傅立叶变换中红外光谱估测水稻叶片氮素含量的研究

通过不同氮素水平的水稻田间试验,在分析测定了水稻叶片叶绿素、氮素等农学参数后,采用傅立叶中红外光谱仪测定了水稻孕穗期叶片干样的透射光谱,利用协同偏最小二乘算法（siPLS）分析选取了傅立叶变换红外光谱估测水稻氮素含量的敏感波段及其组合。结果表明,其最优主成分数是9个,最佳估测建模的波段组合分别为1350.89～1586.57, 1587.53～1822.40 和 3709.41～3943.72 cm-1;建立的水稻氮素预测模型的精度较高,交互验证均方根误差（RMSECV）和预测均方根误差（RMSEP）分别为0.1538和0.1933,预测值与化学分析获得的叶片总氮浓度之间的交互相关系数和独立检验相关系数分别为0.9393和0.6649,高于中红外光谱指数NFS和NFSA的预测精度。说明利用傅立叶红外光谱作为水稻氮含量的诊断技术是可能的,值得进一步验证和完善。     

不同傅里叶变换红外光谱法研究土壤光谱特征的比较与应用

为了将傅里叶变换红外光谱技术更好地应用于土壤中官能团的定量分析,通过比较3种不同傅里叶变换技术下土壤特征吸收峰的差异,来选取最佳的光谱技术应用于土壤的相关研究。采用透射(T-FTIR)、衰减全反射(ATR-FTIR)和漫反射(DR-FTIR)3种光谱技术分别对有机物(苯甲酸、硬脂酸)和土壤(辽东栎)进行了分析。并将辽东栎和草地土壤样品按不同比例混合,使用T-FTIR和DR-FTIR对混合土样进行光谱测定,用于定量分析研究。结果表明:(1)有机物样品在3种光谱技术中均出现特征吸收峰,苯甲酸在1 600～1 400 cm^-1出现苯环C=C骨架特征峰,硬脂酸在2 900～2 800 cm^-1显现甲基的特征峰。有机物中羧酸-COOH内羰基-C=O在1 720～1 680 cm^-1出现伸缩振动吸收峰,羟基-OH分别在1 430～1 410 cm^-1,940～930 cm^-1附近出现面内和面外弯曲振动吸收峰。有机物在T-FTIR技术中需要用溴化钾(KBr)对其稀释。(2)辽东栎土壤样品在T-FTIR和DR-FTIR技术测试中发现,其土壤谱图中有较多有效特征吸收峰,土壤样品在T-FTIR技术中也需要用KBr进行稀释并使样品均匀的分布在锭片中; 而ATR-FTIR技术测试中仅出现个别有效特征吸收峰,不利于对土壤谱图鉴别与进一步分析。(3)辽东栎和草地土壤样品按不同比例混合的测试结果表明:T-FTIR和DR-FTIR技术测试中质量分数与峰面积比呈正相关,线性拟合分别为R²=0.70和R²=0.88。土壤在3种不同红外技术中,DR-FTIR光谱具有较好的土壤特征吸收峰,对土壤样品可以不用KBr稀释。测试步骤简单易操作,可用于土壤样品定量分析研究。     

缺锌与低锌对玉米苗期生长发育的影响

用溶液培养的研究了缺锌,低锌和正常供锌对玉米生长发育的影响。结果表明：缺锌和低锌使玉米的株高和茎叶干重均显著降低,低锌比缺锌降低的更多,缺锌和低锌对根干重的影响远小于对地上部的影响,所以,使根冠比增大,缺锌和低锌对玉米生长发育的这种影响与其影响玉米体内的锌含量有关,而且这种影响因玉米的品种不同而差异。     

黄土的红外反射光谱与红外光声光谱特征及其差异研究

红外光谱法作为一种新的研究手段已经广泛应用于土壤分析,由其检测区域和手段的不同又可分为多种光谱类 型。本研究以第四纪黄土为例,系统地比较了近红外区和中红外区反射光谱和光声光谱的吸收特征及其差异。结果表明,中红外光谱比近红外光谱的信息更为丰富,且中红外光谱与样品中物质的特征吸收关系更加密切,从而更有利于土壤定性与定量分析。土壤的反射光谱和光声光谱表现出了明显不同的特征,在近红外区,反射光谱和光声光谱吸收明显不同,而在中红外区,反射光谱和光声光谱具有相对应的吸收,但相对吸收强度明显不同,且吸收峰的位置也发生改变,尤其在1 000 ~ 2 000 cm-1谱区,反射光谱相互干扰很强,而光声光谱的吸收特征更为明显。在黄土的分类鉴别上,反射光谱优于光声光谱。红外反射光谱和光声光谱在不同波段下具有不同的吸收灵敏度,在土壤定性与定量分析中各自都将具有其明显的优势。     

