Effect Of Auxin Research Articles

Effects of Auxin at Different Concentrations on the Growth, Root Morphology and Cadmium Uptake of Maize (Zea mays L.)

Indoleacetic acid (IAA) is an important regulator that plays a crucial role in plant growth and responses to abiotic stresses. In the present study, a sand cultivation experiment was carried out to investigate the effects of IAA at different concentrations (0, 0.01, 0.1, 0.5, 1, and 2.5 mmol/L) on maize growth, root morphology, mineral elements (Ca, Mg) and Cd uptake under 20 mg/kg Cd stress. The results showed that 0.01 mmol/L is the optimal IAA concentration for enhancing the Cd tolerance of maize. Compared with the control treatment, 0.01 mmol/L IAA promoted maize growth, with significant increases in the height, shoot and root biomass by 34.6%, 25.0% and 16.3%; altered the root morphology, with increases in root length, root tip number, and root tip density by 8.9%, 31.4% and 20.7%, respectively; and enhanced the mineral element uptake of maize, resulting in signifi- cant increases in the Ca content in shoots and roots by 640.6% and 1036.4% and in the Mg content in shoots by 205.8%, respectively. In addition, 0.01 mmol/L IAA decreased the Cd content and uptake in the shoots by 51.9% and 39.6%, respectively. Furthermore, the Cd content and uptake exhibited a significant negative correlation with Ca content in roots and a significantly positive correlation with root morphology, and the Cd content in shoots was significantly and negatively correlated with root tip number. Thus, 0.01 mmol/L IAA was effective in enhancing the Cd tolerance and plant growth of maize.

Induction and evaluation of secondary metabolite and antioxidant activity in adventitious root of Codonopsis javanica

In this study, the effects of auxin (IBA, NAA), explants, and culture conditions (light/dark) on adventitious root induction of Codonopsis javanica were investigated. The results showed that dark conditions were more suitable for adventitious root induction than light conditions. All three types of explants (internodes, leaves, and nodes) induced adventitious roots, and the appropriate concentration of auxin was 0.5 mg/l IBA. After 4 weeks of incubation under dark conditions, the rooting percentage and number of roots/explant of internode, leaf, and node segments on media supplemented with 0.5 mg/l IBA were 100% and 33.87 roots, 97.78% and 23.48 roots, 100% and 25.20 roots, respectively. These adventitious roots were analysed for the presence of alkaloids, carbohydrates, saponin, fixed oils and fats, phenol, flavonoids, gum, and mucilage. The total polysaccharide content, total phenolic content, and the antioxidant activity (IC50) of C. javanica adventitious root biomass were 16.98%, 1.876 (mg GAE/g DW), and 2.44 (mg/ml), respectively. These results indicate that the adventitious roots of C. javanica contain bioactive compounds, which can be used as a material source for multiplication in large-scale systems.

INFLUENCE OF NITROGEN NUTRITION CONDITIONS AND PHYTHORMONES ON CHANGE OF FATTY ACID COMPOSITION OF VEGETATIVE ORGANS OF SPRING WHEAT TRITICUM AESTIVUM L.

The paper shows the effect of nitrogen nutrition, exogenous auxin, and rhizosphere auxin-synthesizing microorganisms on the variability of the composition of fatty acids (FA) in the vegetative organs of spring wheat. The object of the study was seedlings of spring soft wheat Triticum aestivum L. The determination of FAs was carried out by gas chromatography with mass spectrometry (GC-MS). Analysis of FAs showed that in the control variants (without auxin), nitrogen nutrition conditions did not affect the localization of polyunsaturated FAs in vegetative organs; the maximum content of triene FAs was observed in leaves of 48.30% (N-deficient variant) and 44.8% (NO-3-variant ) and the absence of these FAs in the roots. It was found that in the presence of nitrates, the proportion of unsaturated FAs in the leaves and roots of wheat decreases. The use of exogenous auxin (5–50 μg/ml) in the early stages of ontogenesis leads to an increase in the amount of saturated (palmitic and stearic) acids and a decrease in unsaturated acids in vegetative organs, regardless of the conditions of nitrogen nutrition. During the introduction of spring wheat seedlings by auxin-synthesizing microorganisms, it was noted that nitrogen-fixing bacteria affect the leaves of plants most effectively, the content of saturated FAs increases by 72%, and only 16% increases in these FAs in the leaves of nitrate-reducing microorganisms.

