Comparative study on free amino acid composition of wild edible mushroom species

A comparative study on the amino acid composition of 11 wild edible mushroom species (Suillus bellini, Suillus luteus, Suillus granulatus, Tricholomopsis rutilans, Hygrophorus agathosmus, Amanita rubescens, Russula cyanoxantha, Boletus edulis, Tricholoma equestre, Fistulina hepatica, and Cantharellus cibarius) was developed. To define the qualitative and quantitative profiles, a derivatization procedure with dabsyl chloride was performed, followed by HPLC-UV-vis analysis. Twenty free amino acids (aspartic acid, glutamic acid, asparagine, glutamine, serine, threonine, glycine, alanine, valine, proline, arginine, isoleucine, leucine, tryptophan, phenylalanine, cysteine, ornithine, lysine, histidine, and tyrosine) were determined. B. edulis and T. equestre were revealed to be the most nutritional species, whereas F. hepatica was the poorest. The different species exhibited distinct free amino acid profiles. The quantification of the identified compounds indicated that, in a general way, alanine was the major amino acid. The results show that the analyzed mushroom species possess moderate amino acid contents, which may be relevant from a nutritional point of view because these compounds are indispensable for human health. A combination of different mushroom species in the diet would offer good amounts of amino acids and a great diversity of palatable sensations.     

Quantification of racemization of amino acids in alkaline-treated duck eggs by micellar capillary electrophoresis

Duck eggs were pickled in 4.2% NaOH/5% NaCl solution for 20 days to prepare the traditional Chinese Pidan. The extent of racemization of compositional amino acid in egg albumen and yolk over the alkaline pickling period was investigated with micellar capillary electrophoresis (MCE) using beta-cyclodextrin as chiral selector. The racemization value of amino acids in egg albumen was in the order serine > aspartic acid > glutamic acid > phenylalanine > leucine > valine > threonine = isoleucine, whereas the order in egg yolk was aspartic acid > glutamic acid > phenylalanine > leucine > valine. Therefore, the tendency of amino acid racemization appeared to be closely related to the properties of its residual side chain, as well as the pH and alkaline treating period. Moreover, racemization of most of the amino acids was remarkably induced by the alkaline treatment during the initial pickling period.     

不同防冻措施茶园茶汤滋味差异的电子舌检测

为探讨轻度“倒春寒”对不同防护措施下3种茶园蒸青茶样的茶汤滋味影响,遂选品种和管理措施一致的安装防霜扇的茶园、松树林围绕的茶园以及未设防护措施的普通茶园,用电子舌综合评价3种茶园茶汤滋味、高效液相色谱检测茶汤游离氨基酸组分及含量。结果表明：基于电子舌检测数据的主成分分析、软独立建模分析和聚类分析结果揭示了普通茶园的茶汤滋味与防霜扇茶园和林间茶园的差异显著（P<0.05）;从9种茶样中皆检测出18种氨基酸,游离氨基酸质量分数介于19.691～30.947 mg/g 之间,茶氨酸含量占游离氨基酸含量的55.1%～70.5%;随着3种茶园气温的降低,游离氨基酸含量和茶氨酸含量呈升高趋势,3种鲜味氨基酸（天冬氨酸、谷氨酸、茶氨酸）、5种甜味氨基酸（脯氨酸、丙氨酸、甘氨酸、苏氨酸、丝氨酸）和5种苦味氨基酸（异亮氨酸、亮氨酸、苯丙氨酸、酪氨酸、缬氨酸）共占游离氨基酸含量在防霜扇茶园和林间茶园中分别出现升高、降低和降低趋势,而在普通茶园中变化与之不同。分析认为：轻度“倒春寒”可导致无防护措施的普通茶园茶叶滋味劣变,林间茶园能够减轻冻害,防霜扇作为防护手段不仅可以减免冻害,还可避免茶叶滋味品质下降。该研究结果为后续深入研究不同防护措施茶园茶叶品质提供参考。     

