Diversité spécifique végétale dans un important écosystème des Émirats Arabes Unis

The aim of the present study was to assess the effect of protection from grazing on species diversity in Wadi Tarabat protected area, Al Ain, United Arab Emirates. This study was conducted during spring and summer to identify the species diversity using Shannon-Wiener, Brillouin and Simpson species diversity indices in addition to the importance value (IV). A total of 106 different species was recorded. Shannon-Wiener index was significantly higher in the protected area in comparison to the unprotected one (2.64 and 2.15; respectively) and during spring than summer seasons (2.50 and 2.28; respectively). The Simpson index did only reveal significant protection effect (P < 0.001). Shannon-Wiener and Brillouin indices are suggested to be more appropriate to express diversity in the study sites. Acacia tortilis, Cenchrus ciliaris and Pennisetum divisum had the highest IV in both protected and unprotected areas during spring and summer. The IV values for A. tortilis ranged between 38.9%, in protected areas during spring, to 44.3% in unprotected areas during summerLe but de la présente étude est d'évaluer l'effet de la protection contre le pâturage sur la diversité des espèces dans la zone protégée de Wadi Tarabat, Al Ain, Émirats Arabes Unis. Cette étude a été menée au printemps et en été afin d'identifier la diversité des espèces à l'aide des indices de Shannon-Wiener, Brillouin et Simpson, ainsi que la valeur d'importance (I.V.). Un total de 106 espèces différentes a été enregistré. L'indice de Shannon-Wiener s'est avéré plus élevé en zone protégée qu'en zone non protégée (2,64 et 2,15; respectivement) et au printemps plus qu'en été (2,50 et 2,28; respectivement). L'indice de Simpson n'a fait que révéler l'effet de la protection (P < 0,001). Les indices de Shannon-Wiener et de Brillouin sont préconisés comme les plus appropriés pour exprimer la diversité dans les sites d'étude. Acacia tortilis, Cenchrus ciliaris et Pennisetum divisum avaient la plus forte I.V. tant dans les zones protégées que non protégées au cours du printemps et en été. Les I.V. pour A. tortilis variaient entre 38,9%, dans des zones protégées au cours du printemps, à 44,3% dans les zones non protégées pendant l'été

Distribution of heavy metals in vegetative biofiltration columns

This study investigated the distribution of heavy metals in vegetative biofiltration columns irrigated by synthetic greywater. Twelve species of ornamental plants (three plants from each species) were planted in the same designed 36 biofiltration columns. Samples of effluent water, soils, roots, shoots and leaves were collected and analyzed. It was observed that before irrigation, the distribution of copper was in soils (0%), roots (42%), leaves (37%) and shoots (21%). After irrigation, this distribution changed to soils (29%), roots (39%), leaves (17%) and shoots (15%). It was found that lead concentrations decreased in soils from (84% to 7%), but increased in plants (from 16% to 93%) following irrigation with greywater. In contrast, the distribution of zinc changed from leaves (46%), roots (22%) and soils (16%) before irrigation to 89% in leaves and soils and 11% in shoots following irrigation. The chromium distribution before and after irrigation was found to be almost unchanged in soils, shoots and effluent water, but it increased in roots (19.4% to 26.9%) and decreased in leaves (11.4% to 5.8%). The outcomes of this study demonstrated that heavy metals mostly accumulate in soils and roots, and it is necessary to investigate their potential detrimental effects on the receiving environment

Réponse à la température et à la salinité de la germination des semences d’Allium ampeloprasum en Tunisie

