Predicting water permeability in sedimentary rocks from capillary imbibition and pore structure

In this paper, absolute water permeability is estimated from capillary imbibition and pore structure for 15 sedimentary rock types. They present a wide range of petrographic characteristics that provide degrees of connectivity, porosities, pore size distributions, water absorption coefficients by capillarity and water permeabilities. A statistical analysis shows strong correlations among the petrophysical parameters of the studied rocks. Several fundamental properties are fitted into different linear and multiple expressions where water permeability is expressed as a generalized function of the properties. Some practical aspects of these correlations are highlighted in order to use capillary imbibition tests to estimate permeability. The permeability–porosity relation is discussed in the context of the influence of pore connectivity and wettability. As a consequence, we propose a generalized model for permeability that includes information about water fluid rate (water absorption coefficient by capillarity), water properties (density and viscosity), wetting (interfacial tension and contact angle) and pore structure (pore radius and porosity). Its application is examined in terms of the type of pores that contribute to water transport and wettability. The results indicate that the threshold pore radius, in which water percolates through rock, achieves the best description of the pore system. The proposed equation is compared against Carman–Kozeny's and Katz–Thompson's equations. The proposed equation achieves very accurate predictions of the water permeability in the range of 0.01 to 1000 mD.

Quantification of storage proteins during seed imbibition of native species from the brazilian Caatinga vegetation.

Poincianella pyramidalis (Fabaceae), Schinopsis brasiliensis (Anacardiaceae) and Sideroxylon obtusifolium (Sapotaceae) are native species of the Caatinga vegetation from Northeastern Brazil and have both biological importance and potential economic uses. Little is known about the water uptake and degradation of storage proteins during seed germination of these species. The aim of this study was to evaluate the imbibition and quantify the amount of storage proteins during seed germination of P. pyramidalis, S. brasiliensis and S. obtusifolium. Two lots of S. obtusifolium seeds with different vigour were used. Four replicates of 20 seeds of P. pyramidalis, S. brasiliensis and S. obtusifolium, were sown onto gerboxes with blotting paper soaked in distilled water and incubated during 72, 200 and 624 hours. Before and after imbibition seeds were weighed and frozen at until the sequential extraction and analysis of the seed storage proteins. Based on our results, we conclude that seed germination of P. pyramidalis, S. brasiliensis and S. obtusifolium has a well-defined triphasic imbibition. All storage proteins content of P. pyramidalis and S. brasiliensis seeds degraded along with the seed imbibition. Likewise, the content of albumins, globulins and glutelins decreased as S. obtusifolium seeds absorbed water

An enhanced mill extraction model

An enhanced mill extraction model has been developed to calculate mill performance parameters and to predict the extraction performance of a milling unit. The model takes into account the fibre suspended in juice streams and calculates filling ratio, reabsorption factor, imbibition coefficient, and separation efficiency using more complete definitions than those used in previous extraction models. A mass balance model is used to determine the fibre, brix and moisture mass flows between milling units so that a complete milling train, including the return stream from the juice screen, is modelled. Model solutions are presented to determine the effect of different levels of fibre in juice and efficiency of fibre separation in the juice screen on brix extraction. The model provides more accurate results than earlier models leading to better understanding and improvement of the milling process.

Modelling the flow of cane constituents through the milling process of a raw sugar factory

