油茶炭疽病的研究   总被引：9，自引：0，他引：9  

袁嗣令  张能唐  翁月霞  花锁龙  刘惠珍  蒙美琼 《植物保护学报》1963,2(3):253-262

油茶炭疽病引起落花、落蕾、落果及落叶。病落果率约为全年总落果率的60%,根据标准株平均统计,病落蕾率占总落蕾率的26—45%。通过菌种形态比较与接种试验,肯定病原与茶叶上云纹叶枯病菌系同一种为 Colletotrichum camelliae Massee。其无性世代发生在寄主各部位,呈现不同征状,有性世代仅出现在连续阴雨一个月以上的枝梢及花蕾的病斑上。分生孢子具有抗旱及抗低温能力,但不能忍受冰冻温度。初次侵染来源为枝干的溃疡斑及病蕾蕾痕,经春雨浸湿大量产生,通过雨中风力广泛传布。干燥气流在传病上不起作用。夏、秋晨间露水滴溅也可使病菌孢子扩散侵染。根据湘西怀化县长期观察试验,象鼻虫在传病上并不是重要因素。各地区温差影响发病迟早,湿差影响严重度,雨天日数决定落蕾、落果的数量与时期。品种抗病性差异除形态特征外(气孔数量、角质层厚薄等),可能与表皮细胞层次与缀密度以及细胞的内含成份有关,果形及色泽与抗病性差异无实质关系。小果型品种(湖南珍珠于、苦槠子,江西宜春中子)的抗病性可能由上述的特性决定。  相似文献   

CLINICAL,DIAGNOSTIC, AND PATHOLOGICAL FEATURES OF 2 CASES OF METASTATIC IRIDOPHOROMA IN A VEILED CHAMELEON (CHAMAELEO CALYPTRATUS) AND A RED-BARRED DRAGON (CTENOPHORUS VADNAPPA)     

Lydia J. Tong  Whitney Ong  Frances Hulst  Gabrielle Tobias  Kimberly Vinette Herrin  Larry Vogelnest 《Journal of Exotic Pet Medicine》2018,27(4):53-60

Iridophores are iridescent cutaneous pigment cells found in reptiles, fish, and amphibians. Neoplasms of iridophores are rarely reported, and little is known about their behaviour, metastatic potential, and prognostic indicators. This paper reports details of the clinical course and pathological findings of metastatic iridophoroma in a veiled chameleon (Chamaeleo calyptratus) and red-barred dragon (Ctenophorus vadnappa). The veiled chameleon presented with a subcutaneous mass on the right lateral elbow and was diagnosed as an iridophoroma on fine needle aspiration. It was otherwise clinically normal. Within 35 days of excision, multiple secondary skin masses developed which were often non-pigmented and required microscopic examination to identify them as iridophoroma metastases. There were in total 54 days between the first detection of the primary mass and end stage, extensive cutaneous and visceral metastatic disease, and there had been no detectable primary mass during routine clinical examination 128 days prior to death. The red-barred dragon presented with a white sub-mandibular mass. While undergoing an excisional biopsy the animal expired, post-mortem examination revealed a cutaneous malignant iridophoroma with tumour cell clusters seen in pulmonary arterial vessels, suggesting that surgical handling of iridophoroma could precipitate the release of circulating tumour cell clusters. This is the first iridophoroma described in a red-barred dragon and the second report of a malignant iridophoroma in a veiled chameleon. Timely detection and careful excision of lizard iridophoroma may be an important factor in clinical outcome.  相似文献   

Solar Photocatalytic Mineralization of Dye New Coccine in Aqueous Phase Using Different Photocatalysts     

Wan Fadhilah Khalik  Li-Ngee Ho  Soon-An Ong  Yee-Sian Wong  Nik Athirah Yusoff  Fahmi Ridwan 《Water, air, and soil pollution》2016,227(4):118

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Inhibitory Effects of Copper on Nitrifying Bacteria in Suspended and Attached Growth Reactors     

Yong-Woo Lee  Qing Tian  Say Kee Ong  Chikashi Sato  Jinwook Chung 《Water, air, and soil pollution》2009,203(1-4):17-27

Municipal wastewaters with industrial discharges typically contain heavy metals which may inhibit the biological processes in wastewater treatment plants. In this study, copper inhibition on strict nitrifiers in a suspended growth (SG) reactor and a combined attached and suspended growth (A&SG) reactor was compared. Both reactors were subjected to a continuous copper input of 5 mg/L. When the accumulated total copper concentration in the reactor were approximately 25 mg/L (due to sorption to the biomass), a sharp decrease in nitrification (increase in inhibition) were observed in the SG reactor while nitrification remained the same for the A&SG reactor indicating that attached growth systems were more robust against copper toxicity than suspended growth systems. Using MINTEQA2, the concentrations of various chemical species were estimated and, of the different species present, adsorbed copper in the biomass and aqueous Cu(NH₃)₄ ⁺² were found to positively correlate with percent inhibition of nitrification. Based on the changes in the concentrations of the two species, Cu(NH₃)₄ ⁺² was probably the main chemical species responsible for inhibition of nitrification. This study has implications for wastewater treatment plants treating wastewaters with high ammonia and copper present.  相似文献   

