Computational study of crystallography, defects, ion migra-2 tion and dopants in almandine garnet

Almandine garnet has received considerable amounts of interest due to its application in manufacturing and engineering processes. Defect processes, Fe-ion diffusion pathways, and promising dopants on the Al, Fe, and Si sites are examined using classical pair potential simulations in almandine garnet. The cation antisite (Al–Si) defect cluster is the most favourable defect, highlighting the cation disorder in this material. A three-dimensional long-range Fe-ion diffusion pathway with an activation energy of 0.44 eV suggests that the ionic conductivity in this material is high. The most favourable isovalent dopants on the Fe, Al, and Si sites were found to be the Mn, Ga, and Ge, respectively. Subvalent doping of Ga on the Si site is a favourable process to increase the Fe content in this material

EFFECT OF DIFFERENT LEVELS OF SALINITY ON SEED GERMINATION OF FOUR SELECTED TREE SPECIES

Salinity is one of the most adverse factors, which restrict the economic utilization of availableland resources in the dry zone of Sri Lanka. The salt affected area in Sri Lanka is estimatedabout 223,000 ha, which comprises 3% of the land area of the Island, found mainly in the dryzone (Vivekanandan, 1989). The most of the salt affected lands are generally barren, with littlewoody vegetation of salt tolerant bushes and herbaceous flora. This resulted in serious soilerosion and land degradation problems, which spreads into adjoining productive agriculturallands too. Therefore it is very important to restore these lands for useful agricultural purposes. Inthis context, the present study was mainly focused to determine the effect of salinity on seedgermination of four selected tree species, namely Castor (Ricinus communis), Ipil-ipil (Leucenealeucocephala), Wood apple (Feronia limonia) and Kottamba (Terminalia catappa) in order tostudy the possibility to regenerate these tree species by direct seeding in salt affected lands.Four separate pot experiments were conducted by using above four tree species in sand trays. Allexperiments were arranged in a Complete Randomized Design with 5 replicates. 100 seeds wereplanted in each tray for germination. Trays were kept moist with different levels of saline water(i.e. 0.13 (normal water) 4, 8, 12, 16, 24, 32, and 40 (Seawater) mmhos/cm) by diluting seawateras assigned in different treatments throughout the experimental period.Result revealed that seed germination in control treatments was higher in Wood apple (100%)and Castor (72%) than Kottamba (31%) and Ipil-ipil (13%). Seed germination was decreasedwith increasing level of saline level in Kottamba and Castor. In Kottamba, no germination wasobserved at all when at salinity level increased up tc 16 mmhos/cm while in Castor germinationwas nil when salinity level increased up to 40mmhos/cm. In Wood apple, more than 80% ofgermination was recorded even up to the salinity level of 24 mmhos/cm. Germination was poorin Ipil-ipil even in control treatment and not significantly decreased up to the salinity level of 40mmhos/cmTherefore, the species can be ranked in order to tolerance to salinity in terms of germination asfollows: Ipil-ipil>Wood apple>Castor>Kottamba.

IDENTIFYING AND MAPPING SALT-AFFECTED LANDS IN HAMBANTOTA DISTRICT, SRI LANKA: AN INTEGRATED GIS AND REMOTE SENSING APPROACH

Since available lands in Sri Lanka is decreasing every year mainly due to degradation oflands, it is very important to restore these lands for useful agricultural production. In thisregard, identification of salt-affected lands and differentiates into salinity levels wouldhelp to take necessary actions to restore these lands.An extensive soil survey was conducted throughout the Hambantota district in order to10 0 to to KA•••••.•.identify the salt-affected lands in the district The sampling was done at different depths(i.e. O-lOcm, IO-20cm, 20-30cm, 30-4Ocm and 40-50cm) by using a manual soil auger.The distance between sampling sites was approximately 3km. The exact position ofsampling points in latitude and longitl!c!~ ~ identified by GP~ (Global PositioningSystea), A total number of 100 points and 400 samples were collected. Topographicmaps of survey of Sri Lanka used in the study were Timbolketiya (82), Kataragama(83),Yala(l4), Hambantota(88) and Tissamaharama(89) of scale 1:50,000. Digital thematicmaps of same map sheets and Scale of I :25000 digital maps were also been used.The samples were taken to the laboratory of the Department of Crop Science, Faculty ofAgriallture, University of Ruhuna, where EC and pH measurements were taken using theEC meter and the pH meter. AIl the locational data taken using GPS system, entered intoa database. EC and pH data also been entered to the database. Using ArcView software, apoint map was generated using all the locational data including EC and pH values asattribstes. By applying interpolating techniques, salinity maps were produced.

