Stem Growth Research Articles

Extraction and characterization of novel alternative cellulosic fiber for sustainable textiles from Aloe barbadensis Miller stems (agricultural waste)

Novel research has been conducted on Aloe vera, focusing on stems fiber (agricultural waste), for the extraction of cellulosic fiber, an area lacking prior scientific exploration. This fiber is being reported for the first time in the scientific community. Aloe barbadensis Miller variety was subjected to various cultivation methods, including the application of inorganic and organic fertilizers, along with the removal of lower leaves to promote stem growth. Stem fibers were extracted using the water retting method and subsequently analyzed. The moisture content was 55.35 % and 6.99 % ash content in the fibers. The bacteriostatic analysis of Aloe vera fibers was assessed against four bacterial strains, with both ethanol and water extracts showing varying degrees of inhibition zones. The UV–Visible spectrum exhibited a distinct λmax at 247 nm in ethanol, while FT-IR analysis provided characteristic peaks at 3759, 1590, 1750, 1663, 1250, 564, SEM images displayed the smooth surface morphology of the fibers, and X-ray diffraction analysis indicated a high degree of crystallinity (78.67 %), suggesting a well-structured and crystalline nature. Energy dispersive X-ray (EDX) analysis was conducted to determine the elemental composition of the fibers, revealing the presence of carbon, oxygen, calcium, and copper, with carbon being the predominant element in cellulose. These results showed promising properties suggesting potential applications in textile industry as an alternative sustainable natural cellulosic fiber.

Populus trichocarpa EXPA6 Facilitates Radial and Longitudinal Transport of Na+ under Salt Stress.

Expansins are cell wall (CW) proteins that mediate the CW loosening and regulate salt tolerance in a positive or negative way. However, the role of Populus trichocarpa expansin A6 (PtEXPA6) in salt tolerance and the relevance to cell wall loosening is still unclear in poplars. PtEXPA6 gene was transferred into the hybrid species, Populus alba × P. tremula var. glandulosa (84K) and Populus tremula × P. alba INRA '717-1B4' (717-1B4). Under salt stress, the stem growth, gas exchange, chlorophyll fluorescence, activity and transcription of antioxidant enzymes, Na+ content, and Na+ flux of root xylem and petiole vascular bundle were investigated in wild-type and transgenic poplars. The correlation analysis and principal component analysis (PCA) were used to analyze the correlations among the characteristics and principal components. Our results show that the transcription of PtEXPA6 was downregulated upon a prolonged duration of salt stress (48 h) after a transient increase induced by NaCl (100 mM). The PtEXPA6-transgenic poplars of 84K and 717-1B4 showed a greater reduction (42-65%) in stem height and diameter growth after 15 days of NaCl treatment compared with wild-type (WT) poplars (11-41%). The Na+ accumulation in roots, stems, and leaves was 14-83% higher in the transgenic lines than in the WT. The Na+ buildup in the transgenic poplars affects photosynthesis; the activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT); and the transcription of PODa2, SOD [Cu-Zn], and CAT1. Transient flux kinetics showed that the Na+ efflux of root xylem and leaf petiole vascular bundle were 1.9-3.5-fold greater in the PtEXPA6-transgenic poplars than in the WT poplars. PtEXPA6 overexpression increased root contractility and extensibility by 33% and 32%, indicating that PtEXPA6 increased the CW loosening in the transgenic poplars of 84K and 717-1B4. Noteworthily, the PtEXPA6-promoted CW loosening was shown to facilitate Na+ efflux of root xylem and petiole vascular bundle in the transgenic poplars. We conclude that the overexpression of PtEXPA6 leads to CW loosening that facilitates the radial translocation of Na+ into the root xylem and the subsequent Na+ translocation from roots to leaves, resulting in an excessive Na+ accumulation and consequently, reducing salt tolerance in transgenic poplars. Therefore, the downregulation of PtEXPA6 in NaCl-treated Populus trichocarpa favors the maintenance of ionic and reactive oxygen species (ROS) homeostasis under long-term salt stress.

Antagonistic interactions between cytokinin and gibberellin during initial stem growth and leaf structure of royal poinciana [Delonix regia (Bojer ex. Hook.) Raf.

