Reduced soil respiration in gaps in logged lowland dipterocarp forests   总被引：1，自引：0，他引：1  

Philippe Saner  Robin Lim  Bo Burla  Robert C. Ong  Michael Scherer-Lorenzen  Andy Hector 《Forest Ecology and Management》2009

We studied the effects of forest composition and structure, and related biotic and abiotic factors on soil respiration rates in a tropical logged forest in Malaysian Borneo. Forest stands were classified into gap, pioneer, non-pioneer and mixed (pioneer, non-pioneer and unclassified trees) based on the species composition of trees >10 cm diameter breast height. Soil respiration rates did not differ significantly between non-gap sites (1290 ± 210 mg CO₂ m⁻² h⁻¹) but were double those in gap sites (640 ± 130 mg CO₂ m⁻² h⁻¹). Post hoc analyses found that an increase in soil temperature and a decrease in litterfall and fine root biomass explained 72% of the difference between gap and non-gap sites. The significant decrease of soil respiration rates in gaps, irrespective of day or night time, suggests that autotrophic respiration may be an important contributor to total soil respiration in logged forests. We conclude that biosphere-atmosphere carbon exchange models in tropical systems should incorporate gap frequency and that future research in tropical forest should emphasize the contribution of autotrophic respiration to total soil respiration.  相似文献   

Performing ‘Chinese‐ness’ in Singkawang: Diasporic moorings,festivals and tourism          下载免费PDF全文

Chin Ee Ong  Meghann Ormond  Dian Sulianti 《Asia Pacific viewpoint》2017,58(1):41-56

Through an examination of two festivals – Qing Ming and Cap Go Meh – in the town of Singkawang in Indonesian Borneo (Kalimantan), we show how Singkawang‐bound Chinese Indonesian tourists and their Singkawang‐based relatives produce a diasporic heritage network through ‘moorings’ generated by both transnational and internal migration. Instead of returning to a singular ‘homeland’ in distant China, these tourists return to Chinese‐majority Singkawang as a result of their personal genealogical roots and of their broader cultural allegiance with a kind of Chinese‐ness that Singkawang has come to represent within a post‐Suharto Indonesia. Through these two festivals, we demonstrate how personal heritage practices like ‘roots tourism’ and visiting friends and relatives are intimately bound up with identity and developmental politics at local, national and international scales. In so doing, we identify a range of ways in which migratory and tourism flows by Chinese Indonesian internal migrants shape relations to their ancestral hometowns and cultural ‘homelands’ in Indonesia within the context of membership to and participation in a broader transnational diaspora.  相似文献   

Viral disease of tomato crops (Solanum lycopesicum L.): an overview     

Ong  Sheue Ni  Taheri  Sima  Othman  Rofina Yasmin  Teo  Chee How 《植物病害和植物保护杂志》2020,127(6):725-739

Journal of Plant Diseases and Protection - Global production of tomato has been hampered by the increased incidences of tomato viral disease. The high genetic heterogeneity of tomato plant viruses,...  相似文献   

Molecular characterization of a new 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR) transcript from Vanda Mimi Palmer     

Wai-Sun Chan  Janna Ong Abdullah  Parameswari Namasivayam  Maziah Mahmood 《Scientia Horticulturae》2009

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Dependence of aflatoxin in almonds on the type and amount of insect damage     

Schatzki TF  Ong MS 《Journal of agricultural and food chemistry》2001,49(9):4513-4519

