Constituents of glandular trichomes of Tithonia diversifolia: relationships to herbivory and antifeedant activity

The herbivory activity of the bordered patch larvae (Chlosyne lacinia, Lepidoptera) on leaves of a Brazilian population of Tithonia diversifolia and the antifeedant potential of its leaf rinse extract were investigated. The caterpillars fed only on the adaxial face, where the density of glandular trichomes is very low, and avoided the abaxial face, which contains high levels of trichomes. Deterrent activity against the larvae was observed in leaf discs treated with leaf rinse extract at concentrations of 1-5% of fresh leaf weight. High-performance liquid chromatography (HPLC) analysis indicated that sesquiterpene lactones are the main constituents of the glandular trichomes. Dichloromethane rinse extracts of the leaves and inflorescences were chemically investigated, and 16 compounds were isolated and identified: 14 sesquiterpene lactones, a flavonoid and a diterpenoid. In this study, five sesquiterpene lactones are described for the first time in the genus, including two lactones, one of which has an unusual seco-guaianolide skeleton. Our findings indicate that the caterpillars avoid the sesquiterpene-lactone-rich glandular trichomes, and provide evidence for the antifeedant activity of the dichloromethane leaf rinse extract. In addition, a study of the seasonal variation of the main constituents from the leaf surface throughout a year demonstrated that a very low qualitative but a very high quantitative variation occurs. The highest level of the main metabolite tagitinin C was observed between September and October and the lowest was from March to June, the later corresponding to the period of highest infestation by the larvae.     

植物雅龙果叶抑制ACE活性的研究

为研究植物雅龙果叶子降血压活性,利用HPLC对其50％丙酮．水提取物、正丁醇和水萃取部分及其从正丁醇萃取部分中分离得到的两种单一化合物进行了ACE抑制活性的检测。结果表明上述样品均具有一定的抑制ACE活性,50％丙酮-水提取物、正丁醇萃取部分以及芦丁和咖啡酸的EC50值分别为53、30、4．1、2．2mg／mL。     

Utilization of hydrolytic enzymes for the extraction of ginsenosides from Korean ginseng leaves

This study was performed to measure the amount of ginsenoside content obtained from dried ginseng leaf powder treated with various enzymes, including Ultraflo L. Ultraflo L showed superior results to other enzymes and untreated ginseng leaf in catalyzing the liberation of biological compounds. The total ginsenoside content and metabolites showed the highest levels (406.1 μg/mg and 93.1 μg/mg, respectively) in ginseng leaf extract treated with Ultraflo L (UTGL). In particular, the content of ginsenoside F2 in UTGL was 8.5-fold greater compared to that found in the roots. UTGL showed significantly higher DPPH and ABTS antioxidant activities (2.77 mg/mL and 1.57 mg/mL of IC₅₀ value, respectively) than untreated ginseng leaf. Ginseng leaf treated with Ultraflo L has advantages over untreated ginseng leaf in terms of cost and source availability. These data also suggest that the leaves and stems of ginseng may be used as food resources, functional food materials, and feedstuffs.     

<Emphasis Type="Italic">In vitro</Emphasis> susceptibility of viridans streptococci to leaf extracts of <Emphasis Type="Italic">Mangifera Indica</Emphasis>

The susceptibility of Viridans streptococci to leaf extracts of Mangifera indica was studied on 53 clinical isolates from 39 patients. All the isolates were found to be susceptible to both water and methanol extract of M. indica leaves. Minimum inhibitory concentration (MIC) of methanol extract for all isolates were <50 mg/mL and MIC of water extract for all isolates were <200 mg/mL. Methanol extract was found to have better action against Viridans streptococci than water extract.     

