The impact of foliar fertilizers on growth and biochemical responses of Thymus vulgaris to salinity stress

Salinity reduces plant biomass and may lead to death when severe. To cope with the negative effects of this stress, plant species present specific physiological or biochemical responses. In this work, we hypothesized that spraying salt-stressed thyme leaves with K⁺ and Ca²⁺ could mitigate the negative effects of salinity on plant growth and metabolism. To test this hypothesis, we grew thyme plants under salinity stress for two and four weeks before applying foliar sprays. Also, to test the effect of stress relief, treated plants were allowed two weeks of recovery after four weeks of salt stress. In general, after two and four weeks of salinity stress, the leaf fresh weight of thyme plants was reduced by 31 and 43%, respectively. Salinity also decreased the relative water content, water, and osmotic potentials and led to ion imbalances and nutrient deficiencies. Salinity altered concentration of some essential oils, but leaf antioxidant contents remained fairly stable, except for a significant increase for plants under NaCl?+?KCl two weeks after treatment. Our results indicated that stressed plants accumulated significantly more soluble sugars and amino acids in comparison with the control. Foliar sprays with KCl and CaCl₂ reversed the negative effects of salinity on plant biomass and induced the accumulations of compatible solutes. Moreover, concentrations of some essential oils and gallic acid increased in sprayed plants, but these effects were dependent on the type and duration of the treatment. Overall, spraying leaves with K⁺ and Ca²⁺ was able to mitigate salinity stress in Thymus vulgaris even during the recovery period.     

Endometritis in she donkeys in Egypt

The endometrial necropsies of 165 she donkeys were examined and the endometria were classified into four grades according to histological features (I, IIa, IIb, III). Category I was observed in 86 cases (52.12%) and diagnosed as normal endometria. Category IIa was observed in 18 cases (10.91%) and diagnosed as slight endometritis. Category IIb was observed in 28 cases (16.97%) and diagnosed as moderate endometritis (two to four nests/field), while category III was observed in 33 cases (20%) and diagnosed as severe endometritis (eight nests/field). A bacteriological examination was carried out and oestrogen and progesterone were estimated. Our results indicate that endometritis and the prognosis of fertility in she donkeys were more or less parallel to mares.     

Histopathological studies on neoplasms in the genital tract of female donkeys in Egypt.

The genital tracts of 165 female donkeys were collected and examined with special concern to neoplasms. Ovarian Neoplasms were found in 12 cases (7.72%). A granulosa cell tumor was found in one case (0.61%). A cavernous haemangioma was found in 11 cases (6.67%). Uterine neoplasms were found in 14 cases (8.84%). Endometrial polyps and fibroleiomyoma were found in one case (0.61%) each. Leiomyoma was found in 2 cases (1.21%). Cavernous haemangioma was found in 10 cases (6.06%), and cervical polyps in 5 cases (3.03%).     

Wild ostrich (<Emphasis Type="Italic">Struthio camelus australis</Emphasis>) reproduction in Orbata,a nature reserve in Tunisia

The aim of the current investigation was to determine wild ostrich reproductive behaviour in Orbata Nature Reserve by observing 16 hens and 28 cocks over a seven-year period. Intense laying commenced in January, one month after the cessation of the rainy season, and 92% of the eggs were produced during the dry season (January to May, peaking in March). Over the seven years, 1,322 eggs were laid in 69 nests, which corresponded to an annual average production of 19.2 ± 9.1 eggs/nest and 11.8 eggs/hen. 24 nests (34.78%) were non-brooded, 17 nests (24.64%) were deserted in the course of incubation, and 28 nests (40.58%) possessed hatched eggs. All the non-incubated nests had egg losses equivalent to 46.6 ± 12.6%. Hatchability success of incubated eggs was 41.9 ± 12.0%. Ostriches tended to dig their nests adjacent to the reserve enclosure which had direct access by road and track, the latter subjecting them to human disturbance and predation. The systematic obstruction of these nests stimulated ostriches to build additional nests within the reserve perimeter. The authors discussed the results recorded in an ostrich flock in relation to the environmental factors (climatic factors, food disponibility and predation) and suggested possibilities for improved wildlife management.     

Biochemical and histological effects of gibberellic acid on Locusta migratoria migratoria fifth instar larvae

Experiments were conducted to assess the effect of gibberellic acid (GA₃), a plant growth regulator, on Locusta migratoria migratoria fifth instar larvae. Newly emerged larvae were exposed to various concentrations of GA₃ administered by topical application or by forced ingestion. Results showed that treated insects exhibited toxic symptoms with a dose-dependent mortality. GA₃ toxicity was also demonstrated by perturbation of the moult processes. In fact, we noted that treated insects present exuviations difficulties due to the impossibility to reject the old integuments causing mortality in the 5th instar larvae. Histological study of proventriculus revealed alterations in the epithelial cells and absence of apolysis phenomenon. Data also showed that GA₃ induced significant quantitative variation of haemolymph metabolites. These changes result in a significant decrease in the total concentration of proteins and carbohydrates and an increase in the total concentration of haemolymph lipids.     

