In Tunisia, Orobanche foetida Poir. is considered an important agricultural biotic constraint on faba bean (Vicia faba L.) production. An innovative control method for managing this weed in faba bean ...is induced resistance through inoculation by rhizobia strains. In this study, we explored the biochemical dynamics in V. faba L. minor inoculated by rhizobia in response to O. foetida parasitism. A systemic induced resistant reaction was evaluated through an assay of peroxidase (POX), polyphenol oxidase (PPO) and phenyl alanine ammonialyase (PAL) activity and phenolic compound and hydrogen peroxide (H2O2) accumulation in faba bean plants infested with O. foetida and inoculated with rhizobia. Two rhizobia strains (Mat, Bj1) and a susceptible variety of cultivar Badi were used in a co-culture Petri dish experiment. We found that Mat inoculation significantly decreased O. foetida germination and the number of tubercles on the faba bean roots by 87% and 88%, respectively. Following Bj1 inoculation, significant decreases were only observed in O. foetida germination (62%). In addition, Mat and Bj1 inoculation induced a delay in tubercle formation (two weeks) and necrosis in the attached tubercles (12.50% and 4.16%, respectively) compared to the infested control. The resistance of V. faba to O. foetida following Mat strain inoculation was mainly associated with a relatively more efficient enzymatic antioxidative response. The antioxidant enzyme activity was enhanced following Mat inoculation of the infected faba bean plant. Indeed, increases of 45%, 67% and 86% were recorded in the POX, PPO and PAL activity, respectively. Improvements of 56% and 12% were also observed in the soluble phenolic and H2O2 contents. Regarding inoculation with the Bj1 strain, significant increases were only observed in soluble phenolic and H2O2 contents and PPO activity (especially at 45 days after inoculation) compared to the infested control. These results imply that inoculation with the rhizobia strains (especially Mat) induced resistance and could bio-protect V. faba against O. foetida parasitism by inducing systemic resistance, although complete protectionwas not achieved by rhizobia inoculation. The Mat strain could be used as a potential candidate for the development of an integrated method for controlling O. foetida parasitism in faba bean.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In Tunisia, Orobanche foetida Poir. is considered an important agricultural biotic constraint on faba bean (Vicia faba L.) production. An innovative control method for managing this weed in faba bean ...is induced resistance through inoculation by rhizobia strains. In this study, we explored the biochemical dynamics in V. faba L. minor inoculated by rhizobia in response to O. foetida parasitism. A systemic induced resistant reaction was evaluated through an assay of peroxidase (POX), polyphenol oxidase (PPO) and phenyl alanine ammonialyase (PAL) activity and phenolic compound and hydrogen peroxide (H.sub.2 O.sub.2) accumulation in faba bean plants infested with O. foetida and inoculated with rhizobia. Two rhizobia strains (Mat, Bj1) and a susceptible variety of cultivar Badi were used in a co-culture Petri dish experiment. We found that Mat inoculation significantly decreased O. foetida germination and the number of tubercles on the faba bean roots by 87% and 88%, respectively. Following Bj1 inoculation, significant decreases were only observed in O. foetida germination (62%). In addition, Mat and Bj1 inoculation induced a delay in tubercle formation (two weeks) and necrosis in the attached tubercles (12.50% and 4.16%, respectively) compared to the infested control. The resistance of V. faba to O. foetida following Mat strain inoculation was mainly associated with a relatively more efficient enzymatic antioxidative response. The antioxidant enzyme activity was enhanced following Mat inoculation of the infected faba bean plant. Indeed, increases of 45%, 67% and 86% were recorded in the POX, PPO and PAL activity, respectively. Improvements of 56% and 12% were also observed in the soluble phenolic and H.sub.2 O.sub.2 contents. Regarding inoculation with the Bj1 strain, significant increases were only observed in soluble phenolic and H.sub.2 O.sub.2 contents and PPO activity (especially at 45 days after inoculation) compared to the infested control. These results imply that inoculation with the rhizobia strains (especially Mat) induced resistance and could bio-protect V. faba against O. foetida parasitism by inducing systemic resistance, although complete protectionwas not achieved by rhizobia inoculation. The Mat strain could be used as a potential candidate for the development of an integrated method for controlling O. foetida parasitism in faba bean.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Hydrated sodium calcium aluminosilicate (HSCAS), an anticaking agent for mixed feed, was added alone or simultaneously with a toxic Zearalenone (ZEN) dose to balb/c mice and was evaluated for its ...ability to restore damages induced by ZEN. The latter is a mycotoxin produced by fusarium genera; it is mainly known to induce several toxic effects such as hepatotoxicity, immunotoxicity and nephrotoxicity on animals and humans. The experimental approach consisted of eight treatments of six mice each by 400
mg/kg bw or 5
g/kg bw of HSCAS. Two experimental groups have received respectively ZEN alone at 40 (8% of LD
50) and at 500
mg/kg bw (LD
50). Two other groups have received ZEN at 40 or 500
mg/kg bw combined respectively with HSCAS at 400
mg/kg bw and 5
g/kg bw. The control groups received water or olive oil. Forty-eight hours after treatment, blood samples were collected for haematological and serum biochemical parameters measurements. ZEN treatment significantly increased hematocrit, haemoglobin, white blood cells: lymphocytes, eosinophils, neutrophils, monocytes and the most of biochemical serum parameters; it significantly reduced platelets and induced degenerative changes in the hepatic and renal tissues; while, the mixture of HSCAS with ZEN induced a reestablishment of haematological parameters, levels of serum biochemical enzyme activities and histological pictures of both liver and kidney. It also prevented general toxicity of ZEN. This was observed by the shift of LD
50 for this toxin.
