Hairy root cultures of Anethum graveolens (dill): establishment, growth, time-course study of their essential oil and its comparison with parent plant oils

Transformed root cultures of Anethum graveolens were induced by inoculation of aseptically grown seedlings with Agrobacterium rhizogenes carrying plasmid pRi 1855. The main component of the essential oils from the fruits and from the roots of the parent plant was carvone, whereas -phellandrene and apiole were dominant in the oil from, respectively, the aerial parts and the hairy roots. The essential oils from the fruits, aerial parts and roots of the parent plant were at 2%, 0.3% and 0.06% (v/w), respectively, but only 0.02% (v/w) in the hairy root cultures. Growth of the hairy root cultures reached 600 mg dry wt/50 ml medium after 50 days. The essential oil composition did not change significantly during their growth.     

Potential use of the essential oil ofTrachyspermum ammi against seed-borne fungi of Guar (Cyamopsis tetragonoloba L. (Taub.))

Essential oils isolated from leaves and seeds of seven umbelliferous plants were tested against the growth ofAspergillus flavus. Those from seeds ofTrachyspermum ammi, Cuminum cyminum, Carum carvi, Daucus carota and from leaves ofAnethum graveolens exhibited antifungal activity against the test fungus. Amongst these, oil from seeds ofTrachyspermum ammi was most toxic. Its minimum inhibitory concentration was 300 ppm, at which it exhibited fungistatic but not phytotoxic properties, when tested at 200, 300 and 400 ppm. The fungitoxic potency ofTrachyspermum seed oil remained unchanged after a long storage period and at high inoculum density of the test fungus. The oil was thermostable and was more efficaceous than the fungicides Agrosan G.N., Benlate, Ceresan, Dithane M-45 and Thiovit commonly used for the control of plant diseases.     

Antifungal activity of the dill (Anethum graveolens L.) seed essential oil against strawberry anthracnose under in vitro and in vivo conditions

Strawberry anthracnose, caused by Colletotrichum nymphaeae, is mainly controlled by the application of synthetic chemical fungicides. The present study assessed the antimicrobial activity of essential oils (EOs) from dill (Anethum graveolens L.) seed against C. nymphaeae. The antifungal effects of dill seed EO on C. nymphaeae was initially evaluated in vitro and further extended as in vivo condition. The results indicate that in the contact and volatile assays, dill seed EO significantly inhibited mycelial growth of C. nymphaeae at all concentrations tested. Conidia germination was also significantly inhibited at concentrations of 250 – 1000 ppm. Disease incidence and severity of anthracnose on strawberry fruits were significantly reduced compared with infected control, from concentrations of 500 and 50 ppm, respectively. The results confirm the efficacy of dill seed EO against C. nymphaeae, which may represent an alternative to synthetic chemical fungicides to control strawberry anthracnose pre- and post-harvest.     

Effects of liming and mycorrhizal colonization on soil phosphate depletion and phosphate uptake by maize (Zea mays L.) and soybean (Glycine max L.) grown in two tropical acid soils

The effects of liming and inoculation with the arbuscular mycorrhizal fungus, Glomus intraradices Schenck and Smith on the uptake of phosphate (P) by maize (Zea mays L.) and soybean (Glycine max [L.] Merr.) and on depletion of inorganic phosphate fractions in rhizosphere soil (Al-P, Fe-P, and Ca-P) were studied in flat plastic containers using two acid soils, an Oxisol and an Ultisol, from Indonesia. The bulk soil pH was adjusted in both soils to 4.7, 5.6, and 6.4 by liming with different amounts of CaCO₃.In both soils, liming increased shoot dry weight, total root length, and mycorrhizal colonization of roots in the two plant species. Mycorrhizal inoculation significantly increased root dry weight in some cases, but much more markedly increased shoot dry weight and P concentration in shoot and roots, and also the calculated P uptake per unit root length. In the rhizosphere soil of mycorrhizal and non-mycorrhizal plants, the depletion of Al-P, Fe-P, and Ca-P depended in some cases on the soil pH. At all pH levels, the extent of P depletion in the rhizosphere soil was greater in mycorrhizal than in non-mycorrhizal plants. Despite these quantitative differences in exploitation of soil P, mycorrhizal roots used the same inorganic P sources as non-mycorrhizal roots. These results do not suggest that mycorrhizal roots have specific properties for P solubilization. Rather, the efficient P uptake from soil solution by the roots determines the effectiveness of the use of the different soil P sources. The results indicate also that both liming and mycorrhizal colonization are important for enhancing P uptake and plant growth in tropical acid soils.     

