Corn Wastes and Peanut Shell as Growing Media for Production of Red Radish Plants in Soilless System

ABSTRACT

Peat is considered the conventional growing medium in most soilless culture systems. The high cost of peat and the urgent need of agricultural wastes recycling encouraged the scientists and soilless culture users to search for an alternative growth medium where optimal growth conditions are achieved and help in the safe disposal of wastes. In the current study, peanut shell (PS) and corn wastes (CW) were used as growing media in comparison to peat moss (PM). The tested organic wastes and peat moss were examined with sand at three mixing ratios (1:1 “M₁”, 1:2 “M₂” and 1:3 “M₃” raw material: washed sand, respectively). Red radish (Raphanus raphanistrum subsp. sativus) plant were cultivated in 5 kg pots filled with the instigated growing media. Most of the recoded growth parameters were found in PS and PM growing media, while the lowest ones were found in CW. PS medium contained available N and P higher by 141 and 29% above the PM media. Although the peat moss gave the highest values in the measured growth characteristics, its high price decreased the net profit. The highest net profit value was obtained from PSM₂ followed by PSM₁ and PSM₃. According to the obtained results, the characteristics of the growth media derived from peanut shell qualify them for use in the production of red radish in soilless culture systems.     

Chemical composition of volatile extract and biological activities of volatile and less-volatile extracts of juniper berry (Juniperus drupacea L.) fruit

Volatile chemicals in a dichloromethane extract from a steam distillate of juniper berry fruit (Juniperus drupacea L.) and its two column chromatographic fractions (eluted with hexane and ethyl ether) were analyzed by gas chromatography/mass spectrometry. The major compounds in the dichloromethane extract were alpha-pinene (23.73%), thymol methyl ether (17.32%), and camphor (10.12%). A fraction eluted with hexane contained alpha-pinene (44.24%) as the major constituent. A fraction eluted with ethyl ether had thymol methyl ether (22.27%) and camphor (19.65%) as the main components. Three samples prepared from the distillate and two additional samples prepared by petroleum ether and ethanol extraction directly from juniper berry fruits exhibited clear antioxidant activities with dose response in both 1,2-diphenyl picrylhydrazyl and beta-carotene assays. All samples except the hexane fraction showed comparable activities to that of the synthetic antioxidant t-butyl hydroquinone at a level of 200 microg/mL in the two testing systems. The extracts of dichloromethane, petroleum ether, and ethanol exhibited appreciable antimicrobial activities against six microorganisms with minimum inhibitory concentrations ranging from 0.5 mg/mL (volatile extract against Candida albicans ) to 1.2 mg/mL (ethanol extract against Aspergillus niger ). The results of the present study suggest that this fruit could be a natural antioxidant supplement for foods and beverages.     

Biological control of Sclerotinia minor using a chitinolytic bacterium and actinomycetes

Isolates of 85 bacteria and 94 streptomycete and 35 nonstreptomycete actinomycetes were obtained from a lettuce-growing field in Al-Ain, United Arab Emirates, on colloidal chitin agar, and screened for their ability to produce chitinase. Twenty-three bacteria and 38 streptomycete and 15 nonstreptomycete actinomycete isolates produced high levels of chitinase and were examined in vitro for their ability to suppress the growth of Sclerotinia minor , a pathogen causing basal drop disease of lettuce. The three most suppressive isolates were examined further for their production of β-1,3-glucanase and antifungal activity as well as their ability to colonize the roots and rhizosphere of lettuce in vitro and in planta . The three isolates, Serratia marcescens, Streptomyces viridodiasticus and Micromonospora carbonacea , significantly reduced the growth of S. minor in vitro , and produced high levels of chitinase and β-1,3-glucanase. Streptomyces viridodiasticus also produced antifungal metabolite(s) that significantly reduced the growth of the pathogen in vitro . When the pathogen was presented as the sole carbon source, all three isolates caused extensive hyphal plasmolysis and cell wall lysis. Serratia marcescens and St. viridodiasticus were competent to varying degrees in colonizing the roots of lettuce seedlings after 8 days on agar plates and the rhizosphere within 14 days in pots, with their competency being superior to that of M. carbonacea . All three isolates, individually or in combination, were antagonistic to S. minor and significantly reduced incidence of disease under controlled glasshouse conditions.     

The black fig fly Silba adipata (Diptera: Lonchaeidae) as an emerging pest in Tunisia: preliminary data on geographic distribution,bioecology and damage

Phytoparasitica - Frugivorous fruit flies are considered among the most damaging pests of cultivated fruit crops. The most studied ones are those belonging to the Tephritidae family such as the...     

From in vitro hepatic metabolic studies towards human health risk assessment: Two case studies of diuron and carbosulfan

Risk assessment of environmental pollutants is an absolutely essential tool in the overall process of protecting public health. Risk assessment needs reliable scientific information and one source of information is the characterization of metabolic fate and toxicokinetics of environmental pollutants. The aim of in vitro characterization is to produce relevant information on metabolism and interactions to anticipate and ultimately predict what happens in vivo in humans. Because human data is most appropriate to improve human risk assessment, the best option is to rely upon human-derived in vitro models and obtain quantitative toxicokinetics data from in vitro systems for the comparison between species or individuals. In short, based on our studies of pesticide metabolism and interactions, we have used in vitro metabolism data in human and animal hepatic in vitro models and clearance testing data to calculate chemical-specific adjustment factors, instead of fixed uncertainty factors, to be employed as an alternative and more realistic model for human health risk assessment of pesticides and other environmental pollutants.     

