Leaf Formation Research Articles

Effects of acute gamma irradiation on the morphology of Curcuma alismatifolia ‘Siam Shadow’ and C. alismatifolia ‘Siam Scarlet’

Curcuma alismatifolia (Pathumma in Thailand), also known as Siam Tulip, is an economically valuable cut flower in Thailand and is continuously bred to enhance its captivating array of colors. This study aimed to investigate the effects of acute gamma irradiation on 2 cultivars of C. alismatifolia ‘Siam Shadow’ and C. alismatifolia ‘Siam Scarlet’ for in vitro propagation and determination of the lethal dose 50 (LD50). The irradiation was conducted at doses of 0, 20, 30, 40 and 80 Gy using young shoots tissue culture. The results of the experiment revealed that the LD50 for ‘Siam Shadow’ could not be determined while ‘Siam Scarlet’ was 29.06 Gy. ‘Siam Shadow’ exhibited chimera leaf formation when exposed to a gamma irradiated dose of 40 Gy, while ‘Siam Scarlet’ exhibited chimera leaf formation when gamma irradiated at doses of 20 Gy in vitro. After planting in a greenhouse, ‘Siam Shadow’ was irradiated with 30 Gy of gamma irradiated, had reduced bract numbers and the bracts became smaller. Conversely, ‘Siam Scarlet’ irradiated with 20 Gy of gamma irradiated, produced smaller inflorescences with only 2 bracts, while irradiation with 30 Gy resulted in 2 lobes and spotted leaves at the edges of the leaves. The results indicated that both the C. alismatifolia cultivars and gamma irradiation rates had a significant influence on survival rate, number of shoots, plant height, chlorophyll mutants and morphology. As the outcome, it was determined that gamma irradiation with optimum doses of gamma rays could induce new characteristics in C. alismatifolia.

Plant biotechnology for the conservation of Argania spinosa (Skeels L): optimising propagation and sustainable valorisation

ABSTRACT Argania spinosa, an endangered species from southwestern Morocco, is studied for preservation through plant biotechnology. The research aims to optimise argan tree propagation to boost production, preserve heritage, and use residual species. In vitro seedlings are transferred to a modified Murashige and Skoog medium with various phytohormones. Six combinations of auxins and cytokinins are tested for germination. Results show that a liquid medium with activated charcoal from argan shells promotes stem elongation. Meta-topoline at 0.5 mg L−1, combined with naphthalene acetic acid (NAA) at 0.2 mg L−1, enhances shoot growth, leaf formation, and callogenesis. Adding benzylaminopurine (BAP) at 0.1 mg L−1 and indole-3-butyric acid (IBA) at 0.02 mg L−1 to the medium elongates stems by 4.3 cm after 21 days. A 2000 ppm IBA concentration is key for a 90% rooting rate. These findings underscore plant biotechnology’s role in preserving and propagating argan trees, improving resource management, and supporting sustainability.

The Effects of Auxin Transport Inhibition on the Formation of Various Leaf and Vein Patterns.

Polar auxin transport (PAT) is a known component controlling leaf complexity and venation patterns in some model plant species. Evidence indicates that PAT generates auxin converge points (CPs) that in turn lead to local leaf formation and internally into major vein formation. However, the role of PAT in more diverse leaf arrangements and vein patterns is largely unknown. We used the pharmacological inhibition of PAT in developing pinnate tomato, trifoliate clover, palmate lupin, and bipinnate carrot leaves and observed dosage-dependent reduction to simple leaves in these eudicots. Leaf venation patterns changed from craspedodromous (clover, carrot), semi-craspedodromous (tomato), and brochidodromous (lupin) to more parallel patterning with PAT inhibition. The visualization of auxin responses in transgenic tomato plants showed that discrete and separate CPs in control plants were replaced by diffuse convergence areas near the margin. These effects indicate that PAT plays a universal role in the formation of different leaf and vein patterns in eudicot species via a mechanism that depends on the generation as well as the separation of auxin CPs. Computer simulations indicate that variations in PAT can alter the number of CPs, corresponding leaf lobe formation, and the position of major leaf veins along the leaf margin in support of experimental results.

Phosphate solubilization potential of PSB: an advance approach to enhance phosphorous availability for phytostimulation.

