硝酸还原酶基因启动子NRE2元件缺失对烟草氮代谢的影响

为了探究硝酸还原酶基因启动子中硝酸盐响应元件NRE2缺失对烟草植株氮代谢的影响,以烤烟品种K326为材料,采用CRISPR/Cas9基因编辑技术获得了烟草NIA11和NIA2基因启动子中NRE2元件缺失的突变体材料,并于同一氮素营养条件下培养,测定烟草植株氮代谢相关生理指标.结果表明,与野生型相比,单突变体和双突变体叶...     

施肥对土壤及黄瓜中稳定性氮同位素丰度的影响

研究不同肥料配施对土壤、黄瓜及其叶片中稳定性氮同位素丰度(1δ5N‰)及硝酸盐和硝酸还原酶活性的影响。结果表明,随着配施有机肥比例的降低,黄瓜中1δ5N呈现先低后高再低的趋势;各处理单施化肥初期时黄瓜中1δ5N与有机肥60%和40%配施处理间差异显著(P0.05),中期时与有机肥60%、40%配施处理及对照间的差异显著(P0.05),末期时与有机肥60%配施处理间有差异(P0.05),与其他不同配施时差异不显著(P0.05);相同处理的不同采摘时期黄瓜中1δ5N差异不显著(P0.05)。不同处理时叶片与黄瓜间的1δ5N呈正相关(r=0.9836),其1δ5N主要受不同肥料配施处理的影响。随着有机肥比例的降低,黄瓜中硝酸盐含量逐渐降低,与黄瓜中1δ5N间的线性相关性差(r=0.6568);而叶片中硝酸还原酶活性逐渐提高,其中对照处理、100%、80%和60%有机肥处理时与叶片中δ15N丰度呈正相关(r=0.9187);60%、40%、20%有机肥和100%化肥处理时与叶片中1δ5N呈负相关(r=-0.9773)。总体来看,可以初步利用1δ5N作为标记来区分有机肥和化肥种植的黄瓜,但需要进一步研究1δ5N在作物中的分馏和分布规律。     

不同氮素水平对甜菜硝酸还原酶和亚硝酸还原酶活性的影响

以当前甜菜（Beta Vulgaris L.）生产主栽品种KWS0143为试材,设立4个氮素水平（N 0、60、120、180 kg/hm2）,研究硝态氮肥对甜菜硝酸还原酶（nitrate reductase, NR）和亚硝酸还原酶（nitrite reductase, NiR）活性以及光合速率与叶绿素总含量的影响,探讨了氮素水平与NR及NiRA之间的关系。结果表明:在甜菜生育期间,光合速率呈单峰曲线变化,NR、NiR活性及叶绿素总含量基本呈双峰曲线变化,叶绿素变化曲线的高峰期早于NR活性,NR活性早于NiR活性。氮肥用量在N 120 kg/hm2时显著提高了甜菜光合速率、叶绿素总含量、NR活性和NiR活性。相比于N 120 kg/hm2,N 180 kg/hm2时光合速率及叶绿素总含量没有明显变化,NR与NiR活性则有一定的提高。本试验中,甜菜产量随氮水平的增加而提高;含糖率则相反,随氮水平的增加而降低,N 120 kg/hm2水平下产糖量最高。     

水分胁迫下氮素对分蘖期小麦某些生理特性的影响

本研究结果表明 :水分胁迫且充足供氮时 ,叶片硝酸还原酶活性降幅较小 ;水分胁迫且不供氮时 ,硝酸还原酶活性几乎检测不出。水分胁迫下叶片可溶性蛋白含量和叶绿素含量均低于对照 ;根系活力在水分胁迫下均升高 ,根系还原活性在水分胁迫下显著降低。在小麦分蘖期 ,水分胁迫使根系的分布范围增大 ;氮素供给充足时 ,水分胁迫使根系干物质积累增多 ;但水分胁迫下使地上干物质积累降低 ,不供氮处理降幅更大。分蘖期的水分胁迫导致小麦收获期株高显著低于对照处理 ,不供氮处理更是明显 ;根系、地上干物质积累低于对照水平 ;不供氮处理降幅极大。分蘖期水分胁迫处理影响小麦的产量     

