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101.
During the period 1989–1998 investigations were carried out on the parasitoids of some forest insect pests in Bulgaria. Twenty-one
ichneumonid species are reported for the first time in Bulgaria as parasitoids of different coleopteran, lepidopteran, and
hymenopteran hosts. From these, 6 parasitoids are new records for the parasitoid complexes of the hosts:Exochus decoratus Holmgr. onEudemis profundana (Den. & Schiff.) andGelechia turpella (Den. & Schiff.);Lissonota culiciformis Grav.—onParanthrene tabaniformis (Rott.);Lissonota unicincta Holmgr.—onG. turpella; Xorides gracilicornis (Grav.)—onXylotrechus sp.; andEriborus terebrator Aubert—onClostera anastomosis (L.). Most parasitoids developed as primary parasitoids in the hosts.Itoplectis alternans (Grav.) is a primary parasitoid ofNycteola asiatica (Krul.) and a hyperparasitoid ofE. terebrator: Acropimpla pictipes (Grav.) is secondary parasitoid onAnacampsis populella (Cl.). With the exception of two species ofOlesicampes genus, which destroyed over 50% ofStauronematus compressicornis (F.) andPristophora conjugata (Dahlm.) larvae, andE. terebrator which killed 15.4% ofC. anastomosis population, the rest of the parasitoids occurred in low densities, and did not play an important role in reducing the number
of their hosts. 相似文献
102.
Ibrom A Oltchev A June T Kreilein H Rakkibu G Ross T Panferov O Gravenhorst G 《Tree physiology》2008,28(4):499-508
Photosynthetically active radiation (Q)-use efficiency (epsilon) is an important parameter for deriving carbon fluxes between forest canopies and the atmosphere from meteorological ground and remote sensing data. A common approach is to assume gross primary production (P(g)) and net primary production (P(n)) are proportional to Q absorbed by vegetation (Q(abs)) by defining the proportionality constants epsilon(Pg) and epsilon(Pn) (for P(g) and P(n), respectively). Although remote sensing and climate monitoring provide Q(abs) and other meteorological data at the global scale, information on epsilon is particularly scarce in remote tropical areas. We used a 16-month continuous CO(2) flux and meteorological dataset from a mountainous tropical rain forest in central Sulawesi, Indonesia to derive values of epsilon(Pg) and to investigate the relationship between P(g) and Q(abs). Absorption was estimated with a 1D SVAT model from measured canopy structure and short wave radiation. The half-hourly P(g) data showed a saturation response to Q(abs). The amount of Q(abs) required to saturate P(g) was reduced when water vapor saturation deficit (D) was high. Light saturation of P(g) was still evident when shifting from half-hourly to daily and monthly time scales. Thus, for a majority of observations, P(g) was insensitive to changes in Q(abs). A large proportion of the observed seasonal variability in P(g) could not be attributed to changes in Q(abs) or D. Values of epsilon(Pg) varied little around the long-term mean of 0.0179 mol CO(2) (mol photon)(-1) or 0.99 g C MJ(-1) (the standard deviations were +/- 0.006 and +/- 0.0018 mol CO(2) (mol photon)(-1) for daily and monthly means, respectively). In both cases, epsilon(Pg) values were more sensitive to Q(abs) than to daytime D. These findings show that the current epsilon-approaches fail to predict P(g) at our tropical rain forest site for two reasons: (1) they neglect saturation of P(g) when Q(abs) is high; and (2) they do not include factors, other than Q(abs) and D, that determine seasonality and annual sums of P(g). 相似文献
103.
The influence of temperature (T) and water potential (ψ) on the denitrification potential, C and N mineralization and nitrification were studied in organic and mineral horizons of an acid spruce forest soil. The amount of N2O emitted from organic soil was 10 times larger than from the mineral one. The maximum of N2O emission was in both soils at the highest water potential 0 MPa and at 20°C. CO2 production in the organic soil was 2 times higher than in mineral soil. Net ammonification in organic soil was negative for most of the T‒ψ variations, while in mineral soil it was positive. Net nitrification in organic soil was negative only at the maximum water potential and temperature (0 MPa, 28°C). The highest rate was between 0 and −0.3 MPa and between 20 and 28°C. In mineral soil NO3− accumulated at all T‒ψ variations with a maximum at 20oC and −0.3 MPa. We concluded that in organic soil the immobilization of NH4+ is the dominant process in the N‒cycling. Nevertheless, decreasing of total N mineralized at 0 MPa and 20—28oC can be explained by denitrification. 相似文献
104.