硫素营养对小麦子粒氨基酸含量的影响

通过在缺硫农田进行2个品种的冬小麦试验,研究不同土壤供硫水平对冬小麦植株养分吸收及小麦子粒氨基酸和面筋含量的影响。结果表明,收获时小麦植株体内氮、硫的累积吸收量都受硫肥施用量的影响,但京冬8号氮、硫累积量随施硫量的变化趋势相反;而北农10号氮、硫累积量随施硫量的变化趋势一致;小麦子粒面筋几乎不受施硫水平的影响。北农10号小麦的17种氨基酸总量因施硫而明显提高,最高可提高1.97个百分点;当施硫量为60kg/hm2时,含硫的蛋氨酸含量比对照(不施硫肥)增加0.5个百分点。不含硫的天门冬氨酸、苏氨酸、丝氨酸、谷氨酸、甘氨酸、亮氨酸、苯丙氨酸等含量因硫肥的施用而有所提高,但是达到最大含量的硫肥用量差别很大;京冬8号小麦的17种测定氨基酸中,含硫的胱氨酸含量增加百分率幅度最大,达7%～28%。     

Free amino acids of tronchuda cabbage (Brassica oleracea L. Var. costata DC): influence of leaf position (internal or external) and collection time

The free amino acid profile of 18 samples of tronchuda cabbage ( Brassica oleracea L. var. costata DC) leaves, harvested at three different months, was determined by HPLC/UV-vis. The tronchuda cabbage leaves total free amino acid content varied from 3.3 to 14.4 g/kg fresh weight. Generally, arginine was the major compound, followed by proline, threonine, glutamine, cysteine, and glutamic acid. This study indicates that free amino acids are not similarly distributed: in external leaves, proline and arginine were the major free amino acids, while in internal ones, arginine was the main free amino acid, followed by threonine, glutamine, and cysteine. Significant differences were observed for valine, proline, arginine, leucine, cysteine, lysine, histidine, and tyrosine contents. The levels of some free amino acids were significantly affected by the collection period. In external leaves, this occurred with glutamic acid, serine, valine, leucine, cysteine, and ornithine contents, while in internal leaves, it occurred with aspartic acid, arginine, and total contents.     

Differentiation of tea (Camellia sinensis) varieties and their geographical origin according to their metal content

The metal content of 46 tea samples, including green, black, and instant teas, was analyzed. Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, Sr, Ti, and Zn were determined by ICP-AES. Potassium, with an average content of 15145.4 mg kg(-1) was the metal with major content. Calcium, magnesium, and aluminum had average contents of 4252.4, 1978.2, and 1074.0 mg kg(-1), respectively. The average amount of manganese was 824.8 mg kg(-1). There were no clear differences between the metal contents of green and black teas. Pattern recognition methods such as principal component analysis (PCA), linear discriminant analysis (LDA), and artificial neural networks (ANN), were applied to differentiate the tea types. LDA and ANN provided the best results in the classification of tea varieties. These chemometric procedures were also useful for distinguishing between Asian and African teas and between the geographical origin of different Asian teas.     

玉米浆发酵产生物丁醇的氨基酸代谢动力学模拟

为了深入挖掘利用丙酮丁醇梭菌产生物丁醇过程中氨基酸代谢的动态过程,探究利用廉价氮源玉米浆中的氨基酸用于丙酮丁醇梭菌产生物丁醇的生产策略,寻找生产丁醇的高效率廉价氮源来降低发酵生产成本。该研究首先利用高通量测序技术对玉米浆中微生物多样性进行分析;同时基于丙酮丁醇梭菌（Clostridium acetobutylicum）生产丙酮-丁醇-乙醇（Acetone-Butanol-Ethanol,ABE）碳代谢动态模型的基础上,构建氨基酸代谢模型,以此模拟15种氨基酸在利用木糖为碳源发酵生产ABE中的氨基酸代谢过程,并对氨基酸的代谢与丙酮丁醇梭菌的生物量以及ABE的合成相关性关系进行冗余分析;通过模型预测实际生产中利用玉米浆发酵时氨基酸的消耗过程。结果表明,梭状芽胞杆菌属（Clostridium）占细菌总数的68.76%,是玉米浆中的优势菌群;最佳参数校正后构建了氨基酸代谢模型,模拟值与试验值有较好拟合度;11种氨基酸（苯丙氨酸、苏氨酸、异亮氨酸、亮氨酸、蛋氨酸、缬氨酸、酪氨酸、甘氨酸、丝氨酸、精氨酸、天冬酰胺）在培养过程中迅速消耗用于细胞生长和溶剂生成,3种氨基酸（脯氨酸、组织胺、天冬氨酸）保持稳定状态,同时发酵过程中谷氨酰胺积累;冗余分析表明其中5种氨基酸对发酵产物及生物量影响具有相关性（P<0.05）,相关性排序从大到小依次为丝氨酸、甘氨酸、亮氨酸、缬氨酸、天冬酰胺;模拟预测玉米浆中缬氨酸、甘氨酸、丝氨酸在发酵过程中基本被消耗,推测其为发酵后期的营养限制性因子。该结论可证实玉米浆可作为丙酮丁醇梭菌发酵丁醇的优势氮源,为丙酮丁醇梭菌的氨基酸代谢调控及下一步利用并优化玉米浆作为氮源生产生物丁醇提供一定的理论参考和数据支撑。     

