Concentrations Of Indolebutyric Acid Research Articles

ENRAIZAMENTO DE ESTACAS RADICULARES DE FIGUEIRA ‘ROXO DE VALINHOS’ TRATADAS COM AIB E DOIS MÉTODOS DE IMERSÃO

No caso da figueira, há carência de estudos relativos a métodos alternativos de multiplicação ao enraizamento de estacas caulinares. Assim, o objetivo do presente trabalho foi verificar a potencialidade da multiplicação da figueira por estacas radiculares. Estacas radiculares da figueira ‘Roxo de Valinhos’, foram retiradas de mudas de um ano de idade, mantidas em sacos plásticos, preenchidos com substrato estéril e ausente de nematóides. As estacas foram padronizadas com 10 cm de comprimento e diâmetro em torno de 0,3 a 0,5 cm. Após o preparo, as estacas foram imersas em diferentes concentrações de ácido indolbutírico (AIB): 0, 1000, 2000, 3000 e 4000 mg L-1, imergindo-se as estacas em diferentes métodos (totalmente e parcialmente imersas - somente uma das bases), por 10 segundos. Posteriormente, foram totalmente enterradas na posição horizontal, em caixas plásticas preenchidas com areia de textura média. As bandejas foram mantidas em ambiente de meia sombra e periodicamente umedecidas. Após 50 dias foram analisadas a porcentagem de estacas mortas, enraizadas, vivas e não enraizadas, brotadas, número médio de brotos e raízes por estaca. A concentração de 2000 mg L-1 promoveu o maior enraizamento e maior número médio de raízes por estaca, mas não foi possível a obtenção de mudas por esse método, devido a ausência de brotação.

Micropropagation of mature male pistachio Pistacia vera L.

SummaryFactors affecting the successful rapid proliferation and rooting of male pistachio (Pistacia vera L.) cv. Atlı, were studied. The most suitable type of cytokinin [6 benzyladenine (BA), kinetin (Kin), or thidiazuron (TDZ)], and the effect of eight different concentrations of BA (0.0675, 0.125, 0.25, 0.5, 1.0, 2.0, 4.0, or 8.0 mg l–1) were evaluated to optimise shoot proliferation. The auxins -naphthaleneacetic acid (NAA), indole-3-acetic acid (IAA), and indole-3-butyric acid (IBA), each at 2.0 mg l–1, or different concentrations (0.5, 1.0, 2.0, 4.0, or 8.0 mg l–1) of IBA, and the effect of explant size (1.0, 2.0, 3.0, or 4.0 cm) were assessed for root induction. The highest number of new microshoots per explant (5.64 ± 0.07) was obtained 4 weeks after culturing on Murashige and Skoog (MS) medium supplemented with 1.0 mg l–1 BA. Again, shoot length was highest in 1.0 mg l–1 BA, and decreased as the BA concentration increased. IBA was most effective in promoting root formation. The highest rooting frequency (73%) of microshoots was recorded for explants 4.0 cm in length, 4 weeks after culturing. In vitro-rooted plantlets were transferred to polyethylene pots filled with a 1:1:1 (v/v/v) mixture of soil, sand and peat.This treatment resulted in 90% survival of plantlets, which were acclimatised in a greenhouse.

In Vitro Propagation of "Jarilla" (Larrea divaricata CAV.) and Secondary Metabolite Production

