Changes in nitrogen compounds in must and wine during fermentation and biological aging by flor yeasts.

Urea, ammonium, and free amino acid contents were quantified in a must from Vitis vinifera cv. Pedro Ximenez grapes and in fermented wine and after a short aging of this wine by Saccharomyces cerevisiae race capensis yeast under variable oxygen availability conditions. The previous compounds were also determined in a wine in which the nitrogen source was depleted by the same race of flor yeast (old wine) and also following the addition of ammonium ion, L-glutamic acid, and L-proline. Under specific conditions such as low oxygen level and the absence of some nutrients, the yeasts release some amino acids including L-threonine, L-tryptophan, L-cysteine, and L-methionine to the medium. These amino acids must originate primarily in a de novo synthesis from ethanol that regenerates NAD(P)+. On the basis of these results, the yeasts may be able to use amino acids not only as nitrogen sources but also as redox agents to balance the oxidation-reduction potential under conditions of restricted oxygen, when electron transport along the respiratory chain may be hindered or limited.     

锰对板栗实生苗生长及生理效应的影响

采用短期培养模拟研究法,在5个Mn2+浓度（0、 0.905、 1.810、 2.715、 3.620 mg/L）处理下,通过测定板栗实生苗木的光合特性、 叶绿素含量、 苗高、 根颚直径、 根系、 生物量与叶片矿质元素等指标,研究了Mn 2+对其生长及生理效应的影响。结果表明, 1）在Mn 2+浓度为0~3.620 mg/L范围内,随Mn2+浓度增大,板栗实生苗净光合速率、 气孔导度、 蒸腾速率、 叶绿素含量、 苗高、 根颚直径、 根重和生物量呈先增加后降低的趋势,其中以Mn 2+浓度1.810和2.715 mg/L处理的效果最好,且两处理间差异不显著（P0.05）; 2）与CK相比,Mn2+增加了苗木对锰的吸收,但抑制了对钙、 铁、 铜的吸收,随Mn2+浓度增大,叶片磷、 硼含量呈先升高后降低趋势,钾含量变化趋势相反; 3）相关分析显示,叶片锰含量与钙、 铁、 铜含量呈显著性负相关（P0.05）,与磷、 钾、 硼含量的相关性均不显著（P0.05）。综上,当Mn2+浓度为1.810和2.715 mg/L时均能显著促进板栗苗木的光合及生长; 但Mn2+浓度不宜过高,大于2.715 mg/L则抑制其生长,不利于矿质元素的均衡吸收。     

土壤质量对植物光合生理生态功能的影响研究进展

土壤质量是土壤肥力质量、环境质量和健康质量的综合体现。阐述了国内外土壤养分与水分、土壤盐分与微量元素对植物光合生理生态功能的影响研究进展     

水分胁迫对刺五加幼苗光合生理特性的影响

 通过对刺五加（Acanthopanax Senticosus）幼苗的盆栽实验,模拟4个土壤水分梯度（对照、轻度水分胁迫、中度水分胁迫和重度水分胁迫）下,刺五加幼苗的光合色素、光合作用以及脯氨酸和丙二醛含量的变化特性。结果表明:光合色素含量随水分胁迫程度的加强呈下降的趋势,中度和重度水分胁迫组的光合色素含量较低,均显著低于对照组,而轻度水分胁迫组的光合色素含量与对照组差异不明显,且一直保持很高水平。各组的叶绿素与类胡萝卜素含量比值在3.02～3.65之间波动。在轻度的水分胁迫环境下,其净光合速率未受到显著影响,保持与对照组一致的较高水平,其蒸腾速率较低,比对照组下降27.25%,而水分利用效率比对照组增加26.97%。在中度水分胁迫环境下,刺五加幼苗表现出了较低的净光合速率和蒸腾速率以及较高的水分利用效率,与对照组相比,净光合速率下降29.46%,蒸腾速率下降50.67%,水分利用效率升高33.70%;重度的水分胁迫下的净光合速率和蒸腾速率均处于最低水平,但此时水分利用效率却最大,高出对照77.51%。在整个实验期,叶片脯氨酸和丙二醛含量随着干旱胁迫强度的增加和胁迫时间的延长而持续上升。研究表明,刺五加幼苗具有一定的抗旱能力,但不适应相对干旱的土壤水分环境。研究结论为人工栽培刺五加提供了科学依据。     

