Explosion pulping of eucalyptus: a comparison with CTMP and CMP

Summary Explosion pulping results in strong pulp with breaking length at 100 ml CSF (Canadian standard freeness) higher than 6.5 kg and burst index approaching 4 KPa m²/g. The real advantage of eucalyptus explosion pulp over conventional CMP (chemical-mechanical pulp) and CTMP (chemical-thermo-mechanical pulp) is observed when the impregnation solution contains less than 2% NaOH along with 8% Na₂SO₃, and when the liquor/chips ratio equals 3. The strength of eucalyptus explosion pulp obtained by using a pretreatment solution consisting of 8% Na₂SO₃ and 1% NaOH is comparable with that of eucalyptus kraft pulp. The concentration of NaOH present in the pretreatment solution has a very important effect on the specific refining energy of eucalyptus explosion pulp as well as of CMP and CTMP. The explosion pulp obtained from eucalyptus pretreated with a solution containing an appropriate quantity of caustic along with Na₂SO₃ not only requires a minimum specific refining energy but also provides the highest strength values in comparison to that of CMP and CTMP.     

Zum saisonalen Auftreten der Baumwolleule,Spodoptera littoralis (Boisd.) (Lep., Noctuidae) und ihrer Kernpolyedrose (NPV) in verschiedenen Distrikten Ägyptens

Infection rates of the nuclear polyhedrosis virus (NPV) in the cotton leafworm,Spodoptera littoralis larvae were assessed from 1985 through 1986 in clover fields at El-Behiera, El-Fayoum and El-Gharbia governorates. Infection rates of the pathogen were highest near the end of spring when the cotton leafworm larval populations were increasing. For the different governorates, the percentages of virus infection were almost higher in 1985-season than in 1986. El-Fayoum-larval population was the most infected by NPV followed by El-Gharbia and El-Behiera-populations, respectively. There was a positive correlation between infection rates of NPV on one hand, and density of larva and ambient temperature on the other.     

Agroforestry: a viable land use of alkali soils

A system of land use of alkaline wastelands of the Indo-Gangetic plain has been proposed consisting of planting Prosopis juliflora, a multi-purpose tree species, with the objectives of economic return as well as soil amelioration. Tree farming onalkaline wastelands provides not only fuel, fodder, timber and income to the rural population but also shows good effects in improving the soil characteristics. The detailed costs of such an agroforestry system on alkali soils have been worked out and the mean annual production of Prosopis juliflora on soils of different pH have been analysed. In spite of the high cost of establishing a plantation, an economic analysis of the system yields a 9.5% internal rate of return which is reasonably high for degraded lands of strongly alkali soils and also viable within the economic structure of the region.     

Chemical composition,antioxidant and antibacterial activities of extracts from <Emphasis Type="Italic">Schinus molle</Emphasis> wood branch growing in Egypt

In the present work, for the first time, the chemical components of essential oils (EOs) and extracts from wood branch (WB) resulted from the tree pruning wastes of Schinus molle L. grown in Egypt were evaluated for their antioxidant and antibacterial activities. EOs, methanol (ME), dichloromethane (DCME) and water (WE) extracts as antioxidant and antibacterial activities were measured. Total phenolic and flavonoid contents as well as analysis of extracts by gas chromatography–mass spectrometry (GC–MS) were reported. The major components in EOs were α-elemol, β-pinene, and α-phellandrene, in ME were 6-(4-chlorophenyl)-3-cyano-4-(N-benzylpiperazino)-2H-pyran-2-one, and 2-naphthalene methanol, decahydro-α,α,4a-trimethyl-8-methylene, in DCME were 12-methyl-E,E-3,13-octadecadien-1-ol, and 1,2-benzenedicarboxylic acid, dioctyl ester, and in WE were β-eudesmol, and (Z,Z,Z)-9,12,15-octadecatrienoic acid, 2,3-dihydroxypropyl ester. The highest total antioxidant activity was found with EOs (90 ± 1.23 %) and WE (86.30 ± 1.40 %). The lowest IC₅₀ values of 13.11 ± 3.00, and 12.66 ± 2.15 μg/mL were found with WE and EOs, respectively. EOs and WE were observed to have good antibacterial activity against Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Sarcina lutea, Pseudomonas aeruginosa, and Micrococcus luteus. In conclusion, the Schinus molle L. WB EOs and extracts might, indeed, be used as a potential source for pharmaceutical or food industries.     