Rhizosphere engineering approach is considered a quantum leap in plant sciences. The current study focused on investigating rhizobacterial efficiency to mobilize bioavailable phosphate from insoluble-phosphate source. Four efficient phosphate-solubilizing bacterial isolates, i.e., Pseudomonas songnenensis (GR3), Stutzerimonas stutzeri (HH2), Bacillus bingmayongensis (KH3), and Achromobacter aegrifaciens (MH1) were selected for the current study. Interactions between various physiological parameters and phosphate solubilization efficiency of isolates revealed that glucose significantly facilitated phosphorus solubilization at 37 ℃, with media having pH 7 and 0.5% phosphorous. Additionally, positive correlation among P-solubilization potential, acids produced, and pH was observed. Plant microbe-interaction analysis was performed to evaluate the efficiency of these bacterial isolates on various morpho-physiological responses of Zea mays L. For this purpose, various concentrations of tricalcium phosphate (TCP) (0, 10, 20, 30, 40, and 50mM) were applied to plants in the presence and absence of bacterial isolates. The results showed that lower phosphate levels (10 and 20mM) trigger shoot development and improve plant weight and leaf formation whereas higher phosphate concentrations (30mM and above) stimulated the development of longer root system. The bacterial isolates, KH3 and HH2, were observed as efficient phosphate-solubilizing bacteria (PSB) that positively stimulated various plant growth and biochemical attributes over untreated plants. At lower phosphate levels, substantial increase of 92, 65, and 200% in shoot length, fresh weight, and number of leaves was recorded with bacterial isolate HH2, whereas, at 30mM TCP, increase of 165% was observed in root length of plants treated with bacterial isolate KH3 compared to control. Similarly, at lower phosphate levels, increment of 57.3, 76.7, and 217% in phosphate, protein, and auxin content was recorded in plants treated with bacterial isolate HH2, and increase of 188.8% in total soluble carbohydrates was observed in plants treated with bacterial isolate KH3 as compared to control. Contrarily, increment in total chlorophyll content was most substantial (207%) by the bacterial isolate KH3 when provided with 30mM TCP. Hence, the current study reviled that the use of these phosphates (KH3 and HH2)-solubilizing PGPR, as an efficient phytostimulator used for crop production in the replacement of chemical fertilizers, is carcinogenic and deteriorating our eco-system.

Far-red light enrichment affects gene expression and architecture as well as growth and photosynthesis in rice.

Plants use light as a resource and signal. Photons within the 400-700 nm waveband are considered photosynthetically active. Far-red photons (FR, 700-800 nm) are used by plants to detect nearby vegetation and elicit the shade avoidance syndrome. In addition, FR photons have also been shown to contribute to photosynthesis, but knowledge about these dual effects remains scarce. Here, we study shoot-architectural and photosynthetic responses to supplemental FR light during the photoperiod in several rice varieties. We observed that FR enrichment only mildly affected the rice transcriptome and shoot architecture as compared to established model species, whereas leaf formation, tilleringand biomass accumulation were clearly promoted. Consistent with this growth promotion, we found that CO2-fixation in supplemental FR was strongly enhanced, especially in plants acclimated to FR-enriched conditions as compared to control conditions. This growth promotion dominates the effects of FR photons on shoot development and architecture. When substituting FR enrichment with an end-of-day FR pulse, this prevented photosynthesis-promoting effects and elicited shade avoidance responses. We conclude that FR photons can have a dual role, where effects depend on the environmental context: in addition to being an environmental signal, they are also a potent source of harvestable energy.

