Preparation and Phytotoxicity Evaluation of 11,13-Dehydro seco-Guaianolides.

11,13-Dehydro seco-guaianolides, a particular type of sesquiterpene lactones, were synthesized from the commercially available α-santonin (11) using a facile strategy involving a high-yielding photochemical reaction. Natural products 10 and 17 from Artemisia gorgonum were synthesized in good yields. Specifically, compound 10 was obtained in five steps with an overall yield of 17%. The sesquiterpene lactones were tested in the etiolated wheat coleoptile bioassay, and the most active compounds were assayed on standard target species. Guaianolide 13 showed the highest phytotoxic activities when compared with the known herbicide Logran.

Variation in tissue Na(+) content and the activity of SOS1 genes among two species and two related genera of Chrysanthemum.

BACKGROUND: Chrysanthemum, a leading ornamental species, does not tolerate salinity stress, although some of its related species do. The current level of understanding regarding the mechanisms underlying salinity tolerance in this botanical group is still limited. RESULTS: A comparison of the physiological responses to salinity stress was made between Chrysanthemum morifolium 'Jinba' and its more tolerant relatives Crossostephium chinense, Artemisia japonica and Chrysanthemum crassum. The stress induced a higher accumulation of Na(+) and more reduction of K(+) in C. morifolium than in C. chinense, C. crassum and A. japonica, which also showed higher K(+)/Na(+) ratio. Homologs of an Na(+)/H(+) antiporter (SOS1) were isolated from each species. The gene carried by the tolerant plants were more strongly induced by salt stress than those carried by the non-tolerant ones. When expressed heterologously, they also conferred a greater degree of tolerance to a yeast mutant lacking Na(+)-pumping ATPase and plasma membrane Na(+)/H(+) antiporter activity. The data suggested that the products of AjSOS1, CrcSOS1 and CcSOS1 functioned more effectively as Na (+) excluders than those of CmSOS1. Over expression of four SOS1s improves the salinity tolerance of transgenic plants and the overexpressing plants of SOS1s from salt tolerant plants were more tolerant than that from salt sensitive plants. In addition, the importance of certain AjSOS1 residues for effective ion transport activity and salinity tolerance was established by site-directed mutagenesis and heterologous expression in yeast. CONCLUSIONS: AjSOS1, CrcSOS1 and CcSOS1 have potential as transgenes for enhancing salinity tolerance. Some of the mutations identified here may offer opportunities to better understand the mechanistic basis of salinity tolerance in the chrysanthemum complex.

Salicylic acid-induced changes in physiological parameters and genes of the flavonoid biosynthesis pathway in Artemisia vulgaris and Dendranthema nankingense during aphid feeding.

Phloem-feeding aphids cause serious damage to plants. The mechanisms of plant-aphid interactions are only partially understood and involve multiple pathways, including phytohormones. In order to investigate whether salicylic acid (SA) is involved and how it plays a part in the defense response to the aphid Macrosiphoniella sanbourni, physiological changes and gene expression profiles in response to aphid inoculation with or without SA pretreatment were compared between the aphid-resistant Artemisia vulgaris 'Variegata' and the susceptible chrysanthemum, Dendranthema nankingense. Changes in levels of reactive oxygen species, malondialdehyde (MDA), and flavonoids, and in the expression of genes involved in flavonoid biosynthesis, including PAL (phenylalanine ammonia-lyase), CHS (chalcone synthase), CHI (chalcone isomerase), F3H (flavanone 3-hydroxylase), F3'H (flavanone 3'-hydroxylase), and DFR (dihydroflavonol reductase), were investigated. Levels of hydrogen peroxide, superoxide anions, MDA, and flavonoids, and their related gene expression, increased after aphid infestation and SA pretreatment followed by aphid infestation; the aphid-resistant A. vulgaris exhibited a more rapid response than the aphid-susceptible D. nankingense to SA treatment and aphid infestation. Taken together, our results suggest that SA could be used to increase aphid resistance in the chrysanthemum.

