Immature Inflorescences Research Articles

Preparation and Sectioning of Paraffin-Embedded Tissue for Histology and Histochemistry.

Cutting thin sections of plant tissues enables observation of internal structures and inner cell layers, and it facilitates various histochemical staining methods. Paraffin embedding gives the tissues a uniform stiffness that is sufficient for sectioning with a microtome. Here, we describe the procedures for preparation of paraffin-embedded tissues and the techniques for sectioning with a microtome. This method is applicable to various types of tissues, including rice shoot apex and immature inflorescence.

Hepatoprotective potential of coconut inflorescence sap against paracetamol induced toxicity in hep G2 cell lines

Coconut Inflorescence Sap (CIS) is the sweet, oyster-white colored, non-fermented juice obtained from the immature inflorescence of the Coconut tree. Acetaminophen (N-acetyl-p-aminophenol, or paracetamol) is one of the most frequently used drugs worldwide as an antipyretic or analgesic. HepG2 cell lines were used as an experimental model for studying in vitro hepatotoxicity induced by Paracetamol. The present study aims to identify biologically active compounds of CIS using LCMS analysis and to elucidate the ameliorative potential of CIS in alleviating paracetamol-induced hepatotoxicity. LC-MS analysis revealed the presence of 17 bioactive compounds. HepG2 cells were pretreated with Paracetamol (20 mM) for inducing toxicity, and Silymarin at a concentration of 50 μg/ml was used as a standard drug. The morphological analysis and MTT assay showed effective recovery from toxicity in cells treated with CIS in a dose-dependent manner. CIS at 25 μg/ml potentially showed the highest percentage of inhibitory activity against the toxicity induced by paracetamol. The treatment with paracetamol significantly increased the indicators of liver toxicity - LDH, SGOT, SGPT, and Glut.S Transferase in the media.CIS administration also increased the total protein levels, SOD, and Catalase activity. The morphological analysis, MTT assay, cytocompatibility studies, determination of enzymatic activities, etc., confirms the significant hepatoprotective efficacy of CIS.

Essential Oil Content, Composition and Free Radical Scavenging Activity from Different Plant Parts of Wild Sea Fennel (Crithmum maritimum L.) in Montenegro.

This study was conducted to determine the sea fennel essential oil (SFEO) yield, composition, and antioxidant activity of leaves, stem, inflorescences, and umbels from seeds of wild sea fennel (SF) (Crithmum maritimum L.) from the Montenegro coast. The chemical composition of isolated essential oil was determined by GC/MS and GC/FID analyses. The antioxidant activity was determined using the DPPH assay. The maximum SFEO yield was found in umbels with seeds (4.77 mL/100 g p.m.). The leaves contained less EO (0.52 mL/100 g p.m.) than immature inflorescence (0.83 mL/100 g p.m.) The minimum EO content was found in the stem (0.08%). Twenty components were isolated from SFEO leaves, twenty-four from inflorescence, thirty-four components from the stem, and twenty-one components from umbels with seeds. Limonene (62.4-72.0%), γ-terpinene (9.5-14.0%), α-pinene (1.4-5.8%), and sabinene (1-6.5%) were found to be the main components of the SFEO from monoterpene hydrocarbons as dominant grouped components (86% to 98.1%). SF plant parts showed differences in chemical profiles, especially in specific and low-represented ingredients. (E)-anethole (4.4%), fenchone (0.5%), and trans-carveol (0.2%) were present only in umbel with seeds, while the β-longipipene (0.5%), (E)-caryophyllene (0.5%), and (2E)-decenal (0.2%) were found only in the stems. The degree of DPPH radical neutralization increased with incubation time. The SFEO isolated from the stems showed stronger antioxidant activity during the incubation times of 20 and 40 min (EC50 value of 5.30 mg/mL and 5.04 mg/mL, respectively) in comparison to the SFEO isolated from the other plant parts. The lowest antioxidant activity was obtained with the SFEO leaves (155.25 mg/mL and 58.30 mg/mL, respectively). This study indicates that SFEO possesses significant antioxidant activities and is animportant component in the food and pharmaceutical industries. It is important to preserve the existing gene pool and biodiversity with rational use SF for the extraction of high-quality essential oils.