Biochemical and microbial changes during the storage of minimally processed cantaloupe

The effect of storage time on pH, titratable acidity, degrees Brix, organic acids, sugars, amino acids, and color of minimally processed cantaloupe melon (Cucumis melo L. var. reticulatus Naud. cv. Mission) was determined at 4 degrees C and 20 degrees C. Changes in most of the biochemical parameters with storage time were relatively slow at the lower temperature. At 20 degrees C, a 17% loss in soluble solids and a 2-fold increase in acidity occurred after 2 days. Organic acid content also increased considerably with time at this temperature as a result of the production of lactic acid. Oxalic, citric, malic, and succinic acids were the organic acids, and glucose, fructose, and sucrose were the sugars present in the freshly cut cantaloupe. Malic acid concentration decreased concurrently with lactic acid production indicating the possible involvement of anaerobic malo-lactic fermentation along with sugar utilization by lactic acid bacteria. The effect of storage on microbial growth was determined at 4, 10, and 20 degrees C. Gram-negative stained rods grew at a slower rate at 4 degrees C and 10 degrees C than the Gram-positive mesophilic bacteria that dominated microorganism growth at 20 degrees C. Eighteen amino acids were identified in fresh cantaloupe: aspartic acid, glutamic acid, asparagine, serine, glutamine, glycine, histidine, arginine, threonine, alanine, proline, tyrosine, valine, methionine, isoleucine, leucine, phenyl alanine, and lysine. The dominant amino acids were aspartic acid, glutamic acid, arginine, and alanine. Total amino acid content decreased rapidly at 20 degrees C, but only a slight decrease occurred at 4 degrees C after prolonged storage. Changes in lightness (L), chroma, and hue at both temperatures indicate the absence of browning reactions. The results indicate the potential use of lactic acid and lactic acid bacteria as quality control markers in minimally processed fruits.     

氨基酸部分替代硝态氮对小白菜生长、硝酸盐累积及大量元素含量的影响

A hydroponic experiment was carried out to determine the influence of replacing 20% of nitrate-N in nutrient solutions with 20 individual amino acids on growth, nitrate accumulation, and concentrations of nitrogen （N）, phosphorus （P）, and potassium （K） in pak-choi （Brassica chinensis L.） shoots. When 20% of nitrate-N was replaced with arginine （Arg） compared to the full nitrate treatment, pak-choi shoot fresh and dry weights increased significantly （P ≤ 0.05）, but when 20% of nitrate-N was replaced with alanine （Ala）, valine （Val）, leucine （Leu）, isoleucine （Ile）, proline （Pro）, phenylalanine （Phe）, methionine （Met）, aspartic acid （Asp）, glutamic acid （Glu）, lysine （Lys）, glycine （Gly）, serine （Ser）, threonine （Thr）, cysteine （Cys）, and tyrosine （Tyr）, shoot fresh and dry weights decreased significantly （P ≤ 0.05）. After replacing 20% of nitrate-N with asparagine （Asn） and glutamine （Gin）, shoot fresh and dry weights were unaffected. Compared to the full nitrate treatment, amino acid replacement treatments, except for Cys, Gly, histidine （His）, and Arg, significantly reduced （P ≤0.05） nitrate concentrations in plant shoots. Except for Cys, Leu, Pro, and Met, total N concentrations in plant tissues of the other amino acid treatments significantly increased （P ≤ 0.05）. Amino acids also affected total P and K concentrations, but the effects differed depending on individual amino acids. To improve pak-choi shoot quality, Gln and Asn, due to their insignificant effects on pak-choi growth, their significant reduction in nitrate concentrations, and their increase in macroelement content in plants, may be used to partially replace nitrate-N.     