Horseradish peroxidase-assisted approach to decolorize and detoxify dye pollutants in a packed bed bioreactor.

In this study, horseradish peroxidase (HRP) was covalently immobilized on the calcium-alginate support using glutaraldehyde (GA) as a cross-linking reagent for detoxification and degradation of synthetic dyes. Immobilization procedure furnished significant immobilization efficiency (86.27 ± 3.43%) along with apparent and relative activity of 24.39 ± 1.03 U/g and 84.97 ± 3.54%, respectively, for immobilized-HRP. In comparison to free-state, immobilized-HRP catalyzed the substrate oxidation reaction in a slightly acidic and wider temperature range, with an optimum at 60 °C. After 10 and 60 min of incubation at 60 °C, the immobilized-HRP displayed 99.0% and 89.0% of residual activities, whereas the free counterpart retained only 34.0% and 18.0% of residual activities, respectively. Moreover, the immobilized-HRP showed potential efficiency for the decolorization of dyes in sequential dye-decolorizing batch reactions. Cytotoxicity analysis using a plant bioassay and acute test demonstrated that the Ca-alginate immobilized-HRP may effectively be used for detoxification of dyes and has a great potential for large-scale environmental remediation.

Nitrogen addition pulse has minimal effect in big sagebrush (Artemisia tridentata) communities on the Pinedale Anticline, Wyoming (USA).

Nitrogen additions are known to elicit variable responses in semi-arid ecosystems, with responses increasing with precipitation. The response of semi-arid ecosystems to nitrogen are important to understand due to their large spatial extent worldwide and the global trend of increasingly available nitrogen. In this study, we evaluated the impact of a single nitrogen addition pulse on a semi-arid big sagebrush (Artemisia tridentata) ecosystem in western Wyoming. This is important given that sagebrush ecosystems are poorly understood, despite their prevalence in the western US. In addition, large-scale nitrogen additions have begun on sagebrush landscapes in Wyoming in order to mitigate population declines in mule deer (Odocoileus hemionus). The study objectives were (1) to evaluate the effectiveness of a nitrogen fertilization pulse in increasing sagebrush biomass and forage quality, and (2) to assess effects of nitrogen addition on soil biogeochemistry and vegetation community structure. We fertilized 15 plots across 5 locations in western Wyoming using a single pulse of urea (5.5g N m-2). In addition, we immobilized available nitrogen through surface hay treatments (250g hay/m2). Nitrogen additions failed to increase growth of sagebrush, alter nitrogen content of sagebrush leaders, or alter greenhouse gas efflux from soils. The plant community also remained unchanged; total cover, species richness, and community composition were all unaffected by our treatment application. Over the two years of this study, we did not find indications of nitrogen limitation of ecosystem processes, despite a wet growing season in 2014. Thus, we have found a general lack of response to nitrogen in sagebrush ecosystems and no treatment effect of a single pulse of N to sagebrush biomass or forage quality.

Tradeoff between resistance induced by volatile communication and over-topping vertical growth.

Plants commonly respond to reliable cues about herbivores by inducing greater defenses. Defenses are assumed to incur costs for plants when they are not needed. Sagebrush responds to volatile cues from experimentally clipped neighbors to induce resistance against chewing herbivores. Rather than experiencing costs, sagebrush seedlings that responded to dishonest cues were previously found to have increased survival and established plants that responded produced more inflorescences and new lateral branches. Here I report that young sagebrush plants that responded to cues added less vertical growth than controls that were not presented with volatile cues. This tradeoff between induced resistance and vertical, overtopping growth may allow agronomists to increase defense without sacrificing desirable traits. Overtopping growth is often beneficial for wild plants but often detrimental in agriculture.

Multiple mechanisms of heavy metal tolerance are differentially expressed in ecotypes of Artemisia fragrans.

