Responses of Batis maritima plants challenged with up to two‐fold seawater NaCl salinity

Batis maritima is a promising halophyte for sand‐dune stabilization and saline‐soil reclamation. This species has also applications in herbal medicine and as an oilseed crop. Here, we address the plant response to salinity reaching up to two‐fold seawater concentration (0–1000 mM NaCl), with a particular emphasis on growth, water status, mineral nutrition, proline content, and photosystem II integrity. Plant biomass production was maximal at 200 mM NaCl, and the plants survived even when challenged with 1000 mM NaCl. Plant water status was not impaired by the high accumulation of sodium in shoots, suggesting that Na⁺ compartmentalization efficiently took place in vacuoles. Concentrations of Mg²⁺ and K⁺ in shoots were markedly lower in salt‐treated plants, while that of Ca²⁺ was less affected. Soluble‐sugar and chlorophyll concentrations were hardly affected by salinity, whereas proline concentration increased significantly in shoots of salt‐treated plants. Maximum quantum efficiency (F_v/F_m), quantum yield of PSII (Φ_PSII), and electron‐transport rate (ETR) were maximal at 200–300 mM NaCl. Both nonphotochemical quenching (NPQ) and photochemical quenching (qP) were salt‐independent. Interestingly, transferring the plants previously challenged with supraoptimal salinities (400–1000 mM NaCl) to the optimal salinity (200 mM NaCl) substantially restored their growth activity. Altogether, our results indicate that B. maritima is an obligate halophyte, requiring high salt concentrations for optimal growth, and surviving long‐term extreme salinity. Such a performance could be ascribed to the plant capability to use sodium for osmotic adjustment, selective absorption of K⁺ over Na⁺ in concomitance with the stability of PSII functioning, and the absence of photosynthetic pigment degradation.     

Nutrient Stress,Ecophysiological, and Metabolic Aspects of Olive Tree Cultivars

This research, aimed at evaluating stress on the olive tree, utilized cultivars ‘Meski’ and ‘Chetoui’ in regards to the removal of major elements such as nitrogen (N), phosphorus (P), magnesium (Mg), and potassium (K). The experiment was conducted under greenhouse conditions in hydroponics culture. Measurements of leaf area showed a non-substantial and weak effect due to phosphorus, potassium, or magnesium deficiency compared to nitrogen. The growth analysis of dry matter showed an early depressive effect of nitrogen deficiency and a similar, but less important effect concerning phosphorus.

The induced nutritional stresses showed an important increase in stomata resistance, caused primarily by nitrogen or potassium deficiency, accompanied by a reduction of chlorophyll concentration, which resulted from the removal of phosphorus, magnesium, and mainly nitrogen supply. Remarkable starch synthesis and storage was also revealed following nitrogen deficiency, but it was very weak after the suppression of magnesium, which may provoke a weakening of growth and development of these plants.     

Histopathological effects of Bacillus subtilis SPB1 biosurfactant in the midgut of Ephestia kuehniella (Lepidoptera: Pyralidae) and improvement of its insecticidal efficiency

Journal of Plant Diseases and Protection - The present investigation aimed to throw light on the effect of Bacillus subtilis SPB1 biosurfactant on the third larval instars of the Mediterranean...     

Monitoring: Physic‐Chemical,Microbiological, and Phytotoxic Parameters of Mixed Oil Mill Waste and Green Waste Composts Moistened with Treated Urban Wastewater and Tap Water

In Tunisia, on‐site co‐composting of oil mill waste would overcome environmental issues and valorize renewable resources. The authors' goal was to determine the physic‐chemical and microbiological properties and nutrient supply characteristics of mixed oil mill waste and green waste compost. Two piles of the same raw materials (2/3 oil mill waste–1/3 green waste, w/w) were moistened with two kinds of water: treated urban wastewater (A₁) and tap water (A₂). Results showed the following: (i) produced compost decreased in C/N from 32 to 12.30?±?0.89 (A₁) and 11?±?0.89 (A₂); (ii) major elements (P and K) were within acceptable limits; (iii) A₁ and A₂ had potentially lower heavy metal contents than the limits established by the second draft of the Biological Treatment of Biowaste of the European Commission and microbial load values below the limit N FU 44‐051 values; (iv) A₁ and A₂ had, respectively, 93 and 89.67% as germination index Gl values, which confirmed the composts' maturity and safety; (v) for both composts, A₁ and A₂, culture potting made up of half compost and half soil revealed the highest bean leaves' number; and (vi) the less richness in minerals and organic compounds of A₂ compared to A₁ gave better germination results for white wheat and bean leaves' number for A₂. Even moistened with treated urban waste water, oil mill wastes proved to be very interesting for co‐composting with green waste.     

Characterization of virgin olive oil from Super Intensive Spanish and Greek varieties grown in northern Tunisia

The aim of this study was to evaluate minor components (phenolic compounds, α-tocopherols and pigments), fatty acid contents and oxidative stability of virgin olive oil of Spanish cultivars: Arbequina, Arbequina I-18 and Arbosana and Greek cultivar: Koroneiki grown in Northern Tunisia under irrigated high-density plantation system. Thus, in order to have better knowledge about the quali-quantitative profiles of these components in samples obtained from the same collecting seasons and the same processing techniques. Fourteen phenolic compounds were detected and quantified by SPE RP-HPLC. Dialdehydic form of elenolic acid linked to tyrosol and hydroxytyrosol, oleuropein and ligstroside aglycones were the main components in all samples. Pinoresinol was the most abundant component in lignan fraction. These phenolic compounds, α-tocopherols, total phenols and o-diphenols showed significant correlations with oxidative stability. Furthermore, the majority of the studied analytical parameters were greatly influenced by the cultivar–environment interaction. In fact, significant differences between the studied oils were detected.