Changes in the free amino acid composition with maturity of the noble cultivar of Vitis rotundifolia Michx. grape

The changes in amino acid composition that occur with maturity of the Noble cultivar of the Vitis rotundifolia Michx. (muscadine) grape were determined by HPLC. Eighteen amino acids were identified. Histidine was the most prominent amino acid followed by alanine. The concentrations of most of the major amino acids (alanine, glycine, histidine, valine, isoleucine, aspartic acid, and serine) were highest at verasion. Glutamine and threonine contents dropped sharply after fruit set, while those of arginine and proline increased gradually with maturity and ripening. Tyrosine content increased gradually with maturity and ripening following a slight drop after fruit set. In ripe grapes, seeds contained most of the amino acids in mature grapes (50%) followed by the pulp (23%), the juice (15%), and the skin (11%). Alanine, histidine, and arginine were the principal amino acids identified in the juice. Alanine, histidine, arginine, valine, glutamine, aspartic acid, proline, serine, and threonine accounted for about 90% of the amino acids in the pulp. In seeds, alanine, proline, asparagine, and histidine accounted for over 55% of the amino acids, while alanine and histidine were found to be the predominant free amino acids in the skin. The profile indicates some differences in the changes in amino acid composition with berry maturity and relative amounts of amino acids present in muscadine compared to those in nonmuscadine grape species.     

Identification of free amino acids in peat by gas chromatography and mass spectrometry

The qualitative and quantitative composition of free amino acids in a typical Finnish peat bog at various depths down to 5.3 m below the surface was studied using capillary gas chromatography and mass spectrometry. Sixteen amino acids were identified at each depth: α-alanine, β-alanine, glycine, valine, leucine, proline, isoleucine, serine, threonine, glutamic acid, aspartic acid, phenylalanine, tyrosine, γ-aminobutyric acid, ornithine and lysine. Their amounts decreased markedly at a depth of 40–100 cm. The total amount of amino acids varied between 0.6 and 5.6 g kg^?1 dry matter (i.e. 0.06–0.56%) depending on the depth. The proportion of neutral amino acids was greatest at all depths studied, except at the surface layer where it ranged between 41 and 72% by mass. The acidic amino acids decreased with depth from 56 to 23% of the total. The proportion of aromatic amino acids was very small, 3.2–5.5% by mass. In samples from aerobic conditions, where the microbial production of free amino acids was the greatest, α-ala, gly, glu and asp were most abundant. In peat from anaerobic conditions, where the microbiological activity was low, the proportion of the most chemically stable amino acid was exceptionally high. This may have been because glycine was a degradation product of other amino acids or peptides. Peat type and degree of decomposition had a strong influence on the total amount of free amino acids and their qualitative composition.     

稻米品质近红外光谱法分析中定标样品选择与模型优化

通过对粳型水稻精米粉的直链淀粉含量和氨基酸含量近红外光谱检测模型的定标样品数量和优化的分析,用新复极差检验对不同样品组的粳稻精米粉直链淀粉含量和谷氨酸、亮氨酸含量的近红外建模效果校正决定系数(R2)和交叉检验均方误差(RMSECV)进行了评价,发现样品数为216份、114份、81份的直链淀粉含量样品组间无显著差异,200份、132份、91份谷氨酸和200份、113份和70份亮氨酸含量的样品组间无显著差异。结果表明,优选合适的样品及数量,并对模型进行优化,不仅可保持定标方程的精度,也可节约成本、减少工时。在本试验中,直链淀粉、谷氨酸和亮氨酸含量分别选择81、91、70份分布均匀的样品,可满足各自的建模要求。     

高氨基酸和高茶氨酸茶树资源筛选

为筛选高氨基酸和高茶氨酸茶树资源及探究茶树中茶氨酸与氨基酸含量之间的关系,本研究利用茚三酮显色法结合酶标仪检测技术测定218份茶树资源春季一芽二叶蒸青样的氨基酸含量,利用高效液相色谱法测定了其茶氨酸含量。结果表明,218份资源的氨基酸含量介于1.50%~8.98%之间,其中高氨基酸茶树资源(氨基酸含量≥5%)55份;茶氨酸含量介于0%~4.03%之间,其中高茶氨酸茶树资源(茶氨酸含量≥3%)13份,不含茶氨酸的茶树资源4份;茶氨酸与氨基酸含量的比值介于0~0.78之间,且集中分布于0.2~0.5之间,二者的相关性系数达0.752,呈极显著正相关。本研究筛选获得了一批氨基酸特异的茶树资源,为高氨基酸和高茶氨酸茶树新品种选育及其形成的分子机理研究奠定了基础。     