Callus inducement of Toona sinensis: Potential agents against SARS-Corona virus replication

Bioprospecting of anti-SARS-corona virus phytochemical agents is an important issue today as an alternative to chemical drugs whose effectiveness has not been fully successful with no light effect. Quercetin, a component of Toona sinensis young leaves extract, was reported to have anti-viral activity against SARS-corona virus replication in vitro. Currently, the low efficiency of secondary metabolite production is an obstacle. Production of secondary metabolites from callus induction in vitro is considered more efficient and in a short time for commercial applications. The composition of hormones in callus media affects the secondary metabolites formed. The study was conducted to determine the effect of synthetic hormones auxin (BAP) and cytokinin (NAA) on callus percentage, fresh and dry callus cell weight and the average time of callus formation. The call percentage (100%) was obtained in different combinations of BAP and NAA in MS medium. The highest fresh weight of callus (165.50 gL−1) and dry cell weight (28.47 gL−1) were observed in MS medium (1.5 mgL−1 BAP and 1 mgL−1 NAA) within 7 days initial formation time of callus. The results showed that all the indices measured were positively correlated with callus induction in T. sinensis.

Cell surface and intracellular auxin signalling for H+ fluxes in root growth.

Growth regulation tailors development in plants to their environment. A prominent example of this is the response to gravity, in which shoots bend up and roots bend down1. This paradox is based on opposite effects of the phytohormone auxin, which promotes cell expansion in shoots while inhibiting it in roots via a yet unknown cellular mechanism2. Here, by combining microfluidics, live imaging, genetic engineering and phosphoproteomics in Arabidopsis thaliana, we advance understanding of how auxin inhibits root growth. We show that auxin activates two distinct, antagonistically acting signalling pathways that converge on rapid regulation of apoplastic pH, a causative determinant of growth. Cell surface-based TRANSMEMBRANE KINASE1 (TMK1) interacts with and mediates phosphorylation and activation of plasma membrane H+-ATPases for apoplast acidification, while intracellular canonical auxin signalling promotes net cellular H+ influx, causing apoplast alkalinization. Simultaneous activation of these two counteracting mechanisms poises roots for rapid, fine-tuned growth modulation in navigating complex soil environments.

The effect of auxins on amelioration of heat stress‐induced wheat (Triticum aestivum L.) grain loss

AbstractHigh temperature stress during the reproductive growth stage of wheat (Triticum aestivum L.) can cause extensive yield losses. As the plant hormone auxin is a key regulator of reproductive development, we studied the effect of auxins on grain yield in five wheat lines exposed to moderate heat stress (34–35°C) for 6 h per day for 6 days during early flowering (booting stage to anthesis). ‘CDC Go’, a semi‐dwarf (Rht‐B1b) cultivar, responded to auxin application (1 µM) by producing higher grain number and yield under control and heat stress conditions. The effect of five different auxins on grain yield in ‘CDC Go’ was dependent on spike developmental stage at application and position within the spike, with 4‐Cl‐IAA at 1 µM being the most effective auxin treatment. The presence of Rht dwarfing mutant alleles of Rht‐B1 and Rht‐D1 alone did not increase auxin‐induced grain yield when tested in lines isogenic for these alleles. In the field, 4‐Cl‐IAA (1 µM) increased grain yield by 6%–8% only in ‘CDC Go’, one of six hard red spring wheat cultivars tested over two growing seasons in the western Canadian prairies. When 4‐Cl‐IAA application increased grain yield and number, the grain protein content was not affected; when it maintained grain yield in plants with lower biomass, grain protein content was reduced. Our field results suggested that both genotype and environment affect auxin‐induced enhancement of wheat grain yield. We recommend testing target environments with heat stress as a focus of a breeding programme along with further testing of auxin as a crop enhancement tool.