有机肥腐解过程的红外光谱研究

对玉米秸秆、树叶、鸡粪及牛粪4种有机肥腐解过程中形成的水溶性有机物(WOM)进行了化学分析并做了红外光谱研究。结果表明,不同的有机肥的WOM总量及各组分的含量有很大的差异,树叶和玉米秸秆腐解形成的WOM中,水溶性胡敏酸(WHA)所占的比例较大;而牛粪和鸡粪腐解形成的WOM中,水溶性小分子有机物(WLOM)所占的比例较大。随着有机肥的腐解,所形成的WLOM中,脂肪族化合物、酰胺类化合物逐渐减少,有机酸的比例不断增大。WHA中的甲基、亚甲基和次甲基的含量升高,脂族性增强,酰胺结构成分逐渐减少。树叶腐解形成的碱提胡敏酸(AHA)的脂肪链结构和碳水化合物成分含量较低。牛粪腐解形成的AHA的脂肪链结构成分和碳水化合物成分含量较高。鸡粪腐解形成的AHA缺乏脂肪链结构成分,碳水化合物成分含量较高。而玉米秸秆腐解形成的AHA在不同的腐解时期有一定差异。     

高耐铝红酵母RS1的红外光谱和拉曼光谱研究

微生物菌株RS1是从江西鹰潭油茶酸性土壤中筛选获得的一株高耐铝红酵母,能够忍耐高达200 mmol/L以上的铝浓度。前期研究表明RS1可以把铝固定在细胞表面,阻挡其进入细胞内部,但是细胞表面何种基团参与铝的固定并不清楚。本文综合采用傅里叶红外光谱和拉曼光谱技术研究了铝胁迫下红酵母RS1细胞表面官能团变化,以期从光谱学角度来探索RS1的高耐铝机制。研究发现,70 mmol/L铝处理24 h后RS1红外光谱中1 403 cm^-1处的吸收峰红移到1 397 cm^-1处,这可能是羧基峰;在1 706 cm^-1处出现新的吸收峰,这可能是羰基峰;酰胺I带吸收峰强度显著上升,且甘露聚糖的吸收峰消失。拉曼光谱在779、856 cm^-1处和1270cm^-1处出现新的吸收峰,可能分别为核糖核酸、酪氨酸和酰胺Ш带的吸收峰。综合结果表明,RS1细胞表面与铝吸附相关的物质主要是细胞壁多糖和蛋白质,主要涉及的官能团包括羧基、羰基和酰胺基。这些细胞表面官能团对铝的固定作用可能是红酵母RS1高耐铝的一个重要机...     

红外光谱在土壤学中的应用

红外光谱技术在土壤学中已得到较广泛的应用,它能够综合地反映土壤体系的物质组成及其相互作用,为研究土壤中物质循环及其作用过程提供了新的手段。本文回顾了近年来红外光谱技术在土壤学中的应用,包括透射光谱在土壤定性分析中的应用,并重点介绍红外反射光谱与化学计量学相结合的光谱建模技术发展情况及其在土壤定量分析中的应用。同时本文探讨了基于光声效应的红外光声光谱技术,红外光声光谱非常适合用于土壤这种复杂、非透明体系的研究,能够克服传统透射和反射光谱中存在的缺陷,测定快速方便,并具有较高的灵敏度和测量精确度,具有很大的应用潜力。     

缺锌与低锌对玉米苗期生长发育的影响

用溶液培养的方法研究了缺锌、低锌和正常供锌对玉米生长发育的影响.结果表明:缺锌和低锌使玉米的株高和茎叶干重均显著降低,低锌比缺锌降低的更多;缺锌和低锌对根干重的影响远小于对地上部的影响,所以,使根冠比增大,缺锌和低锌对玉米生长发育的这种影响与其影响玉米体内的锌含量有关,而且这种影响因玉米的品种不同而有差异.     