This thesis reports on an investigation to develop an advanced and comprehensive milling process model of the raw sugar factory. Although the new model can be applied to both, the four-roller and six-roller milling units, it is primarily developed for the six-roller mills which are widely used in the Australian sugar industry. The approach taken was to gain an understanding of the previous milling process simulation model "MILSIM" developed at the University of Queensland nearly four decades ago. Although the MILSIM model was widely adopted in the Australian sugar industry for simulating the milling process it did have some incorrect assumptions. The study aimed to eliminate all the incorrect assumptions of the previous model and develop an advanced model that represents the milling process correctly and tracks the flow of other cane components in the milling process which have not been considered in the previous models. The development of the milling process model was done is three stages. Firstly, an enhanced milling unit extraction model (MILEX) was developed to access the mill performance parameters and predict the extraction performance of the milling process. New definitions for the milling performance parameters were developed and a complete milling train along with the juice screen was modelled. The MILEX model was validated with factory data and the variation in the mill performance parameters was observed and studied. Some case studies were undertaken to study the effect of fibre in juice streams, juice in cush return and imbibition% fibre on extraction performance of the milling process. It was concluded from the study that the empirical relations developed for the mill performance parameters in the MILSIM model were not applicable to the new model. New empirical relations have to be developed before the model is applied with confidence. Secondly, a soluble and insoluble solids model was developed using modelling theory and experimental data to track the flow of sucrose (pol), reducing sugars (glucose and fructose), soluble ash, true fibre and mud solids entering the milling train through the cane supply and their distribution in juice and bagasse streams.. The soluble impurities and mud solids in cane affect the performance of the milling train and further processing of juice and bagasse. New mill performance parameters were developed in the model to track the flow of cane components. The developed model is the first of its kind and provides some additional insight regarding the flow of soluble and insoluble cane components and the factors affecting their distribution in juice and bagasse. The model proved to be a good extension to the MILEX model to study the overall performance of the milling train. Thirdly, the developed models were incorporated in a proprietary software package "SysCAD’ for advanced operational efficiency and for availability in the ‘whole of factory’ model. The MILEX model was developed in SysCAD software to represent a single milling unit. Eventually the entire milling train and the juice screen were developed in SysCAD using series of different controllers and features of the software. The models developed in SysCAD can be run from macro enabled excel file and reports can be generated in excel sheets. The flexibility of the software, ease of use and other advantages are described broadly in the relevant chapter. The MILEX model is developed in static mode and dynamic mode. The application of the dynamic mode of the model is still under progress.

Regulation of dormancy in barley by blue light and after-ripening : effects on abscisic acid and gibberellin metabolism

White light strongly promotes dormancy in freshly harvested cereal grains, whereas dark and after-ripening have the opposite effect. We have analyzed the interaction of light and after-ripening on abscisic acid (ABA) and gibberellin (GA) metabolism genes and dormancy in barley (Hordeum vulgare ‘Betzes’). Analysis of gene expression in imbibed barley grains shows that different ABA metabolism genes are targeted by white light and after-ripening. Of the genes examined, white light promotes the expression of an ABA biosynthetic gene, HvNCED1, in embryos. Consistent with this result, enzyme-linked immunosorbent assays show that dormant grains imbibed under white light have higher embryo ABA content than grains imbibed in the dark. After-ripening has no effect on expression of ABA biosynthesis genes, but promotes expression of an ABA catabolism gene (HvABA8′OH1), a GA biosynthetic gene (HvGA3ox2), and a GA catabolic gene (HvGA2ox3) following imbibition. Blue light mimics the effects of white light on germination, ABA levels, and expression of GA and ABA metabolism genes. Red and far-red light have no effect on germination, ABA levels, or HvNCED1. RNA interference experiments in transgenic barley plants support a role of HvABA8′OH1 in dormancy release. Reduced HvABA8′OH1 expression in transgenic HvABA8′OH1 RNAi grains results in higher levels of ABA and increased dormancy compared to nontransgenic grains.

Modelling milling train performance

This paper describes recent updates to a milling train extraction model used to assess and predict the performance of a milling train. An extension was made to the milling unit model for the bagasse mills to replace the imbibition coefficient with crushing factor and mixing efficiency. New empirical relationships for reabsorption factor, imbibition coefficient, crushing factor, mixing efficiency and purity ratio were developed. The new empirical relationships were tested against factory measurements and previous model predictions. The updated model has been implemented in the SysCAD process modelling software. New additions to the model implementation include: a shredder model to assess or predict cane preparation, mill and shredder drives for power consumption and an updated imbibition control system to add allow water to be added to intermediate mills.

Transcriptional events during early phase of germination of rice embryos

GERMINATION transfers a metabolically inert embryo into an active state of growth and development. The presence of conserved mRNAs has been demonstrated in different species of eggs and seeds1–4. In rice embryos, germination was shown to be independent of the synthesis of RNA up to 18–24 h after the start of imbibition5, although RNA synthesis was detected as early as 9 h after the start of imbibition. In this report, the sequence of the transcriptional events taking place during the early phase of the germination of rice embryos are presented.

Carbon-13 NMR studies of lipid mobilization pattern in germinating groundnut (Arachis hypogaea L.) seeds

The products of lipid mobilization in groundnut (Arachis hypogaea L.) seeds as a function of time immediately after imbibition are monitored by 13C NMR. Different parts of the embryonic axis, namely,the radicle, hypocotyl, and plumule, exhibit characteristic time dependent 13C NMR spectra observed at 24-h intervals after imbibition. The various stages in the transformation of storage lipids present in different parts of the embryonic axis are clearly demonstrated. The transformaton of storage lipids is completed first in the radicle followed by the hypocotyl and finally the plumule. A mechanism of the transformation of the storage lipids is discussed.

