Magistère (Biologie et Ecologie végétale)

Caractère << aberrant >>chez le chou-fleur(Brassica oleracea L.var.Bortrytis)

2005-03-24T00:00:00Z

Caractère << aberrant >>chez le chou-fleur(Brassica oleracea L.var.Bortrytis); Aneuploidie et épigénétisme MISSI Nadjette; KHELIFI D.; CHABLE V. Since 10 years, studies of aberrant plants in cauliflower have been performed to identify their origin. We try to find the common characters to the numerous phenotypes of the aberration. The reversibility and the non mendelian transmission of the plant perturbations suggested an epigenetic phenomenon. First analysis showed a DNA méthylation polymorphism and, in some of them, a variation of the DNA quantity, with one or two more chromosomes, and even with the loss of DNA. To estimate tire link of aberration to aneuploidy for two varieties, Neven and Nominoé, several methods of cytogenetical analysis have been associated to establish the reliability and the precision of the data obtained by flow cytometry. Only, the plants presented a loss of DNA (-5.8% to -2.5%) have not been observed at mitotic or meiotic stages because of their great development perturbations. The type of aneuploidy could vary for the same plant during its development, and the rate of aneuploids was different from one variety to another during the different stages of the development. The modifications of the DNA quantity have not always been link to morphological variations. Partial data of the rate methylated cytosine have been obtained by HPLC measures. These data would indicate a hyperméthylation of the aberrant plant DNA. Nevertheless, the method still needs to be improved for cauliflower. For the study of the systemic transmission of the aberration or the reversion to normality, a grafting experience allowed to show interactions between scion and stock, and in the two ways, either they were normal or aberrant, contrary to the known systemic transmission of gene silencing . 49 f.

Evaluation de la qualité des eaux d’irrigation

2012-01-01T00:00:00Z

Evaluation de la qualité des eaux d’irrigation Bouaroudj Sara; Kadem Dhaou-El-Djabine In Constantine, the re-use of rough used water in irrigated agriculture back to dates 1970 and is always of actuality in spite of the effective law prohibiting the use of these waters. In the course of this study, used water, of the two principal wadis: Rhumel (O.R) and Boumerzoug (O.B), used for irrigation, in two agricultural stations, have been subject of a qualitative evaluation. The stations differ by their geographical place where the influence of human and industrial activity is not the same from one station to another. The methodology followed in the evaluation of the quality of these waters is the one recommended by the FAO. Compared to the directives of the FAO, The results found, have reveale d some "anomalies" that might be at the origin of agronomic problems (salinity), pedological (permeability) and of toxicity,due to excessive contents of sodium, chlor ine, bicarbonate and azote. The problem of salinity is encountered in both stations the result established is that the practice of irrigation of irrigation happens in an anarchic way without any prior study of evaluating water quality. The farmers irrigate several types of cultures without the least control. Henceforth, a rule is necessary to know: all supplies with wastewater intended to irrigation must be the subject, not only of a prior qualitative evaluation, but should encourage farmers for more rigors in the management and control of irrigation. If farmers can always use these waters for irrigation, it is their responsibility to take certain precautions. They must: (1) ensure that their soils present a sufficient permeability, (2) demonstrate competence in terms of irrigation (date, dose, frequency). Failing this, avoid growing plants sens itive to salt and to plant only “tolerant “. Otherwise, the competent authorities have the right to apply the”Precautionary Principe” 75 f.

Evaluation des teneurs en nitrates dans les sols et dans les eaux captées et émergentes en zones à vocation agricole

2012-01-01T00:00:00Z

Evaluation des teneurs en nitrates dans les sols et dans les eaux captées et émergentes en zones à vocation agricole; Impact des nitrates sur la qualité des eaux destinées à la consommation humaine Alouane Hind; Kadem Dhaou-El-Djabine 79 f.

Qualité physico-chimique, pollution organique et métalliquedes compartiments Eau / Sédiments de l’Oued Rhumel,et des barrages Hammam Grouz et Beni Haroun

2012-01-01T00:00:00Z

Qualité physico-chimique, pollution organique et métalliquedes compartiments Eau / Sédiments de l’Oued Rhumel,et des barrages Hammam Grouz et Beni Haroun Melghit Meriem; Afri-Mehennaoui F. Zohra This study is part of the context of a multidisciplinary research on terrestrial and aquatic ecosystems. To assess the quality of water of the Rhumelwadi, its tributaries and the water dams HammamGrouzand BeniHaroun, to the organic pollution and possible metal contamination, we conducted for water and sediment compartments a set of physico-chemical approaches: physical and chemical parameters, major mineral elements, pollution parameters and dosage of five ETM (Cd, Cr, Cu, Pb and Zn). This research involved five sampling points for the water compartment, both located at the two dams GrouzHammam and BeniHaroun, and three on the Rhumelwadi, collected twelve times during 2009. For the sediment compartment, sixteen sampling points were selected in strategic locations and sampled twice during the month of January 2010 and April 2010. The set of parameters determined showed organic pollution characterized by fair to poor quality water from the wadiRhumel. Metallic contamination evaluated by SEM is almost negligible dissolved in water but fairly abundant in sediments which could cause high toxicity for aquatic fauna and flora, mainly marked by levels of Cd, Cr, Zn and Pb higher than the estimated natural levels. The waters of dams HammamGrouzandBeniHaroun are exposed to pollution from various sources (urban,industrial and agricultural ...) despite treatment of wastewater in STEP. Their sediments show a significant metal contamination. A similar situation is observed for the waters of Rhumelwadi and its tributaries, where the degree of pollution is important. To remedy this problem, it would be important to better exploit the wastewater treatment plants, a wastewater collection and mastered most comprehensive, well while managing industrial and municipal discharges, which undoubtedly constitute a major threat to ecosystems aquatic. The purified water supply Rhumelwadi, its tributaries and therefore the two dams HammamGrouzandBeniHaroun. They contribute to the reduced risk of organic pollution and heavy metal contamination of water and sediment compartments, and water conservation for serene life (better water management). 176 f.