Effect of culture media, auxins and genotypes on plantlet regeneration from oil palm (Elaeis guineensis Jacq.) zygotic embryos through somatic embryogenesis

Aim: This study evaluated efficient culture media for the regeneration of elite material through somatic embryogenesis from oil palm zygotic embryos. Methodology: For callus induction, zygotic embryos of four elite genotypes (G1-264T, G2-238DX17P, G3-37DX17P and G4-237T) were cultured on three basal media (Y3, MS and N6) with different auxin 2 mg l-1 (Picloram, 2,4-D and Dicamba) combinations. Subculture was made every month for three passages. It evaluated various callus characters. The embryogenic calli from callus induction media were transferred to the embryo maturation medium and subcultured until the polyembryoids formed. For shoot and root formation, somatic embryo clumps were transferred into regeneration media. In-vitro plantlets with well-grown roots were hardened in pots for six weeks and assessed clonal fidelity using polymorphic SSR primers. Results: Among the treatments, calli from N6+2,4-D, Y3+2,4-D and N6+Picloram showed the highest embryogenic callus potential. G4-237T induced more embryogenic calli (32.982) among genotypes, which was on par with G1-264T (24.196). Embryogenic calli grown on N6 media with Dicamba showed the highest proliferation rate (1.141). After 60 days of culture on regeneration media, the highest number of plantlets per somatic embryogenic clump was obtained from G1-264T on N6 media supplemented with Dicamba. Interpretation: Culture media salt concentration showed a significant difference among media by causing perturbations of auxin flow during somatic embryogenesis affecting callus induction, proliferation and plantlet regeneration. This may be useful for standardizing the genotype-specific regeneration media in oil palm.

The effects of temperature and exogenous auxin on cutting propagation of some junipers

From past to the present, cultural, medicinal, landscape and culinary use of junipers has contrib­uted to it being one of the most widely distributed woody plants in the world. Therefore, it is so important that finding appropriate production methods to obtain quality seedlings in line with the usage area. In the present study, it was tried to determine the best conditions and applications on propagation by cuttings of three juniper taxa including Juniperus communis L. ‘Hibernica’, Juniperus chinensis L. ‘Stricta’, and Juniperus chinensis L. ‘Stricta Variegata’. For this purpose, two different greenhouse treatments (Greenhouse-1 with the air temperature at 20±2°C, rooting table temperature at 25±2°C and humidity level at 70±2%; Green­house-2 with the air temperature at 20±2°C, rooting table temperature at 20±2°C and humidity level at 70±2%) and different auxin applications (Indole-3-Butyric Acid, Indole-3-Acetic Acid and α-Naphthalene Acetic Acid at concentrations of 3000 and 5000 ppm) were designed. The highest rooting percentages were generally achieved in Greenhouse-1. IAA 5000 ppm treatment for J. communis ‘Hibernica’ (93.33%) and J. chinensis ‘Stricta’ (66.67%, also in Greenhouse-2) and IBA 3000 ppm treatment for J. chinensis ‘Stricta Var­iegata’ (60.00%) showed the best rooting results. This study, in which the best production conditions are investigated in some juniper taxa, is a guiding feature for the producers to ensure the sustainable utilization of junipers.

Root Initiation in Aerial Offshoots of Date Palm (Phoenix dactylifera) by Exogenous Application of Auxins

Date palm (Phoenix dactylifera) is commercially propagated through offshoots. Along with this rooted offshoot the tree also produces aerial offshoots, which are rootless and die after plantation. In this study attempts have been made to evaluate the effect of auxins on the root initiation of the aerial offshoots of date palm cv. Hillawi. Therefore, an experiment was conducted to evaluate the effect of IAA (500 ppm), NAA (500 ppm), alone and in combination on root initiation in aerial offshoots of date palm cv. Hillawi. The auxins were applied to the aerial shoots by injection method. The experiment was laid out according to Randomized Complete Block Design (RCBD) with four treatments (Control, 500pmm IAA, 500ppm NAA and 500ppm IAA+NAA) and each treatment was replicated thrice. Injection method was used to apply the hormones and after the application of auxins the base of each offshoot was wrapped carefully with gunny bags having pinewood shaving as rooting media. After 40 days of supplication, offshoots were detached, and parameters were collected. Data indicated that NAA @ 500ppm gave highest rooting percentage (24.5%), total number of roots per offshoot (82.33) and total weight of roots per offshoots (607.4g) as compared to other treatments. Similarly, a greater number of smaller roots (dia<0.5cm) was also achieved in offshoots treated with 500ppm NAA. Hence, it may be concluded that root initiation was remarkable in NAA alone and in combination with IAA at 500ppm concentration in comparison to other treatments.