Antagonistic interactions between cytokinin and gibberellin during initial stem growth and leaf structure of royal poinciana [Delonix regia (Bojer ex. Hook.) Raf.

Environmentally friendly slow-release urea fertilizer based on modified chitosan membrane

The inefficient use of conventional fertilizers has prompted the exploration of slow-release fertilizer (SRF) systems to enhance plant nutrient delivery and uptake. This study investigates the potential of the chitosan (CS) membrane modified with succinic acid (SA) and calcium ions (Ca2+) as an effective SRF system. The CS/SA-U/Ca-coated membrane can extend the release period of urea, thereby optimizing fertilizer efficiency and promoting plant growth. The structural and chemical features of the CS/SA-U/Ca membrane were comprehensively analyzed. The modification with Ca2+ increased the membrane’s thickness, decreased its swelling degree, and resulted in a rougher, more porous surface, all of which contributed to a more controlled release of urea. Urea release profiles were evaluated in both water and soil, demonstrating that the CS/SA-U/Ca coating extended the release period to 20 days in water and over 30 days in soil. Quantitative UV–Vis spectrophotometry and qualitative assessments were used to measure the urea release and evaluate the impact of the SRF on vegetable plant growth. Experimental results demonstrated a significant enhancement in plant growth, with a 46 % increase in stem growth and a doubling of leaf count compared to control plants without the SRF membrane. These findings suggest that the CS/SA-U/Ca-coated SRF system holds promise for optimizing fertilizer use and promoting plant growth by providing a more controlled nutrient release.

Auxin-Producing Bacteria Used as Microbial Biostimulants Improve the Growth of Tomato (Solanum lycopersicum L.) Seedlings in Hydroponic Systems.

Seven auxin-producing endophytic bacterial strains (Azospirillum spp., Methylobacterium symbioticum, Bacillus spp.), and two different combinations of these strains were used to verify their influence on tomato during germination and development in hydroponic conditions where, as a novelty for Canestrino di Lucca cultivar, endophytic bacteria were inoculated. To emphasize the presence of bacterial auxins in roots and stems of seedlings, both in situ staining qualitative assessment and quantitative analysis were carried out. Moreover, hypogeal and epigeal growth of the plantlets were measured, and correlation analyses were conducted to examine the relationship between the amount of indolacetic acid (IAA) produced by the bacterial strains and root and stem parameters. Plantlets treated with microbial inoculants showed a significant increase in the survival rate compared to the control treatment. The best results as IAA producers were from Azospirillum baldaniorum Sp245 and A. brasilense Cd, which also induced significant root growth. On the other hand, Bacillus amyloliquefaciens and B. licheniformis induced the best rates in stem growth. These findings highlight the potential for using endophytic bacterial strains in a hydroponic co-cultivation system that enables inoculating plantlets, at an early stage of growth (5 days old).

Intrapericardial Administration to Achieve Localized and Targeted Treatment for Cardiac Disease.

Intrapericardial administration has been proposed as an alternative delivery route of pharmacological agents via the bilaminar sac of pericardium surrounding the heart. To date, intrapericardial administration has entailed the localized administration of a broad spectrum of therapeutic agents. These agents include stem cells, extracellular matrix, growth factor, drugs, bioactive materials, and genetic materials, to the heart and coronary arteries. The route not only overcomes the limitations associated with traditional systemic administration methods, but also presents multiple intrinsic advantages over the other approaches, allowing greater therapeutic actions. Intrapericardial administration exhibits versatility in addressing certain cardiac conditions and ongoing research in this field certainly holds promise for further innovations and advancements to improve cardiac treatment. Thus, this review discusses the anatomy and physiology of the pericardium, the intrapericardial administration access routes, the recent application of intrapericardial delivery in the context of cardiac repair as well as the challenges associated with the approach.

A florigen-expressing subpopulation of companion cells expresses other small proteins and reveals a nitrogen-sensitive FT repressor.