An efficient protocol for the in vitro germination and propagation of Larrea divaricata CAV. (Jarilla) was established. To determine the effect of different growth regulators on the growth rates and phenol production, apical-node microshoots from in vitro germinated plantlets were incubated on the following media: 1) full-strength MS (Murashige and Skoog) salt medium with different ratios of alpha-naphthaleneacetic acid (NAA) and N(6)-benzyladenine (BA); 2) after pre-treatment with indolebutyric acid (IBA), transfer to MS medium of different inorganic salt strengths; and 3) full-strength MS salt medium with different ratios of sucrose and IBA. Successful microshoot rooting percentages were achieved by the second and third strategies, the highest being 87.5-100%. The maximum principal shoot length and node number obtained by the second strategy corresponded to the plantlets previously induced with 50 microM IBA, and grown on half- or full-strength MS salt media (7.03+/-0.93 and 9.86+/-1.07 cm, respectively) while in the third strategy the most efficient micropropagation medium was full-strength MS salt medium supplemented with 7.5 microM IBA: 3% (w/v) sucrose (7.05+/-1.08 and 7.0+/-1.51 cm, respectively). The phenol concentration was determined by analytical HPLC. The highest content of nordihydroguiaretic acid (NDGA) accumulated in microplants of L. divaricata cultivated on half-strength MS salt medium (35.90+/-3.82 mg/g DW). Reducing the MS medium salt concentration by half, in the absence of IBA, it resulted in a higher NDGA production. NDGA production was not sensitive to the variation of IBA concentration. The medium supplemented with 5% (w/v) sucrose and 2.5 microM IBA induced not only a higher NDGA production but also a higher quercetin production.

Rooting response of shoot cuttings from three peach growth habits

Current year shoot cuttings were collected in October and August from three growth habits of peach (Compact, Pillar, and Standard) and treated with one of four concentrations of indole butyric acid (0, 250, 1250, and 2500 mg L −1 IBA). Rooting response was measured after 5 weeks in the greenhouse. Little or no rooting occurred with cuttings from any growth habit that was collected in October or in August when treated with 0 and 2500 mg L −1 IBA. In August, the number of shoots that rooted was greater in cuttings from Pillar (79 and 45%) than Compact (13 and 3%) treated with 250 and 1250 mg L −1 IBA, respectively. Cuttings from Standard trees had intermediate rooting of 56 and 6% at 250 and 1250 mg L −1 IBA, respectively. Pillar trees consistently grew more roots with greater root length per cutting than the other growth habits. It is proposed that differences in rooting response among the growth habits may be associated with differences in endogenous auxin concentration that had been found in previous studies. Within peach and possibly other fruit trees, the capacity of shoot cuttings to develop adventitious roots can vary by cultivar and successful root induction with exogenous plant growth regulators may depend, in part, on endogenous hormone levels.

Adventitious root formation in shoot cuttings of Himalayan cedar (Cedrus deodara Roxb. ex Lamb.) G. Don under mist chamber conditions

Cedrus deodara is an important tree species of the Himalayan region and its clonal propagation assumes particular importance for rapid multiplication of desirable biotypes (elite). Cuttings taken from young shoots (current season’s growth) were variously treated with solutions of root inducing chemicals for 24 h, planted individually in polybags which were then placed inside a mist chamber. The experiments were conducted in four different seasons, i.e., winter, summer, monsoon and autumn. The most effective treatment was noticed for commonly used fungicide, bavistin (0.05%), that induced good rooting across seasons. Out of the two auxins tried, namely indole-3-butyric acid (IBA) and µ-naphthalene acetic acid (NAA), lower concentration (0.5mM) of IBA was more effective. Auxins were also treated in combination with phloroglucinol and coumarin, which were tried on their own as well, and the rooting success varied considerably. The monsoon season was found most suitable for taking cuttings. The results of this mist chamber based study were also compared with an earlier study carried out under a polythene tunnel, and the root induction was found similar to favour when treated cuttings were placed under mist chamber conditions.