微孔曝气流量与曝气管长度对水体增氧性能的影响

为了探究曝气流量与曝气管长度对增氧性能的影响,在不同曝气流量、不同曝气管长度条件下进行了室内水体底部微孔曝气增氧试验。分析了曝气流量与曝气管长度对氧体积传质系数、增氧量和氧利用率的影响。研究结果表明,当曝气流量为0.27~0.55 m3/s、曝气管长为0.9~1.5 m时,所对应的氧体积传质系数在0.63~1.1 h-1变化,增氧量在6.8~12.9 g/h变化,氧利用率在6.87%~9.28%变化,且在一定的曝气管长度下,氧体积传质系数、增氧量均与曝气流量成正比,而氧利用率则与其成反比关系;在一定的曝气流量下,曝气管长度对氧体积传质系数产生的影响表现为先高后低再高的趋势;氧体积传质系数与修正的饱和溶解氧浓度是否作为增氧量的主要影响因子取决于曝气管长度;曝气流量对氧利用率较曝气管长度更为敏感。研究还发现,微孔曝气系统中存在着最优曝气管长度,使得增氧性能最佳,并建立了最优曝气管长度与曝气流量、水深、输入压力、最优初始气泡直径的相关关系式,为低碳经济下微孔曝气系统的设计和运行提供了理论依据。     

Influence of nano-iron oxide and zinc sulfate on physiological characteristics of peppermint

To evaluate the impact of nano-iron oxide and zinc sulfate fertilizers on peppermint in field conditions, a factorial split experiment with two micro-nutrient fertilizers [Zinc (Zn) and Iron (Fe)] in RCBD with three replicates was conducted at University of Tehran, during 2014 and 2015. Fe at four levels (0, 0.25, 0.5, and 0.75 g L-1) and Zn at three levels (0, 2.5, and 5 g L-1) were applied. Fe and Zn fertilizer application significantly improved photosynthetic pigments, mineral nutrient content, essential oil concentration, and dry matter yield in peppermint. The highest iron content (1578.00 mg kg^?1) was achieved when 5 g L^?1 of Zn was applied along with 0.75 g L^?1 Fe. According to our results, the application of 2.5 g L^?1 of Zn plus 0.5 g L^?1 Fe fertilizers could be recommended to achieve the highest plant dry matter and essential oil yield.     

Influence of AM fungi on the growth and physiological status of Erythrina variegata Linn. grown under different water stress conditions

The present study investigated the effects of arbuscular mycorrhizal (AM) fungus, Glomus mosseae on the growth and physiology state of Erythrina variegata Linn, grown in sandy loam soil with four water stress levels viz. ?0.06 MPa (well watered/control), ?1.20 MPa (mild), ?2.20 MPa (moderate) and ?3.20 MPa (severe) in a completely randomized design. Plants were harvested after 90 days (60 days after stress induction) of growth. Growth parameters (root &, shoot, dry weight and, leaf area); physiological parameters (chlorophyll content, carotenoids, soluble starch, sugar, protein and proline in shoots); and microbiological parameter (percentage of mycorrhizal infection) were determined. AM fungal plants had significantly higher plant biomass, higher chlorophyll content (chlorophyll a and b), carotenoids and protein content in shoots than non-AM-plants. The AM-inoculation in stressed plants significantly declined the soluble sugar and starch in shoots. Moreover, AM-inoculation also reduced the proline accumulation in shoots and the reduction was significant when plants were severely stressed (?3.2 MPa). Mycorrhizal colonization in roots of E. variegata depressed significantly due to increased water stress. However, the AM colonization did not decline below 11% and enabled the plants to maintain osmotic adjustments and enhanced the plants tolerance against water stress.     

多级跌水充氧式沟渠连通生态塘污水处理效果及优化模拟试验

针对农村污水流量小浓度高、排放不均匀及降雨冲击等特点,设计多级跌水充氧式沟渠连通生态塘组合工艺,进行水力负荷、运行方式、水量波动、降雨冲击等影响因素及参数优化试验。结果表明:随着水力负荷的增大,污染物的去除率逐渐降低;间歇运行的处理效果优于连续运行;水量的波动导致污染物的去除率也随之变化,其中化学需氧量和氨氮的去除率最大降幅接近20%;总氮去除率的降幅最大,约25%;总磷的去除率最大降幅最小,约15%左右;当降雨规模变大时,组合工艺对各污染物去除率分别从53.95%、52.44%、49.92%、71.64%下降到40.94%、43.75%、34.93%、53.84%。采取地表径流截流措施后,组合工艺对各污染物的去除效果有所改善,去除率的上升与截流倍数的增加近似呈现线性关系,当降雨为暴雨,采取截流倍数为5时,出水水质仍能达到城镇污水处理厂污染物排放标准(GB18918-2002)一级排放标准,对降雨期间农村污水的污染去除具有重要意义。     