Effect of 1-naphthylacetic and indol-3-acetics acid on the intensity of callusogenesis and organogenesis of Linum usitatissimum L. in vitro

Aim. Investigate the effect of auxins of exogenous origin in nutrient medium in vitro on the germination and organogenesis intensity in Linum usitatissimum L. convar. elongatum (‘Hlinum’ variety) at the constant concentration of 6-benzylaminopurine (BAP). Methods. Hypocotyl segments were cultured on Murashige and Skoog nutrient medium supplemented with sucrose (30 g/l) and phytohormones at various concentrations. Other conditions: photoperiod 16 hours, relative humidity 60–80%, air temperature 22–24°C. Results. Common flax has a great capacity to form callus and shoots under the effect of the following factors: 1) only auxins, 2) only cytokines, 3) combinations of auxins and cytokines. Somatic embryogenesis is also possible on a nonhormonal nutrient medium. Conclusions. For somatic embryogenesis in vitro, the optimal concentrations of BAP can be expressed as 1.0 ≤ BAP ≤ 1.75, the optimal concentrations of BAP for the medium supplemented with 1-naphthylacetic (NAA, 0.05 mg/l) 0.5 ≤ BAP ≤ 2.0, the optimal concentration of NAA for the medium supplemented with BAP (1.0 mg/l) 0.025 ≤ NAA ≤ 0.150, and the optimal concentrations of indol-3-acetics acid (IAA) for the medium supplemented with BAP (1.0 mg/l) 0.05 ≤ IAA ≤ 0.50. Keywords: Linum usitatissimum L., in vitro, phytohormones, callus, organogenesis.

Auxin and Cytokinin Interplay during Leaf Morphogenesis and Phyllotaxy.

Auxins (IAA) and cytokinins (CKs) are the most influential phytohormones, having multifaceted roles in plants. They are key regulators of plant growth and developmental processes. Additionally, their interplay exerts tight control on plant development and differentiation. Although several reviews have been published detailing the auxin-cytokinin interplay in controlling root growth and differentiation, their roles in the shoot, particularly in leaf morphogenesis are largely unexplored. Recent reports have provided new insights on the roles of these two hormones and their interplay on leaf growth and development. In this review, we focus on the effect of auxins, CKs, and their interactions in regulating leaf morphogenesis. Additionally, the regulatory effects of the auxins and CKs interplay on the phyllotaxy of plants are discussed.

STIMULASI PERTUMBUHAN Dendrobium sp MENGGUNAKAN HORMON AUKSIN Naphtalena Acetic Acid (NAA) DAN Indole Butyric Acid (IBA)

Dendrobium sp is one type of orchid that is in demand by the public because of the various flower shapes and attractive colors but has a long growth period. Therefore, efforts are needed to accelerate the flowering phase of Dendrobium sp . The purpose of this study was to determine the effect of the hormone auxin in accelerating the growth of Dendrobium sp . The research was carried out using a completely randomized design with a 4x2 factorial pattern with 3 replications. The first factor was the treatment of hormone Auxin NAA (A1) and IBA (A2) then the concentration consisted of 4 levels, namely control (K0); 100 mg/l (K1); 200 mg/l (K2), and 300 mg/l (K3). Observations were made every month variables included plant height, number of leaves, length and width of leaves, number of roots, and length of roots. The results showed that the type and concentration of auxin (Naphthalene Acetic Acid) and (Indole Butyric Acid) interacted to support the growth of leaf length, leaf width, and root length of Dendrobium sp orchids. IBA auxin was more effective in promoting growth and rooting of Dendrobium sp than NAA hormone, the optimal concentration of 200 mg/l until the age of 3 months after acclimatization.

Auxin in Root Development.

Root system architecture is an important determinant of below-ground resource capture and hence overall plant fitness. The plant hormone auxin plays a central role in almost every facet of root development from the cellular to the whole-root-system level. Here, using Arabidopsis as a model, we review the multiple gene signaling networks regulated by auxin biosynthesis, conjugation, and transport that underpin primary and lateral root development. We describe the role of auxin in establishing the root apical meristem and discuss how the tight spatiotemporal regulation of auxin distribution controls transitions between cell division, cell growth, and differentiation. This includes the localized reestablishment of mitotic activity required to elaborate the root system via the production of lateral roots. We also summarize recent discoveries on the effects of auxin and auxin signaling and transport on the control of lateral root gravitropic setpoint angle (GSA), a critical determinant of the overall shape of the root system. Finally, we discuss how environmental conditions influence root developmental plasticity by modulation of auxin biosynthesis, transport, and the canonical auxin signaling pathway.

