Inflorescence Stem Research Articles

QUANTITATIVE PARAMETERS OF FLORAL STEMS OF GLADIOLUS PLANTS GROWN UNDER MINIMUM TILLAGE SYSTEM IN SANTA CATARINA, BRAZIL

ABSTRACT The objective of this work was to characterize the commercial quantitative standards of floral stems of gladiolus plants grown under minimum tillage and conventional systems in two harvest seasons in the state of Santa Catarina, Brazil. Experiments were conducted in locations with subtropical climate using soils classified as Typic Dystrudept (Cambissolo) and Typic Hapludox (Nitossolo). Gladiolus plants were grown in beds with intensive soil turning, and under minimum tillage system, in which soil turning was done only in the planting rows. Plants of the cultivars Red Beauty and White Goddess were evaluated in two harvest seasons, Mothers' Day, and Valentine's Day. A completely randomized experimental design with 12 replications was used; the treatments consisted of two harvest seasons and two soil management systems. The flower stem and inflorescence lengths, stem thickness, and number of florets were measured when the plants were at the harvest point to characterize their commercial quantitative standards. These data were used to distribute the stems into four classes (75, 90, 110 and non-marketable). The stem standard of gladiolus plants grown under minimum tillage system and the edaphoclimatic conditions of the state of Santa Catarina in the Mother's Day harvest met the flower market requirements, with most stems classified into the classes 90 and 110. Therefore, gladiolus plants can be grown under minimum tillage system without affecting the flower stem development. This work is the first step to promote the growth of flowers under a conservationist perspective, focused on a more sustainable agriculture.

Tomato (Solanum lycopersicum) growth and fruit quality affected by organic fertilization and ozonated water.

The use of modern and safe techniques to increase plant growth and yield is of significance. There is little data, to our knowledge, on the use of organic fertilization and ozonated water (ozone (O3) affecting tomato (Solanum lycopersicum) growth and quality. Different tomato growth and fruit quality parameters including yield, fruit number, leaf fresh and dry weight, leaf and inflorescence number, plant height and stem diameter, distance from the first inflorescence to the collar, total soluble solids, total acidity, chlorophyll a, chlorophyll b, and total were determined. O3 treatment resulted in significant affects in all tomato parameters. One of the interesting results of the present research is the increased concentration ofthe antioxidant ascorbic acid (vitamin C) in response to ozonation, which can also improve tomato quality. However, organic fertilization and its interaction with the O3 treatment significantly affected only some of the measured tomato parameters. Ozonated water, at proper concentrations, may improve tomato growth and fruit quality, and if combined with organic fertilization, its positive effects may increase.

Nitric Oxide Alters the Pattern of Auxin Maxima and PIN-FORMED1 During Shoot Development.

Hormone patterns tailor cell fate decisions during plant organ formation. Among them, auxins and cytokinins are critical phytohormones during early development. Nitric oxide (NO) modulates root architecture by the control of auxin spatial patterns. However, NO involvement during the coordination of shoot organogenesis remains unclear. Here, we explore the effect of NO during shoot development by using a phenotypic, cellular, and genetic analysis in Arabidopsis thaliana and get new insights into the characterization of NO-mediated leaf-related phenotypes. NO homeostasis mutants are impaired in several shoot architectural parameters, including phyllotactic patterns, inflorescence stem elongation, silique production, leaf number, and margin. Auxin distribution is a key feature for tissue differentiation and need to be controlled at different levels (i.e., synthesis, transport, and degradation mechanisms). The phenotypes resulting from the introduction of the cue1 mutation in the axr1 auxin resistant and pin1 backgrounds exacerbate the relationship between NO and auxins. Using the auxin reporter DR5:GUS, we observed an increase in auxin maxima under NO-deficient mutant backgrounds and NO scavenging, pointing to NO-ASSOCIATED 1 (NOA1) as the main player related to NO production in this process. Furthermore, polar auxin transport is mainly regulated by PIN-FORMED 1 (PIN1), which controls the flow along leaf margin and venations. Analysis of PIN1 protein levels shows that NO controls its accumulation during leaf development, impacting the auxin mediated mechanism of leaf building. With these findings, we also provide evidence for the NO opposite effects to determine root and shoot architecture, in terms of PIN1 accumulation under NO overproduction.

