IBA-treated Cuttings Research Articles

Enhancing dragon fruit [Hylocereus undatus (Haw.) Britt and Rose] propagation with indole-3-butyric acid (IBA) and cutting techniques

ABSTRACT This study evaluated dragon fruit propagation using various concentrations of indole-3-butyric acid (IBA) and cutting lengths over two seasons (March and July 2022). Results revealed that 30 cm cuttings treated with 1000 ppm IBA had the earliest shoot emergence (14.8 days in March) and the highest shoot counts (3.2 per cutting in March, 2.8 in July). The same treatment achieved maximum shoot fresh (222.7 g) and dry weights (66.8 g). Root parameters improved significantly, with a mean root count of 26.8 roots per cutting in 30 cm cuttings and maximum root fresh (6.8 g) and dry weights (1.9 g), along with a root length of 24.8 cm. Chlorophyll content reached a maximum of 6.4 mg/g in IBA-treated cuttings. Higher IAA (0.5 µg/ml) and GA3 (13.5 µg/ml) levels were observed in treated cuttings, alongside increased peroxidase activity and reduced IAA oxidase levels. Elevated phenols (1.3 mg/g FW) and carbohydrates (41.9%) also supported rooting. The highest cutting success rate (93.7%) was observed in 1000 ppm IBA-treated 30 cm cuttings in March, demonstrating that this treatment effectively promotes rooting and shooting growth in dragon fruit.

Indole acetic-producing bacteria promote the root development of Acacia mearnsii cuttings

ABSTRACT Black wattle (Acacia mearnsii) is one of the most important commercial tree species in southern Brazil, where it is planted for multiple uses, such as cellulose pulp production and tannin extraction. Recently, forest companies have been directing their efforts towards vegetative propagation to improve the productivity of black-wattle plantations. However, rooting rates of this species are low, even when treated with the synthetic auxin indole-3-butyric acid (IBA). Thus, rooting black-wattle cuttings is still considered a bottleneck for industry development. On the other hand, it is known that inoculating cuttings with indole acetic acid (IAA)-producing bacteria can be an efficient method for increasing vegetative propagation. This study investigated the potential of two bacterial strains to promote root development in black wattle. The strains SEMIA 436 and 439 (Agrobacterium radiobacter), previously isolated from the common bean and detected as high-IAA producers, were also evaluated in relation to their colonisation capacity in seedling roots. Results showed that inoculation with both strains increased rooting rates by 20−30% compared with non-treated and IBA-treated cuttings. Moreover, inoculation increased root dry mass, length and volume. Strain SEMIA 436 demonstrated higher colonisation capacity.

Stock plant etiolation reduces rooting of sub-terminal olive cuttings by reducing total sugars, IAA, indole/phenol ratio, and IAA/GA ratio

Adventitious root formation is the key to successful propagation of olives through cuttings. Etiolation, as an eco-friendly practice, can modulate the plant’s endogenous phytohormone, which plays an important role in stimulation of rooting of cuttings. Therefore, this study was aimed to investigate the effect of etiolation on the rooting behavior of both ‘Manzanillo’ and ‘Picual’ olive cuttings (terminal and sub-terminal) treated with IBA (0, 4000 ppm). The results indicated that sub-terminal cuttings in both cultivars were more effective in olive propagation than terminal cuttings as they recorded increased leaves number, C/N ratio, total carbohydrates, total indoles, IAA, IAA/GA ratio, and total phenols. Etiolation of both olive cultivars for both terminal and sub-terminal cuttings significantly decreased rooting percent, roots number, IAA, and IAA/GA ratio; while, it increased GA and GA/IAA. Moreover, etiolation decreased total sugars, IAA, IAA/GA ratio, and indole/phenol ratio in both sub-terminal cuttings. Terminal ‘Manzanillo’ cuttings achieved a higher rooting percent than terminal ‘Picual’ cuttings by 5.83% and 202.2% as mean of both seasons for untreated and IBA-treated cuttings, which was accompanied by significant increase in vascular bundle%, total phenol, phenol/indole ratio, IAA, and IAA/GA ratio by 21.48%, 49.2%, 44.72%, 12.9%, and 22.9%, respectively. Also, terminal ‘Manzanillo’ cuttings recorded lower GA by 7.98% and GA/IAA ratio by 18.21% and pith by 6.13% than terminal ‘Picual’ cuttings. This study proved that olive plants need exposure to full sunlight to propagate easily by cuttings since etiolation had negative effects on IBA-treated cuttings.

