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Hammam Sousse, Tunisia

Mabrouk S.,University of Monastir | Mabrouk S.,Higher Institute of Agronomy | Elaissi A.,University of Monastir | Ben Jannet H.,University of Monastir | And 2 more authors.
Natural Product Research | Year: 2011

The essential oils isolated at the flowering stage in spring, summer and autumn of the aerial and underground parts of Conyza bonariensis L. growing in Tunisia were analysed by GC and GC/MS; 143 constituents were identified, and among them 20 were major. The oils of C. bonariensis gathered in spring were rich in matricaria ester (1.2-67.3%), (Z)-nerolidol (0.3-19.9%) and caryophyllene oxide (0.8-14.3%). In the summer samples, the oils of C. bonariensis were rich in matricaria ester (1.6-76.4%), caryophyllene oxide (1.6-22.6%) and (E) - farnesene (1.1-22.7%). The main constituents in the autumn samples were matricaria ester (trace to 63.5%), geranyl acetone (0.0-25.3%), trans - bergamotene (0.0-24.3%) and limonene (2.7-15.3%). The oils showed significant variation among the seasons. Remarkable differences were found between the constituent percentages of the different studied organs. The C. bonariensis sample from Tunisia was a matricaria ester chemotype and was quite different from the samples of other countries of origin. © 2011 Taylor & Francis.


Elaoud A.,Higher Institute of Agronomy | Chehaibi S.,Higher Institute of Agronomy
Journal of Failure Analysis and Prevention | Year: 2011

Horticulture in Mediterranean areas demand frequent tractor traffic for tillage and for the application of herbicides and pesticides, resulting in soil compaction. Soil compaction is one of the most important factors responsible for soil physical degradation. This compaction by agricultural machines can have adverse effects on crop production and the environment. Different methods have been proposed to estimate soil compaction intensity as a function of vehicle and soil properties such as the soil's water content, bulk density, and resistance to penetration. In this work the authors studied subsoil compaction based on wheel load in the terrain tillage and tillage in a region that was not previously cultivated. A small tractor (engine power 25 kW, type E-TCVS, and weight 1200 kg) was used in the tests. Results showed that the first passage of wheel traffic of the tractor, increases the soil resistance more than the second passage; for example, there is a big difference between the penetration resistance at initial state (2.22 daN/cm 2) and after the first passage (5.72 daN/cm 2), while the variation between the penetration resistance after first passage (5.72 daN/cm 2) and after second passage (6.22 daN/cm 2) is relatively small. This shows that the first passage has the most significant impact on soil compaction. © 2011 ASM International.


Besma B.D.,Higher Institute of Agronomy | Mounir D.,Higher Institute of Agronomy
Journal of Agronomy | Year: 2010

The present research has studied the effects of NaCl and temperature on germination and emergence of okra. Studies were carried out with seeds of a local okra variety (Marsaouia) subjected to 0 and 100 mM NaCl, performed in the dark at 10, 15, 25, 35 and 40°C at germination stage and by 12 h light at emergence stage. The cumulative germination percentage, the cumulative emergence percentage, starch content, the reducing sugars levels, total amylase activity, sodium and potassium accumulation were quantified in germinated seeds at 15°C, 25 and 35°C. Temperature presented a significant effect on salt sensitivity of this species at germination and emergence stages. Germination of okra seeds was completely inhibited at 10 and 40°C. The best germination and emergence temperature was recorded at 25°C. The adverse effect of salt was more pronounced at low and high temperature. During the salt stress treatment, the level of starch reserves was higher at 25°C and lower at 15 and 35°C, an increase in reducing sugars content in cotyledons was observed. The activity of total amylase was most intensive at lower temperature in control seeds and at higher temperature in salt treated seeds. The sodium concentration on germinated seeds increased significantly at 15 and 35°C, but potassium amount did not change regularly within thermal and salt stress interaction. © 2010 Asian Network for Scientific Information.


Dkhil B.B.,Higher Institute of Agronomy | Denden M.,Higher Institute of Agronomy
African Journal of Agricultural Research | Year: 2010

During germination stage, the influence of NaCl on cumulative germination percentage, starch, total soluble sugar and phenol content in okra (Abelmoschus esculentus (L.) Moench, cultivar Marsaouia) seeds and growth seedlings components (cotyledons and embryonic axes) were studied. Seeds were sown in Petri dishes with varying concentrations of saline solutions (0, 20, 40, 60, 80 and 100 mM NaCl) at 25°C. Seed germination decreased significantly with the increase in NaCl concentration, optimal germination percentage occurred in non saline solution reaching 100%. There was more accumulation of sugar and phenol, starch level decreased markedly especially in cotyledons along with lower amylase activity. Amounts of sodium increased but amounts of potassium did not change significantly with increasing stress. © 2010 Academic Journals.


Dkhil B.B.,Higher Institute of Agronomy | Denden M.,Higher Institute of Agronomy
African Journal of Agricultural Research | Year: 2010

During germination stage, the influence of NaCl on cumulative germination percentage, starch, total soluble sugar and phenol content in okra (Abelmoschus esculentus (L.) Moench, cultivar Marsaouia) seeds and growth seedlings components (cotyledons and embryonic axes) were studied. Seeds were sown in Petri dishes with varying concentrations of saline solutions (0, 20, 40, 60, 80 and 100 mM NaCl) at 25°C. Seed germination decreased significantly with the increase in NaCl concentration, optimal germination percentage occurred in non saline solution reaching 100%. With increasing stress, there was more accumulation of sugar and phenol, starch level decreased markedly especially in cotyledons along with lower amylase activity. Amounts of sodium increased but amounts of potassium did not change significantly with increasing stress. © 2010 Academic Journals.

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