优化高压电场处理对谷子种子萌发期内源激素的影响

为了探讨高压电场处理谷子种子内源激素含量动态变化对其萌发活力的调控影响,以农大八号谷子种子为试材,运用二次通用旋转组合设计与主成分分析相结合的方法,建模寻优。在优化电场处理条件下,研究种子萌发过程中内源激素含量动态变化。结果表明:高压电场处理谷子种子显著影响其萌发活力(P0.05);模型决定系数R2为0.979 2,表明模型拟合较好;模型耦合效应表明,高压电场处理谷子种子存在阈值效应,且电场强度影响效应大于处理时间;模型解析得到高压电场优化条件为电场强度340 k V/m,处理时间14 min。谷子种子萌发期内源激素含量动态变化结果表明,优化电场处理条件诱导吲哚乙酸(indole-3-acetic acid,IAA)、玉米素核苷(zeatin riboside,ZR)和赤霉素(gibberellin,GA)含量增加,抑制脱落酸(abscisic acid,ABA)含量增加;种子萌动前后,内源IAA、GA迅速上升、ABA快速下降,ZR在萌动时也达到极值,有利于胚根突破种皮,促进种子的萌动;GA/ABA、IAA/ABA、ZR/ABA比值处理均高于对照(未经电场处理),表明高压电场处理谷子种子后内源激素比值的变化是种子萌发活力提高的诱因,胚根达种子的2倍长后,GA/ABA、IAA/ABA比值都呈现增大趋势,表明幼苗生长与其调控密不可分。研究结果为高压电场技术处理种子在农业生产中的应用提供理论依据。     

多裂骆驼蓬对食荚豌豆的化感作用研究

试验研究了多裂骆驼蓬醇提取物浸种对食荚豌豆种子萌发、幼苗生长及生理生化性状的影响。结果表明,多裂骆驼蓬醇提取物浸种显著抑制食荚豌豆种子的萌发和幼苗生长,萌发率、发芽指数和与萌发有关的淀粉酶活性降低,株高、根体积、根系和地上部干重减小,根茎比下降;多裂骆驼蓬醇提取物浸种处理的幼苗根系活力和叶片硝酸还原酶活性、叶绿素和可溶性蛋白质含量下降;超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性降低,丙二醛(MDA)含量和过氧化物酶(POD)活性升高,根系过氧化物同工酶表达受抑。     

外源谷胱甘肽对嫁接黄瓜砧穗种子萌发过程中自毒胁迫的缓解效应

为探讨外源谷胱甘肽(GSH)对自毒作用的缓解效果和生理作用机制,以连作嫁接黄瓜根际土壤浸提液模拟自毒胁迫,在100g·L~(-1)浓度土壤浸提液中分别添加0、25、50、100、200 mg·L~(-1)GSH,进行黄瓜、南瓜种子萌发试验,分别测定发芽率、主根长度、根系表面积、根尖数、α-淀粉酶活性、淀粉酶总活性和脯氨酸含量等指标。结果表明,土壤浸提液处理后,黄瓜和南瓜种子的发芽率、发芽指数、活力指数、主根长度、根尖数、根系表面积、α-淀粉酶活性、淀粉酶总活性得到显著抑制,脯氨酸含量升高。在自毒作用下,外施不同浓度GSH,可不同程度地提高种子发芽率、发芽指数、活力指数、主根长度、根系表面积、α-淀粉酶活性、淀粉酶总活性,降低脯氨酸含量。土壤浸提液能对黄瓜、南瓜种子产生自毒作用,添加外源GSH能诱导黄瓜和南瓜种子内淀粉酶活性增强,有效缓解自毒作用对黄瓜、南瓜种子萌发和幼苗生长的抑制作用,并且以100 mg·L~(-1)GSH缓解效果最显著。本研究结果为制定缓解嫁接黄瓜连作障碍措施提供了理论依据。     