Orites myrtoidea (Proteaceae): efecto de estratificación fría en germinación de semillas y ácido indol butírico en enraizamiento de estacas

Se estudio la propagacion por semillas y por estacas de Orites myrtoidea (“Radal enano”), un arbusto con potencial ornamental de la familia Proteaceae, nativo de Chile y Argentina. A partir de material recolectado en otono en la cordillera de la comuna de Pinto, Region de Nuble, se evaluo el efecto en la germinacion de semillas de 4 niveles de estratificacion humeda a 10° C (0, 7, 14 y 21 dias), mas uno de acido giberelico (250 ppm) como control positivo, y el porcentaje y grado de enraizamiento de estacas con 5 niveles de inmersion rapida en solucion de Acido Indol Butirico (AIB) (0, 1.000, 2.000, 3.000 y 4.000 ppm) y un nivel de AIB en formulacion en polvo (1.500 ppm). Los mayores porcentajes de germinacion se obtuvieron con estratificacion por 21 dias y con inmersion en acido giberelico, 80 y 92%, respectivamente. En la propagacion vegetativa el porcentaje de enraizamiento supero el 90% en todos los tratamientos, sin embargo, todas las estacas tratadas con AIB presentaron un enraizamiento moderado a abundante, superior al control, en el cual se obtuvo un enraizamiento escaso a moderado

Exploring Vegetative Propagation Techniques for the Threatened Pteroceltis tatarinowii Maxim Using Stem Cuttings

Pteroceltis tatarinowii Maxim, the only species of the genus Pteroceltis (family Ulmaceae), is an endemic rare tree species in China. This study was performed to explore vegetative propagation techniques for P. tatarinowii using stem cuttings. First, the effects of exogenous indole-3-butyric acid (IBA) and cutting positions on rooting performance were investigated to screen the appropriate exogenous auxin treatment and to determine the proper cuttings type. The results showed that the control cuttings pretreated with no exogenous IBA, irrespective of whether the stem cuttings were terminal, middle, or basal, rooted in a manner significantly inferior to that of cuttings pretreated with IBA. Their rooting percentage was less than 50%. Among the IBA-treated cuttings, the middle cuttings pretreated with 1000 mg·L−1 IBA rooted best, with the shortest number of days until rooting emergence (20 days), the highest rooting percentage (84.0%), the lowest mortality rate (4.0%), the greatest root number (average of 6.7 per cutting), and the longest roots per cutting (44.4 cm per cutting). Terminal cuttings pretreated with 1000 mg·L−1 IBA acquired satisfactory rooting traits and had the same shortest rooting duration (20 days) and the following parameters: rooting, 70.7%; mortality, 10.7%; average roots per cutting, 5.2; and longest root, 29.1 cm. To further determine the optimum cutting propagation time for this plant, a second experiment was performed and the cuttings were collected beginning in early June, when the growth of the current season was feasible for harvesting cuttings. Stem cuttings collected in late June and middle July had significantly higher rooting percentages (≥80%) compared with those collected in early June (66.7%). The other three rooting parameters were not significantly affected by the collection date. However, according to the overall rooting traits, the cuttings collected in both late June and middle July remarkably outperformed those collected in early June regarding the number of roots and the total root length per cutting. The initial nutrient reserves in the cuttings were also determined. A significant difference in the soluble carbohydrate level was found among collection times, but the nitrogen level in the cuttings was similar. The study revealed that stem cutting propagation of P. tatarinowii was achievable, and it was best achieved with cuttings collected from the terminal and middle positions of the branches of the current season from late June to middle July and treated with 1000 mg·L−1 IBA using the quick dip method.

