email@example.com (corresponding author),
species in the southern Eastern Ghats of India. Journal of Threatened Taxa 6(9): 6153–6171; http://dx.doi.org/10.11609/JoTT.o3768.6153-71
and distribution by providing adequate credit to the authors and the source of publication.
tabulated the observational and experimental work of the paper.
endemic and endangered plant species in southern Eastern Ghats forests with financial support from MoEF and CSIR. J. Radha Krishna is working as a Junior
Research Fellow in the MoEF&CC research project registered for a PhD degree under Prof. A.J. Solomon Raju. P. Hareesh Chandra is working as a senior research
fellow in the MoEF&CC research project registered for a PhD degree under Prof. A.J. Solomon Raju.
species (MoEF No. 22/6/2010-RE) funded by the Ministry of Environment, Forests & Climate Change, New Delhi sanctioned to AJSR. The second author is JRF
and third author is SRF working in this project. We thank Mr. K. Venkanna, Technical Officer, Central Research Institute for Dry land Agriculture, Hyderabad, for
doing soil NPK analysis.
India. It is a mass bloomer with flowering during dry season. The floral traits suggest a mixed pollination syndrome involving entomophily
and anemophily together called as ambophily. Further, the floral traits suggest generalist pollination system adapted for a guild of
pollinating insects. The plant is self-incompatible and obligate out-crosser. The flowers are many-ovuled but only a single ovule forms
seed and hence, fruit and seed set rates are the same. Natural fruit set stands at 11%. Bud infestation by a moth, flower predation by
the beetle, Popillia impressipyga and bud and flower mounds significantly limit fruit set rate. The ability of the plant to repopulate itself is
limited by the collection of fruits by locals due to their edible nature, short viability of seeds, high seedling mortality due to water stress,
nutrient deficiency and erratic rainfall or interval of drought within the rainy season. Therefore, S. alternifolium is struggling to populate
itself under various intrinsic and extrinsic factors. Further studies should focus on how to assist the plant to increase its population size in
its natural area taking into account the information provided in this paper.
insects (Crome & Irvine 1986) while S. paniculatum is
pollinated by honeybees, hawk moths, honeyeaters
and butterflies (Payne 1991, 1997). S. floribundum is
pollinated by a guild of short-tongued unspecialized
insects (Williams & Adam 2010). In American Samoa,
foraged by birds (Cox et al. 1992). S. dealatum is both
entomophilous and anemophilous (Webb & Solek 1996).
Empirical studies on the pollination of other Syzygium
species in Samao are absent but observers have
suggested that bats are important pollinators of these
species (Wiles & Fujita 1992; Trail 1994; Banack 1996). In
Sulawesi, S. syzygiodes is pollinated by a variety of short-
tongued unspecialized insects (Williams & Adam 2010).
In East Java, S. pycnanthum attracts a variety of insects
but their pollination role has not been studied (Mudiana
& Ariyanti 2010). In Africa, S. guineense is reported to
be a honeybee plant but details of pollination are lacking
(Verdcourt 2001). In Mauritius, S. mamillatum is a rare
and endemic cauliflorus species and it is pollinated by
a variety of birds (Kaiser et al. 2008). In India, only S.
pollination biology. S. mundagum in the Western Ghats
is pollinated exclusively by bats while seed dispersal
takes place largely by bats (Ganesh 1996). S. cuminii
is pollinated by wind, insects and gravity (Misra &
Bajpai 1984; Bajpai et al. 2012). Despite the richness of
other species has not been studied so far.
forests of Kurnool, Cuddapah and Chittoor districts of
Andhra Pradesh, Chengalpattu and North Arcot districts
of Tamil Nadu and Bangalore District in Karnataka in
India (Gamble 1957; Chitra 1983; Saldanha 1996; Reddy
et al. 2006). Mohan & Lakshmi (2000) reported that S.
valley tops with dry, slaty and rocky conditions at an
elevation ranging from 600–1000 m in Sri Venkateswara
Wildlife Sanctuary of Chittoor and Cuddapah districts.
They stated that the distribution of this species appears
to be related to the geology and rock structure along
with elevation and aspect.
S. alternifolium is a fruit tree of great timber,
medicinal and economic importance. Timber is used
for making furniture and agricultural implements.