The effect of Smallanthus sonchifolius leaf extracts on rat hepatic metabolism

Smallanthus sonchifolius (yacon), originating from South America, has become popular in Japan and in New Zealand for its tubers which contain beta-1,2-oligofructans as the main saccharides. The plant is also successfully cultivated in Central Europe in the Czech Republic in particular. Its aerial part is used in Japan and in Brazil as a component in medicinal teas; while aqueous leaf extracts have been studied for their hypoglycemic activity in normal and diabetic rats. We have already demonstrated the high content of phenolic compounds in yacon leaf extracts and their in vitro antioxidant activity. In this paper, we present the effects of two organic fractions and two aqueous extracts from the leaves of S. sonchifolius on rat hepatocyte viability, on oxidative damage induced by tert-butyl hydroperoxide (t-BH) and allyl alcohol (AA), and on glucose metabolism and their insulin-like effect on the expression of cytochrome P450 (CYP) mRNA. All the extracts tested exhibited strong protective effect against oxidative damage to rat hepatocyte primary cultures in concentrations ranging from 1 to 1000 microg/ml, reduced hepatic glucose production via gluconeogenesis and glycogenolysis at 1000 microg/ml. Moreover, the effects of the organic fractions (200 and 250 microg/ml) and to a lesser extent, the tea infusion (500 microg/ml) on rat CYP2B and CYP2E mRNA expression, were comparable to those observed with insulin. The combination of radical scavenging, cytoprotective and anti-hyperglycemic activity predetermine S. sonchifolius leaves for use in prevention and treatment of chronic diseases involving oxidative stress, particularly diabetes.     

Anti-Ulcerogenic Effect of Methanolic Extracts from Enicosanthellum pulchrum (King) Heusden against Ethanol-Induced Acute Gastric Lesion in Animal Models

A natural source of medicine, Enicosanthellum pulchrum is a tropical plant which belongs to the family Annonaceae. In this study, methanol extract from the leaves and stems of this species was evaluated for its gastroprotective potential against mucosal lesions induced by ethanol in rats. Seven groups of rats were assigned, groups 1 and 2 were given Tween 20 (10% v/v) orally. Group 3 was administered omeprazole 20 mg/kg (10% Tween 20) whilst the remaining groups received the leaf and stem extracts at doses of 150 and 300 mg/kg, respectively. After an additional hour, the rats in groups 2–7 received ethanol (95% v/v; 8 mL/kg) orally while group 1 received Tween 20 (10% v/v) instead. Rats were sacrificed after 1 h and their stomachs subjected to further studies. Macroscopically and histologically, group 2 rats showed extremely severe disruption of the gastric mucosa compared to rats pre-treated with the E. pulchrum extracts based on the ulcer index, where remarkable protection was noticed. Meanwhile, a significant percentage of inhibition was shown with the stem extract at 62% (150 mg/kg) and 65% (300 mg/kg), whilst the percentage with the leaf extract at doses of 150 and 300 mg/kg was 63% and 75%, respectively. An increase in mucus content, nitric oxide, glutathione, prostaglandin E2, superoxide dismutase, protein and catalase, and a decrease in malondialdehyde level compared to group 2 were also obtained. Furthermore, immunohistochemical staining of groups 4–7 exhibited down-regulation of Bax and up-regulation of Hsp70 proteins. The methanol extract from the leaves and the stems showed notable gastroprotective potential against ethanol.     

Phytogenic compounds from avocado (Persea americana L.) extracts; antioxidant activity,amylase inhibitory activity,therapeutic potential of type 2 diabetes