Nitrate nitrogen and nitrate reductase activity in Verna lemon tree leaves

The determination of the leaf nitrate concentration, as well as the nitrate reductase activity have been proposed as a parameters for the estimation of the nitrogen requirements of citrus plants. Because this, it is interesting to dispose of a well criteria for their suitable diagnosing. On nutritionally normal Verna lemon trees we study the annual evolution of the leaf nitrate levels as well as the nitrate reductase activities. At the same time, the cause of the nitrogen alterations induced by iron chlorosis are determined. The results show that is the ferredoxin the iron compound responsible of this nitrogen unbalance.     

Lime,molybdenum, and cultivar effects on molybdenum deficiency of poinsettia

Poinsettia (Euphorbia pulcherrima Willd. ex Klotz) cultivars ‘Annette Hegg Brilliant Diamond’ (AH), ‘Gutbier V‐14 Glory’ (GG), and ‘Eckespoint C‐1 Red’ (ER) were grown in a peat‐perlite potting medium to study lime and Mo effects on the occurrence of Mo deficiency. Two rates of dolomitic limestone, 0 and 3 kg/m³of growing medium, and weekly applications of micronutrient solutions containing 0.0 or 1.0 ppm Mo were made in factorial combination. Lime, Mo, or both prevented Mo deficiency symptoms in all cultivars. Without both lime and Mo, Mo deficiency symptoms appeared on AH and GG, but not on ER. Lime and/or Mo reduced NO₃‐N content, increased Mo content and increased nitrate reductase enzyme activity (NRA) in the upper recently matured leaves of all cultivars. Lime and Mo interacted to affect these parameters in all cultivars. Comparing the three cultivars without both lime and Mo, NO‐‐N content was lowest and NRA highest in ER. However, the Mo content of ER leaves was equal to or less than that of AG and GG which showed Mo deficiency symptoms.     

大豆硝酸还原酶活性及其与施氮关系的研究

以绥农14为材料,利用框栽、砂培和15 N标记的方法,研究了大豆硝酸还原酶（NR）活性及其与施氮水平的关系。结果表明：框栽试验中大豆叶片NR活性随生育进程的推进大体上呈单峰曲线变化,营养生长阶段叶片NR活性较低,进入生殖生长期后逐渐升高,并于盛花期前后达到峰值,随后呈逐渐下降趋势;施氮水平对NR活性有明显影响,营养生长...     

水稻土裂缝的演变及其还原酶活性的变化研究

在温室中对3种水稻土进行土柱培养,加水使土壤含水量充分饱和,然后土壤自然干燥。在该过程中,粘粒含量高的青紫泥和黄斑田产生了裂缝,而粘粒含量低的小粉土没有开裂。青紫泥和黄斑田在裂缝演变过程中,单位面积的总长度、最大宽度以及最大深度都遵循着一定的演变规律。裂缝的产生对于硝酸还原酶和羟胺还原酶活性的变化影响显著,但是亚硝酸还原酶活性的变化与裂缝的产生没有多大关系。在裂缝产生到稳定过程中,青紫泥和黄斑田的硝酸还原酶、亚硝酸还原酶和羟胺还原酶活性的演变规律相似。     

How Does Nitrogen Application Ameliorate Negative Effects of Long-Term Drought in Two Maize Cultivars in Relation to Plant Growth,Water Status,and Nitrogen Metabolism?

Two maize cultivars, Shaandan 9 (S₉) and Shaandan 911 (S₉₁₁), were investigated to explore the ameliorating effects of nitrogen (N) addition on their growth, water status, and N metabolism under long-term drought stress (DS). Elevated N rate increased dry matter, grain yield, relative water content, nitrate reductase activity, soluble protein concentration, and concentrations of free proline and endogenous glycinebetaine (main contributors to osmoregulation) of both cultivars under DS than control. The responses under DS were more significant for S₉₁₁ than those for S₉, especially at high N rate. Additionally, S₉ maintained greater evaluated parameters than S₉₁₁ with no N addition under DS, and these differences decreased with N application. Correlations were more evident among all parameters under DS than those under control. Thus, moderate N plays an evident physiological role in alleviation of DS effects on plant growth by improving water status and N metabolism, especially for drought-sensitive cultivars.     

