施氮量和花后土壤含水量对优质强筋小麦产量和品质的影响

在防雨池栽条件下,研究了施氮量和花后土壤含水量对优质强筋小麦产量和品质的影响.结果表明,在同一施氮量条件下,表现为花后土壤含水量过高(80%～90%)或过低(40%～50%)导致穗粒数减少,千粒重降低,最终使产量降低.在同一土壤含水量下,表现为增加施氮量有利于提高穗数,但过多(300kg/hm2)或过少(150kg/hm2)施氮均不利于穗粒数和千粒重的提高,而导致减产.在同一土壤含水量下,总蛋白质、醇溶蛋白、麦谷蛋白含量及谷/醇比随着施氮量的增加而增加.在同一施氮量条件下,总蛋白质及各组分均随着土壤含水量的增加而降低,同时谷/醇比也降低.在同一施氮量下,花后土壤含水量过高(80%～90%)或过低(40%～50%)均不利于淀粉及其组分含量的提高.在同一土壤含水量下,过高(300kg/hm2)或过低(150kg/hm2)施用氮肥均不利于淀粉及其组分含量的提高.只有保持适宜的花后土壤含水量和施适宜的氮肥才有利于支/直比的提高.适量增施氮肥或花后土壤含水量适宜可提高小麦的加工品质.这说明在小麦生产中可以通过施用氮肥和控制花后土壤水分含量技术,调控小麦品质和产量的形成,从而实现优质高产.     

氮、钾营养对烤烟产量、产值和优质烟叶比例的影响

通过田间小区试验,研究氮素和钾素对烤烟产量、产值及优质烟叶(中上等烟叶)比例的影响,结果表明：(1)烤烟产量与施钾肥量具有显著正相关,并与施氮肥量有关;(2)产值与施氮肥量呈显著二次曲线相关性;(3)中上等烟比例与施肥比例(N／K)呈显著负相关,与施钾量、烟叶含钾量、土壤供钾能力有关。试验区烤烟优质、适产,要求施氮量(N)105一l12．8kg／hm2,施钾量(K)217．95—261．45kg／hm2,施肥比例(N／K比)0．40—0．48(N：K＝1：2．1—2．50或N：K2O＝1：2．5—3．0)。     

不同施氮水平对巨桉幼树耐旱生理特征的影响

采用盆栽方法,研究了巨桉幼树在N0(不施氮)、N1(1.4g尿素·盆-1)、N2(2.8g尿素·盆-1)3个氮处理水平下,连续干旱不同时间[分别停水0(D0)、3、6、9、12、15、18d]时巨桉的生理响应。结果显示:(1)除D0外,试验期内N1和N2处理的巨桉叶片含水量(LWC)、叶片相对含水量(LRWC)和叶片保水力(LWHC)基本低于N0水平,尤其在干旱中期最为明显,表明在干旱胁迫前施氮可能对巨桉叶片水分生理产生负面作用。(2)干旱初期,氮处理间的可溶性蛋白(SP)和可溶性糖(SS)含量的差异不大,而干旱处理后期(9~18d),N0处理的SP和SS较初期明显增加,但N1和N2处理相对于N0变化较为平缓,表明施氮不利于SP和SS积累;N1和N2处理下脯氨酸(Pro)含量的增幅随着干旱胁迫时间的延长明显大于N0处理。(3)随干旱时间延长干旱程度加重,N1、N2处理巨桉叶片过氧化氢(H2O2)和丙二醛(MDA)含量明显高于N0处理,表明施氮使得巨桉在干旱条件下水分缺乏更为严重,产生更多的活性氧(ROS)。(4)整个干旱处理期内,施氮并未显著改变巨桉的超氧化物歧化酶(SOD)活性和抗坏血酸(AsA)含量,但N1和N2的过氧化物酶(POD)活性明显高于N0。(5)施氮增加了巨桉叶片的色素含量并在干旱初期和中期保持较高水平,在干旱初期(0~3d)增加了巨桉叶片的净光合速率(Pn),但随着干旱时间的延长而迅速下降;施氮(N1、N2)的蒸腾速率(Tr)和气孔导度(Gs)在干旱初期均显著小于N0,但在干旱中后期(6d以后)各处理间差异不显著且均处于极低水平。研究表明,水分充足时施氮有助于增强巨桉的光合同化能力,促进其生长,但遇到持续干旱时施氮更易面临水分亏缺,降低其抵抗干旱的能力,因此在巨桉人工林的经营管理过程中,不应在干旱或季节性干旱即将到来之前施氮,若干旱过程中需施氮则应采取灌溉等途径保证其充足的水分供应。     

