扰动扩散流动分析法测定土壤氮、磷技术研究     

李灿  李振峰  马刘正  张伟  李晓冬  VIJAYA Raghavan  胡建东 《农业环境科学学报》2022,41(8):1846-1854

随着国家对农业面源氮、磷污染防治力度的加大,土壤氮、磷测定技术迫切需要改善。本研究在对常规的扩散对流（Dispersion convection）和强迫对流（Forced convection）流动分析方法基础上,提出了扰动扩散（Perturbation diffusion）流动分析方法,以实现土壤氮、磷全自动化快速测定与分析。扰动扩散流动分析方法是将样品和试剂定量化后集中在化学反应腔中进行反应,然后程序控制蠕动泵对化学反应腔中反应物进行反复扰动,待化学反应完全稳定后流入光电探测单元完成土壤氮、磷含量测定。采用取自湖北潜江的土壤样品对扰动扩散流动分析方法进行了系统验证,实验结果表明,本研究提出的方法与常规紫外可见分光光度法对氮、磷测定相比,基于硫酸钠和碳酸氢钠联合浸提的土壤铵态氮测量值相关系数为0.915 5,基于氯化钙浸提的土壤铵态氮、硝态氮和水溶性磷测量值相关系数分别为0.998 5、0.990 1和0.991 1。铵态氮、硝态氮和水溶性磷的检出限分别为0.055 4、0.020 3 mg·L^-1和0.008 4 mg·L^-1,相对标准偏差（RSD,n=7）分别为1.8%、4.8%和1.0%。  相似文献   

氮锌配施对水稻生长、产量和养分吸收分配的影响   总被引：1，自引：0，他引：1  

李俊丽  钱干  李海星  张丽梅  叶祥盛  徐芳森  蔡红梅 《华中农业大学学报》2021,40(3):159-167

为研究氮锌配施对水稻生长、产量和养分吸收分配的影响,采用大田小区试验,以籼型杂交稻品种广两优35和常规粳稻品种日本晴为研究材料,设置3个锌水平和4个氮水平的交互处理,分析了各生育期水稻的生物量,成熟期产量及构成因素,各部位氮和锌的含量、累积量和分配比例。结果表明,氮锌配施对水稻早期的生长和后期的产量形成均具有协同增效效应,这种效应在不同水稻品种中具有一定的差异性。氮锌配施对水稻每公顷穗数具有极显著的正向交互效应,每公顷穗数的显著增加是氮锌配施下水稻产量提高的主要原因。氮锌配施不仅提高了水稻植株中的氮和锌含量,同时还促进了氮和锌向生殖器官(小穗)中分配,这可能是水稻产量提高的主要生理机制之一。  相似文献   

Deadly Outbreak of Iron Storage Disease (ISD) in Italian Birds of the Family Turdidae     

Silvia PAVONE  Sonia SALAMIDA  Ivan PECORELLI  Elisabetta ROSSI  Elisabetta MANUALI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2014,76(9):1209-1212

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饲料添加砷制剂对小鼠铁吸收的影响     

何万领  李晓丽  李元晓  李旺  杨自军 《兽医大学学报》2014,(2):328-330

为探讨饲料中添加砷制剂对小鼠铁吸收的影响,45只小鼠被随机分为3组,各组在基础日粮中分别添加0,40,80mg／kg砷（以洛克沙胂形式）,试验期30d。试验结束后,收取各组粪便和组织器官测定铁含量。结果显示,与对照组相比,40mg／kg砷组铁表观吸收率提高14．57％,80mg／kg砷组铁表观吸收率则降低了14．93％;40mg／kg砷组小鼠肝脏、肾脏、脾脏、小肠和腿肌铁含量显著升高（P〈O．05）,80mg／kg砷组则显著降低（P〈O．05）;但两组分别于停砷后5,7d,组织器官铁恢复正常水平。这表明40mg／kg砷水平可促进铁的吸收,相反80mg／kg砷水平则抑制铁的吸收。  相似文献   

Using a stand-level model to predict light absorption in stands with vertically and horizontally heterogeneous canopies     

David I Forrester  Rubén Guisasola  Xiaolu Tang  Axel T Albrecht  Tran Lam Dong  Guerric Ie Maire 《中国林学(英文版)》2014,1(3):158-176

