Root Development Of Seedlings Research Articles

The Effect of Soaking Root Fertilizer on Promoting the Seedling Early Growth and Root Development of Eucalyptus urograndis

We examined the feasibility of applying soaking root fertilizer to Eucalyptus urograndis seedlings by dipping the roots, and the effectiveness of the method for improving the overall growth quality of the seedlings by affecting root growth. The seedlings of E. urograndis in the Southern National Forest Seedling Demonstration Base in China were dipped with seven kinds of soaking root fertilizer formulas, while another group of clear water was set as a control. We regularly investigated the relationship between root traits and other seedling traits, and the formulas conducive to the high-quality growth of seedlings in one month and two months were screened by principal component analysis (PCA). The feasibility of applying soaking root fertilizer by dipping the roots was analyzed by comparing the difference between the formula and the control. The F2 formula had the best promoting effect on the growth and biomass of seedlings and the highest ground diameter within one month. The biomass, cumulative height growth, and average crown width were also the highest in the two months, but the decreasing growth height in F2 was also obvious, along with reduced photosynthesis and root morphology. The F8 and F4 formulas as compound fertilizers showed the potential of a high growth rate and high quality. The seedlings on which they were all applied had an excellent photosynthetic capacity and a well-developed root system. A correlation analysis showed that root traits were significantly correlated with some aboveground indices of seedlings (growth, biomass and nutrients, etc.), among which the root K concentration was very significantly correlated with photosynthetic capacity, and the root P was very significantly correlated with seedling biomass. Dipping roots mainly promoted the uptake of P and K nutrients by roots, which had a positive effect on seedling photosynthesis and the root system, and thus improved the growth increment and growth quality of seedlings. A principal component analysis showed that dipping roots significantly promoted the growth traits of seedlings, and the best-performing formula for dipping roots was F8 at one month of growth. F4 was the best choice for growth at two months. F4 showed excellent performance in all trait indices and was the only treatment where an increase in the rhizome-to-stem ratio occurred, indicating that the nutrient distribution of F4 seedlings was uniform and efficient, which compensated for the deficiency of the follow-up fertility of the quick-acting complex fertilizer. The scientific formula of soaking root fertilizer can be economically applied by dipping roots to synchronously promote early growth and quality of seedlings, which can provide a theoretical basis for the early large-scale cultivation of E. urograndis and other plants.

Regulation of early seedling establishment and root development in Arabidopsis thaliana by light and carbohydrates

Main conclusionRoot development is regulated by sucrose and light during early seedling establishment through changes in the auxin response and chromatin topology.Light is a key environmental signal that regulates plant growth and development. The impact of light on development is primarily analyzed in the above-ground tissues, but little is known about the mechanisms by which light shapes the architecture of underground roots. Our study shows that carbohydrate starvation during skotomorphogenesis is accompanied by compaction of nuclei in the root apical meristem, which prevents cell cycle progression and leads to irreversible root differentiation in the absence of external carbohydrates, as evidenced by the lack of DNA replication and increased numbers of nuclei with specific chromatin characteristics. In these conditions, induction of photomorphogenesis was unable to restore seedling growth, as overall root growth was compromised. The addition of carbohydrates, either locally or systemically by transferring seedlings to sugar-containing medium, led to the induction of adventitious root formation with rapid recovery of seedling growth. Conversely, transferring in vitro carbohydrate-grown seedlings from light to dark transiently promoted cell elongation and significantly reduced root meristem size, but did not primarily affect cell cycle kinetics. We show that, in the presence of sucrose, dark incubation does not affect zonation in the root apical meristem but leads to shortening of the proliferative and transition zones. Sugar starvation led to a rapid increase in lysine demethylation of histone H3 at position K9, which preceded a rapid decline in cell cycle activity and activation of cell differentiation. In conclusion, carbohydrates are required for cell cycle activity, epigenetics reprogramming and for postmitotic cell elongation and auxin-regulated response in the root apical meristem.

Multi-Omics Revealed Peanut Root Metabolism Regulated by Exogenous Calcium under Salt Stress.