Genetic diversity among genotypes of Parkia platycephala (Benth.), a typical tree of northeastern Brazil

Parkia platycephala (Fabaceae) is a useful tree. The leaves are rich in protein, fiber and minerals and are good quality, low-cost fodder for animals, making it a great option for animal feed during the dry season in Northeast Brazil. In addition, wood is used in small buildings and as fuel. With the aim of exploring genetic variation within the species, we have assessed the molecular and morpho-agronomic characteristics of 10 accessions (F1 - F10) of the species originating from the same location and maintained in the Forage Collection at Embrapa Meio Norte. Clustering analyses based on the amplicons generated by 12 inter simple sequence repeat (ISSR) primers and on 36 qualitative/quantitative markers separated the accessions into two groups, the constituents of which were dependent on the characteristics considered. The most divergent genotypes according to ISSR analysis were F3 and F8. Morpho-agronomic analysis identified F2 and F7 as the most divergent, while the traits that contributed most (36.5%) to total diversity were, in order of importance, mature inflorescence length, stem length, immature inflorescence width, seed weight and pedicel length. The results revealed that there is sufficient genetic variability among the studied accessions. These accessions with greater diversity are candidates for actions that promote the conservation, domestication and genetic improvement of the species.

Plant regeneration through somatic embryogenesis in cell suspensions of Cenchrus ciliaris L.

BackgroundThis study aims to establish cell suspension culture, its maintenance and induction of somatic embryogenesis, and in vitro plant regeneration in Cenchrus ciliaris L. Suspension cultures are relatively homogenous cell lines facilitating uniform access to nutrition. These are ideal sources of competent cells for genetic transformation.ResultsCallus was initiated by culturing immature inflorescences of Cenchrus ciliaris cv. IGFRI-3108 on Murashige and Skoog (MS) medium containing 3 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5 mg l−1 6-benzylaminopurine (BAP) with 30 g l−1 sucrose. Cell suspension cultures were established in liquid MS medium using an inoculum size of 10 g l−1. These were maintained to achieve embryogenic cell/regeneration competent cultures. Growth curve analysis and a subculture interval of 20 days were determined to harvest cells at the end of the exponential phase. The cell doubling time was found to be 11 days. Somatic embryogenesis was accomplished in MS medium containing 1 mg l−1 2,4-D, 1 mg l−1 BAP along with growth adjuvants, 300 mg l−1 casein hydrolysate, 400 mg l−1 glutamine and 300 mg l−1 proline. The highest number (16 ± 3.78/per inoculum) of shoots regenerated on this medium. The elongation and rooting of shoots were recorded on basal MS and ½ MS media, respectively. Rooted plants were successfully transferred to pots containing a Soilrite and cocopeat mixture in a 3:1 proportion for 3–4 weeks and later successfully acclimatized in the greenhouse with a 60% survival rate. The genetic fidelity of 12 regenerated plants was analysed using RAPD primers that were genetically identical to the mother plant.ConclusionCell suspension culture-based in vitro plant regeneration of C. ciliaris involved the establishment, maintenance and progression of somatic embryogenesis during shoot and root development. The inherent limitation of callus-mediated in vitro plant regeneration reducing the regeneration potential due to the aging of the calli has been overcome.

Micropropagation of elite date palm (Phoenix dactylifera L.) cultivars Samany and Bertamoda through immature inflorescence explants

Micropropagation of elite date palm (Phoenix dactylifera L.) cultivars Samany and Bertamoda through immature inflorescence explants

Establishment of an Efficient Somatic Embryogenesis Protocol for Giant Reed (Arundo donax L.) and Multiplication of Obtained Shoots via Semi-Solid or Liquid Culture

This study developed an efficient protocol for the in vitro propagation of giant reed (Arundo donax L.) biomass, defining a complete cycle of the induction of somatic embryogenesis from immature inflorescences, followed by the maturation of somatic embryos and the subsequent multiplication of the derived shoots in liquid culture in a temporary immersion system (TIS). The best explants were found to be 30 cm long immature inflorescences, preferably collected in spring. Such an explant type was easy to decontaminate, and the spikelets isolated from it provided over 100 embryogenic callus lines. Among the callus induction media tested, gelled MS medium supplemented with 1.1 mg/L 2,4-D provided the highest percentage of responsive spikelets and the highest density of embryogenic callus. Maturation of the embryogenic callus was easily triggered on gelled MS medium devoid of plant growth regulators. The obtained shoots could be further multiplied on previously optimized gelled DKW medium supplemented with 30 g/L sucrose, 5 mg/L BA, 0.1 mg/L IBA, and 6.8 g/L plant agar. Subsequent high multiplication of the developed shoots was achieved in liquid culture in TIS using a Plantform™ bioreactor, with an immersion cycle of 12 min every 8 h.

