Contributions of indigenous arbuscular mycorrhizal fungi to growth of retama monosperma and acacia gummifera under water stress (case study: essaouira sand dunes forest)     

Abdessamad Fakhech  Najat Manaut  Lahcen Ouahmane  Mohamed Hafidi 《Journal of Sustainable Forestry》2019,38(7):686-696

ABSTRACT

Two leguminous plant species: Retama monosperma and Acacia gummifera were selected for water deficit tolerance test for future use in reforestation programs of the Atlantic sand dunes forest of Essaouira region. Mycorrhizal fungal colonization was used to help plants amend the water deficit. To assess R. monosperma and A. gummifera response to water stress and the effectiveness of mycorrhizal formation alleviating it, two categories for each plant species were made, one inoculated with mycorrhizal fungi and the other not, were submitted to a hydric deficit treatment of four levels for 6 months. This treatment impact on the plants was assessed by comparing root/shoot dry weight ratios, levels of nitrogen and phosphorus, and by measuring mycorrhizal colonization frequencies and intensities. Results showed that these parameters were significantly affected by water deficit. The presence of the mycorrhizal fungi had significantly enhanced plants phosphorus uptake by 72–124% for Acacia gummifera and 87–161% for Retama monosperma. Nitrogen uptake was increased by 134–388% for Retama monosperma and 510–901% for Acacia gummifera. The colonization frequencies changed significantly only for the treatment extreme level and stayed between 80%-90% for the other levels. The mycorrhization intensities showed significant lessening between each treatment level decreasing from 35% to 10%.  相似文献   

Ophiostoma tsotsi and Ophiostoma quercus associated with Platypus cylindrus F. (Coleoptera: Curculionidae) in cork oak stands in Tunisia     

Amani Bellahirech  Maria L. Incio  Steve Woodward  Mohamed L. Ben Jama  Filomena Nbrega 《Forest Pathology》2019,49(1)

Ambrosia beetles, including Platypus cylindrus, commonly act as vectors of Ophiostomatales. In an investigation of fungi associated with P. cylindrus, several species of Ophiostomatales were identified, including two species of Ophiostoma s. str. These two species were characterized based on comparisons of DNA sequences of the internal transcribed spacer regions including the 5.8S gene of rDNA and β‐tubulin gene. Two distinct clades were discernable in the phylogenetic trees, supported by high bootstrap values. One clade included the species Ophiostoma tsotsi, reported herein for the first time in Tunisia, and the species Ophiostoma quercus.  相似文献   

Pathogenicity of Malaysian Phytophthora palmivora on cocoa,durian, rubber and oil palm determines the threat of bud rot disease     

Intan Nur Ainni Mohamed Azni  Shamala Sundram  Vasagi Ramachandran 《Forest Pathology》2019,49(6)

The epidemic of bud rot disease affecting oil palm in Colombia is primarily caused by Phytophthora palmivora. The pathogen has a cosmopolitan presence that includes Southeast Asia, but to date, bud rot has not been reported in this region. This study provides an overview of the potential risk of Malaysian P. palmivora isolates cross‐infecting other host species, including cocoa, durian, rubber and Malaysian oil palm planting materials (Dura × Pisifera, D × P). On cocoa pods, the durian isolate PP7 caused dark brown necrotic lesions. Detached leaf bioassays showed that P. palmivora isolates PP3 and PP7 infected different hosts, except rubber foliage without wounding. Inoculation tests on cocoa, durian and rubber seedlings caused brown necrotic lesions when stems were wounded, with 10% mortality in cocoa and durian at 17 days post‐inoculation (dpi). However, no further infection was observed, and lesions closed within 14–28 dpi on the non‐wounded seedlings. Pathogenicity tests of oil palm seedlings inoculated with isolates PP3 and PP7 indicated that Malaysian P. palmivora isolates were not pathogenic to oil palms based on localized infection observed only through wounding. Overall, the work demonstrated that Malaysian P. palmivora isolates were able to cross‐infect multiple hosts but did not show severe infections on oil palms.  相似文献   

Bioactive Compounds from Theobroma cacao: Effect of Isolation and Safety Evaluation     

de la Luz Cádiz-Gurrea  María  Fernández de las Nieves  Ignacio  Aguilera Saez  Luis Manuel  Fernández-Arroyo  Salvador  Legeai-Mallet  Laurence  Bouaziz  Mohamed  Segura-Carretero  Antonio 《Plant foods for human nutrition (Dordrecht, Netherlands)》2019,74(1):40-46