The precise onset of flowering is crucial to ensure successful plant reproduction. The gene FLOWERING LOCUS T (FT) encodes florigen, a mobile signal produced in leaves that initiates flowering at the shoot apical meristem. In response to seasonal changes, FT is induced in phloem companion cells located in distal leaf regions. Thus far, a detailed molecular characterization of the FT-expressing cells has been lacking. Here, we used bulk nuclei RNA-seq and single nuclei RNA (snRNA)-seq to investigate gene expression in FT-expressing cells and other phloem companion cells. Our bulk nuclei RNA-seq demonstrated that FT-expressing cells in cotyledons and in true leaves differed transcriptionally. Within the true leaves, our snRNA-seq analysis revealed that companion cells with high FT expression form a unique cluster in which many genes involved in ATP biosynthesis are highly upregulated. The cluster also expresses other genes encoding small proteins, including the flowering and stem growth inducer FPF1-LIKE PROTEIN 1 (FLP1) and the anti-florigen BROTHER OF FT AND TFL1 (BFT). In addition, we found that the promoters of FT and the genes co-expressed with FT in the cluster were enriched for the consensus binding motifs of NITRATE-INDUCIBLE GARP-TYPE TRANSCRIPTIONAL REPRESSOR 1 (NIGT1). Overexpression of the paralogous NIGT1.2 and NIGT1.4 repressed FT expression and significantly delayed flowering under nitrogen-rich conditions, consistent with NIGT1s acting as nitrogen-dependent FT repressors. Taken together, our results demonstrate that major FT-expressing cells show a distinct expression profile that suggests that these cells may produce multiple systemic signals to regulate plant growth and development.

Hitting two birds with one stone: A ce-modified Fe-based bi-functional material reinforced fenton-like system for complete removal of organophosphorus pesticides

Organophosphorus pesticides, widespread and hazardous to ecosystems and human health, were mainly decomposed thoroughly by advanced oxidation processes (AOPs). However, the generated inorganic phosphate (IP) was prone to accumulation and led to eutrophication of water bodies. Herein, a Fe/Ce bimetallic-loaded biochar (FeCe@BC-400–5) with excellent H2O2 activation and IP adsorption properties was designed and used to treat glyphosate (GLY)-contaminated water. Results showed that ∼ 92 % of GLY (20 mg P/L) was removed in the FeCe@BC-400–5/H2O2 system within 120 min, and the converted IP was almost completely adsorbed onto FeCe@BC-400. Experiment and theoretical calculations revealed that Ce doping facilitated the capture of H2O2 by the iron-based catalysts and promoted the activation of H2O2 to produce more reactive oxygen species (•OH and O2•-). Meanwhile, the released IP was adsorbed onto FeCe@BC-400–5 via inner-sphere complexation to avoid secondary contamination. Intriguingly, toxicity tests showed that the degraded GLY solution in FeCe@BC-400–5/H2O2 system promoted germination rate, root and stem growth of Solanum nigrum L (herbaceous plant). This study provided a new idea on constructing oxidation-adsorption bifunctional materials for the comprehensive removal of organophosphorus in the Fenton-like field.

Assessment of pilot-scale sewage sludge pelletization for non-food crop fertilization: nutrient content, pathogenicity, and growth performance.

Application of sewage sludge as fertilizer can be beneficial for sustainable agriculture as it could largely account for nitrogen and phosphorus demand for crops and has lower costs compared to other disposal routes, e.g., incineration, and sanitary landfills. This study evaluates the feasibility of pilot-scale pelletization of sewage sludge for non-food crops (e.g., ornamental plants). The co-pelletization method was designed by mixing sewage sludge and binder (tapioca starch) at a 9:1 sludge-to-starch weight ratio. The amount of nitrogen (N), phosphorus (P), and potassium (K) of the resultant pellets were determined at 5.7%, 4.9%, and 0.2%, respectively. Following Malaysian and US Standards, non-essential elements and pathogenicity of the pelletized sewage sludge were measured below the predetermined limits and hence safe for agricultural application. The planting trial using 50% inorganic fertilizer + 50% sewage sludge pellets exhibited a promising result on the growth of the flowering plant Celosia plumosa, with having better dimension and color, 20% higher in height, 4% more chlorophyll content, 54% more leaf, 43% greater stem growth, and 27% more flowers compared to control. Likewise, the planting trial on Tagetes erecta resulted in 10.5% wider leaf, 10.6% heavier leaf dry weight, and 12.5% more chlorophyll content compared to control with full usage of inorganic fertilizer. By considering liquidities to operate the production facility, the economic analysis estimated that the production cost per ton of pelletized sewage sludge produced was USD 0.98.