Development of an in vitro regeneration system from immature inflorescences and CRISPR/Cas9-mediated gene editing in sudangrass

BackgroundSudangrass (Sorghum sudanense) is a major biomass producer for livestock feed and biofuel in many countries. It has a wide range of adaptations for growing on marginal lands under biotic and abiotic stresses. The immature inflorescence is an explant with high embryogenic competence and is frequently used to regenerate different sorghum cultivars. Caffeic acid O-methyl transferase (COMT) is a key enzyme in the lignin biosynthesis pathway, which limits ruminant digestion of forage cell walls and is a crucial barrier in the conversion of plant biomass to bioethanol. Genome editing by CRISPR/Cas9-mediated mutagenesis without a transgenic footprint will accelerate the improvement and facilitate regulatory approval and commercialization of biotech crops. Methods and resultsWe report the overcome of the recalcitrance in sudangrass transformation and regeneration in order to use genome editing technique. Hence, an efficient regeneration system has been established to induce somatic embryogenesis from the immature inflorescence of two sudangrass cultivars on four MS-based media supplemented with different components. Our results indicate an interaction between genotype and medium composition. The combination of Giza-1 cultivar and M4 medium produces the maximum frequency of embryogenic calli of 80% and subsequent regeneration efficiency of 22.6%. Precise mutagenesis of the COMT gene is executed using the CRISPR/Cas9 system with the potential to reduce lignin content and enhance forage and biomass quality in sudangrass. ConclusionA reliable regeneration and transformation system has been established for sudangrass using immature inflorescence, and the CRISPR/Cas9 system has demonstrated a promising technology for genome editing. The outcomes of this research will pave the road for further improvement of various sorghum genotypes to meet the global demand for food, feed, and biofuels, achieving sustainable development goals (SDGs).

Occurrence of in vitro flowering in coconut (Cocos nucifera L.)

Immature inflorescence with outer spathe length of 5.5 cm size collected from West Coast Tall cultivar of coconut was used as the explant and rachillae bits were inoculated in Y3 media supplemented with 2, 4-D (1 mg L-1). The cultures were incubated in dark for eight months and sub-cultured into the same media at monthly interval. The white shoot like outgrowths formed were sub cultured to ½ MS media fortified with 1 mg L-1 each of NAA and BAP and subsequently transferred to light condition. After three months, the emerging shoot likestructure was transferred to Y3 media fortified with NAA and BAP. Upon developing 3 - 4 leaves, the cultures were transferred to rooting media and root initiation was observed after two months. The transition of vegetative shoot to reproductive state was accompanied by some morphological changes including rapid emergence of long and thin leaves followed by emergence of pearly white inflorescence. Unlike normal inflorescence, the inflorescence emerged was terminal and was devoid of spathe. Prolonged subculture in the same media might have resulted in pH variation and subsequent reduction in organic and inorganicconstituents of the media. The chemical stress experienced by the plantlet might have induced in vitro flowering.

Polyphenolic Compound Variation in Globe Artichoke Cultivars as Affected by Fertilization and Biostimulants Application.

Globe artichoke is an ancient herbaceous plant native to the Mediterranean Basin. The edible part of the plant is limited to the fleshy leaves (bracts) and receptacle of a large immature inflorescence (head) that has been shown to be a rich source of bioactive compounds. Nutritional and pharmacological properties of artichoke heads and leaves are attributed mainly to polyphenolic compounds and inulin present at high concentration. In this study, polyphenols were investigated in two artichoke cultivars (Opal and Madrigal) in response to four nitrogen rates and foliar applications of biostimulating products under drip irrigation. Field experiments were carried out over two growing seasons (2015–2016, 2016–2017) in Policoro (MT), Southern Italy, on a deep clay soil in sub-humid climate conditions. Phenolic compounds were isolated and characterized by means of high-performance liquid chromatography with photodiode array detection and electrospray ionization/mass spectrometry (HPLC-DAD-MS/MS) analysis. In both cultivars, caffeoylquinic acids were more abundant when a dose of 100 kg ha−1 of ammonium nitrate was provided, whereas apigenins were not affected by nitrogen fertilization. Luteolins increased in cv Opal and decreased in cv Madrigal following N fertilization. The application of biostimulants (3 L ha−1) favored the accumulation of polyphenols, in particular of caffeoylquinic acids and apigenin, in artichoke heads in both cultivars. The results obtained highlight some positive aspects related to the synergistic effect of nitrogen fertilization and biostimulant foliar application.

Comparative Analysis of Chemical Composition andAntibacterial and Anti-Inflammatory Activities of theEssential Oils from Chrysanthemum morifolium ofDifferent Flowering Stages and Different Parts

The inflorescence of Chrysanthemum morifolium Ramat., a well-known traditional Chinese herb, has been proved to have a certain inhibitory effect on some bacteria; however, its main components and acne bacteria inhibition effect remain to be elucidated. In this study, GC-MS was used to analyze the components of different flowering stages and different parts and to study the inhibitory effects of six essential oils on S. aureus and P. acnes and their alleviating effects on THP-1 cell inflammation. GC-MS combined with relative retention index method analyzed results stated that the 5 samples of C. morifolium to detect the 124 kinds of volatile components, including (E)-tibetin spiroether, are first detected in the volatile oil of the C. morifolium, and the content of (E)-tibetin spiroether is higher in immature inflorescence of C. morifolium and decreases as it extends its flowering period. Furthermore, the research results of inhibiting common acne-causing bacteria showed that the bacteriostatic effect of essential oils from JH at different flowering stages was better than that from JM and TJ, while the bacteriostatic effect of essential oil from stem and leaf of C. morifolium (SLC) at different parts was better than the roots of C. morifolium (RC). Finally, it was proved that the essential oil from SLC and C. morifolium could alleviate the inflammation of THP-1 cells induced by P. acnes. In conclusion, the antibacterial and anti-inflammatory effects of C. morifolium essential oil may be related to heterospiroolefins compounds, and the antibacterial activity decreases with the prolongation of flowering stage. It was suggested that volatile oil from C. morifolium and SLC could be used as effective components of antibacterial and anti-inflammatory cosmetics.

Micro-RNA-Regulated SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE (SPL) Gene Expression and Cytokinin Accumulation Distinguish Early-Developing Male and Female Inflorescences in Oil Palm (Elaeis guineensis).

Sexual differentiation of inflorescences and flowers is important for reproduction and affects crop plant productivity. We report here on a molecular study of the process of sexual differentiation in the immature inflorescence of oil palm (Elaeis guineensis). This species is monoecious and exhibits gender diphasy, producing male and female inflorescences separately on the same plant in alternation. Three main approaches were used: small RNA-seq to characterise and study the expression of miRNA genes; RNA-seq to monitor mRNA accumulation patterns; hormone quantification to assess the role of cytokinins and auxins in inflorescence differentiation. Our study allowed the characterisation of 30 previously unreported palm MIRNA genes. In differential gene and miRNA expression studies, we identified a number of key developmental genes and miRNA-mRNA target modules previously described in relation to their developmental regulatory role in the cereal panicle, notably the miR156/529/535-SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE (SPL) gene regulatory module. Gene enrichment analysis highlighted the importance of hormone-related genes, and this observation was corroborated by the detection of much higher levels of cytokinins in the female inflorescence. Our data illustrate the importance of branching regulation within the developmental window studied, during which the female inflorescence, unlike its male counterpart, produces flower clusters on new successive axes by sympodial growth.

The effect of nanoparticles of in vitro propagation of seedling male date palm by immature inflorescences

The effect of nanoparticles of in vitro propagation of seedling male date palm by immature inflorescences

Transcriptome analysis of the immature inflorescences of foxtail millet treated with Sq-1 for inducing male sterility

A comparative transcriptomic analysis was carried out through next-generation sequencing technology for the SQ-1-treated immature inflorescences of foxtail millet (Setaria italica). It was found that 96.7% of the pollen of SQ-1-treated plants were sterile, thereby confirming the efficacy of SQ-1 in inducing male sterility in foxtail millet. A total of 6659 DEGs were identified from the plants of 2nd days of treatment, among which 3532 and 3127 were up- and down-regulated, respectively. Comparatively fewer DEGs, 1584 and 2654, were detected from the plants of 4th and 6th days of treatment, respectively. The gene expression profiles of foxtail millet were verified through qRT-PCR in accordance to 16 previously reported genes from other crops that were associated with pollen development. Reference genes Si002651 and Si002929 were found to be the most proper option for SQ-1 treatment. Bangladesh J. Bot. 50(3): 887-894, 2021 (September) Special

Effect of 2,4-Dichlorophenoxy Acetic Acid and Activated Charcoal on Callus Induction of Cocos Nucifera L. Hybrid MATAG Inflorescence

