共查询到20条相似文献，搜索用时 78 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
石羊河流域的水资源及其公众的水意识 总被引：1，自引：1，他引：0
在石羊河流域属资源性缺水地区,相比较而言其上下游的耕地数量与其产流量成反比。农民普遍采取有水就灌的灌水方式,存在水资源浪费现象。大多数公众对水资源的认识仅凭自己的用水情况来判断。若农民灌溉河水,水资源严格受到水利部门的控制,大多数人认为水资源不够用,若利用井水灌溉,灌水者基本自己决定用水的数量和灌水时间,灌水者感觉水资源并未受到限制,水是充足的。在石羊河流域中下游地区,因有井水的支持而导致51.97%-64.06%的人认为水资源够用,也就使人认为有井即有水。在这种思想引导下,人们便疯狂的打井,无节制的抽取地下水。石羊河流域水资源管理部门在指导和保护水资源行为的同时,应加强流域水资源现状、利用和管理的宣传,使流域内绝大多数人懂得区域水资源的现状、利用方式、开发潜力,自觉形成节约用水、科学用水、持续用水的意识。 相似文献
12.
13.
社会学习、环境认知对农户亲环境行为影响研究 总被引：1，自引：0，他引：1
基于山东、陕西、甘肃省710份调研数据,通过结构方程模型分析社会学习、环境认知对农户亲环境行为的影响.结果表明:(1)环境认知能够直接正向影响农户亲环境行为,标准化路径系数为0.090;(2)社会学习对农户亲环境行为有直接负向影响,并通过环境认知也会间接负向影响农户亲环境行为,标准化路径系数分别为-0.400、-0.0... 相似文献
14.
生态文明建设关系着中国梦的实现和中华民族的永续发展。生态文明是公众的基本素养,公众是生态文明体系建设的基本群体。基于新冠疫情期的线上1867份调查问卷,运用结构方程和多元线性回归模型考察了公众生态文明认知-行为特征,分析了认知-行为的逻辑路径、影响因素及城乡差异。结果表明:客观条件对公众生态文明内涵认识、认知态度以及参与意愿有正向影响,内涵认识通过中介变量认知态度对参与意愿产生正向影响;性别、年龄、学历、居住地、家庭经济对公众认知-行为影响显著,自我判断家庭经济情况对城镇公众的生态文明建设参与意愿影响显著,疫情期间的身体状况对乡村公众的认知-行为影响显著。结果提示:应着力改善区域生态环境,进一步加强公众生态文明宣传教育,重视提升公众的基本素质,制定城乡差异化的生态文明宣传教育策略,增强特殊事件期的公众生态文明行为引导。 相似文献
15.
Virulence of Hymenoscyphus albidus and native and introduced Hymenoscyphus fraxineus on Fraxinus excelsior and Fraxinus pennsylvanica 
下载免费PDF全文
下载免费PDF全文 Ash dieback is caused by Hymenoscyphus fraxineus, a cryptic species of the putatively harmless Hymenoscyphus albidus. Recently, H. fraxineus was found to be native to East Asia. However, the virulence of Asian H. fraxineus strains on Fraxinus excelsior and the virulence of European H. albidus on hosts other than F. excelsior and Fraxinus mandshurica have not yet been assessed. In a wound inoculation study, the virulence of four H. albidus and four European and Japanese H. fraxineus strains was assessed on F. excelsior and Fraxinus pennsylvanica in a climate chamber. Lesion lengths were measured after approximately three and a half months. No lesions were observed on the negative control or on trees inoculated with H. albidus. In contrast, inoculation with H. fraxineus induced typical symptoms of ash dieback on both tree species. Japanese H. fraxineus strains induced significantly longer lesions compared to European strains. Fraxinus excelsior was highly susceptible and developed lesions averaging lengths of 1·7 and 8·4 cm for European and Japanese strains, respectively. Fraxinus pennsylvanica was less susceptible and developed average lesion lengths of 1·6 and 4·8 cm for European and Japanese strains, respectively. Most strains were successfully reisolated from necrotic lesions or inocula, fulfilling Koch's postulates. The data show that additional introductions of H. fraxineus strains from the native range to Europe could pose a threat to the conservation of F. excelsior. In addition, introduction of H. fraxineus to North America could potentially have a negative effect on the indigenous F. pennsylvanica. 相似文献
16.
Romina G. Rosati Rocío S. Ramos María M. Scandiani Alicia G. Luque Claudia P. Spampinato 《Plant pathology》2021,70(2):407-416
Sudden death syndrome (SDS) of soybean is a fungal disease caused by at least four distinct Fusarium species: F. tucumaniae, F. virguliforme, F. brasiliense, and F. crassistipitatum. All four species are present in Argentina. These fungi are soilborne pathogens that only colonize roots and cause root necrosis. However, damage also reaches the aboveground part of the plant, and foliar chlorosis and necrosis, followed by premature defoliation, can be observed. Although the pathogenicity and phytotoxicity of F. virguliforme has been well characterized, knowledge regarding disease development by other fungal species is scarce. In this study, two plant species, soybean (Glycine max) and Arabidopsis thaliana, and isolates from two fungal species, F. tucumaniae and F. crassistipitatum, were used to comparatively analyse the fungal pathogenicity and the phytotoxicity of volatile organic compounds (VOCs) and cell-free culture filtrates. Fungal inoculation had a significant effect on plant growth, regardless of the plant species. In addition, infected soybean plants showed disease incidence and foliar and root symptoms. Inhibition of A. thaliana growth was not due to VOCs emitted by fungi. Instead, both pathogens were shown to produce toxins that caused typical SDS foliar symptoms in soybean and root length reduction in A. thaliana. As far as we know, this is the first report that demonstrates that F. tucumaniae and F. crassistipitatum affect A. thaliana growth and emit VOCs, and that F. crassistipitatum produces toxins. 相似文献
17.
