Persea thunbergii (PROSEA)
Introduction |
Persea thunbergii (Siebold & Zucc.) Kosterm.
- Family: Lauraceae
Synonyms
Machilus arisanensis (Hayata) Hayata, M. thunbergii Sieb. & Zucc., Persea arisanensis (Hayata) Kosterm.
Vernacular names
- Chinese bandoline wood, tabu (En).
Distribution
Japan, Korea, Taiwan, China and northern part of Indo-China. It is occasionally cultivated, also elsewhere.
Uses
The seed contains 65% oil but details about the use of the oil are not known. The wood is sometimes used as timber (collective trade name of Lauraceae timber is "medang"). Shavings of the wood yield a mucilage when soaked in water, which is used by Chinese women for pomading their hair. The wood also constitutes a mosquitorepellent incense, with also termiticidal activity. The leaves yield an essential oil. In Chinese traditional medicine the bark is applied against eczema, as a remedy for diseases of the spleen and stomach, and to treat asthma. The powdered bark is used to correct bad odour and in Korea to treat headache, apoplexy and dyspepsia.
Observations
Evergreen, glabrous tree or shrub, up to 15 m tall or taller; branchlets with large terminal buds. Leaves arranged spirally, simple, coriaceous; petiole 1-3 cm long; blade oblanceolate, obovate, oblong or elliptical, 6-15 cm × 3-7 cm, base cuneate, acute or obtuse, margin entire or slightly revolute, apex obtuse to abruptly cuspidate, upper surface lustrous, lateral veins 7-12 pairs, veinlets distinctly reticulate beneath. Inflorescence a terminal-axillary cymose panicle, up to 10 cm long, peduncle 3-5 cm, pedicel 6-9 mm long; flowers bisexual with 6 elliptical-oblong tepals, about 5-7 mm × 2.5 mm; fertile stamens 9, in 3 whorls, subequal, filaments 2.5 mm long, first and second whorl eglandular, anthers 4-locular, introrse, third whorl with 2 glands, anthers extrorse, fourth whorl consists of 3 staminodes 1.5 mm long; ovary globose, 1.3 mm in diameter, style slender, 2.5 mm long, stigma capitate, 3-lobed. Fruit a compressed-globose, black-purple berry, 1 cm in diameter, with persistent reflexed enlarged tepals at base and containing 1 seed. P. thunbergii occurs in primary and secondary forest, from sea-level up to 2100 m altitude. In Korea it is found in areas with average temperatures of about 12°C and an average annual precipitation of 1000 mm. In Japan, seedlings could establish on young lava and scoria. In Taiwan , P. thunbergii flowers in February-May and fruits in June-August. The tree produces a large number of seeds in alternate years. It has higher sapling densities and shows a larger height-growth rate in forest gaps than under closed canopy. P. thunbergii is propagated by seed, by cuttings or through in vitro bud culture. The seed is dispersed by birds, is recalcitrant and sensitive to desiccation. The composition of the seed oil is not known. The essential oil contains 6 major components that differ greatly in quality and quantity between sources: trans-β-ocimene (7-72%), cis-β-ocimene (6-24%), α-pinene (3-16%), α-zingiberene (7-9%), α-terpineol (15%) and α-phellandrene (6%). The leaves contain licarins A (2.5 ppm) and licarins B (26 ppm). Termiticidal activity occurring in the wood is not affected by tree age and may cause 50% mortality to termites ( Coptotermes formosanus ). In Taiwan, P. thunbergii was severely defoliated by the casuarina moth ( Lymantria xylina ); in Japan, it is the host of the redspotted longicorn beetle ( Eupromus ruber) which may cause severe damage to the tree. The potential value for South-East Asia deserves investigation.
Selected sources
12, 24, 35, 54, 60, 61, 62, 65, 71, 73, 75, 90, 92, 94, 95, 97, 106, 121, 134.