Artemisia fragrans is a plant species with ability of growing on heavy metal-polluted soils. Ecotypes of this species naturally growing in polluted areas can accumulate and tolerate different amounts of heavy metals (HM), depending on soil contamination level at their origin. Heavy metal tolerance of various ecotypes collected from contaminated (AP, SP) and non-contaminated (BG) sites was compared by cultivation on a highly HM-contaminated river sediment and a non-contaminated agricultural control soil. Tissue-specific HM distribution was analyzed by laser ablation-inductively-coupled plasma-mass spectroscopy (LA-ICP-MS) and photosynthetic activity by non-invasive monitoring of chlorophyll fluorescence. Plant-mineral analysis did not reveal ecotype-differences in concentrations of Cd, Zn, Cu in shoots of Artemisia plants, suggesting no differential expression of root uptake or root to shoot translocation of HM. There was also no detectable rhizosphere effect on HM concentrations on the contaminated soil. However, despite high soil contaminations, all ecotypes accumulated Zn only in the concentration range of generally reported for normal growth of plants, while Cu and Cd concentrations were close to or even higher than the toxicity level for most plants. As a visible symptom of differences in HM tolerance, only the AP ecotype was able to enter the generative phase to complete its life cycle. Analysis of tissue-specific metal distribution revealed significantly lower concentrations of Cd in the leaf mesophyll of this ecotype, accumulating Cd mainly in the leaf petioles. A similar mesophyll exclusion was detectable also for Cu, although not associated with preferential accumulation in the leaf petioles. However, high mesophyll concentrations of Cd and Cu in the SP and BG ecotypes were associated with disturbances of the photosynthetic activity. The findings demonstrate differential expression of HM exclusion strategies in Artemisia ecotypes and suggest Cd and Cu exclusion from the photosynthetically active tissues as a major tolerance mechanism of the AP ecotype.

The phytotoxic effect of C(1)/C(2)-halocarbons and trichloroacetic acid on the steppe plant Artemisia lerchiana.

Artemisia lerchiana is a wormwood species of the Central Asian steppe regions, where it completely cover whole areas. For the first time it was possible to show through field experiments that C(1)/C(2) halocarbons (VCHCs), such as chloroform (CHL), tetrachloroethene (PER) and hexachloroethane (HEX), can be taken up by test plants of the species A. lerchiana via the soil/root pathway and metabolised inter alia into trichloroacetic acid (TCA) under semi-aride conditions. At the same time, chlorophyll a fluorescence measurements carried out on the test plants revealed a phytotoxic influence on plant vitality (max. decline in vitality of 52% with application of CHL) and less efficient energy flows in the photosynthesis mechanism of the A. lerchiana test plants. The authors examine possible links between the simultaneous appearance of VCHCs and additional drought stress in the acceleration of desertification processes.

Genome-Scale Transcriptome Analysis of the Desert Shrub Artemisia sphaerocephala.

BACKGROUND: Artemisia sphaerocephala, a semi-shrub belonging to the Artemisia genus of the Compositae family, is an important pioneer plant that inhabits moving and semi-stable sand dunes in the deserts and steppes of northwest and north-central China. It is very resilient in extreme environments. Additionally, its seeds have excellent nutritional value, and the abundant lipids and polysaccharides in the seeds make this plant a potential valuable source of bio-energy. However, partly due to the scarcity of genetic information, the genetic mechanisms controlling the traits and environmental adaptation capacity of A. sphaerocephala are unknown. RESULTS: Here, we present the first in-depth transcriptomic analysis of A. sphaerocephala. To maximize the representation of conditional transcripts, mRNA was obtained from 17 samples, including living tissues of desert-growing A. sphaerocephala, seeds germinated in the laboratory, and calli subjected to no stress (control) and high and low temperature, high and low osmotic, and salt stresses. De novo transcriptome assembly performed using an Illumina HiSeq 2500 platform resulted in the generation of 68,373 unigenes. We analyzed the key genes involved in the unsaturated fatty acid synthesis pathway and identified 26 A. sphaerocephala fad2 genes, which is the largest fad2 gene family reported to date. Furthermore, a set of genes responsible for resistance to extreme temperatures, salt, drought and a combination of stresses was identified. CONCLUSION: The present work provides abundant genomic information for functional dissection of the important traits of A. sphaerocephala and contributes to the current understanding of molecular adaptive mechanisms of A. sphaerocephala in the desert environment. Identification of the key genes in the unsaturated fatty acid synthesis pathway could increase understanding of the biological regulatory mechanisms of fatty acid composition traits in plants and facilitate genetic manipulation of the fatty acid composition of oil crops.