Preparation of the layered double hydroxide (LDH) LiAl2(OH)(7)center dot 2H(2)O, by gel to crystallite conversion and a hydrothermal method, and its conversion to lithium aluminates

A layered double hydroxide (LDH) with chemical composition LiAl2(OH)(7) . 2H(2)O was prepared via a wet chemical route of gel to crystallite (G-C) conversion at 80 degrees C involving the reaction of hydrated alumina gel, Al2O3.yH(2)O (80 < y < 120) with LiOH (Li2O/Al2O3 greater than or equal to 0.5) in presence of hydrophilic solvents such as ethanol under refluxing conditions. The hydrothermal synthesis was carried out using the same reactants by heating to less than or equal to 140 degrees C in a Teflon-lined autoclave under autogenerated pressure (less than or equal to 20 MPa). Transmission electron microscopy showed needle-shaped aggregates of size 0.04-0.1 mu m for the gel to crystallite conversion product, whereas the hydrothermal products consisted of individual lamellar crystallites of size 0.2-0.5 mu m with hexagonal morphology. The LDH prepared through the gel to crystallite conversion could be converted into LiAl(OH)(4) . H2O or LiAl(OH)(3)NO3 . H2O by imbibition of LiOH or LiNO3, respectively, under hydrothermal conditions. Thermal decomposition of LDH above 1400 degrees C gave rise to LiAl5O8 accompanied by the evaporation of Li2O. LiAl(OH)(4) . H2O and LiAl(OH)(3)NO3 . H2O decomposed in the temperature range 400-1000 degrees C to alpha- or beta-LiAlO2. The compositional dependence of the product, the intermediate phases formed during the heat treatment and the possible reactions involved are described in detail.

低渗透油藏渗吸法采油的数值模拟

针对渗吸法采油中的毛管力驱动项和流动系数的取值问题，根据地下流体渗流特征，建立了低渗透油藏渗吸法采油数学模型，给出了数值解法．定量分析了渗吸法采油的主要影响因素，通过实例验证，用该方法计算的各项动态指标与矿场实际值符合程度较高．结果表明：基质与裂缝渗透率之比小于O．Ol，油水黏度比小于15，毛管力较大的水湿油层比较适合于渗吸法采油，能够提高水驱采收率2％左右．

番茄种子萌发的高温耐性诱导及其生理效应

番茄（Lycopersicon esculentum Miller）原产于南美西部高原地带，适应原产地赤道附近高地干燥冷凉的气候特点，不耐高温多湿，种子萌发期间对高温非常敏感。本研究以佳粉17番茄种子为材料，试图寻找诱导番茄种子萌发期间高温耐性的方法，并通过研究高温耐性被诱导前后种子内部发生的生理生化变化，探索番茄种子萌发期间不耐高温以及高温耐性诱导的机理。试验结果显示： 25 ℃是种子萌发的最适温度，种子发芽率为97.5%。高温抑制种子的萌发，33 ℃和35 ℃条件下萌发率分别为58.5%和8.5%。 萌发适宜温度预吸胀、低温预吸胀、吸湿-回干预处理可提高番茄种子萌发期间的高温耐性，而水杨酸处理则没有明显效果。种子经25 ℃预吸胀30 h、0 ℃预吸胀10 h、吸湿-回干预处理后在33 ℃条件下的萌发率分别为81.5%、78.0%、90%，在35 ℃下的萌发率分别达到33.5%、42%、48.5%。经以上处理后，种子萌发速率提高，萌发高峰期提前，幼苗生长健壮，根干重增加，活力指数变大。 番茄种子萌发期间遭受高温危害时，电解质渗漏增加，相对电导率升高；脂膜过氧化作用加剧，其产物MDA的含量增加。经萌发适宜温度预吸胀、低温预吸胀、吸湿-回干等方法预处理后，高温伤害减轻，膜的完整性增强，电解质渗漏减缓，膜脂过氧化作用减弱，因而相对电导率降低，MDA含量减少。 高温抑制了抗氧化酶的活性，种子内部SOD、APX、CAT、GR等抗氧化酶活性降低。经萌发适宜温度预吸胀、低温预吸胀、吸湿-回干等方法预处理以后，抗氧化酶活性有不同程度的提高，清除细胞内超氧阴离子自由基的能力增强，因而使过氧化伤害减弱， 适宜温度预吸胀、低温预吸胀、吸湿-回干等预处理方法在保护生物膜的同时，增强抗氧化作用，抑制过氧化伤害，从而提高了番茄种子萌发的高温耐性，这是番茄种子高温耐性提高的生理机制之一。

