Concentrations Of Indolebutyric Acid Research Articles

A culture system for the stable and high-efficiency proliferation of adventitious roots of Panax notoginseng and ginsenoside accumulation

Panax notoginseng is an important medicinal plant that belongs to the Araliceae family. In this study, a stable and high-efficiency system for the proliferation of P. notoginseng adventitious roots was established via two steps, and their growth and accumulation of three ginsenosides (Rg1, Re and Rb1) was analyzed in suspension culture. Adventitious roots were firstly induced from the cotyledons of P. notoginseng seeds, in 1/2 Schenk and Hildebrandt (SH) medium with 2.0 mg L−1 indole-3-butyric acid (IBA) and 30 g L−1 sucrose. Using these adventitious roots as explants, the influence of 1/2 SH and 1/2 Murashige and Skoog (MS) medium without NH4NO3 (1/2MS-N), and IBA (0–4.0 mg L−1) and naphthalene acetic acid (NAA) (0–2.0 mg L−1) on the induction of new adventitious roots was investigated. Culture conditions of 1/2 SH with 2.0 mg L−1 IBA and 2.0 mg L−1 NAA were optimal for the formation of new adventitious roots, and led to an induction rate of 100 % and 12.62 new adventitious roots on average for each explant after 3 weeks of culture. In culture conditions of 1/2MS-N with 2.0 mg L−1 IBA and 50 g L−1 sucrose, induced adventitious roots rapidly elongated to a mean length of 14.23 mm within 3 weeks, demonstrating that a two-step process of adventitious root regeneration involving steps of initiation and elongation was most effective. Suspension cultures of adventitious roots were analyzed to evaluate the effects of culture cycle time, concentrations of sucrose and IBA and amount of inoculation on adventitious roots. After 7 weeks, the total yield of three ginsenosides (11.13 mg 100 mL-1) was highest in root cultures with 1/2 MS-N, 30 g L−1 sucrose, 4.0 mg L−1 IBA, and 3.5 g 100 mL−1 root inoculation culture. The highest total concentration of ginsenosides (18.58 mg g−1 DW) was obtained from adventitious roots cultured from 3.0 g 100 mL−1 inoculation material and the concentration of ginsenoside Re (8.05 mg g−1 DW) was 1.8-fold higher than that in 3-year-old roots cultivated in the field (4.44 mg g−1 DW). The establishment of this culture system will be beneficial for the scale-up culture of adventitious roots and ginsenoside production in P. notoginseng.

Highly Successful Adventitious Root Formation of Zamia L. Stem Cuttings Exhibits Minimal Response to Indole-3-Butyric Acid

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.

Ginkgo biloba L. mini-cuttings: indole butyric acid, substrates, and biochemical composition of the mother plants

The objective of this study was to evaluate the viability of the Ginkgo biloba mini-cutting technique, as well as the influence of substrates and different concentrations of indole butyric acid (IBA) on adventitious rooting in addition to the protein and sugar content in the mini-cutting. Mini-cuttings were 4 ± 1 cm in length, with the bases immersed in solutions of 0, 1000, 2000, and 3000 mg L-1 IBA. They were then planted in polypropylene tubes using two substrates (vermiculite and Tropstrato®) and maintained under greenhouse conditions for 60 d. The experiment was carried out with a 2 × 4 factorial scheme (substrates × IBA). There was no influence of IBA application on the promotion of rhizogenesis in Ginkgo biloba mini-cuttings. The rooting percentages were higher than 55% regardless of the treatment used. The vermiculite substrate showed a higher number of roots (4.94) and lower mortality (11.60) of mini-cuttings than Tropstrato®. We conclude that the mini-cutting technique is feasible for Ginkgo biloba, and the use of IBA is not necessary. We found that the induction ofadventitious rooting depended on the biochemical composition of the mother plants, due to the translocation of non-reducing sugars and leaf proteins for root formation.

