scholarly journals Involvement of the auxin–cytokinin homeostasis in adventitious root formation of rose cuttings as affected by their nodal position in the stock plant

Planta ◽  
2021 ◽  
Vol 254 (4) ◽  
Author(s):  
Millicent A. Otiende ◽  
Klaus Fricke ◽  
Julius O. Nyabundi ◽  
Kamau Ngamau ◽  
Mohammad R. Hajirezaei ◽  
...  

Abstract Main conclusion Enhanced levels of indole-3-acetic and raised auxin to cytokinin ratios in the stem base contribute to the positive acropetal gradient in rooting capacity of leafy single-node stem cuttings of rose. Abstract Cuttings excised from different nodal positions in stock plants can differ in subsequent adventitious root formation. We investigated the involvement of the auxin–cytokinin balance in position-affected rooting of Rosa hybrida. Leafy single-node stem cuttings of two rose cultivars were excised from top versus bottom positions. Concentrations of IAA and cytokinins were monitored in the bud region and the stem base during 8 days after planting using chromatography–MS/MS technology. The effects of nodal position and external supply of indole-butyric acid on rooting were analyzed. Most cytokinins increased particularly in the bud region and peaked at day two before the bud break was recorded. IAA increased in both tissues between day one and day eight. Top versus bottom cuttings revealed higher levels of isopentenyladenosine (IPR) in both tissues as well as higher concentrations of IAA and a higher ratio of IAA to cytokinins particularly in the stem base. The dynamic of hormones and correlation analysis indicated that the higher IPR contributed to the enhanced IAA in the bud region which served as auxin source for the auxin homeostasis in the stem base, where IAA determined the auxin–cytokinin balance. Bottom versus top cuttings produced lower numbers and lengths of roots, whereas this deficit was counterbalanced by auxin application. Further considering other studies of rose, it is concluded that cytokinin-, sucrose- and zinc-dependent auxin biosynthesis in the outgrowing buds is an important factor that contributes to the enhanced IAA levels and auxin/cytokinin ratios in the stem base of apical cuttings, promoting root induction.

2020 ◽  
Vol 67 (1-2) ◽  
pp. 27-39 ◽  
Author(s):  
Alberto Pizarro ◽  
Carmen Díaz-Sala

Maturation-related decline of adventitious root formation is one of the major factors affecting adventitious rooting in forest tree species. We demonstrate that inhibition of polar auxin transport promoted cambium and xylem differentiation in rooting-competent hypocotyl cuttings from Pinus radiata under conditions of adventitious root formation. Treatments with bioactive gibberellins inhibited rooting while at the same time inducing both the differentiation of a continuous ring of cambium and xylem formation. Treatments with inhibitors of gibberellin biosynthesis did not affect the rooting response. The results demonstrate that xylem parenchyma and procambial cells at the xylem poles of rooting-competent hypocotyl cuttings after excision and under conditions of adventitious root induction become adventitious root meristems or xylem, depending on the directional auxin flow. Gibberellin may interact with this pathway, inducing xylem differentiation and inhibiting rooting. We conclude that modifications of auxin flow at the rooting sites, and the priming of cambial cells to differentiate into xylem during tree ageing, may be associated with the maturation-related decline of adventitious root formation.


BMC Genomics ◽  
2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Carlos Villacorta-Martín ◽  
Ana Belén Sánchez-García ◽  
Joan Villanova ◽  
Antonio Cano ◽  
Miranda van de Rhee ◽  
...  

HortScience ◽  
2020 ◽  
Vol 55 (9) ◽  
pp. 1463-1467 ◽  
Author(s):  
Benjamin E. Deloso ◽  
Anders J. Lindström ◽  
Frank A. Camacho ◽  
Thomas E. Marler

The influences of indole-3-butyric acid (IBA) concentrations of 0–30 mg·g−1 on the success and speed of adventitious root development of Zamia furfuracea L.f. and Zamia integrifolia L.f. stem cuttings were determined. Root formation success for both species was greater than 95%. The IBA concentrations did not influence the speed of root development for Z. furfuracea, but the Z. integrifolia cuttings that received IBA concentration of 3 mg·g−1 generated adventitious roots more slowly than the cuttings in the control group. The ending dry weights of the stems, leaves, and roots were not influenced by IBA concentration for either species. Our results indicated that adventitious root formation on stem cuttings of these two Zamia species is successful without horticultural application of IBA. Additional IBA studies are needed on the other 300+ cycad species, especially those that are in a threatened category.