Mycotoxins in vegetating corn plants from experimental mono-sowing

The aim of present study was to reveal the mycotoxin contamination of vegetative maize (Zea mays L.) plants during the periods of leaf formation and panicle emergence. Early maturing hybrids of the varieties Krasnodarsky 194 MV, Ladozhsky 175 MV and Competence®, resistant to fungal diseases, were grown in the spring-summer period of 2023 on the experimental field of the Russian State Agrarian University – Moscow Agricultural Academy (Moscow) with sod-podzolic soil and the application of NPK fertilizers 16:16:16. For mycotoxicological analysis, aerial parts of plants were collected weekly from the phase of formation of the 3rd leaf (18 days after sowing. Samples of seedlings, leaves and stems (total number – 172), after drying, were ground in a laboratory mill and extracted with a mixture of acetonitrile and water in a volumetric ratio of 84:16 with a consumption of 10 ml per 1 g of sample. Mycotoxin content was determined in extracts after 10-fold dilution with phosphate-salt buffer solution pH 7.5 by indirect competitive enzyme immunoassay. T-2 toxin, deoxynivalenol, diacetoxiscirpenol, roridin A, sterigmatocystin and PR toxin were absent in the samples. Corn seedlings and leaves contained cyclopiazonic acid (CPA), emodin (EMO), mycophenolic acid (MPA), alternariol (AOL), ergot alkaloids (EA), aflatoxin B1 (AB1) and single samples – zearalenone (ZEN), ochratoxin A (OA) and citrinin (CIT) in concentrations from 16 up to 35 μg/kg. Fumonisins of group B are found only in early seedlings. The permanent contaminant of the stems was MPA, whereas EA and CIT were absent. In the seedlings and leaves of all hybrids, the detection of AOL and EA remained stable during the change of development phases, as did the average concentrations of CPA (about 100 μg/kg), AOL (from 17 to 27 μg/kg), EMO (35–58 μg/kg), MPA (28–41 μg/kg), EA (6–18 μg/kg) and AB1 (2 μg/kg). In the stems of plants in phases 7–9 of leaf and sweeping, variation in cases of detection of CPA, EMO, AOL, AB1 and OA was noted by varieties.

Association analysis of BSA-seq, BSR-seq, and RNA-seq reveals key genes involved in purple leaf formation in a tea population (Camellia sinensis).

Purple tea, rich in anthocyanins, has a variety of health benefits and is attracting global interest. However, the regulation mechanism of anthocyanin in purple tea populations has not been extensively studied. In this experiment, RNA-seq, BSA-seq, and BSR-seq were performed using 30 individuals with extreme colors (dark-purple and green) in an F 1 population of 'Zijuan' and 'Jinxuan'. The results show that 459 genes were differentially expressed in purple and green leaves, among which genes involved in the anthocyanin synthesis and transport pathway, such as CHS, F3H, ANS, MYB75, GST, MATE, and ABCC, were highly expressed in purple leaves. Moreover, there were multiple SNP/InDel variation sites on chromosomes 2 and 14 of the tea plant, as identified by BSA-seq. The integrated analysis identified two highly expressed genes (CsANS and CsMYB75) with SNP/InDel site variations in the purple tea plants. By silencing leaves, we proved that CsMYB75 could positively regulate anthocyanin accumulation and expression of related structural genes in tea plants. A 181-bp InDel in the CsMYB75 promoter was also found to be co-segregating with leaf color. The results of this study provide a theoretical reference for the molecular mechanism of anthocyanin accumulation in purple tea plants and contribute to the creation of new tea cultivars with high anthocyanin content.

Temperature and LED lightning affect the regeneration of somatic embryo-derived sporophytes on the internode explants of the tree fern Cyathea delgadii Sternb.

The influence of the temperature and different light qualities emitted by light-emitting diodes (LEDs) and fluorescent lamps (Fl) on the micropropagation of the tree fern Cyathea delgadii was evaluated. The most efficient somatic embryo production was obtained on internode explants at 22 °C. The optimal temperature range for obtaining well-developed plants was 24–28 °C. This stimulated the elongation and development of the first leaf and the formation of the next leaf and roots primordia. Temperatures lower than 24 °C and higher than 28 °C inhibited the formation of young sporophyte organs and delayed their development. The RBUV (35% red, 15% blue, and 50% UV) and B (100% blue) lights and Fl light were beneficial for the sporophyte production on internode explants. However, plants obtained under RBUV light were undeveloped. The white LED light stimulated the number of explants capable of gametophyte production and development. The RB light (70% red and 30% blue) enhanced the number of roots of newly-formed plants. Most of the LED lights tested had a good impact on root elongation compared to Fl light and constant darkness. The R light (100% red) benefits leaf development and elongation. Research shows that temperature and LED lightning play a significant role in the process of morphogenesis in C. delgadii, significantly affecting the embryogenic competence of somatic cells and the development of sporophytes.