Bioactive constituents of Leptadenia arborea

The aerial part of Leptadenia arborea has been shown to contain pinoresinol (1), syringaresinol (2), leucanthemitol (3) and E-ferulaldehyde (4). These known compounds are being reported for the first time from this plant. Among them, syringaresinol has shown an inhibitory effect against acetylcholinesterase. The IC(50) (the concentration of 50% enzyme inhibition) value of this compound was 200 microg/ml.     

A new eudesmanolide from Crataegus flava fruits.

A new eudesmanolide, 1beta,9alpha-dihydroxyeudesm-3-en-5beta,6alpha,7alpha,11alphaH-12,6-olide (1), was isolated from Crataegus flava fruits. Its structure was determined by spectroscopic methods.     

Evaluation of pulp and paper making characteristics of certain fast growing plants

Summary Four species of fast growing annual plant viz.Hibiscus sabdariffa, Crotalaria juncea, Tephrosia candida andHibiscus cannabinus and a variety of reed, Neyraudia reynaudiana were evaluated in the laboratory for their pulp and paper making properties. Data on proximate chemical analysis of raw materials, unbleached and bleached pulp properties, morphological properties of fibres and physical strength properties of paper sheets were evaluated. The unbleached pulp yields were 44.90–53.20% with all the five plant materials, while bleached pulp yields varied from 39.80–50.60%. The average fibre lengths and diameters of the unbleached pulp obtained from the five plant species were within the range of 0.75 mm–2.15 mm and 20–22 pun respectively. Paper hand sheets, made with bleached pulps (45° SR) obtained from the five plant species, gave burst indices 2.75–3.92 kPa m²/g, tear indices 3.73–9.61 m N m²/g and tensile indices 37.27–47.81 N mg^–1, indicating adequate strength properties for writing and printing type of paper.The authors thank Director, Regional Research Laboratory (CSIR), Jorhat, India, for his kind permission to publish this paper. The authors also wish to thank B. N. Tosh, JPF for his assistance.     

Effects of leaf area and auxin on rooting and growth of rooted stem cuttings of neem

Green stem cuttings, obtained from 2-year old managed stockplants, with 30, 50 or 100% leaf area were rooted in a non-mist propagator following treatment with 0, 0.2, 0.4 or 0.8% IBA solution. The rooted cuttings were transferred to polythene pots and grown in a nursery for 12 weeks. Rooting percentages of IBA treated cuttings did not significantly differ from those of control cuttings. Likewise leaf area did not significantly influence the percentage of cuttings that rooted. The effects of leaf area and/or IBA treatment in the propagation unit were manifested on the growth of rooted cuttings in polythene pots. Number of roots increased with the increase in IBA concentration and this response was enhanced by increasing leaf area. Root biomass increased with the increase in leaf area even in the control cuttings. Root development was highly influenced by the leaf area and IBA, and hence the growth of rooted cuttings. Cuttings treated with 0.2 or 0.4% IBA at 100% leaf area yielded the best performing rooted cuttings.     

Bacteria wilt of Casuarina equisetifolia in India

Pseudomonas solanacearum (Smith) was consistently isolated from the wilted plants of Casuarina equisetifolia. The isolate gave positive reaction to oxidase, catalase and gas production from nitrate and negative reaction for arginine dihydrolase and acid was produced from various carbohydrates. Wilt produced on tomato, egg plant and capsicum indicated that the pathogen belongs to Race I and Biovar III of P. solanacearum which is a new record from India.     

People’s attitude and use of forestland: Co-evolution of forest administration in Bangladesh

This paper explores the influence over time of past policies on people’s attitudes towards the use of forestland in Bangladesh. The discourses of the attitudes of people were captured from the observed social tradition towards forest resources. Forests were reserved systematically and solely through the Forest Department. The conservation processes were not participatory, and rights and tenure were strictly controlled. People were socially excluded and alienated from the forest, and the socio-political factors stimulated negative attitudes among people. Forests were considered to be government property, and therefore managing forests was the responsibility of the government. People only used forest resources to meet their own requirements, either with formal permission or illegally. This situation continued even after the independence of Bangladesh in 1971. As a result, the forests of Bangladesh have been degraded heavily in recent decades.