Multiplication and <i>in vitro</i> rooting of <i>Handroanthus impetiginosus</i> (Mart. Ex DC.) Mattos

Este estudo objetivou avaliar a influência das citocininas durante o estágio de multiplicação in vitro e a combinação entre carvão ativado com o ácido indol-3-butírico (AIB) durante o enraizamento in vitro de Handroanthus impetiginosus. Para a multiplicação in vitro, os segmentos nodais dos brotos obtidos a partir do estabelecimento de plântulas in vitro foram inoculados em meio de cultura Woody Plant Medium (WPM), com e sem as seguintes concentrações de 6-benzilaminopurina (BAP), cinetina (KIN) e tidiazuron (TDZ): 0,5; 1,0; 2,0; 4,0 e 8,0 µmol L-1. Para o enraizamento in vitro, brotos foram inoculados em meio WPM contendo combinações entre AIB (1,0; 3,0; 6,0 e 9,0 μmol L-1) e carvão ativado (1,0; 2,0 e 3,0 g L‑1), bem como suas ausências no meio de cultura. O maior número de brotos e gemas foi alcançado após usar 8,0 μmol L-1 de TDZ, enquanto que o melhor enraizamento ocorreu após a adição de 2,0 g L-1 de carvão ativado, independente da concentração de AIB. Nossos resultados mostram que usar TDZ em níveis adequados para o estágio de multiplicação in vitro seguido pelo uso de 2,0 g L-1 de carvão ativado para obter brotos bem enraizados é eficiente para a micropropagação de ipê-roxo de maneira rápida e com baixo custo, além de fornecer conhecimento sobre como manter esta espécie ameaçada de extinção em um ambiente in vitro podendo ajudar outros estudos de conservação.

Effect of indole-butyric acid (IBA) and wounding on rooting ability and vegetative characteristics of apple rootstock cuttings under Nepal conditions

Use of seedling rootstocks is widespread in Jumla and research on the evaluation of clonal rootstocks for propagation has still not started. Study on the concentration of IBA and wounding effect in cuttings is also deficit. Therefore, this investigation was carried out in the Hi-tech Greenhouse of Kalika nursery in Jumla, Nepal from February to July, 2018 to investigate the rooting response of MM111 apple rootstock to wounding (with or without) and various Indole-Butyric Acid (IBA) concentrations (0, 2000, 2500 and 3000 ppm). The experiment was laid out in a factorial Complete Randomized Design by preparing cuttings of 20 cm length and 5 to 10 mm diameter and planting them in rooting media made by mixing perlite, cocopeat, forest soil and vermicompost in 1:1:1:1 ratio after 15 second of quick dip in IBA solution. All the rooting and vegetative parameters were significantly affected by different concentration of IBA solution and wounding. The results revealed minimum number of days to first sprouting (15.50), highest rooting percentage (68.52%), highest number of roots per cutting (23.11), highest length of the longest root (22.83 cm), maximum diameter of main sprout (2.92 mm), maximum number of leaves at 86 DAT(20.06), 93 DAT(22.50) and 100 DAT(30.17) in the cuttings treated with IBA 2000 ppm. Increasing the IBA concentration beyond 2000 ppm produced negative effects. Similarly, wounding resulted in better root and shoot parameters of cuttings than with no wounding. The rooting percentage (57.4%), number of roots per cutting (21.83), length of the longest root (20.96 cm), diameter of the main sprout (2.66 mm) were significantly higher in wounded cuttings which also recorded the lower days for first sprouting. The interaction effect was significant (p<0.01) only on the rooting percentage while all other parameters were non-significant. The results indicated that 2000 ppm IBA with basal wounding perform better than other treatments.

Gentiana clusii Perr.&Song.: Enhanced production of secondary metabolites by in vitro propagation

Shoot and root in vitro culture of endemic European species Gentiana clusii was established for the first time. The effects of different concentrations of benzyl adenine (BA), 6-phurphurylaminopurine (KIN), indole-3-butyric acid (IBA) and naphthalene acetic acid (NAA) on shoot propagation and rooting of G. clusii were investigated. The optimal in vitro conditions for shoot propagation and long-term maintenance were achieved using woody plant medium (WPM) supplemented with 0.5 mg l−1 KIN, and subsequent application of IBA at 0.5 mg l−1 significantly improved rooting of these shoots. Root culture was established from excised root tips cultured in ½ MS liquid media with increasing concentrations of IBA (0.1–1.0 mg l−1). A high root growth rate and considerable biomass yield were obtained by addition of 1.0 mg l−1 IBA. HPLC analysis revealed that in vitro culture considerably promoted the production of secondary metabolites in G. clusii. The selected protocol for shoot propagation (WPM + 0.5 mg l−1 KIN) increased the content of sweroside, gentiopicrin and norswertianin-1-O-primeveroside (N-1-P) for more than 2-fold compared with the wild plants. IBA promoted N-1-P and norswertianin production in root cultures; their contents were enhanced 6.4- and 18.6-fold, respectively, compared with the wild plants. The extract of these roots displayed the highest antioxidant capacity (IC50 = 66.57 μg ml−1). The established shoot and root propagation protocols facilitate in vitro conservation of G. clusii, and provides a promising tool for the large scale production of valuable secoiridoids and xanthones.

