“…Accordingly, apical cuttings of the cultivars ‘Pink Song’, ‘Orange Beauty’, ‘Gummack’ showed the highest rooting percentage (Park et al 2011 ). Otiende et al ( 2017 ) studied position effects on rooting of Rosa hybrida ‘Natal briar’ and ‘Rosa progress’ and found, that number, length and dry mass of ARs of increased along the bottom, middle and top position of vertical, 1.5 m long shoots. Fig.…”
Section: Introductionmentioning
confidence: 99%
“…Considering these relationships, the present study aimed to elucidate the influence of nodal position of rose cuttings on auxin and CK homeostasis and its potential role in position-affected AR formation. Based on the findings of Otiende et al ( 2017 ), we investigated whether the two cultivars ‘Natal Briar’ and ‘Rosa Progress’ can be characterized by a similar acropetal shift of auxin–cytokinin patterns during the early rooting period. Top and bottom cuttings of both cultivars were planted and concentrations of IAA and diverse CKs were monitored in the stem base as the zone of AR regeneration and in the bud region as the zone of bud outgrowth.…”
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.
“…Accordingly, apical cuttings of the cultivars ‘Pink Song’, ‘Orange Beauty’, ‘Gummack’ showed the highest rooting percentage (Park et al 2011 ). Otiende et al ( 2017 ) studied position effects on rooting of Rosa hybrida ‘Natal briar’ and ‘Rosa progress’ and found, that number, length and dry mass of ARs of increased along the bottom, middle and top position of vertical, 1.5 m long shoots. Fig.…”
Section: Introductionmentioning
confidence: 99%
“…Considering these relationships, the present study aimed to elucidate the influence of nodal position of rose cuttings on auxin and CK homeostasis and its potential role in position-affected AR formation. Based on the findings of Otiende et al ( 2017 ), we investigated whether the two cultivars ‘Natal Briar’ and ‘Rosa Progress’ can be characterized by a similar acropetal shift of auxin–cytokinin patterns during the early rooting period. Top and bottom cuttings of both cultivars were planted and concentrations of IAA and diverse CKs were monitored in the stem base as the zone of AR regeneration and in the bud region as the zone of bud outgrowth.…”
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.
“…The content of soluble sugars on the 2nd day of root induction phase was positively correlated with rooting e ciency, and on the 7th with all studied rooting characteristics. Involvement of carbohydrates, particularly soluble sugars, in adventitious rooting process is usually related to their role as a carbon and energy source (Megre et al 2011, Otiende et al 2017. In this respect TSS can be considered the most impactful biomarker in studied species, and factors stimulating TSS synthesis could potentially enhance its rooting ability.…”
Pulsatilla turczaninovii is an important medicinal plant and a material also appreciated by gardeners for its high ornamental value. In this study we assessed the efficiency of reproduction under in vitro conditions of this important representative of the world flora. First, the germination percentage and the following plant development during three growing seasons were assessed, then we tested the possibilities of multiplication by in vitro culture methods. Our study provided new insight on biochemical background of generating adventitious roots in Pulsatilla considered difficult-to-rooting. The germination percentage of studied population reached about 55%. The highest multiplication coefficient of micro-rosettes in tissue culture, amounting to 5.17, was achieved using modified MS medium supplemented with 2.5 mg L-1 2iP and 1 mg L-1 IAA. We proved that in comparison with standard auxin-supplemented rooting medium, the treatment with addition of 1.0 mg L-1 ethylene precursor ACC elevated adventitious rooting by about 20%. The biochemical analyses revealed that total content of soluble sugars was the most impactful biomarker of adventitious rhizogenesis in studied species. Concentration of sugars was positively correlated with rooting efficiency, while the level of phenolic compounds was positively correlated with the root length and their number regenerated per single rosette.
“…The content of soluble sugars on the second day of the root induction phase was positively correlated with rooting efficiency, and on the seventh day with all the examined rooting characteristics. Involvement of carbohydrates, particularly soluble sugars, in the rooting process is related to their role as a carbon and energy source (Megre et al 2011;Otiende et al 2017). In this respect, we consider TSS to be the best biomarker in studied species, and factors stimulating TSS synthesis could potentially increase rooting ability.…”
Pulsatilla turczaninovii is an important medicinal plant, valued for high ornamental value of melliferous flowers. We assessed the efficiency of reproduction under in vitro conditions and the ex situ growth capacity of this important representative of the world flora. The seed germination percentage was assessed, followed by determination of micropropagation rate and rooting efficiency. Then, the possibility of plant development in three consecutive growing seasons was assessed. The in vitro germination percentage was approximately 55%. The highest multiplication coefficient, amounting to 5.17, was obtained on modified MS medium supplemented with 2.5 mg L−1 2iP and 1.0 mg L−1 IAA. Our study provided unique insight on biochemical background of root regeneration in P. turczaninovii. In comparison with standard auxin-supplemented rooting medium, the treatment with 1.0 mg L−1 level of ethylene precursor ACC elevated rooting by about 20%. The total content of soluble sugars was proved to be biomarker of rhizogenesis in the studied species. Their concentration was positively correlated with rooting efficiency, while a level of phenolic was positively correlated with the length of regenerated roots, and their number per rosette. The cultivation of the acclimatized material was successfully carried out and was evaluated over three subsequent years. In the third year of cultivation, the plants entered the stage of generative development and most of them bloomed profusely.
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