High salinity and temperature are major problems inhibiting seeds germination and threatening plant cover in arid environment such as the conditions in some regions in Tunisia. Thus, the use of adapted species to rehabilitate these regions could be an alternative to overcome these environmental constraints. In the present study, we intended to evaluate the effect of salt and temperature on seed germination of the wild leek (A. ampeloprasum L.) from two different Tunisian islands (Kneiss & Djerba). Three temperatures (15° C, 23° C & 30° C) and four salinity levels (0, 75, 150 & 225 mM NaCl) were tested in a 14 h dark:10 h light photoperiod. The two studied populations showed a similar behaviour. The optimum temperature for seed germination was 15° C. G ermination was inhibited by an increase in both temperature and salinity. Salt stress decreased both the final germination rate and the final germination percentage (PG%). Delay of germination (T0) and the time to half of germination (T50) significantly (p < 0.05) increased in response to salt and temperature increasing. An interaction between salinity and temperature completely inhibited germination in 225 mM NaCl at 30° C. S eeds transferred from salt solution to distilled water showed a recovery percentage (R%) varying from 0 to 40.6 %. Viability test showed that all non-germinated seeds were alive proving that A. ampeloprasum adopted a strategy of temporal inhibition of germination to survive under salt and temperatures increasing. As such it could be classified as a moderately salt tolerant speciesLa salinité et les températures élevées sont les principaux problèmes inhibant la germination des semences et menaçant le couvert végétal dans les environnements arides comme c'est lc cas dans certaines régions de Tunisie. Ainsi, pour réhabiliter ces régions, des espèces adaptées peuvent être utilisées pour contourner ces contraintes environnementales. Dans la présente étude, on a évalué l'effet du sel et de la température sur la germination des semences d'Allium ampeloprasum de deux îles tunisiennes (Kneiss & Djerba). Trois températures (15° C, 23° C & 30° C) et quatre niveaux de salinité (0, 75, 150 & 225 mM NaCl) ont été testés à une photopériode de 10 h. Les deux populations étudiées ont montré des comportements similaires. L'optimum thermique pour la germination a été de 15° C. La germination a été inhibée par une augmentation de température et de salinité. Le sel a diminué le taux de germination finale et le pourcentage de germination (PG%). Le délai de germination (To) et le temps pour 50 % de germination (T50) ont augmenté significativement en réponse à une augmentation de la température et de la salinité. Une interaction entre la salinité et la température a complètement inhibé la germination à 30° C avec 225 mM NaCl. Les semences transférées à l'eau distillée ont montré un pourcentage de recouvrement variant de 0 à 40,6 %. Le test de viabilité a montré que toutes les semences non germées étaient viables, prouvant ainsi que A. ampeloprasum adopte une stratégie d'inhibition temporaire de germination pour survivre à des hautes températures et salinités. A. ampeloprasum peut être classifié comme une espèce modérément tolérante

Antioxidant, Lipoxygenase and Histone Deacetylase Inhibitory Activities of Acridocarpus orientalis From Al Ain and Oman

Acridocarpus orientalis (AO) is a traditional medicinal plant used for treatment of inflammatory diseases that may have potential in cancer treatment. In the present study, the aqueous ethanolic crude extract of Acridocarpus aerial parts obtained from Al Ain and Oman were evaluated for their antioxidant capability, polyphenolic content, anti-lipoxygenase and anti-histone deacetylase (HDAC) properties. The total antioxidant capacity was estimated by the FRAP, DPPH, ABTS and b-carotene bleaching assays. Acridocarpus-Al Ain exhibited the highest polyphenolic content (184.24 mg gallic acid/g) and the best antioxidant activity (1.1, 1.04, 1.14 mmol ascorbic acid equivalent/g in the FRAP, ABTS and DPPH assays, respectively). Additionally, the same extract showed significant anti-inflammatory properties via lipoxygenase (LOX) inhibitory activity (IC50 = 50.58 µg/mL). Acridocarpus-Al Ain also showed the strongest histone deacetylase (HDACs) inhibitory activity (IC50 = 93.28 µg/mL). The results reported here suggest that there was a significant influence of location and the plant may be considered a good source of compounds with antioxidant, anti-LOX and HDAC properties for therapeutic, nutraceutical and functional food applications

Plant species diversity within an important United Arab Emirates ecosystem

The aim of the present study was to assess the effect of protection from grazing on species diversity in Wadi Tarabat protected area, Al Ain, United Arab Emirates. This study was conducted during spring and summer to identify the species diversity using Shannon-Wiener, Brillouin and Simpson species diversity indices in addition to the importance value (IV). A total of 106 different species was recorded. Shannon-Wiener index was significantly higher in the protected area in comparison to the unprotected one (2.64 and 2.15 ; respectively) and during spring than summer seasons (2.50 and 2.28 ; respectively). The Simpson index did only reveal significant protection effect (P< 0.001). Shannon-Wiener and Brillouin indices are suggested to be more appropriate to express diversity in the study sites. Acacia tortilis, Cenchrus ciliaris and Pennisetum divisum had the highest IV in both protected and unprotected areas during spring and summer. The IV values for A. tortilis ranged between 38.9%, in protected areas during spring, to 44.3% in unprotected areas during summer.Diversité spécifique végétale dans un important écosystème des Émirats Arabes Unis. Le but de la présente étude est d’évaluer l’effet de la protection contre le pâturage sur la diversité des espèces dans la zone protégée de Wadi Tarabat, Al Ain, Émirats Arabes Unis. Cette étude a été menée au printemps et en été afin d’identifier la diversité des espèces à l’aide des indices de Shannon-Wiener, Brillouin et Simpson, ainsi que la valeur d’importance (I. V.). Un total de 106 espèces différentes a été enregistré. L’indice de Shannon-Wiener s’est avéré plus élevé en zone protégée qu’en zone non protégée (2,64 et 2,15 ; respectivement) et au printemps plus qu’en été (2,50 et 2,28 ; respectivement). L’indice de Simpson n’a fait que révéler l’effet de la protection (P < 0,001). Les indices de Shannon-Wiener et de Brillouin sont préconisés comme les plus appropriés pour exprimer la diversité dans les sites d’étude. Acacia tortilis, Cenchrus ciliaris et Pennisetum divisum avaient la plus forte I. V. tant dans les zones protégées que non protégées au cours du printemps et en été. Les I. V. pour A. tortilis variaient entre 38,9%, dans des zones protégées au cours du printemps, à 44,3% dans les zones non protégées pendant l’été.Mohamed Fawzi Nael, Ksiksi Taoufik. Plant species diversity within an important United Arab Emirates ecosystem. In: Revue d'Écologie (La Terre et La Vie), tome 68, n°1, 2013. pp. 25-36

