共查询到19条相似文献，搜索用时 156 毫秒
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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。 相似文献
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H2S作为新型气体信号分子在调控植物生长发育和抗逆境胁迫中发挥着重要作用。为探究外源H2S对盐胁迫下红砂(Reaumuria soongorica)氮代谢的影响机制及最佳叶施浓度,以当年生红砂幼苗为材料,采用盆栽试验,以1/2 Hoagland浇灌为对照(CK)考察在300 mmol·L-1NaCl胁迫(CK300)下,叶面喷施不同浓度(0、0.010、0.025、0.050、0.100、0.250、0.500、1 mmol·L-1)H2S供体硫氢化钠(NaHS)对红砂叶片和根系中硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸合成酶(GOGAT)活性以及硝态氮、可溶性蛋白和游离氨基酸含量的影响。结果表明,盐胁迫下,红砂幼苗根、叶中可溶性蛋白、游离氨基酸、硝态氮含量以及NR、GOGAT、GS活性均较对照(CK)显著下降。经不同浓度外源H2S处理后,红砂根、叶中可溶性蛋白含量与单独盐胁迫对照(CK300)相比显著降低,NR、GOGAT、GS活性和硝态氮、游... 相似文献
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氮素形态对小麦生长中后期保护酶等生理特性的影响 总被引：26，自引：2，他引：26
在水培条件下,探究了氮素形态对小麦营养生殖并进生长时期保护酶的影响。结果表明:铵、硝态氮单供和混合供应对小麦保护酶活性影响不同。在铵、硝态氮混合供应下,叶片SOD、CAT,根系SOD活性最高,同时叶片、根系可溶性蛋白含量最大,根系活力和根系表面K3Fe(CN)6还原活性最高,但MDA含量最高;单供硝态氮时叶片POD活性最高,根系MDA含量最高;单供铵态氮时根系POD、CAT活性最高。单供尿素时叶片仅CAT活性高于铵和硝态氮混合供给,但同时叶片MDA含量也高于铵和硝态氮混合供给。叶片以SOD、CAT和POD为主清除自由基,而根系以SOD和POD为主清除自由基。铵和硝态氮混合供给下,小麦成熟后,地上部干重,籽粒产量最大,根冠比最小。 相似文献
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Ce（Ⅲ）对UV-B辐射胁迫下大豆幼苗N、P含量的影响 总被引：1，自引：0，他引：1
在温室模拟UV-B胁迫下,采用水培法研究稀土Ce(Ⅲ)对大豆(Glycine max)幼苗N、P吸收以及N代谢相关酶活性的影响.结果显示:UV-B辐射胁迫下,大豆幼苗叶片硝酸还原酶 (Nitrate reductase,NR)活性、硝态氮含量、磷含量较对照组均有显著下降,说明UV-B辐射严重抑制NR活性、使叶片内硝态氮(NO-3)和磷含量减少,而且高强度、长时间辐射时的抑制作用更大;而适宜浓度CeCl3(20mg*L-1)处理能提高叶片中NO-3和磷含量,缓解T1、T2胁迫下NO-3和磷含量的减少. 相似文献
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研究不同氮素形态对茅苍术光合特性和氮素吸收的影响,为其栽培氮肥高效利用提供理论依据。以一年生茅苍术为材料,研究不施氮肥、施用硝态氮、铵态氮和酰胺态氮对茅苍术叶片光响应曲线和光合氮素利用效率的影响。结果表明,施用氮肥可不同程度改善叶片光合特性,其中硝态氮处理的叶绿素含量、表观光量子效率、最大净光合速率,光饱和点、净光合速率、气孔导度、蒸腾速率均最高,但其光补偿点和胞间二氧化碳浓度显著低于铵态氮和酰胺态氮处理。同时,硝态氮处理能显著增大叶面积、降低比叶重,促进植株生长,使得其整株生物量比铵态氮和酰胺态氮处理提高6.89%和17.05%。此外,硝态氮处理还增加叶片氮素含量,提高光合氮素利用效率,分别比铵态氮和酰胺态氮处理提高2.43%和6.76%。可见,茅苍术光合特性对硝态氮更敏感,施用硝态氮肥能改善光能特性,促进氮素高效利用。 相似文献
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不同品种菠菜叶柄和叶片的硝态氮含量及其与植株生长的关系 总被引：8，自引：3，他引：8
温室盆栽试验研究了我国北方不同菠菜品种叶柄和叶片的硝态氮含量及其与植株生长的关系。结果表明,30个菠菜品种地上部分的生长量和硝态氮含量存在显著差异。叶柄和叶片在反映品种间生长量和硝态氮含量变异方面的作用并不相同。叶片占植株地上部鲜重的比例高于叶柄,品种间叶片生长量的差异亦大于叶柄,叶片与植株生长量的正相关关系更为显著。但与生长量的情况不同,叶柄的硝态氮含量、累积总量均显著高于叶片,是菠菜累积硝态氮的主要器官。叶柄硝态氮含量的品种间差异远大于叶片,与植株地上部硝态氮含量的正相关性更为显著。菠菜不同品种之间,叶柄硝态氮含量与地上部鲜重、干重及水分均表现出显著的正相关关系,而叶片硝态氮含量与植株生物量及其各组分之间却无这种关系。 相似文献
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通过室内培养,研究了不同亚硝态氮浓度对铜绿微囊藻（Microcystis aeruginosa）生长的影响和藻对亚硝态氮的利用,实验分析了水体中亚硝态氮、硝态氮和铵态氮浓度的变化,测定了铜绿微囊藻的生长曲线、藻细胞内亚硝态氮含量和藻亚硝酸氧化酶（NOR）。结果显示,在10mgNO^-2-N·L^-1的处理组中,培养基中亚硝态氮和硝态氮浓度同时减少,说明铜绿微囊藻可以同时利用亚硝态氮和硝态氮;在20和30mgNO^-2-N·L^-1的处理组中,随着藻的生长培养基中亚硝态氮的浓度减少,硝态氮浓度增加,而且电泳实验显示此培养条件下铜绿微囊藻能产生亚硝酸氧化酶,表明培养基中的亚硝态氮被亚硝酸氧化酶氧化为硝态氮。本实验也表明高浓度的亚硝态氮（大于10mgNO^-2-N·L^-1）能够抑制藻的生长。 相似文献