水稻秸杆腐解过程溶解性有机质红外光谱研究

采用傅里叶红外光谱(FTIR)分析方法研究了水稻秸杆不同腐解阶段产生溶解性有机质(dissolvedorganic matter,DOM)及其分组组分的结构特征.结果表明,水稻秸杆腐解过程中DOM组成成分的变化呈现出明显的阶段性.在第0～3天,秸杆本身含有的糖类、氨基酸等小分子物质因微生物繁殖迅速消失;第3～ 63天,主要是秸杆中的半纤维素、纤维素的分解阶段,DOM组成中多糖类、烷烃类物质呈现起伏性变化;第63天后,主要是腐殖化阶段,DOM分子结构复杂化.各分组组分的结构特征有明显差异,且各组分均随腐解延长而发生变化,即多糖类物质减少,芳香族物质增多,分子结构复杂化.     

不同土壤水分供应下锌对玉米叶片超微结构的影响

选择 土为供试土壤, 进行盆栽玉米试验, 设定0和5.0 mg·kg^-1两个锌处理, 按土壤饱和持水量的40%~45%和70%~75%在玉米的4叶1心期实施干旱和正常水分处理。生长50 d后, 测定不同土壤水分与锌供应状况下植株生物量和锌含量, 利用透射电子显微镜观察完全伸展新叶的超微结构变化, 以期揭示不同土壤水分供应下, 植物对施锌的响应机理。结果表明: 土壤水分供应充足条件下, 与不施锌相比, 施锌玉米地上部生物量和总干重分别增加78%和52%, 根系和地上部锌含量和锌吸收量增加较多; 而干旱条件下, 施锌对玉米生物量无显著影响。干旱条件下缺锌玉米叶片维管束鞘细胞中叶绿体结构基本保持完好, 淀粉粒和基质片层清晰可见, 但叶肉细胞中叶绿体膜受损, 基质片层结构出现皱缩, 基粒片层减少; 施锌玉米叶片维管束鞘细胞中叶绿体结构保持完好, 叶绿体周围的线粒体数目较多, 叶肉细胞中叶绿体中脂肪颗粒增多, 叶片维管束鞘细胞与叶肉细胞之间可见清晰的胞间连丝。土壤水分充足处理下, 缺锌叶片细胞膜出现皱缩, 维管束鞘细胞叶绿体淀粉粒增多, 片层结构受损, 严重时维管束鞘细胞中内溶物消失, 残存的叶绿体中仅有淀粉粒和少许片层; 叶肉细胞中叶绿体可见淀粉粒, 但片层结构少, 有些出现断裂、收缩。土壤水分充足条件下, 施锌玉米维管束鞘核叶肉细胞结构清晰, 叶绿体结构完整。结论认为: 锌对干旱胁迫下玉米叶片细胞结构的破坏有一定的缓解作用; 但土壤水分正常供应下, 缺锌导致细胞结构受损程度比干旱情况下更严重。     

畜禽粪便热解气体的红外光谱分析

为了解畜禽粪便热解过程析出气体的主要成分以及气体析出规律,该文在30℃/min的升温速率条件下进行了猪粪、牛粪、羊粪和鸡粪的热解试验,利用傅里叶变换红外光谱（FTIR）技术对热解过程中气体产物的排放特性进行了分析。试验结果表明,畜禽粪便气体产物主要在250～500℃析出,其主要成分为H2O,CO,CO2和CH4等,其中H2O、CO和CO2的析出峰为双峰,H2O和CO2均在350℃附近形成最大析出峰,H2O约在150℃形成第1个析出峰,CO2约在710℃附近形成的第2个析出峰,CO在350℃处形成第一个析出峰,其最大析出峰形成于710℃处左右,CH4析出特性为一单峰,在530℃附近形成最大峰值。该文研究结果为热解反应器的设计和优化提供参考。     

Correction and standardization of critical limit of zinc for maize (Zea mays L.) crop: Bangladesh perspective

Abstract

Critical limit (CL) determination of zinc (Zn) is very important for predicting response of maize crop to its application in soils and for the crop’s actual fertilizer requirement. This study was conducted at Bangladesh Agricultural Research Institute, Gazipur, to determine the CL of Zn for maize grown in 20 soils collected from the five Agro–Ecological Zones during January to March, and April to June of 2017. The available Zn content of soils and maize biomass were estimated utilizing the extraction method with 0.005?M diethylene triamine pentaacetic acid (DTPA). During January to March and April to June 2017, the amount of DTPA extractable Zn in different soils ranged from 0.60–3.25?mg?kg^?1 and 0.50–1.68?mg?kg^?1, respectively. During both periods of crop growth (January to March and April to June, 2017), the soil available zinc was negatively significantly correlated with soil pH, available P, exchangeable Ca, exchangeable Mg and positively significantly correlated with relative dry matter (DM) yield. Soil Zn also positively significantly correlated with maize tissue Zn content (r?=?0.521*). However, the CL of Zn were estimated to be 0.84?mg kg^?1 in soils and 26.1?mg kg^?1 in maize tissue for maize cropping as determined by Cate and Nelson’s (1965 Cate, R. B., and L. A. Nelson. 1965. A rapid method for correlation of soil test analysis with plant response data. International soil testing series technical Bulletin No. I North Caroline State University, Agricultural Experiment Statistics, Releigh, USA, pp. 135–136. [Google Scholar]) graphical procedure. Maize crop may respond to Zn application in soils containing Zn at/below the above level. This data may be used for predicting plant response to Zn fertilizer and development of crop Zn nutrition guide for maximum production.     