Ludmila Limantseva Nina Mironenko Oleg Shuvalov Olga Antonova Alexandr Khiutti Lubov Novikova Olga Afanasenko David Spooner Tatjana Gavrilenko 《Plant Breeding》2014,133(5):660-665
Potato cyst nematodes (PCN) collected in six localities in the Leningrad region of North West Russia were identified as Globodera rostochiensis pathotype Ro1 and were used for subsequent resistance tests. Seventy‐nine accessions of cultivated and closely related wild potato species from the VIR collection in Russia were screened on resistance to G. rostochiensis pathotype Ro1 and on the presence of molecular markers for H1 and Gro1‐4 resistance genes. No associations were detected between the resistance level of diploid and tetraploid Andean and tetraploid Chilean potato landraces (indigenous cultivars) and their related wild species and their geographical distribution or presence of PCR‐based markers that are associated with the H1 and Gro1‐4 genes. At the same time, all susceptible genotypes lacked such markers. New sources of resistance were found and could be used in breeding. 相似文献
105.
106.
Vasil Georgiev Georgiev Jost Weber Eva-Maria Kneschke Petko Nedyalkov Denev Thomas Bley Atanas Ivanov Pavlov 《Plant foods for human nutrition (Dordrecht, Netherlands)》2010,65(2):105-111
Betalains are water-soluble plant pigments that are widely used as food colorants, and have a wide range of desirable biological
activities, including antioxidant, anti-inflammatory, hepatoprotective, anti-cancer properties. They can be produced from
various plants, notably beetroot, but betalain products obtained in this way also have some undesirable properties and are
difficult to standardize. A potentially attractive alternative is to use hairy root cultures. In the study reported here,
we found that betalain extracts obtained from hairy root cultures of the red beetroot B. vulgaris cv. Detroit Dark Red also had higher antioxidant activity than extracts obtained from mature beetroots: six-fold higher 2,2-dyphenyl-1-picrylhydrazyl
radical scavenging ability (90.7% inhibition, EC50 = 0.11 mg, vs 14.2% inhibition, EC50 = 0.70 mg) and 3.28-fold higher oxygen radical absorbance capacity (4,100 μM TE/g dry extract, vs 1,250 μM TE/g dry extract).
The high antioxidant activity of the hairy root extracts was associated with increased concentrations (more than 20-fold)
of total phenolic concomitant compounds, which may have synergistic effects with betalains. The presence of 4-hydroxybenzoic
acid, caffeic acid, catechin hydrate, and epicatechin were detected in both types of extract, but at different concentrations.
Rutin was only present at high concentration (1.096 mg.g−1 dry extract) in betalain extracts from the hairy root cultures, whereas chlorogenic acid was only detected at measurable
concentrations in extracts from intact plants. 相似文献
107.
Purpose
The fractionation of soil humic acids (HAs) according to their hydrophobicity is a common procedure in the study of this polydispersed complex natural mixture, so that reversed-phase high-performance liquid chromatography (RP-HPLC) is used resulting in humic components of differing hydrophobic/hydrophilic properties. However, a comparative study of the hydrophobicity of fractions isolated from different soil HAs have not been addressed so far.Materials and methods
The RP-HPLC with online absorbance detection was used for analysis of International Humic Substances Society soil standard HAs, chernozem soil HAs, and their electrophoretic fractions A, B, and C?+?D, obtained by tandem size exclusion chromatography–polyacrylamide gel electrophoresis. The strong relationship between hydrophobicity, electrophoretic mobility (EM), molecular size (MS), specific absorbance at 280 nm and aromaticity of HAs fractions was found.Results and discussion
Independently of soil HAs genesis fraction A with lowest EM and highest MS is essentially more hydrophobic (60–73 % of the fraction amount remained adsorbed on the RP column) than medium EM and MS fraction B (33–47 % of the fraction amount remained adsorbed on the RP column). The lowest hydrophobicity belongs to fraction C?+?D with highest EM and lowest MS.Conclusions
The most hydrophilic aromatic fraction C?+?D seems to have been bound with other mostly aliphatic hydrophobic fractions A and B through non covalent (possibly hydrogen) bonds. These data could be relevant to better understanding the overall makeup of soil HAs and their structural organization. 相似文献108.