The plant tops are used to cure skin diseases as it has
The leaves are used in the treatment of liver cirrhosis,
hepatitis, infective hepatitis, liver enlargement, jaundice
and other ailments of liver and gall bladder. Leaves fried
in cow ghee are used as a curry to treat dry cough. A
Syzygium (Myrtaceae) is native to the tropics,
particularly to tropical America and Australia. It has
a worldwide, although highly uneven, distribution in
tropical and subtropical regions. It is known from many
countries including South Africa, South America, South
East Asia and Australia. The genus comprises about
1,100 species, and has a native range that extends
from Africa and Madagascar through southern Asia
east through the Pacific. Its highest levels of diversity
occur from Malaysia to northeastern Australia, where
many species are very poorly known and many more
have not been described taxonomically (Wrigley & Fagg,
2003). In India, Syzygium has 75 species. This genus
is of commercial importance with timber yielding plants
such as S. aqueum and S. bracteatum and with fruit
trees such as S. cuminii and S. aromaticum which are
highly adapted to adverse conditions. The fruits of many
plants are edible and found to be used in local medicine
(Anonymous 1956). A list of 18 Syzygium species is
included in the International Union for the Conservation
of Nature (IUCN) Red List Plants of India (Reddy & Reddy
2008). They are S. andamanicum, S. courtallense,
Endangered), S. beddomei, S. bourdillonii, S. chavaran,
Deficient) and S. gambleanum (Extinct). Reddy & Reddy
(2008) documented that S. alternifolium is an endemic
and globally endangered species as per the criteria of
IUCN but not yet included in the IUCN Red List.
Sanewski (2010) stated that the studied species of
both self-compatible and self-incompatible species
exist in this genus but the self-compatible species are
most common. The author documented some self-
compatible species which include S. tierneyanum and S.
nervosum from north Australia (Hopper 1980; Shapcott
1998), S. cuminii from India (Reddi & Rangaiah (1999–
2000), S. rubicundum from Sri Lanka (Stacey 2001),
S. lineatum from Indonesia (Lack & Kevan 1984), and
S. samarangense, S. jambos, S. megacarpum, and S.
formosum from Thailand (Chantaranothai & Parnell
1994). In Australia, a variety of nectar feeding animals
visit and pollinate S. tierneyanum while blossom bats and
honeyeaters are primary pollinators of S. sayeri, although
butterflies, flies, thrips and wasps also playing a role in
pollination (Williams & Adam 2010). S. cormiflorum
is mainly pollinated by bats and followed by birds and
mixture of leaves and mineral oil is used to maintain
dark hair and also to promote hair growth by external
application to the scalp. Tender shoots, fruits and leaf
juice are used to treat dysentery, seeds for diabetes
and stem bark for gastric ulcers. Flowers yield honey
and possess antibiotic properties. The ripe fruits are
used in making squashes and jellies. Fruit juice is used
to cure stomach-ache and ulcers while the external
application of fruit pulp reduces rheumatic pains (Reddy
et al. 1989; Nagaraju & Rao 1990; Rao & Rao 2001;
Bakshu 2002; Mohan et al. 2010). Despite its multiple
medicinal and economic uses, the plant has not been
studied for any aspect of pollination ecology. In recent
years, its population size is declining due to cut down
of trees and collection of fruits leaving less possibility
for the plant to repopulate itself in its natural area.
Keeping this in view, the present study is contemplated
to describe the chronological events of pollination
biology of S. alternifolium (Wight) Walp. (Myrtaceae).
The observational and experimental data collected on
the studied aspects are discussed in the light of relevant
existing information on other Syzygium species.
MATERIALS AND METHODS
A population of about 80 individuals of S. alternifolium
located in the hill and slopes of Tirumala (13
20”E, 858m) was used for the study during 2011–
region is declared in 2011 as Seshachalam Biosphere
Reserve by the Ministry of Environment and Forests,
Government of India. The reserve lies between 13
55”N & 79
24”E. It is spread over 4756km
Pradesh. The vegetation is a unique mix of the dry
deciduous and moist deciduous types. The elevation
ranges from 150–1,130 m and the terrain undulating
with deep forest-covered valleys and characterized by
steep slopes, rocky terrain, dry and poor stony soils.
The area receives most of the rainfall from northeast
monsoon and little from southwest monsoon (Guptha
et al. 2012).
Field observations on flowering intensity were
made during 2011–2013. Twenty-five trees (Diameter,
Breast and Height 15±4) were tagged for recording the
phenological events for two consecutive years 2011
and 2012. Fifty tagged mature buds from 10 trees were
followed for recording the time of anthesis and anther
dehiscence; the mode of anther dehiscence was also
noted by using a 10x hand lens. Five flowers each from
ten trees selected at random were used to describe the
flower details. Twenty mature but undehisced anthers
from the flowers of 10 different plants were collected
and placed in a petri dish. Later, each time a single
anther was taken out and placed on a clean microscope
slide (75x25 mm) and dabbed with a needle in a drop
of lactophenol-aniline-blue. The anther tissue was then
observed under the microscope for pollen, if any, and
if pollen grains were not there, the tissue was removed
from the slide. The pollen mass was drawn into a band,
and the total number of pollen grains was counted
under a compound microscope (40x objective, 10x
eye piece). This procedure was followed for counting
the number of pollen grains in each anther collected.
Based on these counts, the mean number of pollen
produced per anther was determined. The pollen grain
characteristics were recorded by consulting the book
of Bhattacharya et al. (2006). Pollen dispersal rate
as single grains or in aggregates was ascertained by
gently touching the dehisced anthers and collecting the
liberated pollen on microscope slides placed close to the
anthers. The hourly pollen concentrations in the plant
canopy were determined by operating rot rod samplers.
