Search Results (41)

The lodging of wheat has a significant impact on its yield, and its resistance is intricately associated with the mechanical strength of its stem. The majority of existing studies on this issue have been conducted at the macroscale, and the quantitative relationship between cellular structural characteristics and the mechanical strength of the wheat stem remains poorly understood. This study aimed to investigate this relationship in two wheat cultivars: ‘Zhoumai 36’ and ‘Angong 38’. Samples were collected from the second basal internode of stems at three growth stages: anthesis, grain filling, and maturity. Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD) were utilized to examine cellular morphology, measure cell wall thickness, and analyze microfibril angles and crystallite sizes within the cell walls. Tensile tests were conducted to determine the tensile strength and elastic modulus of the stem samples. The relationship between cellular structural characteristics and stem mechanical strength was systematically investigated. The results demonstrated that during the developmental transition from anthesis to maturity, the elastic modulus of the stems in the two wheat varieties exhibited divergent trends: a decrease from 1.60 ± 0.08 GPa to 1.25 ± 0.04 GPa (mean ± SEM) in ‘Zhoumai 36’ and an increase from 1.15 ± 0.07 GPa to 1.48 ± 0.18 GPa (mean ± SEM) in ‘Angong 38’ These differences were accompanied by variations in water content between the two varieties. Furthermore, it was observed that the thickness of the S2 layer (the middle layers of the secondary cell wall) in both sclerenchyma and vessel cells showed a positive correlation with stem elastic modulus. Conversely, the microfibril angle of the S2 layer displayed a negative correlation with elastic modulus. Cellulose crystallite size varied across the growth stages, ranging from 1.22 ± 0.10 nm to 1.83 ± 0.30 nm (mean ± SEM) in ‘Zhoumai 36’ and from 1.42 ± 0.11 nm to 1.85 ± 0.23 nm (mean ± SEM) in ‘Angong 38’, respectively, and this parameter also exhibited a positive correlation with elastic modulus. This study clarified the variation trends of stem elastic modulus in wheat cultivars ‘Zhoumai 36’ and ‘Angong 38’ from anthesis to maturity and revealed, through experimental determination and correlation analysis, the microscale quantitative relationships between the stem cellular structural characteristics (S2 layer thickness, S2 layer microfibril angle, and cellulose crystallite size) and mechanical strength (characterized by elastic modulus) in the two cultivars. Full article

Melon (Cucumis melo L.) is an economically important horticultural crop worldwide, while its production is continuously endangered by powdery mildew (PM), a fungal disease mainly caused by Podosphaera xanthii, due to the insufficiency of disease resistant germplasms. Here, a melon recombinant inbred line (RIL) population that consisted of 188 independent individuals was obtained through the crossing of ‘SN-1’ (C. melon L. ssp. melo) and ‘YJM’ (C. melon L. ssp. agrestis), two parents with contrasting PM resistance, followed by 7-round selfings. Comprehensive phenotypic investigation revealed substantial variations in key agronomic traits among these RILs, such as stem diameters of 3.7~12.6 mm and internode lengths of 1.6~12.2 cm at the anthesis stage, as well as peduncle lengths of 0.5~9.5 cm and soluble solid content of 1.6~17.4% at the maturation stage. Particularly, 95 RILs, of which 60 and 35 belonged to thin-peel and netted types, respectively, were identified to be highly resistant to P. xnathii infection, providing new germplasms for melon improvement. Altogether, the generation of this melo-agrestis RIL population, together with the phenotypic observations, lays a solid foundation for mechanistic investigation of the traits with economic importance and could contribute to future breeding programs of melon cultivars with PM resistance. Full article