Effect of Foliar Nitrogen Application on Nitrogen Metabolism,Water Status,and Plant Growth in Two Maize Cultivars under Short-term Moderate Stress

Two contrasting maize (Zea mays L.) cultivars, i.e. ‘Shaandan 9’ (S₉) and ‘Shaandan 911’(S₉₁₁) were investigated by examining foliar nitrogen (N) modulation of N metabolism, water status and plant growth under short-term moderate water stress (SMWS). On 10th day of SMWS, dry matter (DM), relative water content (RWC) and nitrate reductase activity (NRA) were significantly decreased, whereas concentrations of free proline (FP), glycinebetaine (GB) and soluble protein (SP) were increased in leaves of both cultivars. Cultivar S₉ maintained greater DM, RWC and these N metabolism traits than S₉₁₁ during SMWS. Foliar N application much more raised DM, RWC, NRA, and concentrations of all solutes measured under SMWS above control. These positive effects were more pronounced in S₉₁₁ than those in S₉ during SMWS. Greater correlations were performed amongst all parameters under SMWS than control. Hence, we suggest that foliar N should be firstly applied to drought sensitive cultivars under drought.     

Contribution of dissolved organic nitrogen to N leaching from four German agricultural soils

Dissolved organic nitrogen (DON) substantially contributes to N leaching from forest ecosystems. However, little is known about the role of DON for N leaching from agricultural soils. Therefore, the aim of our study was to quantify the contribution of DON to total N leaching from four agricultural soils. Concentrations and fluxes of DON and mineral N were monitored at two cropped sites (Plaggic Anthrosols) and two fallow plots (Plaggic Anthrosol and Gleyic Podzol) from November 1999 till May 2001 by means of glass suction plates. The experimental sites were located near the city of Münster, NW Germany. Median DON concentrations in 90 cm depth were 2.3 mg l^—1 and 2.0 mg l^—1 at the cropped sites and 1.6 mg l^—1 and 1.3 mg l^—1 at the fallow sites. There was only a slight (Anthrosols) or no (Gleyic Podzol) decrease in median DON concentrations with increasing depth. Total N seepage was between 19 kg N ha^—1 yr^—1 and 46 kg N ha^—1 yr^—1 at the fallow sites and 16—159 kg N ha^—1 yr^—1 at the cropped sites. For the fallow plots, DON seepage contributed 10—21 % to the total N flux (4—5 kg DON ha^—1 yr^—1), at the cropped sites DON seepage was 6—21 % of the total N flux (6—10 kg DON ha^—1 yr^—1). Thus, even in highly fertilized agricultural soils, DON is a considerable N carrier in seepage that should be considered in detailed soil N budgets.     

新型生物炭基氮肥对土壤一冬小麦系统氮素累积及相关生物活性的影响

通过田间试验,研究了掺混型、吸附型和反应型3种新型生物炭基硝酸铵氮肥在冬小麦生长过程中对土壤氮素累积及冬小麦对氮素的利用状况和相关生物活性的影响。试验处理包括CK（不施氮肥,不施生物炭）、硝酸铵氮肥、生物炭、掺混型生物炭基氮肥、吸附型及反应型生物炭基氮肥。研究结果表明：不同工艺制备的生物炭基氮肥对土壤铵态氮的累积具有显著影响,吸附型和反应型处理在冬小麦生长季铵态氮平均值大于对照（CK）,对于总氮、硝态氮和亚硝态氮累积量的影响不显著。除了生物炭单施处理外,其他处理均比CK显著提高冬小麦地上部的总氮累积量,但对冬小麦的氮素利用状况无显著影响,且三种炭基氮肥处理问无显著差异;施用不同类型生物炭基氮肥对土壤微生物量氮含量和硝酸还原酶活性具有提高作用,而对微生物量碳含量、亚硝酸还原酶和脲酶活性无显著影响。     