Plant Foods for Human Nutrition - Plants, including most food and feed plants, produce a broad range of bioactive chemical compounds. Among these compounds, polyphenols are reported to provide...  相似文献   

Effect of intercropping, Bradyrhizobium inoculation and N, P fertilizers on yields, physical and chemical quality of cowpea seeds     

Ekhlas M. Musa  Elsiddig A. E. Elsheikh  Isam A. Mohamed Ahmed  Elfadil E. Babiker 《Frontiers of Agriculture in China》2011,5(4):543-551

The present study was aimed to determine the effects of inoculation with Bradyrhizobium strain, intercropping, nitrogen and phosphorus fertilization and their interaction on the yield, physical and chemical properties of cowpea seeds. The results showed that the seed yield of cowpea was significantly (P≤0.05) increased by Bradyrhizobium inoculation, nitrogen and phosphorus fertilizers, but not by intercropping. All treatments of intercropping, P, Bradyrhizobium plus N and Bradyrhizobium plus P treatments significantly (P≤0.05) increased the hydration coefficient and cookability of cowpea seeds compared to untreated plants in both seasons. For chemical composition, all treatments significantly (P≤0.05) increased the dry matter, ash, protein and fiber content of the seeds compared to the untreated plants for the two systems and in both seasons, whereas it significantly (P≤0.05) decreased carbohydrate content of the seeds. Fat content of the seeds was not increased by Bradyrhizobium inoculation and intercropping, but it was significantly increased by nitrogen and phosphorus fertilization. Intercropping, Bradyrhizobium inoculation and nitrogen and phosphorus fertilization significantly (P≤0.05) increased tannin content and in vitro protein digestibility of the seeds compared to untreated plants for both systems and in the two seasons.  相似文献   

Bioactive hydroperoxyl cembranoids from the Red Sea soft coral Sarcophyton glaucum     

Hegazy ME  Gamal Eldeen AM  Shahat AA  Abdel-Latif FF  Mohamed TA  Whittlesey BR  Paré PW 《Marine drugs》2012,10(1):209-222

A chemical investigation of an ethyl acetate extract of the Red Sea soft coral Sarcophyton glaucum has led to the isolation of two peroxide diterpenes, 11(S) hydroperoxylsarcoph-12(20)-ene (1), and 12(S)-hydroperoxylsarcoph-10-ene (2), as well as 8-epi-sarcophinone (3). In addition to these three new compounds, two known structures were identified including: ent-sarcophine (4) and sarcophine (5). Structures were elucidated by spectroscopic analysis, with the relative configuration of 1 and 2 confirmed by X-ray diffraction. Isolated compounds were found to be inhibitors of cytochrome P₄₅₀ 1A activity as well as inducers of glutathione S-transferases (GST), quinone reductase (QR), and epoxide hydrolase (mEH) establishing chemo-preventive and tumor anti-initiating activity for these characterized metabolites.  相似文献   

Assessment and mapping of soil erosion risk by water in Tunisia using time series MODIS data     

Mohamed Kefi  Kunihiko Yoshino  Yudi Setiawan 《Paddy and Water Environment》2012,10(1):59-73

Soil erosion by water is a common environmental problem which can affect the sustainable development and the agriculture of developing countries especially. Therefore, several countries, threatened by this phenomenon, adopt different measures to preserve and protect their natural resources. The main purpose of this study was to identify vulnerable areas to establish a soil erosion risk map in Tunisia. In order to do so, an approach based on a combination of the Revised Universal Soil Loss Equation (RUSLE) as an erosion model, Geographic Information System (GIS) and Remote Sensing was applied. RUSLE, which is a model to predict soil loss, is composed of five factors. Erosivity factor (R factor), erodibility factor (K factor), topography factor (LS factor), crop management factor (C factor), and supporting practices factor (P factor). Furthermore, in order to get the most accurate C factor for each land use, times series Moderate Resolution Imaging Spectroradiometer Enhanced Vegetation index (MODIS-EVI) were used. MODIS-EVI time series was helpful for distinguishing vegetation dynamics with taking into account phenological variation of the crops. The results indicated that Tunisia has a serious risk of soil erosion. Indeed, about 24.57% of our study area had a soil loss rate more than 30 t/ha. In these areas, suitable and urgent measures and treatments should be required. Finally, this approach which is based on remote sensing techniques, GIS and erosion model can be useful for planning appropriate environmental decision-making policy in a global scale.  相似文献   

Mosquitocidal activity of two Bacillus bacterial endotoxins combined with plant oils and conventional insecticides     