Diabetes is a worldwide public health disease. Currently, the most effective way to treat diabetes is to mitigate postprandial hyperglycemia by inhibiting carbohydrate hydrolysis enzymes in the digestive system. Plant extracts are rich in bioactive compounds, which can be used in diabetes treatment. This study aims to evaluate the polyphenols content in ethanolic extracts of avocado fruit and leaves (Persea americana Mill.). Additionally, their antioxidant activity using DPPH, while the inhibition ability of α-amylase was examined by reacting different amounts of the extracts with α-amylase compared to acarbose as standard inhibitor. The active compounds were detected in the extracts by LC/MS. The obtained results showed that the leaf extract recorded a significant content of total phenolic compounds compared to the fruit extract (178.95 and 145.7 mg GAE /g dry weight, respectively). The total flavonoid values ??ranged from 32.5 to 70.08 mg QE/g dry weight of fruit and leaves extracts, respectively. Twenty-six phytogenic compounds were detected in leaf and fruit extract by LC/MS. These compounds belong to fatty acids, sterols, triterpenes, phenolic acids, and flavonoids. The antioxidant activity of the extracts is due to the exist of phytogenic compounds, i.e., polyphenols and flavonoids. The antioxidant activity increased in a concentration dependant manner. Avocado fruit extract (1000 µg/mL) scavenged 95% of DPP? while leaf extract rummaged 91.03% of free radicals compared with Vit C and BHT. Additionally, higher α-amylase inhibitory activity was observed in fruit extract than the leaf extract, where the fruit and leaf extract (1000 μg/ml) inhibited the enzyme by 92.13% and 88.95%, respectively. The obtained results showed that the ethanolic extracts of avocado could have a significant impact on human health due to their high content of polyphenols.     

Phytochemical Investigations and In Vitro Bioactivity Screening on Melia azedarach L. Leaves Extract from Nepal

Melia azedarach is a common tree used in the traditional medicine of Nepal. In this work, leaves were considered as source of bioactive constituents and composition of methanol extract was evaluated and compared with starting plant material. Flavonoid glycosides and limonoids were identified and quantified by HPLC-DAD-MSⁿ approaches in dried leaves and methanolic extract, while HPLC-APCI-MSⁿ and GC/MS analysis were used to study phytosterol and lipid compositions. β-Sitosterol and rutin were the most abundant constituents. HPLC-APCI-MSⁿ and HPLC-DAD-MSⁿ analysis revealed high levels of phytosterols and flavonoids in methanolic extract accounting 9.6 and 7.5 % on the dried weight, respectively. On the other hand, HPLC/MSⁿ data revealed that limonoid constituents were in minor amount in the extract <0.1 %, compared with leaves (0.7 %) indicating that degradation occurred during extraction or concentration procedures. The methanol extract was subjected to different bioassays, and antioxidant activity was evaluated. Limited inhibitory activity on acetyl and butyryl cholinesterase, as well as on amylase were detected. Moreover, tyrosinase inhibition was significant resulting in 131.57±0.51 mg kojic acid equivalents/g of dried methanol extract, suggesting possible use of this M. azedarach extract in skin hyperpigmentation conditions. Moderate cytotoxic activity, with IC₅₀ of 26.4 μg/mL was observed against human ovarian cancer cell lines (2008 cells). Our findings indicate that the Nepalese M. azedarach leaves can be considered as valuable starting material for the extraction of phenolics and phytosterols, yielding extracts with possible cosmetic and pharmaceutical applications.     

Action of sisal (Agave sisalana, Perrine) extract in the in vitro development of sheep and goat gastrointestinal nematodes

Active compounds from Agave sisalana with antiparasitic action against gastrointestinal nematodes (GINs) could be an alternative to diversify the range of parasite management methods in the livestock sector. The objective of this study was to evaluate the in vitro action of A. sisalana extract on the development of sheep and goat GINs. The extract, obtained from shredded sisal leaves, was utilized at various concentrations in the egg hatch test (EHT), larval development test (LDT), larval feeding inhibition test (LFIT) and adult motility test (AMT). The LC(50) and LC(95) in the EHT were 6.90 and 24.79 mg/mL, in the LDT were 0.041 and 0.067 mg/mL and in the LFIT were 0.053 and 0.24 mg/mL, respectively, showing a dose-dependent relationship. The development and feeding inhibition on L(1) were both 100% at a dose of 0.12 mg/mL. In the AMT there was 100% inhibition at 75 mg/mL after 24h of exposure. The extract of A. sisalana therefore demonstrated significant action on L(1) at 0.12 mg/mL. So, if part of the A. sisalana extract passes through the animal's gastrointestinal system, this material can have a significant effect on the parasites in the feces. This is an interesting approach because it can drastically reduce the pasture contamination as well as the infection of herds.     