Evaluation of chemopreventive and chemotherapeutic effect of Artemisia vulgaris extract against diethylnitrosamine induced hepatocellular carcinogenesis in Balb C mice / Avaliação dos efeitos quimiopreventivo e quimioterápico do extrato de Artemisia vulgaris contra carcinogênese hepatocelular induzida por dietilnitrosamina em camundongos Balb C

The main objective of current study was to investigate the chemopreventive and chemotherapeutic activity of Artemisia vulgaris extract on diethylnitrosoamine induced hepatocarcinogenesis in Balb C mice. Diethylnitrosoamine (DEN: 0.9%) was prepared to induce hepatocarcinoma in Balb C mice. The extract Artemisia vulgaris (AV) was prepared by maceration technique. Mice were classified into four groups as follows: Group 1 a control group (N=7) received saline solution (3.5 l/mg), group 2 (N=14) received diethylnitrosoamine (3.5 l/mg) intraperitoneally once in a week for eight consecutive weeks, group 3 (N=7) received only plant extract (AV: 150 mg/kg (Body weight) once in a week, while group 4 (N=7) was given in combination of diethylnitrosoamine (3.5 l/mg) and plant extract (AV: 150 mg/kg (body weight). After eight weeks of DEN administration, mice of group 2 were divided into two subgroups containing seven mice each; subgroup 1 was sacrificed while subgroup 2 was treated with plant extract only (150 mg/kg (body weight)) once in a week for eight consecutive weeks. The DEN injected mice significant decline in levels of albumin with concomitant significant elevations such as aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, alpha feto protein, gamma glutamyl transferase, 5 nucleotidase, glucose-6-phosphate dehydrogenase and bilirubin. The administration of A. vulgaris significantly decreased the DEN induced hepatotoxicity. Present study revealed the potential anti-cancerous nature of Artemisia vulgaris, both in case of chemopreventive and post-treatment of A. vulgaris. Further studies are needed to explore the mechanism of prevention and therapy.

O objetivo principal do presente estudo foi investigar as atividades quimiopreventiva e quimioterápica do extrato de Artemisia vulgaris em hepatocarcinogênese induzida por dietilnitrosoamina (DEN) em camundongos Balb C. Dietilnitrosoamina (DEN: 0,9%) foi preparada para induzir hepatocarcinoma em camundongos da linhagem Balb C. O extrato de A. vulgaris (AV) foi preparado pela técnica de maceração. Os camundongos foram classificados em quatro grupos conforme os seguintes: grupo 1, grupo controle (N=7) recebeu solução salina (3,5 µl/mg); grupo 2 (N=14) recebeu dietilnitrosoamina (3,5 µl/mg) por via intraperitoneal uma vez por semana durante oito semanas consecutivas; grupo 3 (N=7) recebeu apenas o extrato vegetal (AV: 150 mg/kg (peso corporal) uma vez por semana; enquanto no grupo 4 (N=7) foi administrado uma combinação de dietilnitrosoamina (3,5 l/mg) com extrato vegetal (AV: 150 mg/kg (peso corporal). Após oito semanas de administração de DEN, os camundongos do grupo 2 foram divididos em dois subgrupos, contendo sete camundongos cada um; no subgrupo 1, os animais foram sacrificados, enquanto no subgrupo 2, os animais foram tratados apenas com extrato vegetal (150 mg/kg (peso corporal)) uma vez por semana durante oito semanas consecutivas. Os camundongos nos quais foram injetados DEN apresentaram declínio significativo nos níveis de albumina, mas elevações significativas concomitantes de: aspartato aminotransferase, alanina aminotransferase, lactato desidrogenase, alfa-fetoproteína, gama-glutamiltransferase, 5 nucleotidase, glicose-6-fosfato desidrogenase e bilirrubina. A administração de A. vulgaris diminuiu significativamente a hepatotoxicidade induzida pelo DEN. O presente estudo apresentou a potencialidade anticancerosa da A. vulgaris, tanto nos casos de quimioprevenção quanto no pós-tratamento da A. vulgaris. Mais estudos são necessários para explorar o mecanismo de prevenção e a terapia.