Salacia reticulata wight: a review of botany phytochemistry and pharmacology.”

ABSTRACT Salacia reticulata is a large woody climbing shrub naturally found in Sri Lanka and Southern region of India. It is widely used in treating diabetes, a chronic disorder in metabolism of carbohydrates, proteins and fat due to absolute or relative deficiency of insulin secretion with/without varying degree of insulin resistance. The decoction of S. reticulata roots is also used in the treatment of gonorrhea, rheumatism, skin diseases, haemorrhoids, itching and swelling, asthma, thirst, amenorrhea and dysmenorrheal. Presence of mangiferin (a xanthone from the roots), kotalanol and salacinol (from the roots and stems) have been identified as the antidiabetic principles of S. reticulata. Chemical constituents such as 1,3-diketones, dulcitol and leucopelargonidin, iguesterin, epicatechin, phlobatannin and glycosidal tannins, triterpenes, and 30-hydroxy-20(30) dihydroisoiguesterin, hydroxyferruginol, lambertic acid, kotalagenin 16-acetate, 26-hydroxy-1,3-friedelanedione, maytenfolic acid have also been detected in the roots of S. reticulata. The antidiabetic property of Salacia is basically attributed to the inhibitory activity of intestinal enzymes (α-glucosidase and α-amylase). Inhibition of intestinal enzymes delays glucose absorption into the blood and suppresses postprandial hyperglycemia, resulting in improved glycemic control. Furthermore, mangiferin has been reported to inhibit aldose reductase activity delaying the onset or progression of diabetic complications. Though diabetes has now become an epidemic affecting millions of people worldwide, neither insulin nor other modern pharmaceuticals has been shown to modify the course of diabetic complications mainly due to the multifactorial basis that involves both genetic and environmental risk factors. Therefore, effort is being devoted to find new therapeutics aimed at multiple targets, which has become a new paradigm in drug discovery. In this context, the discoveries on S. reticulata have lead to increase the consumption of the species across the world and it has now become a subject of broad studies for diabetes management

EFFECT OF DIFFERENT LEVELS OF SALINITY ON GROWTH PERFORMANCES OF FOUR SELECTED TREE SPECIES

Salt affected soils are widespread in different parts of the world. In recent years significantamount of land extent were affected due to salinity rendering them biologically unproductive.The use of specific techniques for tnc amelioration of these lands for agriculture is taking placecontinuously. Reforestation of salt affected soils is possible given proper site preparation, choiceof suitable salt tolerant species and their proper nursery and cultural practices are achieved. Thepotentials of these soils for growing trees and woody vegetation have not been fully exploredyet.Therefore, four different pot experiments were conducted by using four selected tree speciesmainly available in the salt affected areas (i.e, Tamarind (Tamarindus indica), Katuandara(At:acia /eucop/oea), Castor (Ricinus communis) and Wood apple (Feronia /imonia) at theFaculty of Agriculture, University of Ruhuna Mapalana, Kamburupitiya during April to October200 1 to assess the influences of different levels of saline water (i.e. 0.13,2,4,6,8 and 12mmhos/cm) on growth and development of above four tree species. All the experiments wereconducted by using a Randomized Complete Design with four replicates. One month oldseedling raised in 6"x8" size polythene bags were used for the experiment. Seedlings weretransferred to lager Polythine bags (lO"x 12") at 2 months after planning without damage to theroot system to ensure enough space for root development. Plant height, shoot and root biomassyield were measured at every 2 weeks interval.The result revealed that the plant height, shoot and root biomass yield were not affectedsignificantly by different levels of saline water up to 12 mmhos /cm compared to the controlwhere normal water (O.13mmhosl em) is applied in all crop species. Therefore all four-treespecies, which were used for the experiment, may be recommended as salt tolerant tree speciesup salinity to the level of 12rnmhos/cm.

