关中地区''陕253''品质与氮、磷、钾配比间关系的研究

选用强筋小麦品种‘陕253’,在关中东、西和中部采取不同的氮(N)、磷(P)、钾(K)肥配比处理,用GGE Bi-plot叠图软件分析肥料配比对不同地区籽粒品质性状的效应。研究结果表明:不同N、P、K配比对强筋小麦品质性状的效应与生态区有关。关中西部蛋白质含量、容重、硬度、稳定时间之间呈显著正相关,蛋白质含量、容重和硬度的最优N、P、K配比是N 135 kg/hm2、P2O5225 kg/hm2、K2O 120 kg/hm2,降落值、出粉率、湿面筋含量和稳定时间是N 225 kg/hm2、P2O5225 kg/hm2、K2O 120 kg/hm2;关中中部蛋白质含量、稳定时间、沉淀值、容重之间呈显著正相关,其最优N、P、K配比为N 225 kg/hm2、P2O5225 kg/hm2、K2O 120 kg/hm2,降落值和吸水率最优N、P、K配比为N 135 kg/hm2、P2O5225 kg/hm2、K2O 180 kg/hm2;关中东部籽粒蛋白质含量与吸水率之间显著正相关,其最优N、P、K配比为N 225 kg/hm2、P2O5225 kg/hm2、K2O 180 kg/hm2,湿面筋含量、降落值、沉淀值、容重、出粉率和硬度间表现极限著的正相关关系,最优N、P、K配比是N 135 kg/hm2、P2O5120 kg/hm2、K2O 120 kg/hm2。     

不同施氮处理玉米根茬在土壤中矿化分解特性

以黄土高原南部地区7a定位试验不同氮肥处理玉米根茬为研究对象,通过室内培养试验研究了施氮量分别为0、120和240 kg N/hm2处理玉米根茬(分别用R0、R120、R240表示)在15-20 cm和45-50 cm土层土壤中有机碳矿化及其对土壤微生物量碳、可溶性有机碳和矿质态氮含量的影响.结果表明,不同处理玉米根茬C/N为R0＞R240 ＞R120.培养条件下,R120和R240根茬的碳矿化速率高于R0根茬,R120与R240根茬之间差异不显著.不同处理根茬C/N与其培养过程中碳素累积表观矿化量呈极显著负相关关系.3种施氮量处理的玉米根茬在培养过程中有机碳矿化率、潜在碳矿化量、土壤微生物量碳、可溶性有机碳含量均为添加R120根茬的处理最高,R240次之,R0最低.添加R120和R240根茬显著提高了培养起始时土壤矿质态氮含量.R0、R120和R240根茬在15-20 cm土层土壤中的碳矿化率分别比其在45-50 cm土层土壤中高51.70％、26.41％和27.84％.在评价根茬还田对农田生态系统碳、氮等养分循环的作用时,应同时考虑施肥对根茬分解和转化的影响.     

间作对氮调控玉米光合速率和光合氮利用效率的影响

研究间作后作物光合碳同化和光合氮利用效率(PNUE)对氮投入的响应, 对阐释间作产量优势的氮调控效应, 指导间作氮肥管理有重要意义。本研究设置玉米(Zea mays)单作、玉米间作两种种植模式的4个氮水平(N0, 0 kg·hm ^-2; N1, 125 kg·hm ^-2; N2, 250 kg·hm ^-2; N3, 375 kg·hm ^-2), 分析间作与施氮量对玉米叶片特征、光合参数、PNUE和产量的影响。结果表明: 与单作相比, 间作显著增加玉米叶片的叶干质量和比叶质量; 各施氮水平(除N3)下, 间作中靠近马铃薯(Solanum tuberosum)侧的玉米叶面积均显著高于单作玉米。单间作对比发现, 间作提高了玉米光饱和点和暗呼吸速率。单作、间作靠玉米侧(I-M)、间作靠马铃薯侧(I-P)的玉米PNUE均随施氮量增加而降低, 降幅以I-P最大; 施氮量低于250 kg·hm ^-2时, 相同施氮量下的玉米PNUE和净光合速率(P_n)均以I-P最高, I-M和单作次之。间作显著提高了玉米产量(土地当量比>1)。该研究中当施氮量≤250 kg·hm ^-2时, 间作I-P的玉米叶片P_n和PNUE显著提高可能是间作玉米产量提高的重要原因。     