High salinity severely inhibits plant seedling root development and metabolism. Although plant salt tolerance can be improved by exogenous calcium supplementation, the metabolism molecular mechanisms involved remain unclear. In this study, we integrated three types of omics data (transcriptome, metabolome, and phytohormone absolute quantification) to analyze the metabolic profiles of peanut seedling roots as regulated by exogenous calcium under salt stress. (1) exogenous calcium supplementation enhanced the allocation of carbohydrates to the TCA cycle and plant cell wall biosynthesis rather than the shikimate pathway influenced by up-regulating the gene expression of antioxidant enzymes under salt stress; (2) exogenous calcium induced further ABA accumulation under salt stress by up-regulating the gene expression of ABA biosynthesis key enzymes AAO2 and AAO3 while down-regulating ABA glycosylation enzyme UGT71C5 expression; (3) exogenous calcium supplementation under salt stress restored the trans-zeatin absolute content to unstressed levels while inhibiting the root cis-zeatin biosynthesis.

Overexpression of peanut (Arachis hypogaea L.) AhGRFi gene enhanced root growth inhibition under exogenous NAA treatment in Arabidopsis thaliana.

The 14-3-3 protein is a kind of evolutionary ubiquitous protein family highly conserved in eukaryotes. Initially, 14-3-3 proteins were reported in mammalian nervous tissues, but in the last decade, their role in various metabolic pathways in plants established the importance of 14-3-3 proteins. In the present study, a total of 22 14-3-3 genes, also called general regulatory factors (GRF), were identified in the peanut (Arachis hypogaea) genome, out of which 12 belonged to the ε group, whereas 10 of them belonged to the non- ε-group. Tissue-specific expression of identified 14-3-3 genes were studied using transcriptome analysis. The peanut AhGRFi gene was cloned and transformed into Arabidopsis thaliana. The investigation of subcellular localization indicated that AhGRFi is localized in the cytoplasm. Overexpression of the AhGRFi gene in transgenic Arabidopsis showed that under exogenous 1-naphthaleneacetic acid (NAA) treatment, root growth inhibition in transgenic plants was enhanced. Further analysis indicated that the expression of auxin-responsive genes IAA3, IAA7, IAA17, and SAUR-AC1 was upregulated and GH3.2 and GH3.3 were downregulated in transgenic plants, but the expression of GH3.2, GH3.3, and SAUR-AC1 showed opposite trends of change under NAA treatment. These results suggest that AhGRFi may be involved in auxin signaling during seedling root development. An in-depth study of the molecular mechanism of this process remains to be further explored.

Theanine, a tea-plant-specific non-proteinogenic amino acid, is involved in the regulation of lateral root development in response to nitrogen status.

Glutamine synthetase type I (GSI)-like proteins are proposed to mediate nitrogen signaling and developmental fate by synthesizing yet unidentified metabolites. Theanine, the most abundant non-proteinogenic amino acid in tea plants, is the first identified metabolite synthesized by a GSI-like protein (CsTSI) in a living system. However, the roles of theanine in nitrogen signaling and development are little understood. In this study we found that nitrogen deficiency significantly reduced theanine accumulation and increased lateral root development in tea plant seedlings. Exogenous theanine feeding significantly repressed lateral root development of seedlings of tea plants and the model plant Arabidopsis. The transcriptomic analysis revealed that the differentially expressed genes in the roots under theanine feeding were enriched in the apoplastic pathway and H2O2 metabolism. Consistently, theanine feeding reduced H2O2 levels in the roots. Importantly, when co-treated with H2O2, theanine abolished the promoting effect of H2O2 on lateral root development in both tea plant and Arabidopsis seedlings. The results of histochemical assays confirmed that theanine inhibited reactive oxygen species accumulation in the roots. Further transcriptomic analyses suggested the expression of genes encoding enzymes involved in H2O2 generation and scavenging was down- and upregulated by theanine, respectively. Moreover, the expression of genes involved in auxin metabolism and signaling, cell division, and cell expansion was also regulated by theanine. Collectively, these results suggested that CsTSI-synthesized theanine is likely involved in the regulation of lateral root development, via modulating H2O2 accumulation, in response to nitrogen levels in tea plants. This study also implied that the module consisting of GSI-like protein and theanine-like metabolite is probably conserved in regulating development in response to nitrogen status in plant species.

Forward to the second special seedling root development

Forward to the second special seedling root development

QTL mapping for early root and shoot vigor of upland rice (Oryza sativa L.) under P deficient field conditions in Japan and Madagascar.