The aflatoxin distribution of single insect damaged Nonpareil almonds (1999 crop) has been measured. Separate distributions were obtained for pinhole, insect (feeding), and gross damage. Only a low level of aflatoxin contamination ( = 0.0003 ng/g) was found for pinhole-only damaged nuts. The distributions for insect and gross damage did not differ, but did differ significantly from the distribution previously obtained for gross damaged Ne Plus almonds from a different producer (Schatzki, T. F.; Ong, M. S. J. Agric. Food Chem. 2000, 48, 489-492; also 1999 crop). The Nonpareil almond distribution could be explained on the basis of a preharvest hull splitting, similar to previous results in pistachios (0-4 weeks versus 2-6 weeks preharvest). The Ne Plus distribution differs in detail from pistachio results and from the Nonpareil results found here. This may indicate additional cultural damage of Ne Plus almonds around harvest time and/or use of different sorting parameters. Aflatoxin lot averages of 31.7 and 3.47 ng/g were obtained for 100% insect damaged Ne Plus and Nonpareil almonds, respectively. (The previous Ne Plus work contained a calculation error, which is corrected here.) The distribution functions were used to compute the seller's risk of nonacceptance of lots in the European Union. To obtain a 95% acceptance rate, aflatoxin B(1) levels of 0.12 and 0.22 ng/g would be required, which would correspond to 3.8 and 1.2% (feeding and gross) insect damage in Nonpareil and Ne Plus almond lots, respectively.  相似文献   

The distribution of important sero-complexes of flaviviruses in Malaysia     

Kumar  Kiven  Arshad  Siti Suri  Toung  Ooi Peck  Abba  Yusuf  Selvarajah  Gayathri Thevi  Abu  Jalila  A.R  Yasmin  Ong  Bee Lee  Bande  Faruku 《Tropical animal health and production》2019,51(3):495-506

Tropical Animal Health and Production - Flaviviruses (FVs) are arthropod-borne viruses of medical and veterinary importance. Numerous species of FVs have been isolated from various host; mainly...  相似文献   

First molecular detection of porcine bocavirus in Malaysia     

Daniel Mohan Jacob  Chee Yien Lee  Siti Suri Arshad  Gayathri Thevi Selvarajah  Faruku Bande  Bee Lee Ong  Peck Toung Ooi 《Tropical animal health and production》2018,50(4):733-739

Several strains of porcine bocaviruses have been reported worldwide since their first detection in Sweden in 2009. Subsequently, the virus has been reported to be associated with gastrointestinal and respiratory signs in weaner and grower pigs. Although Malaysia is host to a self-sufficient swine livestock industry, there is no study that describes porcine bocavirus in the country. This report is the first to describe porcine bocavirus (PBoV) in Malaysian swine herds. PBoV was identified in various tissues from sick and runt pigs using the conventional PCR method with primers targeting conserved regions encoding for the nonstructural protein (NS1) gene. Out of 103 samples tested from 17 pigs, 32 samples from 15 pigs were positive for porcine bocavirus. In addition, a higher detection rate was identified from mesenteric lymph nodes (52.9%), followed by tonsil (37.0%), and lungs (33.3%). Pairwise comparison and phylogenetic analyses based on a 658-bp fragment of NS1 gene revealed that the Malaysian PBoV strains are highly similar to PBoV3 isolated in Minnesota, USA. The presence of porcine bocavirus in Malaysia and their phylogenetic bond was marked for the first time by this study. Further studies will establish the molecular epidemiology of PBoV in Malaysia and clarify pathogenicity of the local isolates.  相似文献   

Regulation of flower development in Dendrobium crumenatum by changes in carbohydrate contents,water status and cell wall metabolism     

You-Min Yap  Chiang-Shiong LohBee-Lian Ong 《Scientia Horticulturae》2008

The involvement of carbohydrates, water potential, cell wall components and cell wall-based enzymes in regulating flower development in Dendrobium crumenatum was investigated. Plants were subjected to cold treatment to release floral buds from dormancy, and the various parameters were investigated from young floral bud stage till flower senescence. Development of floral buds was accompanied by progressive decrease in concentrations of fructans and starch. Upon full flower opening, concentration of soluble sugars was maximum, accompanied by a more negative water potential. High pectin methylesterase activity was observed during early bud development and decreased thereafter. Significant increase in activities of β-galactosidase, β-mannosidase and β-xylosidase was also observed during floral bud development. The cell walls of sepals and petals were modified extensively during floral bud and flower development, as observed by changes in the amounts of celluloses, hemicelluloses and total pectin. Pectin solubilisation was also observed to commence during early floral bud development. These results indicated that carbohydrate hydrolysis, osmotic changes and cell wall dissolution that began early in young floral buds, all regulated flower development in this sympodial orchid. Possible applications of the findings in the horticultural industry are discussed.  相似文献   