Effect of Paclobutrazol on Adventitious Root Formation of IBA-Treated Cuttings of ‘Zard’ and ‘Dakal’ Olive ( Olea europaea L.) Cultivars

Olive cuttings are difficult to propagate. They root well using synthetic auxin, indole-3-butyric acid (IBA). To evaluate the rooting and viability of olive semi-hardwood cuttings of ‘Dakal’ and ‘Zard’ cultivars in response to application of growth retardant, paclobutrazol (PBZ), and interaction of IBA and PBZ, a greenhouse experiment was conducted in 2012. Cuttings were dipped for 30 minutes in PBZ (0, 1000, 2000, and 4000 mg.L -1 ) and for 50 seconds inIBA (2000 mg.L -1 ) solutions, respectively and then planted in a sandy bed of propagation under automatic mist system with 95% humidity and 20±5 o C base temperature. Results showed that cutting viability, percentages of rooted, callused and rooted plus callused cuttings and root growth parameters were higher in ‘Dakal’ cultivar than ‘Zard’ cultivar. The 2000 mg.L -1 PBZ treated cuttings had a higher cutting viability, rooting percentage, number of branches per cutting, shoot length, number of roots per cutting, root length and root fresh and dry weights than the control. It appears that the rooting of ‘Dakal’ cultivar can be substantially improved by the treatment of PBZ (included IBA).

The effect of IBA on anatomical changes and antioxidant enzyme activity during the in vitro rooting of smoke tree (Cotinus coggygria Scop.)

Induction of adventitious roots is crucial for the in vitro micropropagation of woody species. In this study the histological and biochemical aspects of the adventitious root formation in microcuttings of smoke tree were evaluated. Smoke tree shoots grown on Murashige and Skoog's (1962) medium with 1mgdm−3 N6-benzyladenine (BA) and 0.1mgdm−3 1-naphtaleneacetic acid (NAA) were transferred onto a rooting medium with or without 20mgdm−3 indole-3-butyric acid (IBA) and sampled at various intervals for histological and biochemical analyses of the rooting process. First cell divisions were observed on the first day of culture in the area of primary bark identifiable root primordia with an oval shape and several cell layers were present at Day 3 in cuttings on both media. Roots with organized tissue were observed 9days after the root induction on the medium with IBA; In shoots rooted on medium with IBA, the induction phase corresponded to a transient increase in the oxidase indole-3-acetic acid (IAAO) activity and levels of endogenous indole-3-acetic acid (IAA) and hydrogen peroxide (H2O2) coincidental with a reduction in the peroxidase (POX) and polyphenol oxidase (PPO) activity and the polyphenoloacids contents. An increase the PPO and POX activity, accompanied by a low activity of IAAO during phases of root development and elongation resulted in a reduction of the endogenous auxin and H2O2 contents in the IBA-treated cuttings.

Effect of Indole-3-Butyric Acid on Clonal Propagation of Mulberry (Morus alba L.) Stem Cuttings: Rooting and Associated Biochemical Changes

Fuel wood scarcity in the Himalayan region is an established fact and mulberry (Morus alba L.) tree has a great potential in fuel and energy production. This study determines the role of indole-3-butyric acid (IBA) for rapid clonal propagation of mulberry for higher biomass and large-scale production; and examines the associated biochemical changes during rooting. The non-treated (control) and treated (1000, 2000 and 3000 IBA mg L−1) soft stem cuttings were cultured in mist chamber. After 50 days the rooting percentage, root number and root length were found to be higher in IBA-treated cuttings than in the non-treated ones. The rooting zone of IBA-treated and untreated cuttings were sampled at day 0 (prior to the culture in mist chamber), 15, 30, and 45 for estimation of total soluble indole content, peroxidase (POX), indole acetic acid oxidase (IAA-oxidase) and total soluble sugar (TSS). The total soluble indole, POX and IAA-oxidase were enhanced due to IBA. POX increased from day zero to day 45 of culture. IAA-oxidase kept increasing for 30 days and thereafter declined markedly. IBA initially increased TSS, which later decreased with passage of time till the 30th day both in IBA-treated and control cuttings. Thereafter, TSS content exhibited statistically non-significant variation at day 30 and 45 of culture. On the whole, IBA increased rooting phenomenon and activated carbohydrate metabolism. IAA-oxidase appears to trigger and initiate root primordia, whereas POX is involved in both initiation and elongation of roots.