Arbuscular mycorrhiza alter the concentration of essential oils in oregano (Origanum sp., Lamiaceae)

The effect of root colonization by Glomus mosseae on the qualitative and quantitative pattern of essential oils (EO) was determined in three oregano genotypes (Origanum sp.). To exclude a simple P-mediated effect through mycorrhization the effect of P application to plants on the EO accumulation was also tested. In two genotypes the leaf biomass was increased through mycorrhization. Root colonization by the arbuscular mycorrhizal fungus (AMF) did not have any significant effect on the EO composition in oregano; however, in two genotypes the EO concentration significantly increased. As EO levels in P-treated plants were not enhanced, we conclude that the EO increase observed in mycorrhizal oregano plants is not due to an improved P status in mycorrhizal plants, but depends directly on the AMF–oregano plant association.     

Turnover of cell-wall polysaccharides during somatic embryogenesis and development of celery (Apium graveolens L.)

Non-embryogenic cells (NEC) and embryogenc cells (EC) were separated from cell clusters derived from the hypocotyl segments of celery seedlings, which had been suspension-cultured in MS medium supplemented with 10⁵ M 2,4-D. The EC formed globular embryos in medium without 2,4-D. The globular embryo developed through heart-shaped, torpedo to cotyledonary embryos within 10 days. The EC and developing embryos were fractionated into symplastic [MeOH, hot water (HW), starch (S)] and apoplastic [pectin, hemicellulose, TFA (trifluoroacetic acid)-soluble and cellulose] fractions. The EC contained lower levels of sugar in the MeOH fraction and higher levels of starch than NEC. In the apoplastic fractions, there were no differences of total sugar amounts between NEC and EC. Cellulose contents were about 10% of the wall polysaccharides. During somatic embryogenesis, total sugar contents of the MeOH and HW fractions increased till the heart-shaped embryo stage, and then decreased during the torpedo and cotyledonary embryo stages. The sugar contents of the starch, pectin, TFA-soluble, and cellulose fractions did not change during the stages mentioned above. However, the hemicellulose substances remarkably increased during embryogenesis, and then decreased as the development proceeded. The neutral sugar components of the hemicellulosic fractions were analyzed. Arabinose increased markedly in EC to the globular embryo stage, but decreased as the development proceeded. Galactose increased only at the torpedo and cotyledonary embryo stages. Xylose was present at lower levels in all stages of embryogenesis than in the differentiated hypocotyl cell walls. These results suggest that there was a high turnover of arabinogalactan polysaccharides during embryogenesis, and that xylan accumulated in the cell walls of differentiated cells     

Fumigant toxicity of essential oil of Mugwort (Artemisia vulgaris L.) against three major stored product beetles

Application of plants essential oil for the evaluation of their fumigant toxicity and insecticidal properties is the goal of many researches. In this study, aerial parts of Artemisia vulgaris L. were subjected to hydrodistillation using a Clevenger-type apparatus, and the chemical composition of the volatile oils was studied by gas chromatography–mass spectrometry. Alpha-Pinene (23.56) was the main component of the essential oil. Insecticidal activity of the oil was evaluated against Tribolium castaneum (Herbst), Callosobruchus maculatus (F.) and Rhizopertha dominica (F.) after 24, 48 and 72 h. After 24-h exposure time, C. maculatus was more susceptible (LC₅₀ = 52.47 μl/l air) and T. castaneum was more tolerant (LC₅₀ = 279.86 μl/l air) than other species. LT₅₀ values were indicated using highest concentration of LC₅₀ tests for three species. In general, mortality increased as the doses of essential oil and exposure time increased. These results proposed that A. vulgaris oil might have potential as a control agent against T. castaneum, R. dominica and especially C. maculates in storages.     

Chemical composition and antimicrobial activity of the essential oil of Cacalia tangutica (Maxim.) Hand.-Mazz

Essential oil of the subterranean part of Cacalia tangutica (Maxim.) Hand.-Mazz was analyzed by gas chromatography (GC)-mass spectrum (MS) technique in two different capillary columns of different polarities. Thirty-one components were identified in the oil and the main compounds were α-zingiberene (13.49%), germacrene D (10.76%), α-pinene (8.54%), caryophyllene(Z-) (6.36%), linalool (6.16%), β-myrcene (4.89%), β-ocimene (Z-) (4.40%)and ocimenone(Z-) (3.58%). The antimicrobial activity of the oil was evaluated against 2 fungi and 12 bacteria including 6 clinically isolated strains using the agar disc diffusion and broth microdilution methods. The results show that the oil presented a broad antimicrobial spectrum and had better antimicrobial activity against yeast and gram-positive bacteria. The minimum inhibitory concentration values were 0.16–5.00 g/L and minimum bactericidal concentration values were 0.16–5.00 g/L. __________ Translated from Journal of Wuhan University (Science Edition), 2007, 53 (2): 198–203 [译自: 武汉大学学报(理学版)]     

Chemical analysis of the essential oil of Ferula glauca L. (Apiaceae) growing in Marche (central Italy)

Ferula glauca L. (Apiaceae), formerly believed a subspecies of Ferula communis L., but at the present considered a distinguishable species, was studied for the first time for volatiles from leaves, flowers, fruits and roots. The chemical analysis of the essential oil obtained from different populations growing in Marche (central Italy) was performed by GC-FID and GC–MS. The differences in composition detected between F. glauca and F. communis made the volatile fraction a reliable marker to distinguish between them, and confirmed the botanical data at the base of their discrimination. In particular, the oils obtained from leaves and roots, contained as major compounds (E)-caryophyllene, caryophyllene oxide, myristicin and elemicin, that can be useful as marker components. Finally, the oils contained some daucane derivatives, that were detected also in F. communis and responsible for important biological properties.     

Mycorrhiza formation and nutrient concentration in leeks (Allium porrum) in relation to previous crop and cover crop management on high P soils

An improved integration of mycorrhizas may increase the sustainability in plant production. Two strategies for increasing the soil inoculum potential of mycorrhizal fungi were investigated in field experiments with leeks: Pre-cropping with mycorrhizal main crops and pre-establishment of mycorrhizal cover crops. Experiments on soils with moderate to high P content (26–50 mg kg^–1 bicarbonate-extractable P) showed that the previous crop influenced mycorrhiza formation, uptake of P, Zn, and Cu, and early growth of leek seedlings. A cover crop of black medic, established the previous autumn, increased the colonization of leek roots by mycorrhizal fungi. During early growth stages, this increase was 45–95% relative to no cover crop. However, cover cropping did not significantly increase nutrient concentration or growth. These variables were not influenced by the time of cover crop incorporation or tillage treatments. Differences in colonization, nutrient uptake and plant growth diminished during the growing period and at the final harvest date, the effects on plant production disappeared. High soil P level or high soil inoculum level was most likely responsible for the limited response of increased mycorrhiza formation on plant growth and nutrient concentrations.     

Investigation of the essential oil from eight species of Baccharis belonging to sect. Caulopterae (Asteraceae, Astereae): a taxonomic approach

Essential oils of B. articulata, B. crispa, B. microcephala, Baccharis milleflora, B. myriocephala, B. stenocephala, B. trimera and B. usterii, all of sect. Caulopterae, have been analyzed by GC and GC/MS. Despite the morphological similarity among these species, differences in composition of their essential oil obtained by hydrodistillation and hexane extract could be observed. Special attention was given to Baccharis trimera and B. crispa since their differentiation during early stages is not possible due to the absence of synflorescences. Carquejyl acetate is suggested as a marker for Baccharis trimera, and a fast method of detection of this compound is given.     

Efficacy of Elettaria cardamomum L. (Zingiberaceae) essential oil on the two spotted spider mite,Tetranychus urticae Koch (Acari: Tetranychidae)

Two-spotted spider mite, Tetranychus urticae Koch is the major pest of various plants worldwide. Now the control is dependent on the use of chemical pesticides. Plant compounds are recently known as biopesticides. Essential oil of Elettaria cardamomum was researched on repellent and oviposition inhibition of T. urticae. The LC₅₀ values of fumigant toxicity of this oil on adults and eggs of the two spotted spider mite were 7.26 and 8.82?μL/L air, respectively. Also LT₅₀ value of essential oil at 45?μL/L air was 23.86?h and LT₅₀ value of essential oil at 60?μL/L air was 9.01?h. In addition, different concentrations of the essential oil of E. cardamomum significantly affected oviposition deterrence and repellency of adults. The results of this study indicated that essential oil of E. cardamomum may be considered as a biopesticide to control two spotted spider mites.     

Sensitivity of Asellus aquaticus (L.) and Proasellus coxalis Dollf. (Crustacea,Isopoda) to Copper

The effects of Copper on the life-cycle of two crustacean isopods, Asellus aquaticus (L.) and Proasellus coxalis Dollf., are studied. ST₅₀ indicates that females and males are differently sensitive in comparison with juveniles. The two species do not show differences in sensitivity in the range of 0.01–15 mg·1^-1 between adults and juveniles. The effect of 0.005 mg·1^-1 Copper sulphate was strongest on embryonic and larval stages. Ecological implications are discussed.     

