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51.
Rajaâ Jebbouj Brahim El Yousfi 《European journal of plant pathology / European Foundation for Plant Pathology》2009,125(2):303-315
This paper evaluates, in the greenhouse and under natural conditions, barley yield losses due to defoliation treatments of
the upper three leaves either healthy or infected at the boot stage by Pyrenophora teres f. teres. Defoliation was assumed as a loss of a similar leaf area caused by net blotch disease severity of 100%. Contribution to
grain yield was defined herein as a difference between defoliation treatments and a treatment where plants lost all their
upper three leaves. In contrast, yield losses referred to differences in yield between defoliations and the control. In the
greenhouse, removal of the antepenultimate leaf did not affect any yield component. For main stems, defoliating upper three
leaves reduced grain yield by 30% and this was mainly due to flag leaf removal. These losses were similar to those induced
by net blotch disease under natural conditions, but were of 42% for all tillers. Grain yield losses due to disease severity
were not equivalent to the defoliation effect of a similar healthy leaf area. On the other hand and for a significant contribution
to grain yield, flag leaf was dependent on the presence of the other two leaves. Inoculation and defoliation of 21 cultivars
induced similar grain yield losses of 32%. However, biotic stress reduced by 40% the contribution of their upper three leaves.
Under field conditions, yield losses were not significant until barley plants lost more than one upper leaf and flag leaf
contribution was equivalent to that of the remaining leaves. Characteristic roots, defined as leaf coefficients for plant
performance, were 0.13, 0.06 and 0.01 for the flag, penultimate and antepenultimate leaves, respectively. Because antepenultimate
leaves become trivial at the boot stage, we propose that coefficients of the remaining leaves should be used when modelling
yield losses due to barley foliar diseases. 相似文献
52.
Ibtissem Hamrouni Sellami Emna Maamouri Thouraya Chahed Wissem Aidi Wannes Mohamed Elyes Kchouk Brahim Marzouk 《Industrial Crops and Products》2009,30(3):395-402
The variation in the content and composition of Origanum majorana L. essential oil has been studied. Plant material has been harvested at four phenological stages (early vegetative, late vegetative, budding and full-flowering). Essential oil yield varied from 0.04 to 0.09% reached during the full-flowering stage. Analysis of the essential oils by GC and GC/MS revealed the presence of 38 components represented mainly by oxygenated monoterpenes (64.01–71.4%), monoterpene hydrocarbons (21.73–29.92%) and sesquiterpene hydrocarbons (1.47–4.05%). The main components were terpinen-4-ol (29.13–32.57%), cis-sabinene hydrate (19.9–29.27%), trans-sabinene hydrate (3.5–11.61%), γ-terpinene (2.11–8.20%), bornyl acetate (1.52–2.94%) and linalool (1.05–1.39%). On the other hand, phenolic contents varied from 2.706 to 6.834 mg/g of dry weight obtained during the later vegetative stage. RP-HPLC analysis of the methanolic extract of O. majorana L. dried aerial parts showed the predominance of phenolic acids during the early vegetative stage whereas flavonoids predominate during the other stages of growth. The main phenolic acids identified were trans-2-hydroxycinnamic, rosmarinic, vanillic, chlorogenic, gallic and cinnamic whereas the main flavonoids were amentoflavone, apigenin, quercetin, luteolin, coumarin and rutin. Results obtained showed that later vegetative stage is characterized by the highest contents of bioactive compounds and therefore it could be considered as the best stage for harvesting marjoram plants. 相似文献
53.