Efeito do ácido indolbutírico e época de coleta no enraizamento de estacas semi-lenhosas do cacaueiro

O objetivo do trabalho foi verificar o efeito do ácido indolbutírico (AIB) no enraizamento de estacas do cacaueiro. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 3 x 5 x 2, envolvendo 3 clones (Cepec 2008, CCN 51 e TSH 1188), 5 concentrações de ácido indolbutírico AIB (0; 1.000; 3.000; 6.000 e 9.000 mg kg-1), duas épocas do ano (verão e inverno),, cinco repetições e 10 estacas por parcela. A avaliação do experimento foi realizada 120 dias após o plantio e analisadas as seguintes variáveis: percentagem de sobrevivência (SOB), número de brotações (NB), matéria seca das brotações (MSB), percentagem de estacas enraizadas (ENR), número de raízes (NR) e matéria seca de raízes (MSR). Os fatores época do ano e concentração de AIB apresentaram efeito significativo para as variáveis estudadas quando isolados e em interação com os clones. Os dados obtidos possibilitaram concluir que o valor médio da concentração ideal de AIB (CI) foi de 4.169 mg kg-1 e 3.985 mg kg-1 no verão e inverno, respectivamente. Verificou-se que os clones apresentam diferentes respostas em relação à CI de AIB e época do ano. De modo geral, as CIs no verão foram maiores que no inverno. Os resultados mostraram que a época de plantio e a concentração de AIB influenciaram de maneira mais expressiva na sobrevivência e enraizamento das estacas dos clones Cepec 2008 e CCN 51 e em menor intensidade no clone TSH 1188. Existe uma concentração ideal de AIB para cada um dos clones estudados.

Estaquia como processo de clonagem do bacuripari (Redhia gardneriana Miers ex Planch e Triana)

No Brasil, existem diversas fruteiras nativas com potencial de exploração comercial, especialmente na Amazônia, local de origem do bacuripari. Neste sentido, realizou-se um trabalho com o objetivo de avaliar a clonagem dessa espécie pelo processo da estaquia, mediante uso de ácido indolil-3-butírico (AIB), em condições de nebulização intermitente. O delineamento experimental foi o inteiramente casualizado, com 5 tratamentos, caracterizados pelas concentrações de AIB (0; 1.000; 3.000; 5.000 e 7.000 mg.L-1), com 4 repetições e 10 estacas por parcela. Foram avaliados na porcentagem de estacas enraizadas, o número médio de folhas e o comprimento de raízes. O uso de AIB não influenciou na porcentagem de enraizamento.

Influence of indole-3-butyric acid and propagation method on growth and development of in vitro- and ex vitro-derived lowbush blueberry plants

The effects of four indole-3-butyric acid (IBA) concentrations and two propagation methods were studied in a lowbush blueberry (Vaccinium angustifolium Ait.) clone collected from natural stands in Newfoundland and Labrador, Canada. Lowbush blueberry cultures were established in vitro from nodal explants on a modified cranberry (V. macrocarpon Ait.) tissue culture medium containing zeatin (2 μM). Blueberry plants propagated by in vitro shoot proliferation (TC) and by conventional softwood cuttings (SC) were evaluated for growth and morphology. Significant interactions for morphological characteristics were observed among the treatments. The IBA concentration had an effect on morphology of propagated plants, increasing the concentration of IBA increased stem length and leaves per stem across propagation methods. Stems per plant increased with IBA concentration up to 20 μM in SC plants, but not in TC plants. Plant vigor was affected by neither IBA concentration nor propagation method. The TC plants produced longer and more stems with more leaves per stem than the conventional cuttings. In vitro culture on zeatin-containing nutrient medium apparently induces the juvenile branching characteristics that favored enhanced vegetative growth with more stems and leaf production. It is suggested that IBA may serve as a physiologically active form of auxin in contributing to increased stem and leaf production in lowbush blueberry SC plants but not in TC plants.

Effects of carbon sources and auxins on in vitro propagation of banana

The effects of carbon sources (sucrose, glucose, fructose and mannitol) and auxins [indolebutyric acid (IBA) and α-naphthaleneacetic acid (NAA)] on in vitro propagation of banana (Musa spp. AAA) were studied. Over all carbon sources tested, sucrose induced highest frequency of shoot proliferation. Optimal shoot proliferation rates were achieved on the Murashige and Skoog (MS) medium supplemented with sucrose and glucose combination (1:1) at the concentration of 30 g dm−3. Similarly, higher frequency of root induction was obtained at IBA and NAA combination (1:1; concentration of 2 mg dm−3) than at other concentrations of IBA or NAA alone or their combinations.

