Ethylene Production in Debladed Petioles from the Juvenile and Mature Phases of English Ivy in Relation to Adventitious Root Initiation

Abstract

<jats:p>Exogenous ethylene could not substitute for NAA to induce adventitious root initiation in juvenile petiole explants of English ivy <jats:italic>(Hedera helix</jats:italic> L.), indicating that the action of auxin-stimulated root initiation was not directly mediated through ethylene production. Mature petioles did not initiate roots under any auxin or ethylene treatment combination. Ethephon or ACC supplied at 50 or 100 μ<jats:sc>m</jats:sc> was inhibitory to NAA-induced root initiation in juvenile petioles. The pattern of ethylene production stimulated by NAA application was significantly different in juvenile and mature petioles. Ethylene evolution by juvenile petioles declined to near control levels during from 6 to 12 days after NAA application. Reduction in ethylene production was due to reduced availability of ACC in juvenile petioles. Mature petioles continued to produce ethylene at elevated levels throughout the course of the experiment. Ethylene does not appear to play a significant role in the differential root initiation response of juvenile and mature petioles treated with NAA. However, ethylene appeared to have an inhibitory effect during root elongation stages of adventitious root development in juvenile petioles. Chemical names used: 1-aminocyclopropane-1-carboxylic acid (ACC); 1-napthaleneacetic acid (NAA); 2-chloroethylphosphonic acid (ethephon).</jats:p>

Promotion of petunia (Petunia hybrida L.) regeneration in vitro by ethylene

“…Although ethylene at low levels of exogenous applications (0.01-1 ppm) did not influence rooting of petunia microshoots in an auxin-free medium, it induced adventitious root formation considerably at a concentration of 10 ppm without any effect on the root length. The contradictory experimental results in the literature (Krishnamoorthy 1970(Krishnamoorthy , 1972Roy et al 1972;Coleman et al 1980;Robbins et al 1983;Geneve et al 1990) support the hypothesis that the influence of exogenous ethylene on adventitious root formation varies with the plant species and the physiological and environmental conditions (Moncousin et al 1989;Mudge 1989).…”

“…However, in cultures of several plant species in vitro ethylene did not favour rooting. Thus, exogenous ethylene did not induce adventitious root initiation in juvenile and mature petiole explants of Hedera helix (Geneve et al 1990). Furthermore, the ethylene precursor aminocyclopropane-l-carboxylic acid (ACC) caused a marked reduction in rooting of cherry shoot cultures (Biondi et al 1990).…”

The influence of ethylene on in vitro rooting of GF 677 (Prunus persica × Prunus amygdalus) hybrid peach rootstock

“…In general, a small amount of ethylene supplied at the precisely correct developmental time promotes rooting, whereas higher ethylene levels at the wrong time or for too long a period inhibits rooting (Coleman et al, 1980;Geneve and Heuser, 1983;Biondi et al, 1990;Geneve et al, 1990;Liu et al, 1990;Gonzales et al, 1991;Dimasi-Theriou et al, 1993).…”

Ethylene Does Not Promote Adventitious Root Initiation on Apple Microcuttings

“…However, research results remain inconsistent. Ethylene can be stimulatory (Jusaitis, 1986;Riov and Yang, 1989;Robbins et al, 1983Robbins et al, , 1985, inhibitory (Geneve and Heuser, 1983;Geneve et al 1990a), or without relationship (Batten and Mullins, 1978;Mudge and Swanson, 1978) to adventitious rooting. Explanation, in part, may reside in experimental protocols and genetically variable plant material.…”

“…bioassay (Hess, 1968). Few studies used woody species (Moncousin et al, 1989;Swanson, 1974) or difficult-to-root plants (Geneve et al, 1990a(Geneve et al, , 1990b.…”