Subjects: Geosciences >> Geography submitted time 2021-04-30 Cooperative journals: 《干旱区科学》
Abstract：Drought was a severe recurring phenomenon in Iraq over the past two decades due to climate change despite the fact that Iraq has been one of the most water-rich countries in the Middle East in the past. The Iraqi Kurdistan Region (IKR) is located in the north of Iraq, which has also suffered from extreme drought. In this study, the drought severity status in Sulaimaniyah Province, one of four provinces of the IKR, was investigated for the years from 1998 to 2017. Thus, Landsat time series dataset, including 40 images, were downloaded and used in this study. The Normalized Difference Vegetation Index (NDVI) and the Normalized Difference Water Index (NDWI) were utilized as spectral-based drought indices and the Standardized Precipitation Index (SPI) was employed as a meteorological-based drought index, to assess the drought severity and analyse the changes of vegetative cover and water bodies. The study area experienced precipitation deficiency and severe drought in 1999, 2000, 2008, 2009, and 2012. Study findings also revealed a drop in the vegetative cover by 33.3% in the year 2000. Furthermore, the most significant shrinkage in water bodies was observed in the Lake Darbandikhan (LDK), which lost 40.5% of its total surface area in 2009. The statistical analyses revealed that precipitation was significantly positively correlated with the SPI and the surface area of the LDK (correlation coefficients of 0.92 and 0.72, respectively). The relationship between SPI and NDVI-based vegetation cover was positive but not significant. Low precipitation did not always correspond to vegetative drought; the delay of the effect of precipitation on NDVI was one year.
Subjects: Geosciences >> Geography submitted time 2021-04-30 Cooperative journals: 《干旱区科学》
Tahani K BAIT SUWAILAM
Abdulrahim M AL-ISMAILI
Nasser A AL-AZRI
L H Janitha JEEWANTHA
Hemesiri KOTAGAMA
Abstract：Seawater greenhouse (SWGH) is a technology established to overcome issues related to open field cultivation in arid areas, such as the high ambient temperature and the shortage of freshwater. It adopts the humidification-dehumidification concept where evaporated moisture from a saline water source is condensed to produce freshwater within the greenhouse body. Various condenser designs are adopted to increase freshwater production in order to meet the irrigation demand. The aim of this study was to experimentally investigate the practicality of using the packed-type direct contact condenser in the SWGH to produce more freshwater at low costs, simple design and high efficiency, and to explore the impact of the manipulating six operational variables (inlet air temperature of the humidifier, air mass flowrate of the humidifier, inlet water temperature of the humidifier, water mass flowrate of the humidifier, inlet water temperature of the dehumidifier and water mass flowrate of the dehumidifier) on freshwater condensation rate. For this purpose, a direct contact condenser was designed and manufactured. Sixty-four full factorial experiments were conducted to study the effect of the six operational variables. Each variable was operated at two levels (high and low flowrate), and each experiment lasted for 10 min and followed by a 30-min waiting time. Results showed that freshwater production varied between 0.257 and 2.590 L for every 10 min. When using Minitab statistical software to investigate the significant variables that contributed to the maximum freshwater production, it was found that the inlet air temperature of the humidifier had the greatest influence, followed by the inlet water temperature of the humidifier; the former had a negative impact while the latter had a positive impact on freshwater production. The response optimizer tool revealed that the optimal combination of variables contributed to maximize freshwater production when all variables were in the high mode and the inlet air temperature of the humidifier was in the low mode. The comparison between the old plastic condenser and the new proposed direct contact condenser showed that the latter can produce 75.9 times more freshwater at the same condenser volume.