Embryo germination and proliferation in vitro of Juglans regia L.

This paper presents the optimal culture conditions for the in vitro embryo germination and proliferation of Juglans regia L. rootstock cv. Peralta, selected by the IMIDA fruticulture team. J. regia L. rootstock cv. Peralta is characterised by its resistance to salinity, lime and by its vigour. The first experiment determined the best culture medium for in vitro embryo germination. The Murashige and Skoog medium (MS; Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco tissues cultures. Physiol. Plant. 15, 473–497), the medium developed by our team for walnut (NGE), the Lloyd and McCown medium (WPM; Lloyd, G., McCown, B., 1981. Commercially feasible micropropagation of mountain laurel, Kalmia latifolia, by the use of shoot tip culture. Proc. Plant Prop. Soc. 30, 421–427) and that of Driver and Kuniyuki (DKW; Driver, J.A., Kuniyuki, A.M., 1984. In vitro propagation of Paradox walnut rootstock. HortScience 19 (4), 507–509), were compared, all without growth regulators. The best germination percentage was obtained in WPM (81%) with significant differences between the different media. In the second experiment, the optimal benzylaminopurine and indole butyric acid concentrations were determined for the proliferation stage of the explants obtained in the first experiment. The proliferation rates obtained varied from 0 in the medium without cytokinins to 6 in the medium with 0.5 mg l −1 BAP. The cluster proliferation quality and other parameters studied indicate that the optimal treatment was 0.5 mg l −1 BAP.

Ácido indolbutírico no enraizamento de estacas semilenhosas do porta-enxerto de videira 'VR043-43' (Vitis vinifera x Vitis rotundifolia)

Este trabalho teve como objetivo avaliar diferentes concentrações de ácido indolbutírico (AIB) no enraizamento de estacas semilenhosas do porta-enxerto de videira 'VR043-43' (Vitis vinifera x Vitis rotundifolia). O experimento foi realizado na Universidade Federal do Paraná, Curitiba-PR, no período de dezembro de 2004 a janeiro de 2005. As concentrações de AIB testadas foram 0; 1.000; 2.000 e 3.000 mg L-1, sendo a base das estacas imersas nas soluções dos reguladores vegetais, durante dez segundos. Após 40 dias em câmara de nebulização, as estacas foram avaliadas. As estacas com maior porcentagem de enraizamento foram aquelas que não receberam tratamento com AIB (92,5%). A porcentagem de estacas mortas aumentou com as concentrações de AIB, e a porcentagem de retenção foliar diminuiu. Houve incremento do número médio de raízes primárias por estacas com as maiores concentrações de AIB, porém as matérias fresca e seca das raízes não diferiram significativamente entre os tratamentos. Conclui-se que o AIB não é necessário para o enraizamento de estacas semilenhosas do porta-enxerto 'VR043-43'.

Indol-butyric acid levels on cashew cloning by air-layering process

A study was conducted to determine the possibility of cashew (Anacardium occidentale) cloning by air-layering and influence of IBA (indol-butyric acid) on this process. It was adopted a completely randomized design with 4 treatments, 10 air layers each and 4 replications, reaching 160 air layers. The IBA levels on the treatments were, as follow: 0, 1000, 3000 and 5000 mg.kg-1. It was evaluated: survival, callus and rooting percentage, average number and length of roots. The highest survival rate (67.5%) was registered with no growth regulator and IBA at 1000 mg.kg-1, while the best rooting percentage (82%) referred to 1000 mg.kg-1. In spite of average number and length of roots, the highest results were observed with IBA at 5000 mg.kg-1. IBA concentrations had no influence on cashew air-layering formation.

Direct organogenesis and plantlet regeneration from mature zygotic embryos of masson pine (Pinus massoniana L.)