Cucumber performance is improved by inoculation with plant growth-promoting microorganisms

We investigated the effects of inoculation of Rhodobacter sphaeroides, Lactobacillus plantarum, and Saccharomyces cerevisiae on cucumber plant growth promotion and on the contents of plant hormones, amino acids, and mineral nutrients. We showed that treatment with all three bio-inoculants significantly increased the shoot length, root length, shoot fresh weight, shoot dry weight, and chlorophyll content, via secretion of indole acetic acid and/or organic acids. Inoculation with R. sphaeroides had more favorable effect on plant growth than did inoculation with L. plantarum or S. cerevisiae, by significantly enhancing the gibberellin and reducing the abscisic acid contents. The results of amino acid analysis revealed that inoculation with R. sphaeroides, L. plantarum, and S. cerevisiae generally increased the contents of 17 amino acids, namely, aspartic acid, threonine, serine, glutamic acid, glycine, alanine, cysteine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, arginine, and proline. With the exception of cysteine, all these amino acids were present in higher concentrations in plants inoculated with R. sphaeroides than in control plants or in plants inoculated with L. plantarum and S. cerevisiae. Furthermore, inoculation with R. sphaeroides significantly increased the calcium, potassium, magnesium, and phosphate contents. Our results suggest that the use of R. sphaeroides, L. plantarum, and S. cerevisiae in agricultural fields can improve plant growth. Moreover, inoculation of cucumber plants with R. sphaeroides regulates plant functional metabolites, thereby promoting plant growth.     

不同品种樱桃番茄氨基酸组成及风味分析

为评价不同品种樱桃番茄的风味及营养价值,比较分析了8个品种樱桃番茄的可溶性固形物含量、总糖含量、有机酸含量、糖酸比、Vc含量、氨基酸含量和氨基酸组成。结果表明,红果樱桃番茄品种的部分风味指标(可溶性固形物、总糖、有机酸、Vc)、氨基酸组成及营养价值(总氨基酸、必需氨基酸含量及氨基酸模式谱)优于黄果品种,尤其是红果品种浙樱粉1号和浙樱红1号,其中,浙樱粉1号樱桃番茄可溶性固形物含量、总糖含量、有机酸含量、Vc含量、呈味类氨基酸(鲜味、甜味、芳香类)含量及氨基酸营养价值均处于较高水平。红果樱桃番茄品种之间的总糖含量、Vc含量,以及黄果樱桃番茄品种之间的有机酸含量、总氨基酸含量、必需氨基酸含量和甜味类氨基酸含量等指标均呈现出较低的变异系数。氨基酸营养价值分析表明,缬氨酸和亮氨酸是樱桃番茄的2个主要限制氨基酸。本研究结果为高品质樱桃番茄的品种选育提供了理论指导。     

Determination of theanine, GABA, and other amino acids in green, oolong, black, and Pu-erh teas with dabsylation and high-performance liquid chromatography

Dabsyl chloride (dimethylaminoazobenzene sulfonyl chloride), a useful chromophoric labeling reagent for amino acids and amines, was developed in this laboratory in 1975. Although several methods have been developed to determine various types of amino acids, a quick and easy method of determining theanine, GABA, and other amino acids has not been developed in one HPLC system. In this paper are analyzed the free amino acid contents of theanine and GABA in different teas (green tea, black tea, oolong tea, Pu-erh tea, and GABA tea) with a dabsylation and reverse phase high-performance liquid chromatography (HPLC) system coupled with a detector at 425 nm absorbance. Two reverse phase columns, Hypersil GOLD and Zorbax ODS, were used and gave different resolutions of dabsyl amino acids in the gradient elution program. The data suggest that the tea source or the steps of tea-making may contribute to the theanine contents variations. High theanine contents of high-mountain tea were observed in both green tea and oolong tea. Furthermore, the raw (natural fermented) Pu-erh tea contained more theanine than ripe (wet fermented) Pu-erh tea, and the GABA contents in normal teas were generally lower than that in GABA tea.     