Pollen spread downwind of the source, during the
period of anther dehiscence was measured at a distance
of 0, 5, 10, 15, 20 and 25 meters using rotor samplers
(Perkins 1957). Five flowers each from ten trees were
used for testing stigma receptivity, nectar volume, sugar
concentration, sugar types, protein content and amino
acids. These aspects were examined following the
protocols given in Dafni et al. (2005). Nectar was also
analyzed for amino acid types by following the Paper
Chromatography method of Baker & Baker (1973).
The foraging activity of insects was observed during
day and night for 15 days in each year. In the 3-year
period, the same insects were recorded. The census of
foraging visits of each insect species was recorded on
three different occasions in each year and the data thus
collected was compiled to arrive at the average foraging
visits made by each species at each hour and for the day.
They were observed with reference to the type of forage
they collected, contact with essential organs to result in
pollination and inter-plant foraging activity in terms of
Bud and flower infestations were also observed
in each study year and recorded their intensity to the
extent possible. Fifty mature buds, five each from
10 inflorescences on five trees were bagged prior
to anthesis around noon time without manual self-
pollination to know whether the fruit set occurs through
autogamy. Another set of 50 mature un-dehisced buds
was selected in the same way and bagged. On the next
day, the bags were removed, manually self-pollinated
and bagged again to know whether fruit set occurs
through manual self-pollination. Another set of 50
mature buds was selected again, then emasculated and
bagged. The next day, the bags were removed and the
stigmas were brushed with the freshly dehisced anthers
from the flowers of the same tree and re-bagged to
know whether fruit set occurs through geitonogamy.
Another set of 50 mature buds was selected in the same
way, then emasculated and bagged. The next day, the
bags were removed and the stigmas were brushed with
freshly dehisced anthers from the flowers of other trees
and re-bagged to know whether fruit set occurs through
xenogamy. Ten inflorescences on each tree were tagged
for fruit set in open-pollination. The bagged flowers and
tagged inflorescences were followed for eight weeks to
record the results.
Fruits and seed characteristics were also recorded.
Field observations on the fruit maturation duration and
dispersal mode were recorded. In vitro experiments for
seed germination rate were conducted in the local forest
nursery. A total of 195 seeds were sown in experimental
bags and followed for result for two months. A total
of 144 seeds germinated within two weeks. Further,
observations were made on seed germination and
seedling establishment rates in natural habitat.
The soil analysis for NPK was done by the Central
Research Institute for Dry land Agriculture, Hyderabad.
Field observations on soil status in natural habitat were
The plant habit, flowers, fruits, seeds, seedlings,
flower foragers and bud and flower infestations were
photographed with a Nikon D40X Digital SLR camera
Magellan Explorist 210 Model Digital Global
Positioning System was used to record the coordinates -
latitude, longitude and altitude.
tree species of dry deciduous forest (Image 1a). Leaf
shedding is partial during January–March. Flower bud
initiation occurs in late March while flowering occurs
during mid-April to mid-May at population level (Image
1c,d). All the trees flowered massively in 2011; moderate
flowering or flowering in a few branches occurred in
only four trees in 2012 and 2013 and in five others only
in 2012. Five others showed scattered flowering on a
few branches only in 2013. Flowering was totally absent
in 11 trees in 2012 and 2013. The flowering lasts 21
days (Range 16–26) in individual trees (Table 1). The
flowering is almost synchronous within the population.
The number of flowers opening each day is initially
small, but increases rapidly, with a peak mass flowering
for a fortnight and then declining rapidly. Leaf flushing
begins at the end of flowering and continues into rainy
season from June–August (Image 1b). The shedding of
still intact old leaves takes place simultaneously.
The flowers are borne in 8.62±1.26 cm long, terminal
and axillary cymes with divaricating branches. Each
inflorescence consists of 22–53 flowers. They are
pedicellate, creamy-white, 16mm long and 2mm wide,
cup-shaped (4mm), actinomorphic, bisexual and sweet
scented. The calyx and corolla are joined to form a
cap over the bud, which falls off as a calyptra due to
the pressure of the growing stamens. The stamens are
epigynous, white, free, polystemonous (127±3), shaving-
brush type and arranged on the rim of the receptacle
in two whorls; the outer whorl stamens are 9mm long
while inner whorl stamens 6mm long. The filaments are
bent inwards in the bud condition but straighten at the
time of anthesis. The anthers are 1mm long, versatile,
dithecous and introrse. The ovary is bicarpellary and
bilocular syncarpous; it is 4mm long and contains 21–38
ovules on axile placentation (Image 1n). The style tipped
with semi-wet simple stigma is 8mm long when fully
grown, arises from the center of the cup and stretches
out of the stamen ring by 2–3 mm (Image 1lm).