Molecular cloning and expression analysis of the MTN gene during adventitious root development in IBA-induced tetraploid black locust

5′-Methylthioadenosine (MTA) nucleosidase (MTN) plays a key role in the methionine (Met) recycling pathway of plants. Here, we report the isolation of the 1158bp full-length, cDNA sequence encoding tetraploid black locust (Robinia pseudoacacia L.) MTN (TrbMTN), which contains an open reading frame of 810bp that encodes a 269 amino acid protein. The amino acid sequence of TrbMTN has more than 88% sequence identity to the MTNs from other plants, with a closer phylogenetic relationship to MTNs from legumes than to MTNs from other plants. Subcellular localization analysis revealed that the TrbMTN gene localizes mainly to the cell membrane and cytoplasm of onion epidermal cells. Indole-3-butyric acid (IBA)-treated cuttings showed higher TrbMTN transcript levels than untreated control cuttings during root primordium and adventitious root formation. TrbMTN and key Met cycle genes showed differential expression in shoots, leaves, stems, and roots, with the highest expression observed in stems. IBA-treated cuttings also showed higher TrbMTN activity than control cuttings during root primordium and adventitious root formation. These results indicate that TrbMTN gene might play an important role in the regulation of IBA-induced adventitious root development in tetraploid black locust cuttings.

Molecular cloning, characterization and expression analysis of the SAMS gene during adventitious root development in IBA-induced tetraploid black locust.

S-Adenosylmethionine synthetase (SAMS) catalyzes the synthesis of S-adenosylmethionine (SAM), a precursor for ethylene and polyamine biosynthesis. Here, we report the isolation of the 1498 bp full-length cDNA sequence encoding tetraploid black locust (Robinia pseudoacacia L.) SAMS (TrbSAMS), which contains an open reading frame of 1179 bp encoding 392 amino acids. The amino acid sequence of TrbSAMS has more than 94% sequence identity to SAMSs from other plants, with a closer phylogenetic relationship to SAMSs from legumes than to SAMS from other plants. The TrbSAMS monomer consists of N-terminal, central, and C-terminal domains. Subcellular localization analysis revealed that the TrbSAMS protein localizes mainly to in the cell membrane and cytoplasm of onion epidermal cells and Arabidopsis mesophyll cell protoplasts. Indole-3-butyric acid (IBA)-treated cuttings showed higher levels of TrbSAMS transcript than untreated control cuttings during root primordium and adventitious root formation. TrbSAMS and its downstream genes showed differential expression in shoots, leaves, bark, and roots, with the highest expression observed in bark. IBA-treated cuttings also showed higher SAMS activity than control cuttings during root primordium and adventitious root formation. These results indicate that TrbSAMS might play an important role in the regulation of IBA-induced adventitious root development in tetraploid black locust cuttings.

Physiological changes in M 26 and M 106 softwood apple (Malus sp. Mill.) cuttings during their rooting

The levels of rooting cofactors, monohydroxyphenols, o-dihydroxyphenols, total phenols and protein, as well as the activity of peroxidase and polyphenol oxydase were compared in the leaves and stems of untreated vs IBA-treated cuttings. The cuttings of M 26 and M 106 clone were analysed on days: 0, 16 and 24 of rooting. Marked differences were found between the clones and treatments compared in levels of the substances analysed but these were not correlated with the rooting ability of cuttings. Only low monophenols' content in the IBA-treated M 106 cutting stems was correlated with the best rooting obtained.

Effect of auxins on adventitious root development from nodal cuttings of Saraca asoka (Roxb.) de Wilde and associated biochemical changes