Cocos Nucifera Linn. Var. MATAG is a Dwarf coconut variety that had high demand in Malaysia but low supply. Vegetative propagation of high-yielding MATAG coconut by using in vitro cloning must be considered in contributing to increase coconut productivity. Thus, attempts were made to develop a protocol that would enhance callogenesis as a first preliminary step towards a protocol for mass propagation of C. nucifera L. var. MATAG. The anther isolated from immature inflorescence was used as explants and cultured on modified Eeuwens Y3 media in different concentrations of 2,4-dicholorophenoxy acetic acid (2,4-D) and activated charcoal. The highest callus induction percentage (31.25 ± 12.18) was observed in 20 mg/L 2,4-D. However, 2,4-D at any level tested were not statistically significant. Callus induction media supplemented with 0.5 mg/L activated charcoal gave the highest callusing percentage (25.89 ± 13.59 %) indicating a positive effect of activated charcoal on callusing even though the result obtained not significant compared to control (15.95 ± 6.76 %). But, activated charcoal supplemented in media produced a significant effect compared to control in reducing the percentage of browning. In conclusion, media supplemented with activated charcoal produced a higher rate on callus induction and preventing tissue browning in explant. Besides that, the anther and ovule explant may serve as an efficient explant to study the callus induction of C. nucifera L. var. MATAG and as a basis to screen the potential useful plant growth regulators for somatic embryogenesis.

Metabolomic analysis and antioxidant activity of wild type and mutant chia (Salvia hispanica L.) stem and flower grown under different irrigation regimes.

BACKGROUNDChia (Salvia hispanica L.) is a functional food from Central America. Interest in it is growing rapidly due to the many health benefits from the seed. However, when chia is grown at high latitudes, seed yield may be low whereas a high stem biomass and immature inflorescences are produced. Little is known about the chemical composition and the properties of stems and flowers. In this work, the metabolite profile, the antioxidant activity, and the total polyphenol content of stems and inflorescences were evaluated in a factorial experiment with different chia populations (commercial black chia and long‐day flowering mutants G3, G8, and G17) and irrigation (100% and 50% of evapotranspiration).RESULTSThe results show the influence of irrigation and seed source on the antioxidant activity and total polyphenol content of chia flower and stem. Inflorescences exhibit higher antioxidant activity, suggesting their potential use as natural antioxidant. The mutants G3 and G8, at 50% irrigation, contained the highest amounts of compounds with nutraceutical value, especially within the flower. The mutant G17 showed lower antioxidant activity and polyphenol content compared to other seed sources but exhibited high omega 3 content in flowers but low in stems. This indicates that chia varieties should be chosen according to the objective of cultivation.CONCLUSIONThese findings, indicating a close relation of metabolite content with irrigation and seed source, may provide the basis for the use of chia flower and stem for their nutraceutical value in the food, feed, and supplement industries. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

High-frequency direct somatic embryogenesis and plantlet regeneration from date palm immature inflorescences using picloram

BackgroundDate palm (Phoenix dactylifera L.) is a traditional crop in arid and semi-arid areas. Its vegetative propagation can be achieved by offshoots, but possible number of offshoots in mother palm trees is limited. Micropropagation is a highly recommended strategy for obtaining date palm elite cultivars using shoot tip and immature inflorescences. In this study, micropropagation procedure using inflorescence explants of Medjool cv. is described. For culture initiation, explants from different spathe lengths were cultivated on Murashige and Skoog medium (MS) supplemented with picloram at 1.0 and 2.0 mg/l combined with 2iP at 0.5 mg/l alone and with both 2iP and BA at 0.25 mg/l for 24 weeks. The obtained direct globular embryos were transferred to maturation media with 0.1 mg/l picloram alone or combined with both 2iP and ABA separately and together for further development. Additionally, multiplication and rooting media were optimized by different cytokinins and auxins for high frequency of plantlet production. Acclimatization of in vitro plantlets was also investigated. ResultsThe highest percentage of globular embryo formation was noticed with explants isolated from spathe lengths ranging from 10 to 15 cm. Addition of BA to initiation media with picloram encouraged a significant effect on embryonic culture formation percentage. Incorporation of ABA and 2iP to maturation medium was an effective factor for individual or multiple embryo emergence. Acclimatization of in vitro plantlets having 3–4 roots was successfully accomplished. Irrigation with the full strength solution (MS) encouraged the highest growth vigor degree, leaf number/plant, leaf width, root number, and root thickness degree of ex vitro plants. ConclusionThis research provides an advanced regeneration system for large-scale production of date palm from immature inflorescences of Medjool cv. It opens up the prospects of using picloram with different growth regulators for rapid micropropagation of date palm.