Mature zygotic embryos of masson pine were cultured as initial explants to investigate the process of direct organogenesis. Adventitious buds were initiated on DCR medium (Douglas-fir cotyledon revised medium) supplemented with 0.5 mg l−1 N6-benzyladenine (BA) and 0.05 mg l−1 indolebutyric acid (IBA) or α-naphthaleneacetic acid (NAA). The highest induction frequency of adventitious buds was 99.3%. Subsequent transfer of buds to medium with lower concentrations of plant growth regulators in time was necessary for differentation of high quality adventitious buds. After culturing on elongating medium, in which the proportion of cytokinins to auxins was reduced, shoots higher than 2 cm were transferred for root induction to GD medium with half of the concentration of macro-salts (½ GD) and with 2 mg l−1 IBA and 0.05 mg l−1 BA. The average root frequency was over 70%. After adventitious roots had appeared, the shoots were transferred to ½ GD medium with a lower concentration of IBA (0.2 mg l−1) for further root development.

Changes in Concentrations of Cytokinins (CKs) in Root and Axillary Bud Tissue of Miniature Rose Suggest that Local CK Biosynthesis and Zeatin-Type CKs Play Important Roles in Axillary Bud Growth

Involvement of cytokinins (CKs) in axillary bud growth of miniature rose was studied. Variation in root formation and axillary bud growth was induced by two indole 3-butyric acid (IBA) pretreatments in two cutting sizes. At six physiological developmental stages around the onset of axillary bud growth, concentrations of CKs were determined in both root and axillary bud tissue by liquid chromatography combined with electrospray tandem mass spectrometry (LC-ESP-MS/MS). Chronological early onset of axillary bud growth occurred in long cuttings pretreated at low IBA concentration, whereas physiological early root formation was associated with long cuttings and high IBA concentration. The CKs zeatin (Z), isopentenyl adenine (iP), zeatin riboside (ZR), dihydrozeatin riboside (DHZR), isopentenyl adenosine (iPA), zeatin O-glucoside (ZOG), zeatin riboside O-glucoside (ZROG), zeatin riboside 5′-monophosphate (ZRMP), and isopentenyl adenosine 5′-monophosphate (iPAMP) were detected. Concentrations of CKs in axillary bud tissue far exceeded those in root tissue. Indole 3-butyric acid pretreatment influenced the concentration of CKs in axillary bud tissue more than did cutting size, whereas pretreatments only slightly affected CKs in root tissue. The dominant CKs found were iPAMP and ZR. An early and large increase in iPAMP indicated rapid CK biosynthesis in rootless cuttings, suggesting that green parts, including the axillary bud, can synthesize CKs. At the onset of axillary bud growth an increase in concentration of Z, ZR, ZRMP, ZOG, and ZROG was largely coincident with a decrease in iPAMP, iPA, iP, and DHZR. After the onset of axillary bud growth, CK content largely decreased. These results strongly indicate a positive role for CKs in axillary bud growth, and presumably ZRMP, ZR, and Z are active in miniature rose.

Analysis of indole-3-butyric acid-induced adventitious root formation on Arabidopsis stem segments

Root induction by auxins is still not well understood at the molecular level. In this study a system has been devised which distinguishes between the two active auxins indole-3-butyric acid (IBA) and indole-3-acetic acid (IAA). IBA, but not IAA, efficiently induced adventitious rooting in Arabidopsis stem segments at a concentration of 10 microM. In wild-type plants, roots formed exclusively out of calli at the basal end of the segments. Root formation was inhibited by 10 microM 3,4,5-triiodobenzoic acid (TIBA), an inhibitor of polar auxin transport. At intermediate IBA concentrations (3-10 microM), root induction was less efficient in trp1, a tryptophan auxotroph of Arabidopsis with a bushy phenotype but no demonstrable reduction in IAA levels. By contrast, two mutants of Arabidopsis with measurably higher levels of IAA (trp2, amt1) show root induction characteristics very similar to the wild type. Using differential display, transcripts specific to the rooting process were identified by devising a protocol that distinguished between callus production only and callus production followed by root initiation. One fragment was identical to the sequence of a putative regulatory subunit B of protein phosphatase 2A. It is suggested that adventitious rooting in Arabidopsis stem segments is due to an interaction between endogenous IAA and exogenous IBA. In stem explants, residual endogenous IAA is transported to the basal end of each segment, thereby inducing root formation. In stem segments in which the polar auxin transport is inhibited by TIBA, root formation does not occur.