Stimulating capability of IBA on rooting in stem cuttings of Pseuderanthemum carruthersii var. atropurpureum

The current study was aimed to find the effect of IBA on rooting of cuttings in Pseuderanthemum carruthersii var. atropurpureum 'Variegatum'. The experiment was laid out in Completely Randomized Block Design (CRD) with 3 replications, including six treatments of various concentration of Indole 3-Butyric Acid (IBA) solutions viz., 250 ppm, 500 ppm, 1000 ppm, 2000 ppm, 3000 ppm and control (without any treatment). Minimum days for sprouting (7.12 days), number of roots per cutting (14.23) and root length (9.79 cm) are recorded maximum IBA 3000 ppm. All the IBA treatments are on par with each other and significantly higher than control in survival percentage. From this experiment we conclude that, the rooting and survival capacity of terminal stem cuttings of Eranthemum bicolor under mist chamber conditions, can be improved by quick dipping of basal portion of cuttings on IBA with 3000 ppm concentration.

Etiolation and indolbutyric acid in the Olea europaea cv. Maria da Fé minicuttings

This study aims to evaluate the effect of etiolation and the usage of indolbutyric acid (IBA) in the propagation of Olea europaea cv. Maria da Fe minicuttings. The experimental outline is a completely randomized design, with a 2 x 3 bifactorial scheme [minicuttings from plants with and without etiolation and three concentrations of indolbutyric acid (0, 1,000, and 2,000 mg L-1)]. After 110 days, the following has been evaluated: percentage of survival, foliar retention and rooting, number of roots, length of the largest root, root dry matter mass and percentage of unrooted minicuttings with calluses. For the percentage of survival, foliar retention and rooting, number of roots and root dry matter mass, there has only been significance for IBA concentrations, and in general, the IBA 1,000 mg L-1 concentration provided the highest scores. For the length of the largest root and minicuttings with non-rooted callus, there has been interaction between treatments, with the lowest scores for callus formation in the minicuttings with etiolation and without IBA. It can be concluded that the minicutting of Olea europaea cv. Maria da Fe can be carried out without etiolation in the mother plants, using 1,000 mg L-1 of IBA.

Propagation of native plants with ornamental potential from Serra do Oratório, Santa Catarina State, Brazil

Abstract The use of native plants enriches the landscape projects, conserves the local flora, creates a local identity and promotes the symbiosis between native fauna and flora. The objective of the present study was to evaluate the vegetative propagation of the native species Calibrachoa sellowiana, Tibouchina dubia and Verbena rigida, using cuttings submitted to different concentrations of indolebutyric acid (IBA), naphthaleneacetic acid (NAA) and substrates. From the stock plants, the cuttings were excised from the apex, with leaves number varying according to the species. In the propagation of Calibrachoa sellowiana, Tibouchina dubia and Verbena rigida under different concentrations of IBA, 4 treatments were carried out, consisting of IBA at concentrations of 0 mg L-1 (control), 500 mg L-1, 1000 mg L-1 and 2,000 mg L-1. In the propagation of Tibouchina dubia under different concentrations of NAA, the experiment was developed using four treatments, NAA was diluted in acetone + talc at concentrations of 0 mg L-1 (control), 2,000 mg L-1, 4,000 mg L-1 and 6,000 mg L-1. The evaluated variables for all the experiments were: percentage of rooted cuttings, number of roots per rooted cutting, average root length (cm) and number of shoots. In the substrate experiment, the treatments were sand, vermiculite, Plantmax® and mixture of soil + sand, for all the species from the previous experiments. Calibrachoa sellowiana and Verbena rigida, rooted with low concentration of IBA, 0 e 500 mg L-1, respectively, but the PGR was not essential to rooting phase, since the control also developed roots. For Tibouchina dubia the IBA and NAA did not promoted rooting. Calibrachoa sellowiana rooted better with soil + sand, differing from Verbena rigida, which rooted better with Plantmax®.