Denitrification with and without maize plants (Zea mays L.) under irrigated field conditions

The study was conducted under irrigated field conditions to examine the effect of maize plants on denitrification. Both planted and unplanted field plots received 150kgNha^–1 as urea. In a third treatment, which was also planted and received urea at 150kgNha^–1, the soil nitrate N content was brought up to equal to that in the unplanted plots by applying additional doses of N as calcium nitrate. Soil cores were collected 24 and 72h after irrigation and the denitrification rate was measured by the acetylene inhibition method. Nitrate-N content, aerobically mineralizable C, microbial biomass carrying capacity and denitrification potential were also studied on field-moist soil. Maize plants grown under field conditions always had the potential to increase denitrification in conditions of both high and low water-filled porosity. When nitrate-N content of the planted soil decreased due to plant uptake, denitrification was reduced in the planted soils. However, when nitrate-N uptake by plants was compensated through additional doses of nitrate fertilizer, denitrification was always higher in planted than unplanted soil. The stimulatory effect of plants on denitrification was observed at both high and low soil nitrate-N concentrations, though it was more pronounced at high nitrate-N levels. The effect of plants on denitrification and related parameters was confined to the root zone. Received: 15 April 1996     

Nitrogen nutritional status of young maize plants (Zea mays) is not limited by NaCl stress

Maize plants (Zea mays L. cv. Pioneer 3906) were grown in hydroponics with four different NaCl treatments (control, 50, 100, 150 mM NaCl). Nitrogen (N) was supplied as 2 mM Ca(NO₃)₂ in the fully concentrated nutrient solution. Plants of half of the pots were treated with additional 1 mM NH₄NO₃ 2 d after start of the NaCl application. After 23 d, the maize plants were harvested and contents and concentrations of nitrate, reduced N as well as chloride were determined in shoots and roots. With increasing NaCl stress net nitrate uptake and net root‐to‐shoot translocation of total N decreased significantly. Under salt stress, decreased nitrate concentrations in shoots probably caused substrate limitation of nitrate reductase. However, the concentrations of reduced N in shoots were not affected by salt stress and no N deficiency was observed. Additional N application to the 100 and 150 mM NaCl treatments did not improve plant growth. A Cl^?/NO antagonism was only weakly pronounced, probably because of the Cl^? exclusion ability of maize. Thus, although net uptake and net translocation of total N were markedly decreased by NaCl application, the smaller maize plants nevertheless took up enough N to meet their demand pointing to other growth‐limiting factors than N nutrition.     

近红外光谱技术定量分析玉米杂交种纯度

摘要：应用近红外光谱分析技术结合定量偏最小二乘法对先玉335杂交种纯度进行了定量分析,将不同年份和来源的杂交种和其母本种子粉碎后混合,按0.5%的梯度获得纯度80～100%范围内的样本123份（每梯度按年份和来源设置3个重复）后采集光谱。结果表明：采用散射校正预处理,4 000～8 000 cm-1光谱范围时建模效果较适宜（建模集∶检验集=3∶1）,建模集内部交叉决定系数达96.06%,校正标准差1.18%,平均相对误差1.03%;检验集的决定系数均达到95.02%,校正标准差1.28%,平均相对误差1.12%。采用不同比例的建模样品和检验样品时,建模集和检验集的决定系数均在94%以上,证明了近红外光谱技术定量测定玉米杂交种纯度的可行性以及所建模型的稳定性。     

A comparison of the availability of three zinc sources to maize (Zea mays L.) under greenhouse conditions