Sensitivity of sub-annual grey pine (Pinus sabiniana) stem growth to water supply and demand in central California

Pinus sabiniana (grey pine) is a common associate of Quercus douglasii (blue oak) in the iconic, ecologically-rich, and economically-relevant Mediterranean woodland savannah of California, USA. While there are dozens of Q. douglasii sites in the International Tree-Ring Data Bank, P. sabiniana was conspicuously absent, and little is known about its growth patterns or water relations. Here, we introduce a new tree-ring chronology of P. sabiniana collected in central California and assess climatic drivers of annual and sub-annual growth. Specifically, we examine earlywood, latewood, and total annual ring widths and analyse their relationships with variables related to water supply (precipitation, soil moisture) and water demand (air temperature, potential evaporation rate). Annual and earlywood widths had nearly identical responses to climate, likely because annual widths mostly consisted of earlywood (mean: 88 %). In both cases, growth was strongly and positively associated with water supply and negatively associated with water demand. Soil moisture was, by far, the strongest and most temporally-consistent correlate of P. sabiniana growth: correlations between soil moisture and annual growth were >0.8 for five contiguous 3-month seasons. Other variables were significant, in part, because of their influence on soil moisture. The association between latewood growth and climate was qualitatively similar but weaker and, with the exception of soil moisture, more seasonally localised (precipitation was relevant in winter and early spring and water demand variables were relevant in summer, somewhat later in the season than for total ring width and earlywood). Further, P. sabiniana growth was nearly always more sensitive to soil moisture than growth of either co-located Q. douglasii or P. ponderosa (ponderosa pine) at a neighbouring site, suggesting that it may act as a particularly sensitive harbinger of drought stress in this ecosystem.

Methionine Synthase 2 Represses Stem Cell Maintenance of Arabidopsis thaliana in Response to Salt Stress.

Salt stress represses the growth and development of plants that mainly depend on the continual propagation and differentiation of stem cells. WUSCHEL (WUS)/WUSCHEL-RELATED HOMEOBOX (WOX) family proteins determine stem cell fate in plants under ever-changing environments. It is not yet known how plant stem cell homeostasis is regulated under salt stress. Methionine synthase catalyzes the formation of methionine by methylating homocysteine in the one-carbon metabolism pathway. In this work, we investigated the role of Arabidopsis METHIONINE SYNTHASE 2 (AtMS2) in stem cell homeostasis under salt stress. The results showed that AtMS2 represses the stem cell maintenance of Arabidopsis in response to salt stress. Under normal growth conditions, AtMS2 is mainly localized in the cytoplasm. However, under salt stress, it exhibits significant accumulation in the nucleus. AtMS2 interacts with the WUS/WOX protein, and, together, they repress WUS/WOX expression by binding to its promoter. The mutation in AtMS2 resulted in enhanced salt tolerance. Therefore, AtMS2 might act as a key negative regulator to repress the stem cell maintenance and growth of Arabidopsis under salt stress.

Soil drought sets site specific limits to stem radial growth and sap flow of Douglas-fir across Germany.

Soil drought during summer in Central Europe has become more frequent and severe over the last decades. European forests are suffering increasing damage, particularly Norway spruce. Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco), a non-native tree species, is considered as a promising alternative to build drought-resilient forests. The main goal of this study was to investigate the intraannual radial stem growth and sap flow performance of Douglas-fir along a precipitation gradient across Germany under severe drought. Sap flow and stem radial changes of up to ten trees each at four sites with different precipitation regimes were measured in combination with volumetric soil water content during the growing season of 2022. Measurements of stem radial changes were used to calculate the trees' stem water deficit, a proxy for tree water status and drought stress. The severe summer drought of 2022 led to an early growth cessation and a significant reduction in daily sap flow at all four sites monitored. We could identify a site-specific threshold in soil water availability ranging between 21.7 and 29.6% of relative extractable water (REW) under which stem water reserves cannot be replenished and thereby inhibiting radial growth. We could also demonstrate that at this threshold, sap flow is heavily reduced to between 43.5 and 53.3%, and for a REW below 50%, sap flow linearly decreases by 1.1-2.0% per 1% reduction in REW. This reduction tends to follow the humidity gradient, being more pronounced at the most oceanic characterized site and suggesting an adaptation to site conditions. Even though Douglas-fir is considered to be more drought stress resistant than Norway spruce, growth and sap flow are greatly reduced by severe summer drought, which became more frequent in recent years and their frequency and intensity is likely to increase. Our results suggest that timber production of Douglas-fir in Central Europe will decline considerably under projected climate change, and thus pointing to site specific growth constraints for a so far promising non-native tree species in Europe.

