Partitioning of soil respiration components and evaluating the mycorrhizal contribution to soil respiration in a semiarid grassland北大核心CSCD

Aims Soil respiration component partitioning is pivotal to understand the belowground carbon (C) cycle. Mycorrhizal fungi have been proven to play an important role in the soil C turnover, but only a few studies have been conducted to quantify the contribution of mycorrhizal respiration to total soil respiration in grassland ecosystems. Methods The mini-trenching mesh method was applied to partition soil respiration components of a semi-arid grassland in Inner Mongolia. A shallow collar (measuring soil total respiration), a deep collar (excluding roots and mycorrhizal hypahe) and a deep collar with 40 μm pore mesh window (excluding roots but not mycorrhizal hyphae) were installed in each plot. Soil respiration rate of each collar was measured every two weeks during the growing season from 2014 to 2016. The differences in the rate of soil respiration among different type of collars were used to partition the components of soil respiration. Important findings The results showed that the contribution of heterotrophic, root and mycorrhizal respiration to total soil respiration was 49%, 28%, and 23%, respectively. Across the three years, the proportion of mycorrhizal respiration varied from 21%-26%, which is comparable with the results reported by other studies recently. Our results demonstrated that the mini-trenching mesh method is a suitable method for separating mycorrhizal respiration component in grassland ecosystems. Evaluating the contribution of mycorrhizal respiration to total soil respiration is very important for predicting the responses of soil carbon release to future climate change. © 2018 Editorial Office of Chinese Journal of Plant Ecology. All rights reserved.     

拉杰沙希大学校园药用植物菌根研究

Forty different medicinal plants were investigated for arbuscular mycorrhizal association in the Rajshahi University Campus in Bangladesh. The results indicated that 35 different plants were infected by AM (arbuscular mycorrhizal) fungi as found by trypan blue staining procedure. The percentage of root colonization by AM fungi varied from 13.3% to 100%. Mangifera indica and Morus indica have maximum percentage of colonization (100%). The intensity of root colonization were abundant in the plants belonging to the families Anacardiaceae, Asclepiadaceae, Moraceae, Leguminosae and Apocynaceae whereas the intensity of colonization of crop roots were moderate and poor belonging to Gramineae and Leguminosae. The presence of greater number of spore in soil was always associated with the incidence of abundant mycelia. In plant roots the formation of spore and mycelia was restricted by low pH. Number of mycorrhizal fungus spores ranged between 35 to100 per 100g air dried soil in different family respective soils. The frequency of mycorrhizal fungus infection showed positive correlation with soil pH, moisture, water holding capacity, texture, total nitrogen, organic carbon, phosphorus, calcium, potassium, and magnesium. Especially phosphorus and nitrogen in the soil greatly influenced the plant root infection by AM fungi.     

Phenylalanin Ammonia-lyase Activity,Total Phenolics and Flavonoids Contents in Flowers,Leaves,Hulls and Kernels of Three Pistachio(Pistacia vera L.) Cultivars

Phenylalanin ammonia-lyase (PAL) plays a pivotal role in the production of phenolic compounds, which are responsible for the success of the defense strategies in harsh environments in response to different stimuli. Measurements of the PAL activity, total phenolics, total flavonoids and anthocyanin contents were performed in flowers, leaves and fruits of three pistachio cultivars “Ahmadaghaii”, “Ohadi” and “Kallehghuchi”. The results showed that PAL activity was different in cultivars and in plant organs of pistachio trees (flowers, leaves and fruits). The highest activity rate of their compounds was observed in Ahmadaghaii cultivar. A positive correlation was observed between PAL activity, total phenolics and total flavonoids in leaves, and a negative correlation between PAL activity and anthocyanin contents in leaves and flowers of Ahmadaghaii cultivar. PAL activity and total phenolics in fruits of pistachio suffered a decrease when the maturation processes began. It is suggested that the hulls of the pistachio fruits, containing high level of phenolic compounds (especially in Ahmadaghaii cultivar), may function as a protective layer of defense chemicals against ultraviolet radiation and pathogens. The final concentration of phenolic compounds, flavonoids and antocyanins in the kernel depend on PAL activity in the kernel’s cultivar. The results led to the conclusion that increase in PAL activity, phenolic compounds and flavonoids in Ahmadaghaii can help the plant to cope with the stresses better than the other cultivars. Since phenolic compounds are antioxidant and scavenge free oxygen, it is postulated that Ahmadaghaii is the most resistant cultivar to the environmental stresses.     