Effects of intercropping on photosynthetic rate and net photosynthetic nitrogen use efficiency of maize under nitrogen addition

研究间作后作物光合碳同化和光合氮利用效率(PNUE)对氮投入的响应, 对阐释间作产量优势的氮调控效应, 指导间作氮肥管理有重要意义。本研究设置玉米(Zea mays)单作、玉米间作两种种植模式的4个氮水平(N0, 0 kg·hm ^-2; N1, 125 kg·hm ^-2; N2, 250 kg·hm ^-2; N3, 375 kg·hm ^-2), 分析间作与施氮量对玉米叶片特征、光合参数、PNUE和产量的影响。结果表明: 与单作相比, 间作显著增加玉米叶片的叶干质量和比叶质量; 各施氮水平(除N3)下, 间作中靠近马铃薯(Solanum tuberosum)侧的玉米叶面积均显著高于单作玉米。单间作对比发现, 间作提高了玉米光饱和点和暗呼吸速率。单作、间作靠玉米侧(I-M)、间作靠马铃薯侧(I-P)的玉米PNUE均随施氮量增加而降低, 降幅以I-P最大; 施氮量低于250 kg·hm ^-2时, 相同施氮量下的玉米PNUE和净光合速率(P_n)均以I-P最高, I-M和单作次之。间作显著提高了玉米产量(土地当量比>1)。该研究中当施氮量≤250 kg·hm ^-2时, 间作I-P的玉米叶片P_n和PNUE显著提高可能是间作玉米产量提高的重要原因。     

广西典型红壤旱地施用钙镁磷肥对玉米产量及其镉累积的影响

在广西典型类型红壤旱地布置玉米磷肥施用量的田间试验,研究不同钙镁磷肥施用量(磷肥Cd含量为0.0651 mg/kg)对玉米产量及地上部Cd累积的影响。结果表明,与不施磷肥处理(CK)相比,施磷肥可分别显著提高春、秋玉米籽粒产量8.2%—13.1%和13.7%—20.0%。高磷(600 kg P2O5/hm2)处理的春玉米秸秆产量比CK显著提高11.4%;施磷处理春、秋玉米秸秆Cd含量分别下降2.7%—45.8%和11.0%—43.6%;而籽粒Cd含量分别下降13.0%—40.6%和9.9%—31.5%,且秸秆和籽粒的Cd含量及累积量均随施磷量的增加而逐渐降低,其中以高磷处理最为显著。玉米秸秆及籽粒Cd累积量在高磷处理下(600 kg P2O5/hm2)分别比低磷处理(75—300 kg P2O5/hm2)降低13.6%—41.5%和8.8%—29.3%。相关分析表明,玉米Cd含量与土壤pH呈显著负相关,与土壤有效Cd含量呈显著正相关。施磷提高土壤pH,而降低土壤有效Cd含量。高量磷肥施用降低土壤Cd的有效性进而降低玉米对Cd的吸收累积。     