外源NO对Ca(NO3)2胁迫下黄瓜幼苗生长和抗氧化系统的影响

本研究以黄瓜为试材,采用营养液水培,研究了外源NO对Ca(NO3)2胁迫下黄瓜幼苗生长和抗氧化酶系的影响.结果显示,在70mmol·L-1的Ca(NO3)2胁迫下,植株生长受到抑制,干重和叶绿素含量显著下降,叶片和根系抗氧化酶SOD、POD、CAT和APX活性均升高,膜脂过氧化产物MDA及可溶性 蛋白含量增加.而叶面喷施NO供体SNP显著缓解了Ca(NO3)2胁迫对黄瓜幼苗生长的抑制,植株干重显著增加.同时,抗氧化酶活性、可溶性蛋白和叶绿素含量也有不同程度的上升,MDA含量显著下降.以上表明,NO能够增强黄瓜幼苗对Ca(NO3)2胁迫的耐性.喷施SNP对正常营养液培养的黄瓜幼苗无显著影响.     

硼钙营养对胡柚果实激素及相关酶代谢的影响

连续2年对胡柚进行叶面喷施硼(B)、钙(Ca)及硼加钙(B+Ca)试验,以探讨B、Ca及其互作对胡柚果实吲哚乙酸(IAA)、赤霉素(GA3)、脱落酸(ABA)等内源激素代谢的影响效应。结果表明,B及B+Ca处理明显降低胡柚果实的IAA、GA3、ABA的含量及果实发育前期的ABA/(IAA+GA3)比率,降低了IAA氧化酶的活性,提高了过氧化物酶(POD)的活性;Ca处理对激素代谢的影响效应相对较小。     

黄瓜幼苗内源激素和多胺对NO3-胁迫的适应性变化研究

通过溶液培养试验,研究了黄瓜幼苗内源激素和多胺对NO3-胁迫的适应性变化研究。结果表明,黄瓜幼苗在56~98 mmol/L NO3-浓度范围内培养7 d,根中ZR、GA和IAA含量均比对照显著升高;ABA含量降低。说明在此浓度范围内,根系有关酶活性首先被激活,从而引起促进生长的激素合成加速;而ABA等促进衰老的激素合成受抑,黄瓜生长势增加。叶中激素变化规律与根中正好相反,说明主导黄瓜幼苗生长的关键激素是根中相关激素的变化。当NO3- 浓度达140 mmol/L时,叶片中ZR、GA、ABA和IAA含量比对照极显著升高;而根中ZR、GA和IAA含量开始降低,ABA含量开始升高,幼苗生长受到严重抑制,从而加速了幼苗的衰老。叶片中Spm和Spd及根中Spm含量在一定浓度范围内,均随NO3-浓度的增加而升高,当NO3-浓度高于140 mmol/L时,其含量反而开始降低;叶片中Put含量均明显低于对照。而叶片和根中（Spd+Spm）/Put比值却显著高于对照。结果表明,黄瓜幼苗内各种激素之间通过此消彼长的变化过程,以提高对高浓度NO3- 胁迫的抗性。     

激素对陆地棉矮化突变体AS98的生理影响

分别用外源激素GA3、BR和IAA处理棉花极端矮化突变体AS98,比较分析突变体内源激素GA、IAA、ZR和ABA的含量、α-淀粉酶、POD和SOD活性变化,探索该矮化突变体的矮化机理。结果显示,施用外源GA3能显著增加AS98叶片GA、IAA、ZR和ABA的含量,GA的相对变化值(VR)为60.4%～64.5%,IAA的VR为6.8%～12.3%,ZR的VR为11.7%～30.7%,ABA的VR为45.7%～82.3%;低浓度外源IAA对AS98的内源GA和IAA的合成具有一定的促进作用,其VR分别为49%和0.67%,外源IAA对ZR的合成具有抑制效应,其VR为-21.5%～-30.2%,对ABA的合成具有一定的促进效应,其VR为5.1%～35.4%;外源BR对AS98的内源GA和ABA的合成具有促进作用,其VR分别为25.3%～30.4%和3.0%～65.6%,对ZR的合成具有抑制作用,其VR为-32.1%～-40.9%,而对IAA的合成具有明显的浓度效应,低浓度促进IAA合成,高浓度抑制IAA合成。外源GA3对AS98的α-淀粉酶活性影响具有浓度效应,低浓度具有促进作用,0.3μmol/L的GA3使α-淀粉酶活性提高82%。PP333对α-淀粉酶活性具有抑制作用,1.2μmol/L的PP333使α-淀粉酶活性降低42%,而且PP333对α-淀粉酶活性的抑制作用可以通过施用GA3得到恢复。PP333对SOD活性有促进作用,1.5μmol/LPP333SOD活性提高35%,而GA3对SOD活性具有抑制作用,1.5μmol/L使SOD活性降低48%。结果表明,AS98是一个GA缺陷型矮化突变体,施用外源GA3能使促进和抑制生长的内源激素显著增加,同时,使α-淀粉酶活性增加,POD和SOD活性降低,而PP333对α-淀粉酶活性的抑制作用可以通过施用GA3得到恢复。     