为寻找高活性的米尔贝霉素衍生物,以伊维菌素为原料,经脱糖、羟基保护、氧化、还原胺化、脱保护等将其转变为13-氨基米尔贝霉素类似物,通过三组分反应设计合成了一系列米尔贝霉素磺酰脒类化合物(7a~7i),并初步测定了其对朱砂叶螨Tetranychus cinnabarinus和豆蚜Aphis craccivora的室内活性。结果表明:各衍生物对朱砂叶螨和豆蚜均有较好的触杀活性,其中7f、7h和7i对朱砂叶螨24 h的LC50值分别为1.04×10–2、9.60×10–4和1.44×10–2 mg/L;7i对豆蚜24 h的LC50值为7.81 mg/L。米尔贝霉素13位氨基上磺酰化的结构修饰有助于提高米尔贝霉素类化合物的杀螨、杀蚜活性。 相似文献
18.
Anil Shrestha Katrina M. Steinhauer Bradley D. Hanson Marie Jasieniuk Kurt J. Hembree Steven D. Wright 《国际虫害防治杂志》2016,62(4):300-307
The growth and phenological development of spring- and fall-planted Conyza canadensis and C. bonariensis were studied in Fresno, CA, USA. A glyphosate-resistant (GR) and a glyphosate-susceptible (GS) population of each species were used. Time taken by each plant to reach the rosette, bolting, appearance of first bud, appearance of first open flower, and initial seed set were converted to growing degree days (GDDs). The fall- and spring-planted C. canadensis required similar GDDs to complete their life cycles but the GR type required fewer GDDs than the GS type. In C. bonariensis, the GDDs required to complete its life cycle differed between the fall- and spring-plantings but not between the GR and GS types. The total aboveground biomass of both fall- and spring-planted Conyzas at initial seed set was similar but the spring-planted GS C. canadensis produced more biomass than the GR type, whereas the fall-planted GS C. bonariensis produced more biomass than the GR type. Plant development based on GDD models can have global implications and help in planning for timely applications of post-emergence herbicides. 相似文献
19.
Y. Elead J. Köhl N. J. Fokkema 《European journal of plant pathology / European Foundation for Plant Pathology》1994,100(5):315-336
Sixty isolates of saprophytic microorganisms were screened for their ability to reduce the severity of grey mould (Botrytis cinerea) infection and sporulation. Isolates of the bacteriaXanthomonas maltophilia, Bacillus pumilus, Lactobacillus sp., andPseudomonas sp. and the fungusGliocladium catenulatum reduced germination of conidia of the pathogen and controlled disease on bean and tomato plants. Their activity under growth room conditions was good, consistent, and similar to the activity of the known biocontrol agent,Trichoderma harzianum T39 (non-formulated). Although the tested isolates may for nutrients with the germinating conidia ofB. cinerea, resistance induced in the host by live or dead cells were also found to be involved. Inhibitory compounds were not detected on treated leaves. Sporulation ofB. cinerea after its establishment on leaves was also reduced by the above mentioned isolates and byPenicillium sp.,Arthrinium montagnei, Ar. phaeospermum, Sesquicillium candelabrum, Chaetomium globosum, Alternaria alternata, Ulocladium atrum, andT. viride. These sporulation-inhibiting fungi did not reduce the infection of leaves byB. cinerea. Most of these selected fungi and bacteria were capable of reducing lesion expansion. 相似文献
20.
探究不同矿化度咸淡水混合喷灌对冬小麦、夏玉米生长及产量的影响,并通过监测土壤水盐分布状况来选择适宜矿化度的咸淡水灌溉方式。在河北低平原地区开展大田灌溉试验,研究了淡水畦灌、淡水喷灌、2 g·L-1和3 g·L-1咸水与淡水混合喷灌对小麦、玉米生长及土壤水盐运移的影响。结果表明：与淡水喷灌相比,连续两年灌溉后,小麦收获时2 g·L-1和3 g·L-1矿化度咸淡混合水喷灌处理的根层（0~40 cm）土体含盐量平均分别增加了17.8%和42.7%,0~100 cm土体含盐量平均分别增加了32.9%和74.3%,玉米收获时根层土体含盐量平均分别增加了40.3%和86.9%,0~100 cm土体含盐量平均分别增加了39.0%和88.9%,且3 g·L-1矿化度咸淡混合水喷灌处理的盐分累积已超出小麦和玉米生长的盐分阈值。2 g·L-1矿化度处理的冬小麦产量较淡水喷灌处理降低了9.8%~11.4%（差异不显著）,但3 g·L-1矿化度处理比淡水喷灌处理的产量显著降低了25.0%~25.9%（P<0.05）;2 g·L-1矿化度处理的夏玉米单株穗粒质量和产量较淡水喷灌处理分别降低了5.1%~10.4%和6.6%~10.5%（差异不显著）,3 g·L-1矿化度比淡水喷灌处理的百粒重、单株穗粒质量和产量分别降低了18.6%~22.4%、18.2%~25.9%和14.7%~15.3%（P<0.05）,3 g·L-1矿化度对冬小麦和夏玉米的产量构成因素影响显著。因此,咸淡混合水矿化度不大于2 g·L-1的喷灌模式用于该地区冬小麦-夏玉米田间灌溉是可行的。 相似文献