近红外高光谱的活体玉米叶片水分成像研究

无损检测植物叶片水分对植物生理生化研究及灌溉管理和旱情监测等均具有重要意义。利用Gaia Sorter近红外高光谱仪(900～1 700 nm),以不同生育期的60个鲜活玉米叶片为试验材料,对叶肉不同区域的平均光谱及烘干称重法得到的水分含量分别用偏最小二乘法(PLS)及逐步多元线性回归(SMLR)进行建模分析。结果表明,验证集决定系数/标准偏差分别为0.975/1.18和0.980/1.02,均取得较好的预测效果,可实现单个玉米叶片平均含水量的测定;SMLR优选的特征波长(1 406和1 692 nm)建模预测结果表明,利用高通量近红外相机结合滤光片方法实现玉米叶片冠层或高空遥感测量的可行性。同时,进行了叶片不同区域水分含量的成像分析,结果表明,验证集中6个叶片的叶肉与主叶脉区域水分含量的参考均值和预测均值的相关系数均达到0.85以上,预测结果与实际情况相符合。     

The Interaction Vector Model and the Intensity of the Secondary Transition of the Benzene Chromophore in Strained Natural Molecules: Sesamol,Melacacidin, Tetrahydropapaverolin,Renifolin, Pterocarpin,Peltogynol

A method (the New Vector Model : NVM) designed to approach the intensity of the secondary transition of the benzene chromophore with-CH3 and-OR substituents, has been recently published ¹ This method is based on MNDO calculations. It has been applied to strained chromophores with fused rings, ² assuming that it is possible to take into account the incidence of strain on intensity in introducing a strain vector in the vector scheme used to calculate the transition moment vector. In another step it has been derived a much simpler method which avoids the quantum calculations. It can be brought into play using graphically simple vector addition rules. ³ This method is based on a new concept : the interaction vector (underneath, the method is called the Interaction Vector Model : IVM). It has been designed to study alkyl and-OR substituents, since we are mainly involved in the study of natural products and many natural products display such substituents. This IVM has not been designed to take into account the perturbations induced by the strain on intensity. The present work is devoted to the adaptation of the IVM to strained benzene chromophores. It is given several examples on the way it can be used on strained natural molecules.     

农用地土壤As元素与叶片光谱特征关系研究

重金属污染是土壤环境污染中亟待解决的问题之一,重金属通过土壤向植物富集,危及人体健康,对生态环境产生巨大隐患.传统的土壤污染监测以化学方法为主,不仅费时费力且监测范围有限,而基于植被高光谱技术的土壤重金属监测方法能够快速准确地获取土壤重金属含量,突破植被屏障,提高土壤重金属监测效率.近年来,国内外许多学者致力于使用盆栽...     

杜仲叶中总黄酮的醇提工艺

在杜仲叶中总黄酮的提取实验中, 单因素考察了乙醇浓度、提取温度、提取时间等因素的影响趋势,并以正交实验设计优选最佳提取条件,即以12倍量的50% 乙醇,在80 ℃条件下回流提取60 min,重复提取一次,总黄酮得率达3.08%,占固体提取物的31.9%,得率稳定、重现性较好.     

Study of essential element accumulation in the leaves of a Cu-tolerant plant Elsholtzia splendens after Cu treatment by imaging laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS)