Effects of nymphal density (Bactericera trigonica) and feeding on photosynthetic pigments,proline content and phenolic compounds in carrot plants

European Journal of Plant Pathology - Insect feeding induces physiological and biochemical changes in host plants. Indeed, symptom severity often depends on insect density. Recently, the carrot...     

Development of resistance and cross-resistance in fenvalerate and deltamethrin selected strains of Spodoptera littoralis (Boisd.)

Resistances of 33- and 27-fold to the pyrethroids fenvalerate and deltamethrin, respectively, have been induced in larvae of the Egyptian cotton leafworm Spodoptera littoralis (Boisd.) by selection of two subcolonies of a field population in the laboratory. Selected strains showed relatively high levels of resistance (11- to 36-fold) to all the tested pyrethroids, moderate levels of cross-resistance (3- to 13-fold) to DDT and the carbamate aminocarb, and a slight increase in tolerance levels to endrin and lindane. The pyrethroid-resistant strains, by contrast, manifested no cross-resistance to the organophosphorus compounds that were tested. Moreover, a negative crossresistance was observed in the pyrethroid-resistant strains to dicrotophos, methamidophos and the carbamate methomyl.     

Pathology and molecular diagnosis of paratuberculosis of camels

Camels are the prime source of meat and milk in many desert regions of the world including Saudi Arabia. Paratuberculosis of camels, locally called Silag, is a serious and invariably fatal disease in the Arabian camel. Six camels were used in this study. Five camels with clinical paratuberculosis were used to study the pathology of the disease and confirm its aetiology. The sixth camel was clinically healthy and used as a control. The camels were examined clinically and bled for haematological and blood chemistry analysis. They were then humanely killed with a high intravenous dose of thiopental sodium (10 mg/kg) for pathological studies as well as obtaining tissues for microbiological and molecular studies. The clinical signs of the disease were emaciation, diarrhoea, alopecia, wry neck and pale mucous membranes. Laboratory diagnosis showed reduced haemoglobin concentration, low haematocrit and high activity of the serum enzyme alanine aminotransferase. Serum creatinine concentration was normal. These results indicated the infected camels were anaemic and the function of their livers was affected. Postmortem examination showed thickened and corrugated intestinal mucosa, enlarged granulomatous mesenteric lymph nodes, miliary and diffuse granulomas in the liver (in four camels), generalized lymph node granulomas (in one camel), splenic granuloma (in one camel) and mediastinal lymph node granuloma (in two camels). Histopathological examination showed diffuse infiltration of macrophages in all organs showing lesions. Ziehl–Neelsen staining of tissue scraping and tissue sections showed masses of acid fast bacilli, except for the spleen. Infection with Mycobacterium avium subsp. paratuberculosis was confirmed by PCR by targeting the IS900 gene.     

Phylogenetic relationships in grey mullets (Mugilidae) in a Tunisian lagoon

The Mugilidae family is an important fish group representing a major source for fisheries and aquaculture. In the south Mediterranean bank, no data are available on this fauna, except for some morphological studies on Tunisian samples. In this study, 16 allozymic loci were used to investigate the phylogenetic relationships within Tunisian mugilids. The results obtained from Hergla lagoon samples highlight five operational taxonomic unit corresponding to the well‐known species (Liza aurata, Liza ramada, Liza saliens, Chelon labrosus, Mugil cephalus). Several loci appeared to be diagnostic of these species, but in contrast to Greek mugilid samples, we did not find any diagnostic locus fixed differently for the five species. These results can help aquaculture units to identify accurately the mullet species they subsequently use for stocking aquaculture ponds and inland waters. However, species identity represents very important information, as each species has a different growth rate and salinity tolerance. On the other hand, when compared with North Mediterranean Mugilidae analysed until now, Tunisian samples show a genetic differentiation that could be related to different physicochemical conditions between the North and South banks, similar to those recorded in the eastern and western two Mediterranean basins separated by the Siculo‐Tunisian strait. In addition, this study confirms the morphological taxonomy, except for the subdivision of the Liza genus into two sub‐genera. The phylogenetic tree is in agreement with that on Languedoc Mugilidae samples (France), indicating that the subdivision of the Liza genus into two sub‐genera appears to be without any genetic base.     

Suspended-sediment transport in an intensively cultivated watershed in southeastern California

The purpose of this study is to investigate the variation of sediment movement at multiple spatial and two temporal scales of an agricultural watershed in southeastern California where surface runoff is primarily supplied by irrigation. An extensive turbidity and stage monitoring program based on grab sampling using 500-mL plastic bottles and in situ monitoring using both turbidity sensors and pressure transducers was designed to capture the spatial and temporal heterogeneities of suspended-sediment loads. The obtained turbidity values and stages at weekly and 5-min time scales were subsequently converted to suspended-sediment concentrations and water discharges, respectively, using established calibration methods. Weekly data were analyzed using a mass-balance approach to distinguish erosion and deposition processes in drain channels at various spatial scales. Further analysis on weekly data led to an empirical model describing the process of sediment transport at various spatial scales. The model revealed that drain channels at larger spatial scales (i.e. downstream channels) tended to be dominated by weekly net deposition, while those at smaller spatial scales (i.e. upstream channels) were controlled by weekly net erosion. However, analysis of the 5-min data showed that in small-scale drain channels, large amount of sediment was indeed deposited over a short period of one week (about one day). In the rest of the week, low-intensity erosion prevailed. Therefore, sediment transport in the study watershed was generally controlled by deposition, which supports the necessity of on-going drain-channel dredging by Imperial Irrigation District.