长期施肥条件下不同粒径土壤团聚体中Bradford反应土壤蛋白质含量的差异

主要研究了稻-稻连作方式下长期不同施肥对不同粒径土壤团聚体中Bradford反应土壤蛋白质（BRSP）含量的影响及BRSP与土壤有机碳（SOC）和全氮（TN）之间的关系，同时为简化BRSP测定过程，探讨了用过1mm筛土壤代替1～2mm土壤团聚体研究BRSP含量的可行性。研究结果表明，长期不同施肥显著影响土壤1～2mm团聚体中总BRSP（T—BRSP）和易浸提BRSP（EE—BRSP）含量。有机无机肥料配合施用能显著提高土壤中BRSP含量，以NPK＋稻草还田提高BRSP含量的效果最佳。经25a施用不同肥料后，1—2mm土壤团聚体中2种形态BRSP含量与土壤SOC和TN含量呈显著正相关。试验发现，〈1mm土壤团聚体中同样有BRSP，且处理间的变化趋势与1～2mm团聚体间的变化趋势相似。试验结果显示，过1mm筛土壤中T—BRSP和EE—BRSP含量与1～2mm团聚体中含量的相关性均达到极显著水平，且土壤SOC和TN含量的相关性也均达到极显著水平。

胶园球囊霉素相关土壤蛋白质及有机质特征

为研究海南白沙不同利用历史橡胶林土壤球囊霉素相关土壤蛋白质(glomalin-related soil protein)及有机质特征,采用热柠檬酸钠(121℃)提取、用Bradford染色法测定球囊霉素相关土壤蛋白质。结果表明,海南白沙橡胶林土壤中球囊霉素相关土壤蛋白质含量低于3.56mg/g。相差8年的橡胶种植历史对土壤中球囊霉素相关土壤蛋白质含量的影响不显著。与第一代橡胶林各层次之间的土壤球囊霉素相关土壤蛋白质含量变异相比,第二代橡胶林各层次之间的土壤球囊霉素相关土壤蛋白质含量变异相对较小。橡胶林土壤有机质含量与土壤球囊霉素相关土壤蛋白质含量变化趋势并不一致。因此,橡胶种植历史对土壤中球囊霉素相关土壤蛋白质含量的影响不明显。

土壤宏蛋白质组学之土壤蛋白质提取技术的发展

随着土壤宏基因组学的日益成熟和发展,作为后基因组时代重要技术平台的土壤宏蛋白质组学越来越受到关注。土壤宏蛋白质组学的研究是解析土壤宏基因功能的重要手段之一,对于碳氮磷的生物地球化学循环以及土壤有机质积累的研究具有重大价值,可将蛋白信息与相关的生态系统过程联系起来。但是,土壤蛋白含量少,样品复杂程度高,极大限制了土壤蛋白的分离提取和进一步分析。因此,通过改进和优化土壤蛋白的提取技术,得到高浓度的蛋白是土壤宏蛋白质组学研究的前提条件。本文总结了近几年来土壤蛋白提取方法,并对其适用的土壤性质以及适用的不同种类和功能的蛋白进行了分析。此外,本文也对现有的土壤蛋白提取技术以及土壤蛋白鉴定技术的方法改进进行了探讨。

AM真菌接种和生草刈割对盆栽初生枳生长和土壤结构的影响

在温室中,研究了盆栽基质接种丛枝菌根(arbuscular mycorrhiza,AM)真菌摩西管柄囊霉Funneliformis mosseae对初生(种子播种育苗2个月后的幼苗)枳Poncirus trifoliata生长、菌根侵染、菌丝长度、土壤球囊霉素相关土壤蛋白(GRSP)含量和土壤结构的影响;同时研究了在AM真菌接种和柱花草间作条件下柱花草刈割对初生枳和柱花草生长、菌根侵染、土壤GRSP含量和土壤结构的影响。结果表明,与不接种相比,接种AM真菌显著地促进了初生枳生长,增加了土壤GRSP含量,并且土壤结构也得到改善。在AM真菌接种与柱花草间作的相同条件下,与柱花草未刈割相比,柱花草刈割对初生枳生长、菌根侵染、土壤GRSP含量和土壤结构均无显著性影响,但柱花草未刈割处理的菌丝长度是刈割处理的2.5倍。相关性分析表明,根际土壤大团聚体显著地与菌根侵染率、土壤GRSP含量和菌丝长度正相关,而生草刈割影响了丛枝菌根真菌菌丝长度,可能对土壤结构有不利影响。

