Search Results (15)

Tropical water lilies are a group of aquatic plants with high ornamental value and are widely favored in home gardening. However, most tropical water lily cultivars feature a large plant stature and vigorous spreading growth layout, making them unsuitable for cultivation in small containers. Therefore, developing miniaturization cultivation techniques for tropical water lilies in small containers is required. Plant growth retardants are effective in inducing plant dwarfing and overall miniaturization. In this study, the tropical water lily cultivar ‘Black Beauty’ was used as the experimental material to explore the effects of two plant growth retardants, chlormequat chloride (CCC) and paclobutrazol (PP₃₃₃), on its growth and development, with the objective of screening optimal retardant types, application concentrations and treatment methods. The results showed that the growth rate of ‘Black Beauty’ slowed down under either CCC or PP₃₃₃ treatment, and remained stable from day 21 to day 51. Compared with the control group, treated plants presented reduced crown spread, decreased leaf area and thickened leaves; the number of flowers and leaves declined slightly, and the key ornamental morphological traits (compact plant form, moderate leaf size, normal flowering) were maintained. PP₃₃₃ exhibited a stronger dwarfing effect than CCC. When the plant growth retardants were dissolved in water for application, a 6-day treatment interval delivered better dwarfing efficacy than a 9-day interval. Among all treatments, 30 mg·L⁻¹ PP₃₃₃ applied at 6-day intervals achieved the optimal miniaturization effect. Following this treatment, the endogenous accumulation of chlorophyll, soluble protein and total sugar, together with the activity levels of antioxidant enzymes (SOD, POD, CAT), were markedly higher than those measured in the control and all other treatment groups, whereas the endogenous accumulation of malondialdehyde (MDA) decreased substantially. The contents of endogenous hormones IAA, GA₃ and ZR in all treatment groups decreased with the increase in retardant concentration, whereas the ABA content showed an upward trend. The 30 mg·L⁻¹ PP₃₃₃ treatment applied every six days induced the minimal endogenous accumulation of IAA, GA₃ and ZR, alongside the maximum endogenous ABA accumulation within plant tissues. For potted cultivation of ‘Black Beauty’ water lily, it is recommended to apply 30 mg·L⁻¹ PP₃₃₃ at 6-day intervals and use containers with an outer diameter of 30–35 cm. Full article

A novel cucumber pulp certified reference material (CRM) was prepared for the analysis of plant growth regulator residues, specifically chlormequat chloride (CCC) and 2,4-dichlorophenoxyacetic acid (2,4-D). The matrix CRM candidates were prepared by cucumber pulping, spiking, homogenizing and subpackaging. A reference method of liquid chromatography tandem isotope dilution mass spectrometry (ID-LC-MS/MS) was established for simultaneous measurement of mass fractions of CCC and 2,4-D in cucumber pulp. Interlaboratory value assignment of CCC and 2,4-D in the cucumber pulp CRM was performed using the ID-LC-MS/MS method. The certified values with expanded uncertainties (coverage factor k = 2) were assigned to be 4.1 mg/kg ± 0.4 mg/kg for CCC, 2.0 mg/kg ± 0.2 mg/kg for 2,4-D. Homogeneity assessment was performed on fifteen randomly selected units, and statistical analysis confirmed the CRM’s homogeneity for both CCC and 2,4-D, both between and within packages. The long-term stability of the CRM at −20 °C storage condition and short-term stability at 30 °C were monitored for 14 months and nine days, respectively, and no significant trend differences were observed. The uncertainty contributions from characterization, homogeneity and stability were taken into account in uncertainty evaluation. The CRM was officially certified and registered under the number GBW(E)100932 by the State Administration for Market Regulation of the P. R. China. Full article

