Effect of Phenological Stage and Rooting Enhancers on Physiological Parameters in Stem Cuttings in the Process of Rhizogenesis of Rosa × alba ‘Maiden’s Blush’

Abstract

Once-blooming roses belong to difficult-to-root. One-bud leafy cuttings have limited storage capacity, due to the small size of the stem, and are exposed to prolonged stress conditions. The objective of this study was to examine if the treatment of the cuttings of Rosa × alba ‘Maiden’s Blush’ with plant origin preparations as rooting enhancers may increase their rooting percentage, chlorophyll a/b, and proteins concentration in leaves. The cuttings were prepared from shoots in four phenological stages: flower buds closed, flowers open, immediately after petal shedding, and 7–14 days after petal fall. The following were used: 0.4% indole butyric acid (Ukorzeniacz Aaqua), 0.2% naphthalene acetic acid (Ukorzeniacz Baqua), Bio Rhizotonic; Root Juice™, and Bio Roots. Controls included untreated cuttings. The highest rooting percentage was obtained after two treatments with 0.6% Bio Rhizotonic (81.5%), compared to the control (55.0%), using cuttings from shoots with flower buds closed, but the rooting enhancers did not show any unequivocal impact on rooting percentage in cuttings of all phenological stages or affected improvement this feature in cuttings harvested 7–14 after shedding petals with low root ability. However, the action of plant preparations affected positively higher soluble proteins and chlorophyll content. The plant-origin preparations can be used as alternatives to chemicals in nursery production.

The Role of Plant Origin Preparations and Phenological Stage in Anatomy Structure Changes in the Rhizogenesis of Rosa “Hurdal”

“…These results have certainly indicated the possibility for use of these preparations in the rooting of “Hurdal” rose cuttings and may be recommended as alternative preparations of natural origin in the ecological propagation (91/414/EEC, 2009/128/WE; OJEU), compared to the classic synthetic stimulators. Plant origin preparations could positively influence changes in the condition of cuttings and the content of bioactive components in roses (Monder and Pacholczak, 2018 , 2019 ; Monder et al, 2020 ) due to supplementation with nutritive substances or unknown rooting cofactors and IAA-like substances present in the bio preparations (Nardi et al, 2015 ; Oosten et al, 2017 ). Most bio preparations of plant origin contain different substances similar to auxins in various concentrations (Crouch and Van Staden, 1993 ; Thorsen et al, 2010 ; Pacholczak et al, 2016 ).…”

“…Various rooting enhancers, including plant hormones (Pihlajaniemi et al, 2005 ; Ginova et al, 2012 ) and biostimulants (Monder and Pacholczak, 2019 ; Monder et al, 2020 ) were used to encourage the natural ability of cuttings to undergo rhizogenesis and also to improve the quality and physiological parameters of rooted cuttings. Some of the preparations important in nursery production contained indole butyric acid (IBA) or naphthalene acetic acid (NAA) as standard rooting enhancers in the procedure of rooting cuttings (Hartmann et al, 2011 ).…”

“…The content of humic substances could lead to higher nutrient content in the tissues of the cuttings as well as positive metabolic changes (Nardi et al, 2015 ). The above preparations affected the content of chlorophyll a, b, carotenoids, soluble proteins (Monder et al, 2020 ), and carbohydrates in roses (Monder and Pacholczak, 2018 ) and can indirectly influence the effectiveness of rhizogenesis.…”

The Pivotal Role of Phenological Stage Enhanced by Plant Origin Preparations in the Process of Rhizogenesis of <em>Rosa</em> ‘Hurdal’ Stem Cuttings

“…In this experiment, none of the rooting enhancers changed this result, and neither did the use of two rooting substrates (Figure 3). In research on the 'Maiden's Blush' rose, the rooting enhancers, including plant origin preparations, did not show any unambiguous impact on rooting percentage in cuttings or affect the low natural rooting ability in shoots harvested for cuttings 7-14 days after shedding petals [31].…”

“…The hypothesis was that plant origin preparations could enhance rooting processes, inhibiting chlorophyll degradation and postponing leaf senescence and at the same time increasing the quality of cuttings. In previous research we proved the key roles of the phenological stage of shoots harvested for cuttings [6,[29][30][31] and of the rooting substrate [8] in the rhizogenesis of this taxon. In this work, the results were analysed considering four phenological stages of shoots and two rooting substrates.…”