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991.
小麦印度腥黑穗病菌在中国适生性的初步研究   总被引:9,自引:2,他引:9  
白章红  周国梁 《植物检疫》1997,11(6):331-334
本文依据小麦印度腥黑穗病菌的生物学特性,及世界各主要小麦产区的地理气候资料,利用地理信息系统对该病菌的适生性进行了研究。结果表明,小麦印度腥黑穗病菌适生气候条件为:大于零度以上的有效积温≥1300日度;1年中最冷月的平均温度≤20℃;小麦抽穗扬花期间的平均温度为7℃~29℃,平均大气相对湿度≥48%。  相似文献   
992.
Epidemiological investigations into the pancreas disease (PD) of farmed salmon were conducted on populations of Atlantic salmon reared in Ireland during 2003 and 2004. The investigations surveyed all marine salmon farms operating in Ireland through a detailed questionnaire with follow-up farm visits. Information was gathered on 21 populations of fish in 2003 and 14 populations in 2004. Thirteen of the 21 populations suffered PD in 2003 and 12 of the 14 in 2004. The mean mortality due to PD on affected farms was 18.8% in 2003 and 14.8% in 2004 and the loss of growth due to PD was estimated at 11.4% over the 2-year period. The highest risk periods for outbreaks of PD were early summer and early autumn and the farms most seriously affected by PD mortality were in the western counties of Ireland. Factors which showed an indication of association with a PD outbreak or high mortality during a PD outbreak were: livestock movement to another sea site, high feeding rate prior to any PD outbreak, the presence of another PD positive farm in the same water body, greater than 250000 fish on a site, a previous history of PD on a site, a high sea lice burden, and sites located in the western regions of Ireland which reared a specific strain of salmon.  相似文献   
993.
水分胁迫下华山松抗腐烂病的研究   总被引:1,自引:0,他引:1  
用不同浓度的聚乙二醇(PEG6000)对华山松幼苗进行诱导水分胁迫,树皮的相对膨胀度(RT值)随PEG浓度的增大而下降;且树皮内的酚类物质含量、多酚氧酶(PPO)活性和苯丙氨酸解氨酶(PAL)活性均有所降低,过氧化物酶(POD)活性升高。说明水分状况直接影响着华山松的抗病性。4种酚类物质抑菌试验表明,一定浓度下酚类物质对腐烂病病原菌松黑腐皮壳(Valsa pirni Fr.)菌丝体生长有抑制作用,以香草醛和邻苯二酚抑菌能力最强。  相似文献   
994.
为了分析南疆喀什市温室蔬菜病虫害种类及发生情况,2017年在喀什市进行了温室蔬菜病虫害调查,共调查了21种蔬菜,其中在16种蔬菜上共发现了12种病害,在15种蔬菜上共发现了4种虫害。综合来看,为害南疆喀什市温室蔬菜的主要病害种类为煤污病、腐烂病、白粉病以及病毒病,主要虫害种类为斑潜蝇、白粉虱和菜蛾。结合当地生产实际情况,分析了温室蔬菜病虫害的发生特点和发生原因,初步构建了喀什市温室蔬菜病虫害综合防治技术体系。  相似文献   
995.
The Mount Lofty Ranges koala (Phascolarctos cinereus) population in South Australia has a high prevalence of the renal disease oxalate nephrosis, for which an underlying genetic cause is suspected. South Australian koalas primarily originate from those in French Island, Victoria; however, oxalate nephrosis has not previously been reported in Victorian koalas. Examination of kidney tissue sections from 63 koalas across Victoria found that nine koalas were affected by oxalate nephrosis (14.3%). These included 2/5 koalas from French Island (40%), 4/14 koalas from the western regions (29%), 2/11 Raymond Island koalas (18%), and 1/13 Cape Otway koalas (8%). There were no cases of oxalate nephrosis identified in the Strzelecki koalas (n = 12). These findings suggest that oxalate nephrosis occurs in koalas from French Island and populations that have received significant influx of koalas from French Island, but not in the Strzelecki region, which has little to no French Island input. This lends support to the theory that an inherited abnormality of oxalate metabolism could underlie the high prevalence of oxalate nephrosis in the Mount Lofty Ranges koala population, and molecular investigations are currently underway to investigate a genetic cause.  相似文献   
996.