黄瓜地上部水浸液对番茄的化感抑制效应

采用培养试验研究了黄瓜地上部水浸液对番茄的化感作用及其生理生化机理,并用试管法对其水浸液的主要化学成分进行定性分析.结果表明,黄瓜地上部水浸液含有生物碱、酚类、有机酸、皂甙、甾体、多糖、蛋白质和油脂,不含鞣质.黄瓜地上部水浸液处理显著抑制番茄种子萌发过程中的呼吸速率和α-淀粉酶活性,使种子萌发率和萌发指数降低,其抑制作用随处理浓度提高而增强.在番茄幼苗生长过程中浇灌黄瓜地上部水浸液提高了番茄叶片中超氧阴离子(O2)、H2O2和丙二醛(MDA)的含量及质膜透性;降低了过氧化氢酶(CAT)和过氧化物酶(POD)活性,还原型谷胱甘肽(GSH)和抗坏血酸(ASA)含量提高,而超氧化物歧化酶(SOD)和抗坏血酸过氧化物酶(APX)活性随处理浓度增加先升后降;叶绿素含量、净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)降低,胞间CO2浓度(Ci升高,幼苗干重下降.叶绿素荧光动力学资料显示,番茄叶片的初始荧光(Fo)随着处理浓度提高而增大,最大荧光(Fm)、PSⅡ潜在光化学效率(Fv/Fo)、PSⅡ原初光能转换效率(Fv/Fm)、PSⅡ光合电子传递量子效率(ΦPSⅡ)、光化学猝灭系数(qP)、表观光合电子传递速率(ETR)和光化学速率(PCR)下降,非光化学猝灭系数(NPQ)先升后降,表明叶片光合机构受到伤害.     

盐胁迫下两种基因型冬小麦萌发过程中钠离子吸收及对碳、氮代谢的影响

采用两种基因型冬小麦种子为试验材料,研究了盐胁迫对小麦种子萌发过程中Na 的吸收和累积及其对C、N代谢的影响及外源Ca(NO3)2和CaCl2对小麦萌发过程中盐害的缓解效应。结果表明,150mmol/L NaCl胁迫明显抑制小麦种子的萌发。种子萌发过程中,"小偃6号"的耐盐性优于"陕229"。外源钙对两种小麦盐胁迫效应的缓解作用不同。6mmol/L钙离子可明显减轻"陕229"的盐害作用,对"小偃6号"作用不大。盐胁迫对种子萌发过程中的蛋白酶和淀粉酶活性具有明显抑制作用。盐胁迫下,"小偃6号"种子的蛋白酶和淀粉酶活性明显高于"陕229"。钙离子对盐胁迫下小麦萌发过程胚乳内蛋白酶的活性有较大调节作用,对淀粉酶活性影响较小。盐胁迫下小麦种子中Na 含量显著增加,K/Na比显著降低。钙离子对盐胁迫下小麦种子中Na 累积的影响较大,盐胁迫和外源钙处理对K 含量影响较小。     

Cu~(2+)对黄瓜发芽期发育和生理特性的影响

研究了Cu2+浓度对黄瓜发芽期发育和生理特性的影响。结果显示,低浓度Cu2+(25 mg/L)处理对黄瓜种子萌发和幼苗生长有促进作用,其种子发芽率、发芽势、发芽指数、活力指数、根长、下胚轴长、下胚轴粗度、生物量和相对含水量均高于对照及其他浓度处理;而幼苗的质膜相对透性、丙二醛含量、可溶性糖含量、脯氨酸含量及保护酶活性均在此浓度得达最低。但在高浓度Cu2+(Cu2+浓度在50~300mg/L时)处理下,随着Cu2+浓度增加,黄瓜种子萌发的各项指标开始下降,幼苗生长的各项生理指标开始上升,对黄瓜种子发芽和幼苗生长产生抑制作用,并在300mg/L时抑制作用最显著。     

