From Plant
Resources of South-East Asia No 2: Edible fruits and nuts, PROSEA
Foundation
by T. G. van Lingen
Taxon
Syzygium jambos (L.) Alston
Protologue
Trimen, Handb. Fl. Ceylon 6, Suppl.: 116 (1931).
Family
MYRTACEAE
Chromosome
Numbers
2n = variously recorded as 28, 33, ?42, 44, 46, ?54, 66.
Synonyms
Eugenia jambos L. (1753).
Vernacular
Names
Roseapple,
Malabar plum (En). Pome rose, jambosier (Fr). Indonesia: jambu air
mawar, jambu mawar, jambu kraton. Malaysia: jambu kelampok, jambu
mawer. Philippines: tampoy (Tagalog), bunlaun (Bisaya), yambo.
Cambodia: châm'-puu. Laos: chièng, kièng. Thailand: chomphu-namdokmai
(central), manomhom (northern), yamu-panawa (Malay-Yala). Vietnam: l,
bô dào, roi.
Origin and
Geographic Distribution
Roseapple
originates in South-East Asia, its centre of origin being Malesia. From
there it has been spread throughout the tropics. It has now become
naturalized in many tropical countries. It is not a crop for commercial
orchards, but the trees are widely grown in home gardens.
Uses
The fresh fruit is somewhat
insipid and often left for the children to pick. The fruit is also
cooked or preserved in various ways for home use. It can be distilled
to yield a rosewater that is said to be equal to the best obtained from
rose petals.
A yellow-coloured essential oil, important in the
perfume industry, is derived from the leaves by distillation. The
heartwood is heavy and hard and is suitable for use as construction
timber. However, the wood is very susceptible to termite attack and not
durable in the soil. The bark contains 7% tannin on a dry weight basis
and is used for tanning and dyeing purposes. The plant is a useful
melliferous and ornamental species; with its regular shape, attractive
foliage and striking appearance in bloom, it is a useful avenue tree
along driveways, etc. Several parts are used medicinally as a tonic or
a diuretic.
Properties
The fruit
contains per 100 g edible portion: water 84—89 g, protein 0.5—0.8 g,
fat 0.2—0.3 g, carbohydrates 9.7—14.2 g, fibre 1—2 g, ash 0.3—0.4 g,
carotene 123—235 IU, vitamin B complex 0.55—1.04 mg and vitamin C 3—37
mg. The energy value is 234 kJ/100 g. The pulp has a high pectin
content, making it suitable for use as a settling agent.
The
essential oil extracted from the leaves contains 27% d l-ALFA-pinene
and 24% l-limonene, two cyclic monoterpenes, responsible for the
pleasant smell of the oil.
Several parts of the plant — i.e. the
seeds, the leaves, the stems, the roots and the bark — are poisonous
due to the presence of the alkaloid jambosine and hydrocyanic acid.
Botany
Evergreen tree, up to
10 m tall and 50 cm trunk diameter, often low branching and with a
dense crown of wide-spreading branches; stem terete, sometimes
quadrangular when young, generally twisted at the base, with brown,
furrowed, smooth bark. Leaves opposite, oblong-lanceolate, 9—26 cm x
1.5—6 cm, thinly coriaceous, cuneate at base, acuminate at apex, glossy
dark-green above, lighter green and obscurely glandular punctate
beneath, petiole 5—6(—13) mm. Inflorescences short terminal or axillary
corymbs, 5—10 cm long, 4—5(—10)-flowered; flowers large, 5—10 cm wide,
white to greenish-white; calyx lobes 4, suborbicular, up to 10 mm x 7
mm; petals 4, suborbicular, 15—18 mm diameter, white to greenish-white;
stamens about 400, up to 4 cm long; style up to 4 cm long; pedicel up
to 1.5 cm long. Fruit a drupe, globose to ovoid, 2.5—5 cm diameter,
crowned by persistent calyx and style, whitish-yellow, sometimes
pink-blushed, fragrant; pericarp fleshy, yellow-pink. Seeds 1—2(—4),
subglobose, 1—1.6 cm diameter, brown, rough coated, polyembryonic.