Lodging is one of the key limiting factors in achieving high wheat yield. The application of plant growth retardants (PGRts) is regarded as an effective practice to prevent lodging. For accurate PGRt selection and the establishment of stable, high-yield production plans, it is essential to make clear the regulation strategies for lodging resistance and yield in PGRts. Field experiments were conducted at two test sites. At the initial jointing stage of wheat, Chlormequat Chloride (CCC) or Uniconazole (S₃₃₀₇) was sprayed. Compared with the control (CK), spraying CCC or S₃₃₀₇ significantly reduced the culm lodging index (CLI) and decreased the lodging rate from 7.1% to 15.6%. CCC was more capable of adjusting plant morphology (reducing plant height and second internode length and increasing stem diameter), while S₃₃₀₇ was more effective in enhancing breaking strength. The contents of GA, IAA, and zeatin nucleoside (ZR) and the activities of lignin-related enzymes (TAL and CAD) were significantly correlated with different stem indicators and CLI. Compared with CK, the yield after spraying CCC or S₃₃₀₇ increased by 6.5% and 6.0%, respectively. CCC mainly enhanced the yield by increasing grain weight per spike and the SPAD value of leaves, while S₃₃₀₇ mainly did so by increasing the number of spikes and the effective leaf area. Moreover, carbon metabolism-related enzymes (Rubisco, SS, and SPS) were significantly positively correlated with the yield. The enzyme activity of CCC was higher at the heading stage, while that of S₃₃₀₇ was higher at the filling stage. Hence, spraying CCC or S₃₃₀₇ can significantly enhance lodging resistance and yield. The optimal PGRts should be selected based on the climate and the growth stage of the wheat. Full article

Excessive shoot vigor in grapevines negatively impacts plant growth and fruit quality, necessitating the use of plant growth regulators (PGRs) for canopy management. This study investigated the effects of mepiquat chloride (MC) and chlormequat chloride (CCC) on shoot growth (including new shoot length, relative chlorophyll content, leaf area, etc.) and fruit quality in Vitis vinifera cv. ‘Shine Muscat’. Different concentrations of MC (100, 300, 500, 700 mg/L) and CCC (100, 300, 500, 700 mg/L) were applied via foliar spraying at multiple stages before flowering. The results demonstrated that both PGRs effectively suppressed shoot elongation, with CCC exhibiting superior inhibitory efficacy compared to MC. However, high concentration of either compound also restricted leaf and cluster development. Optimal treatments MC (500 mg/L) and CCC (100 mg/L) significantly enhanced berry size, soluble solids content (SSC), and solid–acid ratio while maintaining effective shoot control. For practical application, we recommend spraying MC (500 mg/L) or CCC (100 mg/L) during the new shoot growth, flower-cluster separation, and flowering stages of ‘Shine Muscat’ grapevines to improve the new shoot control effect and fruit quality. Full article

Chlormequat chloride (CCC) has been demonstrated to inhibit plant growth and strengthen seedlings. The present study demonstrated that the root growth of Thompson seedless grapevine seedlings was significantly enhanced by the application of CCC treatment. Nevertheless, the precise mechanism by which CCC regulates plant root growth remains to be elucidated. Consequently, an RNA-sequencing (RNA-Seq) analysis was conducted on grapevine roots subjected to CCC treatment and those undergoing natural growth. A total of 819 differentially expressed genes were identified. Subsequently, Gene Ontology (GO) functional enrichment and weighted gene co-expression network analysis (WGCNA) identified the Copper (Cu) homeostasis-associated genes, VvCTr4/5/6/8 and VvFRO4, which play a pivotal role in mediating the effect of CCC. To further elucidate the transcription factor regulating these Cu homeostasis-associated genes, the key transcription factor VvbHLH053 was identified based on the PlantTFDB database, WGCNA results, and expression patterns under CCC treatment. Furthermore, multiple bHLH binding sites were identified on the promoters of VvCTr4/5/6 and VvFRO4. The GUS activity analysis and dual-luciferase assay demonstrated that VvbHLH053 can directly regulate the expression of VvCTr5/6 and VvFRO4. These findings reveal the feedback mechanism of grapevine root growth mediated by CCC and establish a direct functional relationship between CCC, VvbHLH053, and Cu homeostasis-associated genes that regulate root growth. Full article

