is shorter, solitary or clustered, in Colombia and Central America. Molecular work on a small sample is consistent with the two varieties being separate species, and the varietal taxonomy is treated as unsettled. [4][5]
Cultivation[edit | edit source]
Soil and water[edit | edit source]
The species grows across the Amazonian borders of Peru, Brazil, Colombia and Bolivia, in a climate broadly described by 1,900–4,000 mm of rain a year and a mean annual temperature near 26 °C. [6] It spans two contrasting native ground types: well-drained, nutrient-poor terra-firme forest and seasonally flooded baixio (lowland) forest. [7] In the Acre extractive reserves the baixios stand in floodwater about November–March, four to five months each year, and carry about 60 adult palms per hectare against 23 per hectare on terra firme; the flooded-forest populations show the younger, denser structure that makes them the better-managed fruit source. [7][5]
The nursery substrate used in the main seedling experiment was an acid Red Argisol at pH 4.9, and young plants are grown with daily intermittent irrigation to about 80% of field capacity. [8] Acid, moisture-retentive soil with good drainage is the practical starting point for the non-flooded planting: terra-firme palms grow in nutrient-poor, well-drained ground, while baixio palms stand in the seasonal floodwater. [8][5]
Sun and humidity[edit | edit source]
Seedlings are shade-loving. In the Acre nursery trial the best-quality plants came from 75% shade; 20% and 30% shade were inadequate even with fertilizer, and excessive light reduced growth. [8] Field work on the Central American variety similarly describes a palm of the subcanopy that grows best at roughly 50% of full sun. [9] Native sites are humid: the Acre nursery climate averages about 84% relative humidity, and the Costa Rican study forest receives more than 4,000 mm of rain a year. [8][9]
Seasonal changes[edit | edit source]
In Amazonas the main inflorescence emission runs about August–December and the harvest mainly January–July; in Acre fruiting occurs roughly March–September, and flooded baixio sites fruit ahead of terra firme. [5][7] Nurseries grow seedlings under constant light shade with daily irrigation through the growing season, [8] and for a non-flooded planting the dry months of a strong seasonal climate are the period when irrigation matters most. [6][7]
Propagation[edit | edit source]
Seed is the main propagation route: the species cannot be propagated by tillering, and the only documented vegetative propagules are ramets that appear on small, young palms of var. longevaginata in the wild; they decline with mother-palm height, do not develop into adult palms, and are recorded as a natural phenomenon rather than a nursery method. [8][9]
Fresh, cleaned seed germinates best at about 20 °C in either light or darkness, with 35 °C giving the lowest germination in the same trial; alternating 20–30 °C and 25–35 °C regimes were intermediate. [10] Seeds are moisture-sensitive but tolerant of drying: germination is highest at harvest moisture, about 95% at 27% moisture, and declines as the seed dries, still reaching about 69% at 11% moisture; the study classifies the seeds as intermediate in storage behavior, tolerant of drying to at least 11% moisture. [10] Germination is cryptocotyledonar, hypogeal and adjacent-ligular; the process is slow and heterogeneous, with the first seedlings appearing around 20 days after sowing and complete root and ligule emission by about day 60. [11]
Nursery production is straightforward once shade and nutrition are set: best seedling quality in the Acre experiment came from 75% shade with roughly 8 kg of slow-release fertilizer (Osmocote 15-09-12 8-month) per cubic metre of substrate, and the published nursery guidance calls for transplanting seedlings at 40–60 cm of height with at least five active leaves and a thicker collar, four to eight months after emergence. [8] Ramets do not offer a practical shortcut for the home grower. [9]
Because the single-stem form cannot be vegetatively propagated by conventional techniques, attention is turning to somatic embryogenesis from embryogenic callus in suspension culture, a research avenue rather than a home method. [12]
Flowering, fruiting, and harvest[edit | edit source]
Inflorescences are monoecious and protandrous, with one to four emitted per flowering period, and the species is predominantly outcrossing, with a multilocus outcrossing rate near 1.0. [5] Flower visitors recorded across studies are mainly beetles of the families Staphylinidae, Chrysomelidae and Curculionidae together with halictid bees. [5]
