SOIL LIMING AND MINERAL FERTILIZATION FOR ROOT NODULATION AND GROWTH OF FABA BEANS IN AN ACID SOIL IN TUNISIA

Faba beans (Vicia faba L) are grown in northern Tunisia where annual rainfall approaches 1200 mm and where the soil acidity is the most limiting factor for plant growth. Aluminum (Al) and manganese (Mn) toxicities provide a hostile environment to root growth. To alleviate such a problem, farmers use selected acid-tolerant species. However, crop yields remain far below their optimal levels. Liming, a practice to eliminate acidity, has never been tried in this area before. This research aimed to evaluate the impact of lime and mineral fertilizers on root nodulation, plant uptake and yield of faba beans using a pot experiment. Treatments were combinations of two rates of calcium carbonate with three rates of superphosphate and three rates of potassium sulfate. Liming produced significantly higher number and weight of nodules on roots as well as higher nitrogen, phosphorus, and potassium contents in plant tissue. Liming also increased shoot growth and bean yield.     

Disease and injury among participants in the Agricultural Health Study

The Agricultural Health Study (www.aghealth.org) is a cohort of 89,658 pesticide applicators and their spouses from Iowa and North Carolina assembled between 1993 and 1997 to evaluate riskfactorsfor disease in ruralfarm populations. This prospective study is just now reaching sufficient maturity for analysis of many disease endpoints. Nonetheless, several analyses have already provided interesting and important leads regarding disease patterns in agricultural populations and etiologic clues for the general population. Compared to the mortality experience of the general population in the two states (adjusted for race, gender, age and calendar time), the cohort experienced a very low mortality rate overall and for many specific causes and a low rate of overall cancer incidence. A few cancers, however, appear elevated, including multiple myeloma and cancers of the lip, gallbladder, ovary, prostate, and thyroid, but numbers are small for many cancers. A study of prostate cancer found associations with exposure to several pesticides, particularly among individuals with a family history of prostate cancer. Links to pesticides and other agricultural factors have been found for injuries, retinal degeneration, and respiratory wheeze. Methodological studies have determined that information collected by interview is unbiased and reliable. A third round of interviews scheduled to begin in 2005 will collect additional information on agricultural exposures and health outcomes. The study can provide data to address many health issues in the agricultural community. The study investigators welcome collaboration with interested scientists.     

A thymic precursor to the NK T cell lineage

CD1d-restricted autoreactive natural killer (NK1.1+) T cells function as regulatory cells in various disease conditions. Using improved tetramer tracking methodology, we identified a NK1.1- thymic precursor and followed its differentiation and emigration to tissues by direct cell transfer and in situ cell labeling studies. A major lineage expansion occurred within the thymus after positive selection and before NK receptor expression. Surprisingly, cytokine analysis of the developmental intermediates between NK and NK+ stages showed a T helper cell TH2 to TH1 conversion, suggesting that the regulatory functions of NK T cells may be developmentally controlled. These findings characterize novel thymic and postthymic developmental pathways that expand autoreactive cells and differentiate them into regulatory cells.     

Eulachnus tuberculostemmatus (Lachninae: Eulachnini) sur pin d'Alep: premier signalement en Tunisie

During a study on the population dynamics of aphids on Aleppo pine, Pinus halepensis, in Chott Mariem region, Eulachnus tuberculostemmatus Theobald was found. This is the first record of the species in Tunisia.     

Composition and insecticidal activity of essential oil from Ruta graveolens,Mentha pulegium and Ocimum basilicum against Ectomyelois ceratoniae Zeller and Ephestia kuehniella Zeller (Lepidoptera: Pyralidae)

Journal of Plant Diseases and Protection - The aim of this research was to explore the chemical composition and evaluate the insecticidal activities of Ruta graveolens, Mentha pulegium and Ocimum...     

Lotusine G: a new cyclopeptide alkaloid from Zizyphus lotus

In addition to six cyclopeptide alkaloids lotusines A-F, a new compound lotusine G, was isolated from the root bark of Zizyphus lotus by centrifugal partition chromatography.     

Sesquiterpene lactones from Centaurea musimomum. Antiplasmodial and cytotoxic activities

The chloroform extract of the aerial parts of Centaurea musimomum exhibited significant activity against Plasmodium falciparum. The phytochemical study of this extract gave seven native and four acetylated sesquiterpene lactones.     

Role of Ammonium to Limit Nitrate Accumulation and to Increase Water Economy in Wild Swiss Chard

ABSTRACT

The present study was performed to characterize the interaction between nitrogen (N) form and availability with respect to growth, water relations, and mineral nutrition of wild swiss chard (Beta macrocarpa Guss). Plants were cultured hydroponically with two levels of N concentrations, high-N (2.5 mM) or low-N (0.5 mM), added as nitrate (NO^? ₃) or ammonium (NH⁺ ₄). At high N, growth was affected significantly by N form. If the NO^? ₃ medium was considered as control, the use of NH⁺ ₄ decreased dry matter production and leaf area by ca. 35%. Use of NH⁺ ₄ led to water economy and did not affect the nutrient content of the plant tissues. Compared to growth with high N, plants growth fell in either low- NO^? ₃ or low- NH⁺ ₄ medium. In this case, the difference between the two N sources was not significant. Our results showed that the replacement of NO^? ₃ by NH⁺ ₄ as the N source decreased the NO^? ₃ concentration in consumable leaves and increased the water use efficiency.