Bettaieb I Knioua S Hamrouni I Limam F Marzouk B 《Journal of agricultural and food chemistry》2011,59(1):328-334
This study is designed to examine the effect of water deficit on growth, fatty acid and essential oil composition, and antioxidant activities of Cuminum cyminum aerial part extracts. Plants were treated with different levels of water deficit: control (C), moderate water deficit (MWD), and severe water deficit (SWD). Plant growth (height, fresh and dry matter weights) as well as yield components were significantly increased under moderate water deficit and conversely reduced at severe level. Total fatty acid content decreased significantly with severity of constraint. Drought reduced considerably the proportions of major fatty acids and the unsaturated to saturated fatty acid ratio. The essential oil yield was 0.14% (based on the dry weight); it increased by 2.21-fold at MWD but decreased by 42.8% under SWD in comparison to the control. Drought results in the modification of the essential oil chemotype from 1-phenyl-1-butanol to 1-phenyl-1,2-ethanediol. Antioxidant activities of the acetone extracts were determined by two complementary test systems, namely, DPPH and β-carotene/linoleic acid. The highest activity was exhibited by moderately stressed plants and was reduced significantly under SWD. In control plants, the total phenolic amount was 10.23 mg GAE/g DW, which increased by 1.5-fold under MWD and decreased by 42% under SWD. 相似文献
54.
AbstractSuccessful fruit fly control requires effective monitoring to make pest management decisions. Ceratitis capitata (Medfly) is typically monitored in Tunisia with parapheromone commercialised as trimedlure (TM). Chemical treatment is applied when the economic threshold (3 flies/trap/day) is reached. In this study, C. capitata populations in a commercial citrus orchard captured in McPhail traps baited with TM or enriched ginger oil (EGO) were compared over two seasons (2011 and 2012). Females of C. capitata were not attracted to TM or EGO. Trimedlure was significantly more attractive to C. capitata males than EGO under low and high population densities over sampling dates. The TM used in McPhail traps was adequate to attract male medflies in citrus orchards under a wide range of Medfly population levels. The use of the best attractant can help to make control decisions when population levels of flies are low, thus preventing unnecessary application of insecticides and/or other control methods. 相似文献
55.
Kamel Msaada Mouna Ben Taarit Karim Hosni Mohamed Hammami Brahim Marzouk 《Scientia Horticulturae》2009
The composition of volatile components of the essential oils extracted from fruits of coriander (Coriandrum sativum L.) growing in two different Tunisian regions in both Menzel Temime and Borj El Ifaa was studied by GC and GC–MS. The highest oil yields were observed at final stages of maturity: 0.324 ± 0.09% and 0.327 ± 0.08%, in Menzel Temime and Borj El Ifaa, respectively. Essential oil yields were highly (P < 0.001) affected by the growing region, stages of maturity and their interaction. Essential oil composition changed significantly (P < 0.05) among the different stages of maturity and growing region. Linalool and geranyl acetate were the main compounds at full fruit maturity in the two studied regions. Growing region, stages of maturity and their interaction had a strong effect (P < 0.001) on 35 compounds. α-Pinene, sabinene, limonene, γ-terpinene, cis-dihydrocarvone and geranial were insensible to the regional factor. 相似文献
56.
El Antri A Messouri I Bouktaib M El Alami R Bolte M El Bali B Lachkar M 《Fitoterapia》2004,75(7-8):774-778
A new isoquinoline-N-oxide alkaloid was extracted from the alkaloid fraction of a methanol extract of the seeds of Calycotome villosa subsp. intermedia. Its structure was established as 1-hydroxymethyl-6,7-dimethoxyisoquinoline-N-oxide (1) by spectroscopic techniques and X-ray diffraction analysis. 相似文献
57.
Changes in essential oil and fatty acid composition in coriander (Coriandrum sativum L.) leaves under saline conditions 总被引：2，自引：1，他引：1
The influence of salinity on essential oil and fatty acid composition of Tunisian coriander (Coriandrum sativum L.) leaves grown in hydroponic culture was investigated. Volatile constituents and fatty acid of leaves were analyzed. The essential oil yield increased significantly up to 18 and 43% with 25 and 50 mM NaCl, respectively and decreased significantly under high salinity. The major volatile compound in leaves was (E)-2-decenal with 52% of total essential oil constituents, followed by decanal, dodecanal, (E)-2-tridecenal and (E)-2-dodecenal. Further, the content of these compounds was affected differently by the treatment level.Salinity decreased significantly the total fatty acid content of the upper and basal leaves. α-Linolenic (C18:3n3) was the main compound of both organs, followed by linoleic (C18:2n6), heptadecenoïc (C17:1n7) and palmitic (C16:0) acids. Raising NaCl concentrations lead to an important decrease in the unsaturated to saturated fatty acid ratio stimulating the formation of more rigid membrane. 相似文献
58.
