Hichem H.,Institute National Of Recherche En Genie Rural |
El Naceur A.,University of Monastir |
Mounir D.,Institute Superieur Agronomique Of Chott Mariem
Photosynthetica | Year: 2010
The effect of four different NaCl concentrations (from 0 to 102 mM NaCl) on seedlings leaves of two corn (Zea mays L.) varieties (Aristo and Arper) was investigated through chlorophyll (Chl) a fluorescence parameters, photosynthesis, stomatal conductance, photosynthetic pigments concentration, tissue hydration and ionic accumulation. Salinity treatments showed a decrease in maximal efficiency of PSII photochemistry (F v/F m) in dark-adapted leaves. Moreover, the actual PSII efficiency (φ PSII), photochemical quenching coefficient (q p), proportion of PSII centers effectively reoxidized, and the fraction of light used in PSII photochemistry (%P) were also dropped with increasing salinity in light-adapted leaves. Reductions in these parameters were greater in Aristo than in Arper. The tissue hydration decreased in salt-treated leaves as did the photosynthesis, stomatal conductance (g s) and photosynthetic pigments concentration essentially at 68 and 102 mM NaCl. In both varieties the reduction of photosynthesis was mainly due to stomatal closure and partially to PSII photoinhibition. The differences between the two varieties indicate that Aristo was more susceptible to salt-stress damage than Arper which revealed a moderate regulation of the leaf ionic accumulation. © Springer Science+Business Media B.V. 2010.
Hajlaoui H.,Institute National Of Recherche En Genie Rural |
Ayeb N.E.,University of Monastir |
Garrec J.P.,French National Institute for Agricultural Research |
Denden M.,Institute Superieur Agronomique Of Chott Mariem
Industrial Crops and Products | Year: 2010
The comparative effects of salt stress on osmotic adjustment and solutes accumulation in relation to root-leaf tissue senescence of two silage maize varieties were examined. Studies were carried out with seedlings of two forage maize varieties (Aristo and Arper) subjected to 0, 34, 68 and 102 mM NaCl for 6 weeks under glasshouse conditions. Osmotic potential (OP), osmotic adjustment (OA) and solutes accumulation were quantified in primary roots and in three leaf stages (young, mature and senescent leaves). Moreover, in order to assess the distribution of proline and glycine betaine during root development, the two components were analyzed at different position from the primary root apex of both varieties. The total dry matter was significantly dropped with increasing salinity and reduction was greater in Aristo than in Arper. Salt stress impact in terms of ionic status was more pronounced in roots than in leaves and in older leaves than younger ones. In this setting, Aristo displayed a more sensitivity than Arper. A close relationship between the age of root-leaf tissue and proline and glycine betaine allocation, as salinity response, was shown. During the stress treatment, the accumulation of the two components was higher in growing regions of roots and in young leaves. While total free amino acids (FAA) and sugars were accumulated in roots as well as leaves but preferentially in the mature leaves. The capacity of OA was greater in young than in mature and/or senescent leaves and the contribution efficiency of organic solutes to this occurrence tended to be higher in Arper than in Aristo. Moreover, glycine betaine and proline appeared to be the main solutes that contributed ably to OA mainly in growing regions followed by sugars and other FAA. Inorganic solutes (K+ and Ca2+), however, did not seem to play an important role in OA since their amounts were often reduced in response to salt tolerance. © 2009 Elsevier B.V. All rights reserved.
Fenet H.,Montpellier University |
Mathieu O.,CHRU de Montpellier |
Mahjoub O.,Institute National Of Recherche En Genie Rural |
Li Z.,Montpellier University |
And 3 more authors.
