Search Results (11)

This study aimed to evaluate and optimize the effects of three auxin types—indole-3-butyric acid (IBA), naphthaleneacetic acid (NAA), and indole-3-acetic acid (IAA)—applied at four concentrations (1000, 3000, 5000, and 8000 ppm) on the rooting performance of Photinia × fraseri Dress. stem cuttings. The experiment was conducted under controlled greenhouse conditions using a sterile perlite medium. Rooting trays were placed on bottom-heated propagation benches maintained at a set temperature of 25 ± 2 °C to stimulate root formation. However, the actual rooting medium temperature—measured manually every four days from the perlite zone using a calibrated thermometer—ranged between 18 °C and 22 °C, with an overall average of approximately 20 ± 2 °C. The average values of these root-zone temperatures were used in the statistical analyses. Rooting percentage, root number, root length, callus formation, and mortality rate were recorded after 120 days. In addition to classical one-way ANOVA, response surface methodology (RSM) was employed to model and optimize the interactions between auxin type, concentration, and temperature. The results revealed that 5000 ppm IBA significantly enhanced rooting performance, yielding the highest rooting percentage (85%), average root number (5.80), and root length (6.30 cm). RSM-based regression models demonstrated strong predictive power, with the model for rooting percentage explaining up to 92.79% of the total variance. Temperature and auxin concentration were identified as the most influential linear factors, while second-order and interaction terms—particularly T·ppm—contributed substantially to root length variation. These findings validate IBA as the most effective exogenous auxin for the vegetative propagation of Photinia × fraseri Dress. and provide practical recommendations for optimizing hormone treatments. Moreover, the study offers a robust statistical modeling framework that can be applied to similar propagation systems in woody ornamental plants. Full article

Bananas and plantains, belonging to the Musa genus, are important food crops that sustain the livelihoods of countless smallholder farmers globally. However, their production is hindered by various challenges, including abiotic and biotic stresses, climate change, and poor access to clean planting materials, which negatively impact their yields. Addressing these constraints is essential for improving production and ensuring food security. This study investigated the influence of triploid genome background and exogenous growth regulators on the regeneration of Musa cultivars [Gros Michel (AAA genome), Obino l’Ewai and Silk (AAB genome), and Poteau Naine (ABB genome)]. Shoot tip explants of the AAA, AAB, and ABB triploid genomes were cultured in Murashige and Skoog (MS) media supplemented with varying 6-benzylaminopurine (BAP) and indole-3-butyric acid (IBA), indole-3-acetic acid (IAA), or naphthaleneacetic acid (NAA) hormones. Shoot induction was successfully achieved within 21.50 ± 2.00 days, with AAA exhibiting the highest shoot induction frequencies ranging from 30.00 ± 1.57% to 100% and shoot numbers per explant ranging from 3.00 ± 0.50 to 8.80 ± 0.80, followed by the ABB genome ranging from 20.00 ± 3.45% to 100% and from 2.00 ± 0.55 to 5.60 ± 0.50 shoots, and the AAB genome ranging from 17.50 ± 5.01% to 100% and from 2.00 ± 0.04 to 6.60 ± 0.25 shoots, respectively, in media amended with 1.2 to 6.0 mg.L⁻¹ BAP and 0.1 mg.L⁻¹ IAA. The highest rooting rate of 100% was recorded in all three genomes in media containing 1.4 mg.L⁻¹ IBA and 0.5 mg.L⁻¹ IAA, with the AAA genome producing the maximum number of 14.8 roots per explant. The results indicate the positive influence of the AAA genome background on in vitro regeneration and its potential utilization for genomic editing transformation protocols Full article

