西瓜“化瓜”的防治措施

所谓"化瓜"即在雌花开放后,幼瓜自然萎缩脱落的现象。在正常气候条件下,约有47%的雌花不能坐果,严重影响西瓜早期产量,推迟上市季节。导致化瓜的原因,主要是植株徒长,营养生长和生殖生长失调;种植过密,蔓叶郁蔽,影响光合作用;花期遇阴雨和严重干旱,授粉受精不良。

大棚黄瓜“化瓜”的原因与对策

“化瓜”现象是黄瓜生产上存在的普遍问题,特别是采用塑料大棚等保护地栽培的黄瓜,如果管理不善,化瓜率可达50％以上。那么怎样才能降低黄瓜的化瓜率呢? 1.品种结实能力差引起的化瓜 可通过人工授粉、放蜂等措施提高坐果率。据试验,进行人工授粉刺激子房膨大,可使化瓜率下降70％左右,另外,不同季节、不同栽培方式应选用不同的品种。

瓜蒌薤白半夏汤化裁降低高脂饮食模型小鼠血脂的肠道非靶向代谢组研究

目的考察瓜蒌薤白半夏汤化裁降低高脂饮食模型小鼠血脂过程中小鼠的肠道代谢物变化情况,揭示其中的肠道代谢机制。方法分别选择24只ApoE-/-小鼠及6只C57BL/6J小鼠,以高脂饲料及普通饲料饲食;ApoE-/-小鼠分为高、中、低3个治疗组,分别依据瓜蒌薤白半夏汤化裁14、11、7 g/(kg·d)的剂量进行灌胃;模型组则灌胃等体积0.9%氯化钠溶液。末次给药24 h后处死小鼠,并获得其动脉血及肠道内容物样本,分别检测各组小鼠的血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)及高密度脂蛋白胆固醇(HDL-C),同时以液相色谱-质谱联用仪(LC-MS)测定其肠道内容物的代谢组学变化,对获得的代谢组数据进行主成分分析(PCA),并以R程序获得其中的差异代谢物,再利用MetaboAnalyst等在线数据库对获得的差异代谢物进行功能估计分析。结果瓜蒌薤白半夏汤化裁高剂量组可以显著降低小鼠体内TG、TC及LDL-C水平,同时提升HDL-C的水平(P<0.05)。代谢组学的分析结果显示瓜蒌薤白半夏汤化裁高、中、低剂量组小鼠肠道内容物代谢组差异较大。进一步对正常组、模型组及瓜蒌薤白半夏汤化裁高剂量组3组的肠道代谢物分析后,共识别出13个下调和9个上调的阴离子差异代谢物;15个下调和6个上调的阳离子差异代谢物,功能富集的结果显示上述差异代谢物涉及到的最核心的通路为原胆汁酸生物合成路径(primary bile acid biosynthesis)。结论瓜蒌薤白半夏汤化裁可有效改善高脂血症模型小鼠的血脂异常症状,其可通过调节模型小鼠肠道代谢物的形式降低血脂,其中最重要的代谢通路为原胆汁酸生物合成路径。

The Mediation of Defense Responses of Ginseng Cells to an Elicitor from Cell Walls of Colletotrichum lagerarium by Plasma Membrane NAD(P)H Oxidases

NAD(P)H oxidases were detected in suspension cultured cells of ginseng (Panax ginseng C. A. Meyer). The activities of these enzymes were induced by an elicitor (Cle) extracted from cell walls of Col-letotrichum lagerarium. In addition, Cle induced an oxidative burst and enhanced the synthesis of saponin, activity of phenylalanine ammonialyase (PAL) , accumulation of chalcone synthase (CHS) and the transcription of a hydroxyproline-rich glycoprotein gene ( hrgp ) . Pre-treatments with DPI and quinacrine (two inhibitors of mammalian neutrophil plasma membrane NADPH oxidase) for 30 min prior to Cle addition blocked the NAD(P)H oxidase activity induced by Cle. These inhibitors also inhibited the release of H2C2, the synthesis of saponin, PAL activity and CHS accumulation. Our data revealed homology between plasma membrane NAD(P)H oxidases of mammalian neutrophil cells and ginseng suspension cells. They also indicated that deactivated NAD(P)H oxidases catalysed the release of H2O2 and that H2O2 was functioning as a second messenger stimulating PAL activity, saponin synthesis and hrgp transcription. Elevations of Ca2 + and protein phos-phorylation/dephosphorylation were required for this defense process. We propose that NAD(P)H oxidases mediate the processes of Cle-induced defense responses in ginseng suspensions, and postulate the existence of a signalling cascade including extracellular Cle stimulation, activation of plasma membrane NAD(P)H oxidases, release of H2O2, and the intracellular responses of metabolism and gene transcription in ginseng suspension cells.