Subjects: Geosciences >> Geography submitted time 2021-04-30 Cooperative journals: 《干旱区科学》
Abdulrahim M AL-ISMAILI
Moustafa A FADEL
Hemantha JAYASURIYA
L H Janitha JEEWANTHA
Adel AL-MAHDOURI
Talal AL-SHUKEILI
Abstract：This study aimed to explore the potential of developing a novel cooling system combining a greenhouse and an earth-tube heat exchanger (ETHE). In this system, greenhouse air is circulated through the underneath soil mass to use the deep-soil cooling effect. This was achieved through the following steps. First, soil temperature profile inside and outside the cultivated greenhouse was monitored for almost one year to study the possibility of using deep-soil coldness for cooling the greenhouse air. Second, a prototype ETHE was built to practically investigate the potential reduction in air temperature as the air flows inside the deep earth pipes. Third, a prototype greenhouse was erected to study the ETHE concept. Results from the first experiment revealed that soil temperature at a soil depth of 2.5 m inside the greenhouse offers good conditions to bury the ETHE. The soil temperature at this soil depth was below the maximum temperature (32°C) that most greenhouse crops can withstand. Results from the prototype ETHE showed a slight reduction in air temperature as it passed through the pipes. From the prototype of the integrated greenhouse and ETHE system, reduction in air temperature was observed as the air passed through the ETHE pipes. At night, the air was heated up across the ETHE pipes, indicating that the ETHE was working as a heater. We concluded from this study that greenhouses in arid climates can be cooled using the ETHE concept which would save a large amount of water that would otherwise be consumed in the evaporative coolers. Further investigations are highly encouraged.
Subjects: Geosciences >> Geography submitted time 2021-04-30 Cooperative journals: 《干旱区科学》
Abstract：High temperature and humidity can be controlled in greenhouses by using mechanical refrigeration cooling system such as air conditioner (AC) in warm and humid regions. This study aims to evaluate the techno-financial aspects of the AC-cooled greenhouse as compared to the evaporative cooled (EV-cooled) greenhouse in winter and summer seasons. Two quonset single-span prototype greenhouses were built in the Agriculture Experiment Station of Sultan Qaboos University, Oman, with dimensions of 6.0 m long and 3.0 m wide. The AC-cooled greenhouse was covered by a rockwool insulated polyethylene plastic sheet and light emitting diodes (LED) lights were used as a source of light, while the EV-cooled greenhouse was covered by a transparent polyethylene sheet and sunlight was used as light source. Three cultivars of high-value lettuce were grown for experimentation. To evaluate the technical efficiency of greenhouse performance, we conducted measures on land use efficiency (LUE), water use efficiency (WUE), gross water use efficiency (GWUE) and energy use efficiency (EUE). Financial analysis was conducted to compare the profitability of both greenhouses. The results showed that the LUE in winter were 10.10 and 14.50 kg/m2 for the AC- and EV-cooled greenhouses, respectively. However, the values reduced near to 6.80 kg/m2 in both greenhouses in summer. The WUE of the AC-cooled greenhouse was higher than that of the EV-cooled greenhouse by 3.8% in winter and 26.8% in summer. The GWUE was used to measure the total yield to the total greenhouse water consumption including irrigation and cooling water; it was higher in the AC-cooled greenhouse than in the EV-cooled greenhouse in both summer and winter seasons by almost 98.0%–99.4%. The EUE in the EV-cooled greenhouse was higher in both seasons. Financial analysis showed that in winter, gross return, net return and benefit-to-cost ratio were better in the EV-cooled greenhouse, while in summer, those were higher in the AC-cooled greenhouse. The values of internal rate of return in the AC- and EV-cooled greenhouses were 63.4% and 129.3%, respectively. In both greenhouses, lettuce investment was highly sensitive to changes in price, yield and energy cost. The financial performance of the AC-cooled greenhouse in summer was better than that of the EV-cooled greenhouse and the pattern was opposite in winter. Finally, more studies on the optimum LED light intensity for any particular crop have to be conducted over different growing seasons in order to enhance the yield quantity and quality of crop.