Chemosphere | Year: 2012
Treated wastewater is being increasingly used for irrigation and aquifer replenishment through artificial recharge. However, wastewater reuse can result in contamination of exposed soil and groundwater by chemicals such as some pharmaceuticals and their metabolites. The fate of these molecules depends largely on their capacity to sorb onto soil and aquifer materials during infiltration. In this study, the sorption isotherm of carbamazepine (CBZ), an anti-seizure medication, and two of its metabolites, i.e. carbamazepine-10,11-epoxide (CBZ-EP) and 10,11-dihydro-10,11-dihydroxycarbamazepine (DiOH-CBZ), were determined in two soils in laboratory assays. In the field, the presence of CBZ and its metabolites were investigated in soil and in groundwater underlying an irrigated area with treated wastewater. The results showed that CBZ had the highest carbon normalised sorption coefficients in the two tested soils (irrigated soil and a Lufa SP2.4 reference soil) followed by CBZ-EP and DiOH-CBZ, indicating the relatively higher mobility of CBZ metabolites compared to CBZ. The chromatographic analysis revealed that CBZ and its two metabolites were present in treated wastewater used for irrigation and in groundwater. In soil samples, CBZ concentrations showed a build-up taking place with irrigation. The mobility of metabolites in soil and their potential biodegradation require further investigation. © 2012 Elsevier Ltd.
Iglesias A.,Technical University of Madrid |
Mougou R.,Institute National Of Recherche En Genie Rural |
Moneo M.,Potsdam Institute for Climate Impact Research |
Quiroga S.,University of Alcala
Regional Environmental Change | Year: 2011
This study links climate change impacts to the development of adaptation strategies for agriculture on the Mediterranean region. Climate change is expected to intensify the existing risks, particularly in regions with current water scarcity, and create new opportunities for improving land and water management. These risks and opportunities are characterised and interpreted across Mediterranean areas by analysing water scarcity pressures and potential impacts on crop productivity over the next decades. The need to respond to these risks and opportunities is addressed by evaluating an adaptive capacity index that represents the ability of Mediterranean agriculture to respond to climate change. We propose an adaptive capacity index with three major components that characterise the economic capacity, human and civic resources, and agricultural innovation. These results aim to assist stakeholders as they take up the adaptation challenge and develop measures to reduce the vulnerability of the sector to climate change. © 2010 The Author(s).
Boughalleb F.,Institute Superieur Agronomique Of Chott Meriem Isa Cm |
Hajlaoui H.,Institute National Of Recherche En Genie Rural
Acta Physiologiae Plantarum | Year: 2011
Photosynthetic gas exchange, vegetative growth, water relations and fluorescence parameters as well as leaf anatomical characteristics were investigated on young plants of two Olea europaea L. cultivars (Chemlali and Zalmati), submitted to contrasting water availability regimes. Two-year-old olive trees, grown in pots in greenhouse, were not watered for 2 months. Relative growth rate (RGR), leaf water potential (ΨLW) and the leaf relative water content (LWC) of the two cultivars decreased with increasing water stress. Zalmati showed higher values of RGR and LWC and lower decreased values of ΨLW than Chemlali, in response to water deficit, particularly during severe drought stress. Water stress also caused a marked decline on photosynthetic capacity and chlorophyll fluorescence. The net photosynthetic rate, stomatal conductance, transpiration rate, the maximal photochemical efficiency of PSII (Fv/Fm) and the intrinsic efficiency of open PSII reaction centres (F′v/F′m) decreased as drought stress developed. In addition, drought conditions, reduced leaf chlorophyll and carotenoids contents especially at severe water stress. However, Zalmati plants were the less affected when compared with Chemlali. In both cultivars, stomatal control was the major factor affecting photosynthesis under moderate drought stress. At severe drought-stress levels, the non-stomatal component of photosynthesis is inhibited and inactivation of the photosystem II occurs. Leaf anatomical parameters show that drought stress resulted in an increase of the upper epidermis and palisade mesophyll thickness as well as an increase of the stomata and trichomes density. These changes were more characteristic in cv. 'Zalmati'. Zalmati leaves also revealed lower specific leaf area and had higher density of foliar tissue. From the behaviour of Zalmati plants, with a smaller reduction in relative growth rate, net assimilation rate and chlorophyll fluorescence parameters, and with a thicker palisade parenchyma, and a higher stomatal and trichome density, we consider this cultivar more drought-tolerant than cv. Chemlali and therefore, very promising for cultivation in arid areas. © 2010 Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków.