Amal Y. Aldhebiani

Soil Erosion Estimation Using Remote Sensing Techniques in Wadi Yalamlam Basin, Saudi Arabia

Soil erosion is one of the major environmental problems in terms of soil degradation in Saudi Arabia. Soil erosion leads to significant on- and off-site impacts such as significant decrease in the productive capacity of the land and sedimentation. The key aspects influencing the quantity of soil erosion mainly rely on the vegetation cover, topography, soil type, and climate. This research studies the quantification of soil erosion under different levels of data availability in Wadi Yalamlam. Remote Sensing (RS) and Geographic Information Systems (GIS) techniques have been implemented for the assessment of the data, applying the Revised Universal Soil Loss Equation (RUSLE) for the calculation of the risk of erosion. Thirty-four soil samples were randomly selected for the calculation of the erodibility factor, based on calculating the -factor values derived from soil property surfaces after interpolating soil sampling points. Soil erosion risk map was reclassified into five erosion risk classes and 19.3% of the Wadi Yalamlam is under very severe risk (37,740 ha). GIS and RS proved to be powerful instruments for mapping soil erosion risk, providing sufficient tools for the analytical part of this research. The mapping results certified the role of RUSLE as a decision support tool.

Impact of application of zinc oxide nanoparticles on callus induction, plant regeneration, element content and antioxidant enzyme activity in tomato (Solanum lycopersicum Mill.) under salt stress

The properties of nanomaterials and their potential applications have been given considerable attention by researchers in various fields, especially agricultural biotechnology. However, not much has been done to evaluate the role or effect of zinc oxide nanoparticles (ZnO-NPs) in regulating physiological and biochemical processes in response to salt-induced stress. For this purpose, some callus growth traits, plant regeneration rate, mineral element (sodium, potassium, phosphorous and nitrogen) contents and changes in the activity of superoxide dismutase (SOD) and glutathione peroxidase (GPX) in tissues of five tomato cultivars were investigated in a callus culture exposed to elevated concentrations of salt (3.0 and 6.0 g L -1 NaCl), and in the presence of zinc oxide nanoparticles (15 and 30 mg L -1 ). The relative callus growth rate was inhibited by 3.0 g L -1 NaCl; this was increased dramatically at 6.0 g L -1 . Increasing exposure to NaCl was associated with a significantly higher sodium content and SOD and GPX activities. Zinc oxide nanoparticles mitigated the effects of NaCl, and in this application of lower concentrations (15 mg L -1 ) was more effective than a higher concentration (30 mg L -1 ). This finding indicates that zinc oxide nanoparticles should be investigated further as a potential anti-stress agent in crop production. Different tomato cultivars showed different degrees of tolerance to salinity in the presence of ZnO-NPs. The cultivars Edkawy, followed by Sandpoint, were less affected by salt stress than the cultivar Anna Aasa. DOI: 10.2298/ABS151105017A Key words : Nano biotechnology, in vitro culture, protein, salinity, superoxide dismutase, glutathione peroxidase Received: November 5, 2015; Revised: February 11, 2016; Accepted: February 12, 2016; Published online: March 21, 2016 How to cite this article: Alharby HF, Metwali EMR, Fuller MP, Aldhebiani AY. Impact of application of zinc oxide nanoparticles on callus induction, plant regeneration, element content and antioxidant enzyme activity in tomato (Solanum lycopersicum Mill.) under salt stress. Arch Biol Sci. 2016;68(4):723-35.

The alteration of mRNA expression of SOD and GPX genes, and proteins in tomato (Lycopersicon esculentum Mill) under stress of NaCl and/or ZnO nanoparticles.

Five cultivars of tomato having different levels of salt stress tolerance were exposed to different treatments of NaCl (0, 3 and 6 g L−1) and ZnO-NPs (0, 15 and 30 mg L−1). Treatments with NaCl at both 3 and 6 g L−1 suppressed the mRNA levels of superoxide dismutase (SOD) and glutathione peroxidase (GPX) genes in all cultivars while plants treated with ZnO-NPs in the presence of NaCl, showed increments in the mRNA expression levels. This indicated that ZnO-NPs had a positive response on plant metabolism under salt stress. Superior expression levels of mRNA were observed in the salt tolerant cultivars, Sandpoint and Edkawy while the lowest level was detected in the salt sensitive cultivar, Anna Aasa. SDS–PAGE showed clear differences in patterns of protein expression among the cultivars. A negative protein marker for salt sensitivity and ZnO-NPs was detected in cv. Anna Aasa at a molecular weight of 19.162 kDa, while the tolerant cultivar Edkawy had two positive markers at molecular weights of 74.991 and 79.735 kDa.

Species concept and speciation

Defining and recognizing a species has been a controversial issue for a long time. To determine the variation and the limitation between species, many concepts have been proposed. When a taxonomist study a particular taxa, he/she must adopted a species concept and provide a species limitation to define this taxa. In this paper some of species concepts are discussed starting from the typological species concepts to the phylogenetic concept. Positive and negative aspects of these concepts are represented in addition to their application.

