Ornithine and arginine decarboxylases and polyamine involvement during in vivo differentiation and in vitro dedifferentiation of Datura innoxia leaf explants

Abstract

N. 1986. Ornithine and arginine decarboxylases and polyamine involvement during in vivo differentiation and in vitro dedifferentiation of Datura innoxia leaf explants. -Physjol. Plantarum 68: 589-596.The effects of exogenous ornithine, arginine and poiyamines added to media leading to root, callus or bud initiation of Datura innoxia Mill, leaf explants growing in vitro were examined. Omithine and arginine decarboxylase activities (ODC, EC 4.1.1. !7; ADC, EC 4.1.1.19) as well as endogenous polyamine levels were also determined during the course of in vivo differentiation of the leaves and their subsequent in vitro dedifferentiation utider rooting, callusing, or budding conditions. Decarboxylase activities were determined by measuring the '*CO, released and the polyamines were quantified after dansylation by thin-layer chromatography. In vivo, ODC and ADC activities decreased from shoots to young to old leaves, in vitro, synergistic effects between omithine and indole-3-acetic acid on rhizogenesis were detected, while arginine was not effective. Exogenous putrescine also acted synergistically with auxin by promoting root growth. A close relationship was found between rhizogenesis, OC>C activity and increase in endogenous putrescine and spermidine levels. ODC increased during the induction and time course of cell dedifferentiation and seemed to support these events, while ADC seemed to support only the later events involving redifferentiation.

Morphogenesis in tobacco subepidermal cells: Putrescine as marker of root differentiation

“…Changes in PA levels have also been described during root formation in Phaseolus mungo [1], tobacco callus [12,25], corn [18] and apple seedlings [32]. Arginine (a precursor of Put) has been found to be involved in auxininduced root formation in Hibiscus cuttings [31], while exogenous Put was found to act synergistically with auxin in promoting root differentiation in Datura innoxia leaf explants [3]. Furthermore, a combination of Put, Spd and Spm enhanced root development in Picea abies callus [20], while exogenous Spd and/or Spm were found to promote root formation in stem cuttings of mung bean [9,19].…”

Exogenous polyamines improve rooting of hazel microshoots

“…Rhizogenesis in culture of leaf explants of Datura innoxia increased due to a synergistic effect of ornithine and IAA (Chriqui et al 1986). …”

Polyamines, Hydroxycinnamoylputrescines, and Root Formation in Leaf Explants of Tobacco Cultivated in Vitro

“…The relationship among free polyamines, hydroxycinnamoylputrescines, cell division, and root formation is discussed. (10,14,25) suggest that polyamines are involved in auxin-induced root formation, although their specific role has yet to be elucidated in order to establish a causal relationship.Amides formed between hydroxycinnamic acids and amines are widely distributed in the plant kingdom (9,20,21,28). They are detected in high amounts in flowering parts ofvarious plants and have been linked to the process offlower formation (for reviews, see refs.…”

“…1398 Several reports (10,14,25) suggest that polyamines are involved in auxin-induced root formation, although their specific role has yet to be elucidated in order to establish a causal relationship.…”