Late sowing and spring low temperatures have a great impact on the growth and maturation of wheat in the rice–wheat rotation region. In order to analyze the impacts of cold stress in February in early spring on yield formation and agronomic traits of wheat on different sowing dates, a controlled pot experiment was performed using the widely promoted and applied spring-type wheat variety Yangmai23 (YM23). The yield of wheat treated with late sowing date II (SDII, 21 November) and overly late sowing date III (SDIII, 9 December) were both lower than that of wheat sown on the suitable date I (SDI, 1 November). The yield of late-sown wheat decreased by 40.82% for SDII and by 66.77% for SDIII, compared with SDI, and these three treatments of wheat all grew under the natural conditions as the control treatments. The plant height, stem diameter of the internode below the ear, flag leaf length and area, and total awn length of the spike, as well as the spike length of late-sown wheat, were all significantly lower than those of wheat in SDI treatment. Early spring low temperatures exacerbated the decline in yield of wheat sown on different dates, to some extent. Despite showing higher net photosynthetic rate, stomatal conductance, and transpiration rate in flag leaves of the SDIII treatment under low-temperature stress than those of the other treatments at anthesis, overly late sowing led to minimal leaf area, shorter plant height, fewer tillers, and smaller ears, ultimately resulting in the lowest yield. Our study suggested that additional focus and some regulation techniques are needed to be studied further to mitigate the combined negative impacts of late sowing and low-temperature stress in early spring on wheat production. Full article

Malania oleifera Chun & S.K. Lee, an endemic monotypic species that belongs to the family Olacaceae, is under continuous pressure of decline owing to several ecological and physiological factors. The present study aimed to establish an efficient in vitro protocol for callus-mediated indirect somatic embryogenesis in M. oleifera by alleviating tissue browning. Internodes and leaves obtained from seedlings were used as explants. Antioxidant pre-treatment (ascorbic acid, AA) followed by different carbon sources (sucrose, maltose, glucose, and fructose) and plant growth regulators in various concentrations and combinations were employed in Woody Plant Medium (WPM) to alleviate explant browning and induce callus formation from the explants. AA pre-treatment and subsequent culture on maltose at a concentration of 116.8 mM were optimal for controlling phenolic exudation on >90% of both explants. The highest responses of 53.77% and 57.43% for embryogenic calli were induced from internode and leaf explants, respectively. The highest responses, 85.22% and 93.80%, were observed for somatic embryos that matured into the globular, heart-shaped and torpedo stages at different percentages on NAA 2.5 mg/L in combination with BA 1.0 mg/L for both explants. The matured somatic embryos were finally germinated at a maximum concentration of GA₃, 2.0 mg/L. All plantlets were successfully hardened and acclimatized under culture room conditions and then transferred to the greenhouse. The current study suggests an efficient protocol for indirect somatic embryogenesis by alleviating phenolic exudation from the explants of M. oleifera. This first successful report of in vitro culture establishment in M. oleifera may offer an effective alternative measure to conserve this species and provide a system for analyzing bioactive chemicals and for use in the oil industry. Full article

Understanding how transcription factors regulate biomass accumulation and sucrose storage is essential for improving sugarcane productivity. In this study, we quantified transcription factor protein (TFP) abundance in sugarcane internodes across developmental stages and growth rates. These profiles were correlated with key biochemical traits, including lignin, glucan, hemicellulose, and sucrose content. From 7333 identified proteins, 205 were annotated as transcription factors spanning 22 families. By applying Pearson correlation followed by Partial Correlation with Information Theory (PCIT), we identified 46 high-confidence TFP-trait associations. Key regulators, such as ScMYB113, ScMADS15, and ScbZIP85, exhibited trait-specific roles, influencing sucrose storage and cell wall biosynthesis. Network topology revealed distinct transcriptional modules linked to biomass production, polysaccharide deposition, and intermediary metabolism. Notably, sucrose and lignin accumulation intensified after internode elongation ceased, highlighting shifts in transcriptional control during maturation. This study delivers the first protein-level regulatory map linking transcription factors to metabolic traits in sugarcane and provides a framework for targeting candidate regulators to enhance biomass quality and yield in bioenergy crops such as sugarcane. Full article

The secondary lateral meristem—the vascular cambium (hereafter cambium)—is the largest meristem of the plant kingdom. It is almost always composed of two types of stem cells: (1) the axial (fusiform) initials, the most common and better known and studied, and (2) the ray initials that give rise to the vascular rays (hereafter rays), i.e., the radial component of the secondary xylem and phloem, which are less common and much less studied, and in many studies ignored. There is great flexibility in switching from axial initials to ray initials and vice versa. Ray initials commonly compose ca. 10–40% of the cambium of mature tree trunks, but nothing or very little in typical young model plants used for molecular cambial studies, such as Arabidopsis thaliana and young internodes of Populus spp. cuttings. I suggest paying more attention to the regulation of the differentiation of ray initials and their derivatives, and to the little-known complicated relations between the axial and ray cambial initials when they contact each other, as well as the special development of pits in their derivatives in cambial molecular studies by using mature trunks of various large woody plants rather than studying A. thaliana or young internodes of Populus cuttings. Full article