Understorey microclimate and crop performance in a Grevillea robusta-based agroforestry system in semi-arid Kenya     

J.E. Lott  C.K. Ong  C.R. Black 《Agricultural and Forest Meteorology》2009,149(6-7):1140-1151

The influence of dispersed trees on microclimatic conditions, gas exchange and productivity of maize (Zea mays L.) in a Grevillea robusta-based agroforestry system in semi-arid Kenya was examined to test the hypothesis that the benefits of shade seen in savannah ecosystems may be outweighed by competition for below-ground resources. Meristem temperature, cumulative thermal time, intercepted radiation, spatial distribution of shade and gas exchange were determined for maize grown as sole crops, in an agroforestry system, or under shade nets providing 25 or 50% reductions in incident radiation to discriminate between effects of shade and below-ground competition. The major benefit of shade was to reduce exposure to the supra-optimal temperatures experienced in many tropical regions, and which are predicted to become increasingly common by climate change models. However, although trees decreased photosynthetic photon flux density (PPFD) incident on understorey maize by ca. 30%, the yield reduction was much greater than in the 25% shade net treatment in four seasons providing contrasting rainfall. Maize yield was unaffected by 50% artificial shade in the driest season (168 mm) but decreased with increasing shade when rainfall was high (628 mm). Shade reduced meristem temperature and delayed flowering by 5–24 days depending on treatment and seasonal rainfall. Thermal time to flowering in the agroforestry system doubled from 600 to 1200 °C day as rainfall decreased. Photosynthetic and transpiration rates for understorey maize were similar to the 25 and 50% shade treatments when rainfall was high, but were ca. 10% of those for unshaded sole maize in dry seasons. PPFD-saturated photosynthetic rate was initially similar in all treatments but fell sharply in the agroforestry system as the season progressed. Radiation conversion coefficients did not differ between unshaded sole and understorey maize. The results suggest that the ameliorative influence of tree shade was greater in low rainfall seasons, as in savannah systems, but that potential benefits were outweighed by below-ground competition. This may be managed by root-pruning trees.  相似文献   

Gas exchange responses of <Emphasis Type="Italic">Eucalyptus</Emphasis>, <Emphasis Type="Italic">C. africana</Emphasis> and <Emphasis Type="Italic">G. robusta</Emphasis> to varying soil moisture content in semi-arid (Thika) Kenya     

Kuyah Shem  Muthuri Catherine  Chin Ong 《Agroforestry Systems》2009,75(3):239-249

A dramatic decline in forest cover in eastern Africa along with a growing population means that timber and poles for building and fuelwood are in short supply. To overcome this shortage, the region is increasingly turning to eucalyptus. But eucalyptus raises environmental concerns of its own. Fears that it will deplete water supply, affect wildlife and reduce associated crop yields have caused many countries in the region to discourage farmers from planting this exotic. This paper is part of a series of investigations on the growth and water use efficiency of faster growing eucalyptus hybrids, which was introduced from South Africa to Kenya. The hypothesis is that the new hybrids are more efficient in using water and more suitable for the semi-arid tropics than existing eucalyptus and two popular agroforestry species. Gas exchange characteristics of juvenile Eucalyptus grandis (W. Hill ex Maiden), two eucalyptus hybrids (E. grandis × Eucalyptus camaldulensis Dehnh.), Grevillea robusta (A. Cunn) and Cordia africana (Lam) was studied under field and pot conditions using an infrared gas analyzer was used to measure photosynthetic active radiation (PAR), net photosynthetic rate (A), stomatal conductance (g _s) and transpiration rate (E) at CO₂ concentrations of 360 μmol mol⁻¹ and ambient humidity and temperature. A, E and g _s varied between species, being highest in eucalyptus hybrid GC 15 (24.6 μmol m⁻² s⁻¹) compared to eucalyptus hybrid GC 584 (21.0 μmol m⁻² s⁻¹), E. grandis (19.2 μmol m⁻² s⁻¹), C. africana (17.7 μmol m⁻² s⁻¹) and G. robusta (11.1 μmol m⁻² s⁻¹). C. africana exhibited high E values (7.0 mmol m⁻² s⁻¹) at optimal soil moisture contents than G. robusta (3.9 mmol m⁻² s⁻¹) and eucalyptus (5.3 mmol m⁻² s⁻¹) in field experiment and G. robusta (3.2 mmol m⁻² s⁻¹) and eucalyptus (4.2 mmol m⁻² s⁻¹) in pot-grown trees. At very low soil moisture content, extremely small g _s values were recorded in GC 15 and E. grandis (8 mmol m⁻² s⁻¹) and G. robusta (14 mmol m⁻² s⁻¹) compared to GC 584 (46.9 mmol m⁻² s⁻¹) and C. africana (90.0 mmol m⁻² s⁻¹) indicating strong stomatal control by the species. Instantaneous water use efficiency ranged between 3 and 5 μmol mmol⁻¹ and generally decreased with decline in soil moisture in pot-grown trees but increased with declining soil moisture in field-grown trees.  相似文献   