Ectopic expression of GhIQD14 (cotton IQ67 domain-containing protein 14) causes twisted organ and modulates secondary wall formation in Arabidopsis

In plants, although KNOX genes are known to regulate secondary cell wall (SCW) formation, their protein-regulating mechanisms remain largely unknown. Here, we showed that GhKNL1, which regulates SCW formation and fiber development in cotton, could interact with an IQ67 domain containing protein (GhIQD14) in yeast. Confocal observation showed that GhIQD14 was localized to the microtubules. In Arabidopsis, ectopic expression of GhIQD14 caused hypocotyls to be sensitive to microtubule depolymerization agent, organ twisting of seedlings, trichomes, rosette leaves, and capsules, as well as severely irregular xylem vessels and thicker interfascicular fiber cell walls in the inflorescence stem. Furthermore, we found that GhIQD14 interacted with AtKNAT7 in vivo, and instantaneous co-expression of GhIQD14 and AtKNAT7 in tobacco showed that GhIQD14 weakened the distribution of AtKNAT7 in the nucleus, bringing it into the microtubules, thus affecting the SCW formation related genes expression. Our results suggested that GhIQD14 might be involved in the morphological development and SCW formation in cotton.

Arabidopsis SMAX1 overaccumulation suppresses rosette shoot branching and promotes leaf and petiole elongation

ArabidopsisSMAX1/SMXL (SUPPRESSOR OF MAX2 1/SMAX1-LIKE) proteins function as transcriptional repressors in karrikin and strigolactone (SL) signaling pathways and regulate plant architecture. MAX2 is a common factor in the two signaling pathways and a component of the SCF complex that modulates the proteasome-mediated degradation of SMAX1/SMXLs. SMXL6, 7, and 8 proteins promote shoot branching and inhibit petiole elongation. Our study found that the accumulation of SMAX1 suppresses rosette shoot branching and increases cauline branches on the primary inflorescence stem, plant height, petiole length, and leaf length/width ratio. The SMAX1 accumulation enhances the expression of BRC1, HB53, HB40, and HB21 that modulate shoot branching. SMAX1 also regulates the expression of the genes involved in auxin transport, cytokinin signaling pathway, and SL biosynthesis. The expression analyses of these genes suggest that excessive SMAX1 should accelerate the transport of auxin and the biosynthesis of SL in plants. High SL concentration suppresses the bud development in smax1D mutant that accumulates SMAX1 protein in plant. However, the effects of cytokinin and auxin on shoot branching remain elusive in the mutant with excessive SMAX1. SMAX1 regulates leaf shape and petiole length via modulating TCP1 expression. Our findings reveal a novel function of SMAX1 and new mechanism of shoot branching.

Allometric equations for liana species Derris trifoliata and the relationship between inflorescence generation and stem diameter

The liana species Derris trifoliata is an associate species in mangroves, but in recent years, its biomass and abundance have increased. The biomass estimated for Derris trifoliata is vital for determining the carbon stores in mangrove habitats. And the allometric equations are insufficient but essential for lianas. We collected 132 samples of D. trifoliata to produce a regression analysis, following which allometric equations of biomass (root, stem, leaf, ground, and total biomass) were obtained. The allometric equations we obtained based on basal diameter have a better effect to predict stem biomass, ground biomass, and total biomass, and the adjusted R2 for these measures was 0.5258, 0.5287, and 0.5397, respectively. When leaf biomass was simultaneously added as another independent variable, the accuracy of the prediction of the total biomass (adjusted R2 = 0.6715) and stem biomass (adjusted R2 = 0.6163) improved. The ratio of root biomass to total biomass, stem biomass to total biomass, and leaf biomass to total biomass was 0.208–0.430, 0.394 to 0.643, and 0.146 to 0.199, respectively. The biomass accumulation increased with the increase of basal diameter and the ratio of root biomass to ground biomass decreased with the increase of basal diameter, which is likely due to the limited light resources. We measured the stem diameter where the raceme was located and a total of 304 raceme or fruit spur samples were selected. Finally, we found that the number of raceme or fruit spur increased first and then decreased with the increase of stem diameter. The stem diameter, to some extent, represents the age class of the stem: thinner stems have a greater chance of sexual reproduction than thicker stems. The models provided in this paper will facilitate the estimation of the productivity of forests and the amount of carbon sequestered by forests, and the relationship between the generation of inflorescences and stem diameter can predict sexual reproduction and diffusion in the present D. trifoliata distribution area.