Lepidium sativum, commonly known as garden cress, is a notable traditional medicinal plant within the Brassicaceae family, widely recognized for its health benefits in the globe. This study aimed to identify the seed colour variant best suited to the climate of Ethiopia, specifically in the Ataye region, by examining various agronomic traits. We conducted a comprehensive analysis of two distinct seed colour variants (brown and light blue) following standard agronomic protocols. Results indicated that the brown seed variant outperformed the light blue variant across multiple agronomic traits, demonstrating a shorter time to 50% germination, flowering, and maturation. Statistically significant differences were observed in these parameters. Additionally, plants derived from brown seeds exhibited superior growth characteristics, including greater plant height, longer primary branch length, and a higher number of primary branches per plant compared to those from light blue seeds. Furthermore, the brown seed variant displayed increased productivity, with more pods and seeds per plant, a greater one thousand seed weight, and a higher overall yield. The only traits showing no significant differences were the number of secondary branches per plant and internode length. Overall, the brown seed variant demonstrated strong adaptability to the Ataye climatic conditions, excelling in yield per hectare as well as in the number of seeds and pods produced. Based on these findings, we recommend the cultivation of brown seed colour variants for optimal performance in Ataye region, Ethiopia. Full article

Stem lodging is a serious problem for the ripe barley crop because it can reduce grain yield and quality. Although biometrical traits (stem diameter and wall thickness) and mechanical properties (stiffness and strength of the culm) have an obvious role in determining lodging resistance, they have only a partial capability to predict lodging resistance. We, therefore, investigated how factors like stem wetting and the point of application of the bending force affect the assessment of these traits. A three-point bending test using a height gauge can provide measures of bending strength (B_S), material strength (σ_b), modulus of elasticity (E), and stiffness (EI). Since the first two parameters are of greatest interest, a quick manual method for measuring them is proposed. We used it specifically to compare the results of tests made by loading the bending force either on the node or the internode. It was shown that the pulvinus (which forms a complex with the node) is the weak point for mechanical resistance to bending in ripe barley stems, as a drop in B_S between −31% and −41% (depending on whether the stems were dry or wet) was observed when the loading force was applied on the node/pulvinus complex with respect to the internode. We also found that, overall, B_S plummeted −62% with respect to dry stems when the stems were wetted. This was due to an equivalent (−62%) plunge in σ_b. Similar drops in B_S (−64%) and σ_b (−68%) following wetting were measured with the height gauge. Wetting, therefore, greatly lowers the mechanical resistance of stems. Moreover, the existence of a weak point—i.e., the pulvinus—in mature barley stems is an important feature that must be considered when evaluating the lodging-related characteristics of this crop. These findings improve our understanding of the mechanical properties of barley stems and, thus, our capability to identify genotypes with better lodging resistance. Full article

Ethylene-insensitive 3/Ethylene-insensitive3-like proteins (EIN3/EIL) represent a group of transcription factors critical for the ethylene signaling transduction that manipulate downstream ethylene-responsive genes, thereby regulating plant growth, development, and stress responses. However, the identification, evolution, and divergence of the EIL family remain to be studied in Sorghum bicolor. Here, we identified eight SbEILs, which were expanded due to whole-genome-duplication (WGD) events. Characterization of the protein sequences and expression atlas demonstrates that the WGD-duplicated SbEILs could become divergent due to the differential expression patterns, rather than domain and motif architectures. Comparative expression analysis was performed between the RNA-seq data sets of internodes from several sorghum cultivars to understand the potential roles of SbEIL members in internode elongation and maturation. Our results identified SbEIL3 and 7 (the latter as a homolog of OsEIL7/OsEIL1) to be the highly expressed SbEIL genes in sorghum internodes and revealed a potential functional link between SbEIL7 and internode maturation. The co-expression analysis and comparative expression analysis with ethylene-regulated gene sets found that SbEIL7 was co-regulated with a set of ubiquitin-related protein degradation genes, suggesting possible involvement of SbEIL7 in protein degradation and processing during the post-anthesis stages. Altogether, our findings lay a foundation for future functional studies of ethylene signaling-mediated gene regulation and improvement of sorghum internode development. Full article