Temporal dynamics of chloroplast biogenesis revealed initiation of photosynthesis-related gene expression and protein complexes during alfalfa seed germination

The chloroplast biogenesis occurs in cotyledon during alfalfa seed germination before true leaf formation, and is extremely important for the followed plant development and growth. In this study, we conducted a simulation of alfalfa seed germination in the soil by using tin foil and focused on 10 pivotal time points of chloroplast biogenesis in cotyledons before and after light exposure, which showed significant differences in multispectral images, and covered the whole process of chloroplast biogenesis from proplastid, etioplast to mature chloroplast. We revealed three phases that referred to the programmed involvements of photosynthesis promotion, ultrastructure maturity, transcriptomic expression, and protein complex construction, and observed distinct transcriptional expressions of genes from nuclear and chloroplast genomes. In phase I at dark germination before light exposure, chloroplast-encoded genes showed up-regulated expressions together with the importation of chloroplast proteins. In phase II for the first day after light exposure, nuclear-encoded genes’ expressions were initiated at 2 h after light exposure (E2h), followed by swift assembly of chloroplast thylakoid membrane protein complexes, and roaring Fv/Fm and contents of chlorophyll a, chlorophyll b and carotenoid. The initiation at E2h was pronounced by the observation of gradual accumulation of single lamella, and facilitated the formation of granum stacks (thylakoid) at E8h in phase II. In phase III from the second day after light exposure, chloroplast became gradually complete with the fully established photosynthetic capacity. Altogether, our results layed a theoretical foundation for enhancing potential photosynthetic efficiency in alfalfa and related species.

The contest between artificial management and natural environment determines the adaptive strategies of leaf morphogenesis in Sabina chinensis.

Sabina chinensis is a typically heteromorphic leaf evergreen tree worldwide with both ornamental and ecological value. However, the shaping mechanism of heteromorphic leaves of S. chinensis and its adaptability to environment are important factors determining its morphology. The morphological change of S. chinensis under different habitats (tree around) and treatments (light, pruning and nutrients) was investigated. Our findings suggested that the prickle leaves proportion was associated with low light intensity and soil nutrient scarcity. Stems and leaves are pruned together to form clusters of large prickle leaves, while only pruning leaves often form alternately growing small prickle leaves and scale leaves, and the length of the prickle leaves is between 0.5 cm and 1 cm. The gene expression of prickle leaves is higher than that of scale leaves under adverse environmental conditions, and the gene expression correlations between small prickle leaf and scale leaf were the highest. Homologous and heterologous mutants of gene structure in prickle leaves were larger than those in scale leaves. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway showed that phenylpropanone and flavonoid biosynthesis were common enrichment pathways, and that the enrichment genes were mainly related to metabolism, genetic information processing and organismal systems. Therefore, we concluded that the occurrence of the heteromorphic leaf phenomenon was related to the changes in photosynthesis, mechanical damage and nutrient supplementation. The organic matter in the S. chinensis prickle leaves was reduced under environmental stresses, and it will be allocated to the expression of prickle leaf or protective cuticles formation.

Genomic analysis of a spontaneous unifoliate mutant reveals gene candidates associated with compound leaf development in Vigna unguiculata [L] Walp

Molecular mechanisms which underpin compound leaf development in some legumes have been reported, but there is no previous study on the molecular genetic control of compound leaf formation in Vigna unguiculata (cowpea), an important dryland legume of African origin. In most studied species with compound leaves, class 1 KNOTTED-LIKE HOMEOBOX genes expressed in developing leaf primordia sustain morphogenetic activity, allowing leaf dissection and the development of leaflets. Other genes, such as, SINGLE LEAFLET1 in Medicago truncatula and Trifoliate in Solanum lycopersicum, are also implicated in regulating compound leaf patterning. To set the pace for an in-depth understanding of the genetics of compound leaf development in cowpea, we applied RNA-seq and whole genome shotgun sequence datasets of a spontaneous cowpea unifoliate mutant and its trifoliate wild-type cultivar to conduct comparative reference-based gene expression, de novo genome-wide isoform switch, and genome variant analyses between the two genotypes. Our results suggest that genomic variants upstream of LATE ELONGATED HYPOCOTYL and down-stream of REVEILLE4, BRASSINOSTERIOD INSENSITIVE1 and LATERAL ORGAN BOUNDARIES result in down-regulation of key components of cowpea circadian rhythm central oscillator and brassinosteroid signaling, resulting in unifoliate leaves and brassinosteroid-deficient-like phenotypes. We have stated hypotheses that will guide follow-up studies expected to provide more insights.

Mutations of PsPALM1a and PsPALM1b associated with the afila phenotype in Pea.