Galanthamine, an anticholinesterase drug, effects plant growth and development in Artemisia tridentate Nutt. via modulation of auxin and neutrotransmitter signaling.

Galanthamine is a naturally occurring acetylcholinesterase (AchE) inhibitor that has been well established as a drug for treatment of mild to moderate Alzheimer disease, but the role of the compound in plant metabolism is not known. The current study was designed to investigate whether galanthamine could redirect morphogenesis of Artemisia tridentata Nutt. cultures by altering concentration of endogenous neurosignaling molecules acetylcholine (Ach), auxin (IAA), melatonin (Mel), and serotonin (5HT). Exposure of axenic A. tridentata cultures to 10 µM galanthamine decreased the concentration of endogenous Ach, IAA, MEL, and AchE, and altered plant growth in a manner reminiscent of 2-4D toxicity. Galanthamine itself demonstrated IAA activity in an oat coleotile elongation bioassay, 20 µM galanthamine showed no significant difference compared with 5 µM IAA or 5 µM 1-Naphthaleneacetic acid (NAA). Metabolomic analysis detected between 20,921 to 27,891 compounds in A. tridentata plantlets and showed greater commonality between control and 5 µM treatments. Furthermore, metabolomic analysis putatively identified coumarins scopoletin/isoscopoletin, and scopolin in A. tridentata leaf extracts and these metabolites linearly increased in response to galanthamine treatments. Overall, these data indicate that galanthamine is an allelopathic phytochemical and support the hypothesis that neurologically active compounds in plants help ensure plant survival and adaptation to environmental challenges.

Cytokinin and auxin effect on the terpenoid profile of the essential oil and morphological characteristics of shoot cultures of Artemisia alba.

The influence of plant growth regulators (PGR) on the essential oil composition and in vitro development of A. alba shoot cultures was studied. Two types of oils were determined, based on their terpenoid content. Close relations between the morphogenetic effects of PGR and the essential oil profile of the species were observed Predominance of root over shoot development was connected with a drop in the amounts of sesquiterpenoids and the direction of biosynthesis towards oxygenated monoterpenoids in the PGR-free control medium, as well in those with 1.0 mg L(-1) indole-3-butyric acid (IBA) supplementation. On the contrary, lack of root formation and stimulated callusogenesis caused by the addition of 0.2 mg L(-1) 6-benzyladenine (BA), irrespectively of the presence of IBA (either 0.5 mg L(-1) or 1.0 mg L(-1)), resulted in the strong prevalence of sesquiterpenoids in the oils. These results are indicative that the morphological development ofA. alba shoot cultures affects the terpenoid biosynthetic pathway bringing out the hypothesis for a possible root to shoot signaling.

Mycotoxins produced by Fusarium spp. associated with Fusarium head blight of wheat in Western Australia.

An isolated occurrence of Fusarium head blight (FHB) of wheat was detected in the south-west region of Western Australia during the 2003 harvest season. The molecular identity of 23 isolates of Fusarium spp. collected from this region during the FHB outbreak confirmed the associated pathogens to be F. graminearum, F. acuminatum or F. tricinctum. Moreover, the toxicity of their crude extracts from Czapek-Dox liquid broth and millet seed cultures to brine shrimp (Artemia franciscana) was associated with high mortality levels. The main mycotoxins detected were type B trichothecenes (deoxynivalenol and 3-acetyldeoxynivalenol), enniatins, chlamydosporol and zearalenone. This study is the first report on the mycotoxin profiles of Fusarium spp. associated with FHB of wheat in Western Australia. This study highlights the need for monitoring not just for the presence of the specific Fusarium spp. present in any affected grain but also for their potential mycotoxin and other toxic secondary metabolites.

