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1.
曹玉  李素梅  施卫明  苏彦华 《土壤》2009,41(4):612-619
本文利用定量PCR技术分析了OsAMT1.2和OsAMT3.3在水稻根中的表达水平,并应用铵吸收功能缺陷型酵母突变体分析OsAMT1.2和OsAMT3.3对NH4+ 的转运功能及影响基因功能异源表达的可能因素.结果表明,OsAMT1.2和OsAMT3.3在分蘖期的表达水平较苗期高;苗期OsAMT1.2与OsAMT3.3的转录水平差异不显著,但分蘖期OsAMT1.2的表达水平快速升高,较苗期提高了5倍,而OsAMT3.3的表达量只提高了一倍,导致两者的表达水平存在显著差异.缺N处理2天两基因均有被诱导增强表达的趋势,其中苗期的增加幅度明显高于分蘖期.当外源供给1mmol/L NH4+,OsAMT1.2在铵吸收功能缺陷型酵母突变体上仅表现部分功能,而OsAMT3.3则不能实现吸铵功能互补.以AtAMT1.1为对照,分析OsAMT1.2在酵母中的表达水平,结果表明异源系统中OsAMT1.2的相对表达量仅有AtAMT1.1的50%.本文的结果说明,外源基因在酵母异源系统中的异源表达,除了与基因产物本身的功能有关,还取决于宿主酵母细胞对其表达水平的调控,因而表现出受内源机制调控的特征.  相似文献   

2.
赵首萍  施卫明 《土壤》2007,39(3):460-464
以水稻为材料,对水稻NH4 离子转运蛋白基因OsAMT1.1、OsAMT1.2、OsAMT1.3、OsAMT3.1和OsAMT4.1的表达部位进行了初步的定性研究,并首次将荧光定量PCR技术应用于植物营养研究中,检测了水稻根中OsAMT1.1、OsAMT1.2、OsAMT1.3和OsAMT4.1在N饥饿48h以后,又转移到1mmol/LNH4 或1mmol/LNO3-中2h后的表达量变化。结果表明,在当时的实验条件下,OsAMT3.1主要在地上部表达,因此推测可能对于根系吸收NH4 没有多大作用;OsAMT1.1、OsAMT1.2、OsAMT1.3和OsAMT4.1在植株根部和地上部都有表达;经过48h的N饥饿处理以后,在检测的4个基因当中,根中表达量最高的是OsAMT1.1,显著高于OsAMT1.2、OsAMT1.3和OsAMT4.1,由此认为,对根中NH4 吸收的贡献也是OsAMT1.1最大;OsAMT1.2、OsAMT1.3和OsAMT4.1表达量在N饥饿48h以后,不论是NH4 或NO3-的加入都显著抑制这3个基因的表达。荧光定量PCR方法的应用可以精确检测到基因表达量的微小变化,尽管没有显著的变化,但从表达量上来讲,OsAMT1.1表达量在加N后有下降的迹象,而且OsAMT1.1、OsAMT1.2和OsAMT4.1受NH4 的抑制效果稍强于NO3-;而OsAMT1.3受NO3-的抑制作用稍强一点,这些都是半定量PCR和Northern杂交所检测不到的。  相似文献   

3.
采用砂培实验研究NH4^+-N部分代替NO3^1-N对番茄的影响,结果表明:与全硝处理(100%NO3)相比较,增铵处理(NH4^+:NO3^-=25%:75%)下番茄鲜果重显著提高;同时叶片内NO3^--N含量随增铵而显著降低,叶片与果实内NH4^+-N含量及果实的可溶性蛋白含量随增铵而升高;增铵条件抑制了叶片和果实的硝酸还原酶(NR)活性,提高了叶片和果实的磷酸烯醇式丙酮酸羧化酶(PEPcase)活性及叶片谷氨酰胺合成酶(GS)活性,但对果实的谷氨酰胺合成酶(GS)活性影响不大。上述结果表明,NH4^+-N部分代替NO3^--N可增加番茄产量,提高集约化基地的生产量。  相似文献   

4.
5.
本研究以前期工作中筛选出的硝酸盐积累量存在显著差异的2个不同基因型小白菜品种为材料,在人工气候箱水培条件下研究了不同铵硝比例对小白菜硝酸盐积累量、硝酸还原酶活性(NRA)和硝酸盐吸收基因NRT1和NRT2的表达量的影响。结果表明,不同铵硝比例对小白菜硝酸盐积累量有显著影响,且存在基因型差异。四月慢对硝酸盐吸收、积累及同化利用的能力都强于华冠青梗菜,尤其是在高NO3- 比例处理时。与华冠青梗菜相比,四月慢对NO3- 的同化利用的能力更不易受铵硝比例的影响。NRT1和NRT2主要在根部表达,且NRT1的表达量显著高于NRT2,NRT1和NRT2的表达量变化规律只能在一定程度上解释小白菜不同基因型间硝酸盐积累量的差异,小白菜不同基因型品种间硝酸盐积累量差异的机理还需要进一步研究。  相似文献   