Extraction of Water-soluble Polysaccharide from Pumpkin and Its Antioxidant Activity

In this study,an orthogonal experiment was performed to explore the optimal extraction technique of water-soluble polysaccharides from pumpkin.Moreover,the polysaccharides＇ capabilities to scavenge ·OH and DPPH· and their gross reducing power was measured with Vc and BHT as references.In the orthogonal experiment,various factors including temperature,extraction time,solid-liquid ratio,were optimized.The results showed that the polysaccharides extracted from pumpkin are endowed with strong in vitro antioxidant properties.Our study provided references for the extraction of pumpkin polysaccharides and for their use as antioxidants.

A Higher Plant Myosin in Luffa cylindrica: Electron Microscopic Visualization

The molecular structure of a higher plant myosin with two 174 kD heavy chains purified from the tendrils of Luffa cylindrica (L.) Roem. was viewed by electron microscopy. The myosin exhibited actin_activated MgATPase activity and could be recognized immunologically by a monoclonal antibody against the skeletal muscle myosin. Electron micrographs of rotary shadowed images of this protein revealed that it had two heads with size and shape similar to those of the skeletal muscle myosin and a relatively short tail in comparison with the conventional myosin. Luffa tendril actin filaments were also visualized and occasionally other Luffa myosin_like proteins with globular structure at the tail ends were also observed. The structural similarity and immunological cross reactivity with antibodies against muscle myosin demonstrate that the 174 kD Luffa tendril myosin is a double_headed myosin. The possible involvement of myosin_actin interactions in Luffa tendril contact coiling will be the subject of further research.

Comparisons between Phenolic Compounds and Antioxidation of Momordica charantia L. in Different Varieties

[Objective] The aim was to compare contents of free and bound polyphenol and antioxidation of balsam pear in different varieties. [Method] Fourteen varieties of balsam pear were chosen to analyze total contents of free or bound phenol and components of free phenol. FRAP （Freeic reducing/antioxidant power）, DPPH （1,1diphenyl-2-picrylhydrazy）, and ABTS ＋· （2, 2’-azinobis-3-ethylbenzothiazoline-6-sulphonic acid diammonium salt） were used to measure antioxidation and analyze relationship between polyphenol content and antioxidation. [Result] Among the fourteen varieties of balsam pear, free, bound and total phenols were 157.58 -382.92, 6.46 -54 and 175.27 -413.79 mg GAE/100 g DW; coefficients of variance were 23.50% , 61.04% and 21.58%, respectively; free phenol accounted for 91.34% of total phenol and bound phenol accounted for 8.66% ; contents of total flavone for the fourteen varieties were from 8.97 to 18.22 mg CE/100 g DW and the coefficient was at 22.80%; vanillic aldehyde acid, epicatechin and rutin differed in contents among different varieties, which changed in 1.83-9.29, 35.17-114.52 and 0.91-4.53 mg/100 g DW and the coefficients were 43.85%, 26.97% and 33.09%; FRAP antioxidation was at 272.16 -713.32 mg TE/100 g DW and coefficient at 27.67% ; IC 50 of DPPH and ABTS ＋· clearance were 11.43-34.14 and 21.57-119.71 mg GAE/100 g DW and coefficients were at 35.10% and 63.75% , accordingly; content of total phenol was of extremely positive correlation with FRAP （P0.01） and of extremely negative correlation with IC 50 of DPPH and ABTS ＋ · clearance （P0.01）. [Conclusion] Contents of phenolic compounds and antioxidation are of significant genotype differences; and phenolic substance and antioxidation are mainly in free form and phenolic substance is the major basis for antioxidation.