Upland rice production is limited by the low phosphorus (P) availability of many highly weathered tropical soils and P deficiency is likely to become increasingly limiting in future drier climates because P mobility decreases sharply with soil moisture. Good seedling root development will be crucial to cope with the combined effects of low P and water availability. Upland rice genebank accession DJ123 was used as a donor for P efficiency and root vigor traits in a cross with inefficient local variety Nerica4 and a set of backcross lines were used to characterize the seedling stage response of upland rice to low P availability and to identify associated QTL in field trials in Japan and Madagascar. Ten QTL were detected for crown root number, root, shoot and total dry weight per plant in a highly P deficient field in Japan using the BC1F3 generation. Of these, qPef9 on chromosome 9 affected multiple traits, increasing root number, root weight and total biomass, whereas a neighboring QTL on chromosome 9 (qPef9-2) increased shoot biomass. Field trials with derived BC1F5 lines in a low-P field in Madagascar confirmed a highly influential region on chromosome 9. However, qPef9-2 appeared more influential than qPef9, as the shoot and root biomass contrast between lines carrying DJ123 or Nerica4 alleles at qPef9-2 was +23.8% and +13.5% compared to +19.2% and +14.4% at qPef9. This advantage increased further during the growing season, leading to 46% higher shoot biomass at the late vegetative stage. Results suggest an introgression between 8.0 and 12.9 Mb on chromosome 9 from P efficient donor DJ123 can improve plant performance under P-limited conditions. The QTL identified here have practical relevance because they were confirmed in the target genetic background of the local variety Nerica4 and can therefore be applied directly to improve its performance.

Effect of Different Peat Substitute Substrates on the Growth and Quality of Seedlings of Handroanthus chrysanthus (Jacq.) S.O. Grose

With the depletion of peat resources, local agricultural and forestry wastes represent potential seedling substrate materials. We investigated the effects of mixed substrates supplemented with peat replacements, such as decomposed eucalyptus bark, coconut bran, and carbonized rice husk, on the growth of Handroanthus chrysanthus (Jacq.). We screened suitable organic substrates for the production of seedlings of H. chrysanthus to provide a theoretical basis for its scientific cultivation. The proportions of 15 types of substrates were determined by using simplex center-of-gravity mixing. The physical properties of different mixed substrates were studied, and the growth, biomass, root development, and photosynthesis of seedlings were analyzed. The quality of seedlings was comprehensively evaluated, and the optimal substrate ratio was obtained through regression analysis. Substrate compositions had significantly different effects on growth, biomass, root morphology, and photosynthesis. The results of these single-index analyses were corroborated by using principal component analysis. Adding decomposed eucalyptus bark was beneficial to the growth of seedlings, whereas coconut bran and perlite restricted growth. The results show that decomposed eucalyptus bark can replace peat as a container seedling substrate. The substrate formula can be used to provide technical support and a theoretical basis for the scientific cultivation of high-quality light matrix seedlings of H. chrysanthus.

Preferences of Pinus sylvestris seedling roots for different phosphorus sources under phosphorus-deficient conditions

PurposePhosphorus (P) is a limiting nutrient in many managed forests. To further understand the risks and benefits of biochars as sustainable P source in forest management, an improved mechanistic understanding of its interactions in root systems is required.MethodsA rhizobox experiment was conducted to observe root response of P. sylvestris (Scots pine) seedlings to different biochars in comparison to triple superphosphate (TSP) fertiliser as a P source. Three types of wood-derived biochar were compared: biochar from mixed softwood pellets (“Reference biochar”); from the vascular cambium zone of Picea sitchensis (“VCZ biochar”) and from mixed softwood pellets infused with TSP (“Processed biochar”). These biochars presented a range of available P from low to high. Seedling root development was spatially analysed using GIS software.ResultsThe total length of P. sylvestris roots did not significantly differ between treatments. However, seedling roots showed strong preference for soil proximal to VCZ biochar and strong avoidance to TSP fertiliser. There was a milder avoidance effect for Processed biochar. Differences in root responses could be explained by available P: roots favored a moderate, sustained P source and avoided high available P sources. The avoidance effect can be attributed partially to lower soil pH around TSP fertiliser.ConclusionThe extent concentration and duration of P availability affects the root response of P. sylverstris to P sources. Under P-deficient conditions, P. sylvestris root growth was markedly improved by introducing biochar with a certain P concentration, and VCZ biochar has potential as an effective source of P in forest establishment.

Evaluation of colonization and mutualistic endophytic symbiosis of Escherichia coli with tomato and Bermuda grass seedlings.