Comparative proteomic analysis of tomato (Solanum lycopersicum L.) shoots reveals crosstalk between strigolactone and auxin

As one of the main vegetable crops cultivated in the world, the tomato has advantages of high yield and economic benefits, and plays an important role in promoting farmers' income and social and economic growth. However, lateral branches during the growth process of tomato consume considerable nutrients and reduce the yield of tomato. Phytohormones such as strigolactone and auxin can inhibit the formation of lateral branches. However, the mechanism of their interaction is not particularly clear. To better understand the effects of exogenous strigolactone and auxin on tomato, proteome analyses of tomato shoots treated with exogenous GR24 and indole acetic acid were performed using an integrated approach involving tandem mass tag (TMT) labeling and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). We identified 6685 proteins, of which 5822 contained quantitative information. Many differentially expressed proteins (DEPs) were found in different comparisons, including 415, 148, and 130 DEPs in GR24 vs mock, IAA vs mock, and GR24 + IAA vs mock comparisons, respectively. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that ‘photosynthesis - antenna proteins’ were significantly enriched in three treatments. Our data can help reveal the interaction between strigolactone and auxin in tomato seedlings.

Effects of auxin and cytokinin on the regeneration and growth of shoot tomato ( Solanum lycopersicum L.) in drought stress

Tomato is one of the most popular foods in the world. However, drought stress has strongly decreased the growth and yield of tomatoes. Therefore, the study on drought-tolerant tomatoes is essential. In this paper, tomato cultivar TN704, which is popularly grown in Vietnam's Southeast and Vietnam's Mekong Delta was selected. The combination of auxin (IAA, indoleacetic acid) and cytokinin (zeatin) at different concentrations was investigated to determine the effective regeneration media. Then, the drought pretreatment was applied to obtain drought-tolerant shoots. The drought tolerance of regenerated shoots was checked by culture in the drought stress condition after two generations (F1 and F2). The physiological and biochemical changes of regenerated shoots in the drought stress condition were analyzed. The MS 1 2 medium supplemented with 0.2 mg/L IAA and 0.5 mg/L zeatin was the effective medium for in vitro shoot regeneration from tomato leaves. The drought pretreatment (MS 1 2 with 20 g/L mannitol) increased the number of regenerated shoots which can develop in the drought stress condition. The regenerated shoots in the F1 and F2 generations grew strongly under drought conditions. The content of chlorophyll, carotenoid and proline, the intensity of respiration and photosynthesis, and the activity of auxin and cytokinin in leaves of F1 and F2 plant were higher than the control.

Altering maize (Zea mays) seedlings’ growth and lignification processes by action of novel synthesized compounds

Effective management of the course of crop vegetation and adaptation to biotic and abiotic stresses is a prerequisite for stable grain production and requires replenishment of the arsenal of plant growth regulators. The effect of novel synthesized cage amides on maize seedlings morphogenesis has been tested. Seeds of a mid-early maize hybrid 'DN Galatea' after the pre-sowing treatment with 0.01% solutions of test compounds were grown in distilled water. The roots and shoots sections of 10-day-old maize seedlings were stained with phloroglucinol solution to reveal the lignin-containing anatomical structures. The effects of nine different test compounds, exceeding the well-known effects of the phytohormone auxin, promoted the maize seedlings’ linear growth, increased wet weight of roots and shoots, and dry biomass accumulation both in seedlings roots and shoots. Several test compounds activated the dry weight accumulation process without significantly affecting the root and shoot length. In the maize seedlings’ roots, an increase in the diameter and number of the xylem vessels was found, as well as an increase in the lignin-containing layer thickness of the endoderm cells in the root cortex. In the maize seedlings’ shoots, the test compounds caused an increase in the thickness of the lignin-containing outer layer of the seedlings’ first leaf. In general, the test compounds’ effect on seedling roots can potentially enhance root formation; increase efficiency of the roots water-conducting system and the tissues’ strength, thus reducing the likelihood of root lodging in maize plants. The effects of the test compounds revealed in the seedlings’ shoots reflect the activation of the shoots’ structure formation and may have a positive value for enhancing the strength of the plant stems and counteracting the stem lodging of the maize plants.