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不同氮素形态及其比例对菘蓝生物学特性的影响 总被引：3，自引：0，他引：3
采用砂培法栽培菘蓝,以菘蓝叶与根的干重、 主根长度与直径、 叶绿素含量和光合参数为指标,研究三种氮素形态,即硝态氮（NO-3-N）、 铵态氮（NH+4-N）和酰胺态氮［CO(NH2)2-N］四种不同浓度对菘蓝生物学性质的影响,为菘蓝栽培生产中高效利用氮肥提供理论依据。结果表明,氮素处理能增加菘蓝叶与根的干重,铵态氮对菘蓝主根长度及侧根数的影响最显著,而酰胺态氮与硝态氮对主根直径的影响相近,硝态氮对菘蓝的叶干重、 根干重与根冠比的影响最为显著;不同形态氮素处理能显著提高叶绿素含量与净光合速率,硝态氮对叶绿素和净光合速率有显著影响,酰胺态氮对气孔导度与蒸腾速率的影响最显著,铵态氮对叶片的胞间二氧化碳浓度有显著影响。不同形态氮素通过对菘蓝叶片的叶绿素含量和光合参数的影响实现对其生长状况的影响,其中硝态氮对菘蓝生长的影响最为显著。 相似文献
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氮素对不同大豆品种根系分泌物中有机酸的影响 总被引：4，自引：0，他引：4
采用室内溶液培养方法,分别研究了接种根瘤菌处理下,两种氮源和两种氮浓度对两个大豆品种根系分泌物中有机酸的影响。结果表明,合丰25号根系分泌的有机酸种类和数量无论苗期或花期,接种或不接种根瘤菌,均表现为硝态氮处理高于酰胺态氮处理,表明合丰25号大豆更喜硝态氮,硝态氮促进了有机酸的分泌。绥农10号在酰胺态氮下的有机酸种类和数量均高于硝态氮处理,表明其更喜酰胺态氮,酰胺态氮下根瘤菌的存在增加其根系分泌物中有机酸种类和数量。可见,大豆根系分泌物中有机酸的种类和数量因品种而异,因品种对氮源的喜好而变化;根瘤菌在不同程度上增强或减弱根系有机酸的分泌作用。柠檬酸受氮素供应浓度影响很大,当氮素供应浓度较低时,大豆根系分泌物中可检测到柠檬酸,供氮浓度升高则检测不到。 相似文献
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对竹子硝酸还原酶活力的研究表明:因竹叶提取液偏酸,用 pH8.5的25mmol/L 磷酸盐缓冲液(含聚乙烯吡略啉酮(PVP)65mg/ml),提取(最终 pH为7.5)的叶片酶活力最高,酶反应达最高速率时的底物 KNO_3浓度为25mmol/L。在漫射光下,用 50mmol/LKNO_3诱导6h,叶片酶活力达高峰。光照对竹子酶活力具诱导作用,其中以光强5000lx 诱导12h、8000lx 诱导8h 最佳。中龄叶对 KNO_3和光照的诱导反应最敏感,诱导产生的酶活力比嫩叶和老叶高,尚未展开的嫩叶酶活力极低。不同叶龄叶酶活力,与叶片氨基氮和叶绿素含量呈极显著的正相关。在竹根中未能检测出硝酸还原酶活力。 相似文献
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C.F. Alcaraz F. Martínez‐Sánchez F. Sevilla E. Hellln 《Journal of plant nutrition》2013,36(11):1405-1413
The relationship between nitrate reductase activity and ferredoxin levels in lemon tree leaves was studied. The experiments were carried out on leaves from full‐nutrient sufficient trees as the reference, and on leaves from trees with several nutritional stresses, mainly iron chlorosis from trees growing under Fe‐stressed conditions.
Iron deficiency reduced leaf ferredoxin concentration and consequently decreased nitrate reductase activity. Fe(II) infiltration treatments of intact leaves, as well as several incubation assays, permit to deduce the dependence of the enzymatic nitrate reduction of the leaf ferredoxin levels. 相似文献
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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. 相似文献
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Giuseppe Colla Youssef Rouphael Cristina Mirabelli Mariateresa Cardarelli 《植物养料与土壤学杂志》2011,174(6):933-941