不同氮肥喷涂吡啶对夏玉米田氮素利用及土壤N2O排放的影响

为减少土壤N₂O排放,提高作物氮素利用,采用田间试验法研究了不同氮肥用量喷涂一定比例的吡啶(0、180、270、360 kg N·hm^-2)对夏玉米生育期内土壤N₂O排放和氮素表观损失、籽粒产量及氮素利用的影响.结果表明:不同氮肥用量下喷涂吡啶的土壤N₂O排放主要集中在播种-苗期和拔节-抽雄期,基肥和追肥后均会出现显著的土壤N₂O排放通量高峰.随氮肥用量增加,玉米产量不断增加,但270和360 kg N·hm^-2间无显著差异,2种施氮量下的玉米分别净增收5209和5426元·hm^-2.与不施氮肥比,各施氮处理下的玉米籽粒吸氮量提高幅度为109.6%～134.1%.各处理间的氮肥农学效率和氮肥利用率均以氮肥喷涂吡啶270 kg N·hm^-2较大,而土壤氮素表观损失较小.氮肥喷涂吡啶在270 kg N·hm^-2时玉米增产增收,氮肥利用效率较高,土壤N₂O排放和氮素表观损失较少,是一种较为合理的氮肥调控施用技术.     

不同氮肥喷涂吡啶对夏玉米田氮素利用及土壤N2O排放的影响

为减少土壤N₂O排放,提高作物氮素利用,采用田间试验法研究了不同氮肥用量喷涂一定比例的吡啶(0、180、270、360 kg N·hm^-2)对夏玉米生育期内土壤N₂O排放和氮素表观损失、籽粒产量及氮素利用的影响.结果表明:不同氮肥用量下喷涂吡啶的土壤N₂O排放主要集中在播种-苗期和拔节-抽雄期,基肥和追肥后均会出现显著的土壤N₂O排放通量高峰.随氮肥用量增加,玉米产量不断增加,但270和360 kg N·hm^-2间无显著差异,2种施氮量下的玉米分别净增收5209和5426元·hm^-2.与不施氮肥比,各施氮处理下的玉米籽粒吸氮量提高幅度为109.6%～134.1%.各处理间的氮肥农学效率和氮肥利用率均以氮肥喷涂吡啶270 kg N·hm^-2较大,而土壤氮素表观损失较小.氮肥喷涂吡啶在270 kg N·hm^-2时玉米增产增收,氮肥利用效率较高,土壤N₂O排放和氮素表观损失较少,是一种较为合理的氮肥调控施用技术.     

水氮耦合对冬小麦氮肥吸收及土壤硝态氮残留淋溶的影响

在高肥力条件下,大田试验采用裂区设计,主区为不同灌水频次(0～3次),裂区为不同施氮量(0～240 kg/hm2),结合15N微区示踪技术,研究了水氮耦合对冬小麦氮肥的吸收利用及生育后期土壤硝态氮累积迁移的影响.结果表明,在一定氮肥水平下,不灌水处理的氮肥利用率高于各灌水处理,各灌水处理的氮肥利用率随灌水次数增加呈上升趋势;增加灌水次数,氮肥耕层残留量和残留率显著降低,氮肥损失量和损失率则明显增加.在一定的灌溉水平上,随施氮量(0～240 kg/hm2)增加,植株总吸氮量、氮肥吸收量、氮肥耕层残留量、氮肥损失量以及损失率均呈上升趋势,而氮肥利用率和耕层残留率呈下降趋势.氮肥水平一定时,在灌0至灌2水范围内,籽粒产量随灌水次数增加呈上升趋势,灌3水处理中施氮处理(N168、N240)的籽粒产量较灌2水处理显著降低;灌水生产效率随灌水次数增加显著下降.在一定灌溉水平上,施氮量由168 kg/hm2增至240 kg/hm2,氮素收获指数和氮肥生产效率显著降低,各灌水处理的生物产量、籽粒产量和籽粒蛋白质含量均无显著变化,不灌水处理的生物产量、籽粒产量显著降低.灌水促进了施氮处理(N168,N240)中土壤硝态氮向下迁移,从开花到收获0～100 cm土层中部分硝态氮迁移到了100～200 cm土层.灌水次数是导致收获期0～100 cm土层残留NO-3-N累积量变化的主导因素;水氮互作效应是决定收获期100～200 cm土层残留NO-3-N累积量变化的主导因素,且灌水效应大于施氮效应.     