Subjects: Geosciences >> Geography submitted time 2021-04-30 Cooperative journals: 《干旱区科学》
Abstract：Groundwater forms the main freshwater supply in arid and semi-arid areas, and contamination of this precious resource is complicated by the slow rate of recharge in these areas. Nitrate contamination of groundwater is a global water quality problem, as it entails threat to human health as well as aquatic ecosystems. Source identification of contamination is the cornerstone and a prerequisite for any effective management program of water quality. Stable isotope composition of the dissolved nitrate (δ15N-NO3– and δ18O-NO3–) has been applied to identify NO3– sources and the main transformation processes in the upper aquifer system (A1/2, A4, and B2/A7 aquifers) in the Wadi Shueib catchment area, Jordan. Moreover, the stable isotope compositions of the groundwater (δ2H-H2O and δ18O-H2O) in conjunction with the groundwater hydrochemistry were integrated to investigate the origin and evolution of the groundwater. Results revealed that groundwater in the study area is fresh and hard-very hard water, and mainly a Ca-Mg-Cl type. NO3– concentration was in the range of 7.0–74.0 mg/L with an average of 37.0 mg/L. Most of the samples showed concentration higher than the natural background concentration of NO3– (5.0–10.0 mg/L). The δ2H-H2O and δ18O-H2O values indicated that the groundwater is meteoric, and of Mediterranean origin, with a strong evaporation effect. The δ15N-NO3– values ranged between 6.0‰ and 11.3‰ with an average of 8.7‰, and the δ18O-NO3– values ranged between 1.6‰ and 5.9‰ with an average of 3.4‰. These values are in conformity with the stable isotope composition of nitrate derived the nitrification of wastewater/manure, and soil NH4. Nitrification and denitrification are the main transformation processes affecting nitrogen species. Statistical analysis revealed no significant differences in the δ2H-H2O and δ18O-H2O values, and δ15N-NO3– and δ18O-NO3– values for the three aquifers (A1/2, A4, and B2/A7), indicating that the groundwater of these aquifers has the same origin, and a common source of pollution.
Subjects: Geosciences >> Geography submitted time 2021-04-30 Cooperative journals: 《干旱区科学》
Abstract：Snow cover is an important water source for vegetation growth in arid and semi-arid areas, and grassland phenology provides valuable information on the response of terrestrial ecosystems to climate change. The Mongolian Plateau features both abundant snow cover resources and typical grassland ecosystems. In recent years, with the intensification of global climate change, the snow cover on the Mongolian Plateau has changed correspondingly, with resulting effects on vegetation growth. In this study, using MOD10A1 snow cover data and MOD13A1 Normalized Difference Vegetation Index (NDVI) data combined with remote sensing (RS) and geographic information system (GIS) techniques, we analyzed the spatiotemporal changes in snow cover and grassland phenology on the Mongolian Plateau from 2001 to 2018. The correlation analysis and grey relation analysis were used to determine the influence of snow cover parameters (snow cover fraction (SCF), snow cover duration (SCD), snow cover onset date (SCOD), and snow cover end date (SCED)) on different types of grassland vegetation. The results showed wide snow cover areas, an early start time, a late end time, and a long duration of snow cover over the northern Mongolian Plateau. Additionally, a late start, an early end, and a short duration were observed for grassland phenology, but the southern area showed the opposite trend. The SCF decreased at an annual rate of 0.33%. The SCD was shortened at an annual rate of 0.57 d. The SCOD and SCED in more than half of the study area advanced at annual rates of 5.33 and 5.74 DOY (day of year), respectively. For grassland phenology, the start of the growing season (SOS) advanced at an annual rate of 0.03 DOY, the end of the growing season (EOS) was delayed at an annual rate of 0.14 DOY, and the length of the growing season (LOS) was prolonged at an annual rate of 0.17 d. The SCF, SCD, and SCED in the snow season were significantly positively correlated with the SOS and negatively correlated with the EOS and LOS. The SCOD was significantly negatively correlated with the SOS and positively correlated with the EOS and LOS. The SCD and SCF can directly affect the SOS of grassland vegetation, while the EOS and LOS were obviously influenced by the SCOD and SCED. This study provides a scientific basis for exploring the response trends of alpine vegetation to global climate change.