Chlormequat chloride (CCC), as a commonly used plant growth regulator in the production of rhizomatous medicinal herbs, can effectively control the bolting phenomenon in Angelica sinensis, significantly increasing the yield of underground rhizomes (medicinal part). However, its specific effects on the intrinsic quality of Angelica sinensis, especially medicinal components, require further investigation. The objective of this study is to conduct a thorough examination of CCC residue and its influence on the yield and medicinal components of Angelica sinensis. By spraying different concentrations of CCC on Angelica sinensis, we systematically monitored the final yield of Angelica sinensis Radix (ASR) in each treatment group and the residual concentration of CCC in ASR. Using UPLC-QTOF-MS technology, we conducted an in-depth analysis of the metabolic profile of ASR. Subsequently, UFLC-MS/MS was employed to accurately quantify the changes in the content of nine key active components in ASR. The results of this study indicate that the application of CCC significantly improves the yield of ASR, with the best effect observed at 0.1 g/L, resulting in a yield increase of 24.8%. Meanwhile, the residual amount of CCC in ASR is positively correlated with the application concentration, with the residual levels as high as 7.12 mg/kg in the high-concentration treatment group. Metabolomic analysis preliminarily identified 21 chemical components in ASR, including four organic acids and 13 phthalides. It is worth noting that the quantitative analysis results indicate significant changes in active components such as butylphthalide, Z-ligustilide, and ferulic acid after the application of CCC. Specifically, high-concentration CCC significantly increased the content of butylphthalide and levistolide A, while low-concentration CCC significantly promoted the accumulation of coniferyl ferulate and senkyunolide A, accompanied by a significant decrease in Z-ligustilide and ferulic acidy. In conclusion, while CCC use can increase yield, the associated increase in residues and imbalanced composition ratios may threaten the quality and safety of ASR. Therefore, it is crucial to control the amount of CCC used rationally to balance yield enhancement and quality assurance. Full article

Ferroptosis hallmarked by lipid peroxidation and iron homeostasis imbalance is involved in the occurrence and development of various diseases. The plant growth regulator chlormequat chloride (CCC) can contribute to the causality and exacerbation of reproductive disorders. However, the mechanism by which CCC may cause Leydig cell attenuation remains poorly understood. In this study, TM3 Leydig cells were used to investigate the inhibitory effect of CCC on cell growth and its possible mechanism. The results showed that CCC caused apoptosis, pyroptosis, ferroptosis and necroinflammation in TM3 cells. By comparing the effects of ferroptosis inhibitor Ferrostatin-1 (Fer-1) and pan-Caspase inhibitor Z-VAD-FMK (ZVF) on lipid peroxidation and Caspase-mediated regulated cell death (RCD), we found that Fer-1 was better at rescuing the growth of TM3 cells than ZVF. Although ZVF reduced mitochondrial ROS level and inhibited the activation of Caspase3 and Caspase1, it could not significantly ameliorate lipid peroxidation and the levels of IL-1β and HMGB1 like Fer-1. Therefore, ferroptosis might be a key non apoptotic RCD mode responsible for CCC-driven inflammation, leading to weakened viability and proliferation of TM3 cells. In addition, overexpression of ferritin light chain (FTL) promoted the resistance of TM3 cells to CCC-induced ferroptosis-mediated inflammation and to some extent improved the inhibition of viability and proliferation. Altogether, ferroptosis-initiated inflammation might play a key role in CCC-impaired TM3 cell growth. Full article

