Effects of artificial light sources on accumulation of phytochemical contents in hydroponic lettuce

Lettuce is grown in different parts of the world and it is beneficial for health. Light condition is one of the most important environmental factor in regulating growth, development, and phytochemical accumulation in lettuce, particularly when lettuce is produced in a hydroponic system. Due to advances in technologies, artificial light sources have become increasingly capable of providing appropriate quality, intensity, and photoperiod of light in hydroponic lettuce production. This review highlights the progress of current research on the effects of artificial light regulation on growth and phytochemical accumulation in lettuce produced in hydroponic systems.     

Variations of SOC and MBC observed in an incubated brown loam soil managed under different tillage systems for 12 years

To assess changes in organic carbon pools, an incubation experiment was conducted under different temperatures and field moisture capacity (FMC) on a brown loam soil from three tillage practices used for 12 years: no‐till (NT), subsoiling (ST) and conventional tillage (CT). Total microbial respiration was measured for incubated soil with and without the input of straw. Results indicated that soil organic carbon (SOC) and microbial biomass carbon (MBC) under ST, NT and CT was higher in soil with straw input than that without, while the microbial quotient (MQ or MBC: SOC) and metabolic quotient (qCO₂) content under CT followed the opposite trend. Lower temperature, lower moisture and with straw input contributed to the increases in SOC concentration, especially under NT and ST systems. The SOC concentrations under ST, with temperatures of 30 and 35°C after incubation at 55% FMC, were greater than those under CT by 28.4% and 30.6%, respectively. The increase in MBC was highest at 35°C for 55%, 65% and 75% FMC; in soil under ST, MBC was greater than that under CT by 199.3%, 50.7% and 23.8%, respectively. At 30°C, the lower qCO₂ was obtained in soil incubated under NT and ST. The highest MQ among three tillage practices was measured under ST at 55% FMC, NT at 65% FMC and CT at 75% FMC with straw input. These data indicate the benefits of enhancing the MQ; the low FMC was beneficial to ST treatment. Under higher temperature and drought stress conditions, the adaptive capacity of ST and NT is better than that of CT.     

Role of cytokeratin 8 on changes of intestinal epithelial permeability induced by corticotropin-releasing factor

AIM: To investigate the role of cytokeratin 8 (CK8) on the change of intercellular permeability of intestinal epithelial cells induced by corticotropin-releasing factor (CRF). METHODS: The expression levels of CRF receptor 1 (CRFR1) and CRFR2 on human colon adenocarcinoma HT29 cell surface were determined by immunofluorescence staining. After treatment with 100 nmol/L CRF for 72 h, the translocation of FITC-labelled dextran was measured in a Transwell chamber. The structural changes of tight junctions were observed under transmission electron microscope. The expression levels of CK8, and tight junction proteins ZO-1 and occludin were determined by Western blot. The activity of protein kinase C (PKC) was detected by ELISA. Furthermore, the effects of CRF on intestinal epithelial permeability were examined in CK8-silencing HT29 cells, which were constructed by infection with sh-CK8 lentivirus. RESULTS: CRF treatment increased the permeability of FITC-labelled dextran (P<0.05), caused the opening of tight junctions, and induced increased fluorescence intensity of CK8. The expression levels of occludin and ZO-1 were down-regulated (P<0.05). PKC activity was decreased at 1 h after CRF treatment (P<0.05). CRF-induced increase in the permeability and down-regulation of occludin were not blocked by CK8 silencing. Nevertheless,CK8 silencing blocked the effects of CRF regarding the decrease in the expression levels of ZO-1 and the increase in PKC activity (P<0.05). CONCLUSION: CK8 may be involved in CRF-induced increase in intestinal epithelial permeability by inhibiting the activity of PKC, and there may be other signaling pathways involved.     

农田管理措施对滨海盐渍化土壤碳平衡的影响

为研究不同农田管理措施对滨海盐渍土壤碳平衡的影响,通过玉米-小麦轮作试验,研究农田土壤碳收支情况。试验共设6个处理:(1)常规对照(CK),(2)有机肥常量(OF),(3)氮肥增施(NF),(4)秸秆还田(S),(5)有机肥加秸秆(OF+S),(6)免耕(NT)。结果表明,秸秆还田和施用有机肥提高了土壤呼吸的强度,而NT处理的CO_2平均释放量最低,不同处理下土壤呼吸表现为OF+S处理S处理OM处理NF处理CKNT处理。各处理土壤有机碳量随着作物种植年份的增加而逐渐升高,其中OF与NT处理增加最多,而NF处理并没有显著提高土壤的有机碳量。在两季作物收获后,各处理的碳输入均高于碳输出,表现为碳净输入,呈现较强的碳汇特征。S处理和OF处理的碳净输入均显著高于CK,可有效减缓土壤CO_2排放,增加其有机碳的输入。     

