TY - JOUR

T1 - Stimulation of adventitious root formation by laser wounding in rose cuttings

T2 - A matter of energy and pattern

AU - Morales-Orellana, Raul Javier

AU - Winkelmann, Traud

AU - Bettin, Andreas

AU - Rath, Thomas

N1 - Funding Information: This work was finantially supported by the research funding of the Hochschule Osnabrück, the Biosystem Engineering Laboratory (BLab) and the Section of Woody Plant and Propagation Physiology at the Leibniz Hannover University. Acknowledgments: We thank the reviewers for their insighful comments on this manuscript and all members of the Blab team at the Hochschule Osnabrück for help devising the imaging analysis process and the technical support during the design of the whole project. To all the members of the floriculture section of the Hochschule Osnabrück for the greenhouse facilities. We would like to thank all members of the Woody Plant and Propagation Physiology Section at the Leibniz University Hannover for the advice regarding microscopy and the supply of the plant material of R. canina ‘Pfänder’. Finally, a special thanks to Zahra Mohammadi Nakhjiri for the linguistic review of this article.

PY - 2022/9/29

Y1 - 2022/9/29

N2 - Adventitious root (AR) formation is the basis of vegetative propagation in rose, be it via stem cuttings or via stenting. During this process, wounding plays a pivotal role since cell reprogramming takes place at the tissue adjacent to the wound. We investigated the effects of wounding on AR formation on leafy single-node stem cuttings of the rose rootstock R. canina ‘Pfänder’ (codes R02-3 and R02-6) and the cut rose cultivar Rosa ‘Tan09283’ (Registration name ‘Beluga’). Laser wounding treatments were based on the assisted removal of tissue layers located in the bark. The positioning of wounding was studied based on two marking directions: along the cutting base (strip pattern) and around the cutting base (ring pattern). Additionally, the effects of external supply of indole-butyric acid (IBA 1 mg L-1) on rooting were analyzed. Results showed that in order to remove specific tissue layers, the calculation of the laser energy density (J cm-2) in terms of cutting diameter was necessary. Interestingly, the application of energy densities from 2.5 J cm-2 up to approximately 8.5 J cm-2 were sufficient to expose the tissue layers of epidermis up to regions of phloem. Regarding AR formation for R. canina ‘Pfänder’, characterized by a low rooting response, an increase in the rooting percentage was registered when the laser treatment eliminated the tissue up to phloem proximities. Analysis of the nodal position showed that bud location was a preferential place for AR formation independently of wounding treatment. In case of Rosa ‘Tan09283’, laser treatments did not reduce its high rooting capacity, but an apparent reduction in rooting quality due to an investment in tissue healing was observed when wounding reached deeper layers such as parenchyma and sclerenchyma. Results also showed a strong AR formation directly from wounded regions in case of Rosa ‘Tan09283’ specifically when the wound was located below the axillary bud. In conclusion, wounding by assisted-elimination of layers by laser can induce positive effects on AR formation of single-node stem cuttings of the rose if energy applied is able to expose phloem proximities, a longitudinal orientation, and relative position to the axillary bud are considered.

AB - Adventitious root (AR) formation is the basis of vegetative propagation in rose, be it via stem cuttings or via stenting. During this process, wounding plays a pivotal role since cell reprogramming takes place at the tissue adjacent to the wound. We investigated the effects of wounding on AR formation on leafy single-node stem cuttings of the rose rootstock R. canina ‘Pfänder’ (codes R02-3 and R02-6) and the cut rose cultivar Rosa ‘Tan09283’ (Registration name ‘Beluga’). Laser wounding treatments were based on the assisted removal of tissue layers located in the bark. The positioning of wounding was studied based on two marking directions: along the cutting base (strip pattern) and around the cutting base (ring pattern). Additionally, the effects of external supply of indole-butyric acid (IBA 1 mg L-1) on rooting were analyzed. Results showed that in order to remove specific tissue layers, the calculation of the laser energy density (J cm-2) in terms of cutting diameter was necessary. Interestingly, the application of energy densities from 2.5 J cm-2 up to approximately 8.5 J cm-2 were sufficient to expose the tissue layers of epidermis up to regions of phloem. Regarding AR formation for R. canina ‘Pfänder’, characterized by a low rooting response, an increase in the rooting percentage was registered when the laser treatment eliminated the tissue up to phloem proximities. Analysis of the nodal position showed that bud location was a preferential place for AR formation independently of wounding treatment. In case of Rosa ‘Tan09283’, laser treatments did not reduce its high rooting capacity, but an apparent reduction in rooting quality due to an investment in tissue healing was observed when wounding reached deeper layers such as parenchyma and sclerenchyma. Results also showed a strong AR formation directly from wounded regions in case of Rosa ‘Tan09283’ specifically when the wound was located below the axillary bud. In conclusion, wounding by assisted-elimination of layers by laser can induce positive effects on AR formation of single-node stem cuttings of the rose if energy applied is able to expose phloem proximities, a longitudinal orientation, and relative position to the axillary bud are considered.

KW - adventitious root formation

KW - histology

KW - laser ablation

KW - Rosa canina

KW - stem cutting

KW - wounding

UR - http://www.scopus.com/inward/record.url?scp=85140020638&partnerID=8YFLogxK

U2 - 10.3389/fpls.2022.1009085

DO - 10.3389/fpls.2022.1009085

M3 - Article

AN - SCOPUS:85140020638

VL - 13

JO - Frontiers in Plant Science

JF - Frontiers in Plant Science

SN - 1664-462X

M1 - 1009085

ER -