6.
增铵营养对低温胁迫下棉花幼苗氮代谢的影响   总被引:8,自引:3,他引:5  
【目的】探明增铵营养提高棉花幼苗抗低温胁迫能力的机制。【方法】以棉花新陆早13号为供试品种,在人工气候室内模拟不同温度处理(15℃和25℃),研究了不同铵硝态氮配比(NH4+-N/NO3--N分别为0/100、25/75、50/50、75/25、100/0)对低温(15℃)胁迫下棉花苗期生长、氮素吸收量及氮代谢相关酶活性的影响。【结果】常温条件(25℃)下,较单一铵、硝营养,铵硝混合营养显著提高棉苗各器官的生物量,地上部和根系干物质量在NH4+-N/NO3--N比为50/50处理时最大,单一铵营养处理时最小;对棉苗生物量的影响效果表现出铵硝混合营养处理优于单一铵、硝营养处理。低温胁迫(15℃)后棉苗各器官生物量减小,且差异显著。常温和低温条件下,随着营养液中NH4+-N比例增加,棉苗全氮含量逐渐递增,氮素吸收量先升后降;棉苗根系、茎秆及叶柄内硝态氮含量呈明显降低趋势;棉花幼苗叶片NR活性明显减小,相反,GS和GOGAT活性则极显著提高。常温处理下棉苗各器官的氮素累积量显著高于低温胁迫处理,低温抑制了棉苗对硝态氮的吸收,降低NR、GS和GOGAT活性。【结论】低温胁迫下,增铵营养可显著提高氮素养分含量,促进棉苗生长,同时通过提高GS、GOGAT等氮代谢相关酶活性,维持氮代谢平衡,增强棉花幼苗对低温的抗性。  相似文献   

7.
几种蔬菜对硝态氮、铵态氮的相对吸收能力   总被引:25,自引:1,他引:24  
采用溶液培养方法探讨了莴笋、菠菜、小白菜和大青菜 4种蔬菜作物对硝、铵态氮的相对吸收能力以及这两种氮源对它们生长发育的影响。结果表明 ,单独供给NO3-N ,4种作物均生长发育良好 ;供给NO3--N +NH4+-N(NO3-∶NH4+=1∶1) ,生长量均有所下降 ,而单独供给NH4+-N时 ,生长量则大幅度下降。莴笋单独供给NO3--N时 ,其吸氮量显著高于供给NO3--N +NH4+-N的处理 ,大青菜、菠菜供给NO3--N +NH4+-N与单独供给NO3--N相比吸氮量大体相当 ;小白菜同时供应NO3--N +NH4+N时吸氮量最高 ,供给NO3--N时次之 ,供给NH4+-N时显著降低。供给NH4+-N时 4种作物吸氮量均比其它氮源显著降低。 4种作物对NO3--N与NH4+-N的吸收具有明显的偏向性。供给等氮量铵、硝态氮 (NO3--N +NH4+-N处理 )时 ,菠菜、小白菜吸收的NO3-N显著多于NH4+-N ,表现出喜硝性 ,莴笋则与此相反 ,表现出喜铵性 ;而大青菜对两种形态氮素的吸收量相差不多 ,表现出兼性吸收的特点。但上述偏向性具有阶段特点 ,即喜硝作物可能在某一阶段表现出喜铵性状  相似文献   

8.
增铵营养对番茄植株伤流液组分及含量的影响   总被引:1,自引:1,他引:0  
在总氮(N)浓度相等的条件下,研究全硝营养(100% NO3-)和25% 增铵营养(NH4+∶NO3- = 25%∶75%)对开花期和幼果期番茄植株伤流液各组分含量的影响.结果表明,增铵营养显著增加幼果期伤流液中 K的含量,对Ca、Mg、P元素含量没有显著影响;增铵营养下伤流液中 NO3- 的含量下降、NH4+ 含量增加,氨基酸、苹果酸等的含量均显著增加,氨基酸/硝态氮含量之比显著提高,表明喜硝作物适当增铵不仅能够提高根系活力,显著促进K的吸收以供果实发育之需,而且提高了植株整体同化N素的能力.  相似文献   