The Influence of Logging-Related Soil Disturbance on Pioneer Tree Regeneration in Mixed Temperate Forests.

The recovery of soil properties and the proper growth of natural tree regeneration are key elements for maintaining forest productivity after selective logging operations. This study was conducted on the soil properties and natural growth of two pioneer seedling species of alder and maple which were on skid trails in the mixed beech forests of northern Iran. To examine the long-term effects, we randomly selected six skid trails, with two replicates established for each of three time periods since last use (10, 20, and 30 years ago). Random plots 4 m × 10 m in size, three plots on each skid trail and six plots on areas without soil compaction (control), were selected. Measurements included the physical and chemical properties of the soil and the growth, and the architectural and qualitative characteristics of the seedlings. The results showed that all the soil properties of the 10- and 20-year-old skid trails were significantly different from the control area (except for the soil moisture in the 20-year-old skid trail). The 30-year-old skid trail showed values of other soil properties which were not significantly different from the control area, except for the amounts of organic matter and soil nitrogen, which was less than the control. The skid trails had a negative effect on all of the growth, qualitative, and architectural indices of seedlings. The characteristics of seedlings were related to soil characteristics and had the highest correlation with the soil penetration resistance (R-value from -0.41 to -0.63 for stem growth, p < 0.05; -0.57 to -0.90 for root growth, p < 0.01; and -0.76 to -0.86 for biomass, p < 0.01). The correlation coefficient between soil penetration resistance and the Dickson quality index of alder and maple seedlings was, respectively, -0.74 and -0.72, p < 0.01. The negative effect of soil compaction on root growth (-27.69% for alder seedlings and -28.08% for maple seedlings) was greater than on stem growth (-24.11% for alder seedlings and -16.27% for maple seedlings). The amount of growth, qualitative, and architectural indices of alder seedlings were higher than that of maple seedlings. Although alder is a better choice as compared to maple seedling in the initial year, the results of our study show that it is recommended to plant both alder and maple on skid trails after logging operations.

Effect of IBA and growing media on growth and survival of stem cutting in Kagzi Lime (Citrus aurantifolia)

Effect of IBA and growing media on growth and survival of stem cutting in Kagzi Lime (Citrus aurantifolia)

Effect of Cellular Dosage of Bone Marrow Aspiration Concentrate on the Radiological Outcomes in Knee Osteoarthritis: A Phase I Dose-Escalation Study.

Knee osteoarthritis(KOA), a chronic degenerative disease, significantly impairs quality of life due to pain and mobility limitations. Traditional treatments focus on symptom management without addressing the underlying disease progression, leading to a growing interest in regenerative medicine approaches. Bone marrow aspirate concentrate (BMAC), rich in mesenchymal stem cells and growth factors, has shown potential for cartilage repair and symptom relief in KOA. Despite promising outcomes, the optimal BMAC dosage for knee OA treatment remains undetermined. This study aims to evaluate the radiological outcomes of varying BMAC dosages in knee OA treatment. This prospective controlled dose-escalation study involved 75 patients with early-stage knee OA, categorized into three groups based on BMAC dosage administered 10x106 cells (low-dose group), 50×106 cells (medium-dose group), or 100x106 cells (high-dose group). All the patients underwent a single intra-articular injection of BMAC and were monitored over a year. The primary outcomes include magnetic resonance observation of cartilage repair tissue (MOCART 2.0) score to assess the cartilage. We noted significant improvement in the overall MOCART score (p=0.027) and subchondral change sub-score (p=0.048) and defect filling sub-score (p=0.025) in the medium- and high-dose cohorts compared to the low-dose cohort at 1year follow-up. Although we noted positive correlation between the clinical and radiological outcome (r=0.43), we did not find any significant different in the clinical outcome between the treatment groups. BMAC for OA knee resulted in significant improvement in the radiological scores compared to the baseline. Medium and high doses of BMAC result in significantly higher radiological scores compared to low-dose BMAC at 1year. However, the radiological improvement did not translate into functional improvement, irrespective of the dosage administered at 1year. Further research is necessary on the long-term outcomes to understand and optimize the dosing strategy based on clinico-radiological results.