2020 ◽  
Author(s):  
Haishan An ◽  
Jiaying Zhang ◽  
Fangjie Xu ◽  
Shuang Jiang ◽  
Xueying Zhang

Abstract Background: Propagation of cuttings is frequently used in various plant species, including blueberry, which shows special root characteristics that may hinder adventitious root (AR) formation. AR formation is influenced by various factors, and auxin is considered to play a central role; however, little is known of the related regulatory mechanisms. In this study, a comparative transcriptome analysis of green cuttings treated with or without indole-butyric acid (IBA) was performed via RNA_seq to identify candidate genes associated with IBA-induced AR formation.Results: Rooting phenotypes, especially the rooting rate, were significantly promoted by exogenous auxin in the IBA application. Blueberry AR formation was an auxin-induced process, during which adventitious root primordium initiation (rpi) began at 14 days after cutting (DAC), root primordium (rp) was developed at 21 DAC, mature AR was observed at 28 DAC and finally outgrowth from the stem occurred at 35 DAC. Higher IAA levels and lower ABA and zeatin contents might facilitate AR formation and development. A time series transcriptome analysis identified 14970 differentially expressed genes (DEGs) during AR formation, of which there were 7467 upregulated and 7503 downregulated genes. Of these, approximately 35 candidate DEGs involved in the auxin-induced pathway and AR formation were further identified, including 10 auxin respective genes (ARFs and SAURs), 13 transcription factors (LOB domain-containing protein (LBDs)), 6 auxin transporters (AUX22, LAX3/5 and PIN-like 6 (PIL6s)) and 6 rooting-associated genes (root meristem growth factor 9 (RGF9), lateral root primordium 1 (LRP1s), and dormancy-associated protein homologue 3 (DRMH3)). All these identified DEGs were highly upregulated in certain stages during AR formation, indicating their potential roles in blueberry AR formation.Conclusions: The transcriptome profiling results indicated candidate genes or major regulatory factors that influence adventitious root formation in blueberry and provided a comprehensive understanding of the rooting mechanism underlying the auxin-induced AR formation from blueberry green cuttings.


2020 ◽  
Vol 13 ◽  
pp. 194008292092059 ◽  
Author(s):  
Thomas E. Marler ◽  
Benjamin E. Deloso ◽  
Gil N. Cruz

Cycad stem cuttings will develop adventitious roots if the open wound is first treated with a sealant to protect the exposed parenchyma tissue. The commercial pruning wound sealant that is often employed for this purpose is not available in many locations. We used commonly available products as a prophylactic sealant on Cycas edentata , Cycas micronesica , and Cycas nitida cuttings to determine efficacy for sealing the wound and enabling adventitious root formation. Success was quantified after 7 months in a sand propagation substrate. Mortality was 100% for control cuttings with no wound sealant and about 60% for cuttings with candle wax as the sealant. Cuttings that received petroleum jelly, lanolin paste, modeling clay, honeycomb wax, or commercial pruning sealant exhibited 100% survival. Success in adventitious root formation ranged from 75% to 92% among the five successful prophylactic treatments and did not differ among the species. The results indicated that four of the products we evaluated were as effective as commercial pruning sealant for treating the exposed parenchyma on Cycas stem cuttings and enabling asexual propagation success. The candle wax was less effective because it was brittle and cracked to expose the stem’s parenchyma tissue.


PLoS ONE ◽  
2018 ◽  
Vol 13 (4) ◽  
pp. e0196663 ◽  
Author(s):  
Ana Belén Sánchez-García ◽  
Sergio Ibáñez ◽  
Antonio Cano ◽  
Manuel Acosta ◽  
José Manuel Pérez-Pérez

2020 ◽  
Vol 13 ◽  
pp. 194008292096690
Author(s):  
Benjamin E. Deloso ◽  
Charles J. Paulino ◽  
Thomas E. Marler

Improved horticultural practices may help to reduce demand for wild cycads threatened by unsustainable collection. We determined the influences of leaf retention with or without anti-transpirants on the success and speed of adventitious root development of Zamia furfuracea L.f. and Zamia integrifolia L.f. stem cuttings. Root formation success for both species was greater than 95%. The experimental treatments did not influence the percentage success or the speed of root development for Z. furfuracea or Z. integrifolia. The ending dry weights of the stems, leaves, and roots were also not influenced by the experimental treatments. Our results indicated that adventitious root formation on stem cuttings of these two Zamia species was highly successful with or without retained leaves, and horticultural application of transpiration-reducing products on retained leaves did not improve success. Our findings add to the growing body of evidence that show how the horticulture nursery industry can meet horticultural demands in an effort to stop wild harvesting of threatened plants. Conservation of cycads as a group would benefit from more horticulture studies such as this, especially if the research includes threatened species.


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