Chemical topping involves using plant growth regulators to facilitate the rapid transition of cotton into reproductive growth, similar to manual topping (MT), thereby enhancing cotton yield. Despite its benefits, high-temperature stress following cotton topping often reduces cotton yield. Therefore, developing an effective formula capable of not only inhibiting cotton top growth but also alleviating high-temperature stress is of critical importance. In this study, chlormequat chloride salicylic acid ionic liquids (CSILs) were synthesized via the acid–base neutralization of salicylic acid (SA) and 2-chloro-N,N,N-trimethyl ethanaminium hydroxide, obtained from the reaction between potassium hydroxide and chlormequat chloride (CCC). The resulting CSILs were characterized using various techniques, including nuclear magnetic resonance (NMR), Fourier transformation infrared spectroscopy (FTIR), and ultraviolet-visible light (UV-vis) spectroscopy. The characterization results confirmed the successful synthesis of CSILs as a novel water-soluble cotton-topping agent. Notably, compared with CCC treatment, CSILs at the same concentration exhibited a more sustainable and stable inhibition effect on cotton tip growth, resulting in an 11% increase in cotton yield. These findings suggest that CSILs have a greater potential for use in cotton chemical topping compared with CCC. Furthermore, compared with MT, the MDA content of cotton leaves treated with CSILs was reduced, and the activities of POD and SOD were increased under high-temperature stress. Moreover, these effects became more pronounced with an increasing CSIL concentration, highlighting the positive impact of CSILs in alleviating high-temperature stress on cotton. Notably, no significant difference in cotton yield was observed between the CSIL treatment at 120 g AI ha⁻¹ and the MT treatment. Thus, this study underscores the significant potential of CSILs in both cotton topping and enhancing resistance to high-temperature stress. Full article

Wheat is the cereal most susceptible to lodging, particularly during the flowering period and at the early ripening stage. The use of plant growth retardants (PGRs) is especially recommended when intensive nitrogen (N) fertilisation is applied, which increases the susceptibility of plants to lodging. This paper presents the results of tests into the effects of PGRs (PGR0—control; PGR1—chlormequat chloride (CCC) + trinexapac-ethyl (TE); PGR2—chlormequat chloride (CCC) + ethephon (ET)), and N dose—N0, N20, N40, and N60 [0, 20, 40, and 60 kg N ha⁻¹] on the content of selected plant secondary metabolites (PSM) in the Indian dwarf wheat (Triticum sphaerococcum Percival) of the Trispa cultivar, and on the abundance of insect pests. In the developmental stage of wheat (BBCH 39), insects were collected with an entomological net. The study also investigated the effect of experimental factors on the physicobiochemical properties of the soil (pH in KC, granulometric composition, total organic carbon TOC, total nitrogen TN, fractional composition of humus, and the activity of enzymes). An increase in the plant secondary metabolite (PSM) and FRAP (ferring reducing ability of plasma) contents following the application of PGRs and N fertilisation already from as low a rate as 20 kg ha⁻¹ was demonstrated. A significant positive correlation was noted between the abundance of Oulema spp. and the contents of total polyphenols, chlorogenic acid, and FRAP. No such relationship was noted for Aphididae or Thysanoptera. TOC content was higher on the plots on which N fertilisation was applied at the highest rate and after the application of PGRs. The factor determining the TN content was N fertilisation. Soil samples of the PGR0 N0 treatment were characterised by the greatest proportion of carbon in the humic and fulvic acid fractions and by the smallest proportion of carbon in the humin fraction. N fertilisation increased the proportion of carbon in the humin fraction on the plots on which no PGRs were applied. The study demonstrated an increase in the activity of oxidoreductive enzymes following the application of higher N rates. The application of PGRs resulted in no inhibition of enzymes in the soil compared to the control (PGRs0). Full article

Rapid growth and scattered plant types are urgent issues for potted Melaleuca alternifolia. An effective strategy for dwarfing cultivation is the exogenous application of plant growth regulators (PGRs) to plants. However, for many non-wood forest species, there is currently limited understanding of the regulatory mechanism of dwarfing effects of PGRs, which greatly limits the application of PGRs. In this study, three PGRs, paclobutrazol (PP333), uniconazole (S3307), and chlormequat chloride (CCC) were applied to dwarf terpinen-4-ol M. alternifolia. By observing the morphological characteristics and leaf anatomy of M. alternifolia after dwarfing and measuring its photosynthetic characteristics and physiological and biochemical indexes, the dwarfing effect of the three PGRs and the underlying mechanisms were investigated to provide a reference for the cultivation of M. alternifolia by dwarfing. The results show that the PP333 (P3) treatment at 2000 mg·L⁻¹ had the best dwarfing effect on M. alternifolia, with a compact plant shape, thicker stems, and green leaf color. At the same time, it increased the chlorophyll contents, changed the blade structure, increased the content of soluble substances and the activity of antioxidant enzymes, increased the endogenous hormones indole-3-acetic acid (IAA), gibberellin A3 (GA3), and trans-zeatin-riboside (ZR), and decreased abscisic acid (ABA) levels. Full article

