Articles
SUCCESSIVE PHASES DURING ROOTING OF MICROCUTTING OF MALUS
Article number
336_32
Pages
249 – 256
Language
Abstract
Regeneration of roots occurs in three phases, viz., dedifferentiation, differentiation and outgrowth.
It is likely that cytokinin interferes with the second phase.
On this principle we determined the timing of the differentiation phase in microcuttings of Malus ‘Jork’ rooted at 20/deC with 1 μM indolebutyric acid (IBA). Benzylaminopurine (BAP) (2 μM) given as a 24-h pulse, had a strong inhibitory effect between 24 and 96 h with maximum inhibition in the pulse at 48–72h.
In disks excised from stems of microcuttings and rooted at 25°C by a 24-h treatment with 25 μM IBA directly after excision, the differentiation phase was somewhat advanced.
It has been found previously that in disks the first cell divisions occur 24 to 48 h after excision.
Shoots cultured on basal medium were given 24-h pulses with IBA. Best rooting was obtained after the pulses at 24-48 h and 48–72 h.
However, the promotive effect of IBA was not as distinct as the inhibitory effect of BAP, and was observed only in pulses with a high concentration of IBA (3 μM). The synthetic auxin 2,4- dichlorophenoxyacetic acid (2,4-D) inhibited rooting in the outgrowth phase.
It is likely that cytokinin interferes with the second phase.
On this principle we determined the timing of the differentiation phase in microcuttings of Malus ‘Jork’ rooted at 20/deC with 1 μM indolebutyric acid (IBA). Benzylaminopurine (BAP) (2 μM) given as a 24-h pulse, had a strong inhibitory effect between 24 and 96 h with maximum inhibition in the pulse at 48–72h.
In disks excised from stems of microcuttings and rooted at 25°C by a 24-h treatment with 25 μM IBA directly after excision, the differentiation phase was somewhat advanced.
It has been found previously that in disks the first cell divisions occur 24 to 48 h after excision.
Shoots cultured on basal medium were given 24-h pulses with IBA. Best rooting was obtained after the pulses at 24-48 h and 48–72 h.
However, the promotive effect of IBA was not as distinct as the inhibitory effect of BAP, and was observed only in pulses with a high concentration of IBA (3 μM). The synthetic auxin 2,4- dichlorophenoxyacetic acid (2,4-D) inhibited rooting in the outgrowth phase.
Authors
G. Klerk, J. Brugge, M. Keppel
Keywords
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