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41.
有机磷农药在农业生产中广泛应用,用气相色谱法进行农药残留检测容易产生基质效应,影响分析结果的可靠性,为研究用气相色谱法进行农残检测过程中有机磷农药在不同蔬菜中的基质效应,选取瓜类、茄果类、叶菜类3类常见蔬菜和13种有机磷农药进行研究,对影响基质效应的因素采取不同变量法进行分析,得出结论:有机磷农药在叶菜类蔬菜中基质效应最大;含有P=O键农药基质效应更强;基质含量越多基质效应越强,并对在检测如何减少基质效应给出了建议.  相似文献   
42.
哈茨木霉在水稻体内的定殖及其对水稻纹枯病抗性的影响   总被引:3,自引:0,他引:3  
以具有抗腈菌唑标记哈茨木霉TUV-13菌株的分生孢子悬浮液对水稻种子分别进行浸种、蘸根、叶面接种,栽培至2叶1芯期,从秧苗各组织分离回收菌株TUV-13。对经菌液处理的秧苗进行显微及超微观察结果表明,浸种处理能使TUV-13菌株在水稻秧苗的根、茎、叶中稳定定殖;而蘸根处理、叶面接种,TUV-13菌株只能在处理的局部区域定殖。TUV-13菌株定殖后,水稻秧苗与抗病相关的酶活性显著提高,对水稻纹枯病防效达82.9%。  相似文献   
43.
Although stable isotope analysis is a powerful tool for determining diet, migration patterns and the structure of food webs in aquatic systems, the slow response of isotopic ratios in the widely used muscle tissue often hampers this approach, particularly in slow‐growing or adult fishes. We conducted a diet‐switch experiment to compare the changes in the stable carbon isotope ratio (δ13C values) in the epidermal mucus and muscle tissue of five‐year‐old catfish (Silurus asotus). The isotope ratios in noninvasively sampled mucus changed more rapidly than those in the muscle tissue. As isotopic change in mucus was relatively rapid, this technique can be used over a finer timescale than traditional isotopic analyses using the muscle tissue. The isotopic change half‐life in our experimental condition was 200 days, which would not be short enough for some research purposes. Examining mucus along with the muscle would enable food habits of slow‐growing fishes to be determined over different timescales. However, the rate of isotopic change in the mucus was negatively affected by the size of fish and was slower than the previously reported rates in juvenile steelhead. These findings suggest that mucus turnover rates need to be determined prior to the field data interpretation.  相似文献   
44.
东13椪柑是1973年通过营养系选种,在广东省杨村华侨柑桔场选出的优良新株系。经过14年来系统的株系比较试验、中间试验及示范推广,证明该株系果大优质、果形高桩美观、早结丰产等性状稳定,综合性状优于目前生产上推广的品种(系)。该株系大面积出口货源基地已在广东省建立,省内外推广面积已超过8000亩。  相似文献   
45.
Abstract

The root parasitic plants Orobanche spp. (broomrapes) seriously affect agricultural production. A visualization and quantitative analytical method for the interception of nutrients was established using a positron-emitting tracer imaging system and 13NO? 3. By using this analytical method that involves volume normalization with 18F? images, the nitrogen nutrient interception ratio of the Orobanche spp. was calculated to be 73.6 ± 3.9% in a host–parasite system of red clover (Trifolium pratense L.).  相似文献   
46.
The Foliar Uptake by Squash Plant

The radioactive ash for experimental use, hereafter referred to as “Bikini ash”, was prepared by igniting the heavily contaminated substances on board No. 5 Fukuryu Maru at about 650°C, followed by sifting through a 100 mesh sieve. On ignition some parts of the fission products, particularly iodine, ruthenium and tellurium would have possibly been lost to the air.  相似文献   
47.
The pro- and anti-inflammatory cytokines create a network of interactions between cells that lead to both stimulatory and inhibitory responses that maintain an effective homeostatic regulation. The anti-inflammatory cytokines are a family of peptides that modulate the pro-inflammatory cytokine response. Cytokines act in concert with non-cytokine mediators, such as prostaglandin E2, glucocorticosteroids, lipocortins, and catecholamines. This review highlights new developments in our understanding of the pathophysiology of inflammation and gives an example of a more recent approach to the modulation of acute systemic inflammatory disorders: activation of 2-adrenergic receptors on macrophages. In this respect the potent 2-adrenergic agonist clenbuterol seems of therapeutic interest.  相似文献   
48.
新蜜13号一代杂种的父本89-4和母本89-1均来自新疆当地厚皮甜瓜红心脆与欧美类型厚皮甜瓜的杂交后代。该品种单瓜重3kg以上,果实椭圆形,成熟果果皮金黄色,果面网纹细致,果肉浅桔红色,中心折光糖14度以上,肉质细、脆、香味浓郁,较耐贮运。成熟期比对照品种皇后提前5~10天,一般667m2产量可达2000~2500kg,对甜瓜枯萎病、蔓枯病、疫霉病有较强的抗性。  相似文献   
49.
50.
The absolute configuration of bisabolanoids isolated from Yaku-sugi wood were compared with those of dihydrocarvone and dihydrocarveol isomers based on their13C nuclear magnetic resonance data and optical rotations.  相似文献   
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