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Jennifer Anne Davidson Rohan B. E. Kimber 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(1):99-110
Ascochyta blight causes significant yield loss in pulse crops worldwide. Integrated disease management is essential to take
advantage of cultivars with partial resistance to this disease. The most effective practices, established by decades of research,
use a combination of disease-free seed, destruction or avoidance of inoculum sources, manipulation of sowing dates, seed and
foliar fungicides, and cultivars with improved resistance. An understanding of the pathosystems and the inter-relationship
between host, pathogen and the environment is essential to be able to make correct decisions for disease control without compromising
the agronomic or economic ideal. For individual pathosystems, some components of the integrated management principles may
need to be given greater consideration than others. For instance, destruction of infested residue may be incompatible with
no or minimum tillage practices, or rotation intervals may need to be extended in environments that slow the speed of residue
decomposition. For ascochyta-susceptible chickpeas the use of disease-free seed, or seed treatments, is crucial as seed-borne
infection is highly effective as primary inoculum and epidemics develop rapidly from foci in favourable conditions. Implemented
fungicide strategies differ according to cultivar resistance and the control efficacy of fungicides, and the effectiveness
of genetic resistance varies according to seasonal conditions. Studies are being undertaken to develop advanced decision support
tools to assist growers in making more informed decisions regarding fungicide and agronomic practices for disease control. 相似文献
2.
Virus Location and Lymphocyte Apoptosis in Lymph Nodes of Piglets Infected with PCV-2 总被引：1，自引：0，他引：1
SHI Lü-juan 《中国农业科学(英文版)》2008,7(4):507-512
The present study has been performed to understand the location of the virus, type of apoptotic cells, and their relation to lymph nodes of piglets infected with porcine circovirus type Ⅱ （PCV-2）. Nine 32-day-old conventional piglets free of infection with PCV-2 were used, and distributed into three groups： control group （n = 3）, piglets inoculated with PCV-2 alone （PCV-2, n = 3）, and PCV-2 inoculated and KLH immunostimulated group （PCV-2 ＋ KLH, n = 3）. Superficial inguinal lymph nodes from all piglets were collected for histological examination after 32 days postinoculation, and immunohistochemistry for PCV-2 detection. Location of apoptotic cells was detected with TdT-mediated dUTP nick end labeling （TUNEL） and cell cycle, and the apoptotic rates were measured by flow cytometry. The characteristic histopathological lesions of the piglets in PCV-2 and PCV-2 ＋ KLH were lymphocyte depletions in the cortex and paracortex of the lymph nodes, epithelioid-like macrophage infiltration, and intracytoplasmic inclusion bodies presented in epithelioid-like macrophages. PCV-2 was mainly found in epithelioid-like macrophages by immunohistochemistry. In the lymph nodes, lymphocytes presented higher apoptotic rates in the cortex by TUNEL, special B-cell areas, and similar apoptotic cells were found in this compartment in the control. The apoptotic rates of the lymph nodes were 0.41, 3.34, and 4.88% in the control, PCV-2, and PCV-2 ＋ KLH groups by flow cytometry, respectively. The apoptotic rates of lymph nodes for PCV-2 and PCV-2 ＋ KLH piglets were significantly higher than those for the control group （P〈0.05 and P〈0.01）. The proliferation index （PI） was 0.17_＋0.01, 0.12_＋0.01 and 0.12_＋0.04 in the control, PCV-2, and PCV-2 ＋ KLH group, the PI of the control group was higher than that of the other groups, but without the statistical difference. PCV-2 can induce lymphocyte depletion in lymph nodes of piglets by blocking cell proliferation and promoting apoptosis. This is one o 相似文献
3.