Growth-regulating factor (GRF) is a plant-specific family of transcription factors crucial for meristem development and plant growth. Sorghum (Sorghum bicolor L. Moench) is a cereal species widely used for food, feed and fuel. While sorghum stems are important biomass components, the regulation of stem development and the carbohydrate composition of the stem tissues remain largely unknown. Here, we identified 11 SbGRF-encoding genes and found the SbGRF expansion driven by whole-genome duplication events. By comparative analyses of GRFs between rice and sorghum, we demonstrated the divergence of whole-genome duplication (WGD)-derived OsGRFs and SbGRFs. A comparison of SbGRFs’ expression profiles supports that the WGD-duplicated OsGRFs and SbGRFs experienced distinct evolutionary trajectories, possibly leading to diverged functions. RNA-seq analysis of the internode tissues identified several SbGRFs involved in internode elongation, maturation and cell wall metabolism. We constructed co-expression networks with the RNA-seq data of sorghum internodes. Network analysis discovered that SbGRF1, 5 and 7 could be involved in the down-regulation of the biosynthesis of cell wall components, while SbGRF4, 6, 8 and 9 could be associated with the regulation of cell wall loosening, reassembly and/or starch biosynthesis. In summary, our genome-wide analysis of SbGRFs reveals the distinct evolutionary trajectories of WGD-derived SbGRF pairs. Importantly, expression analyses highlight previously unknown functions of several SbGRFs in internode elongation, maturation and the potential involvement in the metabolism of the cell wall and starch during post-anthesis stages. Full article

Hybrid rice needs to prevent lodging due to excessive grain weight during maturity, which can lead to yield loss, grain quality deterioration and difficulty in harvesting. Breeding excellent parents (restorer and male-sterile lines) is the foundation for cultivating lodging-resistant hybrid rice. However, there is still limited information about restorers with improved lodging resistance. To identify a new restorer with significantly enhanced resistance to lodging, the restorer line Huazhan, which has been used for many years in hybrid rice breeding in China, was used as the control, to evaluate the lodging resistance of the new restorer R382. A two-year field experiment was executed to investigate the difference on lodging-related traits of the basal two internodes above-ground, such as out diameters of stems with or without leaf sheath (DWS, DWOS), culm thickness (CT), the section modulus (SM), bending stress (BS), and bending moment at break (M). The results indicated that DWS, CT, BS, M of R382 was at least 19.9%, 13.3%, 36.5% and 52.6% higher than that of Huazhan. However, the negative indicator lodging index of R382 was over 17.5% lower. The number and area of vascular bundles, and the contents of the chemical components of the cell wall including cellulose, lignin, and hemicellulose, together with the accumulation of starch granules, were significantly greater in R382. Furthermore, in the basal stems during the jointing stage, a series of genes that promote cell wall formation exhibited significantly higher expression levels in R382. Meanwhile, there was no significant difference in the yield of R382 and Huazhan. Thus, this new restorer could be a valuable donor in the future hybrid rice breeding programs for improving lodging resistance. Full article

To determine the patterns and influencing factors of the mechanical properties of millet stems from different varieties during the maturity period, this study employed a complete block experiment method and conducted shearing and bending tests on millet stems using the INSTRON5544 electronic universal material testing machine. The research investigated the variation in the shear strength, specific shear energy, bending strength, elastic modulus, and bending stiffness at different internode positions of the stems of Changza 466, Zhangza 16, and Jingu 21 during their maturity period. The results indicated that the variety had a significant impact on the mechanical properties of millet stems: from largest to smallest, the order of shear and bending forces was Jingu 21, Zhangza 16, and Changza 466. The shear strength and bending strength of Jingu 21 were the greatest among the three stem samples. The internode position significantly affected the shear mechanical properties of the millet stems, showing a general trend of decreasing shear strength with ascending internode position. The effect of the internode position on the bending stiffness was highly significant, whereas its impact on the bending strength and elastic modulus was not significant. The shear strength of the millet stems ranged from 3.866 ± 1.086 to 6.953 ± 2.208 MPa, significantly lower than the bending strength, which ranged from 18.934 ± 4.374 to 34.286 ± 6.875 MPa. The lowest shear strength and specific shearing energy, recorded at the fifth internode, were 4.028 ± 1.918 MPa and 15.097 ± 12.633 MJ/mm², respectively. Jingu 21 and Changza 466 exhibit better lodging resistance than Zhangza 16. It is recommended to use a cutting-type platform for harvesting millet stems, with the cutting height set at the fifth internode position. This study provides a theoretical basis for the design of millet harvesting machinery and the selection of harvest parameters. Full article