Factors affecting tissue culture of Damask rose ( Rosa damascena Mill.)

The present study was conducted to evaluate the regeneration ability of Damask rose. Single-node explants were surface sterilised with 10% chlorox for 15 min and cultured on Murashige and Skoog (MS) medium supplemented with various concentrations of N 6-benzyladenine (BA) or kinetin (Kin) separately or in combination with different concentrations of indole-3-butyric acid (IBA). Combination of 2.5–3 mg/l BA and 0.1 mg/l IBA was the most suitable treatment for proliferation. In vitro derived shoots were subcultured four times on the fresh medium within a 4-week period. Other treatments such as explant orientation (horizontal, vertical and oblique) and explant wounding were also examined but did not affect shoot multiplication rate significantly. Several experiments were carried out to stimulate in vitro rooting of Damask rose. Application of different media such as MS, 1/2 MS, 1/3 MS and 1/4 MS with different concentrations of indole-3-acetic acid (IAA), IBA and naphthaleneacetic acid (NAA) did not produce satisfactory results. Quick-dip method using sterilised 0–2000 mg/l IAA, IBA and NAA solutions was also studied. Other treatments such as using various concentrations of abscisic acid (ABA) in combination with various concentrations of IAA, IBA and NAA, and using various concentrations of sucrose and agar did not produce any roots. The best treatment for rooting of shoots was 2.5 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D) for 2 weeks in MS medium and then transferring the explants to MS medium without any growth regulator. Plantlets were acclimatised in a soil mixture consisting of peat moss and sand 1:1 (v/v) and successfully transferred to the greenhouse after 3 weeks.

Micropropagation of a Cold Hardy Selection of Cercis canadensis L. Through Single-Node Culture

Abstract A cold hardy eastern redbud (Cercis canadensis L., TS 0092) was propagated using single-node micropropagation. In vitro shoot cultures were initiated from rapidly growing shoot tips of a mature tree. The effects of basal media and plant growth regulators on proliferation were investigated. Maximum proliferation rate was obtained from all three tested media, Murashige and Skoog (MS), Woody Plant Medium (WPM), and Driver-Kuniyuki walnut (DKW), supplemented with 0.5 μM thidiazuron (TDZ). Shoots produced on WPM medium appeared stressed showing yellowish and thin leaves compared to those on MS and DKW media. Shoots were in vitro rooted in auxin-free half strength WPM medium after being pulsed for 1 to 16 days in half strength WPM medium with 12.5 to 100 μM indole-3-butyric acid (IBA). In vitro rooting rate was influenced by IBA concentration, pulsing time, and shoot sources (media in which shoots were produced). Shoots produced in DKW medium rooted best after being pulsed in 25 to 100 μM IBA for 8 days although root numbers were similar among treatments. Direct ex vitro rooting was achieved by quick-dipping the microshoots in 10 μM IBA or NAA solutions and inserting them in Jiffy Mix potting medium.