Concentration of phenolic compounds of Populus euphratica and soil water contents in Ejina oasis, Inner Mongolia, China

With colorimetric methods, the concentrations of total phenolics, flavonoids and condensed tannins were analyzed in 9 categories of organs in Populus euphratica, including lanceolate leaves, ovate leaves, green branches, branches (D < 5 mm in diameter), branches (5–10 mm in diameter), barks, roots (D < 2 mm in diameter), roots (2–5 mm in diameter) and roots (5–10 mm in diameter). The results showed that phenolic compounds were present throughout the collected organs with the higher total phenolics concentrations in barks (27.93 mg/g), and the mean total phenolics concentrations in two categories of leaves, three classes of roots and three classes of branches were 17.64, 16.72 and 12.19 mg/g, respectively. The higher flavonoids were present in barks (51.30 mg/g), and the mean flavonoid contents in two categories of leaves, three classes of roots and three classes of branches were 28.45, 39.99 and 23.67 mg/g, respectively. The higher condensed tannin contents were found in roots (mean = 22.10 mg/g for three categories of roots), and the average condensed tannin contents in barks, leaves in two categories and branches in three classes were 8.41, 4.03 and 4.47 mg/g, respectively. There was no significant difference between the phenolic compounds of lanceolate leaves and ovate leaves (P > 0.05). Phenolic compounds in branches decreased with the branches maturing, resulting in the following orders: green branches > branches (D < 5 mm) > branches (5–10 mm). Condensed tannins in roots increased with the root diameter decreasing, and the highest condensed tannin contents were found in small roots (D < 2 mm) (25.95 mg/g). By analyzing correlation between phenolic compounds in all collected organs and soil water contents, it was indicated that the phenolic compounds in ovate leaves had negative relation with soil water contents (P < 0.05), and the r values for total phenolics, flavonoids and condensed tannins were –0.949, –0.923 and –0.944, respectively. Data reported here revealed the variation of phenolic compounds in different organs of P. euphratica, and their relationships with the environmental factors in extremely arid areas were discussed.     

Flavonoids from tartary buckwheat induce G2/M cell cycle arrest and apoptosis in human hepatoma HepG2 cells

The cytotoxicity and antioxidant activity on human hepa toma cell line HepG2 of three flavonoids homogenous com pounds from tartary buckwheat seeds and bran, namely quercetin, isoquercetin, and rutin, were investigated. The total antioxidant competency detection results indicated that the antioxidant capacity of quercetin was the strongest in a biological response system. A [3-（4,5-dimethylthiazol-2-yl）-2,5diphenyltetrazolium bromide] assay showed that quercetin exhibited the strongest cytotoxic effects against the HepG2 cell line. Flow cytometric analysis indicated that quercetin significantly increased the production of reactive oxygen species, and led to the G2/M phase arrest accom panied by an increase of apoptotic cell death after 48 h of incubation. Quercetininduced cell apoptosis was shown to involve p53 and p21 upregulation, Cyclin D1, Cdk2, and Cdk7 downregulation. These results suggested that the in duction of G2/M arrest, apoptosis, and cell death by quer cetin may associate with increased expression of p53 and p21, decrease of Cyclin D1, Cdk2, and Cdk7 levels, and generation of reactive oxygen species in cells. This study will help to better understand and fully utilize medicinal resources of plant flavonoids.     