An attempt was made to induce rooting from nodal cuttings of Saraca asoca under controlled conditions and study its biochemical changes during rooting. The nodal cuttings were pretreated with different concentrations of IAA, NAA and IBA and kept in a growth chamber [25±2°C, 16 h photoperiod (55 µmolm-2s-1) with cool, white fluorescent lamps and 65% relative humidity] for 12 h. Among the three auxins used for pretreatment, IBA showed more positive response on rooting as compared to IAA and NAA within 4 weeks of transfer to growing medium under mist condition. Among four concentrations of IBA tested, 500 ppm gave maximum percentage of rooting, number of roots and root length. Therefore, IBA was used further in experiments for biochemical investigation. The adventitious rooting was obtained in three distinct phases that is induction (0 to 10 d), initiation (10 to 20 d) and expression (20 to 30 d). IAA-oxidase activity of IBA-treated cuttings increased slightly as compared to control. The activity was found to decrease during induction and initiation phases and increase during expression phase. The peroxidase activity in IBA-treated cuttings increased up to initiation phase and declined at the expression phase. Polyphenol oxidase activity increased both in IBA-treated and control cuttings during induction and initiation phase but declined slowly during expression phase. Total phenolic content was higher in IBA-treated cuttings, particularly in initiation and expression phases and it also correlated with peroxidase activity. Phenolics might be playing key role for induction of adventitious rooting, and phenolic compounds can be used as rooting enhancer in S. asoca, an important medicinal plant. Key words: Auxins, enzyme activity, nodal cuttings, Saraca asoca, propagation.

Promotion of Adventitious Roots in Chrysanthemum Cuttings by Soaking in Ozonated Water

To examine the effect of soaking in ozonated water (OW) on development of adventitious roots, basal ends of chrysanthemum cuttings (Chrysanthemum morifolium Ramat.) were soaked in 1, 3 or 5 mg L−1 OW, in an indol-3-butyric acid (IBA) solution prepared from a commercial root promoting agent or in distilled water (DW). At 20 day after transplanting (DAT), a significant increase in adventitious root number (ARN) was observed in the IBA-treated cuttings but early root elongation was delayed. When soaked in the 5 mg L−1 OW, ARN and total root length (TRL) grown over 40 mm were increased with a decrease in soaking duration (from 50 to 5 min). Lateral root number (LRN) of the cuttings soaked in the 3 mg L−1 OW for 1 h showed four times higher than that of the DW treatment at 19 DAT. Optimal combination of dissolved ozone concentration and soaking duration can promote early root elongation and LRN of chrysanthemum cuttings. From a comprehensive standpoint, a high DOC of OW with a short soaking duration (3 mg L−1 × 1 h and 5 mg L−1 × 5 min) worked as well as IBA for adventitious rooting of chrysanthemum cuttings. These findings indicate that ozonated water can be an alternative to root promotion agents for adventitious rooting of chrysanthemum cuttings.

Effect of Auxins on Adventitious Root Development from Single Node Cuttings of Camellia sinensis (L.) Kuntze and Associated Biochemical Changes

An attempt was made to induce rooting from single node cuttings of Camellia sinensis var. TV-20 under controlled conditions and study its biochemical changes during rooting. The nodal cuttings were pretreated with different concentrations of IAA, NAA and IBA and kept in a growth chamber (25 ±2 °C, 16 h photoperiod (55 μ mol m−2 s−1) with cool, white fluorescent lamps and 65% relative humidity) for 12 h. Among the three auxins used for pretreatment, IBA showed more positive response on rooting as compared to IAA and NAA within 2 weeks of transfer to potting medium. Among four concentrations of IBA tested, 75 ppm gave maximum percentage of rooting, number of roots and root length. Therefore, IBA was used further in experiments for biochemical investigation. The adventitious rooting was obtained in three distinct phases i.e. induction (0–12 days), initiation (12–14 days) and expression (14–18 days). IAA-oxidase activity of IBA-treated cuttings increased slightly as compared to control. The activity was found to decrease during induction and initiation phases and increase during expression phase. The peroxidase activity in IBA-treated cuttings increased up to initiation phase and declined at the expression phase. Polyphenoloxidase activity increased both in IBA-treated and control cuttings during induction and initiation phase but declined slowly during expression phase. Total phenolic content was higher in IBA-treated cuttings, particularly in initiation and expression phases and it also correlated with peroxidase activity. Phenolics might be playing key role for induction of adventitious rooting, and phenolic compounds can be used as rooting enhancer in tea plant.

Activity and isoforms of peroxidases, lignin and anatomy, during adventitious rooting in cuttings of Ebenus cretica L.