土壤宏蛋白质组学在土壤污染评价中的应用

土壤微生物指标是评价土壤污染程度的重要生物学指标之一.近年来,随着分子生物学的发展,应用宏基因组学、宏转录组学和宏蛋白质组学技术考察土壤微生物的生态功能成为土壤功能的研究热点.相对于宏基因组学和宏转录组学,土壤宏蛋白质组学是以土壤微生物基因的功能组分——蛋白质为直接研究对象,考察不同时空点提取出来的土壤蛋白质的变化规律,更有助于揭示土壤微生物的生态功能及其在污染物迁移转化过程中的作用,在评价土壤污染方面也更具潜力.目前,土壤宏蛋白质组学正处于起步阶段,而土壤蛋白质的提取方法是制约其发展的主要因素之一,因此本文综述了蛋白质作为土壤污染评价指标的优势,重点比较了不同土壤蛋白质提取方法的优劣,结合案例分析了蛋白质作为土壤污染评价指标的可行性及存在的问题,并对土壤宏蛋白质组学的发展进行展望.

土地利用变化对海南热带土壤球囊霉素的影响

为海南热带土壤资源的合理利用提供依据,采用20 mmol/L的热柠檬酸钠（121℃）提取海南白沙次生林、水田以及橡胶林剖面（0~50 cm）土壤中球囊霉素相关土壤蛋白质含量,用Bradford染色法进行测定,研究了土地利用变化对海南热带土壤球囊霉素的影响。结果表明：海南次生林、水田以及橡胶林土壤中球囊霉素相关土壤蛋白质含量相对较低,0~10 cm土层中球囊霉素相关土壤蛋白质含量最高,为3.43~4.78 mg/g;20~50 cm土层中球囊霉素相关土壤蛋白质含量最低,为1.5~2.36 mg/g。海南次生林、水田和橡胶林0~20 cm土壤中球囊霉素相关土壤蛋白质含量分别显著高于相同利用方式20~50 cm土壤层次中球囊霉素相关土壤蛋白质含量。土地利用方式由次生林转变为水田和橡胶林对0~20 cm土壤层中球囊霉素相关土壤蛋白质含量没有影响,使得20~50 cm土壤中球囊霉素相关土壤蛋白质含量显著降低。

酸化茶园茶树根际土壤微生物蛋白质代谢图谱构建

土壤是茶树生长的载体,在我国茶园普遍存在土壤酸化现象,但是土壤微生物如何响应土壤酸化以及如何影响茶树生长还鲜有报道.本研究以不同酸度的铁观音茶树种植土壤为材料,分别提取茶树根际土壤微生物蛋白质,采用数据依赖采集(data dependent acquisition, DDA)技术建立茶树根际土壤微生物蛋白质数据库,并采用数据非依赖采集(data independent acquisition, DIA)技术定量分析土壤微生物蛋白质,获得不同酸度茶树根际土壤丰度降低的蛋白质并对其进行功能分析,构建了茶树根际土壤蛋白质组代谢调控图谱.结果表明,茶树根际土壤共检测到微生物蛋白质2741种,分子量主要分布在2.64~338.33 kD之间, pI主要分布在3.78~12.15之间.蛋白质定量分析结果表明,不同酸度茶树根际土壤中共有54种微生物蛋白质丰度下降,按其功能主要可分为遗传信号蛋白、能量代谢信号蛋白、土壤抗氧化信号蛋白、土壤养分循环信号蛋白.基于此结果构建的土壤微生物蛋白质组代谢调控图谱表明,随着茶园土壤酸化加剧,土壤微生物为了生存,释放群体感应蛋白质,激发信号蛋白质的表达;在信号通路蛋白质的调控下,信号蛋白质激发不同代谢途径的特定信号蛋白质表达,进而调控不同代谢途径中的蛋白质表达,而这种表达是下调式的;最终导致微生物能量代谢循环能力下降,繁殖能力降低,数量减少.微生物数量及功能的变化导致土壤养分循环能力减弱,茶树在养分吸收上受阻,进而引起茶树生长受阻,以及茶叶产量和品质下降.