Subjects: Geosciences >> Geography submitted time 2021-04-30 Cooperative journals: 《干旱区科学》
Abstract：Snow avalanches are a common natural hazard in many countries with seasonally snow-covered mountains. The avalanche hazard varies with snow avalanche type in different snow climate regions and at different times. The ability to understand the characteristics of avalanche activity and hazards of different snow avalanche types is a prerequisite for improving avalanche disaster management in the mid-altitude region of the Central Tianshan Mountains. In this study, we collected data related to avalanche, snowpack, and meteorology during four snow seasons (from 2015 to 2019), and analysed the characteristics and hazards of different types of avalanches. The snow climate of the mid-altitude region of the Central Tianshan Mountains was examined using a snow climate classification scheme, and the results showed that the mountain range has a continental snow climate. To quantify the hazards of different types of avalanches and describe their situation over time in the continental snow climate region, this study used the avalanche hazard degree to assess the hazards of four types of avalanches, i.e., full-depth dry snow avalanches, full-depth wet snow avalanches, surface-layer dry snow avalanches, and surface-layer wet snow avalanches. The results indicated that surface-layer dry snow avalanches were characterized by large sizes and high release frequencies, which made them having the highest avalanche hazard degree in the Central Tianshan Mountains with a continental snow climate. The overall avalanche hazard showed a single peak pattern over time during the snow season, and the greatest hazard occurred in the second half of February when the snowpack was deep and the temperature increased. This study can help the disaster and emergency management departments rationally arrange avalanche relief resources and develop avalanche prevention strategies.
Subjects: Psychology >> Other Disciplines of Psychology submitted time 2021-04-30
Abstract： The aesthetic objects arouse aesthetic pleasure that is specific and intense. The Pleasure-Interest of Aesthetic model (PIA) suggests that aesthetic processing is a dual-process including the automatic processing for sensory pleasure and the control processing for aesthetic interest pleasure. Here we review recent work on the neural substrates of aesthetic pleasure. A large body of studies demonstrate that the orbitofrontal cortex is automatically activated by aesthetic objects and different modes of connection with the striatum support different aspects of aesthetic processing. These results consistent with the PIA model. However, the default mode network (DMN) is activated and the lateral prefrontal cortex is deactivated when the aesthetic flow experience occurs, indicating that beyond the dual-process highlighted by the PIA model there is a higher level of aesthetic flow pleasure. We point out that the PIA model needs to be expanded to include this dimension of aesthetic processing and further studies should be conducted on how the aesthetic experience could impact upon creativity and to what extent different aesthetic experiences have the same or differential neural bases for giving rise to aesthetic pleasure.
Peer Review Status:
Awaiting Review
Subjects: Psychology >> Statistics in Psychology submitted time 2021-04-30
Abstract： Abstract: When conducting the multivariate longitudinal studies, reciprocal relationship and latent trajectory are two of the focusing issues. These two issues could be flexibly combined by other research questions, such as the measurement error, the random factor, as well as the combination of the above topics. Such a combination yields a more complex model definition exploring the longitudinal relations, such as factor cross-lagged model, random-intercept cross-lagged model, trait-state-error model, autoregressive trajectory model, etc. In the study, a factor latent curve model with structured reciprocals model was built as an extension and unified framework including all the components discussed above. The empirical dataset, Early Childhood Longitudinal Survey-Kindergarten (ECLS-K), was used as an illustrating example. Results indicated that the trait-state-error model best described the data. Finally, we summarized how the results could be interpreted and offered suggestions on model selection for the researchers. "