Chemical analysis and bioactivity evaluation of the stem of Rheum tanguticum

Rhubarb (Dahuang in Chinese), belongs to the family Polygonaceae, genus Rheum, has been employed as a traditional Chinese medicinal material for a long time. Rheum officinale, R. palmatum, R. tanguticum, R. rhaponticum, R. ribes, R. franzenbachii, and R. rhabarbarum have been reported to possess many pharmacological active substances that are used to treat diseases. The petioles of R. rhabarbarum, R. ribes, R. rhaponticum are well-known vegetables in some regions of the world. Based on this folk application and active ingredients that may be present in stems, the present study was conducted to analyze the content of nutritional components and active secondary metabolism components, and evaluate the antimicrobial activity and antioxidant activity with prepared solvent extracts. Methods published by the Association of Official Analytical Chemistry (AOAC) was used to determine the total protein, crude fat, crude fiber, vitamin C, ash, and moisture contents. The results showed that the inflorescence stem of R. tanguticum contained a higher content of crude fiber (89.14%) and vitamin C (16.96%). The content of total protein and crude fat was 8.49% and 1.34% respectively. The results showed that the DPPH Radical Scavenging Activity of the extract had a concentration-dependent effect. The highest activity (83.4%) of the methanol extract sample was recorded at 1.0 mg/mL and the lowest activity, 15.56%, was recorded at 0.2 mg/mL. 0.485 mg/mL was needed to achieve a 50% toxicity. The flavonoid and total phenolic contents of the inflorescence stem of R. tanguticum were found to be 0.022 mg/g and 4.138 mg/g respectively. A concentration of 10 mg/mL successfully inhibited the growth of the pathogenic microorganisms, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis using the paper disc diffusion method. In summary, the results of this study confirm that the inflorescence stem of R. tanguticum contains some rich nutritional components and bioactive secondary metabolism components that are beneficial for human health as edible parts or processed products. The results of bioactivity evaluation in this study also showed that the inflorescence stem of R. tanguticum could be developed natural antioxidant and antibacterial agent as a potential resource. This may possibly provide a feasible solution for non-medicinal parts utilization.

Developmental plasticity in Arabidopsis thaliana under combined cold and water deficit stresses during flowering stage.

Morpho-physiological changes were observed in Arabidopsis plants acclimated to long-term combined cold and water deficit stresses. Limiting growth and differences in bolting, flowering, and silique development were evidenced. In nature, plants are exposed to multiple and simultaneous abiotic stresses that influence their growth, development, and reproduction. In the last years, the study of combined stresses has aroused the interest to know the physiological and molecular responses, because these new stress conditions are probed to be different from the sum of the individual stress. We are interested in the study of the acclimation of plants growing under the combination of cold and water deficit stresses prevalent in cold-arid or semi-arid climates worldwide. We hypothesized that the reproduction of the acclimated plants will be compromised and affected. Arabidopsis plants were submitted to long-term combined stress from the beginning to the reproductive stage, when floral bud was visible, until the silique development. Our results demonstrate severe morpho-anatomical changes after acclimation to combined stress. Inflorescence stem morphology was altered having a delayed bolting and a limited growth. Flowering and silique formation were delayed, and a higher size in the corolla and the petals was observed. Flower and silique number were severely diminished as a result of combined stress, unlike acclimated plants to individual cold stress. These traits were recovered after deacclimation to optimal conditions and plants achieved similar silique production as control plants. The long-term stress results suggest that there is not a single dominant stress, but there is an alternating dominance depending on the structure or the plant stage development evaluated.

Metabolome profiling and molecular docking analysis revealed the metabolic differences and potential pharmacological mechanisms of the inflorescence and succulent stem of Cistanche deserticola.