Mutations in Arabidopsis acyl‐CoA oxidase genes reveal distinct and overlapping roles in β‐oxidation

Indole-3-butyric acid (IBA) is an endogenous auxin used to enhance rooting during propagation. To better understand the role of IBA, we isolated Arabidopsis IBA-response (ibr) mutants that display enhanced root elongation on inhibitory IBA concentrations but maintain wild-type responses to indole-3-acetic acid, the principle active auxin. A subset of ibr mutants remains sensitive to the stimulatory effects of IBA on lateral root initiation. These mutants are not sucrose dependent during early seedling development, indicating that peroxisomal beta-oxidation of seed storage fatty acids is occurring. We used positional cloning to determine that one mutant is defective in ACX1 and two are defective in ACX3, two of the six Arabidopsis fatty acyl-CoA oxidase (ACX) genes. Characterization of T-DNA insertion mutants defective in the other ACX genes revealed reduced IBA responses in a third gene, ACX4. Activity assays demonstrated that mutants defective in ACX1, ACX3, or ACX4 have reduced fatty acyl-CoA oxidase activity on specific substrates. Moreover, acx1 acx2 double mutants display enhanced IBA resistance and are sucrose dependent during seedling development, whereas acx1 acx3 and acx1 acx5 double mutants display enhanced IBA resistance but remain sucrose independent. The inability of ACX1, ACX3, and ACX4 to fully compensate for one another in IBA-mediated root elongation inhibition and the ability of ACX2 and ACX5 to contribute to IBA response suggests that IBA-response defects in acx mutants may reflect indirect blocks in peroxisomal metabolism and IBA beta-oxidation, rather than direct enzymatic activity of ACX isozymes on IBA-CoA.

Influence of some external factors on the rooting of GF677, peach and nectarine shoot hardwood cuttings

The influence of some external factors [cultivar, indole-butyric acid (IBA) concentration, IBA dipping of shoot tip and base, preheating of cuttings, collecting date, time of cutting collection, mother tree age, cultivar, length of and diameter of cutting] on rooting of peach–nectarine hardwood shoots in the field were examined. It was found that the best IBA concentration for rooting differed among peach cultivars. Rooting of cuttings whose bases only were immersed in IBA solution was higher than those that had both base and tip immersed. In addition, a higher percentage of rooting shoots was achieved with preheating of cuttings before planting. The best length for cuttings varied between cultivars and the best diameter was 10–13 mm. Cuttings collected between 25 October and 13 November (1997 and 1998) showed the highest percentage of rooting shoots. There was also a higher percentage of rooting GF677 hardwood shoot cuttings collected from 7-year-old mother trees compared with those collected from 1-year-old mother trees.

Influence of propagation temperature, photosynthetic photon flux density, auxin treatment and cutting position on root formation, axillary bud growth and shoot development in Schlumbergera ‘Russian Dancer’

SummaryThe effects of propagation soil temperature and photosynthetic photon flux density (PPFD), indole-3-butyric acid (IBA) concentration, and cutting position on root formation, axillary bud growth, and further growth were investigated in Schlumbergera ‘Russian Dancer’. Temperatures between 21.3ºC and 24.7ºC were optimal for root formation, whereas increasing temperature promoted axillary bud growth (onset of new phylloclade growth). At temperatures below 24.7ºC, root formation and axillary bud growth occurred more or less simultaneously, whereas at higher temperatures axillary bud growth occurred before roots were visible. Temperature also affected the number of phylloclades on the second and third levels of stem segments produced after propagation. On increasing PPFD from 46 to 72 µmol m–2 s–1 during propagation, time to axillary bud growth was reduced by 15%, and more phylloclades were produced at high PPFD combined with high temperature. Rooting ability and axillary bud growth were affected by cutting position on the stock plants, indicating the presence of topophysis in Schlumbergera. Time to visible roots and number of new phylloclades decreased basipetally with the original position of the cutting by approximately 25%, whereas time to axillary bud growth increased basipetally by 30%. Survival of cuttings receiving IBA at 10–5–10–3 M was superior. IBA at 10–3 M resulted in the shortest time to visible rooting. At increasing IBA concentration, time to axillary bud growth gradually increased and fewer phylloclades were produced. Concentrations of 10–2 and 10–1 M IBA had negative effects on all measured characters. The results are discussed in relation to possible roles of auxins and cytokinins.