UV-absorbing compounds and susceptibility of weedy species to UV-B radiation

Stratospheric ozone (O₃) depletion has led to increased terrestrial ultraviolet‐B (UV‐B) radiation (290–320 nm). Leaves exposed to this radiation produce UV‐absorbing compounds in the epidermal cells, which protect plants from UV‐B damage. To determine the role of UV‐absorbing compounds in the UV‐B sensitivity of weeds (common chickweed (Stellaria media), downy brome (Bromus tectorum), green smartweed (Polygonum scabrum), redroot pigweed (Amaranthus retroflexus), spotted cat’s‐ear (Hypochoeris radicata), and stork’s‐bill (Erodium cicutarium)) seedlings were exposed to 0, 4 (field ambient), 7 (18% O₃ depletion) and 11 (37% O₃ depletion) kJ m^?2 d^?1 of biologically effective UV‐B radiation in a greenhouse. Ultraviolet‐absorbing compounds were extracted from the second true‐leaf (0.5 cm² samples) with methanol : distilled water : HCl (79 : 20 : 1) in an 85°C water bath for 15 min, and the absorbance of the extracts measured at 300 nm. The shoot dry biomass was recorded to determine the susceptibility to UV‐B radiation. Common chickweed was the most sensitive and green smartweed the least sensitive weed to UV‐B radiation. The latter accumulated more UV‐absorbing compounds and this accumulation occurred earlier compared with common chickweed. As UV‐B_BE radiation levels increased from 0 to 11 kJ m^?2 d^?1, the green smartweed shoot biomass did not decline. However, the biomass of all five susceptible species declined despite an increase in the UV‐absorbing compounds in response to increased UV‐B radiation. Therefore, formation of a ‘UV‐screen’ in these species is not sufficient to fully prevent UV‐B damage. When the concentration of UV‐absorbing compounds in the six species was plotted against their susceptibility to UV‐B radiation, no relationship was observed. Thus, while the accumulation of UV‐absorbing compounds may be a major factor in the protection of certain species against UV‐B radiation and may offer some degree of defence in other species, it does not explain UV‐B susceptibility differences in weedy species in general.     

Ethyl acetate fraction of flavonoids from Polygonum hydropiper L. modulates pseudorabies virus-induced inflammation in RAW264.7 cells via the nuclear factor-kappa B and mitogen-activated protein kinase pathways

Pseudorabies virus (PRV) infection leads to severe inflammatory responses and tissue damage, and many natural herbs exhibit protective effects against viral infection by modulating the inflammatory response. An ethyl acetate fraction of flavonoids from Polygonum hydropiper L. (FEA) was prepared through ethanol extraction and ethyl acetate fractional extraction. An inflammatory model was established in RAW264.7 cells with PRV infection to evaluate the anti-inflammatory activity of FEA by measuring cell viability, nitric oxide (NO) production, reactive oxygen species (ROS) release, and mRNA expression of inflammatory factors, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). Its functional mechanism was investigated by analyzing the phosphorylation and nuclear translocation of key proteins in the nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Our findings indicate that PRV induced inflammatory responses in RAW264.7 cells, and the responses were similar to that in lipopolysaccharide (LPS)-stimulated cells. FEA significantly suppressed NO synthesis and down-regulated both expression and secretion of COX-2, iNOS, and inflammatory cytokines (P<0.05 or P<0.01). FEA also reduced NF-κB p65 translocation into the nucleus and decreased MAPK phosphorylation, indicating that the NF-κB/MAPK signaling pathway may be closely related to the inflammatory response during viral infection. The findings suggested the potential pharmaceutical application of FEA as a natural product that can treat viral infections due to its ability to mitigate inflammatory responses.     

酸模叶蓼对大豆生长的影响及其经济阈值

酸模叶蓼是大豆田的恶性杂草,严重危害大豆生长发育及产量,为明确酸模叶蓼在大豆田中的经济危害允许水平和经济阈值,在大田条件下采用添加系列试验和拟合函数关系模型的方法,研究了酸模叶蓼与大豆的竞争关系。结果表明,在酸模叶蓼的竞争干扰下,大豆单株荚数,产量均随酸模叶蓼密度的增加而逐渐降低,而株高没有显著变化。线性函数模型y=-0.443x+39.453(R2=0.962,F=75.887,P=0.003)能较好地拟合酸模叶蓼对大豆单株荚数的影响;二次曲线函数模型y=0.702x~2-54.395x+3027.810(R~2=0.972,F=34.843,P=0.028)能较好地拟合大豆产量与酸模叶蓼密度之间的关系,对数函数y=16.131lnx-23.458(R2=0.911,F=20.532,P=0.045)能较好的拟合大豆产量损失与酸模叶蓼密度之间的关系。大豆田酸模叶蓼人工拔除的经济阈值为10.22株/m2,使用75%噻吩磺隆水分散粒剂、80%阔草清水分散粒剂、95%精异丙甲草胺乳油防除的经济阈值分别为4.75、5.03、5.25株/m~2。酸模叶蓼对大豆产量有明显影响,通过对经济阈值分析,在大豆田化学除草剂防治酸模叶蓼具有明显的经济优势。     

新化水酒辣蓼草酒药工艺技术研究

以大米为原料，在酒药制作过程中添加辣蓼草，以糖化力和发酵力为评价指标，通过单因素试验和正交试验，探讨了辣蓼草添加量、种曲添加量、培曲时间对新化水酒酒药品质的影响，筛选出新化水酒辣蓼草酒药的最佳制作工艺条件。结果表明，新化水酒辣蓼草酒药的最佳制作工艺条件为：辣蓼草添加量6%，种曲添加量5%，培曲时间60 h，在此工艺条件下制得的酒药糖化力和发酵力分别为1 443 U/g和53.4 g/100 g。     