Escherichia coli is generally considered a bacterium associated with animal microbiomes. However, we present evidence that E. coli may also mutualistically colonize roots of plant species, even to the extent that it may become endophytic in plants. In this study we used GFP tagged E. coli to observe its colonization and effects on tomato (Solanum lycopersicum) and Bermuda grass (Cynodon dactylon) seedling development and growth. Inoculation with the bacterium significantly improved root development of both seedlings tested. Treatment also increased the photosynthetic pigments in Bermuda grass seedlings. However, effects on shoot length in both seedlings were not significant. This bacterium was found to produce indole acetic acid (IAA) up to 8.68 ± 0.43 µg ml−1 in the broth medium amended with tryptophan. Effects on seedling root growth could, in part, be explained by IAA production. Bacteria successfully colonized the root surfaces and interiors of both seedlings. Tagged bacteria expressing the GFP were observed in the vascular tissues of Bermuda grass seedling roots. Seedlings with bacteria showed greater survival and were healthier than seedlings without bacteria, indicating that E. coli set up a successful mutualistic symbiosis with seedlings. E. coli is not commonly considered to be a plant endophyte but is more generally considered to be a crop contaminant. In this study we show that E. coli may also be an endophyte in plant tissues.

The miR164-TaNAC14 module regulates root development and abiotic-stress tolerance in wheat seedlings

Previous studies have revealed the miR164 family and the miR164-targeted NAC transcription factor genes in rice (Oryza sativa) and Arabidopsis that play versatile roles in developmental processes and stress responses. In wheat (Triticum aestivum L.), we found nine genetic loci of tae-miR164 (tae-MIR164 a to i) producing two mature sequences that down-regulate the expression of three newly identified target genes of TaNACs (TaNAC1, TaNAC11, and TaNAC14) by the cleavage of the respective mRNAs. Overexpression of tae-miR164 or one of its target genes (TaNAC14) demonstrated that the miR164-TaNAC14 module greatly affects root growth and development and stress (drought and salinity) tolerance in wheat seedlings, and TaNAC14 promotes root growth and development in wheat seedlings and enhances drought tolerance, while tae-miR164 inhibits root development and reduces drought and salinity tolerance by down-regulating the expression of TaNAC14. These findings identify the miR164-TaNAC14 module as well as other tae-miR164-regulated genes which can serve as new genetic resources for stress-resistance wheat breeding.

Biocarvão e bioestimulante na formação de mudas de Schinus terebinthifolius

ABSTRACT The use of new products, such as biochar and biostimulants, has the potential to accelerate growth and improve the quality of seedlings that will be taken to the field. Therefore, this study aimed to evaluate the influence of biochar and plant biostimulant on the formation of Schinus terebinthifolius seedlings. The experiment was installed in randomized blocks arranged in a 5 × 2 factorial scheme with four replications. Biochar proportions in the substrate composition (0, 7.5, 15, 22.5 and 30%) in the presence (15 mL L-1) or absence of biostimulant in the seed treatment were evaluated. Stem diameter, height, leaf area, root length and volume, and shoot and root dry mass were measured at 100 days after sowing. Relationships were calculated from these parameters, which determine the quality of seedlings. The combined use of biochar and biostimulant influences the formation and quality of Schinus terebinthifolius seedlings, with this association being beneficial for the root development of seedlings. Biochar is viable and may be added to the substrate mixture for producing S. terebinthifolius seedlings. The proportions containing around 15% of biochar presented seedlings with the highest quality. The use of biostimulant allows for adding higher quantities of biochar to be mixed in the substrate. Taller plants have larger stem diameters and root lengths. Plants with larger root volumes provide better seedling quality, evidenced by the higher Dickson quality index.

Root and shoot development of corn seedlings as affected by rhizobacteria

Multifunctional microorganisms are beneficial microorganisms able of promoting plant growth through direct and indirect mechanisms. Because of this, has enormous potential for use when aiming a sustainable agriculture. The objective of this work was to determine the effect of seed inoculation with multifunctional microorganisms on the initial development of corn seedlings. The experiment was carried out under controlled conditions in a completely randomized design, with seven treatments and six replications. Treatments consisted of microbiolization of corn seeds with the rhizobacteria: 1. Burkholderia cepacea (BRM 32111), 2. Serratia marcenses (BRM 32113), 3. Serratia sp. (BRM 32114), 4. Bacillus sp. (BRM 63573), 5. Azospirillum brasilense (Ab-V5), 6. Azospirillum sp. (BRM 63574) and 7. control treatment (no microorganisms). For each experimental unit, 500 mL plastic pots filled with soil and two corn seeds were used. After 14 days the seedlings were removed from the pots, set aside from the ground and photographed with a digital camera. The images presented were analyzed by WinRHIZO 2012 software to determine: total root length, root diameter, total root surface area and root volume. After this, roots and shoots of the seedlings were dried and weighed. Corn seedlings treated with the multifunctional microorganisms Bacillus sp. (BRM 63573), Serratia sp. (BRM32114) and Azospirillum sp. (BRM 63574) presented increased in the root and shoots biomass compared to untreated seeds. The microorganism Azospirillum sp. (BRM 63574) was the one that provided the highest values in the parameters of total root length, root diameter, root volume, root dry mass, shoot dry mass and total dry mass compared to the control treatment. The use of multifunctional microorganisms is a promising alternative to provide greater development of corn seedlings.