疫病一直是生猪养殖中影响猪群健康的重要因素,受到疾病影响的猪群会给养殖户带来巨大的经济损失,严重阻碍养殖业的发展。该文将简要概述猪丹毒和猪肺疫的病理状况,分析猪丹毒和猪肺疫混合感染的发病特征和临床症状,并研究综合诊治猪丹毒和猪肺疫混合感染的方法,降低猪丹毒和猪肺疫混合感染对生猪养殖的影响。  相似文献   
997.
998.
Phycobiliproteins (PBPs) are proteins of cyanobacteria and some algae such as rhodophytes. They have antimicrobial, antiviral, antitumor, antioxidative, and anti-inflammatory activity at the human level, but there is a lack of knowledge on their antifungal activity against plant pathogens. We studied the activity of PBPs extracted from Arthrospira platensis and Hydropuntia cornea against Botrytis cinerea, one of the most important worldwide plant-pathogenic fungi. PBPs were characterized by using FT-IR and FT-Raman in order to investigate their structures. Their spectra differed in the relative composition in the amide bands, which were particularly strong in A. platensis. PBP activity was tested on tomato fruits against gray mold disease, fungal growth, and spore germination at different concentrations (0.3, 0.6, 1.2, 2.4, and 4.8 mg/mL). Both PBPs reduced fruit gray mold disease. A linear dose–response relationship was observed for both PBPs against disease incidence and H. cornea against disease severity. Pathogen mycelial growth and spore germination were reduced significantly by both PBPs. In conclusion, PBPs have the potential for being also considered as natural compounds for the control of fungal plant pathogens in sustainable agriculture.  相似文献   
999.
天目山不同海拔高度柳杉瘿瘤病对柳杉健康的影响   总被引:3,自引:1,他引:3  
柳杉Cryptomeria fortunei是浙江天目山国家级自然保护区主要的景观树种。目前,瘿瘤病成为引起柳杉衰退一种非常严重的病害。在调查了天目山不同海拔高度柳杉瘿瘤病害的基础上,测定了对照柳杉和有瘤柳杉的各项生理生态指标。结果显示,随着海拔的升高,天目山柳杉的树龄逐渐增大,瘿瘤病对柳杉相对叶绿素含量(SPAD值)和叶片相对含水率的影响度逐渐增大,对光合参数以及蒸腾速率的影响则呈减小的趋势;随着海拔的升高,对照柳杉的各项生理参数逐渐减小。这在一定程度上说明了柳杉自身的老龄化也是影响天目山柳杉健康进而导致种群衰退的一个重要原因。图2表3参18  相似文献   
1000.
A healthy soil is often defined as a stable soil system with high levels of biological diversity and activity, internal nutrient cycling, and resilience to disturbance. This implies that microbial fluctuations after a disturbance would dampen more quickly in a healthy than in a chronically damaged and biologically impoverished soil. Soil could be disturbed by various processes, for example addition of a nutrient source, tillage, or drying-rewetting. As a result of any disturbance, the numbers of heterotrophic bacteria and of individual species start to oscillate, both in time and space. The oscillations appear as moving waves along the path of a moving nutrient source such as a root tip. The phase and period for different trophic groups and species of bacteria may be shifted indicating that succession occurs. DGGE, Biolog and FAME analysis of subsequent populations in oscillation have confirmed that there is a cyclic succession in microbial communities. Microbial diversity oscillates in opposite direction from oscillations in microbial populations. In a healthy soil, the amplitudes of these oscillations will be small, but the background levels of microbial diversity and activity are high, so that soil-borne diseases will face more competitors and antagonists. However, soil-borne pathogens and antagonists alike will fluctuate in time and space as a result of growing plant roots and other disturbances, and the periods and phases of the oscillations may vary. As a consequence, biological control by members of a single trophic group or species may never be complete, as pathogens will encounter varying populations of the biocontrol agent on the root surface. A mixture of different trophic groups may provide more complete biological control because peaks of different trophic groups occur at subsequent locations along a root. Alternatively, regular addition of soil organic matter may increase background levels of microbial activity, increase nutrient cycling, lower the concentrations of easily available nutrient sources, increase microbial diversity, and enhance natural disease suppression.  相似文献   
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