Fumigant toxicity of essential oil from Tanacetum balsamita L. (Compositae) against adults and eggs of Callosobruchus maculatus F. (Coleoptera: Bruchidae)

The essential oil of Tanacetum balsamita L. was tested against Callosobruchus maculatus F. at the rates of 5.12, 7.23, 10.19, 14.36 and 20.24?μl/l?air for adults and 5.3, 8.5, 10.8, 13.7 and 17.4?μl/l?air for eggs. All experiments were conducted at 27?±?1?°C and 65?±?5% relative humidity. Mortality was counted after 24, 48 and 72?h of exposure and all adults (dead and alive) were taken out of the vials and the vials were left at the same conditions for further 35?days to assess progeny production. For mortality of eggs, unhatched eggs were counted after 7?days. The adults treated with oil were more susceptible than eggs. At highest dose (20.24?μl/l?air) mortality of adults after 72?h, received 75.2%, but this amount for egg at 17.4?μl/l?air after 72?h was 49.06%. The lowest LC₅₀ value on 72?h was observed in adults (1.96?μl/l?air). Also, the lowest LC₉₅ value on 72?h was observed in adults (42.86?μl/l?air). The percentage of reduced progeny on 72?h was 50.92% at 20.24?μl/l?air. Our results suggest that T. balsamita can be used as an alternative to synthetic insecticides but higher dose may be needed.     

Thermal requirements for the embryonic development of Periplaneta americana (L.) (Dictyoptera: Blattidae) with potential application in mass-rearing of egg parasitoids

The embryonic development of oothecae of Periplaneta americana was evaluated under four different constant temperatures (5, 10, 15, 20, 25, 30, and 35 °C) and also at different exposure times at <5 °C. Their suitability as hosts after the treatment for the parasitoids Evania appendigaster and Aprostocetus hagenowii was also assessed. Temperatures of 5, 10, 15, and 35 °C adversely affected the development of the cockroaches, and exposure times to <5 °C longer than 5 days sufficed to kill all the embryos in the oothecae. The lower thermal threshold for complete development of P. americana was estimated to be 6.8 °C, with a required total amount of 900.9 degree-days. Cold-killed oothecae were still fit for the development of parasitoids. Parasitism rates of A. hagenowii were higher than those of E. appendigaster, although with lower emergence rates. Our results can be useful in aiding mass-rearing of these parasitoids for biological control programmes of P. americana, and may help forecast the time of emergence of nymphs of American cockroaches in infested areas.     

Life cycles and distribution of the aquatic gastropod molluscs Bithynia tentaculata (L.), Gyraulus albus (Muller), Planorbis planorbis (L.) and Lymnaea peregra (Muller) in relation to water chemistry

The ecology of the aquatic gastropods Bithynia tentaculata, Gyraulus albus, Planorbis planorbis and Lymnaea peregra in North West England was investigated over 13 months at sites chosen for their wide range of water chemistry. Multiple regression analysis was used to determine the significance to the mollusc distributions of a variety of physico-chemical factors. Biotic factors were not considered. The species had similar life cycles, with little difference between populations within a species. B. tentaculata could live for over a year, and the major water chemistry variable was potassium (+), where the sign is that of the regression coefficient. G. albus could also survive into a second year and the major variable was mud substratum type (+). Rock substratum type (-) was the most important factor for P. planorbis. There was a slight difference in the life cycles of L. peregra in hard and medium compared with soft waters and the major water chemistry variable was magnesium (-).     

Sucrose mobilization in relation to essential oil biogenesis during palmarosa (<Emphasis Type="Italic">Cymbopogon martinii</Emphasis> Roxb. Wats. var.<Emphasis Type="Italic">motia</Emphasis>) inflorescence development

Palmarosa inflorescence with partially opened spikelets is biogenetically active to incorporate [U-¹⁴C]sucrose into essential oil. The percent distribution of¹⁴C-radioactivity incorporated into geranyl acetate was relatively higher as compared to that in geraniol, the major essential oil constituent of palmarosa. At the partially opened spikelet stage, more of the geraniol synthesized was acetylated to form geranyl acetate, suggesting that majority of the newly synthesized geraniol undergoes acetylation, thus producing more geranyl acetate.In vitro development of palmarosa inflorescence, fed with [U-¹⁴C]sucrose, resulted in a substantial reduction in percent label from geranyl acetate with a corresponding increase in free geraniol, thereby suggesting the role of an esterase in the production of geraniol from geranyl acetate. At time course measurement of¹⁴CO₂ incorporation into geraniol and geranyl acetate substantiated this observation. Soluble acid invertase was the major enzyme involved in the sucrose breakdown throughout the inflorescence development. The activities of cell wall bound acid invertase, alkaline invertase and sucrose synthase were relatively lower as compared to the soluble acid invertase. Sucrose to reducing sugars ratio decreased till fully opened spikelets stage, concomitant with increased acid invertase activity and higher metabolic activity. The phenomenon of essential oil biosynthesis has been discussed in relation to changes in these physiological parameters.