Rooted cuttings by IBA (Indole butyric acid) and NAA (Naphthalene acetic acid) in black pepper (piper nigrum) - A case study in Vietnam

In order to investigate the effect of IBA (Indole Butyric Acid) and NAA (Naphthalene Acetic Acid) on rooted cuttings, there were two experiments were conducted. The first experiment was two factor experiment where IBA and NAA were applied as different concentrations to main stems (cuttings). There were 14 treatments and 4 replications, including 20 pots/treatment; 1,120 pots in total. Similarly, the second was also two factor experiment consisted of IBA and NAA in different concentrations. The total of 800 pots were divided into 10 treatments and 4 replications. The results showed that application of IBA at concentrations of 5,000 ppm on cuttings showed highest plant parameters in terms of plant and root growth. On the other hand, rooting hanging shoots could be found at lower concentrations of IBA 300 ppm and NAA 400 ppm. It is concluded that IBA and NAA can be used in vegetative propagation to improve success rare and obtain better cutting growth.

Vegetative propagation of <i>Afzelia africana</i> Sm. Ex Pers.: a multipurpose and threatened tree

Afzelia africana is at the verge of extinction from continuous exploitation without replacement, thus propagation of this tree species is expedient. Vegetative propagation is a reliable means of propagation of tree species. This study therefore describes a protocol for the vegetative propagation of Afzelia africana by using stem cuttings from its mature tree (20 years old) and saplings (2 years old). Herbaceous (non - lignified portion of the stem) and semi – hard wood cuttings (lignified portion of the stem) (with and without leaves) were treated with high and low concentrations of Indole butyric acid (IBA) solution via the quick dip and the soaking method of application and planted on forest soil and river sand in a humidifier. Cuttings from mature tree planted on forest soil and river sand did not respond to any treatment. Also, no response was observed on cuttings collected from saplings and planted on forest soil; however, cuttings planted on river sand sprouted. The presence and absence of leaves and IBA treatment had an interaction effect on root number (0.02) and root length (0.0001). The response from herbaceous cuttings was significantly higher than from semi – hard wood cuttings with respect to root number (1.00) and root length (5.82 cm). Cutting type and IBA treatment also had an interaction effect on root number (0.05) and root length (0.0007). Herbaceous leafy stem cuttings of A. africana treated with 400 ppm IBA and planted on river sand is suitable for rooting stem cuttings of A. africana for raising seedlings for reforestation, afforestation and other conservation purposes.
 © 2020 International Formulae Group. All rights reserved.
 Keywords: Rooting, cuttings, Afzelia africana, hormone, humidifier

Enhanced production of anthraquinones and phenolic compounds using chitosan from the adventitious roots of Morinda coreia Buck. and Ham.

This report establishes the production and characterization of anthraquinones and phenolic compounds from the adventitious root cultures of Morinda coreia, induced from the leaves on half strength Murashige and Skoog’s (MS) medium fortified with 1.0 mg l−1 of Indole-3 butyric acid (IBA). The in vitro regenerated adventitious roots (AR) were treated with various concentrations of IBA (0.5–5.0 mg l-1) containing half-strength of liquid MS medium with sucrose (1.5 %). The maximum amount of anthraquinones (149.80 mg g−1 dry weight of AR) and phenolic compounds (71.6 mg g−1 dry weight of AR) were detected on 1.0 mg l−1 and 4.0 mg l−1 of IBA respectively. These proliferated AR on IBA contained 2.10 times more anthraquinones and 1.89 times more phenolics as compared with the yield of in vivo grown roots of M. coreia. Other parameters, such as growth ratio (5.082), fresh weight (1.568 g) and dry weight (0.163 g) of AR were recorded maximum with the concentration of 1.0 mg l−1 IBA. These AR were introduced into the two-stage culture system with various concentrations of chitosan (0.2, 0.4 and 0.8 mg ml-1) for elicitation. Among these, 0.4 mg ml-1 chitosan was observed as the best concentration and further used for the production of secondary metabolites (anthraquinones and phenolics) at different time intervals (2–8 days). Growth ratio and biomass (fresh and dry weight) were decreased from second to eighth day of elicitation but the amount of anthraquinones (292.038 mg g-1 dry weight) and phenolics (86.8 mg g-1 dry weight) were increased till 4th day of the elicitation. The methods developed in this study could be used for further proliferation of AR and large scale production of anthraquinones and phenolic compounds using in vitro raised leaves of M. coreia.

