Histochemical Localization of Citral Accumulation in Lemongrass Leaves (Cymbopogon citratus(DC.) Stapf., Poaceae)

Lemongrasses (Cymbopogonspp., Poaceae) are a group of commerciallyimportant C₄tropical grasses. Their leaves contain up to 1.5%(d.wt) essential oils with a typical lemon-like aroma, consistingmainly of citral (a mixture of the isomeric acyclic monoterpenealdehydes geranial and neral). To specifically locate the sitesof citral accumulation in lemongrass we employed Schiff's reagent,which reacts with aldehydes and gives a purple-red colorationwith citral. Using this technique, single oil-accumulating cellswere detected in the adaxial side of leaf mesophyll, commonlyadjacent to non-photosynthetic tissue, and between vascularbundles. Cell walls of these oil cells are lignified. Our resultssuggest that citral accumulation takes place in individual oilcells within the leaf tissues.Copyright 1998 Annals of BotanyCompany Lemongrass;Cymbopogon citratus; Poaceae; oil cells; histochemistry; citral; aldehydes; Schiff's-reagent.     

Essential Oil Gland Number and Ultrastructure During Mentha arvensis Leaf Ontogeny

Alterations in essential oil gland number, distribution and fine structure, and the oil content in the leaf of Mentha arvensis L. were examined during its growth and senescence. Accumulation of essential oil occurred predominantly during the rapid leaf expansion phase followed by a similar decline. The oil gland (trichome) number increased upto leaf maturation and declined thereafter. Initially, cuticle remains tightly apposed to the secretory head of oil glands but progressively a sub-cuticular space appears to be created for the oil. Considerable enlargement of vacuole with ageing is witnessed, whereas cytoplasm gradually decreases to a thin peripheral layer. Some secretory cells from senescing leaf were found almost empty, having only a few remnant oil droplets. This revised version was published online in June 2006 with corrections to the Cover Date.     

Rapid propagation of lemongrass (Cymbopogon flexuosus (Nees) Wats.) through somatic embryogenesis in vitro

Somatic embryos induced from callus cultures of lemongrass [Cymbopogon flexuosus (Nees) Wats.] on Murashige and Skoog medium supplemented with 5 mg/l of 2,4-D, 0.1 mg/l of NAA and 0.5 mg/l of Kn developed into plantlets when plated on a medium supplemented with 3 mg/l of BA, 1 mg/l of GA₃ and 0.1 mg/l of NAA. The regeneration potential of callus was retained for more than 2 years on the nutrient medium supplemented with comparatively lower levels of growth regulators (2,4-D at 2 mg/l, NAA at 0.1 mg/l and Kn at 0.25 mg/l). Approximately 30–35 plantlets were produced after two months of culture per 100 mg of callus inoculated. Regenerants were transplanted into soil and transferred to the field for assessment of various morphological and biochemical characteristics. The results of 1 year of field trials showed that plants derived from somatic embryoids were more uniform in all the characteristics examined when compared with the field performance of plants raised through slips by standard propagation procedures. Thus, a procedure has been developed for high frequency long term plant production of lemongrass through in vitro methods.Abbreviations 2,4-D 2,4 -dichlorophenoxyacetic acid - NAA -naphthalene acetic acid - Kn kinetin - BA benzyladenine - GA₃ gibberllic acid - MS Murashige and Skoog (1962) basal medium     

Ethanol and High-Value Terpene Co-Production from Lignocellulosic Biomass of Cymbopogon flexuosus and Cymbopogon martinii

Cymbopogon flexuosus, lemongrass, and C. martinii, palmarosa, are perennial grasses grown to produce essential oils for the fragrance industry. The objectives of this study were (1) to evaluate biomass and oil yields as a function of nitrogen and sulfur fertilization, and (2) to characterize their utility for lignocellulosic ethanol compared to Panicum virgatum (switchgrass). Mean biomass yields were 12.83 Mg lemongrass ha^-1 and 15.11 Mg palmarosa ha^-1 during the second harvest year resulting in theoretical biofuel yields of 2541 and 2569 L ethanol ha^-1 respectively compared to reported 1749–3691 L ethanol ha^-1 for switchgrass. Pretreated lemongrass yielded 198 mL ethanol (g biomass)^-1 and pretreated palmarosa yielded 170 mL ethanol (g biomass)^-1. Additionally, lemongrass yielded 85.7 kg essential oil ha^-1 and palmarosa yielded 67.0 kg ha^-1 with an estimated value of USD $857 and $1005 ha^-1. These data suggest that dual-use crops such as lemongrass and palmarosa may increase the economic viability of lignocellulosic biofuels.     