固态13C和15N核磁共振法研究15N标记土壤的腐殖质组分

Five humic fractions were obtained from a uniformly ^15N-labelled soil by extraction with 0.1 mol L^-1 Na4P2O7,0.1mol L^-1 NaOH ,and HF/HCl-0.1 mol L^-1 NaOH,consecutively,and analyzed by ^13C and ^15N CPMAS NMR (cross polarization and magic angle spinning nuclear magnetic resonace).Compared with those of native soils humic fractions studied as a whole contained more alkyls ,methoxyls and O-alkyls,being 27%-36%,17%-21%and 36%-40%,respectively,but fewer aromatics and carboxyls(bein 14%-20% and 13%-90%,respectively),Among those humic fractions ,the humic acid(HA)and fulvic acid(FA) extracted by 0.1 mol L^-1 Na4P2O7 contained slightly more carboxyls than corresponding humic fractions extracted by 0.1 mol L^-1 NaOH ,and the HA extacted by 0.1 mol L^-1 NaOH after treatment with HF/HCl contained the least aromatics and carboxyls.The distribution of nitrogen functional groups of soil humic fractions studied was quite similar to each other and also quite similar to that of humic fraction from native soils.More than 75% of total N in each fraction was in amide from,with 9%-13% present as aromatic and /or aliphatic amines and the remainder as heerocyclic N.     

葫芦科蔬菜对丛枝菌根真菌依赖性的研究

在盆栽条件下试验研究了5种葫芦科(Cucurbitaceae)蔬菜对2种丛枝菌根(Arbuscular Mycorrhiza，AM)真菌的依赖性。结果表明，AM真菌Glomus mosseae(G.m)和Gigaspora rosea(Gi.r)均能有效地促进葫芦科蔬菜的生长，显著增加叶面积和植株干物质量，提高叶片的光合速率，降低气孔阻力。供试葫芦科蔬菜对菌根的依赖程度顺序为黄瓜＞西瓜＞苦瓜＞葫芦＞南瓜。5种葫芦科蔬菜对AM的依赖性与AM真菌对根系的浸染率呈正相关关系，符合直线回归方程：y=117.19+0.7468x。     

增铵营养对番茄幼苗生长和有机酸含量的影响

A hydroponic experiment was conducted to study the effect of partial replacement of NO(3^-)-N by NH -N on theseedling growth and organic acid content of tomato (Lycopersicon esculentum Mill.). A completely randomized designwas established with three replications and five treatments, i.e., NO(3^-)-N/NH(4^ )-N of 100/0, 75/25, 50/50, 25/75 and0/100. Results showed that 25% replacement of NO(3^-)-N by NH(4^ )-N significantly (P = 0.05) improved fresh and dryweight, revealing that a proper percentage of NH -N was important for tomato nitrogen nutrition. This could increasethe plant growth even though tomato was a crop that preferred nitrate nutrition. Also an increase in the proportion ofNH -N in the nutrient solution led to a significant decrease (P=0.05) in malate, citrate and fumarate. However, the25% NH(4^ )-N plus 75% NO(3^-)-N treatment had no significant effect (P = 0.05) on the 2-ketoglutarate, succinate or oxalicacid content, showing that only some organic acids in tomato plants were affected. Only pyruvate increased significantly(P=0.05), and it only increased for 25% and 50% replacement of NO(3^-)-N by NH(4^ )-N. Metabolism of these organicacids, especially malate, citrate and fumarate, should be further studied at the molecular level in vegetables applied withdifferent nitrogen forms.     

