One- to four-year-old callus cultures of the Lombardy poplar (Populus nigra L. ’Italica‘) are able to form roots and leaves or shoots. There may be single leaves, small buds, elongating shoots, or a combination of these organs. Of the four cytokinins used to stimulate organ formation, zeatin was the most active, stimulating shoot formation at a concentration as low as 10~8 M. The highest zeatin and BA concentrations (I0~5 M) stimulated leaf formation, but fewer elongated shoots were formed than at a lower cytokinin concentration. 2,4-D was inhibitory to organ formation, even in low concentrations that stimulated callus growth (0.05- 0.1 mg/1). This 2,4-D-inhibition is discussed in relation to the suppression of tissue differentiation.

Acta botanica neerlandica

CC BY 3.0 NL ("Naamsvermelding")

Koninklijke Nederlandse Botanische Vereniging

Catharina J. Venverloo. (1973). The formation of adventitious prgans. I. Cytokinin-induced formation of leaves and shoots in callus cultures of Populus nigra L. ‘Italica’. Acta botanica neerlandica, 22(4), 390–398.