蕈树叶芳香精油成分分析及其抗氧化活性研究

为了解蕈树叶芳香精油化学组分及抗氧化活性,采用气相色谱-质谱联用技术(GC-MS)结合Kovats保留指数(K I)比较的方法对其进行了成分分析,并运用二种体外方法对其抗氧化活性进行了测定。结果表明蕈树叶精油以倍半萜烯类为主(占62.39%),主要特征成分为双环大根香叶烯(10.71%)、(E)-丁香烯(9.96%)和α-依兰油烯(8.92%)。该精油具有中等程度的自由基清除活性和抗脂质过氧化活性。其抗氧化活性可能与精油中的酚类物质5-羟基白菖莆烯(2.97%)以及醇类物质1-表橙椒醇(3.12%)和(Z)-白檀油烯醇(2.12%)等化合物有关。     

Starch Mobilization in Ultradried Seed of Maize (Zea mays L.) During Germination

The effects of ultradry storage on the starch mobilization in maize (Zea mays L.) seed after aging were investigated. The results indicated that there were no significant differences in the content of ATP,starch, and soluble sugar, as well as the activity of amylase, between ultradried seeds and seeds stored at -20 ℃ during germination. These results were consistent with the higher level of vigor of the ultradried seed. Sieve tube introduction of a fluorescence dye (carboxyl fluoresceindiacetate) and laser confocal microscopy were used to study the development of plasmodesmata in the ultradried seeds. The results indicated that plasmodesmata developed well in ultradried seeds. Fluorescence analysis also showed that the fluorescence intensity in the radicle of ultradried seeds was stronger than that in seeds with a higher moisture content. This suggests that ultradry treatment has no adverse effects on the seeds. After seed imbibition, cell orgaelles could be resumed. It is concluded that ultradry seed storage is beneficial for maintaining seed vigor and that starchy mobilization proceeds regularly during germination.     

芫荽茎叶精油的消除DPPH自由基作用

用GC-MS对超声波法提取的芫荽茎叶精油成分进行了分析,检测出154个成分,解析出70种物质,占精油93．643％,含量最多的是酯类化合物47．569％,其次为饱和与非饱和烃类化合物19．897％,醛类化合物和醇类化合物含量分别为13．406％,12．595％。探讨了精油对DPPH的清除作用,结果显示,用超声波萃取法获得的精油对DPPH自由基（1,1-diphenyl-2-picrylhydrazyl）具有一定的消除作用,最高消除率62．9％,水蒸汽蒸馏法获得的芫荽茎叶精油的DPPH自由基清除率最大为84．2％。     

Phytoremediation of metals using lemongrass (Cymbopogon citratus (D.C.) Stapf.) grown under different levels of red mud in soil amended with biowastes

Due to hostile condition of red mud (RM), its utilization for vegetation is restricted. Therefore, RM with biowastes as soil amendment may offer suitable combination to support plant growth with reduced risk of metal toxicity. To evaluate the effects of RM on soil properties, plant growth performance, and metal accumulation in lemongrass, a study was conducted using different RM concentrations (0, 5, 10, and 15% w/w) in soil amended with biowastes [cow dung manure (CD) or sewage-sludge (SS)]. Application of RM in soil with biowastes improved organic matter and nutrient contents and caused reduction in phytoavailable metal contents. Total plant biomass was increased under all treatments, maximally at 5% RM in soil with SS (91.4%) and CD (51.7%) compared to that in control (no RM and biowastes). Lemongrass acted as a potential metal-tolerant plant as its metal tolerance index is >100%. Based on translocation and bioconcentration factors, lemongrass acted as a potential phytostabilizer of Fe, Mn, and Cu in roots and was found efficient in translocation of Al, Zn, Cd, Pb, Cr, As, and Ni from roots to shoot. The study suggests that 5% RM with biowastes preferably SS may be used to enhance phytoremediation potential of lemongrass.     