Toxicological response and bioaccumulation of strontium in Triticum durum (Nachit) and Triticum aestivum (Ibtissam)

The present study examines the toxicological effects and bioaccumulation of strontium (Sr2+) in two Moroccan wheat species, Triticum durum (Nachit) and Triticum aestivum (Ibtissam). Germination rates and seedling growth parameters were evaluated under Sr2+ concentrations of 0, 10, 100, and 1000 mM. Results revealed a significant decline in germination rates as Sr2+ concentrations increased, with T. aestivum showing higher sensitivity compared to T. durum. Low Sr2+ concentrations (10 mM) initially promoted stem growth in T. aestivum, but growth declined sharply at higher concentrations. Both species sustained growth at moderate Sr2+ concentrations (100 mM), but experienced a substantial reduction at 1000 mM, with T. durum demonstrating slightly better tolerance. Elevated Sr2+ concentrations notably affected root length and stem branching, indicating severe phytotoxic effects. Enzyme activity assays showed that at low Sr2+ concentration (10 mM), GST, CAT, POD, and SOD activities were similar to the control. At moderate concentrations (100 mM), GST and POD activities increased, suggesting enhanced detoxification. At high concentrations (1000 mM), all enzyme activities were significantly elevated, reflecting a robust antioxidative defense mechanism. This study provides valuable insights into the toxicological impacts and physiological responses of these wheat species to Sr2+ stress.

Transcriptomic analysis for the gamma-ray-induced sweetpotato mutants with altered stem growth pattern.

Sweetpotato faces breeding challenges due to physiological and genomic issues. Gamma radiation is a novel approach for inducing genetic variation in crops. We analyzed the transcriptomic changes in gamma ray-induced sweetpotato mutants with altered stem development compared with those in the wild-type 'Tongchaeru' cultivar. RNA sequencing analyses were performed to identify changes in the expression of genes related to stem development. Transcriptomic analysis identified 8,931 upregulated and 6,901 downregulated genes, including the upregulation of the auxin-responsive SMALL AUXIN UP RNA (SAUR) and three PHYTOCHROME INTERACTING FACTOR 4 (PIF4) genes. PIF4 is crucial for regulating the expression of early auxin-responsive SAUR genes and stem growth in Arabidopsis thaliana. In the mutant, several genes related to stem elongation, including PIF4 and those involved in various signaling pathways such as auxin and gibberellin, were upregulated. Our results suggest that gamma ray-induced mutations influence auxin-dependent stem development by modulating a complex regulatory network involving the expression of PIF4 and SAUR genes, and other signaling pathways such as gibberellin and ethylene signaling genes. This study enhances our understanding of the regulatory mechanisms underlying stem growth in sweetpotato, providing valuable insights for genomics-assisted breeding efforts.

Optimal Planting Time for Summer Tomatoes (Lycopersicon esculentum Mill.) Cropping in Korea: Growth, Yield, and Photosynthetic Efficiency in a Semi-Closed Greenhouse.