Effects of Exogenous Glycine Betaine on Oxidation Metabolism in Cucumbers during Low-temperature Storage

[Objective] This study aimed to analyze the effects of different concentrations of glycine betaine（GB） on oxidation metabolism in cucumbers under low-temperature stress and to investigate the possible mechanism of low-temperature resistance in cucumber during low-temperature storage. [Method] Cucumber cultivar Zhongnong No.8 was treated with 0, 5, 10 and 15 mmol/L GB solutions for 15 min and stored at 4 ℃. Changes in oxidative metabolism-related parameters were observed. [Result] Increasing exogenous GB concentration could enhance GB content in cucumbers, decline lipoxygenase（LOX） activity, improve peroxidase（POD） and catalase（CAT） activities, remove effectively hydrogen peroxide（H2O2） and reduce the accumulation of malondialdehyde（MDA）. [Conclusion] Treating cucumbers with10 mmol/L GB exhibited the most remarkable effect.

Influence of Different Drying Temperatures on Quality of Balsam Pear Slices

[Objective] The aim was to investigate the effects of different drying temperatures on the physiochemical properties and antioxidant activity of balsam pear slices. [Method] Balsam pear slices were dried at different hot air temperatures, 40, 50, 60, 70 and 80 ℃. [Result] The polyphenols content was highest （2.83 mg/g） in the balsam pear slices dried at 50 ℃, and the flavonoids content was highest （2.584 mg/g） in those dried at 60 ℃. Different drying temperatures had a great impact on the antioxidant capacity of polyphenols in balsam pear. The balsam pear slices dried at 50 ℃ showed the strongest capacity for scavenging DPPH free radicals with IC50 of 0.015 mg/ml, and those dried at 80 ℃ showed the strongest capacity for removing ABTS free radicals with IC50 of 0.0689 mg/ml. [Conclusion] The hot air temperature of 50 ℃ had the least impact on the quality of balsam pear slices.

Ag-induced Efficient Immobilization of Papain on Silica Spheres

Complexation and interaction between silver and amino group were applied to induce an efficient immobilization of papain on silica spheres.Tbe silver nanoparticles were deposited on the silica spheres before p apainwas coupled to the silica spheres. The silica spheres with silver nanoparticles were characterized by high resolution transmission electron microscopy （HR-TEM）, Fournier transform infrared spectroscopy （FT-IR）, and UV-Vis scanning spectrometer. FT-IR spectrum was also used to characterize the immobilized and free papain. Effect of some factors on the activities of the immobilized papain was investigated. It was observed that the coupled yield and relative activity of the papain on Ag/SiO2 were 1.17 and 1.86 times of those on the bare SiO2, respectively. At an optimum concentration of silver, theobserved activity of the immobilized papain was 2.1 timesof that on the bare.silica.In addition, the maximum specific activity of papain immobilized on Ag/SiO2 was 819.9 U·mg·^-1, which is slightly lower than that of the free papain, 906.2 U·mg^-1 . Stability of the immobilized papain was also examined. The resuits indicate that the silver nanoparticles successfully induce a fine immobilization of papain.

Extraction of Pumpkin Polysaccharide by Complex Enzyme Method and Its Antioxidant Research

[Objective] This paper aims to study a new method of extracting pumpkin polysaccharide from pumpkin. Single factor experiments were conducted to examine the effects of extracting time,temperature,the solid-liquid ratio and pH value on the extraction yield of polysaccharide from pumpkin. [Method] The best enzyme ratio and extraction conditions for complex enzymes extraction were determined through orthogonal tests. Scavenging ·OH and O-2 activities of pumpkin polysaccharides were also investigated by salicylic acid and improved self-oxidation of o-pheno methods respectively. [Results] The results showed that the biggest extraction yield of polysaccharide from pumpkin can be got when adding 1% cellulose enzyme,1.5% pectinase,1.0% papain and Na2HPO4-citric acid buffer solution (pH was 4.6),and oscillating for 30 min under water at 40 ℃ with the solid-liquid ratio of 1:30. In addition,pumpkin polysaccharides had a strong activity of eliminating ·OH,but very weak activity to scavenge O-2. [Conclusion] This study provided basic data for research and application of Pumpkin polysaccharide.

