Germinate to exterminate: chemical stimulation of Spongospora subterranea resting spore germination and its potential to diminish soil inoculum          下载免费PDF全文

M. A. Balendres  T. J. Clark  R. S. Tegg  C. R. Wilson 《Plant pathology》2018,67(4):902-908

Hoagland's solution (HS), a defined nutrient supplement for plants, has been previously reported to stimulate zoospore release from resting spores of the potato pathogen Spongospora subterranea f. sp. subterranea. This study obtained direct empirical evidence for an increase in zoospore release with HS treatment, and identified Fe‐EDTA as the stimulant component of HS. Stimulation of resting spores by HS and Fe‐EDTA resulted in greater and earlier zoospore release compared to a distilled water control, and in the presence of a susceptible tomato host plant resulted in enhanced root infection. Given the labile nature of S. subterranea zoospores, it was postulated that stimulation of premature release of zoospores from the dormant resting spores in absence of susceptible hosts could reduce soil inoculum levels. In two glasshouse trials in the absence of host plants, both Fe‐EDTA and HS soil treatments reduced S. subterranea soil inoculum levels, providing proof of concept for the ‘germinate to exterminate’ approach to inoculum management.  相似文献   

初始pH对嗜线虫致病杆菌YL001菌株抑菌活性及代谢的影响     

郭树奇  许鹏  鲁梅 《西北农林科技大学学报(自然科学版)》2016,44(6):132-140

【目的】研究初始培养pH对Xenorhabdus neamatophila YL001发酵液抑菌活性的影响,为进一步提高YL001的抑菌活性提供理论依据。【方法】采用生长速率法、琼脂扩散法、活体组织法,分别测定了初始pH 4.5,5.5,6.5,7.0,7.5和8.5培养条件下,X.neamatophila YL001发酵液及其乙酸乙酯提取物的抑菌活性;同时采用HPLC、LC-MS分析了乙酸乙酯提取物中代谢物的差异。【结果】随着初始pH的升高,共生菌发酵液及其乙酸乙酯提取物的抑菌活性也逐步提高。pH8.5时,YL001发酵液对水稻瘟疫病菌(Magnaporthe grisea)、辣椒疫霉病菌(Phytophthora capsici)、番茄灰霉病菌(Botrytis cinerea)、苹果轮纹病菌(Physalospora piricola)、番茄早疫病菌(Alternaria solani)、甘蓝黑斑病菌(Alternaria brassicae)以及枯草芽孢杆菌(Bacillus subtilis)均具有最强的抑制作用,发酵液乙酸乙酯提取物对番茄灰霉病的EC50为1.29mg/mL,对枯草芽孢杆菌的抑菌圈直径为14.65mm。随着初始培养pH的升高,YL001发酵液及乙酸乙酯提取物对番茄灰霉病的治疗和保护作用也逐渐提高,保护作用明显优于治疗作用。HPLC和LC-MS代谢分析表明,pH8.5、pH 7.0及pH 4.5培养条件下发酵液乙酸乙酯提取物中代谢物含量存在显著差异。【结论】初始培养pH可以显著影响X.neamatophila YL001的抑菌活性及代谢能力,碱性条件更有利于活性物质的产生及其稳定性的保持。  相似文献   

添加玉米秸秆及其生物质炭对砖红壤N₂O排放的影响   总被引：5，自引：2，他引：3  

潘凤娥  胡俊鹏  索龙  王小淇  季雅岚  孟磊 《农业环境科学学报》2016,35(2):396-402

为比较秸秆和生物质炭对土壤氧化亚氮排放的影响,利用室内培养试验研究生物质炭、秸秆添加对土壤性质、硝化作用及N_2O排放的影响。试验设生物质炭、秸秆和空白3个处理,试验培养条件为30℃和75%田间持水量。结果表明,添加秸秆和生物质炭显著提高土壤pH、有机碳和速效K含量,其中秸秆对土壤pH的增加作用更为突出。与对照(1 604.82±168.93μgN_2O-N·kg~(-1))相比,添加秸秆和生物质炭减少N_2O排放量分别为58.0%和65.6%,但二者减排机理不同;秸秆对N_2O的减排因生物的氮固定,降低了硝化反应底物的有效性,生物质炭对N_2O减排可能源于硝化过程中较低的N_2O产生比例。由于生物质炭显著促进土壤硝化速率,而产生较多的NO_3~-,使得热带地区砖红壤硝态氮的淋失风险增大。  相似文献   

竹柳引种造林试验   总被引：1，自引：0，他引：1  

吴远媚  姜立甫  黄雪芬  陈新华  潘涛 《湖南林业科技》2016,(3):75-78

对不同造林密度下3年生竹柳的树高、地径与保存率进行了研究,并与桉树进行比较。结果表明:3年生竹柳的树高、地径及保存率在各密度处理间无显著差异,说明密度处理对竹柳的生长无显著影响。桉树的树高年平均增长量和地径年平均增长量分别比竹柳高出3.456 m和2.355 cm,均存在极显著差异。造林3年后,桉树和竹柳的保存率无显著差异。  相似文献   