9.
10.
不同铵硝比营养液对生菜生长发育影响的研究   总被引:14,自引:1,他引:13  
王波  沈其荣  赖涛  陈爱群  魏晋 《土壤学报》2007,44(3):561-565
氮素是作物生长所必需的营养元素之一。在一般情况下,作物能够吸收利用的氮素形态有多种。但从营养学角度来说,植物生长的主要氮源为NH4^+-N和NO3^-—N。由于作物本身遗传特性和营养特点以及环境条件的差异,作物对NH4^+-N和NO3^--N的吸收利用和适宜性也有不同。对蔬菜作物来说,  相似文献   

11.
有机配体、竞争阳离子和pH对土壤中Zn分解的影响   总被引:1,自引:0,他引:1  
A series of experiments were conducted to examine the interactive effects of an organic ligand, a competing cation, and pH on the dissolution of zinc (Zn) from three California soils, Maymen sandy loam, Merced clay, and Yolo clay loam. The concentrations of soluble Zn of the three soils were low in a background solution of Ca(NO3)2. Citric acid, a common organic ligand found in the rhizosphere, was effective in mobilizing Zn in these soils; its presence enhanced the concentration of Zn in soil solution by citrate forming a complex with Zn. The ability of Zn to form a complex with citric acid in the soil solution was dependent on the concentration of citric acid, pH, and the concentration of the competing cation Ca^2+. The pH of the soil solution determined the extent of desorption of Zn in solid phase in the presence of citric acid. The amounts of Zn released from the solid phase were proportional to the concentration of citric acid and inversely proportional to the concentration of Ca(NO3)2 background solution, which supplied the competing cation Ca^2+ for the formation of a complex with citrate. When the soil suspension was spiked with Zn, the adsorption of Zn by the soils was retarded by citric acid via the formation of the soluble Zn-citrate complex. The dissolution of Zn in the presence of citric acid was pH dependent in both adsorption and desorption processes.  相似文献   

12.
氮对水稻铵转运蛋白表达的调控   总被引:3,自引:0,他引:3  
  相似文献   

13.
Abstract

The form of nitrogen can affect root and shoot growth of plants. This study was conducted to determine the effects of ammonium and nitrate nitrogen on root length and number and shoot color and quality of creeping bentgrass (Agrostis palustris Huds. ‘Penncross'). The study was conducted in the University of Georgia rhizotron facility. Turf was grown in an 80/20 sand/peat rooting medium and maintained under putting green conditions for 12 months. Two forms of nitrogen, ammonium and nitrate, utilizing the nitrogen sources of urea and calcium nitrate, respectively, were applied in the following ammonium: nitrate ratios: 100: 0, 75: 25, 50: 50, 25: 75, and 0: 100. A modified Hoagland's solution provided all other macronutrients and micronutrients. Root length, root number, shoot color, and shoot quality data were collected weekly for 12 months. The 100% nitrate treatment resulted in 30% more roots during the fall compared to the 100% ammonium treatment The 100% ammonium treatment had 26% greater root length in the spring compared to the two highest nitrate treatments. The 50: 50 treatment produced greater root length during the spring and summer compared to the high nitrate treatments (0: 100 and 25: 75) and at least 30% greater root number during the summer compared to all treatments. All treatments resulted in a decrease in root length for the summer compared to the spring. The 50: 50 treatment provided higher ratings for shoot color for each season and higher quality ratings for the winter and spring. A fertilizer program that contains a portion of its nitrogen as nitrate would be more beneficial certain times of the year than one containing ammonium or nitrate alone.  相似文献   

14.
Plant requires nitrogen for the growth, and it use nitrate and ammonium from the environment. Plant suffers from the toxicity when excess ammonium is supplied as a sole nitrogen, although it could be a good nitrogen source for plant growth. We hypothesized that the different responses of ecotypes to ammonium nutrient could partly account for the adaptation of Arabidopsis to an ammonium environment. The purpose of this study is to understand the different responses of ecotypes in ammonium environment. The growth of Arabidopsis thaliana ecotypes, Columbia was compared to those of Arabidopsis thaliana ecotypes, Landsberg erecta in ammonium nutrient. The ratio of shoot dry weight to root dry weight was compared to evaluate the adaptation of two ecotypes. The shoot:root ratio of Landsberg was significantly higher than that of Columbia. T-DNA insertion in cytosolic glutamine synthetase 1;2, one of the essential ammonium assimilatory enzymes, led a decrease of shoot:root ratio. We also measured the isotope-labeled ammonium uptake and the expression levels of ammonium transporter genes, and also the expression of ammonium assimilatory genes, glutamine synthetase genes and glutamate synthase genes, in roots after ammonium re-supply using real-time polymerase chain reaction analysis. We found that (1) ammonium uptake of Landsberg erecta was higher than that of Columbia, when ammonium was supplied at higher concentration, and (2) cytosolic glutamine synthetase 1;2 was highly increased by ammonium supply in the root of Landsberg erecta. The present study suggested the importance of these two factors for adaptation of Arabidopsis to an ammonium-rich environment.  相似文献   

