Stimulation of Adventitious Rooting in Cuttings of Four Herbaceous Species by Piperazine

Piperazine, a chemical used as buffer component, greatly promotedadventitious root formation in cuttings of sunflower (Helianthusannuus L.), pea (Pisum sativum L.), mung bean (Vigna radiataL.) and to a lesser extent in bean (Phaseolus vulgaris L.) seedlings.Piperazine was more effective in acidic pH. The studies withpiperazine analogues showed that any substantial modificationof the structure caused the chemical to be less effective, oreven inhibitory. Histological studies in sunflower hypocotylsdemonstrated that piperazine did not alter the timing of theinitial cell division. In the presence of piperazine, sunflowerhypocotyls failed to develop primary phloem fibres. Piperazineat the concentrations that promote rooting did not kill or damagethe tissue at the base of the hypocotyl. Compared to controls,piperazine treatment did not alter the proportion of primordiathat eventually developed into actively elongating roots. Sixdays after treatment 45% of the control roots in the basal sectionwere actively growing, compared to 51% in the piperazine. Therewas little evidence suggesting that the piperazine-induced promotionof rooting was caused by the removal of basal dominance in whichpiperazine killed the basal part of hypocotyl.Copyright 1995,1999 Academic Press Helianthus annuus, Phaseolus vulgaris, Pisum sativum, Vigna radiata, adventitious roots, mung bean, pea, piperazine, sunflower