A simple method for DNA extraction from mature date palm leaves: impact of sand grinding and composition of lysis buffer

Molecular marker techniques have been widely used for cultivar identification of inbred date palms (Phoenix dactylifera L.; Arecaceae) and biodiversity conservation. Isolation of highly pure DNA is the prerequisite for PCR amplification and subsequent use such as DNA fingerprinting and sequencing of genes that have recently been developed for barcoding. To avoid problems related to the preservation and use of liquid nitrogen, we examined sterile sand for grinding the date palm leaves. Individual and combined effects of sodium chloride (NaCl), polyvinylpyrrolidone (PVP) and lithium chloride (LiCl) with the cetyltrimethylammonium bromide (CTAB) method for a DNA yield of sufficient purity and PCR amplification were evaluated in this study. Presence of LiCl and PVP alone or together in the lysis buffer did not significantly improve the DNA yield and purity compared with the addition of NaCl. Our study suggested that grinding of date palm leaf with sterile sand and inclusion of NaCl (1.4 M) in the lysis buffer without the costly use of liquid nitrogen, PVP and LiCl, provides a DNA yield of sufficient purity, suitable for PCR amplification.     

Quality characteristics of olive leaf‐olive oil preparations

Olive leaf‐olive oil preparations were obtained by vigorous mixing at various levels of addition (5, 10, 15%w/w) of new or mature leaves. After removal of the plant material via centrifugation, quality and sensory characteristics of the preparations were determined. Oxidative stability (120°C, 20 L/h) and DPPH radical scavenging were increased ～2–7 fold depending on the level of leaves used due to enrichment with polar phenols, mainly oleuropein, and a‐tocopherol. The extraction process affected the chlorophyll content and organoleptic traits as indicated by acceptability and preference tests (n = 50). Forty‐four % of the panelists identified a strong pungency in preparations with 15% w/w new leaves. Fifty‐four % of them identified a bitter taste in those with 15% w/w mature leaves, which was attributed to high levels of oleuropein (～200 mg/kg oil). Olive leaf‐olive oil preparations had interesting properties regarding antioxidants present that can attract the interest of a functional product market. Practical applications: The wider use of olive oil and derived products is highly desirable. In this sense, the current study presents data that support introduction to the market of a new specialty olive oil based solely on olive tree products (olive oil and leaves). Thus, in addition to olive oil and olive paste, a new product, that is an olive oil enriched with olive leaf antioxidants, especially oleuropein produced via a “green” technique (mechanical means instead of extraction with organic solvent) can be made available for consumers.     

壳聚糖对桑叶水提液的絮凝工艺研究

运用单因素实验和正交实验,以总黄酮和总多糖含量为指标,对壳聚糖加入量、桑叶水提液质量体积比、药液pH值及水浴温度进行考察,确定壳聚糖对桑叶水提液的最佳絮凝工艺条件为:桑叶水提液质量体积比1∶10(g∶mL)、壳聚糖加入量1.2 mL.g-1、药液pH值6.0、水浴温度35℃、絮凝时间3 h。在此条件下,所得总黄酮和总多糖平均含量分别提高至27.46 mg.mL-1、51.15 mg.mL-1。该方法成本低、生产周期短。     

超声波辅助提取花椒叶总黄酮及其体外抗氧化性研究

以3种溶剂提取花椒叶中总黄酮类化合物,比较其黄酮抗氧化性活性。试验结果表明:水提取花椒叶中总黄酮最佳温度80℃,料液比1:70,时间30 min,功率360 W,总黄酮得率3.51%。乙醇溶液提取花椒中总黄酮最佳温度70℃,乙醇体积分数24%,料液比1:40,时间25 min,功率360 W,总黄酮得率3.30%。丙酮-水(2:1)溶液提取花椒叶黄酮得率为3.53%。水溶液、乙醇溶液、丙酮溶液、VC提取总黄酮的清除DPPH自由基能力IC50分别为24、17.5、7.6、75μg/mL。花椒叶总黄酮具有较强的还原能力和清除DPPH自由基能力,其排序为:丙酮溶液提取总黄酮乙醇溶液提取总黄酮水溶液提取总黄酮VC;对.OH自由基的清除能力排序为:VC丙酮溶液提取总黄酮乙醇溶液提取总黄酮水溶液提取总黄酮。花椒叶总黄酮活性强,是一种值得开发的植物资源。     