Up in the Air: How might global warming and the greenhouse effect impact rangelands?

The Rangelands archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform March 202

Mechanical scarification: The key to optimal germination parameters in nine flowering species of the United Arab Emirates

Seed germination is the most essential stage of the plant life. Prior to germination, seed dormancy provides protection to the seed against germinating under unfavorable conditions. The seeds of many plants in arid regions are particularly characterized by having a hard seed coat. Seed dormancy is essential to the survival of plants, however in some incidents such as reforestation on desert areas, it is important for ecologists to investigate methods of breaking the dormancy of seeds in order to maximize the production of plants. In this study, we tested four methods of seed pre-treatment (Mechanical scarification (MChip), chemical scarification with sulfuric acid at two exposure durations (SAcid15, SAcid30), and soaking in water for 24 h (Soak)) on 9 flowering plants (Senna italica, Sorghum sudanense, Tephrosia nubica, Senna angustifolia, Acacia tortilis, Senna occidentalis, Abutilon pannosum, Prosopis cineraria, Crotalaria persica) of the UAE. Six germination parameters (Final germination percentage (G) %, Mean germination time (MGT) day, Mean germination rate (MGR) day, Coefficient of velocity of germination (CVG) %, Mean Daily Germination Percentage (MDG) %, and Germination index (GI) day) were calculated to assess the germination. Final Germination Percentage (G) significantly improved (P < 0.005) in seven species (100% in S. italica, 98% in S. sudanense, 97% in T. nubica, 99% in S. angustifolia, 98% in A. tortilis, 99% in P. cineraria, and 93% in C. persica) with Mchip and SAcid30 (1.124% in S. italica, 28% in S. sudanense, 3% in T. nubica,82% in S. angustifolia, 96% in A. tortilis, 99% in P. cineraria, and 25% in C. persica), three species (1.562% in S. italica, 28% in S. sudanense, 3% in T. nubica, 62% in S. angustifolia, and 62% in P. cineraria) with (SAcid15), and only two species (3% in T. nubica and 5% in A. tortilis) with Soak. S. occidentalis was the only species that did not show significant changes in germination parameters after each treatment. Mechanical scarification is the safest and most affective pretreatment method according to our findings

Mechanical scarification: The key to optimal germination parameters in nine flowering species of the United Arab Emirates

Seed germination is the most essential stage of the plant life. Prior to germination, seed dormancy provides protection to the seed against germinating under unfavorable conditions. The seeds of many plants in arid regions are particularly characterized by having a hard seed coat. Seed dormancy is essential to the survival of plants, however in some incidents such as reforestation on desert areas, it is important for ecologists to investigate methods of breaking the dormancy of seeds in order to maximize the production of plants. In this study, we tested four methods of seed pre-treatment (Mechanical scarification (MChip), chemical scarification with sulfuric acid at two exposure durations (SAcid15, SAcid30), and soaking in water for 24 h (Soak)) on 9 flowering plants (Senna italica, Sorghum sudanense, Tephrosia nubica, Senna angustifolia, Acacia tortilis, Senna occidentalis, Abutilon pannosum, Prosopis cineraria, Crotalaria persica) of the UAE. Six germination parameters (Final germination percentage (G) %, Mean germination time (MGT) day, Mean germination rate (MGR) day, Coefficient of velocity of germination (CVG) %, Mean Daily Germination Percentage (MDG) %, and Germination index (GI) day) were calculated to assess the germination. Final Germination Percentage (G) significantly improved (P < 0.005) in seven species (100% in S. italica, 98% in S. sudanense, 97% in T. nubica, 99% in S. angustifolia, 98% in A. tortilis, 99% in P. cineraria, and 93% in C. persica) with Mchip and SAcid30 (1.124% in S. italica, 28% in S. sudanense, 3% in T. nubica,82% in S. angustifolia, 96% in A. tortilis, 99% in P. cineraria, and 25% in C. persica), three species (1.562% in S. italica, 28% in S. sudanense, 3% in T. nubica, 62% in S. angustifolia, and 62% in P. cineraria) with (SAcid15), and only two species (3% in T. nubica and 5% in A. tortilis) with Soak. S. occidentalis was the only species that did not show significant changes in germination parameters after each treatment. Mechanical scarification is the safest and most affective pretreatment method according to our findings