盐胁迫对诱变小麦种子萌发及幼苗生理特性的影响

本研究以化学诱变获得的小麦突变体为材料,研究了盐胁迫对小麦发芽及幼苗生长的影响。结果表明,随着NaCl浓度(0、100 mmol.L 1、200 mmol.L 1、300 mmol.L 1、400 mmol.L 1)的增加,小麦的发芽率、发芽指数、活力指数、芽长、根长、芽鲜重和干重、根鲜重和干重均呈下降趋势,300 mmol.L 1NaCl为4种小麦(3个突变体、1个对照CAO811CK)发芽能力的临界盐浓度,其中突变体CAO8113K优于其他小麦材料。在300 mmol.L 1NaCl胁迫下,随着时间延长(12 h、24 h、48 h、96 h、192 h),4种小麦材料幼苗可溶性蛋白含量、丙二醛(MDA)含量逐渐增加,超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性呈上升趋势。采用模糊数学隶属函数法对可溶性蛋白、MDA、SOD、POD、CAT 5项生理指标进行综合评价,4种小麦材料耐盐潜力由强到弱依次为CAO8113K>CAO811CK>CAO8114K>CAO8112K,CAO8113K突变体小麦材料表现出较强抗盐性,与发芽指标检测结果基本一致。     

钾肥对杂交水稻养分积累以及生理效率的影响

在浙江省金华市进行连续4年水稻钾肥田间试验,以研究钾肥对杂交水稻氮磷钾养分吸收和利用效率的影响。结果表明,钾肥可促进氮磷养分从水稻的茎叶部位向穗输送,增加水稻产量。同不施钾处理比较,施钾处理杂交稻氮的平均吸收总量增加7.1～9.3kg/hm2,磷增加0.9～1.1kg/hm2,钾增加38.3～56.6kg/hm2;氮和磷养分的利用效率无显著提高,而钾素的利用效率明显降低26.3%～28.9%。在养分的吸收和利用效率方面,杂交稻较常规稻表现出明显的生理优势。分析土壤交换性钾和缓效钾含量的年动态变化得出,杂交稻较常规稻消耗土壤中更多的缓效钾,施钾处理下的测试土壤速效钾含量逐年下降,而土壤缓效钾含量却有逐年上升的趋势。     

移动式太阳能增氧机的增氧性能评价

为改善池塘养殖环境,设计了一种移动式太阳能增氧机,由光伏供电装置和水面行走装置搭载涌浪机而成,能在水面沿钢丝绳移动并利用涌浪机的波浪增氧和水层交换作用,大范围扰动水体并为池塘增氧。该研究的目的是通过机械增氧效率检测、提水能力测定和池塘增氧能力测定3个试验,评估太阳能增氧机的机械增氧性能、水层交换性能和实际应用效果,以期全面了解移动增氧机增氧能力。结果表明,该移动式太阳能增氧机最大机械增氧能力为1.24 kg/h,动力效率2.59 kg/(k W·h);最大提水能力1 254.4 m3/h,提水动力效率2 613.3 m3/(k W·h);并在晴好天气白天(09:00—19:00),在对照组底层溶氧为3.1~3.8 mg/L时,大幅度提升池塘底层溶氧水平,最高时达7.8 mg/L,维持池塘上下溶氧均匀度72%~84%,极大改善了底层溶氧环境。数据表明移动式太阳能增氧机具有良好的机械增氧和水层交换性能,因而能有效改善池塘底层溶氧环境,提高上下水体溶氧均匀度。该研究结果可为太阳能增氧机的进一步推广应用提供数据支撑。     

Millimetre scale aeration of the rhizosphere and drilosphere

Soil aeration is a critical factor for oxygen-limited subsoil processes, as transport by diffusion and advection is restricted by the long distance to the free atmosphere. Oxygen transport into the soil matrix is highly dependent on its connectivity to larger pore channels like earthworm and root colonised biopores. Here we hypothesize that the soil matrix around biopores represents different connectivity depending on biopore genesis and actual coloniser. We analysed the soil pore system of undisturbed soil core samples around biopores generated or colonised by roots and earthworms and compared them with the pore system of soil, not in the immediacy of a biopore. Oxygen partial pressure profiles and gas relative diffusion was measured in the rhizosphere and drilosphere from the biopore wall into the bulk soil with microelectrodes. The measurements were linked with structural features such as porosity and connectivity obtained from X-ray tomography and image analysis. Aeration was enhanced in the soil matrix surrounding biopores in comparison to the bulk soil, shown by higher oxygen concentrations and higher relative diffusion coefficients. Biopores colonised by roots presented more connected lateral pores than earthworm colonised ones, which resulted in enhanced aeration of the rhizosphere compared to the drilosphere. This has influenced biotic processes (microbial turnover/mineralization or root respiration) at biopore interfaces and highlights the importance of microstructural features for soil processes and their dependency on the biopore's coloniser.     