The effects of four plant growth regulators on Crocus sativus L. (saffron) yield and performance were studied in two consecutive years under field conditions. Saffron corms were immersed in solutions of gibberellic acid (GA₃), salicylic acid (SA), paclobutrazol (PBZ), chlormequat chloride (CCC), distilled water (hydroprime), and dry corms as the control. Results showed that among the different treatments, plants primed with GA₃ 500 μM had the highest flower fresh weight and stigma dry weight. In contrast, primed corms with 1000 μM CCC and 100 μM PBZ had the lowest flower dry weight. Furthermore, the plants primed with SA 1400 had the highest leaf numbers, leaf dry weight, and leaf area index (LAI). Plants treated with GA₃ induced narrow but the longest leaves, while those treated with SA showed the widest ones. It was also demonstrated that the application of CCC and PBZ can produce shorter leaves. Furthermore, the greatest numbers of daughter corms were obtained in 1400 μM SA. Both PBZ and CCC were reported to have no impacts on the corm numbers but produced larger and heavier daughter corms. The results revealed that the priming of saffron corms with GA₃ and then SA improved saffron growth and yield. Full article

Shipping of in vitro micro-cuttings in tubes or jars is a frequently used method as the plants are more likely to quickly reproduce and comply with quarantine regulations in plant germplasm distribution. However, these containers are fragile during transportation. To diminish the risk associated with the long-distance shipping of in vitro plants, a safe and widely applicable packing and conservation technique based on microplate and slow growth was developed in this study. Potato cultivar ZHB and ginger cultivar G-2 were used to optimize the system with microplates (96 wells), vacuum-sealed packaging, and slow-growth techniques. Under regular culture conditions, packing in vacuum-sealed microplates reduced the survival of ZHB and G-2 micro-cuttings to 85.8% and 20.0%, respectively, and regeneration to 61.8% and 0%, respectively. Reducing the temperature to 10 °C maintained the survival of ZHB and G-2 micro-cuttings in the range of 83.3–100% after 60 days. Exposure to darkness decreased the survival of G-2 and inhibited regrowth. Thus, conservation in darkness at 10 °C is suggested. The effects of iron concentration and plant growth retardants were further assessed. The addition of 1/4 MS medium combined with 100 mg/L chlormequat chloride (CCC) resulted in full survival and growth inhibition of plantlets, without malformation identified. Finally, incubation with 1/4 MS medium supplemented with 100 mg/L CCC in vacuum-sealed microplates at 10 °C in the dark resulted in high survival and suppressed germination. Sweet potato HXS was incubated as well to test the broad-spectrum applications of the technique; 100% survival and 6.7% germination was gained. Morphological indices of released cuttings recovered to control levels after two cycles of subculture in MS medium. A 0.1–0.2% genetic variation was detected by SSR and ISSR, suggesting genetic stability of the conserved samples. Finally, micro-cuttings were safely transported to cities located thousands of kilometers away without package and sample damage. Our results enable easy distribution of in vitro plant germplasms. Full article