Relationships among Glomalin Related Soil Protein,Soc and Soil Texture under Different Land Use Types

[Objective] The aim was to reveal the effects of different land use types on soil composition. [Method] GPRS,soil organic carbon content and soil texture in 3 depths (0-10,10-20,20-50 cm) of 5 main kind of selected land use type were examined in Hainan. [Result] The results showed that GRSP and SOC content of four artificial land use types decreased compared with the natural secondary forest land,the GRSP content of all samples ranged from 0.53-4.80 mg/g,accounting for 7.9%-23.4% of the SOC,which means that GRSP was one important component of SOC pool in soil. The ratio of GRSP to SOC was significantly different among land use types but the depths. GRSP and SOC exhibited obvious vertical distribution pattern. GRSP was significantly positively related to SOC and sand content but negatively related to silt and clay content. [Conclusion] The sand content determined the GRSP content significantly and loam was better matrix for GRSP accumulation than clay.

Predicting Grain Yield and Protein Content in Winter Wheat at Different N Supply Levels Using Canopy Reflectance Spectra

A field experiment using a split-plot randomized complete block design with three replications was carried out to determine relationships between spectral indices and wheat grain yield （GY）, to compare the performance of four vegetation indices （VIs） for GY prediction, and to study the feasibility of VI to estimate grain protein content （GPC） in winter wheat. Two typical winter wheat （Triticum aestivum L.） cultivars ＇Xuzhou 26＇ （high protein content） and ＇Huaimai 18＇ （low protein content） were used as the main plot treatments and four N rates, i.e., 0, 120, 210, and 300 kg N ha^-1, as the sub-plot treatments. Increasing soil N supply significantly increased GY and GPC （P ≤ 0.05）. For the two cultivars combined, significant and positive correlations were found between four VIs and GY, with the strongest relationship observed when using the green ratio vegetation index （GRVI） at mid-filling. Cumulative VI estimates improved yield predictions substantially, with the best interval being heading to maturity stage. Similar results were found between VI and grain protein yield. However, when using cumulative VI, GPC showed no significant improvement. The strong relationship between leaf N status and GPC （R2 =0.9144 for ＇Xuzhou 26＇ and R2 = 0.8285 for ＇Huaimai 18＇） indicated that canopy spectra could be used to predict GPC. The strong fit between estimated and observed GPC （R2 = 0.7939） indicated that remote sensing techniques were potentially useful predictors of grain protein content and quality in wheat.

Influence of Nitrogen Levels and Application Methods on Yield and Quality of Sorghum

A field study was conducted for two years at the Arid Zone Research Institute, Dera Ismail Khan, Pakistan, to determine the optimum level of nitrogen and efficient application method in the production of sorghum （Sorghum bicolor L.）. Using four levels of nitrogen, i.e., 0, 60, 90, and 120 kg ha^-1, and two different application methods （soil application and foliar spray）, the experiment was laid out in a split-plot design, where the main plots were used to determine the effective method of application and the subplots were used to detect the influence of N levels on the grain yield. The average data obtained after two years of study indicated an increase in the grain yields with an increase in N levels irrespective of the method used of N application. The grain yield increased from 2.92 to 5.61 t ha^-1 in the plots that were treated with 90 kg N ha^-1 compared with the control plots. Quadratic regression analysis showed that the increase in the yield was higher at the lower levels of N compared with the succeeding higher levels. The soil application method, producing an average grain yield of 4.79 t ha^-1, was found to be superior to the foliar spray method with an average grain yield of 4.56 t ha^-1. The protein content of the grain showed a linear increase with N application, attaining the maximum at 120 kg N ha^-1 in both the methods of N application. In addition, compared with the method of soil application, higher crude protein contents were observed using the method of foliar spray at all N levels.