Sameeh A. Mansour  Mohamed S. FodaAmina R. Aly 《Industrial Crops and Products》2012,35(1):44-52

The full whole culture (FWC), containing parasporal protein toxins of Bacillus thuringiensis israelinsis (Bti) and Bacillus sphaericus 2362 (Bs), either singly or in combination with plant oils and commercial insecticides, was tested against larval and adult stages of Culex pipiens mosquitoes under controlled laboratory conditions. In terms of LC₅₀ values recorded after 24, 48, 72 and 96 h, the bacterial toxins showed high potency towards both larvae and adults of mosquitoes in a dose-dependent manner. Generally, the Bti toxin seemed to be more potent than the Bs toxin. For example, the Bti toxin showed a 24 h LC₅₀ of 8.2 ppm against mosquito larvae compared to 13.6 ppm for the Bs toxin. In the adult bioassay, the obtained 24 h LC₅₀ values were 0.064 and 0.085 mg/cm², respectively for the two bacterial toxins. The bacterial toxins mixed with plant oils or insecticides at equitoxic doses (e.g., LC₂₅ values) mostly showed potentiation effects, either against larvae or adults of the tested insect. Among a total of 14 paired mixtures, only the joint action estimated for the mixture of malathion + Bti or Bs was accounted as additively. Combining Bti or Bs endotoxins at LC₀ with different plant oils and insecticides at LC₅₀ concentration levels each, has resulted in considerable synergism against either larvae or adults. In the case of larval bioassays, the maximum synergistic factor (SF) obtained (ca. 2.0) was entitled to the mixture of Bti + spinosad. In the adult bioassays, the mixtures containing Curcuma longa or Melia azedarach oil extracts with Bti or Bs toxins achieved a SF accounted to 2.0. The results of the present study may be considered as an additional contribution to the area of joint toxicity of biocidal agents combining bacterial toxins, plant oils and traditional insecticides. The reached findings may encourage future research to elucidate its performance under practical field conditions.  相似文献   

Genetic diversity, population structure and relationships of Tunisian Thymus algeriensis Boiss. et Reut. and Thymus capitatus Hoffm. et Link. assessed by isozymes     

Imen Ben El Hadj Ali  Arbi Guetat  Mohamed Boussaid 《Industrial Crops and Products》2012,36(1):149-163

The genetic diversity and population structure of two Tunisian Thymus species (Thymus algeriensis and Thymus capitatus), from 46 natural populations growing in six bioclimates, were analysed by starch gel electrophoresis using eight isozymes. The genetic diversity within populations varied at species level. Variation in T. algeriensis was higher than that observed for T. capitatus, and exclusive alleles were detected for the two studied species. A high differentiation among populations, for each species, estimated by Wright's F-statistics was revealed. In each species, a high level of inbreeding within populations induced by Wahlund effect was observed. A relatively high level of differentiation associated with a restricted gene flow among species was revealed. The PCA and UPGMA analysis, performed on all populations, showed two distinct groups with respect of specific differentiation level. The high genetic divergence between the two species corroborates their taxonomic status, as previously reported using morphological traits. The strategy for the management and conservation of populations should be made for each taxa according to its level of diversity and bioclimate.  相似文献   

Screening of medium components by Plackett-Burman design for carotenoid production using date (Phoenix dactylifera) wastes     

Rafaat M. ElsanhotyI.A. Al-Turki  Mohamed Fawzy Ramadan 《Industrial Crops and Products》2012,36(1):313-320

This work was conducted to use palm date wastes in the production of carotenoids. Three strains of Lactobacillus plantarum (QS1, QS2 and QS3) were isolated from food samples including bakery's yeast, olive fermentation and cheese. Strains were investigated for their structural recA gene by PCR. The recA gene was successfully amplified from all strains under study. The ability of isolated L. plantarum strains to produce carotenoids in MRS broth was investigated. QS3 isolate gave the highest ability for production of carotenoids. Statistical screening of media components for production of carotenoids by L. plantarum QS3 using date syrup as a source of sugar was carried out using Plackett-Burman design. Date syrup at 5% sugar concentration produced 16.21 mg/kg dry cell of carotenoids when used alone. Increase in carotenoids production was recovered (54.89 mg/kg dry cell) with supplementation of MRS medium with salts and organic nitrogen after optimization of pH and temperature using date syrup as a carbon source. Plackett-Burman design showed peptone, K₂HPO₄, sodium acetate and date juice as main components affecting carotenoids production.  相似文献