Primula spectabilis Tratt. aerial parts: morphology, volatile compounds and flavonoids

The vacuolar and epicuticular flavonoids and the volatiles of the leaves and parts of flower of P. spectabilis Tratt., an endemic species in the Italian Oriental Alps, were investigated. From a MeOH extract of the leaves two flavone glycosides, 8-C-β-glucopyranosylluteolin 7-O-α-arabinofuranoside (1) and 6-C-α-arabinofuranosylapigenin (2) were isolated, in addition to a flavone and three flavonols already known from species of Primula. From an EtOH extract of leaf exudates, 7,3',4'-tri-O-methylquercetin was obtained. The structures were elucidated on the basis of their 1D 1H- and 13C NMR data and 2D NMR techniques, as well as of HPLC-MS. The volatiles emitted by the leaves were mainly constituted by non-terpene derivatives, followed by comparable proportions of hemiterpens, oxygenated monoterpenes and sesquiterpene hydrocarbons. In flowers, monoterpene hydrocarbons were the most represented chemical class followed by non-terpene derivatives. Different proportions of compounds were found when individual parts of flowers were examined separately; calyx produced a greater proportion (approx. 49.5%) of non-terpenes as its volatile metabolites. P. spectabilis has glandular trichomes in the hyaline margins of the epidermal depressions, distributed on the adaxial leaf blade. Glandular hairs were also present on the corolla. Correlations of phytochemical data with the morphological features of leaf, flower and glandular hair are discussed, and a hypothesis is proposed on the ecological roles of the flavonoids and volatile compounds on the general fitness of the species and cross-pollination strategies.     

山葵树叶提取物在力竭运动大鼠中的抗疲劳机制研究

山葵树叶中含有丰富的矿物质和维生素,体外研究证实山葵树叶提取物具有较好的体外抗氧化活性。然而,山葵树叶提取物在体内的抗氧化和抗疲劳作用尚不明确。本研究分别按照100 mg/kg·bw、200 mg/kg·bw和500 mg/kg·bw的剂量对SD大鼠灌胃山葵树叶提取液4周。研究显示,山葵树叶提取物可以剂量依赖性方式提高大鼠的力竭游泳时间(p<0.05)。山葵树叶提取物可显著降低力竭游泳大鼠血清Lac和BUN水平并升高NEFA水平。山葵树叶提取物可提高大鼠的肝糖原和肌糖原含量。山葵树叶提取物可提高大鼠血清和组织SOD、GSH-Px和CAT水平并降低MDA水平。山葵树叶提取物可上调大鼠肝组织中ORM1、CCR5的m RNA和蛋白水平。本研究表明山葵树叶提取物可有效提高力竭游泳大鼠的抗疲劳能力。山葵树叶提取物的抗疲劳作用与减少乳酸堆积、增加脂肪动员、减少糖原分解、提高抗氧化活性有关。此外,山葵树叶提取物的抗疲劳作用与上调ORM1和CCR5的表达有关。     

Phyto-constituents profiling of Luffa echinata and in vitro assessment of antioxidant,anti-diabetic,anticancer and anti-acetylcholine esterase activities