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2021-04-29 Cooperative journals: 《天文研究与技术》
Abstract： 使用全球导航卫星系统（GNSS）进行电离层总电子密度（TEC）反演时，单站相对于多站观测网是一种灵活简便的方法。基于人工神经网络，本文提出了一种准实时单站电离层TEC反演的方法。在这种方法中，上一个时段的硬件偏差被作为初值并随着观测值调整，同时电离层TEC也被准实时地反演。为了对这种方法进行详细的评估，通过位于中国的单站，四天磁静日的TEC被分别采用提出的方法与经典的最小二乘球谐函数法反演，其中硬件偏差和TEC的参考值通过附近的多站网得到。在另一个测试中，通过位于欧洲的单站，一次电离层暴事件及前后平静日的TEC也被分别通过上述方法反演。在磁静日，估计的硬件偏差在整体上相对于最小二乘球谐函数法更接近于参考值，反演的TEC也更接近于参考值。电离层暴时，两种方法反演的TEC也具有很好的一致性，神经网络法估计的硬件偏差与磁静日的硬件偏差更接近。结果表明，提出的神经网络法相比最小二乘球谐函数法具有较高的精度。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-04-29 Cooperative journals: 《天文研究与技术》
Abstract：嫦娥四号着陆器搭载的低频射电频谱仪已成功开展观测，每月把观测数据回传到地面，并且把经过一定的预处理后的2C级别的频谱数据释放给了科学团队。本文旨在评估该级别数据是否满足探测宇宙黑暗时代21cm整体谱的要求。我们对生成的2C级别数据进行了长时间积分，并对银河系前景射电辐射被着陆器接收进行了模拟仿真。通过对两套数据进行比对分析，发现2C 数据被减弱40-50 dB，几乎不包含银河系前景的远场辐射信号，这种大幅度的减弱进而影响到了该载荷对宇宙黑暗时代的探测能力。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-04-29 Cooperative journals: 《天文研究与技术》
Abstract：磨损和扭转造成天线俯仰轴结构小尺度变形的快速高精度测量，对修正大口径全可动射电望远镜天线指向精度以及俯仰轴主动健康监测有非常重要的价值。本文提出一种基于虚拟相机的俯仰轴形变测量方法，通过构建单相机测量系统进行数据采集，并建立测量系统数学模型，借助虚拟相机将结构变形转换为虚拟相机空间变换。实验结果表明，该方法在平移分量综合精度可达0.2825mm，旋转分量精度最低可达0.2918o，能够实现俯仰轴1mm尺度变形的快速测量。该系统及其方法具有非接触、精度高、快速性等优点，能满足大口径高频段高精度的射电望远镜俯仰轴长期快速测量需求，也适用于其他大结构小变形测量。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-04-29 Cooperative journals: 《天文研究与技术》
Abstract：为了快速获取副反射面随天线俯仰角变化的位置，并通过调整机构对副面位置进行修正来提高天线综合性能，提出一种虚拟双目视觉测量方法，通过高速相机与平面镜组成的虚拟双目视觉系统对天线观测时副面位置进行模拟实验，获取被测物随实验平台空间移动产生的位置变化图像，并对图像进行预处理、去噪、边缘检测、特征点提取等操作，重建了被测物随实验平台移动而在三维方向上的运动情况，重建结果在三个方向上误差均小于1%，表明该方法具有较高的测量精度，能够较好的对副面位置情况进行重构。
Subjects: Astronomy >> Astrophysical processes submitted time 2021-04-29 Cooperative journals: 《天文研究与技术》
Abstract：日冕抛射物质(Coronal Mass Ejection, CME)是一种强烈的太阳爆发现象，对空间天气和人类生活都有着巨大的影响，因此CME检测对预报CME、保障人类的生产生活安全有重要意义。现有检测方法多采用人为定义特征和人为界定阈值等方法检测CME。由于人为定义特征不能很好表征CME且具有普适性的阈值难于选择，现有CME检测方法对CME的检测效果有待提升。本文提出一种基于Faster R-CNN的日冕抛射物质检测算法。该方法首先结合CDAW、SEEDS、CACTus三个著名CME目录信息，人工标注了包含9113幅日冕图像的数据集，然后根据CME的图像特征较自然图像少、目标尺寸与自然图像有差异等特点，在特征提取和锚点选择方面对Faster R-CNN进行了改进。以2007年6月的CME标注数据为测试集，本文算法检测出了22个强CME事件中的22个和151个弱CME事件中的138个,且对CME事件的中心角和角宽度等特征参数的检测误差分别在5度和10度以内。
Subjects: Biology >> Botany >> Applied botany submitted time 2021-04-29 Cooperative journals: 《广西植物》
Abstract： Ardisia gigantifolia Stapf. is a common Chinese medicinal material in Southwest China, which is widely used in food stewing and medicinal bath. In recent years, the leaves of A. gigantifolia have been developed to make tea, which has effectively broadened the way of application. In order to clarify the nutritional value of A. gigantifolia leaves, we used the national standard method to analyze and evaluate the mineral elements, general nutrients, amino acids and active components of its leaves in different cultivation years, so as to provide scientific basis for its development and utilization. The results were as follows: (1) The leaves of A. gigantifolia contained rich mineral nutrition, which has the characteristics of high potassium and low sodium food. The contents of P, K, Cu, Fe, Mn and Zn in leaves of 1-year-old plants were significantly higher than those of 2-4-year-old plants (P < 0.05). (2) The contents of general nutrients and amino acids of A. gigantifolia leaves were higher. The contents of vitamin C, total sugar and amino acid in leaves of 4-year-old plants were significantly higher than those of 1～3 years old plants (P < 0.05). (3) The leaves of A. gigantifolia were rich in phenols and saponins, but the content of flavonoids was low. The content of total saponins in 1-year-old and total phenolsin 4-year-old were significantly higher than that in other cultivated years (P < 0.05). The mineral nutrition and saponins were the most abundant in 1-year-old, and general nutrition, amino acids andphenols were the most abundant in 4-year-old of A. gigantifolia plants. Compared with common fruits, vegetables and tea, leaves of A. gigantifolia have higher nutritional value and better development and utilization prospects.