Semi-leafless represents an advantageous plant architecture in pea breeding due to its ability to enhance resistance to lodging and potentially to powdery mildew. The introduction of semi-leafless pea varieties is considered a seminal advancement in pea breeding over the past half-century. The afila (af) mutation leads to the replacement of lateral leaflets by highly branched tendrils; combined with the semi-dwarfing le mutation, it forms the semi-leafless cultivated variety. In this study, we identified that mutations in two tandemly-arrayed genes encoding Cys(2)His(2) zinc finger transcription factors, PsPALM1a and PsPALM1b, were closely associated with the afila phenotype. These two genes may be deleted in the af mutant. In situ hybridization showed that both genes exhibit specific expression in early leaflet primordia. Furthermore, suppression of PsPALM1a/PsPALM1b resulted in a high frequency of conversion of lateral leaflets into tendrils. In conclusion, our study provides genetic evidence demonstrating that mutations in PsPALM1a and PsPALM1b are responsible for the af locus, contributing to a better understanding of compound leaf formation in peas and offering new insights for breeding applications related to afila.

QTL mapping for the flag leaf-related traits using RILs derived from Trititrigia germplasm line SN304 and wheat cultivar Yannong15 in multiple environments

BackgroundDeveloping and enriching genetic resources plays important role in the crop improvement. The flag leaf affects plant architecture and contributes to the grain yield of wheat (Triticum aestivum L.). The genetic improvement of flag leaf traits faces problems such as a limited genetic basis. Among the various genetic resources of wheat, Thinopyrum intermedium has been utilized as a valuable resource in genetic improvement due to its disease resistance, large spikes, large leaves, and multiple flowers. In this study, a recombinant inbred line (RIL) population was derived from common wheat Yannong15 and wheat-Th. intermedium introgression line SN304 was used to identify the quantitative trait loci (QTL) for flag leaf-related traits.ResultsQTL mapping was performed for flag leaf length (FLL), flag leaf width (FLW) and flag leaf area (FLA). A total of 77 QTLs were detected, and among these, 51 QTLs with positive alleles were contributed by SN304. Fourteen major QTLs for flag leaf traits were detected on chromosomes 2B, 3B, 4B, and 2D. Additionally, 28 QTLs and 8 QTLs for flag leaf-related traits were detected in low-phosphorus and drought environments, respectively. Based on major QTLs of positive alleles from SN304, we identified a pair of double-ended anchor primers mapped on chromosome 2B and amplified a specific band of Th. intermedium in SN304. Moreover, there was a major colocated QTL on chromosome 2B, called QFll/Flw/Fla-2B, which was delimited to a physical interval of approximately 2.9 Mb and contained 20 candidate genes. Through gene sequence and expression analysis, four candidate genes associated with flag leaf formation and growth in the QTL interval were identified.ConclusionThese results promote the fine mapping of QFll/Flw/Fla-2B, which have pleiotropic effects, and will facilitate the identification of candidate genes for flag leaf-related traits. Additionally, this work provides a theoretical basis for the application of Th. intermedium in wheat breeding.

ANÁLISIS DEL CRECIMIENTO DE Carica papaya L. BAJO INFECCIÓN POR PRSV-P

<p><strong>Background.</strong> Papaya (<em>Carica papaya</em> L.) is cultivated in tropical and subtropical regions of the world for its nutritious and healthy fruits intended mainly for fresh consumption. Mexico was the world's leading papaya exporter in 2020 with 167,500 t. <em>C. papaya</em> is attacked by several viral diseases, the ring spot virus (PRSV-P) is the one that causes the most damage to the crop and the greatest production losses. <strong>Objective.</strong> To establish the phenology of a <em>Carica papaya</em> L. ‘Maradol Roja’ population infected with PRSV-P, to quantify its growth, and to relate its phenological steps with the accumulated degree days (DD). <strong>Methodology.</strong> The emissions of leaves, flower buds, flowers and fruits, apparent height of the plant, stem diameter and biomass were evaluated, based on the DD accumulated during the growth cycle. <strong>Results.</strong> The growth cycle is divided into nine phenological stages, where the leaf or flower bud formation requires ≈ 18 DD. In plants, the number of leaves is approximately equal to the number of flower buds. However, the number of ripe fruits is variable due to the adverse conditions that can occur throughout the growth period. To some extent, the roots typically present two growth peaks, although the available moisture in the soil could change this pattern. The apparent height of the plant and the stem diameter present a double sigmoid growth curve, with a maximum apparent height of 180 cm, and a diameter at the base of 11 cm. <strong>Implications.</strong> The infection by PRSV-P reduced the productivity and commercial quality of the fruits. <strong>Conclusions.</strong> PRSV-P infection reduced apparent height, stem diameter, number of leaves, flowers, and fruits, decrease in biomass gain, and shortened life cycle of plants.</p>