Performance of vegetative bioretention system for greywater reuse in the arid climates

Water Sensitive Urban Design (WSUD) technologies are acknowledged to play a significant role in improving the quality of stormwater in the urban landscape. However, findings have shown that greywater, the residential wastewater except that originates from toilet and kitchen, could be used to operate the vegetative bioretention system in the arid climates. A positive signal was received when investigated in the laboratory settings, however, a better picture and a more representative result can be obtained if the system is studied in a field scale. The study intended to explore further, the effectiveness of using the vegetative bioretention to treat urban greywater. This WSUD system can play a dual role in improving greywater quality and landscape aesthetics. Selection of appropriate plants for them is also an important research question. Twelve different species of native and exotic plants in triplet planted in 36 prototype bioretention columns in the laboratory. The columns were irrigated by synthetic greywater and the removal efficiency of heavy metals and other common water quality parameters were monitored on a regular basis. The retention of heavy metals in the water, plants leaves, stem and roots) and soil were also investigated. It was found that the Pennisetum seateceum provides more consistency and efficiency in removing heavy metals from greywater

Response of seed germination of Tunisian Allium ampeloprasum to temperature and salt stresses

High salinity and temperature are major problems inhibiting seeds germination and threatening plant cover in arid environment such as the conditions in some regions in Tunisia. Thus, the use of adapted species to rehabilitate these regions could be an alternative to overcome these environmental constraints. In the present study, we intended to evaluate the effect of salt and temperature on seed germination of the wild leek (A. ampeloprasum L.) from two different Tunisian islands (Kneiss & Djerba). Three temperatures (15° C, 23° C & 30° C) and four salinity levels (0, 75, 150 & 225 mM NaCl) were tested in a 14 h dark : 10 h light photoperiod. The two studied populations showed a similar behaviour. The optimum temperature for seed germination was 15° C. Germination was inhibited by an increase in both temperature and salinity. Salt stress decreased both the final germination rate and the final germination percentage (PG%). Delay of germination (T0) and the time to half of germination (T50) significantly (p < 0.05) increased in response to salt and temperature increasing. An interaction between salinity and temperature completely inhibited germination in 225 mM NaCl at 30° C. Seeds transferred from salt solution to distilled water showed a recovery percentage (R%) varying from 0 to 40.6 %. Viability test showed that all non-germinated seeds were alive proving that A. ampeloprasum adopted a strategy of temporal inhibition of germination to survive under salt and temperatures increasing. As such it could be classified as a moderately salt tolerant species.Réponse à la température et à la salinité de la germination des semences d’Allium ampeloprasum en Tunisie. La salinité et les températures élevées sont les principaux problèmes inhibant la germination des semences et menaçant le couvert végétal dans les environnements arides comme c’est le cas dans certaines régions de Tunisie. Ainsi, pour réhabiliter ces régions, des espèces adaptées peuvent être utilisées pour contourner ces contraintes environnementales. Dans la présente étude, on a évalué l’effet du sel et de la température sur la germination des semences d’Allium ampeloprasum de deux îles tunisiennes (Kneiss & Djerba). Trois températures (15° C, 23° C & 30° C) et quatre niveaux de salinité (0, 75, 150 & 225 mM NaCl) ont été testés à une photopériode de 10 h. Les deux populations étudiées ont montré des comportements similaires. L’optimum thermique pour la germination a été de 15° C. La germination a été inhibée par une augmentation de température et de salinité. Le sel a diminué le taux de germination finale et le pourcentage de germination (PG%). Le délai de germination (T0) et le temps pour 50 % de germination (T50) ont augmenté significativement en réponse à une augmentation de la température et de la salinité. Une interaction entre la salinité et la température a complètement inhibé la germination à 30° C avec 225 mM NaCl. Les semences transférées à l’eau distillée ont montré un pourcentage de recouvrement variant de 0 à 40,6 %. Le test de viabilité a montré que toutes les semences non germées étaient viables, prouvant ainsi que A. ampeloprasum adopte une stratégie d’inhibition temporaire de germination pour survivre à des hautes températures et salinités. A. ampeloprasum peut être classifié comme une espèce modérément tolérante.Guenaoui Chedia, Ksiksi Taoufik Saleh, Aschi-Smiti Samira, Neffati Mohamed. Response of seed germination of Tunisian Allium ampeloprasum to temperature and salt stresses. In: Revue d'Écologie (La Terre et La Vie), tome 67, n°4, 2012. pp. 399-408