Antiaging activity of low molecular weight peptide from Paphia undulate

Low molecular weight peptide (LMWP) was prepared from clam Paphia undulate and its antiaging effect on D-galactose-induced acute aging in rats, aged Kunming mice, ultraviolet-exposed rats, and thermally injured rats was investigated. P. undulate flesh was homogenized and digested using papain under optimal conditions, then subjected to Sephadex G-25 chromatography to isolate the LMWP. Administration of LMWP significantly reversed D-galactose-induced oxidative stress by increasing the activities of glutathione peroxidase (GPx) and catalase (CAT), and by decreasing the level of malondialdehyde (MDA). This process was accompanied by increased collagen synthesis. The LMWP prevented photoaging and promoted dermis recovery and remission of elastic fiber hyperplasia. Furthermore, treatment with the LMWP helped to regenerate elastic fibers and the collagen network, increased superoxide dismutase (SOD) in the serum and significantly decreased MDA. Thermal scald-induced inflammation and edema were also relieved by the LWMP, while wound healing in skin was promoted. These results suggest that the LMWP from P. undulate could serve as a new antiaging substance in cosmetics.

Effect of Pectin, Guar and Carageenan on Quality Parameters and Staling of Gluten Free Pan Bread

The effect of low methyl pectin, guar and K-carrageenan at concentrations of 1, 2 and 3% and their combinations at concentrations of 2 and 3% on quality attributes and staling of gluten free bread was studied. Among investigated samples, control （starch） bread with no added

Dihydrochalcones and phenanthrene derivatives from Fissistigma bracteolatum

Three dihydrochalcones derivatives 1-3, flavone 4 and phenanthrene derivative 5 were isolated, together with 9 known compofinds, from the air-dried root bark of Fissistigma bracteolatum Chatterjee. Their structures were determined by spectroscopic （NMR, MS） and chemical methodologies.

Characterization and Visible Light Photocatalytic Activity of Cucurbit[n]urils/CdS-MoS_(2)

In order to reduce the impact of CdS photogenerated electron-hole recombination on its photocatalytic performance,a narrow band gap semiconductor MoS_(2) and organic macromolecular cucurbit[n]urils(Q[n])were used to modify CdS.Q[n]/CdS-MoS_(2)(n=6,7,8)composite photocatalysts were synthesized by hydrothermal method.Infrared spectroscopy,X-ray diffraction,X-ray photoelectron spectroscopy,field emission scanning electron microscopy,ultraviolet-visible and photoluminescence spectrum were used to characterize the structure,morphology and optical properties of the products,and the catalytic degradation of the solutions of methylene blue,rhodamine B and crystal violet by Q[n]/CdS-MoS_(2) composite catalyst was investigated.The results showed that the Q[n]played a regulatory role on the growth and crystallization of CdS-MoS_(2) particles,Q[n]/CdS-MoS_(2)(n=6,7,8)formed flower clusters with petal-like leaves,the flower clusters of petal-like leaves increased the surface area and active sites of the catalyst,the Q[n]/CdS-MoS_(2) barrier width decreased,the electron-hole pair separation efficiency was improved in the Q[6]/Cds-MoS_(2).Q[n]makes the electron-hole pair to obtain better separation and migration.The Q[6]/CdS-MoS_(2) and Q[7]/CdS-MoS2 have good photocatalytic activity for methylene blue,and the catalytic process is based on hydroxyl radical principle.

Review of Research on Sex Differentiation in Bitter Gourd(Momordica charantia L.)

Bitter gourd,with its narrow genetic background and rich sexual type,is a preferred material to be used to study the gender differentiation of flower buds of monoecious plants.This article is a review of studies on the gender differentiation of flower buds of bitter gourd,from morphology to cytology,from classical genetics to molecular biology,and the mechanism by which it is regulated.The recent rapid development of whole genome sequencing and high throughput sequencing provides a novel approach to the study of the gender differentiation of flower buds of bitter gourd.The study of the gender differentiation of flower buds of bitter gourd can provide references for the regulation of gender differentiation and molecular breeding of bitter gourd.