Stream network pollution by olive oil wastewater risk assessment in Crete, Greece

Abstract Discharge of olive mill wastewater (OMWW) into rivers system in Crete had led to heavy organic pollution and several drastic environmental impacts. The current research study aims to map and evaluate the environmental hazards initiated by olive mill wastewater pollution discharged into surface stream network of Kolymvari agricultural area located in western Crete, Greece. Implemented methodology is based on locating source points of pollution and determining pollutant surface flow paths under GIS environment. Hydrological features of the area were delineated in the GIS environment using basically elevation data provided by the Ministry of Agriculture. On a microscale, it was proved that the implementation of MCA can quantify the environmental risk to surface water resources caused by OMWW. On a macroscale, risk mapping was implemented by establishing a spatial connection between the source points of pollution and the possible sedimentation areas. Furthermore, mapping of olive mill waste tanks will positively improve the exercised methodology in term of assessing the potential risks of soil and groundwater pollution.

Silicon and its application method effects on modulation of cadmium stress responses in Triticum aestivum (L.) through improving the antioxidative defense system and polyamine gene expression

Identification of the optimum application method of exogenous supports for crop plants to improve their growth under environmental stresses such as heavy metals represents key priorities for researchers worldwide. Influences of different application methods of silicon (Si; 3 mM); soil treatment, foliar spray and seed soaking on growth, chlorophyll fluorescence, photosynthetic gas exchange, cell membrane injury, osmoprotectants contents, antioxidative defense system activity, and polyamines contents and their gene expression in wheat plants grown under normal and 2 mM cadmium (Cd) stress conditions were investigated in 3-repeated pot experiment. Cd stress severely depressed growth, chlorophyll fluorescence, photosynthetic gas exchange, tissue health, water use efficiency (WUE) and Si content, and elevated osmoprotectants and Cd2+ contents, antioxidative defense system activity, and polyamines contents and their gene expression. However, Si in different application methods alleviated the Cd stress effects and significantly reduced Cd2+ and MDA contents and electrolyte leakage, significantly increased growth, chlorophyll fluorescence, photosynthetic gas exchange, WUE, membrane stability index, relative water content and Si content, and further increased proline and soluble sugars contents, antioxidative (enzymatic and non-enzymatic) defense system activity, and polyamines contents and their gene expression. Among the three methods, Si applied as soil addition was the best and most effective in alleviating the Cd stress effects.

Effect of Cucumber mosaic virus (CMV) infection on antineoplastic alkaloids from periwinkle (Catharanthus roseus L.) cultured in the Mecca region and resistance induction by plant-growth-promoting rhizobacteria (PGPR)

ABSTRACT More than 100 alkaloids have been found in periwinkle, of which vincristine and vinblastine are the most notable for the treatment of diseases such as leukaemia. In this study, characterization of naturally occurring Cucumber mosaic virus (CMV) infection showed mosaic, leaf deformation and stunting of plants. Viral identification was confirmed by double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) with a specific CMV polyclonal antibody and reverse transcription PCR with a specific primer for the CMV-RdRp-gene, which yielded a 513 base pair DNA fragment. The effect of CMV infection on the antineoplastic alkaloids in periwinkle leaves was determined. We also studied the effect of using plant-growth-promoting rhizobacteria (PGPR) isolates against virus infection to stimulate resistance induction in host plants. Bacillus subtilis 281 and B. pumilus 293 were examined individually (B1 and B2) and in a mixture (B1&B2) for their effectiveness against infection with CMV. The results of greenhouse experiments were confirmed by artificial mechanical inoculation. The PGPR strain treatments and results were reinforced by analysing the protein patterns as well as determining the total phenol, total flavonoid and total alkaloid contents. PGPR treatment evidently lowered the virus concentrations, the percentage of infected plants and the disease severity compared with healthy and infected controls. Seedlings treated with the B1&B2 strain mixture yielded significantly lower levels of virus infection than B1 or B2 individually in all experiments compared to controls. Our findings demonstrate the possibility of using selected Bacillus spp. strains to induce systemic resistance for CMV infection control.

Inhibitory activity of different medicinal extracts from Thuja leaves, ginger roots, Harmal seeds and turmeric rhizomes against Fig leaf mottle-associated virus 1 (FLMaV-1) infecting figs in Mecca region

Fig leaf mottle-associated virus-1 (FLMaV-1) is a closterovirus newly identified in fig trees, in the Mecca region, suffering from mosaic disease symptoms and apparently is compromising the fig plantation in the country. In the present study, we demonstrated the efficiency of two in vivo experiments including pre and post treatments using Thuja leaf, ginger roots, Harmal seeds and turmeric rhizome extracts on symptoms expression of rooted cuttings infected with FLMaV-1- and their impact on virus multiplication. Results showed that individual treatments with ginger roots and turmeric rhizomes in pre-grafting experiments and Thuja extract following Harmal seeds in post grafting experiments were efficient against symptom development. In addition, results showed that the total photosynthesis pigments; total soluble intracellular proteins and total phenol contents were higher in infected treated cuttings compared with healthy ones, thus it was taken as evidence on a mutual interaction between these extracts and virus multiplication.