Relationships of High Molecular Weight Glutenin Subunit Composition and Molecular Weight Distribution of Wheat Flour Protein with Water Absorption and Color Characteristics of Noodle Dough     

J.‐B. Ohm  A. S. Ross  C. J. Peterson  Y.‐L. Ong 《Cereal Chemistry》2008,85(2):123-131

Colors of noodle doughs made from hard white winter wheat flours from Oregon were measured at optimum noodle water absorptions (NWA). Partial correlations, removing effect of protein concentration, indicated that NWA had negative relationships with 0 hr L* and 24 hr b*, and positive relationships with 0 and 24 hr a*. Kernel hardness index had positive simple and partial correlations with NWA without any significant (P < 0.05) correlation with color parameters. High molecular weight glutentin subunits (HMW‐GS) significantly (P < 0.05) affected all measured noodle parameters except for 0 hr L*. Covariance analysis, using protein concentration as a covariate, indicated that HMW‐GS significantly affected NWA and a* (P < 0.01). Wheat cultivars with HMW‐GS 17+18 showed significantly higher mean NWA and a* values than those with alternative Glu‐B1 subunits. Protein molecular weight distributions affected noodles, as shown by significant correlations with absorbance areas and % areas of protein size exclusion (SE) HPLC chromatograms. Protein fractions that had positive correlations with redness had negative correlations with yellowness. Applying multivariate analyses to SE‐HPLC data to derive calibration models to predict fresh noodle dough a* and b* values had R² > 0.91 and cross validations values of R² > 0.75.  相似文献   

Retrospective evaluation of cats with elapid snake envenomation associated neurotoxicity requiring mechanical ventilation: 12 cases (2005–2014)          下载免费PDF全文

Hui Mei Ong BVSc  MANZCVS  Kylie Kelers BSc  BVMS  FANZCVS  Dez Hughes BVSc  MRCVS  DACVECC  Manuel Boller Dr med vet  MTR  DACVECC 《Journal of Veterinary Emergency and Critical Care》2017,27(5):579-585

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Characterization of the first two viruses described from wild populations of hammer orchids (Drakaea spp.) in Australia          下载免费PDF全文

J. W. L. Ong  R. D. Phillips  K. W. Dixon  M. G. K. Jones  S. J. Wylie 《Plant pathology》2016,65(1):163-172

Sequences representing the genomes of two distinct virus isolates infecting wild plants of two members of the genus Drakaea (hammer orchids) in Western Australia are described. The virus isolated from Drakaea livida has a bipartite genome of 4490 nt (RNA1) and 2905 nt (RNA2) that shares closest sequence and structural similarity to members of the genus Pecluvirus, family Virgaviridae, described from legumes in the Indian subcontinent and West Africa. However, it differs from pecluviruses by lacking a P39 protein on RNA2 and having a cysteine‐rich protein gene located 3′ of the triple gene block protein genes. It is the first peclu‐like virus to be described from Australia. The name Drakaea virus A is proposed (DVA; proposed member of the family Virgaviridae, genus unassigned). The second virus isolate was identified from Drakaea elastica, a species classed as endangered under conservation legislation. The genome sequence of this virus shares closest identity with isolates of Donkey orchid symptomless virus (DOSV; proposed member of the order Tymovirales, family and genus unassigned), a species described previously from wild Caladenia and Diuris orchids in the same region. These viruses are the first to be isolated from wild Drakaea populations and are proposed to have an ancient association with their orchid hosts.  相似文献   

Comparative Study on Photocatalytic Degradation of Mono Azo Dye Acid Orange 7 and Methyl Orange under Solar Light Irradiation   总被引：2，自引：0，他引：2  

Soon-An Ong  Ohm-Mar Min  Li-Ngee Ho  Yee-Shian Wong 《Water, air, and soil pollution》2012,223(8):5483-5493

The objective of this study was to investigate and compare the kinetic photocatalytic degradation of mono azo dyes Acid Orange 7 (AO7) and Methyl Orange (MO) under solar light irradiation with titanium dioxide (TiO₂) as a photocatalyst. Several operational parameters affecting the photocatalytic degradation of dye were evaluated such as different azo dyes, initial dye concentration, TiO₂ dosage, with and without aeration and sunlight irradiation. The data obtained was well fitted with the Langmuir?CHinshelwood kinetic model. It was observed that the pseudo-first-order rate constants for AO7 were higher than MO in all cases, indicating that the photocatalytic degradation of AO7 was easier and more rapid than MO. The analysis of chemical oxygen demand and UV?CVis spectra shows the AO7 and MO not only being decolorized due to the breakdown of azo bond but also being mineralized if the azo dye solutions were continually exposed to solar light irradiation after the decolorization process.  相似文献