Effects of Phosphorus on Growth and Development of Soybean Seedlings

Soybean seedlings were treated with different phosphorus (P) concentrations for 20 days to investigate their growth and development. The root growth and development of soybean seedlings was the best when the concentration of phosphorus was 250 μmol/L. After 20 days of cultivation at this concentration, the roots of soybean seedlings were developed, indicating that the main root length, lateral root length, and the number of lateral root was the best among all treatments, and the number of lateral roots was quite a few. In addition, when the concentration of P was at 250 μmol/L, it had a better promotion effect on the plant height of soybean seedlings, and could significantly enhance the development of soybean seedlings. Moreover, the growth of soybean seedlings would be inhibited at the condition of phosphorus deficiency or excessive phosphorus. In this experiment, the growth indexes of soybean seedlings were compared between four treatments of phosphorus concentration, so as to make a basic study on the physiological effect of soybean on phosphorus in early stage.

X‐ray CT reveals 4D root system development and lateral root responses to nitrate in soil

AbstractThe spatial arrangement of the root system, termed root system architecture, is important for resource acquisition as it directly affects the soil zone explored. Methods for phenotyping roots are mostly destructive, which prevents analysis of roots over time as they grow. Here, we used X‐ray microcomputed tomography (μCT) to non‐invasively characterize wheat (Triticum aestivum L.) seedling root development across time under high and low nitrate nutrition. Roots were imaged multiple times with the 3D models co‐aligned and timestamped in the architectural plant model OpenSimRoot for subsequent root growth and nitrate uptake simulations. Through 4D imaging, we found that lateral root traits were highly responsive to nitrate limitation in soil with greater lateral root length under low N. The root growth model using all μCT root scans was comparable to a parameterized model using only the final root scan in the series. In a second μCT experiment, root growth and nitrate uptake simulations of candidate wheat genotypes found significant root growth and uptake differences between lines. A high nitrate uptake wheat line selected from field data had a greater lateral root count and length at seedling growth stage compared with a low uptake line.

LED lighting stimulates root development and height in corn seedlings

The use of LED technology advances rapidly in different fields of agricultural sciences, among others to generate stimulating effects to the physiological development of exposed plants. The objective of the present study was to characterize the physiological response to photoperiod with LED light in corn plants. Four genotypes and four photoperiod treatments were evaluated with LED lighting (white, blue, green, red). The experimental design was randomly complete blocks with three repeats, the treatments were the combination of genotypes and light spectra. The response variables were: height, stem diameter, radicle length, radicle volume and leaf area. The data were analyzed by ANOVA, running a multiple comparison test of means by Tukey. The results showed similarity in the behavior of LED light in some variables, while in the genotypes there was a different interaction before each treatment. For physiological stimulation it was obtained that, blue LED improves root quality (absorbent capillaries and water storage content) in the B1G, RG and B2G genotypes, while the red LED in the WG, B1G and B2G genotypes and in the green LED the B1G, RG and B2G materials, stimulated the vegetative growth of stem in the seedling respectively.

Effects of Root Zone Warming on Maize Seedling Growth and Photosynthetic Characteristics Under Different Phosphorus Levels.

Phosphorus content and root zone temperature are two major environmental factors affecting maize growth. Both low phosphorus and root zone high temperature stress significantly affect the growth of maize, but the comprehensive effects of phosphorus deficiency and root zone warming are less studied. This study aimed to explore the effects of phosphorus deficiency and root zone warming on the root absorption capacity, total phosphorus content, and photosynthetic fluorescence parameters of maize seedlings. The results showed that maize shoots and roots had different responses to root zone warming and phosphorus deficiency. Properly increasing the root zone temperature was beneficial to the growth of maize seedlings, but when the root zone temperature was too high, it significantly affected the root and shoot development of maize seedlings. The root zone warming had a more significant impact on the root system, while phosphorus deficiency had a greater impact on the shoots. Phosphorus content and root zone warming had a strong interaction. Under the comprehensive influence of normal phosphorus supply and medium temperature in the root zone, the growth of maize seedlings was the best. Under the combined effects of low phosphorus and high temperature in the root zone, the growth was the worst. Compared with the combination of normal phosphorus and root zone medium temperature treatment, the dry mass of the low-phosphorus root zone high temperature treatment was decreased by 55.80%. Under the condition of low-phosphorus too high root zone temperature reduced root vitality, plant phosphorus content, which in turn affected plant growth and light energy utilization efficiency. In the case of sufficient phosphate fertilizer supply, appropriately increasing the soil temperature in the root zone is beneficial to increase the absorption and utilization of phosphorus by plants and promote the growth and development of maize seedlings.