Subjects: Biology >> Botany >> Applied botany submitted time 2021-04-29 Cooperative journals: 《广西植物》
Abstract： After Spartina alterniflora was introduced into coastal areas in China, the carbon storage of the original ecosystem was changed after years of growth and succession in the intertidal zone, but the influence mechanism remains to be further studied. In order to further explore the evolution characteristics of organic carbon storage in tidal flat due to S. alterniflora invasion, this study took S. alterniflora wetland in Guangxi Beibu Gulf for about 6 years as the research object, and analyzed the organic carbon and related physical and chemical indexes of samples collected in August, November 2018 and January, March 2019. The results showed that the average annual aboveground carbon storage of S. alterniflora was 9.68 t穐m-2, which was higher than that of underground roots (5.56 t穐m-2). The soil carbon storage of S. alterniflora invasion was significantly higher than that of S. alterniflora plant itself, and the soil carbon storage in spring was significantly higher than that in other seasons. The C / N ratio of soil ranged from 3.53 to 9.67, indicating that the organic carbon of S. alterniflora invasion community was greatly affected by tidal input of sea source. The total carbon storage of S. alterniflora ecosystem was significantly positively correlated with soil carbon storage, and the seasonal variation was consistent. With the extension of invasion time, the organic carbon storage in S. alterniflora ecosystem showed a gradually increasing trend, indicating that the invasion of S. alterniflora increased the organic carbon storage and improved the carbon sequestration capacity in bare flat. This study provides reference for the scientific evaluation of the impact of S. alterniflora invasion on carbon storage in bare flat.
Subjects: Biology >> Botany >> Applied botany submitted time 2021-04-29 Cooperative journals: 《广西植物》
Abstract： Five species of the genus Ranunculus (Ranunculaceae) are described as new from western Sichuan Province. Of them, three new species, R. shimianensis, R. tenuifurcatus and R. perdissectus belong to Sect. Auricomus, one new species, R. ludingensis belngs to Sect. Ranunculus, and the fifth new species, R. filistolonifer, characterized by prostrate and rudiately spreading 10 or more stolons, and 3 petals and 2 stamens per flower, represents a new section. Besides, one variety of R. nephelongenes is described as new too.