滇西香茅挥发油的化学成分

滇西香茅(Cymbopogon khasiamus(Hack.)Stapf ex Bor)为禾本科植物,分布于印度及缅甸,该植物过去在中国无分布记载,作者在云南首次发现。其挥发油为主要有效成分,当地与芸香草(Cymbopogon distans(Steud)Wats.)混用。为合理开发和利用该种植物,对挥发油的化学成分进行了分析。     

Fungicidal and anti-aflatoxigenic effects of the essential oil of Cymbopogon citratus (DC.) Stapf. (lemongrass) against Aspergillus flavus Link. isolated from stored rice

AIMS: To develop a natural fungicide against aflatoxigenic fungi, to protect stored rice, using the essential oil of lemongrass. METHODS AND RESULTS: Aspergillus flavus Link. was isolated from stored rice and identified as an aflatoxigenic strain. Lemongrass oil was tested against A. flavus and the test oil was fungistatic and fungicidal against the test pathogen at 0.6 and 1.0 mg ml(-1), respectively. Aflatoxin production was completely inhibited at 0.1 mg ml(-1). The results obtained from the thin layer chromatographic bioassay and gas chromatography indicated citral a and b as the fungicidal constituents in lemongrass oil. During the fumigant toxicity assay of lemongrass oil, the sporulation and the mycelial growth of the test pathogen were inhibited at the concentrations of 2.80 and 3.46 mg ml(-1), respectively. CONCLUSION: Lemongrass oil could be used to manage aflatoxin formation and fungal growth of A. flavus in stored rice. SIGNIFICANCE AND IMPACT OF THE STUDY: Currently, fungicides are not used to control fungal pests or mycotoxin production on stored rice. Rice treated with the essential oil of lemongrass could be used to manage fungal pests as well as the insect pests in stored rice. The essential oil is chemically safe and acceptable to consumers, as synthetic chemical fungicides can cause adverse health effects to consumers.     

草麻黄雌性生殖器官的个体发生和畸形式样研究

用扫描电镜观察并分析了草麻黄（Ephedra sinica Stapf)雌性生殖器官的个体发生及畸形式样。该种雌球花个体发生式样与麻黄属其他具双胚朱球果的类群基本一致。外珠被以一对近轴侧突起物出现以及该突起物与苞片成交互排列的发育式样支持前人关于该构造叶性本质的论述,而内珠被与珠心的发育相关,因此可能是真正的珠被,基于返祖性畸形三胚珠球花的出现及其他形态特征,认为麻黄属胚珠数目减少是该属内物种特化的一个趋势;利用雌球花发育的畸形现象及外珠被的形态学本质提出麻黄属的雌球果为复轴性构造,雌性生殖单位是由类似于科达类的次级生殖枝构造经系统发育变态,融合,简化成现存的生胚珠构造式样,每一可育苞片及其腋内雌性生殖单位共同组成了麻黄属的苞鳞－种鳞复合体。     

芙蓉菊挥发油的成分分析

用水蒸气蒸馏法提取芙蓉菊全草中的挥发油,GC-MS分析其化学组成。共检测出232个成分,归一化法分析各成分的相对含量。联机检索鉴定了56个化合物,占挥发油总量的62.59%,主要成分异石竹烯(Isocaryophyllene)的含量高达14.94%。     

侧柏叶精油的抗细菌和抗氧化活性(英文)

采用水蒸气蒸馏法提取侧柏叶精油,通过GC和GC-MS分析精油的组成。从侧柏叶精油中鉴定出29种成分,主要为单萜和倍半萜,含量较高的化合物有:8-丙氧基-柏木烷(15.41%)、松油烯-4-醇(12.98%)、α-蒎烯(9.85%)、桧烯(9.92%)和3-蒈烯(6.77%)。侧柏叶精油具有广谱的抗细菌活性,对供试细菌的最低杀菌浓度(MBC)在0.1 mg/mL和1.0 mg/mL之间,最低抑菌浓度(MIC)在0.063 mg/mL和0.90 mg/mL之间,半抑制浓度(IC50)在0.044 mg/mL和0.763 mg/mL之间。侧柏叶精油能有效抑制菲啰嗪与Fe2+的螯合(IC50值为0.409mg/mL)和β-胡萝卜素-亚油酸的氧化(IC50值为0.526 mg/mL)。     

Leaf Starch Metabolism during the Growth of Pepper (Capsicum annuum) Plants

Levels of starch and sugars, and the activities of amylase and starch phosphorylase were measured in expanding leaves harvested in early morning and early evening during the growth of pepper (Capsicum annuum L.; cv `Bellboy') plants. The differences between starch levels 1 hour after dawn and 1 hour after dusk increased during the period of initial fruit expansion. This diurnal starch difference was strongly correlated with post-dusk amylase activities in leaves at both stages of expansion. There was also a strong correlation between levels of amylase in immature and those in mature leaves throughout the experiment. Phosphorylase activity showed no direct relationship to leaf starch levels, and there was no similarity between activities in immature and mature leaves. An increase in photosynthesis during plant development was observed which could account for the increased starch synthesis at initial fruit expansion.     