Nitrogen use scenario in India

Nitrogen is one of the major plant nutrients without which the agricultural production is not possible. Nitrogen use in Indian agriculture was nearly 55000 tons in 1950-1951 that increased to 11.31 million tons in 2001 -2002. The total food production of the country has also experienced the similar increase from 50.83 to 222 million tons in the respective years. Interestingly the N fertilizer consumption of India remained almost constant during the last six years indicating the possibility of reducing N consumption. The highest N consumption is in North zone owing to the introduction of rice-wheat cropping system followed by West, South and East. The N use efficiency has been reported to be varying between 30% to 50% depending on the crops and the management. But in most of the cases, N use efficiency has been calculated based on the total N removed by the crops (above ground part only) ignoring the N content left in the roots. It has been observed in controlled experiments that the total N uptake by roots varied from 18% to 44% of the total N removed by the above ground parts, i.e. grain and straw. If the root N is also accounted, the N use efficiency will be higher than reported. The management of other organic sources has to be improved so as to increase the fertilizer use efficiency as well as to check the direct release of N in the atmosphere. In this review all these issues will be dealt.     

Localization and Dynamic Change of Saponin in Vegetative Organs of Polygala tenuifolia

Anatomical, histochemical and phytochemical methods were used to investigate the structure, localization and dynamic changes of total saponin and senegenin of vegetative organs in Polygala tenuifolia Willd. Histochemical localization results showed that saponin accumulated mainly in parenchyma cells of vegetative organs. The phytochemical results also showed that the saponin accumulated in the vegetative organs of P. tenuifolia, with higher content in roots and lower content in the aerial parts that included stems and leaves. The saponin content and dry weight of the vegetative organs of P. tenuifolia had dynamic variance at the developmental stages and all reached the highest level in the post-fruit period. Hence, the roots and aerial parts should be gathered in August to make full use of the plant. As the root is the main medicinal organ of P. tenuifolia, the content of total saponin and senegenin of different aged and different parts of the root were determined. The content of total saponin and senegenin exhibited a sustained decreasing trend with increasing root age; therefore, the annual roots had high quality. The content of total saponin and senegenin in different parts of the root showed obvious variation. The content in the ＂skin areas＂ was much higher than that of xylem. The results offer a theoretical basis for determining the appropriate harvesting stage and a reasonable harvest of P. tenuifolia.     

Mechanisms of salt tolerance in transgenic Arabidopsis thaliana constitutively overexpressing the tomato 14-3-3 protein TFT7

A hydroponics experiment was conducted to investigate the effects of iron plaque on root surfaces with respect to selenite uptake and translocation within the seedlings of two cultivars of rice (Oryza sativa L. cv Xiushui48 and Bing9652). Different amounts of iron plaque were formed by adding 0, 10, 30, 50, 70 mg Fe l⁻¹ in the nutrient solution. After 24 h of growth, the amount of iron plaque was positively correlated with the Fe²⁺ addition to the nutrient solution. These concentrations of Fe, inducing plaque, had no significant effect on the shoot and root growth of rice plants in 50 μg Se l⁻¹ nutrient solution. The amount of Se accumulated in iron plaque was positively correlated to the amount of iron plaque. Increasing iron plaque decreased the selenium concentration in shoots and in roots. At the same time, the translocation of Se from roots to shoots was reduced with increasing amounts of iron plaque. At both the shorter and longer exposure times, the ratio of root- to-shoot selenium was higher than in the controls. More Se stayed in the roots at the longer exposure time than at the shorter time. The concentration of selenium in the xylem sap was sharply decreased with increasing amount of iron plaque on the rice roots. The DCB (dithionite-citrate-bicarbonate)-extracted Se was up to 89.9–91.1% of the total Se when roots with iron plaque (Fe 70) were incubated in 50 μg Se l⁻¹ solution for 30 min. This DCB-extracted Se, however, accounted for only 21.9–28.7% of total Se when roots with iron plaque were incubated in the same solution for 3 days. Se adsorbed in iron plaque can be desorbed by low-molecular-weight organic acids, similar to the desorption of Se from ferrihydrite. These results suggest that iron plaque might act as a ‘buffer’ for Se in the rhizosphere.     