Luffa echinata Roxb. is one of the neglected medicinal plants. It is an important source of bioactive metabolites and used in several Ayurvedic formulations. In the present analysis, mature leaves and fruits were extracted with acetone, ethanol, acetonitrile, methanol and water. Phytochemicals like total phenolic (TPC), flavonoid (TFC), tannin (TTC), alkaloid (TAC) and terpenoid (TTEC) content were analysed. Further, antioxidant (AOX) activities like 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2,2′-azino-bis-(3-ethyl) benzothiazoline-6-sulfonic acid (ABTS) radical scavenging, metal chelating activity (MC), ferric reducing antioxidant power (FRAP) and phosphomolybdenum assay (PMA) were studied. Highest TPC and TFC (189.57 ± 1.9 mg TAE/g extract, 30.48 ± 0.7 mg CE/g extract, respectively) were reported from acetone extract of the leaves. Ethanolic fruit extract showed the highest TTC (13.79 ± 0.2 mg CE/g extract). Acetone and acetonitrile fruit extract revealed maximum TTEC (602.79 ± 3.5 mg UAE/g extract) and moderate TAC (19.96 ± 0.9 mg GE/g extract), respectively. In AOX, highest DPPH (50.52 ± 0.03 mg AAE/g extract) and ABTS (26.78 ± 0.03 mg TE/g extract) radical scavenging reported in methanolic extract of fruit; however, acetone extract of leaf showed highest FRAP (376.89 ± 1.95 mg Fe(II)/g extract) and PMA (326.54 ± 4.73 mg AAE/g extract). In contrast, aqueous extract of leaf and fruit revealed highest metal chelating activity (41.67 ± 0.49 mg EDTA/g extract). In anti-diabetic studies, acetonitrile extract of leaves and fruits exhibited appreciable inhibition of α-amylase (83.33%) and α-glycosidase (77.42%) enzymes. Similarly, acetyl cholinesterase (AChE) inhibition was highest in water (88.91%) and acetone (81.87%) extracts of leaf and fruits. Fruit extracts showed potent anticancer activity against breast (MCF-7) and colon (HT-29) cancer cell lines (LC₅₀ 329.36 and 385.17 µg/mL, respectively). RP-HPLC analysis revealed highest cucurbitacin B (CuB) (196.24 ± 1.4 mg/g DW), followed by cucurbitacin I (CuI) and cucurbitacin E (CuE) in the fruits (57.14 ± 4.9 and 2.03 ± 0.03 mg/g DW, respectively). RP-HPLC analysis of extracts revealed presence of gallic acid (GA), catechin (CA), vanillic acid (VA), chlorogenic acid (CHLA) and coumaric acid (COA), in which highest GA found in the fruits (1.26 ± 0.07 mg/g DW). Liquid chromatography and mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC–MS) analysis revealed presence of bioactive compounds from various groups. Based on the present findings, it was revealed that the fruit and leaf of L. echinata can be used as potent bioresource for natural antioxidants, anti-diabetic, and anticancer drug.     

Antifungals from forest trees: Usefulness in the control of etiological agents of late season soybean diseases

Septoria brown spot and Cercospora leaf blight are late season diseases caused by Septoria glycines and Cercospora kikuchii, respectively. New antifungals are required against these diseases because the chemical controls currently used have detrimental impacts on wildlife and human health. In this work, 48 extracts originated from the leaves, bark, sapwood or heartwood of four forestry species were assayed by the disc diffusion method against S. glycines and C. kikuchii. Although 18 extracts showed antifungal activity, only 5 were active on both fungal species. The leaf methanolic extract of Blepharocalyx salicifolius showed the lowest minimum inhibitory dose (MID) and the highest diameter of growth inhibition (DI) on both fungal species (MID = 200 μg, DI = 14.2 mm, C. kikuchii; MID = 400 μg, DI = 12.2 mm, S. glycines). Pinocembrin was identified as the main antifungal constituent of the methanolic extract. Both the methanolic leaf extract of B. salicifolius and pinocembrin synergized in vitro the effect of the fungicide difenoconazole. Preventive applications of the extract and the mixture extract + difenoconazole (2.4 mg/mL + 0.006 mg/mL) strongly reduced disease severity generated by S. glycines and C. kikuchii 21 days after inoculation of the soybean plants. This effect was significantly stronger than that generated by difenoconazole. Our results suggest that the application of the methanolic extract of B. salicifolius, alone or in mixture with difenoconazole is a promising strategy to be incorporated in the chemical control of S. glycines and C. kikuchii.     