In Korea, greenhouses are traditionally used for crop cultivation in the winter. However, due to diverse consumer demands, climate change, and advancements in agricultural technology, more farms are aiming for year-round production. Nonetheless, summer cropping poses challenges such as high temperatures, humidity from the monsoon season, and low light conditions, which make it difficult to grow crops. Therefore, this study aimed to determine the best planting time for summer tomato cultivation in a Korean semi-closed greenhouse that can be both air-conditioned and heated. The experiment was conducted in the Advanced Digital Greenhouse, built by the National Institute of Agricultural Sciences. The tomato seedlings were planted in April, May, and June 2022. Growth parameters such as stem diameter, flowering position, stem growth rate, and leaf shape index were measured, and harvesting was carried out once or twice weekly per treatment from 65 days to 265 days after planting. The light use efficiency and yield per unit area at each planting time was measured. Tomatoes planted in April showed a maximum of 42.9% higher light use efficiency for fruit production and a maximum of 33.3% higher yield. Furthermore, the growth form of the crops was closest to the reproductive growth type. Therefore, among April, May, and June, April is considered the most suitable planting time for summer cultivation, which is expected to contribute to reducing labor costs due to decreased workload and increasing farm income through increased yields. Future research should explore optimizing greenhouse microclimates and developing crop varieties tailored for summer cultivation to further enhance productivity and sustainability in year-round agricultural practices.

Physiological and growth responses of Lycium barbarum seedlings to water and salt stresses

Rational exploitation and utilization of brackish water resources is the basis of sustainable agricultural development in the oasis regions of arid inland basin. As a drought-and-salt-tolerant economic crop, irrigation management at seedling stage is particularly important for the fruit yield in Lycium barbarum adulthood. The effects of three irrigation levels (the lower limits of irrigation were 80 % (full irrigation), 70 %, and 60 % of field capacity) and two salinity levels in irrigation water (1.7 (fresh water) and 5.0 dS/m) on physiology and growth of Lycium barbarum seedlings were studied through pot experiments. The results showed that water deficit treatment promoted aboveground plant growth and water use efficiency, but decreased transpiration rate of Lycium barbarum seedlings. Compared with full irrigation, the averaged leaf chlorophyll content (SPAD), base stem diameter, branch diameter, and water use efficiency of Lycium barbarum seedlings under deficit irrigation treatments were increased by 4.6 % – 6.6 %, 15.1 % – 55.5 %, 12.8 % – 41.0 %, and 22.3 % – 23.9 %, respectively, while the transpiration rate was decreased by 6.5 % – 16.1 %. Soil water content under brackish water irrigation was generally slightly higher than that under freshwater irrigation, but its soil salinity was about 5.0 times higher than that under freshwater irrigation. Compared with freshwater irrigation, brackish water irrigation decreased root biomass by 6.7 % – 9.0 % and transpiration rate by 2.5 % – 10.5 %, and increased water use efficiency by 1.9 % – 24.8 %, and meanwhile it also promoted the growth of base stem (11.4 % – 32.4 %), branch (6.4 % – 18.9 %) and leaf aera (2.2 % – 6.8 %). The lower limit of irrigation and the salinity in irrigation water imposed significant interactive effects on photosynthesis, stem and branch growth, and crop water consumption of Lycium barbarum seedlings. The analysis results of structural equation model showed that the lower limit of irrigation mainly affected water use efficiency of Lycium barbarum seedlings, while the salinity in irrigation water mainly did its root biomass. The lower limit of irrigation with 70 % field capacity may be a preferred scheme of brackish water irrigation for the planting of Lycium barbarum seedlings in arid oasis regions.

The REPLUMLESS Transcription Factor Controls the Expression of the RECEPTOR-LIKE CYTOPLASMIC KINASE VI_A2 Gene Involved in Shoot and Fruit Patterning of Arabidopsis thaliana.

The promoter of the RECEPTOR-LIKE CYTOPLASMIC KINASE VI_A2 (RLCK VI_A2) gene contains nine binding sites for the REPLUMLESS (RPL) transcription factor. In agreement, the expression of the kinase gene was strongly downregulated in the rpl-4 mutant. Comparing phenotypes of loss-of-function mutants, it was revealed that both genes are involved in stem growth, phyllotaxis, organization of the vascular tissues, and the replum, highlighting potential functional interactions. The expression of the RLCKVI_A2 gene from the constitutive 35S promoter could not complement the rpl-4 phenotypes but exhibited a dominant positive effect on stem growth and affected vascular differentiation and organization. The results also indicated that the number of vascular bundles is regulated independently from stem thickness. Although our study cannot demonstrate a direct link between the RPL and RLVKVI_A2 genes, it highlights the significance of the proper developmental regulation of the RLCKVI_A2 promoter for balanced stem development.