Regenerative Capacity of Root Fragments of Cirsium Arvense (L.) Scop.

Summary. Root fragments less than 5 mm long were unable to form shoots. However, shoots were produced by fragments 10 mm long and 1 mm in diameter, unless originating from immature apical regions. The number of shoots per unit length of root was greater if the root was cut into many small pieces than into a few long ones. The ability to produce shoots was apparently unrelated to the presence or absence of visible buds. Root fragments showed polarity; most of the shoots originated from the basal (proximal) end and the roots from the apical (distal) end. Soil moisture content had relatively little effect upon growth from a fragment unless the soil was waterlogged or very dry for prolonged periods. Growth from fragments was prevented by temperatures below 5°C; optimum growth occurred at 15°G. Shoots from fragments 25 mm long emerged successfully from depths of 50 cm. Capacité de régenération de fragments de racines de Cirsium arvense (L.) Scop.