This paper deals with the iron status of different species of banana
leaves ; the effect of application of sulphur in sail on iron mobilization
and the effect of injection of iron salt solution on iron absorption by
banana leaves.
IRON STATUS OF BANANA LEAVES AND
RESPONSE OF SULPHUR APPLICATION
ON IRON UPTAKE1

Soil and leaf samples were collected from the groves of five edible
banana species grown in a green house, SoiI around the selected
banana plants was treated with sulphur both in the plots and in pots
aop’ying 100, 200 and 300 kg of sulphur per hectare. Two ml of
FeSO4 solution (5000 ppm) was injected on tha pseudosten at tha
base of tha third ycungest leaf. After four weeks, scil and leaf
samples were collected for analysis. Sunflower seedlings grown under
similar sulphur treated conditions were collected efter 20 days.
It was revealed from the results of the analytical data that iron
content in banana leaves vary from one species to the other. But
most of the species selected for this work contained higher amount
of iron in leaves compared to the iron content of sunflower seedlings.
The injection of FeSO4 solution in the pseudostems of iron deficient
banana plants gave expedited response in iron absorption by leaves
compared to the application of sulphur in soil which was done for
increasing the mobilization of iron.

Shrinkage and density were studied for Teak (Tectona grandls) of
five age groups ranging from 20 to 60 years at three height positions.
Linear shrinkages were evaluated from green condition to 15 and O
percent moisture contents. Density was determined on the basis of
green and ovendry volumes. Shrinkage and density were found to be
Independent of the height of the stem. The overall shrinkage and
density were affected by the age factor. The variations in the average
values of different age groups were, however, not observed to be
significantly different in all cases.

CIvit ( Swlntonia florlbunda ) veneer,
dry (1J—12 percent moisture content)
boric acid and 1.9 percent
for 10, 25 and 40 minutes,
three-ply plywood.
1.5 mm thick, both green and
were soaked in 1 25 percent
borax solutions separately at 90° —100°C
These were conditioned and glued into
with a ureaformaldehyde adhesive fortified with
melamine, for producing boil-resistant glue-bond. Plywood shear test
samples were prepared and tested in both dry and wet (boiled in water
for six hoyrs and tested while wet) states.
Dry shear tests show that green veneers treated with both boric
acid and borax, and dry veneers treated with borax had the higher
bond strength, while the longest treating time (40 minutes) had the
lowest bond strength, all the differences being significant at the 5%
level. The wet test shows significant differences at the 5% level
between the preservatives, borax treatment producing better bond
strength However, all the treatment combinations resulted in adequate
bond strength for the type of plywood produced.

Th© lack of knowledge of treatability of timber species with
pressure method may result in poor treatment in reipect of penetration
and retention of the preservative chemical Inwood. This knowledge
for our indigenous timber species was not ascertained before. The
relative penetrability of nineteen timber species was, therefore,
determined with Lowry empty cell process using 40 r 60 creosote
and light diesel oil mixture.
Specific gravity of species did not seem to have any bearing
on the penetration cf preservative. Grain structure and presence of
tyloses appeared to be correlated with penetrability of the wood.
The species were classified into four treatability groups according
to the degree of heartwood penetrability.

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Paper pulps have been prepared from Gamar (Gmelina arborea, Roxb.)
wood of four age groups by the kraft process. Cooks were made with
active alkali and sulfidity ranging from 14,94 percent to 21.05 percent
and 14,12 percent to 20,12 percent respectively at 170° C, The best
pulp was obtained with 16 years old gamar wood at 14,94 percent
active alkali and 14,57 percent sulfidity under optimum condition.
Pulp-yield varied from 40,86 percent to 49,35 perecnt at various ages.
The physical strength and other properties of Gamar kraft pulp compared
favourably with those of other hardwood pulps prepared in the Forest
Research Institute, Chittagong,

Teak fruits were experimentally graded by weight and
graded according to size This gave a total 35 weight-cum-size
grades of fruits The germinative and the average seedling production
capacity of the fruits of each grade were tested. It was found that
the results were influenced by the way the data were arranged and
produced. The weight-cum-size arrangement showed confused, unexpected
and unnatural trends which were difficult to explain but the
size-cum-weight arrangement showed a linear relationship between size
of the fruit and the number of seeds which was according to expectation
and in conformity with the results reported earlier It has, therefore,
been concluded that size of the fruit is primary and the weight is
only secondary in determining the quality of Teak fruits. Grading of
Teak fruits by combining size and weight can give fruit lots upto
50-75 percent germinability and average number of 1.00-2 50 seedlings
per fruit.

Excepting bamboo and sungrass, various grass species growing
in the forest lands of Chittagong, Chittagong Hill Tracts and Sylhet
districts of Bangladesh, at present, have practically no use. Five
grass species, namely, Panicum, antidetale, Retz., Themeda arundinacea,
Ridley., Saccharum spontaneum Linn., Thysanolaena maxima, O, Ktze, and
Imperata arundinacea, Cyr., which are available in the area in appreciable
quantities, have been pulped by steaming and soda processes for the
manufacture of insulation boards in equivalent mixtures as well as in
the proportion of their availability in the forests. The pulps obtained
by the steaming process were free-draining but rather dark in colour.
Soda pulps were lighter in colour but comparatively slow-draining.
Yield was high in both the processes.
Rigid structural insulation boards were made both by press-drying
in a hot hydraulic press at low pressure and by cold pressing the
mats and then drying in a force-draft oven. The boards had very
good strength but moderate heat insulating properties, They compared
favourably with the imported ones so far as the moisture resistance
properties were concerned.

It has been found that the nature
pineapple can be improved by treating
The most obvious effect
both in terms of time and quantity.
for canneries. Moreover, fruits can be
obtained all the year round by artificial
flower induction and advantage taken of
the higher prices for ”offseason” fruits
Tremendous works have been done in
this line in different countries specially
in Australia, Hawaii and Puerto Rico and
some in Bangladesh and a few important
of them have been reviewed in this paper
Under natural conditions, a percentage
of pineapple plants do not flower at the
normal time and, in addition, flowering
may spread over several weeks. But with
the application of hormone the plants can
be forced to flower within a shorter
period ensuring uniform cropping, This is
very important when the fruit is grown
and time of flowering In the plants with hormones
has been found to be enhanced flowering The response of the plants to
hormone treatment varied according to the substances used and their
concentration* Other effects of hormone treatment have been found to
be increase in size and weight of the fruit.

Bamboo
42 BANO BIGGY-‘N PATRIKA
i Revised version of the paper presented at the Third Annual Bangladesh Science
blight causing severe mortality, particularly of young
culms, in the village groves of Rajshahi district of Bangladesh is
reported. A brief history of the outbreak of the disease is noted,
A review of bamboo diseases is provided. Symptoms and observed
mode of infections are recorded. Four fungi have been isolated from
diseased bamboo samples. The pattern of isolation strongly suggests
that Conlothyrium fuckelil Sacc. is responsible for the blight.