NH4+-N/NO3--N比例对不同不结球小白菜品种的生长和部分生理指标的影响

The responses of three cultivars of Chinese cabbage (Brassica chinensis L.), one of the main vegetable crops in China, to different ratios of NH4+-N/NO3--N was investigated to find the optimal ratio of ammonium to nitrate for maximal growth and to explore ways of decreasing the nitrate content, increasing nitrogen use efficiency of Chinese cabbage, and determining distributions of nitrogen and carbon. Three cultivars of Chinese cabbage were hydroponically grown with three different NH4+-N/NO3--N ratios (0:100, 25:75 and 50:50). The optimal ratio of NH4+-N/NO3--N for maximal growth of Chinese cabbage was 25:75. The increase in the ratio of NH4+-N/NO3--N significantly decreased nitrate content in various tissues of Chinese cabbage in the order of petiole > leaf blade > root. The highest total nitrogen (N) content was found when the ratio of NH4+-N/NO3--N was 25:75, and N contents in plant tissues were significantly different, mostly being in the order of leaf blade > petiole > root. At the NH4+-N/NO3--N ratio of 25:75, the biomasses of Chinese cabbage cultivars 'Shanghaiqing', 'Liangbaiye 1' and 'Kangre 605' increased by 47%, 14% and 27%, respectively. The biomass, SPAD chlorophyll meter readings and carbon content of 'Shanghaiqing' were all higher than those of 'Liangbaiye 1', while nitrate and total nitrogen contents were lower. Thus, partial replacement of nitrate by ammonium could improve vegetable production by both increasing yields and decreasing nitrate content of the plants.     

中国陕西省施有机肥黄土NH4+固定的热力学性质

Some thermodynamic properties of NH₄⁺ fixation by loess soil in plowing and clay layers are discussed. The results indicate that the four ion adsorption equations commonly used can describe the properties of NH₄⁺ fixation in these soils under constant temperature. Among the four adsorption equations, the single-surface Langmuir equation is the best. When the concentration of NH₄Cl solution is 10^-1 mol below, the Freundlich equation can be used. The changes of apparent standard free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) illustrate that NH₄⁺ fixation in soil is an endothermic adsorption and spontaneous reaction, and the process can be enhanced by a higher temperature and clay content in soil. The "proper value of NH₄⁺ fixation by soil (K₁ × q_m) increased with increasing clay content and temperature. The heat of NH₄⁺ fixation in soil (Q_m) confirms the conclusions made in this paper.     

土壤温度、水分和NH4+-N浓度对土壤硝化反应速度及N2O排放的影响

硝化反应是土壤、特别是干旱半干旱地区农业土壤N2O产生的重要途径之一。但是,目前环境条件对硝化反应中N2O排放的影响研究较少,而在国内外通用的几个模型中均用固定比例估算硝化反应过程中N2O的排放。本文通过砂壤土培养试验,研究了土壤温度、水分和NH4+-N浓度对硝化反应速度及硝化反应中N2O排放的影响,并用数学模型定量表示了各因素对硝化反应的作用,用最小二乘法最优拟合求得该土壤的最大硝化反应速度及N2O最大排放比例。结果表明,随着温度升高,硝化反应速度呈指数增长;水分含量由20%充水孔隙度(WFPS)增加到40%WFPS时,反应速度增加,水分含量增加到60%WFPS时反应速度略有降低;NH4+-N浓度增加对硝化反应速度起抑制作用。用米氏方程描述该土壤的硝化反应过程,其最大硝化反应速度为6.67mg·kg?1·d?1。硝化反应中N2O排放比例随温度升高而降低;随NH4+-N浓度增加而略有增加;20%和40%WFPS水分含量时,硝化反应中N2O排放比例为0.43%～1.50%,最小二乘法求得的最大比例为3.03%,60%WFPS时可能由于反硝化作用,N2O排放比例急剧增加,还需进一步研究水分对硝化反应中N2O排放的影响。     