Enhanced somatic embryogenesis and plantlet regeneration in Cenchrus ciliaris L.

A highly reproducible plant regeneration protocol through somatic embryogenesis and shoot organogenesis has been developed for Cenchrus ciliaris. Three explants (seeds, shoot apices, and immature inflorescences) of four genotypes (IG-3108, IG-718, IG-74, and DBC15-8/32/10) were used for callus induction and plant regeneration. The highest rate of callus formation was found using Murashige and Skoog (MS) medium supplemented with 0.5 mg L−1 benzylaminopurine (BA) and 3.0 mg L−1 2,4-dichlorophenoxyacetic acid (2,4-D). The largest number of somatic embryos was generated with the addition of 400 mg L−1 L-proline, 400 mg L−1 L-glutamine, and 300 mg L−1 casein hydrolysate. Somatic embryos were successfully germinated on MS medium with 3.0 mg L−1 BA and 0.25 mg L−1 2,4-D. In vitro plant regeneration was accomplished through somatic embryogenesis using all three explants. Ultra-structural features of somatic embryos confirmed proper formation and ontogeny.

Thidiazuron-induced direct organogenesis from immature inflorescence of three date palm cultivars

BackgroundInflorescence explants of date palm proved to be a promising tool for micropropagation of elite cultivars or rare males and females as organogenesis and somatic embryogenesis could be achieved. These plant materials are abundantly available every year and can be used as cheap and potent explants. Nevertheless, many difficulties could be faced in this protocol according to selection of the spathe size and age, media components, growth regulators, etc. The aim of this study was to determine the influence of various cytokinins on direct organs induction of three date palm cultivars (Selmi, Barhee, and Medjool) from immature inflorescence. An additional objective of this study was to investigate the effect of cytokinins and auxins on growth and development of Medjool cultivar. ResultsVarious combinations of cytokinins were investigated on three date palm inflorescences as N6-(2-isopentenyl) adenine (2iP), kinetin, benzyleadenine (BA), and thidiazuron (N-phenyl-N′-1,2,3-thidiazol-5-yl urea) (TDZ). TDZ alone or in combination with BA proved to be superior for direct organogenesis in all three cultivars so that another combination of TDZ with BA was conducted. Results showed that moderate concentration of BA, with TDZ, gave superior response. Medjool cultivar response surpassed other two cultivars that made the possibility to conduct some growth regulators treatments on its multiplication and regeneration. TDZ at 0.5 + BA at 1.0 mg/l without activated charcoal seemed to enhance multiplication rate. Medium containing 0.5 mg/l of both naphthaleneacetic acid and indole butyric acid in addition to 1.0 mg/l indole acetic acid appeared to be more suitable for rooting stage of Medjool shootlets. ConclusionIn this study, we created an innovation sequence of growth regulators included in nutrient media for date palm direct organogenesis from inflorescence. Organogenesis has been accelerated from immature inflorescence explants and developed to healthy plantlets which acclimatized in greenhouse.

In Vitro Induction of Callus and Flowers in Immature Oil Palm Inflorescences

This work aimed to investigate the effects of different combinations of auxin (0, 225 and 450 µM Picloram) and Murashige and Skoog salts (50% and 100% MS salt concentrations, respectively named as ½ MS and MS) in mediate the induction of callus and flowers from immature inflorescences (developmental stages I-9, I-12 and I-15) of the oil palm BRS – Manicoré hybrid. In I-9 inflorescence explants, the rate of callus induction was 17% higher in ½ MS than in MS; while in both I-12 and I-15 inflorescence explants, callus induction was over than 95% regardless of the MS salt concentration. The higher rate of callus induction in I-9 inflorescences was mediated by 450 µM Picloram, while the callus induction rates for either I-12 or I-15 inflorescences were higher than 92% regardless of Picloram concentration. Floral induction was lower in I-9 inflorescence explants (45% floral induction rate) than in both I-12 and I-15 inflorescence explants (floral induction rate higher than 90%). Our results suggest that Picloram (450 µM) and MS salts concentrations (½ MS) led to the highest rates of calluses and flowers induction in younger inflorescence explants (I-9); however, the medium composition is indifferent on callus and flower induction in I-12 and I-15 inflorescences.