A review on the potential of empty fruit bunch (EFB) compost as growing medium for oil palm seedling production

The oil palm industry is among the important sectors in Malaysia. The productions of palm oil keep increasing year by year due to high demand from other countries, generating an abundance of wastes from the field and the mill. These wastes may significantly affect the environment. Composting is one of the methods to reduce the volume of waste. The compost material is widely used especially in agriculture activities due to its properties which have been enhanced during the composting process. Empty fruit bunch (EFB) compost mostly returns to the soil as mulch to conserve soil moisture and acts as organic fertilizer since it contains high nutrients needed by the plant. Currently, the depletion of fertile soil leads to less availability of growing medium, especially in the nursery. The properties of the growing medium are important to ensure better root development of seedlings and subsequently affect the overall plant growth. Therefore, numerous studies have been conducted to identify the suitable growing medium as a substitute for topsoil which is currently limited to raising seedlings in the nursery. This review examines the current methods of composting EFB and provides summarized research information on the effect of EFB compost on oil palm seedling growth. The oil palm wastes that are properly managed could produce value-added by-products and promotes sustainable agriculture practices.

Substrates, emergence and initial development of passion fruit seedlings

The propagation of any crop is understood as a crucial step for the success of the crop, being the main form of propagation of passion fruit to sexual, where almost all cases of commercial plantations, orchards are formed from seedlings generated from seeds produced in substrates. The objective was then to evaluate the effect of different substrates on the emergence and initial development of passion fruit (Passiflora edulis) seedlings. The experimental design was a randomized block with 6 treatments and 4 repetitions with 25 seeds per experimental unit. The seeds were submitted to the treatments, sown in different substrates, being: T1 = Pure soil (100%); T2 = Soil (75%) + humus (25%); T3 = Soil (75%) + bovine manure (25%); T4 = Soil (75%) + chicken manure (25%); T5 = Soil (75%) + Natufert® organomineral fertilizer (25%); T6 = Soil (75%) + coffee straw (25%). Thirty days after sowing the variables were evaluated, percentage of germination. Sixty days after sowing were evaluated: number of leaves; plant height; collection diameter; root length; leaf green mass; leaf dry mass; green root mass; dry root mass. The treatment Terra (75%) + coffee straw (25%) proved to be the most recommended with regard to variables of the aerial part, while Terra (75%) + humus (25%) and Terra (75%) + bovine manure (25%) were the most suitable for the root development of seedlings.

Spatiotemporal regulation of JAZ4 expression and splicing contribute to ethylene- and auxin-mediated responses in Arabidopsis roots.

Jasmonic acid (JA) signaling controls several processes related to plant growth, development, and defense, which are modulated by the transcription regulator and receptor JASMONATE-ZIM DOMAIN (JAZ) proteins. We recently discovered that a member of the JAZ family, JAZ4, has a prominent function in canonical JA signaling as well as other mechanisms. Here, we discovered the existence of two naturally occurring splice variants (SVs) of JAZ4 in planta, JAZ4.1 and JAZ4.2, and employed biochemical and pharmacological approaches to determine protein stability and repression capability of these SVs within JA signaling. We then utilized quantitative and qualitative transcriptional studies to determine spatiotemporal expression and splicing patterns invivo, which revealed developmental-, tissue-, and organ-specific regulation. Detailed phenotypic and expression analyses suggest a role of JAZ4 in ethylene (ET) and auxin signaling pathways differentially within the zones of root development in seedlings. These results support a model in which JAZ4 functions as a negative regulator of ET signaling and auxin signaling in root tissues above the apex. However, in the root apex JAZ4 functions as a positive regulator of auxin signaling possibly independently of ET. Collectively, our data provide insight into the complexity of spatiotemporal regulation of JAZ4 and how this impacts hormone signaling specificity and diversity in Arabidopsis roots.