大豆种子低温吸胀相关基因的分离与蛋白变化的研究

大豆 (Glycine max (L.) Meer.)是人们日常生活中不可缺少的食品，也是一种非常重要的油质、蛋白资源。目前根据大豆种子吸胀阶段对低温敏感性的不同，可将其划分成3种生态型：低温非敏感型、低温敏感型及中间型。对于低温非敏感型的种子来讲，4℃下吸胀24小时对其发芽率影响很小，而敏感型种子萌发率不超过5%。我国属于温带大陆性气候，大豆播种后由于温度波动而造成一部分种子不能萌发，最终导致减产甚至绝产的现象普遍存在。高产是育种工作的主要目标，提高逆境胁迫的适应能力是高产的前提和基础，所以从分子角度研究种子吸胀非常必要，一方面能够挖掘新的基因资源，另一方面为今后育种工作提供必要的理论依据。 本试验以此为立足点，低温吸胀非敏感型大豆品种 (Z22)为材料，利用cDNA-AFLP方法及蛋白质技术分离与低温吸胀相关的基因及蛋白，得到结果如下： 第一，本试验成功的分离出4个受低温诱导的基因，半定量RT-PCR方法进一步验证了这4个基因在种子吸胀24小时内受低温诱导。 第二，利用RACE方法成功的得到2个完整的全长基因，在NCBI数据库中查找后发现其中1个基因为新基因，命名为SCHI基因 (SCHI：Soybean chilling-induced gene)。SCHI全长为390bp，编码分子量大约为14.2KD的蛋白；另外一个基因是已知基因，其同源序列已经在其他的物种中得到分离。由于此基因与核糖体蛋白L34高度同源，所以把把这个基因命名为SOL34 (Soybean L34)。 第三，利用半定量RT-PCR方法对基因表达模型进行分析，结果表明：SCHI在种子低温吸胀18～24小时期间诱导表达量最高，而当种子低温吸胀24小时后转入常温下，其表达量在常温下18小时左右迅速下降；ABA (100μM)、PEG (30%，10000)及NaCl (250mM)能够诱导SCHI的表达，在诱导表达量上，ABA和PEG诱导效果最明显，而NaCl能够微弱的诱导此基因表达；对不同生态型的大豆品种而言，低温吸胀过程中，SCHI在非敏感型种子中的表达量高于敏感型种子，但非敏感型和中间型之间没有差别；另外，SCHI在大豆胚轴中是诱导型表达，在叶片和根尖中则是组成型表达。SOL34的表达在萌发前24小时内被低温诱导，但在不同生态型之间没有差别。SOL34在胚轴和根尖中受低温诱导，在叶片中是组成型表达。 第四，SCHI能够在原核生物中表达出相应蛋白，诱导表达蛋白的分子量在26-29KD，大约为理论值的2倍，说明在大肠杆菌中被表达的蛋白以2聚体形式存在。另外低温试验结果表明SCHI能够提高菌落忍耐短时间-20℃低温的能力。 第五，利用双元表达载体把SCHI转入拟南芥植株，经过低温、干旱和盐胁迫后，转基因植株的成活率均高于野生型植株。超表达SOL34的拟南芥植株降低了对低温的耐性；而抑制拟南芥中L34的表达反而提高了植株对低温的抗性。 第六，本试验利用蛋白质等有关试验检测了大豆种子低温吸胀时蛋白质发生的变化。从吸胀 (4℃和22℃下24h)后的大豆胚轴中成功鉴定出上调蛋白点25个，下调蛋白点15个。其中有参与能量代谢反应 (占10%，例如柠檬酸脱氢酶和苹果酸脱氢酶等)、细胞生长与分裂相关反应 (20%，例如LEA蛋白和种子成熟蛋白PM26)、胁迫反应 (10%，如乙醇脱氢酶)、种子宿命和贮藏蛋白 (20%，大豆球蛋白)等蛋白在此过程中发生了变化，暗示种子萌发前期低温吸胀过程中多种代谢发生变化。细胞生长变缓、能量代谢增强、胁迫代谢蛋白的高表达以及贮藏蛋白降解速度减慢等变化都有利于种子在吸胀过程中度过低温环境，为以后的生长作好准备。

