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141.
家禽产业的发展离不开生物安全措施的保障,其中对疫情的监测十分重要,不仅影响家禽的生产性能,而且关系到产业的健康发展。作者以禽流感的监测为例,为家禽疫病的监测提供了良好的指导和借鉴。 相似文献
142.
2007年9月30日至10月3日,笔者随警作战,记录下上海市轨道公安分局警犬大队29名民警参加国庆安保工作的过程。整理这段笔记时,阵阵发自内心深处的震撼在灵魂深处激荡。这是一次在挑战面前的完美"亮剑",在关键时刻的刚毅"突击"。 相似文献
143.
蜜蜂是设施农业的重要授粉昆虫,授粉蜂群的状况可能影响授粉效率的高低。通过意大利蜂(Apismellifera)对温室草莓、油桃的6次授粉重复试验,采集授粉蜂群的蜂子比值与出勤率的数据,分析蜂子比值与出勤率的相关性。结果表明,蜂子比值与工蜂出勤率之间呈显著的负相关(P<0.05),其相关系数分别为-0.8470、-0.6543、-0.7616、-0.6969、-0.6740和-0.8477,说明在正常范围内,温室授粉蜂群的出勤率随蜂子比值的减小而提高,也就是说,授粉蜂群内的子脾越好,蜜蜂出勤采集的积极性越高。 相似文献
144.
Biological Control of Sclerotinia Diseases of Rapeseed by Aerial Applications of the Mycoparasite Coniothyrium minitans 总被引:1,自引:0,他引:1
G. Q. Li H. C. Huang H. J. Miao R. S. Erickson D. H. Jiang Y. N. Xiao 《European journal of plant pathology / European Foundation for Plant Pathology》2006,114(4):345-355
Indoor and field experiments were conducted to evaluate the efficacy of applying the mycoparasite Coniothyrium minitans to the aerial parts of rapeseed plants at the flowering stage to control sclerotinia diseases caused by Sclerotinia sclerotiorum. Under controlled conditions, a petal inoculation technique was used to determine the effect of conidial suspensions of C. minitans on suppression of sclerotinia leaf blight. Results showed that C. minitans was effective in inhibiting infection initiated by ascospores of S. sclerotiorum on flower petals by restricting mycelial growth of the pathogen. Suppression of lesion development was related to the conidial
concentration of C. minitans, with larger lesions at low concentration (5×103conidia ml−1), but smaller lesions at high concentration (5×104 conidia ml−1 or higher). When C. minitans-treated rapeseed leaves were inoculated with mycelia of S. sclerotiorum, C. minitans failed to prevent infection of leaves, but caused a significant reduction in number of sclerotia produced on the diseased
leaves. No significant difference in efficacy was detected between the two isolates of C. minitans, LRC 2137 and Chy-1, on the two rapeseed cultivars, Westar (spring type) and Zhongyou 821 (winter type). Results of field
trials showed a significant reduction of stem rot of rapeseed in four (1997, 1999, 2003 and 2004) out of five years by aerial
application of C. minitans, compared with controls. No significant difference in suppressive efficacy was observed between the treatments of C. minitans (106 conidia ml−1), C. minitans (106 conidia ml−1) + benomyl (50 μg ml−1) and benomyl (100 μg ml−1) in 2003, and between the treatments of C. minitans (106 conidia ml−1), C. minitans (106 conidia ml−1) + vinclozolin (100 μg ml−1) and vinclozolin (500 μg ml−1) in 2004. Sclerotia of S. sclerotiorum collected from diseased plants in plots treated with C. minitans in 1999, 2000 and 2003, or with C. minitans + benomyl in 2003 were infected by C. minitans at frequencies ranging from 21.3 to 54.5%. This study concludes that aerial spraying of C. minitans is an effective method for controlling sclerotinia diseases of rapeseed. 相似文献
145.
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147.
Inter-simple sequence repeat (ISSR) markers were used to evaluate interspecific relationships of Lycoris. Twenty-four samples were included in the study representing a total of 20 among species and varieties. Thirteen primers produced 228 discernible DNA fragments, 205, or 89.91%, of which were polymorphic, indicating a high level of interspecific genetic variation in Lycoris. Our UPGMA cluster analysis recognized four major groups of species, which were consistent with morphological and karyotype observations. The first group included species with telocentric and metacentric chromosomes, while the second consisted of species with a haploid genome of 11 subtelocentric chromosomes. The third group contained species with a mixture of subtelocentric, telocentric and metacentric chromosomes. The last group included the Japanese and Korean species. Lycoris anhuiensis was clustered within accessions of Lycoris longituba, suggesting that it could be recognized as a variety of L. longituba. Our ISSR data also suggested that L. straminea may be a hybrid between Lycoris chinensis and Lycoris radiata var. pumila, and that L. caldwellii, an allotriploid, may be of a hybrid origin of L. chinensis and L. sprengeri. 相似文献
148.
Gas exchange and chlorophyll fluorescence quenching analysis were carried out to investigate the diurnal variations in photosynthesis and light allocation in leaves of soybean. Leaf net CO2 assimilation rate showed a bimodal diurnal pattern and midday depression of CO2 assimilation was observed at 13:00 h. Depression in CO2 assimilation at midday was mostly attributed to non-stomatal limitation since the reduction in net CO2 assimilation rate was not followed by significant reductions in stomatal conductance and intracellular CO2 concentration. Midday depression in CO2 assimilation was found to be associated with reversible inactivation of photosystem II reaction centers and increases of antenna heat dissipation and photorespiration in response to the high light intensity. It is likely that PS II down-regulation, heat dissipation and photorespiration co-operated together to prevent the chloroplast from photodamage. 相似文献
149.
150.
添加有机硅表面活性剂对低容量喷雾防治小麦蚜虫的影响 总被引:11,自引:2,他引:11
室内试验表明,有机硅表面活性剂Silwet408、非离子表面活性剂OP-10和JFC可显著降低药液的表面张力,其中Silwet408在质量分数为0.05%时可使水的表面张力降到22.05 mN/m,表面活性最强。当药液中含有0.001%的有机硅表面活性剂Silwet408时,其在小麦叶片上的接触角即开始显著减小,且在小麦背面的接触角小于在正面的接触角。在10%吡虫啉可湿性粉剂稀释2500倍药液中添加Silwet408,药液的表面张力和其在小麦叶片上的接触角明显降低,雾滴在小麦叶片上扩展面积明显增大。进一步田间试验表明,使用手持离心式低容量喷雾机喷雾,在10%吡虫啉可湿性粉剂药液中添加质量分数为0.05%和0.1%的Silwet408,可显著增加对小麦蚜虫的防治效果。 相似文献