Impact of newly introduced perennial bioenergy crops on soil quality parameters at three different locations in W‐Germany

The land areas used for bioenergy crop cultivation are increasing across Europe. For several years now, various perennial crops have been cultivated, including Miscanthus , switchgrass and reed canary grass, and the newly introduced cup plant, giant knotweed, tall wheatgrass, virginia mallow, and wild plant mixtures. We investigated the impact that many of these perennial bioenergy crops (PECs) have on the soil organic C and N pools, microbial properties, and earthworm activity at three different study sites in W‐Germany with varying soil conditions after an experimental period of five years. Silage maize (Zea maize ) in rotation with green rye (Cecale cereale ) or Triticale was used for comparison (= annual energy crops; AEC). The overall intention of this study was to gain insights into the future trends of soil quality with changes in land‐use towards bioenergy production. Our results emphasized that in general, soil quality was improved through the cultivation of perennials. For example, after five years of investigation, the mean soil organic carbon contents increased, on average, by 1–2% at two of the three study sites, the soil microbial biomass increased from 13% (virginia mallow) to 27% (tall wheatgrass) (p < 0.05) compared to AEC treatment and the mean earthworm activity (cast production) was significantly improved in PECs compared to AEC. These trends were mainly found in silty to loamy soils, but the results were slightly different in sandy soils and dry climate conditions. We suggest that this might be traced back to unfavourable growing conditions for perennial crops during the first years of establishment. To our knowledge, this is the first comprehensive field investigation of the impact of these newly introduced perennial crops on soil quality indicators that considers various site‐ and soil‐specific growth conditions.     

高温胁迫下蝴蝶豆的生理响应和耐热性评价

以自然高温胁迫下的11份蝴蝶豆为材料,研究叶片厚度、叶绿素值、叶片含水量、电导率值和丙二醛(MDA)含量等外观和生理指标与对照的差异,隶属函数分析结果表明:在高温胁迫下,材料C4、C6、C11的生长表现较好,在叶绿素含量、质膜透性、叶片含水量、MDA含量中的综合反应均较好,相比其它8个材料具有较好的相对耐高温特性,C1和C5的综合反应较弱,为热敏材料.     

Three decades following afforestation are sufficient to yield δ13C depth profiles

Vertical gradients in stable carbon isotope ratios (δ¹³C) in soil profiles can serve to approximate decomposition of organic matter under field conditions. This study tested the time (0, 30, and ≥ 150 y) required for the development of vertical δ¹³C profiles in topsoil by comparing arable, afforested and continuously forested sites, and showed that three decades following afforestation of former cropland are sufficient to develop distinct δ¹³C depth profiles.     

RF-IC卡门禁系统设计

门禁系统能够给各种需要一定程度管理的场所带来极大的方便.它不仅能制止非法人员的侵入,也可对合法人员的行为时间进行记录,在很大程度上提高了其在安全管理方面的层次,具有较高的现实意义和市场需求.文章主要介绍了RF_IC卡门禁系统,并对系统的总体设计方案作了简要论述.     

不同产地树头菜中维生素C含量的测定

以2%草酸溶液为提取溶剂，超声提取维生素C。在254 nm波长下，以0.05 mol/L磷酸二氢钾∶甲醇(90∶10)为流动相，采用HPLC法，检测出石屏、普洱、西双版纳和建水共4个产地树头菜嫩叶中维生素C含量分别为0.79、1.4、1.5和1.6 mg/g，其中建水产地的维生素C含量最高，石屏产地的含量最低。该方法准确可靠，可作为树头菜中维生素C含量的测定。     

一种简易的花房温湿度无线自动监控系统

花房内的温湿度变化直接影响到花卉的健壮生长,以C8051F330为核心设计一款简易的花房温湿度无线自动监控系统,可对花房内的温湿度进行实时自动监控,当花房内温湿度指标超过设定值时,系统发出声光报警。该系统温度测量范围为-55~125℃,精度为±4℃;相对湿度测量范围为10%~90%,精度为±5%。经测试,系统运行稳定,...