Conditions Aseptiques pour l'Endurcissement au Froid de Plantules de Blé d'Automne et de Luzerne

Abstract

Triticum aestivum L. and Medicago sativa L., cultivars Kharkov and Saranac respectively, were germinated in presence of different doses of fungicides. Benomyl and triadimenol did not affect the germination of winter wheat while aluminium phosphite and benomyl had non adverse effect on alfalfa. Imazalil and mephforuxam decreased the germination of both species and triadimenol affected the germination of alfalfa. Fenapanil (0, 5g a.i./kg seeds) did not affect the germination of both species. Fenapanil (0, 5g) did not affect the frost resistance (LT-50) of both species. The other fungicides decreased this LT-50. Fenapanil and imazalil (0, 5g) had no effect on the root apex cell ultrastructure of winter wheat. Benomyl (4g) induced the formation of vesicles in the nuclear membrane and in the endoplasmic reticulum. Further, the interphase nucleus chromatin displayed a flocculation pattern. The nucleolus granular zones also disappeared and only the fibrillar zones remained visible. Mephfuroxam treatment (2g) induced a strong cell plasmolysis. The nuclear membrane showed a wrinkled appearance and the chromatin adopted a dense and compacted pattern. As a result of treatments with triadimenol and aluminium ethylphosphite (2g) the fibrillar zones aggregated in the center of the nucleolus while the granular zones dispersed at the edge. Fenapanil (0, 5g) had no effect on alfalfa root apex cell ultrastructure.