Development of Lateral Primordia in Decapitated Adventitious Roots of Allium cepa

In decapitated adventitious roots of Allium cepa L. var. French,the time taken for lateral primordia to appear in five sectorshas been studied. This time is approx. 4–5 d after theapex of the adventitious root gave rise to the primordial initialcells. Allium cepa, adventitious root, lateral primordia     

Cell Wall Thickening of the Xylem Tracheary Elements in Different Zones of the Adventitious Root of Allium cepa L.

Cell wall thickness of the xylem tracheary elements was measuredin the proto- and metaxylem of the Allium cepa L. adventitiousroot. Measurements were taken in root fragments of known age(1, 3, 5, 7 and 9 d) located in either the basal or medio-apicalzone. Tracheary elements in the protoxylem matured within ashorter period of time than those in the metaxylem. Final cellwall thickness was greater in metaxylem than in protoxylem components.The cell wall thickening in the tracheary elements in both proto-and metaxylem was more rapid in the basal zone of the root thanin the medio-apical zone. Additionally, cell walls of the maturetracheary elements were thicker in the basal zone than in areasfurther from the bulb. Allium cepa, onion, root, cell wall, xylem maturation