Effect of Plant Growth Regulators on Protease Activity in Forest Floor of Norway Spruce Stand

Soil proteases are involved in organic matter transformation processes and, thus, influence ecosystem nutrient turnovers. Phytohormones, similarly to proteases, are synthesized and secreted into soil by fungi and microorganisms, and regulate plant rhizosphere activity. The aim of this study was to determine the effect of auxins, cytokinins, ethephon, and chlorocholine chloride on spruce forest floor protease activity. It was concluded that the presence of auxins stimulated native proteolytic activity, specifically synthetic auxin 2-naphthoxyacetic acid (16% increase at added quantity of 5 μg) and naturally occurring indole-3-acetic acid (18%, 5 μg). On the contrary, cytokinins, ethephon and chlorocholine chloride inhibited native soil protease activity, where ethephon (36% decrease at 50 μg) and chlorocholine chloride (34%, 100 μg) showed the highest inhibitory effects. It was concluded that negative phytohormonal effects on native proteolytic activity may slow down organic matter decomposition rates and hence complicate plant nutrition. The study enhances the understanding of rhizosphere exudate effects on soil microbial activity and soil nitrogen cycle.

Auxin guides germ-cell specification in Arabidopsis anthers

Germ cells (GCs) are the key carriers delivering genetic information from one generation to the next. In a majority of animals, GCs segregate from somatic cells during embryogenesis by forming germlines. In land plants, GCs segregate from somatic cells during postembryonic development. In a majority of angiosperms, male GCs (archesporial cells) initiate at the four corners of the anther primordia. Little is known about the mechanism underlying this initiation. Here, we discovered that the dynamic auxin distribution in developing anthers coincided with GC initiation. A centripetal auxin gradient gradually formed toward the four corners where GCs will initiate. Local auxin biosynthesis was necessary for this patterning and for GC specification. The GC determinant protein SPOROCYTELESS/NOZZLE (SPL/NZZ) mediated the effect of auxin on GC specification and modified auxin biosynthesis to maintain a centripetal auxin distribution. Our work reveals that auxin is a key factor guiding GC specification in Arabidopsis anthers. Moreover, we demonstrate that the GC segregation from somatic cells is not a simple switch on/off event but rather a complicated process that involves a dynamic feedback circuit among local auxin biosynthesis, transcription of SPL/NZZ, and a progressive GC specification. This finding sheds light on the mystery of how zygote-derived somatic cells diverge into GCs in plants.

Changes in growth and biochemical parameters in Dunaliella salina (Dunaliellaceae) in response to auxin and gibberellin under colchicine-induced polyploidy.

We reported the significant effect of auxin and gibberellin on mixoploid cultures created by colchicine in Dunaliella salina. Polyploidy induction increased growth and the amount of all biochemical parameters measured in this work including chlorophyll, carotenoid, starch, glycerol, sugar, and protein. Treatment with colchicine 0.1%, which resulted in 58.26% of polyploid cells, had a better effect on increasing the amount of analyzed parameters. Auxin increased the amount of all measured parameters except protein. Low concentrations of auxin (1 and 10µM) caused an increase in growth and the amount of chlorophyll, carotenoid, sugar, starch, glycerol, and protein in the cells treated with colchicine. Gibberellin significantly increased the amount of the mentioned parameters in a concentration-dependent manner. In cultures treated with colchicine, additive effects of gibberellin were observed in glycerol, protein, starch, and sugar content. Our results showed that the use of phytohormones such as auxin and gibberellin can be a good way to increase the biochemical value of algal polyploid cell biomass.

Dynamics of Auxin and Cytokinin Metabolism during Early Root and Hypocotyl Growth in Theobroma cacao.

The spatial location and timing of plant developmental events are largely regulated by the well balanced effects of auxin and cytokinin phytohormone interplay. Together with transport, localized metabolism regulates the concentration gradients of their bioactive forms, ultimately eliciting growth responses. In order to explore the dynamics of auxin and cytokinin metabolism during early seedling growth in Theobroma cacao (cacao), we have performed auxin and cytokinin metabolite profiling in hypocotyls and root developmental sections at different times by using ultra-high-performance liquid chromatography-electrospray tandem mass spectrometry (UHPLC-MS/MS). Our work provides quantitative characterization of auxin and cytokinin metabolites throughout early root and hypocotyl development and identifies common and distinctive features of auxin and cytokinin metabolism during cacao seedling development.