Showing papers on "Excoecaria agallocha published in 1997"
TL;DR: Within the estuary mouth, above-ground biomass of Avicennia marina and Ceriops tagal decreased between frontal saline and upper-intertidal hypersaline environments, and this was reflected in the below-ground : above- ground biomass ratios, which increased to approximately 3.5 for both species.
Abstract: Above- and below-ground biomass of five species of mangroves was estimated for the Mary River, south-eastern Queensland. Below-ground : above-ground biomass ratios of species in the upstream reaches (Avicennia marina, Aegiceras corniculatum and Excoecaria agallocha) averaged <0.5, and those of species in the saline conditions of the mouth (Avicennia marina, Rhizophora stylosa) ranged between 0.9 and 1.5. Within the estuary mouth, above-ground biomass of Avicennia marina and Ceriops tagal decreased between frontal saline and upper-intertidal hypersaline environments, and this was reflected in the below-ground : above-ground biomass ratios, which increased to approximately 3.5 for both species.
53 citations
TL;DR: In this article, the authors investigated the distribution and characterization of remaining mangrove stands in Hong Kong and found that 43 mangroves still remained along the coastline of Hong Kong despite tremendous reclamation and development which occurred in the past 40 years.
Abstract: Ecological surveys were carried out to investigate the distribution and characterization of remaining mangrove stands in Hong Kong The field studies indicate that 43 mangrove stands, excluding Mai Po Nature Reserve, still remained along the coastline of Hong Kong despite tremendous reclamation and development which occurred in the past 40 years Most mangrove stands were found in Deep Bay (western part) and Sai Kung District (eastern coasts) The total areas occupied by these mangrove stands were 178 ha, varying from a very small stand (with 1–2 mangrove shrubs) to fairly extensive mangroves in Deep Bay (> 10 ha) It appeared that mangrove stands located in Deep Bay area were larger than those in the eastern coasts Twenty plant species were identified from these stands, with 13 being exclusive or associate mangrove species The major constituent species were Kandelia candel, Aegiceras corniculatum, Excoecaria agallocha and Avicennia marina Rare species such as Heritiera littoralis were only found in a few mangrove stands Out of the 43 remaining mangrove stands, 23 were more worthwhile for conservation and their plant community structures were further investigated by transect and quadrat analyses The importance values (sum of relative abundance, frequency and dominance) show that K candel was the most dominant species Species richness and Simpson’s indices together with tree height, tree density and canopy area fluctuated significantly between mangrove stands These values were used to prioritize the conservation potential of the remaining mangrove stands in Hong Kong
43 citations
29 Apr 1997
TL;DR: Plant samples were collected from 15 mangrove species and extracts were tested for their activity against the larvae of mosquito, Culex quinquefasciatus, and petroleum ether extract of R. apiculata was found most effective with LC 50 of 25.7 mg/l.
Abstract: Plant samples were collected from 15 mangrove species, Acanthus ilicifolius, Aegiceras corniculatum, Avicennia marina. A. officinalis, Bruguiera cylindrica, Ceriops decandra, Excoecaria agallocha, Rhizophora apiculata, R. Lamarckii, R. mucronata, Salicornia brachiata, Sesuvium portulacastrum, Sonneratia apetala, Suaeda maritima, S. monoica and Xylocarpus granatum. The 22 samples were extracted in acetone and petroleum ether separately, and the extracts were tested for their activity against the larvae of mosquito, Culex quinquefasciatus. Petroleum ether extract of R. apiculata was found most effective with LC 50 of 25.7 mg/l. The extract was studied further with pyrethrum for its synergistic larvicidal activity. The extract exhibited synergism and the synergistic factor was 0.81 at 5 mg/l.
33 citations
TL;DR: In this paper, a set of mangrove trees were propagated and planted over 10 ha of degraded salt-marshy wetlands of Mahanadi delta inpure and mixed stands depending on the intensity and the frequency of tidal flooding at the experimental site.
Abstract: In India, mangroves occupy 6740 km2 of which the Mahanadi delta andBhitarkanika mangrove forests of Orissa cover 191.44 km2, most of whichhas been severely overexploited. World wide concern to conserve mangrovesnecessitated propagation of mangroves to re-establish them on barren andswampy land along tidal creeks around Paradeep port of Orissa. Avicenniaofficinalis, Aegiceras corniculatum, Bruguiera parviflora, B. sexangula,Ceriops decandra, Excoecaria agallocha, Heritiera fomes, Kandelia candel,Rhizophora mucronata, Sonneratia apetala were vegetatively propagated andplanted over 10 ha of degraded salt-marshy wetlands of Mahanadi delta inpure and mixed stands depending on the intensity and the frequency of tidalinundation at the experimental site. Survival was significantly higher(80%) in S. apetala followed by A. officinalis, R. mucronata, K.candel and H. fomes (70–75%). S. apetala recorded the maximumgrowth in height (3.0 m after 2 years) whereas C. decandra showed theminimum growth (0.5 m). Growth performance was better with plants in mixedstands than the plantation with single species. This gives us hope topropagate and re-establish mangroves for conservation in scientificallymanaged plantations in a physiologically arid environment.