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used for the quantitative imaging of Cu and other essential elements (such as K, Mg, Mn, P, S and B) in the leaves of a Cu-tolerant plant Elsholtzia splendens treated with the enriched ⁶⁵Cu isotope tracer (isotope abundance of 89.2%). The leaves (newly formed, fully grown and oldest) were scanned directly with a focused Nd:YAG laser in the laser ablation chamber. The ablated material was transported with argon as carrier gas to a quadrupole-based ICP-MS (ICP-QMS), and the ion intensities of ⁶⁵Cu⁺, ³⁹K⁺, ²⁴Mg⁺, ⁵⁵Mn⁺, ³¹P⁺, ³⁴S⁺ and ¹¹B⁺ were measured by ICP-QMS to study the accumulation of Cu and other elements of interest. Standard reference material NIST SRM 1515 Apple Leaves doped with known concentrations of analytes (from 0.1 to 2000 mg L⁻¹) was measured together with the samples by LA-ICP-MS and was used for the quantification of the analytical data. Notable accumulation of Cu in the newly formed leaves was clearly identified by imaging LA-ICP-MS. The increased isotope ratios of ⁶⁵Cu/⁶³Cu measured by LA-ICP-MS demonstrated the path of Cu uptake and accumulation via the petiole and main veins in the leaves. Cu stress-induced accumulation of K, Mg, Mn, P and S in the newly formed leaves was observed, while B was not significantly affected. In the present study, the concentrations of K, Mg, Mn, P and S were not obviously changed in the fully grown leaves after short-term treatment. Along with the treatment, a visible decrease of K and P was found in the oldest leaves, while other elements were not influenced by Cu stress.     

Enhanced Extraction Efficiency of Flavonoids from Pyrus ussuriensis Leaves with Deep Eutectic Solvents

In this study, deep eutectic solvents (DESs) were synthesized using different ratios of choline chloride (CC) and dicarboxylic acids, and their eutectic temperatures were determined. The DES synthesized using CC and glutaric acid (GA), which showed a higher extraction efficiency than conventional solvents, was used for the extraction of flavonoid components from Pyrus ussuriensis leaves (PUL), and the extraction efficiency was evaluated using the response surface methodology. The flavonoid components rutin, hyperoside, and isoquercitrin were identified through high-performance liquid chromatography (HPLC), equipped with a Waters 2996 PDA detector, and HPLC mass spectrometry (LC-MS/MS) analyses. The optimum extraction was achieved at a temperature of 30 °C using DES in a concentration of 30.85 wt.% at a stirring speed of 1113 rpm and an extraction time of 1 h. The corresponding flavonoid content was 217.56 μg/mL. The results were verified by performing three reproducibility experiments, and a high significance, with a confidence range of 95%, was achieved. In addition, the PUL extracts exhibited appreciable antioxidant activity. The results showed that the extraction process using the DES based on CC and GA in a 1:1 molar ratio could effectively improve the yield of flavonoids from PUL.     

Green Extraction of Forsythoside A,Phillyrin and Phillygenol from Forsythia suspensa Leaves Using a β-Cyclodextrin-Assisted Method

In this study, a green process of β-cyclodextrin (β-CD)-assisted extraction of active ingredients from Forsythia suspensa leaves was developed. Firstly, the optimal process of extraction was as follows: the ratio between Forsythia suspensa leaves and β-CD was 3.61:5, the solid–liquid ratio was 1:36.3, the temperature was 75.25 °C and the pH was 3.94. The yields of forsythoside A, phillyrin and phillygenol were 11.80 ± 0.141%, 5.49 ± 0.078% and 0.319 ± 0.004%, respectively. Then, the structure characteristics of the β-CD-assisted extract of Forsythia suspensa leaves (FSE-β-CD) were analyzed using powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and molecular docking to demonstrate that the natural active products from Forsythia suspensa leaves had significant interactions with the β-CD. Additionally, the loss of forsythoside A from aqueous FSE-CD at 80 °C was only 12%, compared with Forsythia suspensa leaf extract (FSE) which decreased by 13%. In addition, the aqueous solubility of FSE-CD was significantly increased to 70.2 g/L. The EC₅₀ for scavenging DPPH and ABTS radicals decreased to 28.98 ug/mL and 25.54 ug/mL, respectively. The results showed that the β-CD-assisted extraction process would be a promising technology for bioactive compounds extracted from plants.     

