Contribution à l'étude de l'effet des traitements chimiques et physiques sur la levée de dormance chez quelques adventices

Abstract

Le présent travail porte sur l’étude de la levé de dormance des graines d’adventices de Lavatera cretica, Bromus rubens, Polygonum aviculare et Melilotus indica. par différent traitement physiques (eau chaude, stratification au froid humide et enfouissement) et chimiques (acide sulfurique, acide gibbérellique). Des expériences ont été effectuées avec six temps de trempage dans l'acide sulfurique (15, 30, 45, 60 et 75 min) et le trempage dans l’ acide gibbérellique (500,1000, 1500, 2000 et 2500 ppm) pendent 24 h, le trempage dans l’eau chaud à100C pendent (6h et 15min) et stratification au froid humide pendant (1, 2, 3, 4, 5, 6 et7 jours), l’étude de l’effet de l'enfouissement durant (1, 2 , 3 et 4 mois) réalisé dans des boites remplis du sable. Après l'application de traitement les graines sont soumises au test de germination au phytotron à 25°C. Les résultats obtenus montrent qu'il y a une améliore de taux de germination des 4 espèces Melilotus indica le trempage dans l’acide sulfurique à 60min un taux maximale de germination 92%. Pour Lavatera cretica le trempage dans l’acide sulfurique pendant 75min donne un taux de 76.8%, le taux de germination de Bromus rubens est s'amélioré par la stratification (99.6%) et à 2000 ppm par un taux de 94%. Tandis que pour Polygonum aviculare le taux de germination après stratification de 7 jours enregistre 98.4% de germination et de 75.2% sous l'effet de GA3 à 2500 ppm. The present takes as an object the study of the dormancy of weed seeds of Lavatera Cretica, Bromus Rubens, Polygonum and Melilotus indica through different physical treatment (hot water, cold scarification wet and burial) and chemical (sulfuric acid) gibberellic acid). Experiments were carried out with six soaking times in sulfuric acid (15, 30, 45, 60 and 75 min) and dipping in gibberellic acid (500, 1000, 1500, 2000 and 2500ppm) for 24h, the soaking in hot water at 100 C ° hanging (6h and 15min) and stratification to wet cold during (1,2,3,4, 5, 6 and 7 days), the study of the effect of burial during ( 1.2, 3 and 4 months) made in boxes filled with sand, After the application of treatment the seeds are subjected to the germination test at 25 ° C. The obtained results show that there is an improvement in the germination rate of the 4 species Melilotus Indica soaking in sulfuric acid at 60min a maximum rate of germination 92%. For Lavatera Cretica soaking in sulfuric acid for 75min gives a rate of 76.8%, the germination rate of Bromus Rubens is improved by stratification (99.6%) and at 2000 ppm by a rate of 94%. While for Polygonum, the 7-day stratification germination rate recorded 98.4% germination and 75.2% GA3 at 2500 ppm.

The present takes as an object the study of the dormancy of weed seeds of Lavatera Cretica, Bromus Rubens, Polygonum and Melilotus indica through different physical treatment (hot water, cold scarification wet and burial) and chemical (sulfuric acid) gibberellic acid). Experiments were carried out with six soaking times in sulfuric acid (15, 30, 45, 60 and 75 min) and dipping in gibberellic acid (500, 1000, 1500, 2000 and 2500ppm) for 24h, the soaking in hot water at 100 C ° hanging (6h and 15min) and stratification to wet cold during (1,2,3,4, 5, 6 and 7 days), the study of the effect of burial during ( 1.2, 3 and 4 months) made in boxes filled with sand, After the application of treatment the seeds are subjected to the germination test at 25 ° C. The obtained results show that there is an improvement in the germination rate of the 4 species Melilotus Indica soaking in sulfuric acid at 60min a maximum rate of germination 92%. For Lavatera Cretica soaking in sulfuric acid for 75min gives a rate of 76.8%, the germination rate of Bromus Rubens is improved by stratification (99.6%) and at 2000 ppm by a rate of 94%. While for Polygonum, the 7-day stratification germination rate recorded 98.4% germination and 75.2% GA3 at 2500 ppm.