Alteration of certain soil microbiological and biochemical indices of a paddy soil under anthropogenic stress

A 21-day laboratory incubation experiment was conducted to investigate the impact of pesticides (insecticide, herbicide, fungicide) on paddy field soil health under controlled moisture (flooded soil) and temperature (25 ℃) environment. The electron transport system (ETS)/Dehydrogenase activity showed negative correlation with pesticides concentrations, decreased with increase of pesticide concentration. The higher doses(5 to 10 times field rates) of pesticides significantly inhibited ETS activity, while lower rates failed to produce any significant reducing effect on the control. The toxicity of pesticides in decreasing the ETS activity was in the order: insecticide > fungicide > herbicide, irrespective of their rates of application. The pesticides increased the soil phenol content, which increased with increasing concentration of agrochemicals. The pesticide application did not produce any significant change in soil protein content. The response of biomass phospholipid content was nearly similar to that of ETS activity. The phospholipid content decreased with the addition of pesticides in the order insecticide > fungicide > herbicide and the toxicity was in the order: 10 FR (field rate) > 5 FR > 1.0 FR > 0.5 FR > control.

Tracing Changes in the Microbial Community of a Hydrocarbon-Polluted Soil by Culture-Dependent Proteomics

Hydrocarbon contamination may affect the soil microbial community, in terms of both diversity and function. A laboratory experiment was set-up, with a semi-arid control soil and the same soil but artificially contaminated with diesel oil, to follow changes in the dominant species of the microbial community in the hydrocarbon-polluted soil via proteomics. Analysis of the proteins extracted from enriched cultures growing in Luria-Bertani （LB） media showed a change in the microbial community. The majority of the proteins were related to gIycolysis pathways, structural or protein synthesis. The results showed a relative increase in the complexity of the soil microbial community with hydrocarbon contamination, especially after 15 days of incubation. Species such as Ralstonia solanacearum, Synechococcus elongatus and different Clostridium sp. were adapted to contamination, not appearing in the control soil, although Bacillus sp. dominated the growing in LB in any of the treatments. We conclude that the identification of microbial species in soil extracts by culture-dependent proteomics is able to partially explain the changes in the diversity of the soil microbial community in hydrocarbon polluted semi-arid soils, but this information is much more limited than that provided by molecular methods.

Adsorption and Desorption of Cry1Ab Proteins on Differently Textured Paddy Soils

In recent years, selected cry genes from Bacillus thuringiensis（Bt） encoding the production of Cry proteins（Bt toxins） have been engineered into crop plants（Bt-crops）. Through the cultivation of Bt crops and the application of Bt pesticides, Cry proteins could be introduced into arable soils. The interaction between the proteins and soils was analyzed in this study to investigate the affinity of Cry proteins in paddy soil ecosystems. Four Paddy soils were selected to represent different soil textures. Cry proteins were spiked in soils, and the amount of protein adsorbed was measured over 24 h. Desorption of Cry1Ab proteins from paddy soils was performed by washing with sterile Milli-Q water（H_2O_（MQ））, and subsequently extracted with an extraction buffer. The paddy soils had a strong affinity for Cry1Ab proteins. Most of the Cry1Ab proteins added（＆gt; 98%） were rapidly adsorbed on the paddy soils tested. More Cry1Ab proteins were adsorbed on non-sterile soils than on sterile soils. Less than 2% of the adsorbed Cry1Ab proteins were desorbed using H2 OMQ, while a considerable proportion of the adsorbed proteins could be desorbed with the buffer, ranging from 20% to 40%.The amount of proteins desorbed increased with the increases in the initial amount of Cry1Ab proteins added to the paddy soils. The concentration of Cry1Ab proteins desorbed from the paddy soils was higher for sterile soils than non-sterile ones. Our results indicate that Bt toxins released via the cultivation of Bt crops, the application of Bt pesticides can be adsorbed on paddy soils, and soil texture could impose an impact on the adsorption capability.