Vegetative Propagation of Himatanthus sucuuba (Spruce ex Müll. Arg.) Woodson by Stem Cuttings

The vegetative propagation by cuttings can be an advantageous alternative to the production of Himatanthus sucuuba seedlings because it allows the obtention of a large number of plants genetically identical to the matrix plant in a shorter time and space. However, such a technique is simultaneously influenced by different factors that can compromise its success. In this sense, the present study aimed to evaluate the effect of different types of cuttings and indole-3-butyric acid (IBA) concentration, on the survival and rooting of cuttings of H. sucuuba. The experimental design used was in randomized complete blocks, with a factorial arrangement: 2 types of cuttings (with and without leaves) and 3 concentrations of IBA (0, 1000 and 3000 mg L–1). After 100 days, were evaluated the following variables: survival (%), rooting (%), number of roots per cutting, length of the largest root (cm), number of leaves and dry biomass. The data were subjected to analysis of variance (ANOVA) and means compared by Tukey’s test at p < 0.05. The survival and rooting percentages were higher than 70% in all treatments. There was no significance for the interaction of the factors analyzed, neither for the effect of AIB, analyzed in isolation. The type of stake exerted the greatest influence, with emphasis on the cuttings with leaves, which stood out in most of the factors analyzed. The propagation of H. sucuuba to cuttings was considered viable, and the maintenance of the leaves, associated with juvenility of the propagules, was determining factors in the conditions in which this study was developed.

Quality of light and indolbutyric acid in vitro rooting of lavender

Abstract Lavender, an aromatic and medicinal plant, used in the extraction of essential oil, as an ornamental and meliferous plant, can be successfully propagated as long as the light, the nutrient medium and the growth regulators are adequate. The aim of the study was to evaluate the effect of different concentrations of indolebutyric acid (IBA) associated to distinct light spectra, on the in vitro rooting of Lavandula angustifolia. The experiment consisted in the combination of two concentrations of indolebutyric acid in the growth medium (0 and 0.1 mg L-1) and two light spectra, using cellulose acetate filters (blue and red), besides the control (without filter), totaling six treatments with four repetitions. For each repetition five explants were used. After 30 days, the variables evaluated were: survival percentage, number of buds and leaves, shoot length, number of roots, length of the longest root, shoot fresh and dry matter weight. There was a significant interaction among the indolebutyric acid concentrations and the light filters for the variables number of buds, leaves and roots and shoot length. Except for leaf number, promising results were obtained when the explants were held under red filters and with a concentration of 0 mg L-1 of indolebutyric acid in the growth medium. From these results, it can be concluded that the best in vitro rooting of Lavandula angustifolia is obtained when there is no indolebutyric acid in the growth medium associated with the use of the red filter.

Propagation of Three Cultivars of Rosa hybrida L. through Stenting Method

In the commercial production of roses, introducing a method to reduce the time of propagation with maximum success is crucial. This study was conducted to investigate the effect of different concentrations (0, 1500, 3000, 4500 mg/L) of Indole-3-butyric acid (IBA) on propagation of three cultivars of Rosa hybrid L. ('Dolce Vita', 'Samurai' and 'Utopia') by stenting (simultaneous cutting and grafting) method under greenhouse conditions. The cultivars were grafted onto Rosa hybrida L. 'Natal Briar' rootstock. The factorial experiment was performed in a completely randomized design with three replications. The stentings were cultured in coco peat and perlite medium at 1:2 ratio in a greenhouse under mist system. After 60 days, the percentage of grafting, rooting percentage, root number, longest root length and fresh and dry weights of roots and shoot traits (including leaf number, shoot number, and longest shoot length) were determined on the stentings. The highest rate of rooting in Dolce Vita cultivar was obtained at 1500 mg/L IBA and in Samurai and Utopia cultivars at 4500 mg/L IBA. Among the three cultivars of roses, highest percentage of rooting (93.75%), healing percentage (93.75%), root length (12.47 cm), fresh weight (0.84 g) and dry weight (0.07 g) of roots were observed in stentings treated with 4500 mg/L of IBA in Rosa hybrida L. cv. Samurai. Interaction between IBA concentrations and cultivars on chlorophyll (a, b and total) and carotenoid contents were significant in all the three cultivars of roses.