Background： Forest ecosystem functioning is strongly influenced by the absorption of photosynthetically active radiation （APAR）, and therefore, accurate predictions of APAR are critical for many process-based forest growth models. The Lambert-Beer law can be applied to estimate APAR for simple homogeneous canopies composed of one layer, one species, and no canopy gaps. However, the vertical and horizontal structure of forest canopies is rarely homogeneous. Detailed tree-level models can account for this heterogeneity but these often have high input and computational demands and work on finer temporal and spatial resolutions than required by stand-level growth models. The aim of this study was to test a stand-level light absorption model that can estimate APAR by individual species in mixed-species and multi-layered stands with any degree of canopy openness including open-grown trees to closed canopies. Methods： The stand-level model was compared with a detailed tree-level model that has already been tested in mixed-species stands using empirical data. Both models were parameterised for five different forests, including a wide range of species compositions, species proportions, stand densities, crown architectures and canopy structures. Results： The stand-level model performed well in all stands except in the stand where extinction coefficients were unusually variable and it appears unlikely that APAR could be predicted in such stands using （tree- or stand-level） models that do not allow individuals of a given species to have different extinction coefficients, leaf-area density or analogous parameters. Conclusion： This model is parameterised with species-specific information about extinction coefficients and mean crown length, diameter, height and leaf area. It could be used to examine light dynamics in complex canopies and in stand-level growth models.  相似文献   

菠萝叶纤维与其它植物纤维的吸湿性能对比测试及分析     

连文伟  张劲  薛忠  李明福  黄涛 《绿色科技》2014,(10)

利用扫描电镜、X射线衍射等测试方法对菠萝叶纤维、亚麻纤维、苎麻纤维和棉花纤维的微观形态结构进行了分析。分析认为:菠萝叶纤维的形态结构有区别于其它三种植物纤维,有较大的比表面积;菠萝叶纤维的结晶度与亚麻纤维和苎麻纤维接近,高于棉花纤维。在热带标准状态下,采用烘箱干燥法和回归模型分析法,对测试的四种进行了吸湿、放湿测试与分析。结果表明:在吸湿性能方面,菠萝叶纤维表现最佳,棉花纤维最差;在纤维吸湿平衡回潮率和吸湿速率方面,菠萝叶纤维与亚麻纤维和苎麻纤维相近,且高于棉花纤维;在纤维放湿平衡回潮率和放湿速率方面,菠萝叶纤维高于亚麻纤维、苎麻纤维和棉花纤维。  相似文献   

Bioavailability of amino acids chelated and glass embedded zinc to rainbow trout, Oncorhynchus mykiss, fingerlings     

M.J. Apines  S. Satoh  V. Kiron  T. Watanabe  N. Nasu  & S. Fujita 《Aquaculture Nutrition》2001,7(4):221-228

A 2 × 4 factorial experiment was conducted to determine the bioavailability of zinc (Zn) from amino acids chelated (Zn–Am) and glass embedded Zn (Zn–Gl) as sources for rainbow trout, Oncorhynchus mykiss , fed practical type diets. Two levels of Zn (20 and 40 mg kg⁻¹) were supplemented to the diets using either zinc sulphate (Zn–Sf), zinc methionine (Zn–Mt), Zn–Am or Zn–Gl. Rainbow trout with an average weight of 2 g were fed the experimental diets for 15 weeks. Growth and feed gain ratio (FGR) were not significantly influenced by the dietary Zn content and forms. Alkaline phosphatase (ALP) activity for both levels of Zn–Am was significantly higher than that of Zn–Sf and Zn–Gl at 20 mg supplementation. In another experiment, fish of about 95 g were fed the same experimental diets to determine the absorption of Zn and it was found to be significantly higher from Zn–Am compared with the rest. Retention from Zn–Am at 20 mg was significantly higher than the rest, excluding Zn–Sf. The results suggest that the availability of Zn from Zn–Am might be superior among the sources compared.  相似文献   