CONSTRUCTION OF A GROWTH MODEL TO PR~DICT THE INDIVIDUAL STEM VOLUME OF Eucalyptus grandis HILL EX MAIDEN (TOOLUR) IN SRI LANKA

Toolur (Eucalyptus gram/is Hill ex Maiden) belongs to family Myrtaceae has been plantedwidely in the hill country of Sri Lanka for high quality timber and fuel wood. For thepresent study a growth model was constructed to predict the total stem volume ofindividual toolur trees. Data were obtained using temporally sampled plots from the treeplantations in Badulla forest division and 6 plalltations.~:. Nuwara-Eliya forest division.Data were first partitioned according to the quality of the site. An index developed using atop height / plantation age was used for site classification and three significantly differentsites could be identified. In order to construct the model, 75% of sample plots from eachplantation was used and the rest was reserved for the purpose of validating the constructedmodel with independent data.The basic model structure was developed using the relationship between volume and formfactor, basal area and total height. Form factor is difficult to measure because it varies withage, site quality, depsHyetc. ~ven!or the same species. Therefore keeping the other twovariables, it was tried to replacctii.cfortnfactQLH~ing. other explanatory variables, whichcan be measured easily.All possible combinations of the explanatory variables were tested ill order to obtain thebest models. The performance of the models was observed using statistical tests andstandard residual distributions. For the selected models, the intercept was not significantlydifferent from zero and number of trees per hectare and total basal area tested to representthe stand density was also not significant.After selecting the four suitable models at the first stage, the possibility of using one set ofparameters instead of separate parameters sets for different site types was tested. First theparameters were estimated for the pooled 'data. Using the resulted models, normal residualswere calculated separately for three site types. Then the significance of the residuals wastested using analysis of variance for select the final model with common set of parameters.A selected model contained basal area and total height Q~ individual trees and a site qualityfactor as explanatory variables. It was then compared -directly with the particular observedvalues. After all the tests, the results indicated that tile model coustructed in this studyproved its strength on predicting the total volume of individual stems precisely because itindicated a very low bias and a high modeling efficiency of over 0.09.The resultant model which can be used to predict the individual toolur stem volume for allsite types is:(Volume/12=0.5946*(basal area * total height )1/2 + O.0356*(total basal area / lop height).

SUCCESSFUL ACCLIMATIZATION OF IN-VITRO ROOTED STEM CUTTINGS OF CINNAMON (Cinnamomum verum Presl)

Hardening of regenerated plantlets for successful field transfer is consideredto be a major obstacle in clonal micro-propagation of cinnamon. In-vitroinduced roots are rarely functional, lack of root hairs, fragile and aregenerally damaged during transfer to the soil. Therefore, objectives of presentexperiments were to develop an appropriate acclimatization procedure and toselect a suitable potting media for successful field establishment of Cinnamon plantlets.In-vitro rooted stem cuttings were transferred in to four different pottingmedia of Soil, Coir dust, Sand: Coir dust - (1: 1) and Soil: Sand - (1: 1)Sealed containers with sterilized potting media were used to maintain >80 %Relative humidity for 2 weeks and then gradually acclimatized to fieldconditions. Three different procedures (1) lid removed and kept in shade after2 weeks of transplanting (2) lid removed only at nights after 2 weeks oftransplanting, and (3) lid removed after 4 weeks of transplanting were used astreatments.At the end of 4th week, plantlets in coir dust medium showed the highestsurvival rate (87.5 %). Higher number of new leaf formation was observed incoir dust medium and overall appearance of the plantlets was very good.Most plantlets in soil medium were dead at the end of the 4th week, andremaining plantlets were very weak. Acclimatization procedure did notsignificantly affect on growth or overall appearance of plantlets. Resultsrevealed that coir dust medium provided with two weeks of humid conditionsis the best for successful acclimatization of in-vitro Cinnamon plantlets

EFFECT OF DIAMETER ON VOLUME MEASUREMENTS OF Pinus caribaea (MORELET).

is the most important parameter in commercial forestry especially at themature stage. Among those methods, the most common way is to useSmalian's, Huber's and Newton's formulae. In order to use these threeformulae the stem should be divided into sections and volume of each sectionshould be determined separately. Huber's formula is the easiest one to usebecause it needs only one diameter measurement of the log. Smalian'sformula needs two diameter measurements while Newton's formula needsthree. Log length is required for all three formulae. Due to the low number ofmeasurements Huber's formula is more popular among the foresters.However, Smalian's and Huber's formulae can introduce errors because theyuse fewer measurements compared to the Newton's formula. Therefore thepresent study was conducted to identify the variation of the error withincreasing diameter of trees when Huber's and Smalian' s formulae are used.Newton's formula was considered as the one that provides precise values involume estimation.Present study was conducted in the 26 year old Pinus caribaea plantation inYagirala Forest Reserve situated in the low country wet zone of Sri Lanka. Inorder to represent the whole area of the forest, stratified random samplingmethod was used and one O.OSha sample plot was laid in each stratum (i.e.,valley, slope and ridge).Each tree of the plot was divided into twelve 1m long sections using aranging staff. Bottom, mid and top diameter of the each section wasmeasured using the Spiegal relascope. Other than above measurements,diameter at the breast height and height of the tree were measured using thediameter tape and the Blume Leiss Altimeter respectively.In order to find out whether the diameter at breast height affected on volumecalculations using above formulae, trees were grouped into two centimeterdiameter classes. At each diameter class, volumes estimated using Huber'sformula were tested separately for different section lengths using one wayANa vA. Results indicated that at 95% probability level diameter does not have a significant influence in volume measurements for Huber's formula upto twelve meter stem length.First part of this study was conducted to identify the effect of Huber's andSmalian's formula in volume calculations without considering the diameterdifferences of trees in the forest and results proved that Huber's formulaproduced least errors when compared with Smalian's formula. However, inthis instance the maximum stem length that can be measured using Huber'sformula became 6m. According to both tests, it can be concluded thatHuber's formula can be use effectively up to 6m stem length in volumecalculations with out considering the diameter range of trees

