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1.
The allelopathic water extracts (AWEs) may help improve the tolerance of crop plants against abiotic stresses owing to the presence of the secondary metabolites (i.e., allelochemicals). We conducted four independent experiments to evaluate the influence of exogenous application of AWEs (applied through seed priming or foliage spray) in improving the terminal heat and drought tolerance in bread wheat. In all the experiments, two wheat cultivars, viz. Mairaj‐2008 (drought and heat tolerant) and Faisalabad‐2008 (drought and heat sensitive), were raised in pots. Both wheat cultivars were raised under ambient conditions in the wire house till leaf boot stage (booting) by maintaining the pots at 75% water‐holding capacity (WHC). Then, managed drought and heat stresses were imposed by maintaining the pots at 35% WHC, or shifting the pots inside the glass canopies (at 75% WHC), at booting, anthesis and the grain filling stages. Drought stress reduced the grain yield of wheat by 39%–49%. Foliar application of AWEs improved the grain yield of wheat by 26%–31%, while seed priming with AWEs improved the grain yield by 18%–26%, respectively, than drought stress. Terminal heat stress reduced the grain yield of wheat by 38%. Seed priming with AWEs improved the grain yield by 21%–27%; while foliar application of AWEs improved the grain yield by 25%–29% than the heat stress treatment. In conclusion, the exogenous application of AWEs improved the stay green, accumulation of proline, soluble phenolics and glycine betaine, which helped to stabilize the biological membranes and improved the tolerance against terminal drought and heat stresses.  相似文献   
2.
分别用含0.01%的芸香甙,槲皮素2-十三烷酮的人工饲料连续饲养棉铃虫Heli-coverpaarmigeraHubner1~7代,测定不同处理的棉铃虫种各谷胱甘肽S-转移酶(GST)和乙酰胆碱酯酶(AChE)的活性变化以及幼虫对杀虫剂的反应,以单独人工饲料养的各种作对照,芸香甙F1代对甲基硫磷的耐药性提高3倍,槲皮素F1,F2代和2-十三烷酮F1代对甲基对硫磷的耐药性有所提高,对灭多威和溴氰菊酯  相似文献   
3.
Summary

The importance, characteristics, positive and negative impacts, and future role of weeds as an integral part of the natural and agroecosystems are evaluated and discussed. Interference between plants in nature and the importance of differentiating between competition and allelopathy are interpreted. Allelopathy as one component of weed/crop interference, allelochemicals from weed species and their possible mechanism of action are listed and discussed. Weed species with inhibitory action against cultivated crops, other weed species, and plant pathogens, as well as self-inhibitory (autopathic) species are reviewed. Stimulatory or inhibitory allelopathic effects of different crop plants, trapping and catching species, and the potential of allelopathic weeds in inhibiting or stimulating certain parasitic weed species are discussed and evaluated. Allelopathy as a mechanism and future strategy for agricultural pest control and farm management and the potential use and development of some allelochemicals as natural pesticides or plant growth regulators are also considered and discussed.  相似文献   
4.
辣椒根系分泌物的化感作用及其化感物质分析   总被引:9,自引:1,他引:8  
 利用生物测定和GC-MS分析的方法,研究了辣椒根系分泌物各组分的化感作用及其优势组分的化感物质。结果表明:辣椒根系分泌物各组分对莴苣的化感作用不同,以乙醚洗脱组分的化感作用最强;对乙醚洗脱组分进行再分离,最后得出80%乙醚+20%乙酸乙酯洗脱组分的化感作用最强;对80%乙醚+20%乙酸乙酯洗脱组分进行GC-MS分析鉴定,确定辣椒根系分泌的主要化感物质为邻苯二甲酸二丁酯、邻苯二甲酸-丁基-环己烷基酯、邻苯二甲酸-丁基-异丁酯、邻苯二甲酸二叔丁酯、二苯胺、4,4’-叔丁基二苯酚、苯萘胺、邻苯二甲酸,其中,邻苯二甲酸二丁酯的含量最高。  相似文献   
5.
采用有机溶剂浸提和水授提2种方式分别提取苦槠叶、根的生化物质,并用闽楠种子发芽试验评价苦槠对闽楠的化感作用.结果表明,2种方式浸提的苦槠叶和根的生化物质对闽楠种子的各项发芽指标均表现为一定程度的抑制作用.说明从生化角度看苦槠与闽楠的种间关系并不十分协调.  相似文献   
6.