Immobilization of Papain in Biosflica Matrix and Its Catalytic Property

A novel method was developed for papain immobilization through a biomimetic silicification process induced by papain. By incubating papain in a silica precursor solution, the papain-silica composite formed rapidly and oanain was encansulated. The encansulation efficiency and the recovery activity were 82.60% and 83.09%, re-spectively. Compared with enzymes and biomolecules immobilized in biosilica matrix in the presence of additaonal silica-precipitating species, this papaln encapsulation process, a biomimetic approach, realized high encapsulation efficiency by its autosilification activity under mild conditions （near-neutral pH and ambient temperature）. Fur-thermore, the encapsulated papain exhibits enhanced thermal, pH, recycling and storage stabilities. Kinetic analysis showed that the biomimetic silica matrix did not significantly hinder the mass transport of substrate or the release of product.

Studies on the Antioxidant Potential of Extracts from Unripe Fruit of Carica papaya

The antioxidant activities of the ethyl acetate fraction and aqueous extract of unripe fruit of Carica papaya were compared and investigated in vitro using thiobarbituric reactive species （TBARS） assay, total phenol content, evaluation of reactive oxygen species （ROS） in liver mitochondria, Fe2＋ chelating and 2,2-diphenyl-lpicrylhydrazyl （DPPH） scavenging activities. Both extracts had high antioxidant properties and could inhibit FeE＋ and sodium nitroprusside lipid peroxidation in the liver. Total phenol content of ethyl acetate fraction and aqueous extract were 4.50 ±2.26 and 1.21±3.12 mg/g, respectively. Both extracts had a maximal effect at the lowest concentrations tested （15 μg/mL for ethyl acetate and 150 μg/mL for the aqueous）. Ethyl acetate fraction showed that the highest values of antioxidant activity is probably associated with its high phenolic content, Fe2＋ chelating and DPPH scavenging activities. It is therefore concluded that ethyl acetate fraction and to a less extent the aqueous fractions are potent inhibitor of lipid peroxidation.

Allelopathic Potential of Cucumber Tissues Aqueous Extracts

[Objective]The aim of this study was to explore allelopathic effects of the water-extracted crude of cucumber plant parts on seed germination and seedling growth of lettuce(Lactuca sativa L.),cabbage(Brassica pekinensis L.),radish(Raphanus sativus L.) and scallion(Allium fistulosum L.).[Method]The allelopathic effects of different cucumber tissues aqueous extracts were investigated on lettuce,cabbage,radish and scallion using the water-soluble allelopathic principle by seedling bioassay tests.[Result]The trends of inhibitory effects of different cucumber parts increased with increasing extract concentrations.The inhibition effects and the inhibition rate of three aqueous extracts were more significant on root growth than shoot length.Leaf aqueous extracts represented the most exhibited and root aqueous extracts representing the least inhibitory on seed germination,shoot length and root length of lettuce,cabbage,radish and scallion.[Conclusion]This study had provided basis for allelopathic character of different cucumber plant parts.

Potential of the Integrated Control of Cucumber Root Rot Using Natural, Biological and Chemical Methods

Over the few last years, cucumber （Cucumis sativus L） root rot disease became common and inflicted marked losses to yield in Fayoum. Isolation trails from infected cucumber roots revealed that Thielaviopsis basicola and Fusarium moniliforme were the main cucumber root rot pathogens. The isolation trials from the rhizosphere of healthy cucumber plants revealed that two fungal isolates and four bacterial isolates had antagonistic effects against cucumber root rot fungi. All the tested biocontrol agents reduced the radial growth of all the tested root rots fungi in dual cultures. However, all culture filtrates of the tested biocontrol agent significantly reduced radial growth of all the tested pathogenic fungi, except that T. harzianum. Under field conditions, soil treatment with any of T. harzianum and B. subtilis BI and BF, significantly reduced percentages of infected plants and significantly increased percentages of survived plants and fruit yield compared with the control. Application of the commercial product Harpin protein （Messenger）~ product, as a resistance inducer at 0.3, 0.5 and l g/L significantly reduced the percentage of infected plants under greenhouse and field conditions. Field experiments indicated that the average percentage of infected plants after 90 days significantly decreased. The percentage of the survived plants as well as fruit yield increased by using integrated disease management （IDM） package, including the most effective treatments： tolerant cultivar, Trichoderma harzianum granules formula as soil treatment, Purging cassia plant extract, Harpin protein, and a half dose of Vitavax/thiram comparing with the treatment recommended by the Ministry of Agricultural or applied treatments individually.