GROWTH PERFORMANCES OF CASHEW NUT (Anacamium occidentale L) AND RANAWARA (Accasia auriculata L) UNDER DIFFERENT LEVELS OF SAUNITY

There are large extents of salt affected lands in Sri Lanka, which is estimated to be'223,000 hectares or about 3% of land area of the island, mainly in dry zone areas. Thisseverely affect the productivity of the agricultural lands. And selection of salt-toleranttreelcrop species is considered to be one of the alternatives to overcome this problem.Two separate pot experiments were conducted to study the effect of different salinitylevels on growth performances of cashew nut (Anacardium occidentale L) and Ranawara(Aceasia aurieulata L) at the Faculty of Agriculture, Mapalana. Each tree speciesconsisted of eight treatments, which were differentiated, with different concentrations ofsalinity (i.e. 0, 2, 4, 6, 8, 12, 16, 20mmhos/cm). The experimental design for bothexperiments were Complete Randomized Design (CRD) with 4 replicates. One month oldplants raised in poly bags (10" x-Iz") were used to apply different treatments. 100 ml ofsaline water, which, was prepared by diluting sea water in different treatments wasapplied twice a week. Plant height and the dry matter yield of shoots and roots weremeasured at 3, 6, and 9 weeks after the treatment applicationThe results revealed that plant height, shoot and root biomass has decreased Significantlywith increasing levels of saline water up to 12mmhoslcm compared to the control wherenormal water (O.13mmhoslcm) is applied in cashew nut. Ranawara seems to be more salttolerant. At the early stage, shoot height. shoot weight and root weight significantlydecreased with increasing level of salinity but at latter stage they were not much affectedwith increasing level of salinity. Therefore Ranawara could be recommended as mediumsalt tolerant tree species while cashew nut is not much tolerant to salinity.

Rapid onset of action of costus speciosus leaf extracts on insulin resistance in experimental wistar rats

Objectives: To evaluate the effect of Costus speciosusleaf methanol and water extracts on insulin resistance. Methods: Male rats were divided into five groups (n=6) and IR was induced by high fat diet (19.13% fats). CS leaf methanol extract (CSlmex) and water extract (CSlwex) were prepared using standard methods. Rats were treated daily for 30 days. Group1: 0.5% Carboxy methyl cellulose (CMC) 1ml, Group2: 500 mg/kg/day CSlmex in CMC, Group3: 500 mg/kg/day CSlwex, Group4: 1500 mg/kg/day CSlwex, Group5: Pioglitazone 10mg/kg/day. Serum was analysed for glucose, triglycerides and insulin at baseline and after one month. IR was calculated using indirect indices; HOMA, QUICKI and McAuley (McA). Results: All CS extracts significantly reduced the IR (p<0.05). 500mg/kg CSlmex reduced IR by HOMA, QUICKI, McA by 61.3%, 15.6%, 39.8% while 1500mg/kg CSlwex reduced HOMA by 66.6%, QUICKI by 16.1% and McA by 36.5% respectively. There was no significant change of IR in CMC group (p>0.05).IR had been reduced by pioglitazone (HOMA 32.4%, QUICKI 12.5%, McA 10%) after one month but not statistically significant (p>0.05). Conclusion: CS leaf water and methanol extracts are effective on reducing IR in rats. Pioglitazone was used as the positive control. Previous scientists had shown that pioglitazone needs minimum of three months to make a significant therapeutic effect on IR although pharmacological effect appears after one month. Our finding shows that CS may have a rapid onset of action on IR based on our biochemical evidence compared to pioglitazone. Therefore, pharmacodynamic studies are recommended to evaluate the dose response relationship.