http://www.digital.lib.esn.ac.lk//handle/123456789/1256 Tue, 07 Apr 2026 13:03:12 GMT 2026-04-07T13:03:12Z http://www.digital.lib.esn.ac.lk//handle/123456789/1720 Principal component analysis (PCA) of morphometric data taken from the opistheptoral hard parts of Dactylogyrus vastator Nybelin, 1924 (Monogenea) reared at three experimental temperature P.Vinobaba Dactylogyrus vastator Nybelin, 1924 is a common economically significant pathogenic gill parasite ofCyprinus carpio. D. vastator attaches to gills by means of an attachment organ, the opisthaptor, which carries two large hamuli, a connecting bar and fourteen marginal hooks. Principal component analysis (PCA) is a multivariate analysis using morphometric data used to separate morphologically close species on the basis of considering all the measured variables simultaneously and loading for differences between the specimens. Principal component analysis was used to investigate the effects of temperature on sclerite measurements.This study was carried out to stress the morphological variation or discrimination from the measured variables of D. vastator reared at three different water temperatures using PCA.The measured variables such as spike length of the hamuli, outer root length of the right hamuli, and internal root length are major factors which clusters more than 75.0% within the eclipse by which the population of the parasite reared at different temperature regimes will be discriminated. The length measurements clusters and fall within the eclipse, the eclipse of different temperature will be separated off very'clearly for the 12°C reared specimens than those reared at 14°C and 19°C. Mon, 01 Jan 2007 00:00:00 GMT http://www.digital.lib.esn.ac.lk//handle/123456789/1720 2007-01-01T00:00:00Z http://www.digital.lib.esn.ac.lk//handle/123456789/1716 Vulnerability to stem xylem cavitations in three Eucalyptus spp.clones of 14 months old at two water regimes P.Manoharan, N.W.Pammenter The response of three Eucalyptus spp. clones (GC550, GU2IO and TAG 14) to soil moisture condition was assessed by means of plant water status, leaf gas exchange and stem xylem vulnerability. Data for 14 months old grown in 25 I pots clones were collected on the diurnal variation in leaf water potential (if/J, stomatal conductance (gj and net CO, assimilation rate (A). Main stem xylem vulnerability was assessed using ultrasonic acoustic emissions (LJAE). Vulnerability of the main stem was assessed as the leaf water potential corresponding to the maximum rate of acoustic emissions (y/,, EPHniar), and as the critical water potential triggering cavitation events, calculated as the mean of the water potentials of data points lying between 5 and 10% of the total accumulated emissions (cUAE,%). Early stomatal closure was apparent, maintaining l constant during the middle of the day in all clones. Stem xylem vulnerability, assessed as both y//,EPHimn and y/(.4l.cUAE,% showed that the main stem of GC550 was more vulnerable than other two clones, and that low watered plants were more resistant to xylem cavitation than those receiving high water. Midday y/f fell below the vulnerability values assessed by both measures across treatments and clones, suggesting lack of stomatal control preventing stem xylem cavitation. Mon, 01 Jan 2007 00:00:00 GMT http://www.digital.lib.esn.ac.lk//handle/123456789/1716 2007-01-01T00:00:00Z http://www.digital.lib.esn.ac.lk//handle/123456789/1714 Interconnectivities of processes in the Earth System: A case study on the influences of Mt.Pinatubo eruption in June 1991 as a possible stochastic catalytic trigger on increased terrestrial vegetation resilience to the ENSO M.Manobavan Inter connectivities in the Earth System, between physical and vegetative elements are explored using the Mt. Pinatubo eruption as a focal point in this paper. Simulations performed using the Hybridv4.1, a mechanistic simulation model that is capable of mimicking vegetation processes suggest the possibilities of teleconnective loops between volcanic eruptions and vegetation response via climatic changes. This leads to the speculation/conclusion that the Earth System's behaviour could be ex plained using arguments developed based on the Gala concept. Mon, 01 Jan 2007 00:00:00 GMT http://www.digital.lib.esn.ac.lk//handle/123456789/1714 2007-01-01T00:00:00Z http://www.digital.lib.esn.ac.lk//handle/123456789/1713 Antigestational effect of Icon ®, a parathyroid insecticide on late pregnancy of rats S.S.K. Ratnayake, W.D. Ratnasooriya; Y.N.A. Jayatunga Icon* is a type II synthetic pyrethroid insecticide based on active ingredient Lambda cyhalothrin (10% w/w) and used as an adulticidal indoor spray against malaria vector mosquitoes in Sri Lanka. The purpose of this study was to review the effects of Icon" on pregnancy outcome oj rats when exposed during late pregnancy (days 15-21). Icon' was orally administered for 7 consecutive days in three different doses 63, 83, or 125 mg/kg/day respectively. Oral exposure to Icon" during late pregnancy was detrimental to pregnancy outcome (in terms of number of viable pups, gestation index, live birth index, pups survival ratio, viability index) and developmental parameters of pups (such as body weight, cranial length, cranial diameter, tail length, cranial - sacral length and viability at postnatal day I) but induced no detectable congenital malformations. Further, there was a significant prolongation of pregnancy. The mechanism of Icon" induced deaths and growth retardation of foetuses appear to be due to Intra Uterine Growth Retardation (IUGR) mediated by a combination of specific and non specific modes of actions such as reduced food consumption, maternal and embryo/foetotoxicity, stress and uterotropic activity. Mon, 01 Jan 2007 00:00:00 GMT http://www.digital.lib.esn.ac.lk//handle/123456789/1713 2007-01-01T00:00:00Z