通气对石油污染土壤生物修复的影响

为了探讨石油污染土壤的生物修复的有效方法,本研究就通气对石油污染土壤生物降解的影响,在自制反应器中进行了为期50天的堆腐试验。结果表明,通气可为石油烃污染土壤中的微生物提供充足的电子受体,可保持土壤pH稳定,从而促进了微生物的生物活性,强化了它们对石油污染物的氧化降解作用。通过在反应器中,调控通气量使污染土壤中石油烃的降解率进一步提高,为石油污染土壤生物修复技术的应用奠定了科学基础。     

Influence of natural and synthetic humic substances on the activity of urease

The activity of a purified urease, obtained from Bacillus pasteurii, was inhibited by humic and fulvic acids obtained from an agricultural soil. Enzyme kinetic studies showed that the humic substances affected the affinity of the enzyme for its substrate (K_m) and the maximum velocity of the reaction (V_max). The V_max was inhibited to the same extent by both humic (HA) and fulvic (FA) acids, the precise effect depending on the pH and concentration of humic substance. At pH 4.0, HA concentrations of 25 pg cm^?3 and 10 μg cm^?3 inhibited the V_max by 38.5% and 20% respectively. HA and FA had similar effects on the K_m but in this case the lowering of the affinity of the enzyme for its substrate was not concentration dependent in the range 0–25 μg cm^?3 of humic substance. Typically, the affinity was decreased from a K_M of 50 mM in the control to 67 mM in the presence of HA and FA. The effects were not due primarily to the ash or N contents of the humic substances because de-ashed humic acid and synthetic model humic (made from catechol, guaiacol, pyrogallol, resorcinol and protocatechuic acid) and fulvic acid (made from polymaleic acid), containing virtually no ash or N, were equally as effective. The effect was not related to the phenolic monomers which, before polymerization, had no effect on urease activity.     

Systematic studies on structure and physiological activity of cyclic alpha-keto enamines, a novel class of "cooling" compounds.

3-Methyl- and 5-methyl-2-(1-pyrrolidinyl)-2-cyclopenten-1-one were recently identified as intense cooling compounds in roasted dark malt. To gain more insights into the molecular requirements of these compounds for imparting a cooling sensation, 26 cyclic alpha-keto enamine derivatives were synthesized, and their physiological cooling activities were evaluated. Any modification of the amino moiety, the carbocyclic ring size, or incorporation of additional methyl groups led to a significant increase of the cooling threshold. Insertion of an oxygen atom into the 2-cyclopenten-1-one ring, however, increased the cooling activity, e.g., the cooling threshold of the 5-methyl-4-(1-pyrrolidinyl)-3(2H)-furanone was found to be 16-fold below the threshold concentration determined for the 3-methyl-2-(1-pyrrolidinyl)-2-cyclopenten-1-one. Shifting the oxygen atom from the 4- into the 5-position of the cyclopentenone ring resulted in a even more drastic increase in cooling activity, e.g., the 4-methyl-3-(1-pyrrolidinyl)-2(5H)-furanone exhibited the strongest cooling effect at the low oral threshold concentration of 0.02-0.06 mmol/L, which is 35-fold below the value determined for (-)-menthol. In contrast to the minty smelling (-)-menthol, most of the alpha-keto enamines were found to be virtually odorless but impart a sensation of "cooling" to the oral cavity as well as to the skin, thus illustrating that there is no physiological link between cooling activity and mint-like odors.     