Nutritional Composition and Assessment of Gracilaria lemaneiformis Bory

The chemical composition, mineral elements, vitamins, free fatty acids and amino acid content of the edible red alga Gracilaria lemaneiformis Bory, grown in the sea near Nan＇ao island, Guangdong Province, were analyzed in the present study. Gracilaria lemaneiformis Bory showed a total sugar content of 14.65%. The protein content was 21%, of which approximately 41% was determined to be essential amino acids （EAA）. The major amino acid components were glutamic acid, leucine, arginine, and alanine. Of the EAA assayed, methionine and cysteine appeared to be the most limiting amino acids compared with the EAA pattern provided by Food and Agricultural Organization of the United Nations. The total lipids content was 0.87% and comprised a high composition of unsaturated fatty acids （61%）, mainly as linoleic acid and oleic acid, and a little amount of polyunsaturated fatty acid; palmitic acid was the main component （39%） of saturated acids. Relatively high levels of vitamin C, iodine, phosphorus, and zinc were also present in G. lemaneiformis. The nutritional composition between G. lemaneiformis and Nostoc flagelliforme, a rare alga that is widely eaten in Chinese society, was compared. The results suggest that N. flagelliforme can be substituted for by G. lemaneiformis, not only because of their similar shape, but also because of their approximate nutritional composition. Gracilaria lemaneiformis may possibly serve as a potential healthy food in human diets in the future.     

甘草生物碱成分的分析及含量测定

研究对主要药用甘草即乌拉尔（G.uralensis）、光果甘草（G.inflata）、胀果甘草（G.palliadiflora）、刺果甘草（G.pallidiflora）的根中生物碱成分进行了分析研究。结果表明：生物碱成分为喹啉衍生物类及异喹啉衍生物类,总含量平均为0.29%,此结果为生物碱类药物的生物及甘草的进一步开发利用提供科学依据。     

Genetic characterization and phytochemical analysis of wild and cultivated populations of Scutellaria baicalensis

Scutellaria baicalensis was collected from four wild and four cultivated populations from different locations in China. Forty-two samples were analyzed using random amplification of polymorphic DNA (RAPD) techniques for genetic profiling, and high performance liquid chromatography (HPLC) techniques to determine the flavonoid content. The selected 23 RAPD primers yielded a total of 838 clear and reproducible bands of which 237 were found to be polymorphic. The wild population exhibited higher polymorphism than that of the cultivated population. The dendrogram generated by the UPGMA method via Nei's genetic distance revealed three distinct genotypes from the cultivated populations and several branches from the wild populations. The contents of baicalin and wogonoside in dried roots of the samples ranged from (w/w) 8.63 to 17.84%, and from 1.99 to 4.21%, respectively, whereas their aglycones, baicalein and wogonin, were within the range of only 0.04-0.23%. The total content of the four flavonoids varied from 9.45 to 26.24%. Comparatively, the cultivated populations contained much higher levels of baicalin and total flavonoids than those in the wild populations. The results from genetic characterization and phytochemical analysis demonstrated that the quality variation of this drug was mainly determined by extrinsic environmental or agricultural factors, rather than by genetic differences. Our findings can be used for the commercial production and germplasm management of this medicinal plant.     

不同栽培龄期光果甘草不同部位总黄酮含量的分析

光果甘草(Glycyrrhiza glabra L.)为甘草属(Glycyrrhiza L.)多年生草本植物,是药用甘草的原植物之一[1].甘草属植物所含的黄酮类成分具有抗血栓、抗氧化、抗肿瘤、抗衰老、增加白细胞、抗动脉硬化、抗心律失常和抑制HIV等作用[2-5];光果甘草中的黄酮类成分光甘草定具有良好的抗氧化、抗炎及抗菌作用,应用前景广阔[6].目前关于光果甘草总黄酮含量已有一些报道[7-8],但有关生长年限对栽培光果甘草总黄酮含量的影响却很少报道[9-10],尤其是对不同栽培龄期光果甘草在不同采集时间各部位总黄酮含量的变化规律缺乏较全面的研究,致使光果甘草药材生产缺乏有力的理论指导依据.     