低温吸胀对大豆种子呼吸代谢影响的研究

大豆是重要的油料和蛋白植物。在生产实践中，在播种后达到早苗和齐苗是大豆丰收的前提。种子的吸胀冷害是农业生产的严重问题。吸胀冷害发生在种子开始吸水萌动的萌发初始阶段。吸胀冷害不仅发生在高寒地带和低温冷湿地区，尤其在我国东北地区，造成我国乃至全球大豆不同程度的减产。吸胀冷害的原初作用位点在生物膜上，本实验从呼吸代谢的角度研究吸胀冷害对种子活力的影响，探讨吸胀冷害的机制。 本实验选用由黑龙江省黑河农业科学院提供的对低温中度敏感的黑河13 号大豆种子为材料，分别经22°C、10°C 和4°C 恒温培养箱24 h 后，测定其生理指标，通过透射电镜观察细胞超微结构，利用蛋白质组技术研究低温吸胀与种子呼吸代谢的关系，得到的结果如下： 低温吸胀阻碍胚轴膜系统的修复。通过电解质渗漏率测定发现，4°C 到22°C 温度范围内，提高吸胀温度有助于保持细胞膜的完整性，显著降低吸胀后胚轴电解质渗漏。在低温下吸胀，胚轴活性氧清除酶的活性受到抑制，活性氧含量增加，增强了膜脂过氧化作用，进而导致种子活力下降。 通过透射电子显微镜观察，大豆种子在22°C 吸胀24 h 后，胚轴细胞液泡明显变大，在细胞中所占比例很高，并且细胞内膜系统比较发达，能清晰观察到细胞核，线粒体，质膜，内质网整齐有序的形状。胚轴的细胞含有其它结构正常的细胞器，包括细胞壁，胞间连丝，淀粉粒和油体等。线粒体的外膜、内膜、嵴发育较完善。10°C 和4°C 的吸胀严重损伤了胚轴中细胞器的修复，细胞膜不规则，没有发现内质网和胞间连丝，线粒体的体积较小以及膜系统不发达，尤其是4°C 吸胀的胚轴中细胞器的损伤更加严重，细胞膜系统紊乱。 低温吸胀抑制了线粒体从轻线粒体向重线粒体的修复，以及线粒体的耗氧能力。22°C 吸胀的线粒体的总体耗氧能力较高，电子传递主要是利用复合体I 的电子传递途径。10°C 吸胀的线粒体总体耗氧呼吸较低，且其线粒体的电子传递主要以复合体II 的途径。4°C 吸胀的线粒体的耗氧能力则更低。 将分离得到的线粒体进行的蛋白质组分析，共分离400 多个蛋白点，其中有20 个点有表达差异。经ESI-Q-TOF-MS/MS 鉴定，六个下调的蛋白质分别为ATP 合成酶的亚基 (线粒体的氧化磷酸化)，线粒体延长因子Tu（线粒体基因组转录）， 苹果酸脱氢酶（三羧酸循环），精氨酸酶（尿素循环）和2 个线粒体chaperonin-60 （热稳定蛋白）。这些蛋白在低温吸胀时下调表达，影响了线粒体的正常生理代谢，说明它们在维持线粒体正常代谢中起到了重要的作用。 综上所述，低温吸胀影响了线粒体的结构和生理功能的修复，减少了能量和中间物质供应给种子萌发，造成了种子活力的下降。