绿茶施用铵态氮和硝态氮后木质部导管中N运移模拟

An experiment was carried out to study the transport process of nitrogen （N） assimilation from tea roots by monitoring the dynamic composition of N compounds in xylem sap after 15^N-NO3 and 15^N-NH4 were fed to the root of tea plants （Camellia sinensis L.）. Results showed that the main amino acids were glutamine, theanine, axginine, asparic acid and glutamic acid, which accounted for 49%, 17%, 8%, 7%, and 4%, respectively, of the total amino acids in the xylem sap. After the tea plants were fed with 15^N-NO3 and 15^N-NH4 for 48 h, the amount of total amino acids in xylem sap significantly increased and those fed with 15^N-NH4 had higher increment than those with 15^N-NOa. Two hours after 15^N- NO3 and 15^N-NH4 were fed, 15N abundance in glutamine, asparagine, glutamic acid, alanine, and arginine were detected and increased quickly over time. This indicated that it took less than 2 h for NO3-N and NH4-N to be absorbed by tea roots, incorporated into the above amino acids and transported to the xylem sap. Rapid increase in 15^N-NO3 in the xylem sap of tea plants fed with 15^N-NO3 indicated that nitrate could be directly transported to the xylem sap. Glutamine, theanine, and alanine were the main amino acids transported in xylem sap of tea plants fed with both 15^N-NO3 and 15^N-NH4.     

Influence of yeast strain and aging time on free amino acid changes in sparkling ciders

An analytical method for the determination of free amino acids in ciders is reported. It is based on high-performance liquid chromatography with an automatic precolumn derivatization with o-phthaldehyde and 3-mercaptopropionic acid and diode array detection. The method was applied to monitor the amino acids during second fermentation of sparkling ciders. This paper reports the influence of yeast strains and aging time on the amino acid composition of sparkling ciders. The application of principal component analysis enables the ciders to be differentiated on the basis of the two factors considered (yeast strain and aging time). The first principal component, which accounts for 58% of the total variance, achieved the separation according to aging time with serine, glycine, alanine, valine, ornithine, leucine, and lysine as the most important variables. The second principal component, accounting for 28% of the explained variance, is closely related to aspartic acid and asparagine and separates the samples according to the yeast strain.     

Changes in the free amino acid contents of honeys during storage at ambient temperature

This study was carried out to establish the changes in the free amino acid contents of floral honeys, honeydew honeys, and blend honeys during storage at room temperature and to test the capacity of the amino acids to distinguish the origin of the honeys after storage. For this purpose, 54 artisanal honeys (39 floral, 5 honeydew, and 10 blend) were studied. Samples were taken from recently collected honeys and at 3, 6, 9, 12, 16, 20, and 24 months after harvesting. The contents of most of the free amino acids were found to decrease with storage time, with the greatest reduction observed in the first 9 months. The contents of the amino acids aspartic acid, beta-alanine, and proline increased in the first few months after storage, reaching maximum values at 6 months, suggesting the possible existence of enzymatic activities. The application of stepwise discriminant analysis to the free amino acid content data demonstrated that the contents of the amino acids valine, beta-alanine, gamma-aminobutyric acid, serine, isoleucine, alpha-alanine, ornithine, and glutamine correctly assigned 87% of honeys to their group of origin: floral, honeydew, or blend.     

江河源区高寒嵩草草甸土壤氨基酸成分和含量特征分析

通过高效液相色谱技术分析了青海省果洛州达日县窝赛乡原生嵩草草甸、严重退化草地及人工草地三类植被土壤中各种氨基酸成分及含量。结果表明:(1)三种类型土壤中都检测出19种常见氨基酸:精氨酸、天冬氨酸、丝氨酸、谷氨酸、苏氨酸、丙氨酸、甘氨酸、氨基丁酸、脯氨酸、蛋氨酸、缬氨酸、苯丙氨酸、异亮氨酸、亮氨酸、胱氨酸、组氨酸、鸟氨酸、赖氨酸、酪氨酸;(2)测定结果表明原生嵩草草甸土壤的氨基酸总量显著高于人工恢复重建草地和严重退化土壤氨基酸,而后两者之间差异不显著。原生高寒草地的土壤(6316.28μgg-1)严重退化草地土壤(2977.10μgg-1)人工恢复重建草地土壤(2975.90μgg-1)。(3)原生高寒草地土壤氨基酸总体呈现下降趋势:5月氨基酸含量最高,随后6月7月的显著下降,8月稍微有所回升,9月氨基酸含量到达最低;严重退化草地土壤与人工恢复重建草地土壤氨基酸含量季节变化相似,氨基酸总量在6月份到达最高点,随后7月8月显著下降,9月份稍微有所回升。