巨桉不同状态叶片浸提液对萝卜幼苗形态和抗性生理特性的影响

以珍珠岩作为基质,选择4年生巨桉(Eucalyptus grandis)嫩叶(T1)、老叶(T2)、表层凋落叶(T3)、腐解凋落叶(T4)4种状态的叶片,每种状态叶片设置3个浸提液浓度水平[分别称取风干叶片30g、15g和7.5g加入900mL蒸馏水进行浸提,以蒸馏水为对照(CK)],采用水培法研究了不同状态叶片浸提液对萝卜(Raphanus sativus)幼苗形态生长和抗性生理特性的影响。结果显示:(1)巨桉不同状态叶片浸提液显著抑制了萝卜幼苗的根长,其中嫩叶的抑制作用最强,腐解凋落叶抑制作用最弱。(2)各状态叶片浸提液处理后萝卜幼苗中过氧化氢酶(CAT)和过氧化物酶(POD)的活性均呈现升高趋势,嫩叶各浓度处理以及其他状态叶片的高浓度处理下超氧化物歧化酶(SOD)活性升高,而其余浓度处理的SOD活性降低。(3)各状态叶片浸提液处理萝卜幼苗的丙二醛(MDA)含量在低浓度处理时低于CK,其余处理下则高于CK。(4)嫩叶各浓度处理萝卜幼苗的可溶性糖(SS)含量显著高于CK,且随着老叶和表层凋落叶浸提液浓度的升高,幼苗SS含量先升后降,腐解凋落叶各浓度处理下则呈渐增的趋势;而可溶性蛋白(SP)含量则随浸提液浓度的增加而升高,且T2和T3两种状态叶片的各浓度处理与CK差异显著。研究表明,巨桉不同状态叶片浸提液对萝卜幼苗生长和抗性生理产生了强烈的抑制作用,其中以嫩叶最强,老叶和表层凋落叶次之,腐解凋落叶最弱。     

Determination of camptothecins in DMSO extracts of Nothapodytes foetida by direct injection capillary electrophoresis

A rapid capillary electrophoresis procedure was developed for determining the anti-cancer components, camptothecins, in Nothapodytes foetida. The hydrophobic compound was extracted from plant tissue (ca. 1 mL of DMSO for 100 mg of dried plant tissue) with a water-miscible organic solvent, DMSO, at elevated temperature (60 degrees C). The extract was directly injected into the separation capillary (untreated fused silica, 34 cm in length, 75 microm i.d.) and analysed in MEKC mode (369 nm). Within 5 min of migration, camptothecins were successfully separated and quantified by adding organic modifiers to the running buffer (20% DMSO, 90 mm SDS in 10 mm borate buffer, pH 8.60). The linear dynamic range for camptothecin was from 5 to 400 microg/mL. This method was proven to be very suitable for monitoring the amount of camptothecins during the cultivation of the medicinal plant.     

Antioxidant actions of du-zhong (Eucommia ulmoides Oliv.) toward oxidative damage in biomolecules

This study aimed to investigate the antioxidant effect of water extracts of Du-zhong (WEDZ) on oxidative damage in biomolecules such as deoxyribose, DNA, and 2'-deoxyguanosine (2'-dG) as induced by Fenton reaction. The WEDZ used included leaves, raw cortex, and roasted cortex. All of the WEDZ inhibited the oxidation of deoxyribose induced by Fe(3+)-EDTA/H2O2/ascorbic acid in a concentration dependent manner. At a concentration of 1.14 mg/mL, the inhibitory effect of the extracts of leaves, roasted cortex, and raw cortex was 85.2%, 68.0% and 49.3%, respectively. The extract of leaves inhibited the strand-breaking of DNA induced by the Fenton reaction at concentrations of 5 and 10 micrograms/microL. This inhibitory effect was similar to mannitol whereas the extracts of raw cortex and roasted cortex had no inhibitory effect at all. WEDZ also inhibited the oxidation of 2'-dG to 8-OH-2'-dG induced by Fe(3+)-EDTA/H2O2/ascorbic acid. Gallic acid had a prooxidant effect, but trolox and mannitol had an antioxidant effect. The leaf extract had a marked inhibitory effect on Fenton reaction induced oxidative damage in biomolecules. The extract of roasted cortex exhibited modest inhibition while the extract of raw cortex had the least inhibitory effect on oxidative damage in biomolecules. This is in contrast to gallic acid in the same reaction system, whose higher reducing power and weaker chelating ability may contribute to its prooxidant effect. In the present study, leaf extract of Du-zhong had inhibitory effect on oxidative damage in biomolecules. Therefore, drinking of Du-zhong tea (leaf extract) over a long period of time may have anticancer potential.     