干旱胁迫下丛枝菌根真菌对玉米生理生化特性的影响

在土壤有效磷含量较高的条件下,研究了接种丛枝菌根真菌（arbuscular mycorrhizal fungus, AMF）对不同水分处理梯度（田间最大持水量的70%、 45%和20%）条件下玉米生长和抗旱性的影响。结果表明,在三种不同水分处理条件下,接种AMF显著提高了玉米植株地上部的生物量,且对玉米地上部、 地下部全磷含量有显著提高作用。水分胁迫显著降低了玉米叶片水势,增加了玉米叶片脯氨酸、 丙二醛、 过氧化物酶和过氧化氢酶含量,而不同水分梯度条件下接种AMF均显著提高了植株叶片水势,降低了脯氨酸含量,提高了叶片保护酶（过氧化物酶和过氧化氢酶）活性从而减少丙二醛的积累,减轻植物叶片膜脂过氧化的伤害。由此说明,接种AMF在土壤有效磷含量较高的条件下能够与玉米根系形成良好的共生关系,提高玉米的抗旱性。     

Influence of potassium nutrition on norflurazon activity in wheat

Wheat (Triticum aestivum L. cv Stacy) was grown hydroponically and 7‐day old seedlings were exposed to K⁺ (6, 12, 24, or 48mM) and/or norflurazon[4‐chloro‐5‐(methylamino)‐2‐(3‐(trifluoromethyl)phenyl)‐3(2H)‐pyrdazinone] (0, 0.05, 0.10, 0.20, 0.41, or 0.82 μM) for 14 days. Carotenoid content was decreased by high K⁺ nutrition (12–48 mM), but norflurazon‐induced inhibition of carotenogenesis was not observed at high K⁺ nutrition. Phytoene desaturation product concentrations were influenced by K⁺ nutrition.     

Examining N-limited soil microbial activity using community-level physiological profiling based on O2 consumption

Nitrogen-limited soil microbial activity has important implications for soil carbon storage and nutrient availability, but previous methods for assessing resource limitation have been restricted, due to enrichment criteria (i.e., long incubation periods, high substrate amendments) and/or logistical constraints (e.g. use of radioisotopes). A microtiter-based assay of basal and substrate induced soil respiration based on O₂ consumption may be a rapid, ecologically relevant means of assessing N limitation. The present study evaluated this approach by examining 1) the extent and duration of N limitation on soil respiratory activity following different levels of N fertilization in the field, and 2) the relationship between N-limited activities and growth under the assay conditions. Fertilization rate and the time since fertilization had significant impacts on the degree of N limitation of soil microbial activity. The highest fertilization rate showed the earliest and most persistent reduction in N limitation, as would be predicted from the higher concentration of extractable inorganic soil N observed with this treatment. Bacterial growth under the assay conditions, as estimated by quantitative-PCR of 16S rRNA genes, was less than twofold in soils demonstrating a rapid respiratory response (i.e. peak within 6–8 h of initiating incubation) to up to fourfold in soils demonstrating a slower respiratory response (i.e., peak response after ∼14 h of incubation). Increased respiratory response with N amendment was usually associated with increased cell growth, although for rapidly responding soils some C sources showed N-limited use without growth. This was likely due to exhaustion of the relatively low levels of available C amendment before growth was detected. The method appears useful for assessing N-limited microbial growth, and it may be effective as a rapid indicator of bioavailable soil N. It may also be a tool to evaluate the complexity of N limitation among various metabolic pathways found in soil microbial communities, particularly if linked to dynamics in community structure and gene activation.     

微孔扩散器形状对曝气增氧性能影响的试验

为了探究不同形状(直线型、C型、S型和圆盘型)的微孔曝气扩散器对增氧性能的影响,在3个水深和5个曝气流量下进行了一系列的室内曝气增氧试验.结果表明:相同水深和流量下,直线型的氧体积传质系数、充氧能力、动力效率和氧利用率均最大,例如在0.7 rn水深时4个技术指标的范围值分别为0.853～1.762 h-1、8.701～17.432 g/h、4.146～6.869 kg/(kW·h)、3.257％～4.912％;而S型是最低的,其范围值分别为0.798～1.504 h-1、6.850～12.627 g/h、2.630～4.444 kg/(kW·h)、3.823％～2.339％;其次是C型和圆盘型微孔曝气扩散器,其他水深试验条件下也得到了类似的规律.由此说明直线型的增氧效果最好.为了仅探究扩散器形状对增氧性能的影响,在试验水池表面铺设薄膜阻隔了空气-自由水表面氧传质后,4种扩散器的氧体积传质系数均下降,最大的下降率分别为12.29％、8.73％、12.26％和6.74％,空气-自由水表面氧传质对不同形状的扩散器的影响程度不同.但下降后的氧体积传质系数值最高的仍是直线型,其次是C型和圆盘型,S型仍然最低;直线型、C型、圆盘型、S型在0.7 m水深下分别为1.693、1.470、1.438和1.227 h-1,在其他工况下也得到了类似的规律.因此,增氧性能最好的是直线型微孔曝气扩散器.此研究结果可为微孔曝气技术的绿色环保应用以及实际工程中对微孔扩散器形状的选取提供一定的参考价值.