Experiments on the rate of development of adventitious roots on Sambucus nigra cuttings

Abstract

The number of roots emerging daily from Sambucus nigra cuttings was maximal after about 2 weeks and subsequently declined to near zero. If the emerged roots were removed, however, further adventitious roots developed: repeated removal of all roots, or of the rooted base of the cutting, was followed by successive flushes of roots, and removal of every root as it emerged resulted in the initiation of adventitious roots continuing throughout experiments lasting 10 weeks or longer.

The results can be interpreted in terms of the initiation rate being related inversely to the number of existing roots, and a quantitative analysis shows that this interpretation can account not only for the time course of root emergence on normal cuttings but also for a damped oscillation observed in the rate of root emergence when emerging roots were continually removed.