In natural stands, trees flower and fruit on a regional calendar: inflorescence emission mainly August–December in Amazonas with harvest January–July, and fruiting roughly March–September in Acre, where flooded baixio forest fruits before terra firme. [5] Productivity in managed extractive stands is reported as ranges by environment rather than a species constant: roughly 2–3 bunches per palm per year with bunch weights of about 8 kg in high várzea, and about 2.25 bunches per palm per year with bunch weights of about 5.5 kg in baixio, representing roughly 2–3 tonnes of fruit per hectare per year in flooded forests. [5] Adult densities in the Acre reserve reached about 60 palms per hectare in baixio against 23 on terra firme. [7]
Fruit and uses[edit | edit source]
The fruit pulp is the edible part: the fresh mesocarp yields the drink called açaí wine, and the same pulp goes into juices, ice cream, smoothies, popsicles and liqueurs. [10][8] The pulp supplies energy, lipids, dietary fibre, minerals such as calcium, magnesium, potassium and phosphorus, vitamins of the B group together with C and E, carotenoids, anthocyanins and phenolic compounds. [10][12] In comparative laboratory studies the pulp has shown higher anthocyanin content and greater antioxidant and anti-inflammatory activity than that of Euterpe oleracea; these are assay-level comparisons, not established health effects. [5][6]
Fruit-pulp products of both açaí species are regulated in Brazil under Normative Instruction No. 37 of 1 October 2018 of the Ministry of Agriculture, and regional açaí of E. precatoria has received geographical indications, with Codajás in Amazonas recognised in 2024 and Feijó in Acre the first açaí GI in Brazil. [5] No formal cultivars or commercial seed lines have been released for this species; production is largely extractive, with genetic-improvement and cultivation-system research ongoing at Embrapa. [5][6]
The apical meristem is eaten as palm heart, but cutting it kills the solitary stem, and heart-of-palm extraction severely reduced populations in Peru and Bolivia during the 1990s; fruit harvest is the sustainable product, and planting for fruit is being encouraged in Brazil. [9][3][8] Traditional uses also include the roots in local medicine and the stems for construction. [3]
Photos[edit | edit source]
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References[edit | edit source]
- ↑ [5] Systematic Review of the State of Knowledge About Açaí-Do-Amazonas (Euterpe precatoria) — PubMed Central.
- ↑ [6] Ramos, S.L.F.; Dequigiovanni, G.; Lopes, M.T.G.; et al. (2021). Genetic Structure in Populations of Euterpe precatoria in the Brazilian Amazon. Frontiers in Ecology and Evolution 8:603448.
- ↑ [7] Rocha, E. (2004). Ecological potential for fruits management of açaizeiro (Euterpe precatoria) in extractive areas in Acre, Brazil. Acta Amazonica 34(2).
- ↑ [8] Environment and slow-release fertilizer in the production of Euterpe precatoria seedlings. Pesquisa Agropecuária Tropical 48(4): 382-389 (Embrapa Acre, 2018).
- ↑ [9] Avalos, G.; Schneider, R.A. (2011). Quantification of ramet production in the neotropical palm Euterpe precatoria (Arecaceae) in Costa Rica. Ecotropica 17: 31-38.
- ↑ [10] Costa, C.R.X.; Pivetta, K.F.L.; de Souza, G.R.B.; et al. (2018). Effects of Temperature, Light and Seed Moisture Content on Germination of Euterpe precatoria Palm. American Journal of Plant Sciences 9: 98-106.
- ↑ [11] Ferreira, C.D.; Silva-Cardoso, I.M.A.; Ferreira, J.C.B.; et al. (2020). Morphostructural and histochemical dynamics of Euterpe precatoria (Arecaceae) germination. Journal of Plant Research 133(5): 693-713.
- ↑ [12] Vasconcelos, A.D.M.; Ferreira, J.C.B.; Meira, R.O.; et al. (2024). Establishment, Multiplication, and Biochemical Analysis of Embryogenic Lines of the Amazonian Palm Euterpe precatoria under Suspension Culture. Forests 15(10): 1804.
Image credits[edit | edit source]
- File:Euterpe precatoria (19866677541).jpg — Euterpe precatoria palm in the Colombian Amazon (açaí/assai palm in habitat; photo 6 January 2012). Creator: Dick Culbert, CC BY 2.0 (license). File page: Wikimedia Commons. Attribution: Dick Culbert, CC BY 2.0, via Wikimedia Commons.
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- File:14020-Euterpe precatoria-Washadi.jpg — Inflorescence and unripe fruit of Euterpe precatoria, Rio Caura near Boca de Nicharé, Venezuela (photo 25 February 2007). Creator: Vojtěch Zavadil, CC BY-SA 4.0 (license). File page: Wikimedia Commons. Attribution: Vojtěch Zavadil, CC BY-SA 4.0, via Wikimedia Commons.
- File:Euterpe precatoria (19866679701).jpg — Edible fruit of the açaí palm (Euterpe precatoria), Colombian Amazon (photo 6 January 2012). Creator: Dick Culbert, CC BY 2.0 (license). File page: Wikimedia Commons. Attribution: Dick Culbert, CC BY 2.0, via Wikimedia Commons.
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- File:13344-palm heart-Rio Caura.jpg — Prepared dish from the palm heart of Euterpe precatoria, Boca de Nicharé, Rio Caura, Venezuela (photo 16 February 2007). Creator: Vojtěch Zavadil, CC BY-SA 4.0 (license). File page: Wikimedia Commons. Attribution: Vojtěch Zavadil, CC BY-SA 4.0, via Wikimedia Commons.