施氮时期对玉米土壤硝态氮含量变化及氮盈亏的影响

在“郑单 95 8”(9株 / m2 )组成的土 -植系统 ,研究了不施氮、基施氮 10叶展追氮、基施氮 吐丝期追氮和基施氮 乳熟期追氮共 4个处理下 0～ 2 0 0 cm的土壤 NO- 3- N含量在夏玉米生长期间的变化和土壤氮素的表观盈亏量 ,结果表明 :2 0 cm以上的土壤 NO- 3- N含量以大口期为界、2 0 cm以下的土壤 NO- 3- N含量以吐丝期为界前降后升。在 0～ 2 0 cm土层 ,与不施氮相比 ,施氮能增加土壤 NO- 3- N含量 ,而且吐丝期和乳熟至成熟阶段的 NO- 3- N含量在 10叶展期和吐丝期各自追氮后均显著增加。在 2 0～4 0 cm土层 ,乳熟期的 NO- 3- N含量施氮后明显比不施氮高。在 80 cm以下土层 ,施氮后的土壤 NO- 3- N含量明显比不施氮高 ;追氮期相比 ,后一追氮处理在乳熟期和成熟期的 NO- 3- N含量均比前一追氮处理明显增加 ,其中成熟期基施氮 乳熟期追氮处理在 16 0～ 2 0 0 cm土层的 NO- 3- N含量比基施氮 吐丝期追氮处理 (为 2 5 .3m g N/ kg(干土 ) )高 16 %。土壤氮素的表观盈余发生在吐丝期之前且 80 %以上盈余量出现在大口期前 ,表观亏损出现在吐丝期以后且其亏损量在乳熟期前后各占一半。经玉米季后 ,本试验中不施氮处理出现表观盈余 (为 5 6 .3kg N/ hm2 ) ;施氮后表观盈余量增加 ,主要是施氮减少了吐丝以后     

黄淮海平原玉米施氮量对后茬小麦土壤剖面硝态氮和产量的影响

在冬小麦-夏玉米一年两熟模式下,玉米品种“郑单958”（植株密度9株/m^2）和小麦品种“93-9”（基本苗704株/m^2）,冬小麦基施144kg N/hm^2,研究了玉米5个施N量（0、90、180、270和360kg/hm^2）对后茬小麦期间土壤剖面硝态氮含量、无机氮总量,以及小麦氮素吸收利用和产量的影响.结果表明：（1）与不施氮相比,玉米施氮显著增加小麦季0～200cm土壤硝态氮含量;自拔节起,0～40cm、0～130cm和0～200cm硝态氮含量均随施氮量增加而递增,在硝态氮含量较高的小区增幅也大.（2）轮作一周期后,不施氮和施氮360kg/hm^2显著影响0～130cm和0～200cm无机氮总量,但在90～270 kg/hm^2之间,施氮量的影响不明显.（3）施氮小于180kg/hm^2时,成熟期小麦植株氮素和籽粒氮素积累量、氮肥利用率均随施氮量增加而递增,但不明显.（4）与不施氮相比,施氮90kg/hm^2的小麦产量和麦玉轮作总产均增加但不明显,施氮180 kg/hm^2均显著增加,施氮270kg/hm^2与180kg/hm^2无明显差异.本试验条件下,夏玉米施氮90～180 kg/hm^2是适宜的.     