Biowaste-Derived,Highly Efficient,Reusable Carbon Nanospheres for Speedy Removal of Organic Dyes from Aqueous Solutions

The current work explores the adsorptive efficiency of carbon nanospheres (CNSs) derived from oil palm leaves (OPL) that are a source of biowaste. CNSs were synthesized at 400, 600, 800 and 1000 °C, and those obtained at 1000 °C demonstrated maximum removal efficiency of ~91% for malachite green (MG). Physicochemical and microscopic characteristics were analysed by FESEM, TEM, FTIR, Raman, TGA and XPS studies. The presence of surface oxygen sites and the porosity of CNSs synergistically influenced the speed of removal of MG, brilliant green (BG) and Congo red (CR) dyes. With a minimal adsorbent dosage (1 mg) and minimum contact time (10 min), and under different pH conditions, adsorption was efficient and cost-effective (nearly 99, 91 and 88% for BG, MG and CR, respectively). The maximum adsorption capacities of OPL-based CNSs for BG were 500 and 104.16 mg/g for MG and 25.77 mg/g for CR. Adsorption isotherms (Freundlich, Langmuir and Temkin) and kinetics models (pseudo-first-order, pseudo-second-order and Elovich) for the adsorption processes of all three dyes on the CNSs were explored in detail. BG and CR adsorption the Freundlich isotherm best, while MG showed a best fit to the Temkin model. Adsorption kinetics of all three dyes followed a pseudo-second-order model. A reusability study was conducted to evaluate the effectiveness of CNSs in removing the MG dye and showed ~92% efficiency even after several cycles. Highly efficient CNSs with surface oxygen groups and speedy removal of organic dyes within 10 min by CNSs are highlighted in this paper.     

Induction of Biosynthesis Antioxidant Molecules in Young Barley Plants by Trioxygen

Young barley plants are a good source of bioactive compounds. This paper presents the effects of gaseous O₃ (trioxygen or ozone) on the biosynthesis of compounds, determining the antioxidant potential of young barley plants. The total content of polyphenols was determined along with their profile, as well as total antioxidant potential and vitamin C content. The highest contents of these compounds were identified in young barley plants exposed to gaseous O₃. The main bioactive compound, representing polyphenols, determined in the examined raw materials was saponarin (isovitexin 7-O-glucoside). The induction of increased biosynthesis of these molecules was directly linked to the modification of the activity of selected enzymes. The increased polyphenol content resulted from the modified activities of polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL). On the other hand, the oxidative effect of ozone on barley plants was reduced, owing to the modified activities of catalases (CAT), glutathione peroxidases (SOD) and guaiacol peroxidase (GPOX). Analysis of the results showed that by applying gaseous O₃ at a dose of 50 ppm for 10 min, the contents of bioactive compounds can be maximised in a residue-free way by activating oxidative stress defence mechanisms.     

Valorization of Phenolic and Carotenoid Compounds of Sechium edule (Jacq. Swartz) Leaves: Comparison between Conventional,Ultrasound- and Microwave-Assisted Extraction Approaches

Chayote leaves are known for culinary and traditional medicine applications. This work intended to recover carotenoids and phenolic compounds from chayote leaves using the ultrasound-assisted extraction (UAE). A Box–Behnken design was employed to investigate the impact of extraction time, temperature, and ultrasonic power on the recovery of total carotenoids, total phenolic compounds, and antioxidant activities. For comparative purposes, chayote leaf extracts were prepared by maceration (ME) and microwave-assisted extraction (MAE), using the same time and temperature conditions optimized by UAE. Extraction at 50 °C and 170 Watts for 30 min provided the optimal UAE conditions. UAE showed better extraction efficacy than ME and MAE. The HPLC analysis of the extracts showed that the xanthophyll class was the main class of carotenoids, which constituted 42–85% of the total carotenoid content, followed by β-carotene and tocopherol. Moreover, 26 compounds, classified as phenolic acids, flavonols, flavonoids and other polar compounds, were identified in the chayote leaf extracts. Flavonols accounted for 55% of the total compounds quantified (the major compound was myricetin) and phenolic acids represented around 35%, mostly represented by ferulic acid, chlorogenic acid and (+)-catechin. This study revealed the potential of UAE as an effective green extraction technique to recover bioactive compounds from chayote leaves, for food, and for pharmaceutical and cosmetic applications.