 The objective of this study was to compare the availability of Zn from granular ZnSO₄, a granular Zn humate-lignosulfonate (ZnHL), and liquid Zn ethylenediaminetetraacetate (ZnEDTA). The two granular sources were applied directly (“as is”) and also powdered and mixed with the soil. A calcareous sandy loam soil with low available Zn was used. Zn rates were 0, 4, 8, 16, and 32 mg pot^–1, and two crops of maize (Zea mays L.) were grown. For the first crop, all Zn sources provided an excellent dry matter response when powdered and mixed with the soil. The ZnEDTA was superior with regard to Zn uptake. The availability of ZnSO₄ granules was almost zero for the first crop. The availability of the ZnHL complex was better than ZnSO₄ when applied in granular form, but not when the two materials were powdered and mixed with the entire soil mass, suggesting that availability differences between these sources were due to physical, not chemical, factors. After mixing with the soil, only small differences existed between the Zn sources for the second crop. All sources provided for a good dry matter and Zn uptake response, and all Zn sources were about the same in increasing diethylenetriaminepentaacetate (DTPA)-extractable Zn levels at the end of the experiment. This research suggests that the three Zn materials were equal long-term Zn sources, but that the short-term response varied dramatically, depending on how the materials were applied. Received: 8 March 1999     

Brassinolide effects on maize (Zea mays L.) growth and yield under waterlogged conditions

Our aim was to assess if Brassinolide (BR) could ameliorate stress caused by waterlogging on maize. Two BR levels (with and without), two maize varieties [Ikom White (IKW) and Obatanpa-98 (Oba-98)] and three growth stages [control (WL_o), seedling stage (WL₁), and tasseling stage (WL₂)] were studied under waterlogging lasting 10 days. Maize growth and development were significantly (p?≤?.05) reduced by waterlogging stress under WL₁ than WL₂. Waterlogging stress at WL₁ adversely affected (p?≤?.05) the protein and relative water contents. The nitrogen (N) content among the plant partitions (leaves, stems, and grains) were reduced (p?≤?.05) at both silking and harvest. The beneficial effect of BR was more pronounced in Oba-98 with higher protein contents, dry matter yield, N-uptake and harvest index than IKW. Oba-98 was also better yielding than IKW. Thus, in a waterlogged soil, treatment of maize plants with BR at WL₁ could induce some tolerance.     

Morpho-physiological and biochemical response of maize (Zea mays L.) plants fertilized with nano-iron (Fe3O4) micronutrient

Nano-sized formulations of micronutrient iron (Fe) were found to substantially alter the growth and metabolism of maize plants. Plants fertilized with the optimal recommended dose of Fe in the nano-form (54 μM) registered an enhancement in morphological features, viz. plant height, biomass (shoot and root), and diminution in antioxidant enzyme activities than the plants fertilized with the sub-optimal dose of Fe in the macroform (salts). However, half of the recommended dosage of Fe (27 μM) in the nano-form positively influenced leaf area and proline content of plants too. This indicated that there is a possibility of reducing the dose of Fe supplement for plants in the nano-form to increase the nutrient use efficiency in a major cereal crop like maize. This may open a new era in plant nutrient management with a scope for improvement in nutrient use efficiency using nano-nutrient formulations.     

Morpho-physiological and yield responses to exogenous moringa leaf extract and salicylic acid in maize (Zea mays L.) under water stress

Two field experiments were executed to investigate the effects of foliar-applied moringa (Moringa oleifera) leaf extract (MLE; 1:30 w/v) and salicylic acid (SA; 0.5 mmol), singly or in combination, on growth, physio-biochemical, yield attributes and water use efficiency (WUE) of maize (Zea mays L., Three Ways Cross 329) under full and deficit irrigation conditions. Deficit irrigation was carried out by withholding water for 36 d from 12 to 48 days after sowing (DAS). At vegetative stage, deficit irrigation signi?cantly decreased all growth criteria, chlorophyll a concentration, and relative water content (RWC). In contrast, deficit irrigation considerably increased the concentrations of carotenoids, proline, membrane permeability (MP) and malondialdehyde (MDA). Similarly, grain yield, most yield components and WUE were significantly depressed in drought-stressed plants. However, foliar-applied treatments particularly MLE+SA signi?cantly increased growth traits, photosynthetic pigments, RWC and proline accumulation associated with a simultaneous decrease in MP and MDA concentration under full and deficit irrigation conditions. The application of MLE+SA markedly increased grain yield, yield components and WUE over control (spray tap water). Overall, the combined application of MLE and SA could be used for alleviating the adverse effects of growth, physiology, yield criteria and WUE in drought-stressed maize plants.