Two experiments were conducted to study the effect of grafting on nitrogen‐use efficiency (NUE) in mini‐watermelon plants. In the first study, mini‐watermelon plants (Citrullus lanatus [Thumb.] Matsum. and Nakai cv. Minirossa) either ungrafted or grafted onto Macis, Vita (Lagenaria siceraria [Mol.] Standl.), PS1313, and RP15 (Cucurbita maxima Duchesne × Cucurbita moschata Duchesne) rootstocks grown in hydroponics were compared in terms of shoot dry biomass, leaf area, root‐to‐shoot ratio, SPAD index, shoot N uptake, and nitrate reductase (NR) activity 40 d after transplantation in response to nitrate concentration in the nutrient solution (0.5, 2.5, 5, 10, 15, or 20 mM of NO$ _3^- $ ). In the second experiment, the suitability of a selected rootstock with high NUE (Vita) to improve crop performance and NUE of grafted mini‐watermelon plants was evaluated under field conditions. In the hydroponic experiment mini‐watermelon grafted onto Vita rootstock needed the lowest nitrate concentration (1.31 mM of NO3) in the nutrient solution to reach half maximum shoot dry weight. Total leaf area, SPAD index, and shoot N uptake increased in response to an increase of N concentration in the nutrient solution. At 2.5 mM NO$ _3^- $ , mini‐watermelon grafted on either Vita or RP15 had the highest NR activity whereas no significant difference was observed at 10 mM NO$ _3^- $ . The open‐field study indicated that increasing N‐fertilization rates from 0 to 100 kg ha–1 improved total and marketable yields of mini‐watermelon plants while decreasing NUE. When averaged over N levels, the marketable yield, NUE, N‐uptake efficiency, and N‐utilization efficiency were significantly higher by 39%, 38%, 21%, and 17%, respectively, in Minirossa grafted onto Vita compared to ungrafted Minirossa plants. Therefore, grafting mini‐watermelon plants onto selected rootstocks can be used as a quick and effective method for improving productivity and NUE. 相似文献
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Mir Hatam 《Soil Science and Plant Nutrition》2013,59(3):315-318
Nitrate reductase (NR) activities of soybeans (Glycine max L. Merr. Cv. Altona), grown in sand with nutrient solution containing only nitrate as a nitrogen (N) source, were compared, using one in vivo and two in vitro assays. The in vivo assay was the most sensitive of the three, particularly in measuring root NR activity. NR activity was highest in the upper most expanded leaf and declined with leaf position lower in the canopy. NR activity in the lower 6 em sections of roots was more than double that of the upper 6 cm sections. Differences in NR activity at different stem positions were not detected by the three techniques. 相似文献
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试验采用裂区设计,以硝态氮和铵态氮两种氮素形态为主处理,5个供氮水平为副处理,在大田条件下研究了水田与旱地烤烟在团棵、旺长、脚叶采烤、腰叶采烤和顶叶采烤等5个生育期烟叶的总氮浓度、硝酸还原酶和谷酰胺合成酶活性的氮肥效应。结果表明,水田与旱地烤烟在各氮肥处理下团棵期烟叶的氮浓度最高,旺长期稍有下降,至脚叶采烤期则迅速降低;烟叶中的硝酸还原酶和谷酰胺合成酶活性从团棵到旺长期迅速升高,进入采烤后逐渐降低。水田烤烟烟叶总氮浓度和硝酸还原酶活性比旱地烤烟大,而谷酰胺合成酶则水田小于旱地,说明烤烟在水田状况下吸氮能力比旱地烤烟强;然而水田烤烟氮同化能力比旱地烤烟弱。试验结果还表明,水田与旱地烤烟烟叶的总氮浓度、硝酸还原酶和谷酰胺合成酶活性分别在09～0.kg/hm2和07～5.kg/hm2范围内随施氮量的增加而提高;由于土壤中铵态氮的转化与硝态氮淋溶损失,导致铵态氮的肥效优于硝态氮。 相似文献