27 citations
TL;DR: By analysis for the natural stable carbon isotoperatios, it was possible to establish the primary carbon source from the mangroves to that of larvae and juveniles of P. indicus and P. monodon, which can be used to exploit theMangrove habitat as prawnnurseries.
Abstract: The Godavari estuarine system extending over approximately 316 km2 has significant annual variation of salinity due to seasonal flooding which is mainly monsoon fed. This area has dense vegetation of mangroves and is characterised by predominance of Avicennia sp. Excoecaria agallocha and Rhizophora sp. In the coastal waters adjacent to the mangroves three economically important species of prawns occur (Penaeus monodon, P. indicus and Metapenaeus monoceros). Their larvae migrate and dwell in the mangrove environment. By analysis for the natural stable carbon isotope ratios, it was possible to establish the primary carbon source from the mangroves to that of larvae and juveniles of P. indicus and P. monodon. This information can be used to exploit the mangrove habitat as prawn nurseries.
22 citations
Journal Article•
15 citations
01 Oct 1997
TL;DR: In this paper, the authors describe investigations of the insecticidal compounds of three Sri Lankan plants, Pleurostylia opposita (Wall) Alston (Celastraceae), Aegle marmelos Correa (Rutaceae) and Excoecaria agallocha Linn.
Abstract: This thesis describes investigations of the insecticidal compounds of three Sri Lankan plants, Pleurostylia opposita (Wall) Alston (Celastraceae), Aegle marmelos Correa (Rutaceae) and Excoecaria agallocha Linn. (Euphorbiaceae). After establishing the insecticidal activity of the extracts of three plants, separation of compounds was achieved by bio-assay directed chromatography, and the compounds were characterised by NMR especially 2D experiments, mass, UV and IR spectroscopy.
Three new macrocyclic sesquiterpene polyol ester alkaloids 1, 2 and 3 containing a novel 6,7 ring skeleton have been identified from the petroleum ether-ethyl acetate extract of the stem bark of Pleurstylia opposita . They are homologues of known macrocyclic sesquiterpene alkaloids which contains a 6,6 ring system based on the s-dihydroagarofuran core. The extra methylene has been shown by NMR to be in the 8 position of the 6,7 ring. Observation of insecticidal activity in the Pleurostylia genus is novel. The previously reported 20-hydroxylupane-3- one has also been identified from the active extract and shown to be noninsecticidal.
Two new insecticidal compounds 6 and 7 have been identified from the petroleum ether-ethyl acetate extract of the stem bark of Aegle marmelos . They are shown to be protolimonoids, and are senecioate ester analogues of the known isovalerate esters of C-21-s and C-21-α glabretal which were also isolated. Compounds 8 and 9 were also found to be insecticidal against mustard beetles and houseflies. Separation and characterisation of epimeric mixtures were first achieved for the di p-nitrobenzoate derivative.
Previously recorded epoxyaurapten, marmesin, marmin and lupeol have been isolated from the active extract of Aegle marmelos and shown to be noninsecticidal.
Five compounds 24-28 have been isolated from the ethyl acetate extract of the stem bark of Excoecaria agallocha . They all have the previously reported daphnane diterpenoid orthoester skeleton, and differ only in the orthoester alkyl side chain. Two of them 24 and 27 are novel. Insecticidal activity has not been recorded previously for extracts of Excoecaria species, nor for the daphnane orthoesters.
6 citations
TL;DR: In this article, three new diterpenes, excoecarins A (2), B (3) and C (4), have been isolated from the wood of Excoecaria agallocha LINN.
Abstract: Three new diterpenes, excoecarins A (2), B (3) and C (4) have been isolated from the wood of Excoecaria agallocha LINN. The structures of excoecarins A, B and C were established as (13R, 14R)-ent-8α, 13;14, 15-diepoxy-13-epi-labda-3-one (2), (13R, 14S)-ent-8α, 13;14, 15-diepoxy-13-epi-labda-3-one (3), (13R, 14R)-ent-8α, 13;14, 15-diepoxy-13-epi-labda-3β-ol (4), respectively, on the basis of spectroscopic data and chemical evidence.