The natural rooting rate and speed of cuttings of Camellia sinensis var. Assamica cv. Hainan-dayezhong (HD) are relatively low. To investigate the mechanisms by which growth regulators promote adventitious root (AR) formation in this tea variety, this study examined the effects of exogenous indene-naphthaleneacetic acid (ABT-1) and indole-3-butyric acid (IBA) treatments on the AR formation of cuttings, using water as a control. Systematic measurements and comparisons were carried out on the changes and differences in nutrient content, oxidase activity, and endogenous hormone levels and ratios during the AR formation process under the influence of exogenous hormone treatments. The relationships between these factors and the progression of AR formation in HD were analyzed. Both ABT-1 and IBA treatments significantly accelerated the AR formation process and improved the AR formation rate and AR formation index. Among them, IBA treatment showed a more pronounced promoting effect, increasing the AR formation rate by 21.58% and achieving an AR formation index of 32.14% compared with the control. During the AR formation process, both ABT-1 and IBA treatments increased the soluble sugar content and polyphenol oxidase (PPO) activity during the callus induction phase while decreasing peroxidase (POD) and indole-3-acetic acid oxidase (IAAO) activity during the callus induction and adventitious root initiation phases. Additionally, both treatments accelerated the consumption of endogenous hormones such as indole-3-acetic acid (IAA) and abscisic acid (ABA) and amplified fluctuations in cytokinin (CTK) levels and IAA/ABA ratios. Notably, IBA treatment resulted in greater changes in the soluble protein content and IAA/ABA ratio, with an increase of 49.22% and 80.87%, respectively. The two peaks of PPO activity occurred earlier, on days 10 and 40 after cutting, with IBA treatment having 6.85% and 40.35% higher activity than ABT-1 treatment at the corresponding time points, thereby maintaining relatively higher levels throughout callus induction and adventitious root initiation phases. Furthermore, IAAO activity decreased more significantly on days 10 and 30 after cutting, with decreases of 35.45% and 40.75%, respectively, which favored the formation of adventitious roots more. Both treatments promoted AR formation by regulating physiological balance, but IBA demonstrated superior efficacy in accelerating HD cutting rooting. These findings highlight IBA’s potential as a targeted growth regulator for improving HD propagation efficiency. Full article

Cuttage is the main propagation method of tea plant cultivars in China. However, some tea softwood cuttings just form an expanded and loose callus at the base, without adventitious root (AR) formation during the propagation period. Meanwhile, exogenous auxin could promote the AR formation of tea plant cuttings, but the regulation mechanism has not yet explained clearly. We conducted this study to elucidate the regulatory mechanism of exogenous auxin-induced adventitious root (AR) formation of such cuttings. The transcriptional expression profile of non-rooting tea calluses in response to exogenous IBA and NAA was analyzed using ONT RNA Seq technology. In total, 56,178 differentially expressed genes (DEGs) were detected, and most of genes were significantly differentially expressed after 12 h of exogenous auxin treatment. Among these DEGs, we further identified 80 DEGs involved in the auxin induction pathway and AR formation. Specifically, 14 auxin respective genes (ARFs, GH3s, and AUX/IAAs), 3 auxin transporters (AUX22), 19 auxin synthesis- and homeostasis-related genes (cytochrome P450 (CYP450) and calmodulin-like protein (CML) genes), and 44 transcription factors (LOB domain-containing protein (LBDs), SCARECROW-LIKE (SCL), zinc finger protein, WRKY, MYB, and NAC) were identified from these DEGs. Moreover, we found most of these DEGs were highly up-regulated at some stage before AR formation, suggesting that they may play a potential role in the AR formation of tea plant cuttings. In summary, this study will provide a theoretical foundation to deepen our understanding of the molecular mechanism of AR formation in tea cuttings induced by auxin during propagation time. Full article

The aim of this study was to investigate the uptake of exogenously added indole-3-butyric acid (IBA) as an adventitious root (AR) inducer. The concentration of indole-3-butyric acid (IBA) in leafy cuttings of Prunus subhirtella ‘Autumnalis’ from stock material of different physiological ages was analyzed at three evaluation time points (1, 4, 24 h). We examined three stock plants: a physiologically mature stock plant (approximately 60 years old); physiologically rejuvenated plants (16 years old) that were previously propagated by cuttings from semi-mature stock material; and in vitro juvenile stock material. For IBA to effectively induce AR formation, it must first be converted into the active hormone indole-3-acetic acid (IAA). The total concentration of IAA in the first 24 h after cutting was evaluated according to the physiological age of the stock material and the IAA concentration in the cuttings according to the evaluation time points was assessed. We also examined rooting success and the quality of the adventitious root system depending on the physiological age of the stock material. High performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS) was used to identify and quantify the phytohormones. The difference in rooting and quality of the developed AR was observed between semi-mature stock and mature stock material. Cuttings from semi-mature plants rooted in 95.00 ± 5.00% of cases, while cuttings from mature stock plants only rooted in 68.33 ± 4.09%. Successfully rooted cuttings from mature stock material were accompanied by callus formation, which was significantly lower in cuttings from semi-mature stock material. Our results show that the interaction between physiological age and time after severance had no effect on IBA concentration in the cuttings (p = 0.907). Duration of time elapsed since severing (evaluation time points) had a significant effect on the uptake of IBA (p = 0.002 **) and IAA (p = 0.0009 ***) in the cuttings. Physiological age had a significant effect on IAA concentration in the early stages of AR formation in the cuttings (p = 0.038 *). Our results suggest that the dynamics of other endogenous phytohormones and the physiological state of the stock plant are also important for AR formation, as the proportion of successfully rooted cuttings from semi-mature stock material was significantly higher than the proportion of successfully rooted cuttings from mature stock material, irrespective of IBA uptake in stock material of different ages. Full article