Plant growth regulators (PGRs) are used as a management tool to minimize plant height and subsequent stem lodging in grass seed crops. Their efficacy is influenced not only by the method of application, but also by the management and genetic variations within and between species. This aim of the study was to evaluate the effect of PGRs on morphological traits of generative tillers and seed yield of Festuca rubra L ssp. rubra (strong creeping red fescue) and F. r. L ssp. commutata (Chewings red fescue) under low and medium doses of spring nitrogen fertilization (40 and 70 kg N ha⁻¹). PGRs were applied as: chlormequat chloride (CCC) at BBCH 30–31; CCC at BBCH 30–31 + ethephon (ET) at BBCH 37–39; CCC at BBCH 30–31 + trinexapac-ethyl (TE) at BBCH 37–39. All the application methods of PGRs resulted in the shortening of the second internode, and the sequential application of CCC with ET or TE also resulted in the shortening of the third internode. In each PGR treatment, the lodging index in the plant (canopy height to tiller length ratio) was higher than that of the control. PGRs had a beneficial effect on the seed yield. The greatest increase in the seed yield was recorded after the application of CCC+TE. No interaction between PGRs and spring N fertilization rates on the seed yield of red fescue. The increase in the dose of spring nitrogen fertilizer from 40 to 70 kg N ha⁻¹ resulted in a significant increase in yield. Seed yield of chewing red fescue cv. Dorosa was 29% higher than strong creeping red fescue cv. Nista, mainly due to an increase in the number of generative tillers. Full article

Seedling overgrowth always develops in undernourished plants due to biotic or abiotic stresses, which significantly decrease the yield of crops and vegetables. It is known that the plant growth retardants paclobutrazol (PBZ) and chlormequat chloride (CCC) are the most commonly used chemicals in controlling seedling height in plants by regulating the gibberellin (GA) biosynthesis pathway. However, the exact molecular regulation mechanism remains largely unknown. This study performed a comprehensive transcriptome profile to identify significantly differentially expressed genes after adding CCC and PBZ to the water culture seedling raising system for the first time. According to the obviously restrained shoots and roots, the GA biosynthesis genes were significantly decreased, as well as the endogenous GA content being reduced. Intriguingly, the GA signaling pathway genes were affected in opposite ways, increasing in roots but decreasing in shoots, especially regarding the phytochrome interacting factor SlPIF1 and the downstream genes expansins (SlEXPs), which promote cell wall remodeling. Further study found that the most down-regulated genes SlEXPA5 and SlEXPA15 were expressed specifically in shoot tissue, performing the function of repressing elongation, while the up-regulated genes SlEXPB2 and SlEXPB8 were proven to be root-specific expressed genes, which may promote horizontal elongation in roots. This research reported the comprehensive transcriptome profiling of plant growth retardants in controlling seedling overgrowth and restraining GA biosynthesis through the regulation of the GA signaling-related genes SlPIF1 and SlEXPs, with an opposite expression pattern between roots and shoots. Full article

Vegetative propagation using runner plants is an important method to expand the cultivation area for the strawberry (Fragaria × ananassa Duch.). However, excessively long runners need an increased total amount of nutrients and energy to receive elongation from mother plants, which may lead to poor growth or reduced output. The use of plant growth regulators (PGRs) is an adoptable way to solve such problems. The objectives of this experiment were to study the effects of PGRs and their application methods on the growth and development of runners, runner plants, and mother plants, and also to find effective ways to control the number and length of runners without harmful side effects. Chlormequat chloride (CCC), 6-benzylaminopurine (BA), and ethephon (ETH) at a concentration of 100 mg·L⁻¹ were applied via three different methods: injection into crowns, medium drench, and foliar spray. The results showed that BA injection into crowns was the most effective combination among all treatments, which prominently shortened the length of runners and increased the number of runners and leaves on a single plant. Furthermore, plants with BA solution injection tended to produce stronger runners with higher fresh and dry weights, without affecting the health states of mother plants. The ETH solution seemed to have toxic effects on plants, by leading many dead leaves and weak runners, and increased activities of antioxidant enzymes. Other than the injection method, the other two application methods of the CCC solution did not significantly affect the growth and development of both cultivars. Runner plants grown for 30 days were not affected by any treatments, and they were in similar conditions. Overall, BA injection into crowns is recommended for controlling the number and length of strawberry runners. Full article