何首乌茎尖嫩叶主要营养成分分析及评价

测定了何首乌茎尖嫩叶的VB2、VC、粗纤维等主要营养成分含量和K、Fe、Zn等矿质元素含量,以期为何首乌茎尖嫰叶的合理开发利用提供理论依据。结果表明,何首乌茎尖嫩叶营养丰富,各种营养成分较为全面,其主要营养成分和矿质元素含量也远远高于其他4种常见蔬菜,这为何首乌茎尖嫩叶的食用价值提供了科学依据,也为改善人们的膳食营养和餐饮文化、开发蔬菜资源及提高其利用价值提供了参考。     

虎杖提取物对CCl4诱导建鲤损伤肝细胞生化指标的影响

为探明虎杖对鱼类损伤肝细胞是否具有修复作用，分离建鲤肝细胞，设6个试验组：I组(空白对照组)；II组(CCl4模型组)；III组(800 μg/mL虎杖提取物对照组)；IV组(造模前200、400、800 μg/mL虎杖提取物处理组)；V组(造模后200、400、800 μg/mL虎杖提取物处理组)；VI组(造模前、后200、400、800 μg/mL虎杖提取物处理组)。各组细胞经处理后继续培养12 h，收集肝细胞培养液，检测上清培养液中丙氨酸转氨酶(GPT)、天冬氨酸转氨酶(GOT)、乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)等酶活性，丙二醛(MDA)含量及肝细胞的存活率。结果表明：III组肝细胞培养液中GOT、GPT、LDH、SOD、MDA值及细胞存活率与I组相比无明显变化(P＞0.05)，说明800 μg/mL虎杖提取物没有细胞毒性，可用于后续试验；与II组相比，IV组中800 μg/mL虎杖提取物处理组的效果优于其他2个浓度组，可以极显著降低培养液中GOT值(P<0.01)，显著降低培养液中GPT、LDH值(P<0.05)，显著提高肝细胞的存活率(P<0.05)，而MDA含量和SOD值差异无统计学意义(P＞0.05)；与II组相比，V组中400 μg/mL虎杖提取物效果优于其他2个浓度组，可以极显著降低培养液中GOT值(P<0.01)，显著降低培养液中LDH值(P<0.05)，显著提高肝细胞的存活率(P<0.05)，但GPT值、MDA含量、SOD的差异无统计学意义(P＞0.05)；与II组相比，VI组中800 μg/mL虎杖提取物效果优于其他2个浓度组，能极显著降低培养液中GOT、GPT、LDH在肝细胞中的释放(P<0.01)，显著降低培养液中MDA含量(P<0.05)，显著提高肝细胞的存活率(P<0.05)。综合以上结果，以VI组中800 μg/mL的虎杖提取物效果最好，能有效抑制CCl4所造成的肝细胞损伤，其机制可能与其抗氧化作用有关。     

高寒珠芽蓼草甸植被生物量的季节动态特征

调查了甘肃省天祝县珠芽蓼高寒草甸,结果表明,调查草甸的主要植物有26种,隶属13科23属。其中珠芽蓼(0.148)为优势种,次优势种有乳白香青、球花蒿、线叶嵩草等。通过对珠芽蓼草甸群落组成和结构的季节动态的研究分析发现,地上植物量在整个生长季中表现为单峰曲线,地下植物量变化呈现“V”型曲线,环境因子是制约珠芽蓼草甸植物生长发育和植物量的主导因子。     

不同产地加工方法对何首乌中二苯乙烯苷含量的影响

分别采用晒干、烘干法加工处理不同片型、规格的何首乌药材,采用HPLC法测定其中二苯乙烯苷的含量。以考察不同产地加工方法对何首乌中二苯乙烯苷的影响,为优选何首乌的产地加工方法及优化工艺提供依据。结果表明不同片型、规格何首乌二苯乙烯苷的平均含量依次为100℃烘干≈晒干﹥80℃烘干﹥60℃烘干,随着切片厚度的增加,其含量逐渐减少。可见不同产地加工对何首乌中二苯乙烯苷的含量有影响,其中片型、规格对其影响不显著,干燥方法对何首乌中二苯乙烯苷的影响显著。     

滇中地区何首乌野生生境调查初报

对滇中地区9县(市)16个点野生何首乌的生境进行了调查。结果表明:何首乌广泛分布于滇中地区海拔1400~2100 m及光照强度5000~10000 lx的疏林、灌木丛或路边、田边、土坎上;适于生长在光照充足、空气湿度较大、土壤有机质含量高、质地疏松、保水和排水性良好、土层深厚、微酸到中性的壤土或砂壤土上;稀疏灌木林伴生能保障何首乌正常生长对光照的需求。     

TLC法测定虎杖中白藜芦醇的含量

本文建立了虎杖白藜芦醇含量测定的薄层扫描分析方法：以硅胶G为薄层吸附荆，氯仿：丙酮：乙酸：水(4：4：0．5：0．2)为展开剂，在紫外灯(365nm)下观察荧光斑点，在365n／n处并进行扫描测定，线性方程为：Y=(13．826S’10^-6)-0．8698(Y为白藜芦醇浓度ug／ml，S为峰面积)。并对虎杖茎、根、叶进行了含量测定。结果表明：用TIC法测定虎杖中白藜芦醇含量方法简便、快捷、准确度高、重复性好。虎杖鲜根茎中含量达0．548％。