Quantification of historical livestock importation into New Zealand 1860–1979     

BM Binney  PJ Biggs  PE Carter  BM Holland  NP French 《New Zealand veterinary journal》2013,61(6):309-314

AIMS: To quantify the numbers of live cattle, sheep and poultry imported into New Zealand and, where possible, their country of origin from 1860 to 1979.

METHODS: Information on the origin and number of live animal importations into New Zealand was collected for cattle, sheep and poultry for the period 1868–1979 from the annual reports compiled by the New Zealand Registrar General's Office, Government Statistician's Office, Census and Statistics Office, Census and Statistics Department, Customs Department and Department of Statistics. Census data from 1851 to 1871 were also used to estimate the livestock population during this period. The number of animals imported and the mean population for each species in a decade were determined, and the major countries of origin were identified.

RESULTS: A large number of cattle (53,384) and sheep (604,525) were imported in the 1860s, and then there was a marked reduction in importations. Live poultry were imported in relatively small numbers (20,701) from 1880 to 1939, then 1,564,330 live poultry were imported between 1960 and 1979. Australia was the predominant country of origin for sheep between 1868 and 1959 (51,347/60,918; 84.3%) and of cattle between 1868 and 1979 (10,080/15,157; 66.5%). Only 6,712 (11.0%) sheep and 3,909 (25.8%) cattle were imported from the United Kingdom over the same periods, and even fewer from other countries.

CONCLUSIONS: The collated data and historical reports show that from 1860 to 1979 Australia has been the main source of livestock introduced into New Zealand. The pattern of importation showed that large numbers of cattle and sheep were initially imported in the 1860s, probably in response to rapid agricultural expansion. Thereafter importations continued at much reduced numbers. In contrast, relatively small numbers of poultry were introduced until the 1960s when large numbers were imported as part of the development of a modern high-production industry. The overall pattern for both cattle and sheep was of a bottleneck event, as initially a relatively limited number of animals arrived from outside populations, followed by population expansion with ongoing but limited immigration (admixture). Investigation into the genetic population structure of New Zealand's cattle and sheep, as well as their host-associated microorganisms, could reflect the impact of these early historical events.  相似文献   

A tree/crop interface design and its use for evaluating the potential of hedgerow intercropping     

M. R. Rao  M. M. Sharma  C. K. Ong 《Agroforestry Systems》1991,13(2):143-158

The paper describes a tree/crop interface (TCI) experiment designed to investigate the effects of row orientation using Leucaena leucocephala Lam. Each TCI plot consisted of a regularly pruned Leucaena hedge in the middle and 12 crop rows on either side. Eight such plots were arranged at 45° around a sole Leucaena plot with rows oriented in four compass directions viz., North-South, East-West, Northeast-Southwest and Northwest-Southeast.Results of four years from 1984 to 1987 did not show any effect of row orientation, and similarly, no effect was seen on crop rows due to their location on the windward or leeward side of the hedge. The TCI effect was positive on the first crop row in the first year because Leucaena grew slowly, but depressed the yield of the first 4 to 6 crop rows(1.8 to 2.7 m from hedge) in subsequent years. The negative effect of Leucaena was noted more on sunflower in a relatively dry year than on sorghum in other years.Results from the TCI plots were used to estimate the yield of five hedgerow intercropping (HI) systems with varying alley widths (2.7 to 9.9 m). Comparison with sole stands of Leucaena and crops indicated that HI was more productive particularly at close alley widths. For example, hedges spaced at 2.7 m and 3.6 m averaged 37% and 25% higher productivity than the respective sole stands; but this advantage may be an overestimation of the real potential.The relevance of TCI experiments for studying agroforestry systems, their merits and limitations, especially of the design employed in this study are discussed.  相似文献