Antifungal activity, SAR and physicochemical correlation of some thiazole-1,3,5-triazine derivatives.

OBJECTIVE: Present research communication was towards the investigation of antifungal minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) activity of some substituted clubbed thiazole-1,3,5-triazines derivatives and effect of physicochemical properties on bioactivity. MATERIAL AND METHODS: MIC and MFC were evaluated against Candida albicans, Candida glabrata, Cryptococcus neoformans and Aspergillus niger using modified microdilution method recommended by CLSI. Cytotoxicity was determinate on the viability of marine shrimp larvaes. SAR and physicochemical correlations were studied by Molinspiration software. RESULTS: The 5 and 9 derivatives showed an excellent antifungal activity with MIC lower than fluconazole and equivalent to amphotericin B specially against C. albicans and C. glabrata. The toxicity of these two derivatives was non-existent for 5 and moderate for 9 at the used concentration. SAR study around prototype molecule suggests that presence of di-hydrophobic fragment on 1,3,5-triazine is necessary for antifungal activity than halogen substituted aromatic amine. CONCLUSION: On the basis of selectivity, potency and non-toxicity, we have obtained two molecules (5 and 9) as prospective leads for further research work on 1,3,5-triazine as antifungal drug.

[Effects of understory removal and nitrogen addition on the soil chemical and biological properties of Pinus sylvestris var. mongolica plantation in Keerqin Sandy Land].

A full factorial experiment was conducted to study the effects of understory removal and nitrogen addition (8 g x m(-2)) on the soil NO(3-)-N and NH(4+)-N concentrations, potential net nitrogen mineralization rate (PNM) and nitrification rate (PNN), microbial biomass C (MBC) and N (MBN), MBC/MBN, urease and acid phosphomonoesterase activities, and Olsen-P concentration in a Pinus sylvestris var. mongolica plantation in Keerqin Sandy Land during a growth season. Understory removal decreased the soil NH(4+)-N concentration, PNM, MBC, and MBN/MBN significantly, increased the soil Olsen-P concentration, but had little effects on the soil NO(3-)-N concentration, PNN, and urease and acid phosphomonoesterase activities. Nitrogen addition increased the soil NO(3-)-N concentration, PNM and PNN significantly, but had little effects on the other test properties. The interaction between understory removal and nitrogen addition had significant effects on the soil NH(4+)-N concentration, but little effects on the soil NO(3-)-N concentration. However, the soil NO(3-)-N concentration in the plots of understory removal with nitrogen addition was increased by 27%, compared with the plots of nitrogen addition alone, which might lead to the leaching of NO3-. It was suggested that understory vegetation could play an important role in affecting the soil chemical and biological properties in Mongolian pine plantations, and hence, the importance of understory vegetation should not be neglected when the forest management and restoration were implemented.

The achene mucilage hydrated in desert dew assists seed cells in maintaining DNA integrity: adaptive strategy of desert plant Artemisia sphaerocephala.

Despite proposed ecological importance of mucilage in seed dispersal, germination and seedling establishment, little is known about the role of mucilage in seed pre-germination processes. Here we investigated the role of mucilage in assisting achene cells to repair DNA damage during dew deposition in the desert. Artemisia sphaerocephala achenes were first treated γ-irradiation to induce DNA damage, and then they were repaired in situ in the desert dew. Dew deposition duration can be as long as 421 min in early mornings. Intact achenes absorbed more water than demucilaged achenes during dew deposition and also carried water for longer time following sunrise. After 4-d dew treatment, DNA damage of irradiated intact and demucilaged achenes was reduced to 24.38% and 46.84%, respectively. The irradiated intact achenes exhibited much higher DNA repair ratio than irradiated demucilaged achenes. Irradiated intact achenes showed an improved germination and decreased nonviable achenes after dew treatment, and significant differences in viability between the two types of achenes were detected after 1020 min of dew treatment. Achene mucilage presumably plays an ecologically important role in the life cycle of A. sphaerocephala by aiding DNA repair of achene cells in genomic-stressful habitats.