Rooting of azalea cuttings of Otto and Terra Nova cultivars treated with auxin and boron

Abstract Azalea (Rhododendron simsii Planch.) is an ornamental plant native to China, propagated commercially by cuttings and cultivated in Brazil due to the beauty of its flowers. However, it presents rooting difficulties, which can lead to a reduction in the commercial production of these seedlings. Thus, the application of plant regulators is necessary to achieve rooting success as well as of nutrients that are involved in biochemical and physiological plant processes. This work aimed to evaluate the rooting performance of Otto and Terra Nova azalea herbaceous cuttings treated with indolebutyric acid (IBA) and boron. The experiments were conducted at a private property specialized in the production of potted azalea, located in Holambra County, São Paulo State, Brazil, and the evaluations were carried out at the Plant Seed Laboratory of the Crop Production Department, São Paulo State University (Unesp), School of Agricultural and Veterinarian Sciences, Jaboticabal. The experimental design for each experiment with each cultivar was completely randomized. The treatments were arranged in a 4x4 factorial scheme (IBA concentrations x boron concentrations) with four replications and 10 cuttings per replication. The evaluation was performed six weeks after experiment beginning. Auxin and boron did not influence rooting percentage of cuttings of both cultivars. However, Otto cultivar presented a better-quality root system when cuttings were treated with 2,000 mg L−1 IBA in the absence of boron.

The effects of rooting media, IBA, and clones on rooting ability of Teak’s shoot cutting

Clonal forestry of teak in the community forest could increase the forest productivity where the shoot cutting was one of the vegetative propagation methods to propagate and maintain the superior clone of teak. However, the major problem on the shoot cutting of teak was the difference in rooting ability among rooting media, IBA (Indolebutyric Acid) and selected superior of teak clone. The research was conducted on split-split plot design with 10 individual as replication on each treatment. The main plot was two rooting media (cocopeat:rice husk 2:1/A; and soil:sand:compost 3:2:1/B). The subplot was IBA hormone concentration (0 ppm, 50 ppm, 100 ppm, 150 ppm) and the sub-sub plot was 11 clones of teak. The result showed that the rooting ability of teak was affected by all of treatments and interaction among them (P < 0.05), except for the interaction between IBA dosage and clone (P >0.05). The primary and secondary root length showed that clone and interaction between media and clone were significantly different (P < 0.05), while the media was only significantly different for secondary root length (P < 0.05). However, the number of primary and secondary root was not affected by the treatments (P>0.05). Moreover, the best result of rooting ability of teak for rooting media, IBA and was the cocopeat:rice husk (70,53%), IBA 150 ppm (53.18%) and clone WG2 (85%), respectively. It suggested that the seedling production of superior teak through the shoot cutting method depended on the rooting media, IBA concentration, and the specific of teak clone.

Dynamic Transcriptome Analysis Reveals Uncharacterized Complex Regulatory Pathway Underlying Dose IBA-Induced Embryogenic Redifferentiation in Cotton.

The somatic embryogenesis (SE) process of plants is regulated by exogenous hormones. During the SE, different genes sensitively respond to hormone signals through complex regulatory networks to exhibit plant totipotency. When cultured in indole-3-butyric acid (IBA) concentration gradient medium supplemented with 0 mg dm−3, 0.025 mg dm−3, and 0.05 mg dm−3 IBA, the callus differentiation rate first increased then decreased in cotton. To characterize the molecular basis of IBA-induced regulating SE, transcriptome analysis was conducted on embryogenic redifferentiation. Upon the examination of the IBA’s embryogenic inductive effect, it was revealed that pathways related to plant hormone signal transduction and alcohol degradation were significantly enriched in the embryogenic responsive stage (5 days). The photosynthesis, alcohol metabolism and cell cycle pathways were specifically regulated in the pre-embryonic initial period (20 days). Upon the effect of the IBA dose, in the embryogenic responsive stage (5 days), the metabolism of xenobiotics by the cytochrome P450 pathway and secondary metabolism pathways of steroid, flavonoid, and anthocyanin biosynthesis were significantly enriched. The phenylpropanoid, brassinosteroid, and anthocyanin biosynthesis pathways were specifically associated in the pre-embryonic initial period (20 days). At different developmental stages of embryogenic induction, photosynthesis, flavonoid biosynthesis, phenylpropanoid biosynthesis, mitogen-activated protein kinase (MAPK) signaling, xenobiotics metabolism by cytochrome P450, and brassinosteroid biosynthesis pathways were enriched at low a IBA concentration. Meanwhile, at high IBA concentration, the carbon metabolism, alcohol degradation, circadian rhythm and biosynthesis of amino acids pathways were significantly enriched. The results reveal that complex regulating pathways participate in the process of IBA-induced redifferentiation in cotton somatic embryogenesis. In addition, collections of potential essential signaling and regulatory genes responsible for dose IBA-induced efficient embryogenic redifferentiation were identified. Quantitative real-time PCR (qRT-PCR) was performed on the candidate genes with different expression patterns, and the results are basically consistent with the RNA-seq data. The results suggest that the complicated and concerted IBA-induced mechanisms involving multiple cellular pathways are responsible for dose-dependent plant growth regulator-induced SE. This report represents a systematic study and provides new insight into molecular signaling and regulatory basis underlying the process of dose IBA-induced embryogenic redifferentiation during SE.