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Differences in nitrogen‐assimilating enzyme activity in halophyte species are habitat‐related 
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下载免费PDF全文 The chemical form and content of available nitrogen (N) in salt marsh substrates varies considerably. On the western coast of Ireland, habitats designated as Ombrogenic Atlantic salt marshes were formed on ombrogenic peat substrate. The peat substrate in these systems has three times more ammonium than substrate from adjacent salt marsh habitats on sand and mud substrate. This study examined the extent to which the high concentration of ammonium in peat salt marsh substrate influences the N‐ assimilating enzyme activity of halophytes and the extent to which N metabolism differs between species. Specifically, this work investigated whether plants from peat salt marshes are more likely to assimilate ammonium than plants from non‐peat substrates. Four halophyte plant species—Armeria maritima, Aster tripolium, Plantago maritime, and Triglochin maritime—were sampled from various saltmarsh habitats including three sites on peat substrate and three on non‐peat substrate, comprising sand, mud and sand/mud. The activities of N‐metabolising enzymes—glutamine synthetase (GS), glutamate synthase, glutamate dehydrogenase (GDH), and nitrate reductase (NR)—were quantified in shoot and root parts. Root GS activity in Armeria maritima and shoot GS activity in Triglochin maritima were positively correlated with increasing soil ammonium levels. Root NR activity in Aster tripolium and shoot NR activity in Plantago maritima were significantly higher in plants grown on non‐peat substrates than peat substrates. The shoot : root GS activity ratio in Triglochin maritima on peat substrate was more than double the ratio on non‐peat substrates. It is concluded that all species tested displayed differences in N‐metabolising activities depending on the chemical form and/or concentration of N in the substrate, while three out of the four species were capable of taking advantage of the high levels of ammonium in peat substrates. 相似文献
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玉米硝酸盐累积及其在适应持续低氮胁迫中的作用 总被引：3，自引：1，他引：2
旱地作物吸收氮素的主要形态是硝酸盐,硝酸盐的积累与再利用对植物适应低氮土壤环境具有重要意义。本试验利用两个硝酸盐累积能力不同的玉米自交系478（硝酸盐积累低）和W312（硝酸盐积累高）为研究材料,研究玉米的硝酸盐累积及其在适应持续低氮胁迫中的作用。结果表明,W312的硝酸还原酶活性和NR基因的表达都弱于478,而体内氨基酸含量显著较低。对一个可能与液泡膜硝酸盐转运有关的氯离子通道蛋白基因（ZmCLC）的表达分析发现,478的ZmCLC表达显著强于W312。说明W312硝酸盐积累能力强主要是由于其较弱的氮同化能力,而不是硝酸盐向液泡的运输能力强。在砂培体系并持续缺氮条件下,W312叶绿素含量（SPAD值）显著高于478,表明植株体内较高硝酸盐累积有助于W312适应持续缺氮的土壤环境。 相似文献