红花寄生叶3种溶剂提取物清除自由基活性

采用4种方法测定了红花寄生(寄主桑树)叶的水、80%甲醇和80%丙酮提取物对自由基的清除活性,以芦丁和BHT为对照品。结果表明,3种提取物均具有较强的自由基清除能力,且表现出不同程度的量效依赖关系;在3种溶剂提取物中,80%甲醇提取物清除.OH和O2-.活性最强,半清除率浓度ρ(SC50)分别为0.212、0.139 mg/mL,而80%丙酮提取物则清除DPPH.和ABTS.+活性最强,ρ(SC50)分别为0.198、0.580 mg/mL。此外,3种溶剂提取物经酸水解后,HPLC均检出槲皮素和山奈酚等2种黄酮醇苷元,其含量范围分别为39.90～73.03 mg/g、4.82～9.19 mg/g间。可见,槲皮素及其苷类衍生物是红花寄生清除自由基活性的主要作用成分。     

Infraspecific variation of leaf anatomy in Origanum vulgare grown wild in Greece

The histological components of the leaf were studied in dried herbarium material of the three Origanum vulgare subspecies (subsp. hirtum , subsp. viridulum and subsp. vulgare ) grown wild in Greece. These three, geographically distinct, taxa showed remarkable differences in their leaves. The leaves of subsp. hirtum grown in the Mediterranean climatic zone of Greece are characterized by thick cutinized outer walls of the epidermal cells and a thick mesophyll with highly developed chlorophyllous tissues. Peltate glandular trichomes and stomata are numerous on bom leaf surfaces. The thickness of the mesophyll decreases in the other two subspecies grown in the northern part of the country, where a Continental type of climate occurs. The number of glandular trichomes and stomata also decreases. Besides these differences, a noticeable reduction in the size of the essential oil-accumulating subcuticular chamber of the glandular trichomes and in the number of the peribasal cells, has also been recorded in die plants of subsp. vulgare and viridulum.     

白菜叶片挥发成分多样性及对黑斑病菌孢子萌发的影响

本文选取对白菜黑斑病具有不同抗性的白菜品种甜脆绿、瓢儿白、83-1和优早四号,采用GC-MS联用技术对白菜叶面漂洗物的挥发性化学成分进行分析,并用孢子悬滴培养法测定白菜叶面漂洗物对白菜黑斑病菌孢子萌发的影响.结果表明:当叶面漂洗物浓度＞10 μL时,四种白菜叶面漂洗物对病原菌抑制活性的顺序为:瓢儿白＞甜脆绿＞优早四号＞ 83-1,且各品种漂洗物对黑斑病菌孢子萌发的抑制率存在显著差异.甜脆绿漂洗物中含量最高的挥发性化学成分为2,2,4,6,6-五甲基庚烷(17.15％),瓢儿白、83-1和优早四号漂洗物中含量最高的挥发性化学成分为反-3-己烯醇(15.76％、10.87％、7.21％).根据本实验结果发现,2,2,4,6,6-五甲基庚烷、反-3-己烯醇及仅在感病品种83-1漂洗物中检测到的2,4,6,8-四甲基十一烯和2,4,6-ritert-butyl-4-methyl-2,5-cyclo-hexa-dien-1-one可能与黑斑病菌孢子萌发有关.