During the period 1989–1998 investigations were carried out on the parasitoids of some forest insect pests in Bulgaria. Twenty-one
ichneumonid species are reported for the first time in Bulgaria as parasitoids of different coleopteran, lepidopteran, and
hymenopteran hosts. From these, 6 parasitoids are new records for the parasitoid complexes of the hosts:Exochus decoratus Holmgr. onEudemis profundana (Den. & Schiff.) andGelechia turpella (Den. & Schiff.);Lissonota culiciformis Grav.—onParanthrene tabaniformis (Rott.);Lissonota unicincta Holmgr.—onG. turpella; Xorides gracilicornis (Grav.)—onXylotrechus sp.; andEriborus terebrator Aubert—onClostera anastomosis (L.). Most parasitoids developed as primary parasitoids in the hosts.Itoplectis alternans (Grav.) is a primary parasitoid ofNycteola asiatica (Krul.) and a hyperparasitoid ofE. terebrator: Acropimpla pictipes (Grav.) is secondary parasitoid onAnacampsis populella (Cl.). With the exception of two species ofOlesicampes genus, which destroyed over 50% ofStauronematus compressicornis (F.) andPristophora conjugata (Dahlm.) larvae, andE. terebrator which killed 15.4% ofC. anastomosis population, the rest of the parasitoids occurred in low densities, and did not play an important role in reducing the number
of their hosts. 相似文献
109.
Gleyce de Oliveira Ferreira Valter Rodrigues Oliveira José Adalberto de Alencar Danillo Olegário Matos da Silva 《The Journal of Horticultural Science and Biotechnology》2017,92(5):550-558
This study aimed to evaluate onion accessions regarding their resistance to Thrips tabaci Lindeman, in order to enable the development of cultivars that are resistant to this pest. The experiments were carried out without chemical control, in a randomized block design with three replications, in Petrolina, PE and Juazeiro, BA. Six evaluations of thrips populations were carried out starting 15 days after transplanting, each one after 7 days. Simple correlations were estimated among all variables. Statistical differences were observed for the number of adults in different evaluations, while the number of nymphs showed no statistical differences. The largest average yields of commercial bulbs were observed for ‘Vale Ouro IPA 11?, ‘BRS Alfa São Francisco’, ‘Franciscana IPA 10? and ‘Sirius F1? while ‘Red Creole’, ‘Creole Mercosul’ and ‘Conquista’ had the lowest yield. The bulb commercial yield had simple negative correlations with nymph degree of infestation (DI) in the four evaluation phases and adult DIs at 22 days. Negative correlations between commercial bulb yield and central angle of the plant were observed, indicating that plants with higher bulb yield have a lower angle of the central leaves. The results of the study suggest that the resistance mechanism is due mainly to tolerance to the pest. 相似文献
110.
Sergey V. Popkov Leonid V. Kovalenko Mikhail M. Bobylev Oleg Yu. Molchanov Miron Z. Krimer Valery P. Tashchi Yury G. Putsykin 《Pest management science》1997,49(2):125-129
A number of substituted 2,2-dimethyl-6-arylidene-1-triazol-1-ylmethylcyclohexanols and 2,2-dimethyl-6-arylidene-1-imidazol-1-ylmethylcyclohexanols were prepared from 2-methylcyclohexanone in four steps: Claisen–Schmidt condensation with substituted benzaldehydes, methylation of the resulting 2-methyl-6-benzylidenecyclohexanones, conversion to the oxiranes by interaction with dimethylsulfonium methylide and reaction of the oxiranes with triazole or imidazole. The compounds obtained were tested for antifungal activity against five phytopathogenic fungi of different taxonomic classes. EC50 values were determined for all compounds. Structure–activity relationships are discussed in broad terms. Some of triazolymethyl-substituted cyclohexanols obtained are more active than triadimenol. © 1997 SCI. 相似文献