Aspergillus section Flavi is able to produce aflatoxins (AFs) in vitro down to 0.85 aw with a potential maximum occurring between 0.95 and 0.99 aw, while in the field AFs increased significantly with kernel humidity below 0.95 aw. In order to clarify this apparent discrepancy, a 3-year field trial with artificial inoculation of maize ears with Aspergillus flavus strains was organised. The co-occurrence of Aspergillus section Flavi and Gibberella fujikuroi species complex (Gfsc) was observed. The incidence of A. flavus was significantly influenced by the year and negatively related to Gfsc incidence. In 2012, when the highest temperature and the lowest rain were registered, aflatoxin B1 (AFB1) content was the highest and aw < 0.95 in kernels was measured early throughout the growing season. In 2013 and 2014, the temperature was lower and rain more abundant, and aw decreased below 0.95 only close to harvest and AFB1 contamination was limited. The possibility of describing/predicting reasonably well aw dynamic based on temperature, (degree day) was confirmed. With aw > 0.95, a positive correlation between AFB1 production rate and aw was found, but a negative correlation resulted with aw < 0.95. Other factors than aw play a role, but aw = 0.95 should be considered as an indicator of suitable conditions for rapid aflatoxin accumulation. 相似文献
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对1996年鉴定的30份感病品种(品系)含88个单株后代,以成株率为依据,测定一次性自然选择效果,用模糊数学的隶属函数值U(X)进行综合评判。表明同一材料株间感病性存在差异,群体抗病性趋与减弱。从感病的群体中可以选到抗病的单株后代。 相似文献
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为了探讨高尔基体与细菌增殖和周膜扩展的关系,用电子显微镜研究了大豆根瘤侵染细胞发育中高尔基体的变化.结果表明:幼龄侵染细胞中有高尔基体,但在成熟和衰老的侵染细胞中却几乎没有这种结构.高尔基体随幼龄侵染细胞中细菌的增多而增多,它们主要位于细菌附近.这些高尔基体的生理活性较高,不断向周围的细胞质分泌含有纤维状物质的小泡,有的小泡还在向细菌运动.一些小泡位于细菌的周膜上,其附近细菌的周膜常向外形成隆起,并有纤维状物质出现在其中.由此说明,大豆根瘤侵染细胞中的高尔基体参与了细菌的增殖和周膜的扩展. 相似文献
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为探索干热处理后带菌种子贮藏时间对种子发芽率及病菌活力的影响,明确干热处理后种子贮藏的最佳条件。以3种自然带菌的黄瓜种子为材料,将不同干热处理后的带菌黄瓜种子在4℃中分别贮藏1,2,3,6,9个月,测定贮藏时间对种子发芽率的影响,同时采用平板保湿培养法和荧光双染技术测定种子上病原真菌活力的变化。结果表明,干热处理带菌黄瓜种子的发芽率和种子上病原菌的活力随贮藏时间的延长呈现下降趋势。70℃处理40,60 min的黄瓜种子贮藏3个月后,3种带菌种子的发芽率均保持在88％以上,贮藏6个月后,发芽率均下降至约80％,70℃处理90 min的黄瓜种子贮藏3个月后,3种带菌种子的发芽率均下降至75％以下;而贮藏3个月后,带菌种子内外均无病原菌生长,孢子死亡率均上升至100％。说明70℃干热处理40,60 min后的带菌黄瓜种子贮藏3个月后发芽率仍在88％以上且病原菌死亡率达100％,因此,可作为种子贮藏前的处理条件,但70℃干热处理90 min后的种子适宜直接播种,且干热处理后的种子不适宜长期贮藏。 相似文献
8.
豌豆根瘤侵染细胞发育中造粉体的研究 总被引：1，自引：0，他引：1
透射电镜研究表明,在豌豆根瘤侵染细胞发育过程中,造粉体的形态结构处在变化之中.在发育早期,造粉体较多,分布在细胞壁附近.它的基质很少,多含有呈长梭形的、电子密度非常低的淀粉粒,并有一些电子密度较高的条带结构.随着细胞的发育,造粉体逐渐移至胞间隙周围,不断变小,切面近似椭圆形或圆形.进一步发育时,造粉体中的淀粉粒越 相似文献
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