两个品种水稻中硝酸盐吸收和利用率对氮素饥饿的响应特征

Ammonium（NH＋4） is the main nitrogen（N） form for rice crops, while NH＋4near the root surface can be oxidized to nitrate（NO-3）by NH＋4-oxidizing bacteria. Nitrate can be accumulated within rice tissues and reused when N supply is insufficient. We compared the remobilization of NO-3stored in the tissue and vacuolar between two rice（Oryza sativa L.） cultivars, Yangdao 6（YD6, indica）with a high N use efficiency（NUE） and Wuyujing 3（WYJ3, japonica） with a low NUE and measured the uptake of NO-3, expression of nitrate reductase（NR）, NO-3transporter genes（NRTs）, and NR activity after 4 d of N starvation following 7-d cultivation in a solution containing 2.86 mmol L-1NO-3. The results showed that both tissue NO-3concentration and vacuolar NO-3activity were higher in YD6 than WYJ3 under N starvation. YD6 showed a 2- to 3-fold higher expression of OsNRT2.1 in roots on the 1st and 4th day of N starvation and had significantly higher values of NO-3uptake（maximum uptake velocity, Vmax） than the cultivar WYJ3.Furthermore, YD6 had significantly higher leaf and root maximum NR activity（NRAmax） and actual NR activity（NRAact） as well as stronger root expression of the two NR genes after the 1st day of N starvation. There were no significant differences in NRAmax and NRAact between the two rice cultivars on the 4th day of N starvation. The results suggested that YD6 had stronger NRA under N starvation, which might result in better NO-3re-utilization from the vacuole, and higher capacity for NO-3uptake and use, potentially explaining the higher NUE of YD6 compared with WYJ3.     

菠菜叶片硝态氮还原对叶柄硝态氮含量的影响

选用3个菠菜品种,设置N.0.1和0.3.g/kg2个施氮水平进行盆栽试验。在不同时期采样测定叶片内、外源硝酸还原酶活性、硝态氮代谢/贮存库大小,以及加入外源硝态氮培养后叶片硝酸还原酶活性的变化,探讨菠菜叶片的硝态氮还原与叶柄硝态氮含量的关系。结果表明,叶片内源硝酸还原酶活性、内源/外源硝酸还原酶活性比值、叶片的硝态氮代谢库大小及代谢/贮存库比值与叶柄硝态氮含量呈相反趋势。加入外源硝态氮培养后叶片硝酸还原酶活性的增加程度与叶柄硝态氮含量相一致。叶片内源硝酸还原酶活性高低及其发挥程度,叶片硝态氮代谢库大小及硝态氮在代谢、贮存库中的分配是造成品种间叶柄硝态氮含量高低差异的重要原因。     

Effects of N‐source,light intensity and temperature on nitrogen metabolism of bahiagrass

Under greenhouse conditions, a study was made on the effects of nitrogen (N) source (N)O₃ or NH₄), mode of application (single vs. split) and nitrification inhibition on the N‐uptake and metabolism, of bahiagrass.

Variations in light and temperature in the greenhouse affected the N‐metabolism of bahiagrass plants. Nitrate fed plants had nitrate reductase activity (NRA) pattern different from that of NH₄‐fed plants. Amino‐N accumulation patterns were similar for plants under both N‐sources, although amino‐N levels in leaves of NH₄‐fed plants were much smaller than that of NO₃ plants. Nitrate accumulation in leaves showed inverse trend to that of roots in plants fed both NO₃ or NH₄. To the sharp peaks in NO₃ levels in roots due to increases in light and temperature corresponds a sharp decrease of its levels in leaves.

For both both NO₃ or NH₄ treatments, soluble‐N accumulated most in the rhizomes of bahiagrass plants, whereas protein N accumulated most in leaves, suggesting that rhizomes had a buffering effect on the NO₃ fluxes to leaves. This presumably resulted in a lag in the NRA response of the NO₃‐fed plants to increases in light and temperature.