Effects of gibberellic acid on ovarian biochemical composition and ecdysteroid amounts in the migratory locust Locusta migratoria (Orthoptera,Acrididae)

Migratory locusts represent the most important crop pests in Africa and Asia. Because environmental damages are associated with the use of synthetic insecticides in locust and grasshopper control, new environmentally acceptable approaches are becoming increasingly important. The effects of gibberellic acid (GA₃), a plant growth regulator, was investigated by topical application and ingestion on the reproductive physiology and ecdysteroids production of the migratory locust Locusta migratoria at concentrations of 125, 625, 3125, 4125, 5125 and 6125 μg/mL. The treatment applied to adult females during the pre-ovipositional phase provokes a significant adverse influence on their reproductive potential. Indeed, GA₃ significantly reduced both fecundity and fertility. Gibberellic acid also caused disturbances in the incorporation of the hemolymph metabolites (proteins, carbohydrates and lipids) in the oocyte resulting in a significant reduction in their concentrations in the ovaries. Ecdysteroid production was measured by an enzymo-immunoassay. GA₃, administered by ingestion to the adult females, significantly reduced the ecdysteroid titers in ovaries and freshly laid eggs.     

Spinning of polyacrylamidoximes by solution blowing technique: Synthesis and characterization

A novel route for the production of polyacryloamidoxime nano-fibers is described. The innovative solution blowing spinning technique is used for the production of polyacryloamidoxime nano-fibers. The polyacryloamidoxime was prepared by the amidoximation of the acrylonitrile groups in a non-aqueous medium (DMF) using the least possible amount of hydroxylamine. A comparison study was performed to evaluate the effectiveness of the amidoximation reaction in aqueous or non-aqueous media. As the presented method is acquiring only 0.5 g/g hydroxylamine, at 50 °C for 7 h to achieve 63.1 % conversions, also solution blowing is an alternative technique for manufacturing of micro- and nano-fibers. The morphological structure, the chemical nature as well as the dyeability of the obtained fibers are illustrated. The obtained nano polyacryloamidoxime fibers show superior adsorption ability toward copper ions. Results showed that the present work presents a promising synthesis root for spinnable polyacryloamidoxime.     

Feeding perturbation and toxic activity of five Chrysanthemum species crude extracts against Spodoptera littoralis (Boisduval) (Lepidoptera; Noctuidae)

The effect of the whole methanol extracts of five Chrysanthemum species on feeding and performance of Spodoptera littoralis (Boisduval) larvae has been investigated in vitro. The extracts exhibited an anti-feeding and phagostimulating activities against cotton leafworm larvae when applied either on leaf discs or incorporated into an artificial diet. Under chosen conditions, the antifeedant index calculated over 24 h for sixth instar larvae significantly varied from 78.55 for Chrysanthemum segetum L. to −44.18 for Chrysanthemum fuscatum Desf. at the dose of 1000 ppm. Toxicity of the extracts was manifested by a high mortality, reduced growth rates, and low weight gain by larvae fed on diets containing 1000–10,000 ppm of the extract. Anyone of the larvae treated with Chrysanthemum macrotum (D.R.) Ball. leaves crude extract survived to pupation at the two higher concentrations. The time to pupation increased for Chrysanthemum grandiflorum flowers crude extract from 11.40 ± 0.93 to 28.93 ± 10.92 days as the extract concentration in the diet increased from 0 to 10,000 ppm. The ingestion of crude extract by the third instar larvae reduced significantly the consumption, growth and utilisation of the ingested and digested food, and reduced digestibility.     

Recent sedimentation rates in Garaet El Ichkeul Lake, NW Tunisia, as affected by the construction of dams and a regulatory sluice

Purpose

Ichkeul National Park, NW Tunisia, is a UNESCO Biosphere Reserve. Garaet El Ichkeul Lake is known for its seasonal variability in water level and salinity. In recent decades, the waterbody has been affected by the construction of new hydraulic structures. To reduce the impacts of dams and to maintain the sustainability of the ecosystem, a sluice was built at the outlet of the lake, and it operated for the first time in 1996. This paper describes an investigation of recent sedimentation dynamics in Ichkeul Lake, determined by radiometric dating of sediment cores.

Materials and methods

A sediment core was collected with a UWITEC gravity corer at the deepest, central part of the lake in August 2009. Specific activities of unsupported lead-210 (²¹⁰Pb) and caesium-137 (¹³⁷Cs) were measured in the core, enabling calculation of recent sediment accumulation rates (SAR). Published radiometric data from nearby sediment cores, collected in 1997 and 1982, provide a comparison.

Results and discussion

The measured excess ²¹⁰Pb inventory was 5300?±?500?Bq?m^?2, leading to an estimation of constant flux of 165?±?16?Bq?m^?2?yr^?1, a value higher than the best estimate for local atmospheric fluxes (123?±?12?Bq?m^?2?yr^?1) and the flux estimated from the core collected in 1982 (48?Bq?m^?2?yr^?1). The ¹³⁷Cs inventory was 3550?±?120?Bq?m^?2, two times higher than the historical ¹³⁷Cs atmospheric deposition in the area. The ¹³⁷Cs profile displayed a distinct peak, but the ¹³⁷Cs depth-distribution did not follow the pattern expected from atmospheric deposition. Application of the constant rate of supply (CRS) model, with the reference point method, produced a chronology and SAR values comparable to those found in previous work. The whole ¹³⁷Cs profile was quantitatively reconstructed from the historical records of atmospheric deposition, using the system-time-averaged (STA) model.

Conclusions

The CRS and STA models provide consistent sediment accumulation results for the whole data set, considering the time resolution of the chronology (~6?years) and analytical uncertainties. Results from cores sampled in 1982, 1997 and 2009 reveal an increasing SAR trend, from ~0.25?g?cm^?2?yr^?1 in the early 1940s to ~0.67?g?cm^?2?yr^?1 at present. In the 13?years since installation of sluice gates at Tinja, SAR in the central Ichkeul Lake has not declined. Thus, if siltation continues at the present rate, shallowing of the lake will seriously affect the hydromorphology and ecology of this important lake.