15.
《Journal of plant nutrition》2013,36(7):1345-1353
Abstract

A three‐year field study was conducted to evaluate cotton (Gossypium hirsutum L.) response to the source and timing of nitrogen (N) on an irrigated coastal plain soil (Lucy loamy sand; Arenic Kandiudults) in south Alabama. Cotton acreage in this region has increased in the past ten years and there was a need for current data describing cotton response to N fertilization. Treatments included N sources, timing of N application (ammonium nitrate), split applications of N (ammonium nitrate and ammonium sulfate), and a no‐N check. Nitrogen sources applied preplant included: (i) ammonium nitrate (34‐0‐0); (ii) ammonium sulfate (21‐0‐0‐24.2); (iii) urea (46‐0‐0); (iv) urea–ammonium nitrate solution (UAN; 32‐0‐0); (v) UAN + ammonium thiosulfate (28‐0‐0‐5). Non‐sulfur sources were applied with and without additional sulfur (S). Times of application were preplant, first true leaf, first square, and first bloom. Two treatments received split applications of N as a 50:50 mixture of ammonium sulfate with urea or ammonium nitrate. Supplemental applications of potassium (K) were evaluated by applying ammonium sulfate in combination with 56 kg K/ha. Yield data showed some minor differences among sources, but overall the results of this three‐year study show that there were no superior N sources. For ammonium nitrate, preplant applications of N were sufficient in two out of three years. Split applications of ammonium nitrate did not improve yields as compared to preplant N. Applying ammonium sulfate with supplemental K or as a 50:50 mixture with ammonium nitrate or urea did not improve yields as compared to ammonium sulfate or ammonium nitrate applied alone. Lint quality was not affected by N fertility treatments.  相似文献   

16.
为系统研究硝态氮、铵态氮及二者不同配施比例对土壤养分供应与水稻生长情况的影响,通过田间小区试验,在相同施氮量条件下,研究了单施硝态氮(N),单施铵态氮(A),硝态氮、铵态氮按1:3(N1A3)、2:2(N2A2)、3:1(N3A1)比例配施对水稻产量、田间养分和氮素利用率的影响,并与农民习惯性施肥方式(U)作比较。研究结果表明:整个生育期内铵态氮对水稻的生长都起着主要作用,铵态氮通过提高水稻氮素利用率和促进水稻有效分蘖的方式提高了水稻产量。随着铵态氮的配施比例由25% 提高到75%,水稻的产量提高了35.18%、氮素利用率提高了46.67%,每公顷产生的经济收益增加了6 820.15元。A处理土壤中硝态氮、铵态氮和碱解氮的含量较N处理显著增加36.41%、30.30% 和8.42%,水稻产量提高了60.11%,氮素利用率提高了171.31%,有效穗数增加了52.31%,相较农民习惯性施肥,单施铵态氮处理每公顷还能增收522.91元。在0 ~ 180 kg/hm2的施氮量范围内,水稻产量(y)与铵态氮施用量(x2)呈显著正相关,二者之间关系为y = 18.044x2 + 4943.4(R2 = 0.975 3)。  相似文献   

17.
WANG Chao  WANG Pei-Fang 《土壤圈》2008,18(5):628-637
The infiltration of water contaminants into soil and groundwater systems can greatly affect the quality of groundwater. A laboratory-designed large soil tank with periodic and continuous infiltration models, respectively, was used to simulate the migration of the contaminants NH4 and NO3 in a soil and groundwater system, including unsaturated and saturated zones. The unsaturated soil zone had a significant effect on removing NH4 and NO3 infiltrated from the surface water. The patterns of breakthrough curves of NH4 and NO3 in the unsaturated zone were related to the infiltration time. A short infiltration time resulted in a single sharp peak in the breakthrough curve, while a long infiltration time led to a plateau curve. When NH4 and NO3 migrated from the unsaturated zone to the saturated zone, an interracial retardation was formed, resulting in an increased contaminant concentration on the interface. Under the influence of horizontal groundwater movement, the infiltrated contaminants formed a contamination-prone area downstream. As the contaminants migrated downstream, their concentrations were significantly reduced. Under the same infiltration concentration, the concentration of NO3 was greater than that of NH4 at every corresponding cross-section in the soil and groundwater tank, suggesting that the removal efficiency of NH4 was greater than that of NO3 in the soil and groundwater system.  相似文献   

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