临洮县生产建设项目弃渣场土壤流失特征——以肖家河水电站二期工程为例   总被引：1，自引：1，他引：0  

王大为  王立  王小平  曲富荣 《水土保持通报》2016,36(4):51-55

[目的]探讨水电类生产建设项目弃渣场坡面水土流失特性,为黄土丘陵区生产建设项目水土保持综合治理提供科学的理论依据。[方法]以甘肃省定西市临洮县2013年降雨数据为依托,通过肖家河水电站二期工程径流小区对不同处理下的水土流失特征进行研究。[结果](1)临洮县2013年降水量为580.2mm,定义为平雨年;(2)研究区降雨量和平均降雨强度的乘积与土壤侵蚀量呈线性正相关关系(相关系数大于0.85);(3)不同植被类型对弃渣场水土流失有影响,其中油松与苜蓿混播能有效降低土壤侵蚀量和径流量;(4)表层土前期含水量对弃渣场土壤流失量有显著影响,下层土前期含水量对弃渣场土壤流失量无显著影响。[结论]水电类生产建设项目弃渣场土壤流失受降雨量和降雨时间乘积、植被类型和表层土前期土壤含水量的影响。  相似文献   

New insights into radiata pine seedling root infection by Fusarium circinatum          下载免费PDF全文

N. Martín‐Rodrigues  J. Sanchez‐Zabala  I. Salcedo  J. Majada  C. González‐Murua  M. K. Duñabeitia 《Plant pathology》2015,64(6):1336-1348

Pine root infection by Fusarium circinatum has been reported in the literature, but the underlying pathogenic interaction is poorly understood. A green fluorescent protein (GFP)‐tagged F. circinatum isolate, together with confocal microscopy, was used in order to monitor the events associated with root infection of Pinus radiata seedlings. It was found that in order to reach and successfully infect pine roots, F. circinatum employed features that are similar to those previously described for other root‐infecting pathogens, such as mycelial strands, single runner hyphae and simple hyphopodia as well as other features that are reminiscent of those that are known to be involved in biotrophic invasion, such as bulbous invasive hyphae and filamentous invasive hyphae. Abundant sporulation was observed at the root surface as well as inside tracheids both in roots and in the root collar region. The fungus can spread from the roots to the aerial parts of the plant, and once there, colonization appears to be similar to the process that occurs when the pathogen is inoculated in the stem. Wilting symptoms and plant demise may be the result of a reduction in water uptake by roots and of the blockage of the vascular system by fungal hyphae and resin.  相似文献   

Suitability of tef varieties in mixed wheat flour bread matrices: A physico-chemical and nutritional approach     

《Journal of Cereal Science》2015

Wheat flour replacement from 0 to 40% by single tef flours from three Ethiopian varieties DZ-01-99 (brown grain tef), DZ-Cr-37 (white grain tef) and DZ-Cr-387 (Quncho, white grain tef) yielded a technologically viable ciabatta type composite bread with acceptable sensory properties and enhanced nutritional value, as compared to 100% refined wheat flour. Incorporation of tef flour from 30% to 40% imparted discreet negative effects in terms of decreased loaf volume and crumb resilience, and increase of crumb hardness in brown tef blended breads. Increment of crumb hardness on aging was in general much lower in tef blended breads compared to wheat bread counterparts, revealing slower firming kinetics, especially for brown tef blended breads. Blended breads with 40% white tef exhibited similar extent and variable rate of retrogradation kinetics along storage, while brown tef-blended breads retrograded slower but in higher extent than control wheat flour breads. Breads that contains 40% tef grain flour were found to contain five folds (DZ-01-99, DZ-Cr-387) to 10 folds (DZ-Cr-37) Fe, three folds Mn, twice Cu, Zn and Mg, and 1.5 times Ca, K, and P contents as compared to the contents found in 100% refined wheat grain flour breads. In addition, suitable dietary trends for lower rapidly digestible starch and starch digestion rate index were met from tef grain flour fortified breads.  相似文献   

Potential secondary inoculum sources of Botrytis cinerea and their influence on bunch rot development in dry Mediterranean climate vineyards     

Carlos Calvo‐Garrido  Josep Usall  Inmaculada Viñas  Philip AG Elmer  Elena Cases  Neus Teixidó 《Pest management science》2014,70(6):922-930

  相似文献   

造林初植密度对翅荚木幼龄林木材热值影响的研究   总被引：1，自引：1，他引：0  

童方平李贵  刘振华童琪 《中国农学通报》2011,27(19):10-13

为了研究造林初植密度对翅荚木木材热值等的影响,笔者采用造林初植密度试验与木材采样测试相结合的方法对幼龄翅荚木的生长量、生物量、热值等进行研究。结果表明：4年生翅荚木胸径、树高、生物量等生长量密度效应显著。木材热值密度效应不显著,当翅荚木造林初植密度为10001~40002株/hm2时,其单木热值约18200 J/g;当初植密度为3334~6667株/hm2时,其单木热值约19000 J/g。当翅荚木造林初植密度达40002株/hm2时,4年生翅荚木每hm2生物量达94.2 t,生物总量相当于58.69 t标煤。翅荚木是较好的纤维能源植物。  相似文献   

城区屋面径流水质特征与初期径流量研究     

陈伟伟  方立  卞艳丽  曹惠提 《节水灌溉》2012,(10):27-29,33

研究城区屋面径流水质变化特征和初期径流量,可为有效利用城市雨水、控制非点源污染等提供依据。对新乡市2010年城区屋面3场降雨～径流的水文水质过程进行采样分析,结果表明:①屋面径流系数在0.92～0.98之间,径流形态与降雨过程线类似,二者波动幅度相对较小;②各指标标准差率呈SS>COD>DO>pH值的趋势,这与各自含量变化过程的指向性一致;③径流中主要污染物SS、COD变化趋势基本一致,即随着降雨历时的持续其含量逐渐降低,并趋于一个稳定值;④径流中SS与COD之间的相关性较好,而DO与其之间的相关性较差;⑤场次降雨屋面初期径流量为1～3mm的降雨量或前15～20min的径流量。  相似文献