A highly efficient organogenesis protocol based on zeatin riboside for in vitro regeneration of eggplant

BackgroundEfficient organogenesis induction in eggplant (Solanum melongena L.) is required for multiple in vitro culture applications. In this work, we aimed at developing a universal protocol for efficient in vitro regeneration of eggplant mainly based on the use of zeatin riboside (ZR). We evaluated the effect of seven combinations of ZR with indoleacetic acid (IAA) for organogenic regeneration in five genetically diverse S. melongena and one S. insanum L. accessions using two photoperiod conditions. In addition, the effect of six different concentrations of indolebutyric acid (IBA) in order to promote rooting was assessed to facilitate subsequent acclimatization of plants. The ploidy level of regenerated plants was studied.ResultsIn a first experiment with accessions MEL1 and MEL3, significant (p < 0.05) differences were observed for the four factors evaluated for organogenesis from cotyledon, hypocotyl and leaf explants, with the best results obtained (9 and 11 shoots for MEL1 and MEL3, respectively) using cotyledon tissue, 16 h light / 8 h dark photoperiod conditions, and medium E6 (2 mg/L of ZR and 0 mg/L of IAA). The best combination of conditions was tested in the other four accessions and confirmed its high regeneration efficiency per explant when using both cotyledon and hypocotyl tissues. The best rooting media was R2 (1 mg/L IBA). The analysis of ploidy level revealed that between 25 and 50% of the regenerated plantlets were tetraploid.ConclusionsAn efficient protocol for organogenesis of both cultivated and wild accessions of eggplant, based on the use of ZR, is proposed. The universal protocol developed may be useful for fostering in vitro culture applications in eggplant requiring regeneration of plants and, in addition, allows developing tetraploid plants without the need of antimitotic chemicals.

VEGETATIVE PROPAGATION OF HYMENAEA COURBARIL L. AND APULEIA LEIOCARPA (VOGEL) J. F. MACBR. BY MINI-CUTTING

ABSTRACT The objective of this work was to evaluate the vegetative propagation of Hymenaea courbaril (jatobá) and Apuleia leiocarpa (garapa) using the mini-cutting technique with the use of indolebutyric acid (IBA) growth regulator in different types of mini-cuttings. Two experiments were set up: the first involving the two species and three mini-cutting techniques (basal, intermediate and apical) in the presence and absence of IBA (4000 mg kg-1). In the second experiment, only the garapa species was evaluated by testing the same three mini-cutting techniques at four IBA concentrations: 0, 1000, 2000 and 4000 mg kg-1. The mini-cuttings were obtained from 6-month-old seedlings produced from seeds in a nursery. A randomized block design was used in a 3 x 2 x 3 factorial scheme (three mini-cutting techniques, two IBA concentration levels and three evaluation dates) in the first experiment, and a 3 x 4 x 3 factorial scheme (three mini-cutting techniques, four IBA concentrations and three evaluation dates) in the second experiment. At 90 days, jatobá had an average survival of 54%, with less than 5% of total rooting, without significant influence of the mini-cutting technique or IBA use. Garapa presented higher survival for the basal mini-cuttings in both experiments, which were the only ones that took root. IBA did not influence survival or rooting percentage of garapa mini-cuttings, but negatively influenced the root number, length and dry mass. We concluded that the basal mini-cutting is a viable technique for vegetative propagation of garapa, presenting 40% of rooting, but the propagation by mini-cutting for jatobá was not successful under the conditions of this study.