Soumaya Rhouma Sonia Dakhlaoui-Dkhil Ali Ould Mohamed Salem Salwa Zehdi-Azouzi Abdelmajid Rhouma Mohamed Marrakchi Mokhtar Trifi 《Scientia Horticulturae》2008
Random amplified microsatellite polymorphisms (RAMPOs) were used to assess genetic diversity among 30 date-palm cultivars and 10 male trees. Using 18 primers combinations, 197 bands were scored and 186 were polymorphic suggesting the high level of polymorphism among studied cultivars. Moreover, taking into account the high percentage of polymorphic bands (ppb), the resolving power (Rp) together with the polymorphism information content (PIC) scored values, all the tested primer sets contribute strongly in the discrimination of date-palm genotypes. In addition, the topology of the derived UPGMA dendrogram exhibited cultivars’ clustering made independently both from the geographical origin and/or from the sex of trees. The present data support the Mesopotamian origin of the date-palm domestication. Thus we assume that the used method is efficient to assess genetic diversity within date-palm cultivars. Data are discussed in relation with the opportunity of the RAMPO method to provide additional molecular markers suitable in the improvement of the date-palms germplasm characterisation. 相似文献
59.
不同方法及材料检测大片吸虫感染的比较试验 总被引：4，自引：2，他引：2
为片形吸虫病诊断提供高效、简便的新技术，以大片吸虫分泌排泄抗原（ES抗原），用于斑点酶联免疫吸附试验（Dot－ELISA）、琼脂扩散酶联免疫吸附试验（Dig－ELISA）、免疫胶体金滴渗法（DIGFA）检测动物体内的大片吸虫（Fasciolagigantica）感染。通过检测血清、血纸、牛奶等几种材料，多重试验比较，结果三种方法均具有敏感性高、特异性强、准确性可靠等优点，并各有特长，如操作简便快速、费用低廉，易于在基层推广应用等，同时证明用血纸和牛奶检测抗体效果同样可靠。本试验首次报道用Dot－ELISA、DIGFA在奶中检测片形吸虫抗体，为该寄生虫病普查提供一种新思路。 相似文献
60.
Karim Hosni Marwa JemliSalma Dziri Yacine M’rabetAsma Ennigrou Ahlem SghaierHervé Casabianca Emmanuelle VullietNadia Ben Brahim Houcine Sebei 《Industrial Crops and Products》2011,34(3):1622-1628
The effect of stage of maturity on total lipids, fatty acids, yields and essential oil composition and their antimicrobial and free radical scavenging activities of the Schinus molle fruits was investigated. The content of total lipids varied from 2.87 to 5.35% (w/w, dw) and were rich in unsaturated fatty acids particularly linoleic acid. As maturation progress, the essential oil yield dropped from 5.18% to 1.15%. Monoterpene hydrocarbons with α-phellandrene (35.15-40.38%), limonene + β-phellandrene (21.47-36.62%), β-myrcene (7.61-24.96%) and α-pinene (1.92-2.58%) were found to be the main components. At the same time, the essential oils were evaluated for their antimicrobial and free radical scavenging activities. They were found to be active against Bacillus subtilis, Bacillus cereus, Salmonella typhymurium and Escherichia coli but they do not inhibit the growth of Candida albicans. Conversely, they showed very weak activity against the DPPH radical. In both assay, the oil derived from the intermediate stage was reported as more efficient. 相似文献