Adventitious rooting of Ebenus cretica cuttings was studied in order to examine a) the rooting ability of different genotypes in relation to electrophoretic patterns of peroxidases. b) the activity and electrophoretic patterns of soluble and wall ionically bound peroxidases, the lignin content and anatomical changes in the control and IBA treated cuttings of <rooting> and <non-rooting> genotypes in the course of adventitious root formation. In addition, a fraction of soluble cationic peroxidases was separated by gel filtration chromatography from the total soluble peroxidases of a <rooting> genotype. No rooting occurred in cuttings without IBA-treatment. In both genotypes, electrophoretic patterns of soluble anionic peroxidases revealed two common peroxidase isoforms, while a fast-migrating anionic peroxidase isoform (A3) appeared only in <rooting> genotypes. Both genotypes showed similar patterns of soluble, as well as wall ionically bound cationic peroxidase isoforms. The number of isoforms was unchanged during the rooting process (induction, initiation and expression phase) but an increase in peroxidase activity (initiation phase) followed by decrease has been found in IBA-treated cuttings. During initiation phase the lignin content was almost similar to that on day 0 in <rooting> genotype while it was reduced at by about 50% in <non-rooting> genotype at the respective time. Microscopic observations revealed anatomical differences between genotypes. According to this study, the <rooting> and <non-rooting> genotypes display differences in anatomy, lignin content, activity of soluble peroxidases and the electrophoretic patterns of soluble anionic peroxidase isoforms. The A3-anionic peroxidase isoform could be used as biochemical marker to distinguish <rooting> and <non-rooting> genotypes of E. cretica and seems to be correlated to lignin synthesis in rooting process.

The role of vegetative propagation in the domestication of Pausinystalia johimbe (K. Schum), a highly threatened medicinal species of West and Central Africa

Pausinystalia johimbe (K. Schum), a tree of the Central Africa humid lowlands, is exploited for its bark to supply both export and local medicinal plant markets. The gradual destruction of the forests in which Yohimbe grows coupled with unsustainable bark harvesting methods, has resulted in local scarcity of this tree species. The study examined the amenability of P. johimbe to vegetative propagation through the rooting of leafy stem cuttings using low-cost technology polythene propagators. Using single-node leafy cuttings, three experiments were investigated in Cameroon: (i) Three propagation media (sawdust and 50:50 mixture of sand and sawdust). Initially, rooting was best in the mixed medium, but subsequently, cuttings set in the sawdust rooted better than those in sand and the mixture of sand/sawdust. However, there was no significant ( P >0.05) treatment effect on rooting percentage or on the mean number of roots per cutting. (ii) Three types of auxin at 50 μg per cutting (IAA, indole-3-acetic acid; IBA, indole-3-butyric acid and NAA, 1-naphthalene acetic acid) dissolved in 10 μl of alcohol. The control treatment received 10 μl of alcohol only. Significant differences in rooting percentage occurred after 3–4 weeks between the auxin-treated cuttings and the control. Within the same period IBA-treated cuttings rooted better than those with NAA and IBA. (iii) Four leaf areas: 0, 50, 100 and 200 cm 2 . Leafy cuttings rooted better than leafless cuttings after 4–5 weeks, with 50 cm 2 leaf area being the best from week 6. Significantly higher cutting mortality ( P <0.05) occurred for leafless cuttings than for leafy cuttings. The present study clearly indicated that P. johimbe is amenable to vegetative propagation technique using juvenile single-node leafy cuttings.

The role of vegetative propagation in the domestication of Pausinystalia johimbe (K. Schum), a highly threatened medicinal species of West and Central Africa

