Etiolation and flooding of donor plants enhance the capability of Arabidopsis explants to root

Frans A Krens,Richard G F Visser,Geert-Jan M De Klerk,Mehdi Massoumi

doi:10.1007/s11240-017-1244-1

Frans A Krens, Richard G F Visser + Show 2 more

Open Access

https://doi.org/10.1007/s11240-017-1244-1

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Abstract

Rooting of cuttings depends not only on the rooting treatment and the genotype, but also on the condition of the cuttings at the time of excision. The physiological and developmental conditions of the donor plant may be decisive. We have examined in Arabidopsis the effect of two donor plant pre-treatments, etiolation and flooding, on the capability of flower stem and hypocotyl segments to root. For etiolation, plantlets were kept in the dark, hypocotyls up to 12 days and plantlets for 12 weeks. Flooding was applied as a layer of liquid medium on top of the semi-solid medium. This procedure is also referred to as “double layer”. Both pre-treatments strongly promoted rooting and we examined possible mechanisms. Expression of strigolactone biosynthesis and signaling related genes indicated that promotion by etiolation may be related to enhanced polar auxin transport. Increased rooting after flooding may have been brought about by accumulation of ethylene in the cutting (ethylene has been reported to increase sensitivity to auxin) and by massive formation of secondary phloem (the tissue close to which adventitious roots are induced). Both pre-treatments also strongly lowered the endogenous sucrose level. As low sucrose favors the juvenile state and juvenile tissues have a higher capability to root, the low sucrose levels may also play a role.

Highlights

Vegetative propagation is the predominant propagation method in horticulture and forestry and various major agricultural crops (Hartmann et al 2011)
Since cuttings that are excised from the donor plants obviously have no roots, adventitious root (AR) formation is indispensable in vegetative propagation (De Klerk et al 1999b)
We studied mechanisms underlying the effect of etiolation, a donor plant pre-treatment, on AR formation of Arabidopsis explants cultured in vitro

Summary

Introduction

Vegetative propagation is the predominant propagation method in horticulture and forestry and various major agricultural crops (Hartmann et al 2011). Since cuttings that are excised from the donor plants obviously have no roots, adventitious root (AR) formation is indispensable in vegetative propagation (De Klerk et al 1999b). Treatment with auxin is the common way to induce ARs (De Klerk et al 1999a), but a significant number of crops is recalcitrant to this treatment. An alternative way to increase rooting is donor plant pretreatment aiming at cuttings with an increased capability to respond to auxin. In this context, we have previously examined rejuvenation of donor plants (Massoumi et al 2017). We deal with etiolation and with flooding, the other two rooting promoting pre-treatments (De Klerk 2002)

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