蓝莓叶原花青素提取工艺研究

以蓝莓叶为原料,采用超声波提取法提取原花青素,研究蓝莓叶原花青素提取分离工艺。在单因素实验基础上,通过正交实验确定从蓝莓叶中提取原花青素最佳提取工艺条件为:乙醇浓度75%,液料比6:1,超声功率550W,提取温度80℃,提取时间80min;精制过程中,乙醇最佳洗脱浓度为60%。在此工艺条件下,蓝莓叶原花青素提取率达到最大值,即4.17%。红外光谱分析结果表明,蓝莓叶原花青素提取物红外谱图与原花青素A类相近。     

Interrelationships between p-Coumaric Acid, Evapotranspiration, Soil Water Content, and Leaf Expansion

Increasing concentrations of p-coumaric acid applied to (cucumber seedling)–[Cecil A _p soil–sand mixture (or soil)] systems inhibited evapotranspiration (primarily transpiration) and leaf area expansion of cucumber seedlings and increased soil moisture. Higher soil moisture resulting from the inhibition of evapotranspiration lowered soil solution concentrations of p-coumaric acid by 14–40% but did not significantly influence the inhibitory effects of p-coumaric acid on seedlings. Inhibition of evapotranspiration and total leaf area and increases in lowest daily soil water were observed 1–3 d after the first p-coumaric acid treatment, whereas inhibition of absolute and relative rates of leaf expansion was observed within a 24-hr period. Development of the maximum effects of p-coumaric acid required several additional days. Recovery from effects, i.e., return to control levels, after p-coumaric acid depletion from soil solution was a gradual process requiring days for evapotranspiration, lowest daily soil water, and total leaf area, but was slightly faster for leaf area expansion. It appears, at least for short-term studies, that the initial input or treatment concentrations of p-coumaric acid represented a reasonable estimate of dose despite the dynamic nature of soil solution concentrations, and that the lowering of available p-coumaric acid concentrations, associated with the elevation of soil moisture, did not result in a concurrent detectable seedling response. However, increased soil moisture associated with p-coumaric acid treatments of sensitive species suggests a means by which the magnitude of some allelopathic interactions may be modified and resource competition and allelopathy could interact.Electronic Supplementary Material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

超临界CO2萃取烟草中茄尼醇的工艺研究

以烟草为原料,研究了超临界CO2萃取烟草中茄尼醇的过程。考察了萃取压力、萃取温度、萃取时间、CO2流量以及夹带剂浓度和流量等因素对茄尼醇质量收率的影响,并得到了萃取茄尼醇的适宜工艺条件：萃取压力25-35MPa,萃取温度35～45℃,CO2流量2．0～3．0L·min^-1,夹带剂85％乙醇,夹带剂流量0．25～0．35mL·min^-1,萃取时间2h。     

响应面法优化提取麻风树叶多糖工艺研究

针对麻风树叶多糖的超声波辅助提取,首先遥过单因素试验选取影响因素与水平,然后在单因素试验的基础上采用三因素三水平的响应麻分析,依据回归分析确定较优提取工艺条件,结果表明,其较优工艺条件为：提取温度93．6℃,提取时间15．4min,水料比26．2：1mL／g,采用该工艺条件,麻风树叶多糖的提取率达到6．25％。     

液体肥料的应用与发展

介绍了液体肥料及其在叶面喷施、浸种、滴灌、冲施、无土栽培等方面的应用效果。探讨了液体肥料的发展趋势和研究方向,并分析了液体肥料的发展前景。     

赤水绵竹叶黄酮提取工艺方法研究

以芦丁为标准品,以贵州省赤水市绵竹叶为实验对象,对竹叶黄酮的提取进行研究,以乙醇浓度、反应温度、料液比、反应时间为主要考察因素,进行L9（3^4）正交实验,对竹叶黄酮提取条件进行系统研究,确定黄酮最佳提取工艺为乙醇提取浓度75％,反应温度70℃,料液比1：20,反应时间5．5h。