化感物质香豆素对苜蓿种子萌发及幼苗初级氮同化的影响

香豆素类物质是苯丙酸内酯（环酯）类化合物，绝大部分高等植物通过次生代谢途径都能合成。研究表明，香豆素类物质是花椒体内最重要的化感物质，系统研究香豆素类物质的作用机理有助于理解和最终解决花椒连作障碍。本文通过研究香豆素对几种植物种子特别是苜蓿种子萌发、苜蓿幼苗初级氮同化的影响，从生理生化角度揭示香豆素的作用方式，为花椒连作障碍的解决和化感作用机制的深入理解提供依据。主要研究结果如下：1. 研究了香豆素对6 种常见作物种子萌发的影响，并对一组数据采用4个不同的指标进行评价，对生物测定化感作用中存在的问题进行了讨论。结果发现1.0mM的香豆素对采用的6 种作物的种子萌发均表现出一定的化感作用，4 个指标的敏感程度依次为S (发芽速度)＞AS(累积发芽速度)＞CRG(发芽指数)＞GT(最终发芽率)。种子萌发实验是化感作用研究中最重要、应用最广泛的生物测定方法之一，应根据不同的研究目的合理采用指标和实验方法。2. 采用培养皿试纸法进行种子萌发试验，研究了香豆素水溶液在苜蓿种子萌发过程中对其吸水、电导率及抗氧化保护酶活性的影响。结果表明，影响苜蓿种子发芽的香豆素浓度阀值为0.3mM。香豆素在1.0mM 的浓度下降低了苜蓿种子吸水阶段Ⅱ的吸水速度，使其外渗物质增多，电导率增大，并显著抑制了超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)的活性，同时种子体内丙二醛（MDA）的含量显著增大。高浓度香豆素破坏了膜的结构、影响了抗氧化保护酶的活性是香豆素降低苜蓿发芽率的原因之一，也可能是影响花椒-苜蓿间作的关键因素之一。3. 不同浓度（0、25 μM、50 μM、0.1 mM、1.0 mM）化感活性物质香豆素对10 日龄苜蓿幼苗初级氮同化的影响的结果表明25 µM～50 µM 的香豆素加快了苜蓿幼苗对硝态氮的吸收。高浓度的香豆素导致苜蓿根系和叶片内可溶性蛋白含量降低、鲜重减小、地下鲜重/地上鲜重（R/S）的比值升高，根系中初级氮同化的关键酶硝酸还原酶（NR）、谷氨酸胺合成酶（GS）、谷氨酸脱氢酶（GDH）的活性降低，叶片中NR、GS 的活性减低、叶绿素含量减少，而GDH 的活性升高。香豆素影响苜蓿幼苗氮代谢和氨同化的关键酶，导致体内养分的缺失是香豆素抑制苜蓿幼苗生长的机理之一。Coumarins are lactones of o-hydroxycinnamic acid, and are allelopathiccompounds that originate in the phenylpropanoid pathway. They are synthesized byalmost all higher plants. According to previous studies, coumarins were mostimportant allelochemicals in Chinese prickly ash. Systematically research of theeffect of coumarin could help to comprehend the continuous cropping impediment.The effects of coumarin on seed germination and primary nitrogen assimilation ofalfalfa were studied. The main results showed that:1. We compared four common germination indices (S, AS, CRG, GT)preciously calculated with the same date. The results showed that, at theconcentration of 1.0 mM, coumarin inhibited seeds germination. Among all indices,the S index was most sensitive, followed by the AS and CRG indices. Andsuggestions on the expression of bioassay results were also provided.2. At concentrations above 0.3 mM, coumarin inhibited seed germination in aconcentration-dependent manner. During seed imbibitionⅡ, coumarin at 1.0 mMsignificantly reduced the activities of superoxide dismutase (SOD), catalase (CAT),peroxidase (POD), while the content of malonyldialdehyde (MDA) in alfalfa seedssignificantly increased. The higher concentration coumarin destroyed structure ofmembrane and influenced activities of antioxidant enzymes, which might be one ofthe reasons that coumarin decreased germination rate of alfalfa, and one of the keyfactors influencing Chinese prickly ash-alfalfa intercropping.3. Alfalfa plants were exposed to different concentration of coumarin (0、25μM、50 μM、0.1 mM、1.0 mM) grown for 10 days on control medium. Coumarin, in the range of 25 μM～50 μM, significantly stimulated the net nitrate uptake.Increasing coumarin concentration led to a decrease of protein contents in theleaves and roots. The root to shoot (R/S) FW ratio was increased by increasingcoumarin concentration. Under high coumarin concentration, the activities of nitratereductase (NR) and glutamine synthetase (GS) were repressed in the roots andleaves. Glutamate dehydrogenase (GDH) was inhibited in the roots, while enhancedin the leaves. Chlorophyll contents in the leaves were also decreased under highcoumain concentration. Coumarin decreased alfalfa growth by (i) nutritionaldeficiencies shown by the decrease of nitrate, (ii) lowered N compound synthesisvia inhibition of nitrate reduction and ammonium assimilation.