根系分区交替灌溉条件下水肥供应对番茄果实硝酸盐含量的影响

为了研究根系分区交替灌溉条件下灌水量和氮、磷、钾肥及有机肥用量对番茄果实硝酸盐含量的影响,采用五元二次正交旋转组合设计,通过盆栽试验,建立了番茄果实中硝酸盐含量与水肥因子的数学模型,并对各单一因素的效应及两两因素的耦合效应进行了分析。结果表明,在其他因子为中间水平时,番茄果实中的硝酸盐含量,随灌水量呈先降低后增加的变化规律;随施氮量和施磷量呈先增加后降低的变化趋势;随有机肥用量呈逐渐增加的趋势;但不受钾肥用量的影响。交互效应表现为,施磷量与有机肥用量、施氮量与施磷量间的相互作用会促使番茄果实硝酸盐含量提高;灌水量与施钾量和有机肥量、施氮量与施钾量间的相互作用有利于降低番茄果实硝酸盐累积。耦合效应表现为,除不施有机肥时随灌水量增加番茄果实硝酸盐含量显著增加外,对于其它任何有机肥及钾肥施用水平,果实硝酸盐含量皆随灌水量增加呈先减小后增加趋势;灌水量高于中水平时,番茄果实硝酸盐含量随着钾肥与有机肥用量的增加而减少。不论施磷量与施钾量如何变化,番茄果实硝酸盐含量皆随施氮量呈现先增加后减小的变化趋势,降低氮肥用量同时提高磷肥用量有利于降低番茄果实硝酸盐累积,而提高施钾量仅在施氮量高于中水平时能显著降低番茄果实硝酸盐含量。适当增加磷肥用量、减小有机肥用量能显著降低番茄果实硝酸盐的累积。     

香樟凋落叶分解对辣椒生长的抑制作用及施氮的缓解效应

采用盆栽试验,研究了香樟凋落叶分解对辣椒生长、生理特性和发育节律的影响及施氮对凋落叶分解效应的影响.试验设置对照(CK,每盆0 g)和每盆25 g(L25)、50 g(L50)、100g(L100)3个水平凋落叶处理,凋落叶分解39 d后开始施氮处理(每盆3.0 g尿素,分6次施入).结果表明:凋落叶分解明显抑制了辣椒的叶面积、株高、基径和生物量积累,且施用量越大,作用越强,持续时间越长;低量处理(L25)即可使其蕾数在观察期内(分解55~75 d)平均减少88.7%,96 d时的结实植株率减少40%,而中高量处理(L50和L100)下无植株现蕾和结实;各水平凋落叶处理的辣椒光合色素含量与净光合速率(Pn)几乎均低于CK;过氧化氢(H2O2)含量升高,超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性升高,丙二醛(MDA)含量仅在高量处理(L100)下显著上升;施氮可明显减轻辣椒生长发育受抑制的现象,各凋落叶处理的辣椒叶面积在施氮后52 d,株高、基径、生物量在施氮后83 d几乎恢复至CK水平,现蕾和结实率也得以明显提升.     

气候与土壤对烤后烟叶类胡萝卜素和表面提取物含量的影响

选择贵州生态条件差异较大的威宁县、开阳县和天柱县进行客土田间小区试验,以云烟85为材料,探讨气候与土壤对烤后烟叶类胡萝卜素和表面提取物含量的影响.结果表明:类胡萝卜素和表面提取物含量受生态条件的影响较大,地域性差异显著,打破犁底层耕作方式无明显作用.类胡萝卜素含量有随海拔高度增加而升高的趋势,但海拔高度的影响存在阈值效应;清香型烟叶的表面提取物含量明显高于中间香型.不同生态因子的影响程度明显不同,气候是关键生态影响因子.类胡萝卜素含量气候间的变异度是土壤的2-3倍,气候对β-胡萝卜素与叶黄素含量变异的贡献率分别为74％和64％,土壤贡献率分别为9％和12％.影响较大的前3个气候因子为大田生长前期的累积日照时数和累积降水量、成熟期的相对湿度,前3个土壤因子为有效钾、pH值和有效磷.表面提取物含量气候间的变异度是土壤的3-4倍,气候对腺毛分泌物与烷烃类蜡质含量变异的贡献率分别为61％和63％,土壤贡献率分别为13％和7％.影响腺毛分泌物含量的前3个气候因子为大田生长前期的平均气温、成熟期的相对湿度和≥10℃积温,前3个土壤因子为有效钾、有效铜含量和pH值.烷烃类蜡质含量的前3个气候影响因子为大田生长前期的累积降水量和平均气温、成熟期的平均气温,前3个土壤因子为有效锰、有效磷含量和阳离子交换量.土壤因子对烤后烟叶类胡萝卜素含量部位特征的影响较气候因子突出,气候因子对表面提取物含量部位特征的影响较土壤因子明显.     