Rewiring of a KNOXI regulatory network mediated by UFO underlies the compound leaf development in Medicago truncatula

Class I KNOTTED-like homeobox (KNOXI) genes are parts of the regulatory network that control the evolutionary diversification of leaf morphology. Their specific spatiotemporal expression patterns in developing leaves correlate with the degrees of leaf complexity between simple-leafed and compound-leafed species. However, KNOXI genes are not involved in compound leaf formation in several legume species. Here, we identify a pathway for dual repression of MtKNOXI function in Medicago truncatula. PINNATE-LIKE PENTAFOLIATA1 (PINNA1) represses the expression of MtKNOXI, while PINNA1 interacts with MtKNOXI and sequesters it to the cytoplasm. Further investigations reveal that UNUSUAL FLORAL ORGANS (MtUFO) is the direct target of MtKNOXI, and mediates the transition from trifoliate to pinnate-like pentafoliate leaves. These data suggest a new layer of regulation for morphological diversity in compound-leafed species, in which the conserved regulators of floral development, MtUFO, and leaf development, MtKNOXI, are involved in variation of pinnate-like compound leaves in M. truncatula.

Integrated transcriptomic and metabolomic analyses reveals anthocyanin biosynthesis in leaf coloration of quinoa (Chenopodium quinoa Willd.)

BackgroundQuinoa leaves demonstrate a diverse array of colors, offering a potential enhancement to landscape aesthetics and the development of leisure-oriented sightseeing agriculture in semi-arid regions. This study utilized integrated transcriptomic and metabolomic analyses to investigate the mechanisms underlying anthocyanin synthesis in both emerald green and pink quinoa leaves.ResultsIntegrated transcriptomic and metabolomic analyses indicated that both flavonoid biosynthesis pathway (ko00941) and anthocyanin biosynthesis pathway (ko00942) were significantly associated with anthocyanin biosynthesis. Differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) were analyzed between the two germplasms during different developmental periods. Ten DEGs were verified using qRT-PCR, and the results were consistent with those of the transcriptomic sequencing. The elevated expression of phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), 4-coumarate CoA ligase (4CL) and Hydroxycinnamoyltransferase (HCT), as well as the reduced expression of flavanone 3-hydroxylase (F3H) and Flavonol synthase (FLS), likely cause pink leaf formation. In addition, bHLH14, WRKY46, and TGA indirectly affected the activities of CHS and 4CL, collectively regulating the levels of cyanidin 3-O-(3’’, 6’’-O-dimalonyl) glucoside and naringenin. The diminished expression of PAL, 4CL, and HCT decreased the formation of cyanidin-3-O-(6”-O-malonyl-2”-O-glucuronyl) glucoside, leading to the emergence of emerald green leaves. Moreover, the lowered expression of TGA and WRKY46 indirectly regulated 4CL activity, serving as another important factor in maintaining the emerald green hue in leaves N1, N2, and N3.ConclusionThese findings establish a foundation for elucidating the molecular regulatory mechanisms governing anthocyanin biosynthesis in quinoa leaves, and also provide some theoretical basis for the development of leisure and sightseeing agriculture.

Transcriptomic analyses to summarize gene expression patterns that occur during leaf initiation of Chinese cabbage.

In Chinese cabbage, rosette leaves expose their adaxial side to the light converting light energy into chemical energy, acting as a source for the growth of the leafy head. In the leafy head, the outer heading leaves expose their abaxial side to the light while the inner leaves are shielded from the light and have become a sink organ of the growing Chinese cabbage plant. Interestingly, variation in several ad/abaxial polarity genes is associated with the typical leafy head morphotype. The initiation of leaf primordia and the establishment of leaf ad/abaxial polarity are essential steps in the initiation of marginal meristem activity leading to leaf formation. Understanding the molecular genetic mechanisms of leaf primordia formation, polar differentiation, and leaf expansion is thus relevant to understand leafy head formation. As Brassica's are mesa-hexaploids, many genes have multiple paralogues, complicating analysis of the genetic regulation of leaf development. In this study, we used laser dissection of Chinese cabbage leaf primordia and the shoot apical meristem (SAM) to compare gene expression profiles between both adaxial and abaxial sides and the SAM aiming to capture transcriptome changes underlying leaf primordia development. We highlight genes with roles in hormone pathways and transcription factors. We also assessed gene expression gradients along expanded leaf blades from the same plants to analyze regulatory links between SAM, leaf primordia and the expanding rosette leaf. The catalogue of differentially expressed genes provides insights in gene expression patterns involved in leaf development and form a starting point to unravel leafy head formation.