Thus, our data strongly suggested that deleterious effects of ZEN could be overcome or, at least, significantly were diminished by HSCAS. Moreover, this sorbent by itself did not show any toxic effects.
First-principles approach is used to study the structural, electronic and magnetic properties of CoMnCrZ (Z = Al, Si, Ge and As) quaternary Heusler compounds, using full-potential linearized ...augmented plane wave (FP-LAPW) scheme within the generalized gradient approximation (GGA). The computed equilibrium lattice parameters agree well with the available theoretical data. The obtained negative formation energy shows that CoMnCrZ (Z = Al, Si, Ge, As) compounds have strong structural stability. The elastic constants
C
ij
are calculated using the total energy variation with strain technique. The polycrystalline elastic moduli (namely: the shear modulus, Young’s modulus, Poisson’s ratio, sound velocities, Debye temperature and melting temperature were derived from the obtained single-crystal elastic constants. The ductility mechanism for the studied compounds is discussed via the elastic constants
C
ij
. Our calculations with the GGA approximation predict that CoMnCrGe, CoMnCrAl, CoMnCrSi and CoMnCrAs are half-metallic ferrimagnets (HMFs) with a half-metallic gap
E
HM
of 0.03 eV, 0.19 eV, 0.34 eV and 0.50 eV for, respectively. We also find that the half-metallicity is maintained on a wide range of lattice constants.
In this study, metal foam heat sinks (MFHS) are proposed for thermal management of electronic devices. Metal foams are excellent candidates for improving the heat transfer performance of heat sinks ...due to their unique characteristics such as the large surface area to volume ratio and their complex form, which favors mixing and convection. Numerical investigations of the transient thermal-hydraulic behavior and performance of the cooling process of electronic devices by MFHS are carried out. The physical model consists of a convective laminar air flow inside a channel equipped with multiple power electronic devices cooled by MFHS. MFHS consist of three plate fin heat sinks which are made of aluminum foam with a porosity of 0.95 and a permeability of 1.65107 m2, and the heat sink base is made of aluminum solid. Comsol software is used to solve the governing equations. Numerical results reveal that the thermal performance of MFHS is larger than that of a conventional heat sink and a clear channel under the same operating conditions, and the thermal behavior of electronic devices cooled by MFHS is stable and maintained at admissible temperatures. The validation of the numerical results shows perfect agreement with the experimental data with a maximum relative error of 3 %.
Soil microorganisms play an important role in maintaining natural ecological balance through active participation in carbon, nitrogen, sulfur, and phosphorous cycles. Phosphate-solubilizing bacteria ...(PSB) are of high importance in the rhizosphere, enhancing the solubilization of inorganic phosphorus complexes into soluble forms available for plant nutrition. The investigation of this species of bacteria is of major interest in agriculture, as they can be used as biofertilizers for crops. In the present study, 28 isolates of PSB were obtained after the phosphate enrichment of soil samples from five Tunisian regions. Five PSB species were identified by 16S rRNA gene sequencing including
,
, and
,
, and
. Solid and liquid Pikovskaya's (PVK) and National Botanical Research Institute's (NBRIP) media containing insoluble tricalcium phosphate were used for the evaluation of the phosphate solubilization ability of the bacterial isolates by two methods: visual evaluation of the solubilization zone around colonies (halo) and determination of solubilized phosphates in liquid medium by the colorimetric method of the vanado-molybdate yellow. Based on the results of the halo method, the isolate of each species that showed the higher phosphate solubilization index was selected for evaluation of phosphate solubilization by the colorimetric method. In the liquid media, the bacterial isolates showed phosphate solubilization ranging from 535.70 to 618.57 µg mL
in the NBRIP medium, and 374.20 to 544.28 µg mL
in the PVK medium, with the highest values produced by
. The best phosphate solubilization ability and higher reduction in broth pH, which indicates higher organic acid production, were achieved in NBRIP broth for most of the PSB. Strong correlations were observed between the average capability of PSB to solubilize phosphates and both the pH and total phosphorous content in the soil. The production of the hormone indole acetic acid (IAA), which can promote plant growth, was observed for all five PSB species. Among them,
obtained from the forest soil of northern Tunisia showed the highest production of IAA (50.4 ± 0.9 µg mL
).