The
tree grows in more or less synchronous flushes, one of which brings on
bloom. Bloom occurs after a quiescent period, e.g. in spring in the
subtropics, late in the dry season in East Java. The fruit ripens 3
months after bloom. The rosewater smell of the fruit is distinctive for
the species.
Ecology
Roseapple is a tree
of the tropics which has penetrated into the subtropics. It thrives up
to about 1200 m above sea level. At much higher elevations and towards
its limits in the subtropics it bears no fruit. It withstands minimum
temperatures down to 0°C.
Young plants require a shady and moist
environment, but established trees are rather hardy. The tree prefers a
wet climate but also grows in monsoon climates with a taxing dry
season. It is not clear whether flowering and/or fruiting are set back
under dry conditions; recommendations to ensure access to soil moisture
and the observation that trees do not shed their leaves easily suggest
that the tree is not really drought-resistant. On the other hand, the
trees are said to tolerate wind and salt.
There are virtually no
limitations on soil conditions; the tree copes with poor drainage as
well as flooding and grows on various soil types. The recommended pH is
between 5.5—7.0.
Agronomy
Roseapple is
normally propagated by seed. The seeds have no dormancy and germinate
well. A single seed often gives rise to 3—8 seedlings, most of which
are true to type. Other methods of propagation include air layering,
budding and grafting. Air layering is commonly done in India and
Bangladesh during the quiescent season. The layers are planted after
half a year. Roseapple can be budded on 10—12-month-old rootstocks
using the modified Forkert method; Syzygium pycnanthum Merr. & Perry and Syzygium samarangense
(Blume) Merr. & Perry can also serve as rootstocks. The spacing is
about 5 m x 6 m. Initially shade is provided. The juvenile phase lasts
4—5 years; air layered trees bear fruit within 4 years. The tree is
hardly ever given any special attention.
Roseapple does not seem to suffer much from any insect pests, but it is a host to most fruit flies (Anastrepha and Ceratitis spp. as well as Dacus spp.). It is attacked by several fungi, causing leaf spots, anthracnose and root rot.
The
only indication of yield level is from India: 2 kg per tree per year.
This is quite low, even taking into account that the fruit is not
heavy. The fruits, if meant to be consumed fresh, should be handled
with care and marketed as quickly as possible. The fruits bruise easily
and rapidly lose their crispness. The fruit is non-climacteric. Three
days after harvest, respiration and ethylene production decline to
respectively 50% and 10% of their initial values. The colour does not
change during storage.
Genetic Resources and Breeding
Whereas
some authors maintain that the trees are rather variable, others do not
mention this aspect. There are no cultivars. For successful selection
or breeding work, a better insight into yield, yield-limiting factors,
and variability of characteristics is necessary. Such work may also be
directed towards enhancing the production of essential oils or the
ornamental value. However, germplasm collections have yet to be
established.
Prospects
There have always been advocates who claim that roseapple is one of the best if not the best Syzygium
fruit. However, the marketplace has never vindicated these claims. Low
yield, susceptibility to bruising and short shelf life are serious
handicaps. Therefore, it is to be expected that roseapple will remain a
home garden tree, appreciated for its ornamental value as much as for
its fruit.
Perhaps there is scope for the roseapple as an
agroforestry species in denuded areas where soil conservation is
important. In addition to producing timber, the stand might be used for
the essential oil in the leaves, the pectin in the fruit, or as forage
for bees.
Literature
Akamine, E.K. & Goo, T., 1979. Respiration and ethylene production in fruits of species and cultivars of Psidium and species of Eugenia. Journal of the American Society for Horticultural Science 104 (5): 632—635.
FAO-SIDA, 1982. Fruit-bearing forest trees. FAO Forestry Paper 34. Rome. pp. 71—73.
Fish, B.E., 1976. The roseapple. Californian Rare Fruit Growers Yearbook 8: 100—111.
Morton, J.F., 1987. Fruits of warm climates. Creative Resource Systems Inc., Winterville, USA. pp. 383—386.
Whistler, W.A., 1988. A revision of Syzygium (Myrtaceae) in Samoa. Journal of the Arnold Arboretum 69: 167—192.
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