Low-cadmium (Cd) accumulating wheat cultivars (LAWC-Cds) can effectively reduce the total Cd content in wheat grains (Grain-Cd). Thirteen LAWC-Cds were planted in three fields to study the enrichment, transport, and accumulation patterns of Cd in LAWC-Cds. Compared with the soil properties before planting, the soil pH and the total Cd content in the soil decreased, while the Cd content in the diethylenetriaminepentaacetic acid extract, soil conductivity, and soil organic matter increased at wheat maturity. The Cd enrichment capacity of the different organs of wheat decreased in the following order: root > leaf > rachis > stem > glume > grain. The dynamics of Cd accumulation in roots affected Grain-Cd, and these factors were negatively correlated. The Cd content and Cd accumulation in all organs of LAWC-Cds showed strong negative correlations with the lengths of the first and second internodes and highly significant positive correlations with both grains per spike and awn length. Structural equation modeling showed that the Cd content of wheat organs had the most direct effect (0.639) in determining Grain-Cd, and soil properties had the largest effect (0.744) in influencing Grain-Cd. This study is important for screening wheat cultivars with stable low Cd-accumulation characteristics. Full article

Sugarcane is a significant primitive source of sugar and energy worldwide. The progress in enhancing the sugar content in sugarcane cultivars remains limited due to an insufficient understanding of specific genes related to sucrose production. The present investigation examined the enzyme activities, levels of reducing and non-reducing sugars, and transcript expression using RT-qPCR to assess the gene expression associated with sucrose metabolism in a high-sucrose sugarcane clone (GXB9) in comparison to a low-sucrose sister clone (B9). Sucrose phosphate synthase (SPS), sucrose phosphate phosphatase (SPP), sucrose synthase (SuSy), cell wall invertase (CWI), soluble acid invertase (SAI), and neutral invertase (NI) are essential enzymes involved in sucrose metabolism in sugarcane. The activities of these enzymes were comparatively quantified and analyzed in immature and maturing internodes of the high- and low-sucrose clones. The results showed that the higher-sucrose-accumulating clone had greater sucrose concentrations than the low-sucrose-accumulating clone; however, maturing internodes had higher sucrose levels than immature internodes in both clones. Hexose concentrations were higher in immature internodes than in maturing internodes for both clones. The SPS and SPP enzymes activities were higher in the high-sucrose-storing clone than in the low-sucrose clone. SuSy activity was higher in the low-sucrose clone than in the high-sucrose clone; further, the degree of SuSy activity was higher in immature internodes than in maturing internodes for both clones. The SPS gene expression was considerably higher in mature internodes of the high-sucrose clones than the low-sucrose clone. Conversely, the SuSy gene exhibited up-regulated expression in the low-sucrose clone. The enhanced expression of SPS in the high-sucrose clone compared to the low-sucrose clone suggests that SPS plays a major role in the increased accumulation of sucrose. These findings provide the opportunity to improve sugarcane cultivars by regulating the activity of genes related to sucrose metabolism using transgenic techniques. Full article

The application of beneficial microbial consortium can effectively improve plant disease resistance and its growth. Various fungi were compounded with Bacillus velezensis LJ02 and applied to watermelon plants in this paper. The results showed that the microbial consortium T2 (compounded Bacillus velezensis LJ02 with Aspergillus aculeatus 9) can effectively control gummy stem blight and powdery mildew in watermelon, while the control effect reached 83.56% and 70.93%, respectively (p < 0.05). Compound treatment improved the diversity and richness of the rhizosphere microbial community structure, and the relative abundance of Caulobacterales and Xanthomonadaceae significantly increased after applying T2 to the soil. Meanwhile, the internode length was significantly decreased 28% (p < 0.05), and the maximum leaf length increased 10.33% (p < 0.05). In addition, the microbial consortium delays the maturity of watermelon vegetables. By studying the effects of microbial consortium on watermelon seedlings, our study provides a theoretical basis for the popularization and application of the compound inoculant. Full article