The establishment of plant architecture requires coordination of distinct processes including shoot branching and apical dominance (AD). AD involves the bud apical shoot, mainly through indole-3-acetic acid (IAA) synthetized by the cells of the meristem and young leaves. The rootward flow generates an auxin gradient in the stem and buds, regulating lateral bud (LB) outgrowth. Phytochromes and AD are involved in the shade-avoidance syndrome in woody plants. However, the underlying mechanisms remain poorly understood. The aim of this study was to evaluate the sensitivity of cherry rootstocks to light, mediated by the photoreceptor phytochrome, and its effect on the role of auxin in driving branching by AD. Pharmacological treatments using transport inhibitors and a competitor of IAA were applied to transgenic lines of Colt cherry rootstock, which showed different sensitivities to light because of the ectopic expression of a rice phyA gene. Results showed different physiological behaviours among the transgenic lines and between themselves and the Colt-wt line. Exogenous IBA inhibited Colt-wt LB outgrowth, and this inhibition was less intense in transgenic lines. The IAA-inhibitors and IAA-competitor promoted branching. In in vitro phyA-transgenic plantlets, the ectopic gene induced greater branching and a higher number of buds developed in new shoots. This work confirms a positive action of phytochrome on lateral branching in cherry rootstock, playing a role in the regulation of AD. Moreover, we suggest that the confined in vitro system might now be used as a phenotyping screening to test the plasticity of the response, highlighting the behaviour of modified genotypes due to an ectopic insertion event by simple and rapid procedures. Full article

The cuttage rooting method for Acer species is difficult to achieve a good efficacy as trees maintain good characteristics at the rejuvenation stage, thus improving the rooting of Acer species. The addition of exogenous hormones and rejuvenation can improve the rooting effect of cuttings; however, the specific regulatory mechanism is still unclear. Here, Acer mono Maxim rejuvenation and non-rejuvenation cuttings were used as test subjects, to investigate the effects of exogenous hormones on the activities of endogenous hormones and antioxidant enzymes in the rooting process of young cuttings. The results showed that exogenous growth-regulating substances significantly improved the rooting rate of A. mono. Exogenous hormones naphthylacetic acid (NAA) + indolebutyric acid (IBA) increased the initial levels of the endogenous hormones, indoleacetic acid (IAA) and abscisic acid (ABA), and the enzyme activities of peroxidase (POD) and polyphenol oxidase (PPO). Rejuvenation treatment prolonged the time of increase in ABA content and indoleacetic acid oxidase (IAAO) activity at the root primordium induction stage, while increasing trans-zeatin riboside (ZR) content and decreasing POD enzyme activity in cuttings. These results demonstrate that A. mono cuttings can achieve the purpose of improving the rooting rate by adding the exogenous hormone (NAA + IBA), which is closely related to the changes of endogenous hormone content and enzyme activity, and these changes of A. mono rejuvenation cuttings are different from non-rejuvenation cuttings. Full article

Enhancing the capacity of fruit trees to propagate via cuttings is an important endeavor for the high-quality development of the fruit industry. Optimizing the conditions for the cutting propagation of mulberry seedlings is an important factor that influences the industrial production of this plant; however, the currently used mulberry breeding technology system is not mature. In this experiment, an orthogonal design was used to intercept semi-woody shoots of Yueshenda 10 as cuttings and set different hormone concentrations (200, 500, 800, and 1000 mg/L), different hormone types (NAA, IBA, IAA, and ABT-1), and different soaking times (10, 30, 60, and 120 min) for cuttings. The effects of the three factors on the rooting of mulberry cuttings were investigated by soaking the cuttings in clean water for 10 min as a control. The results showed that the primary and secondary order of the three factors affecting the rooting rate of cuttings was hormone concentration > hormone type > soaking time, and the concentration of exogenous hormones had a significant impact on all rooting indicators (p < 0.05). In addition, the rooting rate (66.24%), average number of roots (7.54 roots/plant), and rooting effect index (4.23) of Yueshenda 10 cuttings reached the optimal level when soaked with 800 mg/L ABT-1 for 30 min. The longest root length (10.20 cm) and average root length (4.44 cm) of cuttings achieved the best results when soaked with 800 mg/L NAA for 60 min and 500 mg/L NAA for 30 min, respectively. On balance, it is considered that the preferred solution is to soak the cuttings of Yueshenda 10 with 800 mg/L ABT1 solution for 0.5 h. Full article