挤压膨化与改性处理海带渣的油污吸附特性试验   总被引：1，自引：0，他引：1  

李莎  张国琛  李秀辰  张倩  母刚  于鹏 《大连海洋大学学报》2014,(4):413-419

利用挤压膨化和改性处理的海带渣进行了油污吸附材料制备的试验研究,探讨了海带渣粒度和玉米碴添加量对挤压膨化海带渣油污吸附特性的影响,以及硬脂酸添加量、海带渣粒度和改性时间对改性海带渣油污吸附特性的影响。研究表明：增加玉米碴添加量,可提高挤压膨化海带渣的吸油率、吸油速率和漂浮率,但吸水率亦提高;海带渣粒度越小,挤压膨化后的海带渣吸油和漂浮效果越好,越不易吸水;当海带渣粒度为0.9 mm、玉米碴添加量为30%时,挤压膨化海带渣具有良好的油污吸附效果,其吸油率、吸油速率和漂浮率分别为142.8%、94.1%和49.4%,吸水率为89.2%。改性试验结果表明：硬脂酸改性可显著提高海带渣的漂浮率,降低其吸水率,但油污吸附效果随硬脂酸添加量的增加而下降;选择粒度较小的海带渣并且保证一定的改性时间,有利于提高油污吸附效果;当海带渣粒度为0.9 mm、硬脂酸添加量为8.5%、改性处理2 h时,海带渣的吸油率、吸油速率和漂浮率分别为217.5%、94.3%、94.0%,吸水率在31.0%以下,吸油率和漂浮率分别是挤压膨化海带渣的1.52倍和1.90倍,吸水率降低了65.2%。  相似文献   

不同温度下刺参对有机沉积物的摄食与吸收   总被引：4，自引：1，他引：4  

赵永军  张慧 《水产科学》2004,23(7):1-4

以常规实验生态方法,研究了不同温度下不同规格刺参对有机沉积物的摄食与吸收,在水温为13 2～22 3℃时,大、中、小3种规格刺参对有机沉积物平均摄食率[g/(g·h)]依次为0 00324,0 00648,0 00959,对有机沉积物平均吸收率依次为7 32%,13 49%,17 61%。温度为15 13℃时,大规格刺参的吸收率最高(15 32%);当温度上升到23 2℃,中、小两种规格刺参吸收率达最高(依次为23 56%、26 49%)。刺参对沉积物中有机物的吸收与利用,降低了水底有机物的含量,可有效抑制水体有害物质的积累及产生。  相似文献   

Biochemistry and physiology of a family of eel natriuretic peptides   总被引：1，自引：0，他引：1  

Yoshio Takei  Richard J. Balment 《Fish physiology and biochemistry》1993,11(1-6):183-188

Three natriuretic peptides with similar structures were isolated from eels and their amino acid sequences determined; atrial natriuretic peptide (ANP) from atria, ventricular natriuretic peptide (VNP) from ventricles, and C-type natriuretic peptide (CNP) from brains. All three hormones were circulating in eel blood, and their plasma levels invariably decreased when eels were transferred from fresh water (FW) to seawater (SW). Eel ANP and VNP inhibited drinking in FW and SW eels. Eel ANP inhibited water and Na⁺ absorption by the intestine of SW eels. The potency of these ANP effects was 2–3 orders greater than those of other hormones which are known to have similar effects. Eel ANP and VNP induced antidiuresis but not antinatriuresis in FW eels. Eel ANP increased plasma cortisol level in SW eels but not in FW eels. The antidiuretic effect and the stimulation of cortisol secretion in eels are opposite to the ANP effects reported in mammals. These data suggest that ANP plays a complex role in the eel osmoregulation.

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Résumé Trois peptides natriurétiques présentant des structures similaires ont été isolés chez l'anguille et leurs séquences en acides aminés a été déterminées; le peptide atrial natriurétique (ANP) dans l'atria, le peptide ventriculaire natriurétique (VNP) dans les ventricules et le peptide natriurétique de type C dans le cerveau. Ces trois hormones sont présents dans le sang d'anguille et leur niveau plasmatique decroit invariablement quand les anguilles sont transférées d'eau douce en eau de mer. L'ANP et le VNP d'anguille inhibent l'action de boire chez les anguilles d'eau douce et d'eau de mer. L'ANP d'anguille inhibe l'absorption d'eau et de Na⁺ par l'intestin d'anguille en eau de mer. Ces effets de l'ANP sont 2 à 3 fois plus grands que ceux observés avec d'autres hormones qui sont connues pour avoir des effets similaires. L'ANP et le VNP d'anguille induisent l'antidiurèse mais pas l'antinatriurèse chez les anguilles d'eau douce. L'ANP d'anguille augmente chez ce poisson les niveaux de cortisol plasmatique en eau de mer mais pas en eau douce. L'effet antidiurétique et la stimulation de la sécrétion de cortisol chez l'anguille sont contraire aux effets de l'ANP observés chez les mammifères. Ces résultats suggèrent que l'ANP joue un role complexe dans l'osmorégulation de l'anguille.

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