不同铵硝配比对弱光下白菜氮素吸收及相关酶的影响

以黑色遮阳网覆盖模仿弱光环境, 使光照强度为自然光的20%左右, 以自然光照为对照, 采用精确控制水培溶液氮素营养, 研究NH₄⁺-N/NO₃^--N 比例分别为0/100、25/75、50/50、75/25、100/0 对弱光下白菜氮代谢及硝酸还原酶和谷氨酰胺合成酶活性的影响。结果表明, 弱光下, 白菜的鲜重及叶片总氮量以NH₄⁺-N/NO₃^--N 比为25/75 时最大, NH₄⁺-N/NO₃^--N 比为100/0 时最低。随弱光处理的进行, 白菜叶片中硝酸还原酶活性及谷氨酰胺合成酶活性均呈下降趋势, 但NH₄⁺-N/NO₃^--N 比为25/75 时, 可维持叶片内较高的硝酸还原酶活性及谷氨酰胺合成酶活性。试验表明, NH₄⁺-N/NO₃^--N 比25/75 是白菜在弱光下生长的较适宜氮素形态配比。     

不同液土比和温度条件下塿土铵离子吸附

Effects of NH₄⁺ concentration, solution/soil ratio and temperature on NH₄⁺ adsorption were studied in a Eum-Orthic Anthrosol. The slopes of the soil NH₄⁺ adsorption isotherms and the fitted n, the coefficient for the adsorption intensity, and k, the coefficient related to adsorption capacity, of the Freundlich equation increased with increasing solution/soil ratio (SSR) and with decreasing temperature (T). For the range of experimental conditions, the value of ∂q/∂c, the rate of change of the amount of NH₄⁺ adsorbed in the soil solid phase (q) with respect to the equilibrium concentration of NH₄⁺ in soil solution (c), was 0.840, indicating that q increased with increasing c. From 2 to 45 ℃, ∂q/∂SSR, the rate of change of q with respect to SSR, decreased from 2.598 to 1.996, showing that q increased with increasing SSR, while its increasing rate decreased with temperature. From SSR 1:1 to 20:1, ∂q/∂T, the rate of change of q with respect to T, decreased from -0.095 to -0.361, indicating that q decreased with increasing temperature, and at the same time the negative effect of temperature became larger as SSR increased. Thus under the experimental conditions the order of importance in determining the amount of NH₄⁺ adsorbed in the soil solid phase was ∂q/∂SSR > ∂q/∂c > |∂q/∂T|, indicating that the greatest effect on the amount of NH₄⁺ adsorbed was with the solution/soil ratio; the equilibrium concentration of NH₄⁺ had a lesser effect; and temperature had the least effect.     

固定态铵的含量及中国某些耕地土壤NH4+的固定能力

Fixed ammonium contents and NH4^ fixation capacities of some representative cultivated solis collected from 16 provinces of China were studied.Results showed that the contents of fixed ammonium in soils ranged from 35 to 573 mg N kg^-1,with an average of 198mg Nkg^-1.The content of fixed ammonium correlated very significantly with mica content for tropical and subtropical soils,whereas this was not the case for soils in the temperate zone.At the end of K-exhausting experiment the fixed ammonium content increased in most soils studied.However,it decreased in smom temperate soils.Generally,fixation of added NH4^ could not be found either before or after K-exhausting experiment for highly weathered soils,including tropical soils and soils derived from granite-gneiss or Quaternary red clays in the subtropic zone,while for most soils in the Yangtze River dalta the NH4^ fixation capacity was rather high and increased significantly in the K-exhausted soils.     

15N标记的土壤估测某些豆科植物N2固定的温室实验

Pot experiments were carried out to estimate N2 fixation by vetch,milk vetch,sickle alfalfa and broadbean in pure stand using a ^15N-labelled soil.Winter wheat was used as the non-fixing control.The 15N-labelled soil used was prepared by growing corn-wheat-corn successively on a nearly organic-matter-free Xiashu loess supplemented with adequate amounts of (15NH4)2SO4,P,K and micronutrients,then incorporating these 15N-labelled plant materials into the soil after each havest,and allowing the plant materials to be decomposed aerobically for 410d after incorporation of the plant material of the thire crop.The 15N enrichment of wheat plant-N varied slightly with organs,with a maximum difference of 9.8%,Based on 15N enrichment of soil N inferred from the mean value of the 15N enrichment in different organs of wheat 79%-91% of total N in the tops and 67%-74% of total N in the roots of legumes studied were derived from atmosphere .Estimate by isotope dilution method was in good agreement with that by the conventional difference method provided values obtained by the latter were corrected for seed N,and also with that from the measurement of N accumulated in the tops of the legumes.