BANGLADESH JOURNAL OF FOREST SCIENCE
A Half-yearly Peer Reviewed Journal of Bangladesh Forest Research Institute
A Half-yearly Peer Reviewed Journal of Bangladesh Forest Research Institute
The term allelopathy, literally meaning
mutual harm, refers to the positive or negative
influences of one plant with or without microbial
action upon anotherthroughchemicalmeans other
than nutritional. Allelopathy depends on
chemical compounds mainly added to the environment from living plants or dead and decaying
parts(Tang 1986). Thenumber and diversityofthe
compounds involved in allelopathy are growing
rapidly. These chemicals may be produced by
various parts of the plant such as roots and leaves
(Horseley 1977), pollen (Ortega et al. 1988), seeds
or fruits (Friedman et al. 1982), although roots and
leaves are the main sources (Horseley 1977).
Autotoxicity is apparently a negative feature of
allelochemical production avoided by some
species through excreting or sequestering of
chemicals involved in structures. The
allelochemicals can be classified based on the
nature of producers, systematics of donor and
receiver, inhibitory and stimulatory activity or
upon the self or alien origin. During the last few
years effortshave beenmade to exploitallelopathy
for weed management, pest management,
comparison and rational cropping, agroforestry
and other
The exact flowering cycles (from seed to
seed) ofbamboos are known for few species. Most
of the pastreports on bamboo flowering cycles are
based on speculation and estimation (Hasan 1973,
Banik 1991). The flowering cycles for many
species of bamboo from India, Bangladesh and
Myanmar were reported (Cavendish 1905,
Blatter 1930, Bor 1941, Hasan 1973, Bahadur 1980,
Naithani 1990, Banik 1991, Alam 1995). This paper
presentsthe estima ted flowering cycles ofBambusa
burmanica Gamble, B. cacharensis Majumdar and
B. jaintiana Majumdar based on past records and
recent flowering (Table 1)
A study was conducted with 15 lesser used/unused medium density
(0.52-0.68) wood species of Bangladesh to determine their hardboard making
characteristics. The species tested were barta (Artocarpus lakoocha), chalta (Dillenia
iiidica), dakroom (Mitragyna rotundifalia), gab (Diospyros peregrine), hargaza (Dillenia
pcntagynn), jhumka bhadi (Engelhardtia spicata), kamdev (Calophyllum polyanthum),
kao (Garcinia cowa), kasturi (Cinnamomum cecidodaphne), kerung (Pongamia pinnata),
moos (Pterospernium acerifolium), pairag (Canarium risiiiiferum), rata (Aphanamixis
polystachya), tali (Palagttiuni polyanthum) and uriam (Mangifera sylvatica). It wasfound
that all the species except barta, kasturi and uriam produced good or even better
quality hardboard than that ofsundri (Heritierafames) a widely used wood species in
Khulna Hardboard Mills
Teli garjan (Dipterocarpus turbinatus) is the most important indigenous
species included for long term plantation programme in Bangladesh. Site indices
models have been derived for the species in the plantations of Bangladesh. The
selected models derived in the study could be satisfactorily used for teli garjan
plantations having ages 3-60 years and site indices of 25-55 metres based on a base
age or rotation of 45 years.
Eucalyptus camaldulensis poles were treated with 50 : 50 creosote-light
diesel oil mixture. The poles contained an average of 53.85% sapwood which
was readily perishable by wood destroying organisms if untreated. The poles
were treated by the Bethel Full-Cell process using varying pressure and
duration to evaluate the effect on penetration and retention of the preservative
mixture. It was found that with the simultaneous increase of both treating
pressure and time, no significant increase in pentration was achieved. On the
other hand, with the increase of treating pressure only, the retention of
pressrvative in the sapwood was increased significantly. A penetration of 3.5
cm with retention of 318. 45 kg/m3 in the treated sapwood could be obtained
by using 10.57 kg/cm2 pressure for 3 hours. This amount of penetration is
considered adequate to protect the sapwood region of the pole.
One hundred and eight species of macrohymenopterans belonging to
fifteen families and fifty six genera were recorded from the Silent Valley
National Park. The families Sphecidae, Formicidae, Pompilidae and Apidae
contained maximum number of species. The insects were collected from five
habitats, viz., tropical evergreen forest, subtropical broad leaved hill forest,
montane wet temperate forest, low altitude grasslands and high altitude
grasslands. Of the various species recorded in this study, seven genera and
eleven species are new reportsfor Kerala and seven species are new reportsfor
India
The effect ofsalinity on the germination of Sonneratia apetala Buch.-Ham.
was studied. The best germination success was observed in the 0-5 ppt salinity
range with the highest value (98.67%) at the 0 ppt (fresh water) level.
Germination success decreased significantly with the increasing level of
salinity. Increasing salinity also remarkably delayed the germination.
Satisfactory germination success was observed when salt treated seeds were
sown in fresh water condition. This indicates that salt has only a reversible
inhibitory effect on germination. The rate of recovery from the inhibitory effect
ofsalt was not found to be sensitive to the level of salinity, and did not exhibit
any definite relationship with the length of exposure of seed to the saline
condition
Pot culture experiments were carried out in non-pasteurised soil to determine
the effects ofsix different VAM fungi such as Gigaspora margarita, Glomus deserticola,
G. fasciculatiim, G. mosseae, G. monosporum and G. versiforme individually as well as in
combinations with Frankia sp. on the seedling growth of Casuarina equisetifolia.
Inoculation of VAM fungi or Frankia sp. increased the growth and biomass. Among
the different VAM fungi, Glomusfasciculatiim followed by G. versiforme significantly
enhanced the growth, stem girth and biomass. Inoculation with G. monosporum
increased mycorrhizal infection and spore number in the soil. Co-inoculation with
Gigaspora margarita and Frankia sp. significantly increased root colonization and
spore number. Nodule number and nodular biomass were increased with the
inoculation of VAM fungi. They were further increased by inoculations with Frankia
sp. with a maximum in G. mosseae and Frankia sp. inoculated seedlings. Inoculation
with Gigaspora margarita individually orin combination with Frankia sp.significantly
increased tissue P and K concentration. Significant increase of N concentration was
observed in Glomus monosporum inoculation
The paper presents the leaf epidermal micromorphology of 26 bamboo
species under seven genera occurring in Bangladesh both in wild and under
cultivation. The results are presented in a tabular form. The findings indicate
that micromorphological features of abaxial leaf epidermis work as taxonomic
characters at species level. The paper also provides a dichotomous key to
identify bamboo species occurring in Bangladesh based on leaf epidermal
characters
The growth periodicity of clum and rhizome in Melocanna baccifera
clumps were studied. The culm emergence is maximum in July to midSeptember. It was observed that everyday only the middle internode of a
developing culm elongated maximum and moved gradually in successive
order from the base to the tip of the culm. The lower internodes rarely
elongated. The movement and elongation ofrhizome neck in the clump seemed
to take place either slowly or actively throughout the year irrespective of
seasonal variation. The culm emergence and rhizome neck development took
place simultaneously. The growth periodicity of underground rhizome system
and culm on the ground was found to be interrelated and seemed to be
alternating with each other. Periodicity for culm emergence and rhizome neck
development in M. baccifera was influenced by both soil and air temperature
and ambient moisture condition
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