Mechanism of action of insecticidal secondary metabolites of plant origin   总被引:1,自引:0,他引:1  
Insect pest management is facing the economic and ecological challenge worldwide due to the human and environmental hazards caused by majority of the synthetic pesticide chemicals. Identification of novel effective insecticidal compounds is essential to combat increasing resistance rates. Botanicals containing active insecticidal phytochemicals appear to be promising to address some of these problems. Therefore, there is a continuous need to explore new active molecules with different mechanisms of action. Secondary metabolites present in plants apparently function as defense (toxic), which inhibits reproduction and other processes. The phytochemical biomolecules could be used for maximizing the effectiveness and specificity in future insecticide design with specific or multiple target sites, while ensuring the economic and ecological sustainability. In this article, the current state of knowledge on phytochemical sources and insecticidal activity, their mechanism of action in insects, resistance, and promising advances made in phytochemical research are reviewed.  相似文献   
7.
Stylosanthes guianensis is a popular pasture legume and cover crop. The legume possessed strong allelopathic potential and suppressed spontaneous growth of paddy weeds. In a bioassay, aqueous extract of S. guianensis remarkably inhibited germination and growth of barnyardgrass and monochoria. Application of 1 ton ha?1 upland parts of S. guianensis significantly reduced paddy weed biomass by 80 % and increased rice yield by 40 % when compared with the control. Gas chromatography‐mass spectrometry analysis reveals the presence of several allelochemicals in S. guianensis including phenolic acids, coumarin and long‐chain fatty acids. Stylosanthes guianensis may be used as a source of natural herbicide for reducing the dependency on synthetic herbicides in agricultural production.  相似文献   
8.
大蒜根系分泌物化感作用及化感物质的比较   总被引:1,自引:0,他引:1  
【目的】利用生物测定和GC-MS分析方法,研究大蒜根系分泌物的化感作用及化感物质。【方法】采用琼脂培和砂培2种栽培方式收集大蒜根系分泌物,分别采用乙醚、乙酸乙酯、三氯甲烷和正丁醇4种有机溶剂进行萃取分离,对各有机溶剂萃取液进行萝卜种子发芽试验,确定出强化感作用组分,并对其成分进行GC-MS分析。【结果】各有机溶剂萃取液的化感作用强弱顺序依次为:乙酸乙酯萃取液>三氯甲烷萃取液>正丁醇和乙醚萃取液,初步确定大蒜根系分泌物中的化感物质为2,6-二异丙基苯酚、2,6-二叔丁基对甲酚和二烯丙基二硫醚。【结论】2种栽培方式收集的大蒜根系分泌物的乙酸乙酯组分中的成分相似,但在含量上差异较大,表现为砂培>琼脂培。  相似文献   
9.
花生化感物质降解菌的筛选、鉴定与降解特性研究   总被引:1,自引:1,他引:0  
为筛选高效化感物质降解菌,以花生根系分泌物中的化感物质苯甲酸作为唯一碳源,采用富集培养和稀释平板法从连作花生长期定位试验地的健康花生植株根际土壤中筛选高效花生化感物质降解菌,经形态观察、生理生化分析和16S rDNA序列同源性比较以及系统发育分析对降解菌进行鉴定,并通过单因素试验对降解菌进行降解特性研究。结果表明:筛选到的2株高效降解菌分别为木糖氧化无色杆菌(Achromobacter xylosoxidans HJ-2)和硝基还原假单胞菌(Pseudomonas nitroreducens HJ-3)。降解菌HJ-2降解的适宜pH为6.0~9.0,适宜温度为30~45℃,适宜NaCl浓度为0~6%;降解菌HJ-3降解的适宜pH为6.0~8.0,适宜温度为30~35℃,适宜NaCl浓度为0~4%。两株降解菌都能够降解苯乙酮、硬脂酸、棕榈酸、乳酸、3,5-二甲基苯甲醛和丙三醇等化感物质。研究表明,降解菌HJ-2和HJ-3对苯甲酸有显著降解效果,两个菌株均具有广谱降解化感物质的特性,且降解菌HJ-2对不良环境适应能力较强。  相似文献   
10.
作物化感品种对农田杂草的调控   总被引:3,自引:0,他引:3  
农田施用大量除草剂不仅引起环境和生态问题,而且导致除草剂抗性杂草不断发生。因此,需要建立生态安全的杂草管理策略以改变杂草控制对除草剂依赖的现状。利用作物化感品种调控农田杂草是极具开发潜力的杂草控制策略,这些作物化感品种自身能够产生和释放化感物质调控杂草,从而减少对人工除草剂的依赖。鉴于此,近10余年来,以作物化感品种为中心的农田杂草控制策略一直得到广泛的关注和研发。本文综述了作物化感品种调控农田杂草和相应抑草机制的最新进展,尤其是可商业化种植的作物化感新品种选育及其在除草剂减量控制杂草的实践。在此基础上,阐释了作物化感品种间亲属合作行为以及基于化感物质的新型除草剂研发对解决农田杂草难题的机遇和挑战。  相似文献   
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