Subjects: Biology >> Botany >> Applied botany submitted time 2021-04-29 Cooperative journals: 《广西植物》
Abstract： The impact of Eucalyptus plantations on the ecological environment has been a hot topic of controversy worldwide. The ecological and environmental effects of a mixture of Eucalyptus and precious native tree species have attracted much attention. In order to explore the effects of management measures in mixed plantations on soil nutrients and understory plant functional groups, we assessed the understory plant communities and environmental factors using pure Eucalyptus plantations (PE), mixed Eucalyptus and Castanopsis hystrix plantations (MEC), and pure C. hystrix plantations (PCH). We found significant differences in the physicochemical properties of soil in the different stands. The soil pH, available nitrogen (AN) content, and available phosphorus (AP) content were significantly higher in MEC than in PE and PCH. However, we noted no significant advantages in terms of the soil moisture content (SMC), soil organic carbon (SOC) content, total nitrogen (TN) content, C:N ratio, and C:P ratio in MEC, with a trend of PE < MEC < PCH. On the other hand, the soil bulk density (SBD) and total phosphorus (TP) content showed a trend of PE > MEC > PCH. MEC significantly increased the species richness of the understory woody functional group (WFG), while PCH significantly increased the species richness of the ferns functional group (FeFG). The importance value of WFG and the Gramineae functional group (GFG) was significantly higher in MCH than in PCH, while the importance value of FeFG was significantly higher in PCH than in MCH. Principal coordinate analysis revealed no significant difference in the composition of understory plant functional groups between MEC and PE but revealed a significant difference between MEC and PCH. Moreover, redundancy analysis revealed that AN and AP were the main factors influencing the dominance of WFG. SMC, TN content, and SOC content were the main factors influencing the dominance of FeFG, while SBD was the main factor influencing the dominance of GFG. Thus, the mixture of Eucalyptus and C. hystrix could improve the availability of soil nutrients and the diversity of understory plant communities to some extent in subtropical China.
Subjects: Biology >> Botany >> Applied botany submitted time 2021-04-29 Cooperative journals: 《广西植物》
Abstract： Flavonoid-C- glycosides, as one of the effective components in Premna fulva, have the effect of antigen-induced arthritis. The enrichment and purification process of five flavonoid-C-glycosides as in P. fulva stems is preferred. Through static adsorption and desorption experiments on 13 kinds of macroporous resins with five flavonoid-C- glycosides in P. fulva stems as the index,a suitable macroporous resin was selected, and the results were tested by the HPLC, and then the orthogonal process was used to optimize the enrichment and purification conditions. The results showed that XAD-16N macroporous resin has a good adsorption and desorption effect on the five flavonoid -C-glycosides in P. fulva stems. Through single factor screening and orthogonal process optimization, the best enrichment and purification process is finally determined as follows: the loading concentration is 0.5 times the original extract diluted, the loading flow rate is 2 BV穐-1, and the eluent concentration is 60 % ethanol. The content of five flavonoid-C-glycosides increased from 1.73 % (in the original plant) to 14.5 %, an increase of 7.38 times. The results showed that the selected extraction process is stable and feasible, and the selected macroporous resin has a good separation and purification effect, which provides a reference for the drug development of P. fulva stems.
Subjects: Biology >> Botany >> Applied botany submitted time 2021-04-29 Cooperative journals: 《广西植物》
Abstract： To study the chemical constituents of China endemic plant Rubia oncotricha, the compounds were isolated and purified by silica gel, ODS, Sephadex LH-20, and their structures were elucidated by modern spectroscopic techniques. Fifteen anthraquinone compounds were isolated and identified from Rubia oncotricha, they are 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone-3-O-(6'-O-acetyl)-α-rhamnosyl(1→2)-β-glucoside (1), 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone-3-O-α-rhamnosyl(1→2)-β-glucoside (2), 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone-3-O-(3'-O-acetyl)-α-rhamnosyl (1→2)-β-glucoside (3), 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone-3-O-β-glucoside (4), 1,3,6-trihydroxy-2-hydroxymethyl-9,10-anthraquinone-3-O-(6'-O-acetyl)-β-D-glucopyranoside (5), 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone-3-O-(6'-O-acetyl)-β-D-glucopyranoside (6), physcion-8-O-β-D-glucopyranoside (7), emodin-8-O-β-D-glucopyranoside (8), digiferruginol-11-O-β-gentiobioside (9), 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone-3-O-(6'-O-acetyl)-β-D-xylopyranosyl-(1→2)-β-Dglucopyranoside (10), 6-hydroxyrubiadin (11), 1,2-dihydroxyanthraquinone (12), chrysophanol (13), 6-hydroxyxanthopurpurin (14), 1,3-dihydroxyanthraquinone (15). Compounds 7, 8, 14 are isolated from the genus of Rubia for the first time, compound 1~6, 9, 10, 12, 13 are isolated from Rubia oncotricha for the first time.
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