钾肥及与秸秆配施对紫色土作物产量和微生物群落结构的影响

基于紫色菜园土壤莴笋-白菜-甜玉米轮作4年12季连续定位施钾肥试验,研究不同种类钾肥及用量对重庆地区紫色菜园土上作物产量和土壤微生物群落结构的影响,为该地区作物生产确定合理的施钾技术提供科学依据。结果表明,在施用氮磷肥基础上,不同钾肥处理莴笋、白菜、甜玉米产量均显著提高;从3种作物4年平均产量和钾肥效益看,以单施适量化学钾(K_2)、单施适量秸秆钾(M_2)和秸秆还田配施少量化学钾(K_1+M_1)的施钾肥模式对白菜的增产效果好,增产28.05%—30.27%;M_2和K_1+M_1施钾肥模式对莴笋的增产效果较好,增产13.89%和13.81%;K_1+M_1施钾肥模式对甜玉米的增产效果最好,增产15.10%,表明秸秆还田配施少量化学钾(K_1+M_1)模式在供试3种作物生产中具有很好的应用前景。不同施钾处理对土壤微生物群落结构及丰度均会产生一定影响,以秸秆还田配施少量化学钾肥(K_1+M_1)对提高土壤细菌、真菌、革兰氏阳性菌的作用较好,并显著增加土壤微生物总PLFA含量,缓解对土壤微生物生存环境的胁迫,说明K_1+M_1能为土壤微生物的生长繁育创造有利环境。莴笋、白菜、甜玉米3种作物4年平均产量与土壤细菌、真菌、革兰氏阳性菌和革兰氏阴性菌数量间存在显著相关性(P0.05),而不同钾肥处理对土壤微生物特征具有一定影响,说明施钾肥可能会调节土壤微生物特征,从而促进作物增产。     

施氮频率和强度对内蒙古温带草原土壤pH及碳、氮、磷含量的影响

以内蒙古温带典型草原为研究对象,通过 9 个氮沉降梯度以及一年 12 次和一年 2 次的施氮频率比对,经过4年的氮沉降模拟,研究不同氮沉降强度和频率对不同土层土壤 pH 及碳、氮、磷含量的影响.结果表明: 随着施氮强度的增加,土壤 pH 及全磷含量逐渐降低,但土壤有效氮和有效磷的含量呈增加趋势,可溶性有机碳(DOC)含量无明显变化规律,而土壤全碳、全氮含量基本保持不变.与更接近于自然氮沉降状况的一年 12 次施氮相比,一年 2 次施氮明显高估了氮沉降在降低土壤 pH和增加有效磷含量上的作用,低估了氮沉降在增加土壤有效氮含量上的作用,其中0～5 cm土层差异显著.     

Reliability of Analyses of Hg,Fe, Ca,K, P,pH, Alkalinity,Conductivity, Hardness and Colour from Lakes

The aim of this report has been to present results concerning analytical quality controls of Hg analysis of fish and sediment, analyses of Fe, Ca, total-P, K, pH, alkalinity, conductivity, colour and hardness (Ca + Mg) of lake water samples. Despite the fact that these are standard parameters in many regular water control programs, there are major differences in the reliability with which these parameters can be determined. The focus here is on an overall inter-laboratory comparison between the parameters. Six laboratories have been involved in the analysis. Selected results: pH gives the lowest (average) relative standard deviation (error), about 2 %; conductivity gives an error of about 5–7 %; alkalinity yields an average error of as much as 13–25 %, which is the largest among the parameters studied here; colour also gives a high error, 9–15 %; hardness gives a relative standard deviation of about 6–7 %. Of the other parameters (i. e., Hg, Fe, Ca and P), Hg gives the best reliability and Fe and P the lowest. To have knowledge of the reliability of the analytical data is of paramount importance in most control programs and research projects.     

Uniform hypothesis of cell behavior--movement, contact inhibition of movement, adhesion, chemotaxis, phagocytosis, pinocytosis, division, contact inhibition of division, fusion.