Elevated CO2 Effects during Leaf Ontogeny (A New Perspective on Acclimation)

For many plants growth in elevated CO2 leads to reduced rates of photosynthesis. To examine the role that leaf ontogeny plays in the acclimation response, we monitored photosynthesis and some related parameters at short intervals throughout the ontogenetic development of tobacco (Nicotiana tabacum L.) leaves under ambient (350 [mu]L L-1)- and high (950 [mu]L L-1)-CO2 conditions. The pattern of photosynthetic rate over time was similar between the two treatments and consistent with the expected pattern for a typical dicot leaf. However, the photosynthesis pattern in high-CO2-grown tobacco was shifted temporally to an earlier maximum and subsequent senescent decline. Ribulose-1,5-biphosphate carboxylase/oxygenase activity appeared to be the main factor regulating photosynthetic rates in both treatments. Therefore, we propose a new model for interpreting the acclimation response. Lowered photosynthetic rates observed during acclimation appear to be the result of a shift in the timing of the normal photosynthetic stages of leaf ontogeny to an earlier onset of the natural decline in photosynthetic rates associated with senescence.     

Brassinosteroid Modifies Growth and Essential Oil Production in Peppermint (Mentha piperita L.)

Journal of Plant Growth Regulation - This study was carried out to determine the effect of brassinosteroid (BR) (24-epibrassinolide (24-eBL) at concentration 0.5, 1.5 and 2.5 ppm) on the...     

Heterogeneity of Mitochondrial Protein Biogenesis during Primary Leaf Development in Barley

The natural developmental gradient of light-grown primary leaves of barley (Hordeum vulgare L.) was used to analyze the biogenesis of mitochondrial proteins in relation to the age and physiological changes within the leaf. The data indicate that the protein composition of mitochondria changes markedly during leaf development. Three distinct patterns of protein development were noted: group A proteins, consisting of the E1 β-subunit of the pyruvate dehydrogenase complex, ORF156, ORF577, alternative oxidase, RPS12, cytochrome oxidase subunits II and III, malic enzyme, and the α- and β-subunits of F₁-ATPase; group B proteins, consisting of the E1 α-subunit of the pyruvate dehydrogenase complex, isocitrate dehydrogenase, HSP70A, cpn60C, and cpn60B; and group C proteins, consisting of the four subunits of the glycine decarboxylase complex (P, H, T, and L proteins), fumarase, and formate dehydrogenase. All of the proteins increased in concentration from the basal meristem to the end of the elongation zone (20.0 mm from the leaf base), whereupon group A proteins decreased, group B proteins increased to a maximum at 50 mm from the leaf base, and group C proteins increased to a maximum at the leaf tip. This study provides evidence of a marked heterogeneity of mitochondrial protein composition, reflecting a changing function as leaf cells develop photosynthetic and photorespiratory capacity.     

Studies on Antifungal Properties of Essential Oil of Trachyspermum ammi (L.) Sprague

The essential oil from the fruits of Trachyspermum ammi exhibited toxicity at 800 ppm against Aspergillus flavus and A. niger, the nature of toxicity being cidal. The toxicity of the oil was not affected by autoclaving, temperature treatment and storage upto 365 days. The oil killed the test fungi within 50 seconds; withstood heavy inoculum density and was inhibitory to as many as 21 fungi at its minimum inhibitory concentration. However the seeds of Arachis hypogea whentreated with oil at 5000 ppm and stored for 12 months did not show the appearance of any fungi indicating thereby the grain protectant activity of the oil. The oil was characterized by various physico chemical properties and on chemical investigation Thymol and p-cymene were isolated as antifungal principles of the oil exhibiting toxicity against the test fungi at 1000 ppm.