Phytohormones play an important role in regulating the maturation process and the quality-related metabolite accumulation of fruits, and their concentration variation has always been concerned during fruit development. However, berry fruits, such as grape berries, are rich in a large number of secondary metabolites, which brings great challenges to the isolation and determination of hormones. In this work, we used grapes as experimental materials and proposed a solid-phase extraction (SPE) protocol to efficiently isolate multiple hormones from phenol-rich matrix using a mixture of dichloromethane, methanol and formic acid as eluent. A highly sensitive method based on ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) was developed to quantify a total of 11 plant growth regulators, including the recognized phytohormones, in grape pericarp and seed. The established method showed satisfactory precision (RSD < 11.3%) and linearity (R² > 0.9980). The limits of detection (LOD) and the limit of quantification (LOQ) were 0.001–0.75 ng/mL and 0.004–2.5 ng/mL, respectively. The recovery for the three levels of analytes spiked ranged from 63% to 118%, and the matrix effect was between 73% and 119%. Finally, the proposed method was applied to investigate the dynamic hormone concentration in Vitis vinifera L. cv. Cabernet Sauvignon berries from different vineyards, and assess the changes in endogenous hormones in grapes after treatment with exogenous growth regulators. We found that the contents of IP, ABA and IAA in pericarp and IP, IAA, IBA and SA in seed were significantly down-regulated after 10 days of treatment with NAA concentrations of 10 mg/L and 40 mg/L. In conclusion, this method helps to elucidate the role played by phytohormones in the maturation process and the accumulation of quality-related metabolites in phenol-rich fruits. Full article

A profile of endogenous hormones and sugars in leaves and pseudobulbs of Laelia anceps subsp. anceps (Orchidaceae) plants induced and non-induced to flowering by the effect of different doses of exogenous gibberellic acid (GA₃), considering the current and back growth structures (CGS and BGS), were investigated. A factorial experiment with five doses of GA₃ and two growth structures was designed. Adult plants with undifferentiated vegetative buds were selected and sprayed with doses of 0, 400, 600, 800, and 1000 mg GA₃ L⁻¹. The main results showed a strong interaction between GA₃ dose and growth structures, which promoted the highest kinetin (KIN) concentration in CGS. Exogenous GA₃ increased endogenous GA₃ in leaves and pseudobulbs induced (I-Leaf and I-PSB) and non-induced (NI-Leaf and NI-PSB) to flowering. For sugar concentration, the 400 mg L⁻¹ GA₃ dose promotes significant interaction with the CGS in NI-PSB. In general, the hormone profile revealed opposite balances of endogenous hormone concentrations for KIN, zeatin (ZEA), trans-zeatin (T-ZEA), indoleacetic acid (IAA), indole-3-butyric acid (IBA) and GA₃, not only for growth structures but also for vegetative organs analyzed, depending on whether the plants were induced or not induced to flowering, with the highest concentration of endogenous hormones in pseudobulbs. Likewise, different sugar concentration balances were observed. These balances of both endogenous hormones and sugars are likely to be involved in the flowering of L. anceps. Full article

A field experiment was conducted using a 3 × 3 orthogonal regression design to explore the growth promotion of one-year-old Yunnan pine seedlings (Pinus yunnanensis Franch.) in response to foliar application of IAA (indole-3-acetic acid) at rates of 0, 200 and 400 mg·L⁻¹ and IBA (indole-3-butyric acid) at rates of 0, 200 and 400 mg·L⁻¹ in order to promote the growth during the seedlings’ early stage. The experiment was conducted at the Lufeng Village Forest Farm of Yiliang County in Kunming, Yunnan, China. The results showed that IAA and IBA were effective in growth promotion of Yunnan pine seedlings. The response of both growth increment and biomass accumulation to the concentration of IAA and IBA can be modeled using a bivariate surface response, and each growth index had a peak value. Growth indexes increased with the increase of the dosage of photohormones before reaching a peak value, and then decreased. The different growth indexes had various responses to the concentrations and ratio of IAA and IBA. The foliar application of IAA in combination with IBA showed the largest improvement on the biomass of the needles, followed by stems and roots. The higher ratio of IAA promoted stem diameter growth, root system development and biomass accumulation in the needles, while a higher ratio of IBA contributed to height growth and biomass accumulation in the stem. Based on the auxin effect equations on the different growth indexes and surface response, the optimum concentrations and the (IAA:IBA) ratios can be obtained. The optimum concentrations of IAA and IBA were 167 and 186, 310 and 217, 193 and 159, 191 and 221, and 206 and 186 mg·L⁻¹, with corresponding ratios of 1:1.11, 1:0.70, 1:0.82, 1:1.15 and 1:0.90, respectively, at the maximum seedling height and collar diameter growth as well as biomass accumulation at the root, stem and needle. The above growth indexes were 22.00%, 79.80%, 48.65%, 82.20% and 107.00% higher than the control treatment. Full article