Morphological Analyses and QTL Mapping of Mottled Leaf in Zucchini (Cucurbita pepo L.).

The mottled leaf is one of the agronomic traits of zucchini and can be applied as a marker trait in aggregation breeding. However, the genetic mechanism responsible for mottled leaf has yet to be elucidated. In the present study, we used two inbred lines (line '19': silver mottled leaf; line '113': normal leaf) as parents for the physiological and genetic analysis of mottled leaf. The synthesis and net photosynthetic rate of chlorophyll were not significantly affected in the mottled areas of leaves. However, we detected a large space between the palisade parenchyma in the leaf mottle area of line '19', which may have caused the mottled leaf phenotype. Light also plays an important role in the formation of mottled leaf, and receiving light during the early stages of leaf development is a necessary factor. Genetic analysis has previously demonstrated that mottled leaf is a quantitative trait that is controlled by multiple genes. Based on the strategy of quantitative trait locus sequencing (QTL-seq), two QTLs were identified on chromosomes 1 and 17, named CpML1.1 and CpML17.1, respectively. Two major loci were identified using R/qtl software version 1.66 under greenhouse conditions in April 2019 (2019A) and April 2020 (2020A) and under open cultivation conditions in May 2020 (2020M). The major QTL, CpML1.1, was located in a 925.2-kb interval on chromosome 1 and explained 10.51%-24.15% of the phenotypic variation. The CpML17.1 was located in a 719.7-kb interval on chromosome 17 and explained 16.25%-38.68% of the phenotypic variation. Based on gene annotation, gene sequence alignment, and qRT-PCR analysis, the Cp4.1LG01g23790 at the CpML1.1 locus encoding a protein of the TPX2 family (target protein of Xklp2) may be a candidate gene for mottled leaf in zucchini. Our findings may provide a theoretical basis for the formation of mottled leaf and provide a foundation for the fine mapping of genes associated with mottled leaf. Molecular markers closely linked to mottled leaf can be used in molecular-assisted selection for the zucchini mottled leaf breeding.

Pressure induced transformation of biomass to a highly durable, low friction film on steel

Herein the authors report a detailed insight into the tribological and chemical mechanisms that take place when leaf matter is present at the wheel/rail interface. The approach used enables further insight into the formation and subsequent effects on friction from leaf derived layers. Results shed insight on the process that facilitates the formation of leaf derived layers, their structure and chemical make-up. Our analysis indicates that polyphenols, a chemical family that include tannins, have an important role in layer formation and hypothesis on the layer's stability, when formed under high pressures. The data indicate that the high pressure found at the wheel/rail interface facilitates conversion of biomass into a tenacious, thin film. This is shown by the increase in the amount of phenolic compounds present. Phenolic compounds are typically rich in oxygen functional groups that have the ability to bind to metal ions. This insight into the composition of the film is expected to enable the development of novel remediation strategies. It highlights the potential for cleaning agents to be used as tools for restoring friction to safe values. This should lead to improvements in the operational performance and safety of rail transport for passengers and train operators.

The influence of biological preparations and micronutrients on the productivity of winter wheat

The research was carried out in order to evaluate the effectiveness of the use of biological preparations and micronutrients both separately and when used together to form the quality of winter wheat grain in the conditions of unstable humidification zone of the Stavropol Territory. The work was carried out in 2020-2022 in the fields of the experimental station of the Stavropol State Agrarian University on leached chernozem. The experience is two-factor, the repetition is three-fold. The experience scheme includes 10 options. As a control, an economic option was adopted (the technology of winter wheat cultivation recommended by scientific institutions of the region). In the experiment, biological preparations and micronutrients were studied both independently and with their joint use (factor A). The studied biological preparations and micronutrients were used during seed pickling and on vegetating plants during spring tillering and the formation of a flag leaf (factor B). The applied preparations, when used together, provide an increase in yield by 0.53 t / ha, forming a grain of the fourth class.