The cell has been represented as a charged liquid drop. Contrary to the DLVO-theory, the effect of the surface potential upon the value of the interfacial tension of the cell membrane has also been taken into consideration. The cell membrane has visco-elastic properties and its constituents may move against each other. Cell movement is caused by the appearance of a small number of the electrically charged constituents of the cell membrane on the leading edge of the cell. This produces a local decrease in the surface tension and the cell membrane expansion. At the moment of contact between two cells proton transfers occur between the strongly negatively charged microvilli of one cell and the body of the other, analogous to a condenser breakdown. This, through the effect on the surface tension, causes contact inhibition of movement. The distribution of the proton dissociable groups modifies the interaction between the cells (differentiation) and between the cell and the substratum (adhesion). Adsorption of the charged compounds at the surface of the cell membrane, decreasing the surface potential and increasing the surface tension, causes the phenomena of chemotaxis, phagocytosis and pinocytosis. Cell division, considered in the terms of the surface energy, requires an adequate supply of considerable quantities of energy inversely proportional to the surface potential value. In case of a reduction of the distance between the cells, their surface potential and the energetic barrier of the cell division processes increases, and causes contact inhibition of cell division. Due to their high charge, division of neoplastic cells is inhibited much later than division of normal cells, or is completely ininhibited due to geometric conditions. Fusion of the cell membrane in the intra-cellular and intercellular processes is a reverse process in relation to the cell division.     

The Effect of Age and Gender on Al, B, Ba, Ca, Cu, Fe, K, Li, Mg, Mn, Na, P, S, Sr, V, and Zn Contents in Rib Bone of Healthy Humans

The effect of age and gender on major, minor, and trace element contents in the intact rib bone of 80 relatively healthy 15–55-year-old women and men was investigated. Contents or upper limit of contents of 16 chemical elements in the rib bone were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Mean values (M?±?SΕΜ) for the mass fraction of Ba, Ca, Cu, Fe, K, Li, Mg, Na, P, S, Sr, and Zn (milligram per kilogram of dry bone) were as follows: 2.54?±?0.16, 171,400?±?4,050, 1.35?±?0.22, 140?±?11, 1,874?±?71, 0.049?±?0.011, 2,139?±?38, 5,378?±?88, 75,140?±?1,660, 1,881?±?51, 291?±?20, and 92.8?±?1.5, respectively. The upper limits of contents of Al, B, Mn, and V were <7.20, <0.65, <0.36, and <0.03, respectively. Statistically significant tendency for the Ca, Mg, and P content to decrease with age was found in the human rib bone, regardless of gender. The mass fraction of Fe in the male rib bone increases with age. It was shown that higher Ca, Mg, Na, P, and Sr mass fractions as well as lower Fe content were typical of female ribs as compared to those in male ribs.     

Distribution of N,P, K,Ca, Mg,S, Zn,Fe, Mn and Cu in groundnut

Summary Concentration of N, P, K, Ca, Mg and S in summer groundnut crop was higher than in kharif while Zn, Fe, Mn and Cu contents were higher in summer crop. Kernel's N, P and Zn; Leaflet's Ca and Mn; Stem's K and Fe; Root's S and Cu and Petiole's Mg contents were highest. Shell's N, P, K, Mg, S, Zn and Cu; Kernel's Ca, Fe and Mn contents were the least. N, P, K, S, Zn and Cu concentrations decreased linearly as the crop grew. Ca, Mg, Fe and Mn concentrations did not display any distinct pattern. Ca concentration was positively correlated with pod yield in both the seasons.     

Synthesis,tautomerism, and antimicrobial,anti-HCV,anti-SSPE,antioxidant, and antitumor activities of arylazobenzosuberones

2-Dimethylaminomethylene-1-benzosuberone 1 was coupled with diazotized aniline derivatives to afford a series of the hitherto unreported 2-arylazo-1-benzosuberones 3a–i. The tautomeric structure and the effect of substituents on the tautomeric form (s) of the products 3a–i were discussed. Similar coupling of the enaminone 1 with diazonium salts of heterocyclic amines gave the respective fused azolotriazino-benzosuberones. Some of the newly synthesized compounds showed potent antimicrobial, anti-HCV, antioxidant, antitumor (as topoisomerase I inhibitors), and antimicrobial activities.