Pausinystalia johimbe (K. Schum), a tree of the Central Africa humid lowlands, is exploited for its bark to supply both export and local medicinal plant markets. The gradual destruction of the forests in which Yohimbe grows coupled with unsustainable bark harvesting methods, has resulted in local scarcity of this tree species. The study examined the amenability of P. johimbe to vegetative propagation through the rooting of leafy stem cuttings using low-cost technology polythene propagators. Using single-node leafy cuttings, three experiments were investigated in Cameroon: (i) Three propagation media (sawdust and 50:50 mixture of sand and sawdust). Initially, rooting was best in the mixed medium, but subsequently, cuttings set in the sawdust rooted better than those in sand and the mixture of sand/sawdust. However, there was no significant ( P>0.05) treatment effect on rooting percentage or on the mean number of roots per cutting. (ii) Three types of auxin at 50 μg per cutting (IAA, indole-3-acetic acid; IBA, indole-3-butyric acid and NAA, 1-naphthalene acetic acid) dissolved in 10 μl of alcohol. The control treatment received 10 μl of alcohol only. Significant differences in rooting percentage occurred after 3–4 weeks between the auxin-treated cuttings and the control. Within the same period IBA-treated cuttings rooted better than those with NAA and IBA. (iii) Four leaf areas: 0, 50, 100 and 200 cm 2. Leafy cuttings rooted better than leafless cuttings after 4–5 weeks, with 50 cm 2 leaf area being the best from week 6. Significantly higher cutting mortality ( P<0.05) occurred for leafless cuttings than for leafy cuttings. The present study clearly indicated that P. johimbe is amenable to vegetative propagation technique using juvenile single-node leafy cuttings.

Effect of indole-3-butyric acid on the endogenous indole-3-acetic acid and lignin contents in soybean hypocotyl during adventitious root formation

The effect of exogenous indole-3-butyric acid (IBA) on the peroxidase activity during adventitious root formation in hypocotyls of Glycine max was investigated. The hypocotyls of IBA-treated cuttings grew significantly higher numbers of adventitious roots with a decline in lignin levels that corresponded with a decrease in peroxidase activity. Both cationic and anionic peroxidase activities were inhibited during the process of rooting. In addition, the decrease of the cationic peroxidase transcript (pI 7.7) was also observed in IBA-treated hypocotyl during rooting.

Relationship of Carbohydrate Sources and Indole-3-Butyric Acid in Olive Cuttings

Indole-3-butyric acid (IBA) treatment improves rooting of easy-to-root and moderate-rooting olive cultivars, but does not stimulate root formation in hard-to-root cultivars. The rate of root formation in olive cuttings is slow and a source of carbohydrates is required to maintain and improve the effect of IBA. Sucrose treatment applied together with IBA and several times thereafter improved all rooting parameters: rooting percentage, number of adventitious roots and root length. During rooting, photosynthesis in the cuttings is very low and has almost no effect on the carbohydrate content, so that starch appears to be the major source of carbohydrates. Amyloplast levels decline during rooting and IBA increases the rate of their disappearance. A significant percentage of rooted olive cuttings collapse during their hardening process, when no starch pool is available. Only photosynthesis of fully-expanded leaves can contribute to the source of the carbohydrates needed by the rooted plants. However, when the top growth is reduced, as often occurs in IBA-treated cuttings, the carbohydrate supply may not be enough to keep the rooted plants alive and to support their growth and development. The data suggest that carbohydrates have an important role in rooting and improve the stimulatory effect of IBA in this process. During the stages involved in the formation of adventitious roots the endogenous carbohydrate pool is the main source of carbohydrates, while in young rooted plants the main source comes directly from the photosynthesis.

Hot-water Treatment and Indole-3-butyric Acid Stimulates Rooting and Shoot Development of Tropical Ornamental Cuttings

Frangipani (Plumeria hybrid `Donald Angus') cuttings immersed in hot water (49C for 10 min) followed by 0.8% indole-3-butyric acid (IBA) basal treatment (hot water + IBA) had greater root length and weight compared to the nontreated control, hot water, or IBA treatment alone. Greater percentage of rooting and number of roots per cutting were observed for hot-water-treated + IBA-treated cuttings compared to the non-treated control and hot-water treatment alone. In a second study, Dracaena fragrans (L.) Ker-Gawl. `Massangeana', D. deremensis Engl. `Warneckii', D. deremensis Engl. `Janet Craig', D. marginata Lam., and cape jasmine (Gardenia jasminoides Ellis) cuttings displayed results similar to those observed with Plumeria cuttings. In addition to enhancing rooting, hot water + IBA also stimulated the number of shoots per cutting on anthurium (Anthurium andraeanum Andre `Marian Seefurth'), croton [Codiaeum variegatum (L.) Blume var. pictum (Lodd.) Mull. Arg.], D. marginata, D. fragrans, Plumeria, and ti (Cordyline terminalis `Ti') cuttings.