Flavonoids from Glycyrrhiza pallidiflora hairy root cultures

Glycyrrhiza pallidiflora hairy roots were induced from axenic young plants by direct infection with Agrobacterium rhizogenes. The chemical constituents were then investigated after mass culture. The isoflavone, licoagroisoflavone and the coumestan, licoagroside C, were isolated along with seven known flavonoids. Their structures were determined on the basis of spectroscopic evidence.     

迎春花中黄酮类化合物含量的研究

以75％乙醇为溶剂,索氏提取器提取,采用比色法和HPLC法研究了迎春花中黄酮类化合物的含量。以芦丁为对照物,比色法测定出其花、叶、茎中总黄酮的含量分别为13．7％、16．2％、6．77％．RSD分别为2．63％、2．57％、2．96％;以槲皮素、山奈素、异鼠李素为对照物,HPLC法测定出其花、叶、茎中的黄酮总量,以甙元计分别为4．205％、3．371％、1．703％,RSD分别为1．76％、1．58％、1．98％。     

不同居群五柱绞股蓝叶形变异及总黄酮含量分析

以不同生境的五柱绞股蓝为材料,对4个不同来源的五柱绞股蓝的叶片性状、裂叶数进行了统计,并以芦丁为对照品,采用分光光度法对4个居群五柱绞股蓝的总黄酮含量进行了测定。结果表明,五柱绞股蓝的叶型变异较大,其复叶具有3-9裂叶型类型,以7裂叶型和5裂叶型为主。相关性统计显示,野生型五柱绞股蓝黄酮含量高,与7裂叶型极显著相关,家种型五柱绞股蓝黄酮含量低,与叶型无关,环境因子可能是影响其黄酮含量的主要因子。在引种时,7裂叶型的五柱绞股蓝可作为优选资源引用。     

不同繁殖模式下甘草药用成分含量积累速度差异研究

目的:系统比较野生甘草无性繁殖的甘草根和人工甘草种子有性繁殖的甘草根中药用成分的积累速度差异情况,为进一步研究影响甘草药用成分积累的基因机制奠定理论基础。方法:本研究基于HPLC和UV等分析方法,比较野生甘草和人工甘草在甘草酸、甘草苷和甘草总黄酮以及其他类成分的含量差异。基于HPLC指纹图谱技术,全面分析不同繁殖模式下甘草根的化学信息和内在质量的差异情况。结果:除甘草素和异甘草素外,野生甘草不定根中其他三种药用成分和总黄酮的含量均高于人工甘草实生根,经SPSS分析,除异甘草素外,其他成分在两组之间均存在显著差异;根据HPLC指纹图谱,两种甘草药用成分之间差异显著,相似度为0.647。结论:野生无性繁殖的甘草根和人工有性繁殖的甘草根中主要药用成分含量之间存在显著差异,野生甘草具有快速积累药用成分的功能。本研究结果对于今后人工调控生产优质甘草药材,实现甘草资源的可持续利用具有重要的理论和实践意义。     

青海油菜蜂花粉黄酮类化合物含量的研究

采用正交试验设计,研究了青海油菜蜂花粉中黄酮类化合物的最佳提取条件,分别采用HPLC法和比色法测定了黄酮类化合物的含量。最佳提取条件是选用95％的乙醇作为溶剂,以10倍总量的乙醇用量,水浴热回流提取。以槲皮素、山奈酚、异鼠李素为对照品,采用HPLC法,测定出黄酮类化合物平均含量为3．194％;以芦丁为对照物,采用比色法,测定出总黄酮平均含量为3．70％。     

Flavonoids from Glycyrrhiza pallidiflora hairy root cultures

Three flavonoids named licoagrosides D, E and F together with four known flavonoids, medicarpin 3-O-glucoside, calycosin 7-O-glucoside, formononetin 7-O-(6"-malonylglucoside) and 2'-hydroxyformononetin 7-O-glucoside were isolated from Glycyrrhiza pallidiflora hairy root cultures. Their structures were determined on the basis of spectroscopic evidence. Licoagrosides E and F are the first examples of a 6a-hydroxypterocarpan glycoside and an alpha-O-glycosidic alpha-hydroxydihydrochalcone, respectively.