陕西关中小麦-玉米轮作区协调作物产量和环境效应的农田适宜氮肥用量

为了确定陕西关中小麦-玉米轮作区兼顾作物产量和环境效应的农田适宜氮肥用量,通过玉米-小麦-玉米连续3季田间试验研究了作物产量、氮肥利用效率、氮肥表观损失和土壤氮素平衡等对施氮量的响应。结果表明,随着氮肥用量的增加,不同年份作物产量和3季作物累计产量均表现为先增加后降低的趋势,而累计氮肥农学效率、氮肥表观利用率、氮肥吸收效率和氮肥偏生产力均表现为显著的降低趋势。土壤氮素平衡结果表明,随着施氮量的增加,低量施氮时(小麦施N150 kg/hm2,玉米施N180 kg/hm2),氮肥残留显著增加,表观损失和损失率变化不明显,而高量施氮时(小麦施N150 kg/hm2,玉米施N180 kg/hm2),氮肥残留变化不明显,表观损失和损失率却显著增加。回归和相关分析显示,矿质氮在土壤较深层次(100—200cm土层)大量累积是氮肥表观损失的重要途径之一。小麦施N 150 kg/hm2、玉米施N 180 kg/hm2时,作物即可获得相对较高的产量和氮肥利用率,且能保持作物收获前后土壤无机氮库的基本稳定,同时也可将氮肥表观损失降至较低水平。     

氮肥施用量对设施番茄氮素利用及土壤NO3--N累积的影响

在宁夏引黄灌区滴灌条件下,以温棚番茄为研究对象,采用田间试验与室内分析的方法,研究不同施氮量对番茄产量、氮素利用率及土壤NO3--N残留的影响,并对土壤-番茄体系的氮平衡进行了表观评估。试验结果表明:2004年秋冬茬番茄,施用氮肥显著增加了当茬番茄果实、植株产量(增产幅度19.9%～29.6%)及地上部总吸氮量(204～232.6kg/hm2)。2005年冬春茬番茄,与空白处理产量相比(106kg/hm2)只有N200处理的果实增产达显著水平(120kg/hm2)。两季番茄的氮肥利用率都随氮肥施用量的增加而明显降低(3.3%～10.9%)。2004年秋冬茬番茄收获后,表层0～30cm的NO3--N大量累积(200～650kg/hm2),其累积量随施氮量增加呈增加的趋势,经过2005年冬春茬番茄种植后,上茬0～30cm土层NO3--N向下有淋失的趋势,淋失层次主要在90cm以上的土体(250～380kg/hm2)。综合考虑番茄果实产量、氮肥利用率及土壤NO3--N残留等因素,秋冬茬番茄推荐氮肥用量在100～200kg/hm2和适量的磷钾肥配施为当茬氮肥优化管理处理。而冬春茬番茄氮肥推荐在200～400kg/hm2范围可以满足当茬番茄对氮肥的需求。     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.     

The effects of glutamine of the maintenance of embryogenic cultures of Cryptomeria japonica

Summary Embryogenic tissues of sugi (Cryptomeria japonica) were induced on a modified Campbell and Durzan (CD) medium containing 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 600 mg l⁻¹ glutamine, and subcultured in the medium of the same composition for over 1 yr. This resulted in a mixed culture of embryogenic and non-embryogenic cells. When embryogenic cells were isolated and cultured independently, their capacity to form embryogenic aggregates was lost. Thus, the non-embryogenic cells present within a mixed culture system were essential to the formation of embryogenic aggregates. When embryogenic tissues were isolated and cultured independently on a high glutamine-containing (2400 mg l⁻¹) medium, dry weights and endogenous levels of glutamine increased, and the tissue could generate a large number of embryogenic aggregates. Amino acid analysis of embryogenic and non-embryogenic cells from the maintenance culture indicated a higher level of glutamine was present in the latter. The high endogenous level of glutamine in the non-embryogenic portion of mixed cell masses may be the supplier of glutamine for maintaining the embryogenic property of the tissues.