[Coercion and damage of Cu pollution on Artemisia lavandulaefolia growth].

By the method of solution culture, this paper studied the coercion and damage of Cu pollution on the growth of Artemisia lavandulaefolia. The Cu concentration was set as 2.5, 5, 10, 20 and 40 mg x L(-1), experimental duration was 14 days, and the growth and physiological indices of plants were tested. The results showed that the growth of A. lavandulaefolia was stimulated at low Cu concentration (2.5 mg x L(-1)), while inhibited at higher Cu concentrations (5 to approximately 40 mg x L(-1)). There was a significant negative correlation between each growth index and Cu concentration, and pigments contents had the similar trend. The sensibility of various photosynthetic pigments to Cu was in the order of chlorophyll a > chlorophyll a + b > chlorophyll b > carotenoid. Cell membrane permeability, O2 generation rate, and MDA content decreased slightly at 2.5 mg Cu x L(- 1) and then increased with increasing Cu concentration. The activities of POD, SOD and CAT increased first but decreased then with the increasing Cu concentration, and the endurance index of root showed the same trend, being > 0.5 at the Cu concentration less than 20 mg x L(-1) while decreased to 0.36 at 40 mg Cu x L(-1).

Plant-plant signaling: application of trans- or cis-methyl jasmonate equivalent to sagebrush releases does not elicit direct defenses in native tobacco.

Nicotiana attenuata plants growing in close proximity to damaged sagebrush (Artemisia tridentata ssp. tridentata) suffer less herbivory than plants near undamaged sagebrush. Sagebrush constitutively releases methyl jasmonate (MeJA), a compound that when applied directly to N. attenuata, elicits herbivore resistance and the direct defense traits [protease inhibitors (PIs), nicotine]. Damage increases the release of volatile MeJA, primarily in the cis epimer, suggesting that cis-MeJA may mediate this apparent interplant signaling. We characterized sagebrush's MeJA plume before and after damage in nature and in the laboratory, and compared the activity of trans- and cis-MeJA in inducing PIs, nicotine, and Manduca sexta resistance in N. attenuata. We used both lanolin applications and aqueous sprays that mimic natural exposures, and we determined the amount of volatilized MeJA required to elicit a nicotine response in open-grown plants. Wounding rapidly and transiently increased cis-MeJA emissions from damaged parts (but not systemically), and the released plume did not rapidly dissipate in nature. cis-MeJA was not consistently more active than trans-MeJA, and the order of exposure (trans- then cis-) did not influence activity. We conclude that volatile MeJA, either trans- or cis-, when applied at levels consistent with those released by sagebrush does not elicit direct defenses in N. attenuata.

Regeneration of the Egyptian medicinal plant Artemisia judaica L.

An in vitro propagation system for Artemisia judaica L., a traditional Egyptian medicinal plant, has been developed. De novo shoot organogenesis was induced by culturing etiolated hypocotyls and intact seedlings on medium supplemented with thidiazuron [N-phenyl-N'-(1,2,3-thidiazol-yl) urea] via callusing at the cotyledonary notch region. Up to 16 shoots formed per seedling cultured on a medium containing 1 micro mol l(-1) thidiazuron for an optimal duration of exposure of 20 days. Regenerated shoots formed roots when subcultured onto a medium containing 1 micromol l(-1) indole-3-butyric acid. The regeneration protocol developed in this study provides a basis for germplasm conservation and for further investigation of medicinally active constituents of A. judaica.