Cistanche deserticola is an endangered plant used for medicine and food. Our purpose is to explore the differences in metabolism between inflorescences in non-medicinal parts and succulent stems in medicinal parts in order to strengthen the application and development of the non-medicinal parts of C. deserticola. We performed metabolomics analysis through LC-ESI-MS/MS on the inflorescences and succulent stems of three ecotypes (saline-alkali land, grassland and sandy land) of C. deserticola. A total of 391 common metabolites in six groups were identified, of which isorhamnetin O-hexoside (inflorescence) and rosinidin O-hexoside (succulent stems) can be used as chemical markers to distinguish succulent stems and inflorescences. Comparing the metabolic differences of three ecotypes, we found that most of the different metabolites related to salt-alkali stress were flavonoids. In particular, we mapped the biosynthetic pathway of phenylethanoid glycosides (PhGs) and showed the metabolic differences in the six groups. To better understand the pharmacodynamic mechanisms and targets of C. deserticola, we screened 88 chemical components and 15 potential disease targets through molecular docking. The active ingredients of C. deserticola have a remarkable docking effect on the targets of aging diseases such as osteoporosis, vascular disease and atherosclerosis. To explore the use value of inflorescence, we analyzed the molecular docking of the unique flavonoid metabolites in inflorescence with inflammation targets. The results showed that chrysoeriol and cynaroside had higher scores for inflammation targets. This study provides a scientific basis for the discovery and industrialization of the resource value of the non-medicinal parts of C. deserticola, and the realization of the sustainable development of C. deserticola. It also provides a novel strategy for exploring indications of Chinese herb.

A systematic study on the chemical diversity and efficacy of the inflorescence and succulent stem of Cynomorium songaricum.

Cynomorium songaricum is a medicinal, edible, and endangered plant species. Since inflorescences are not considered medicinal parts, their discard causes a waste of resources. To expand the medicinal uses of C. songaricum, we evaluated their chemistry and pharmacology by applying widely targeted metabolomics, network pharmacology, and molecular docking. Widely targeted metabolomics results indicated chemical diversity in C. songaricum with 599 compounds. Among them, 280 compounds were different between the succulent stem and inflorescence. With 218 upregulated compounds, inflorescence has more abundant compounds than the succulent stem, especially pigment compounds such as flavonols, flavones, and flavanones. Moreover, anthocyanin and proanthocyanidin were unique compounds in the inflorescence and succulent stem, respectively. Sixty-five compounds in inflorescence and 18 compounds in succulent stems were found to be associated with atherosclerosis in the network pharmacology analysis. Tests revealed that inflorescence had a stronger anti-atherosclerotic effect than succulent stems. Molecular docking analysis revealed that 30 compounds (29 pigment compounds) in inflorescence and 6 compounds (4 pigment compounds) in succulent stem showed strong binding affinities with three target proteins, namely ALB, MPO, and NOS2, especially amentoflavone, quercetin 7-O-rutinoside, and luteolin 7-O-glucoside (cynaroside). Results demonstrated that the inflorescence is rich in pigment compounds and has a potential anti-atherosclerosis effect. This study provides novel methods and ideas for the sustainable development of endangered medicinal plants.

EFFECT OF BULB SIZE AND BA ON GROWTH, FLOWERING, BULBS PRODUCTIVITY AND CHEMICAL COMPOSITION OF Hippeastrum vittatum PLANT

Two field experiments were conducted to evaluate the influence of 12 treatments represented the combination between thee bulb sizes of Hippeastrum vittatum (small, medium, and large.) and four concentration of BA (0, 20, 40 and 60 ppm) on the growth, flowering, bulbs productivity and chemical composition of Hippeastrum vittatum plant. Results showed that the combined treatment between large bulb size and BA at 60 ppm significantly gave the tallest plant, highest number of leaves / plant and the heaviest fresh and dry weights of leave/plant, followed by the combined treatment between large bulb size and BA at 40 ppm in the two seasons. The earliest flowering, the highest values of inflorescence length, inflorescence stem diameter, inflorescence fresh weight and flowering percentage were recorded by the combined treatment between large bulb size and BA at 60 ppm in the two seasons. The heaviest bulb fresh and dry weights, the highest bulbs number/plant and the thickest bulb and bulblet were scored by the combined treatment between the large bulb and BA at 60 ppm in the two seasons. The highest leaf N, P, K, total carbohydrates and total chlorophylls contents were scored by the combination of large bulb size, especially, those received BA at 60 ppm in the two seasons. Conclusively, spraying Hippeastrum vittatum plants with BA at 60 ppm induced prospective effects on vegetative growth and flowering parameters with higher bulbs productivity.

EFFECT OF BULB SIZE AND CHEMICAL FERTILIZATION ON GROWTH, FLOWERING, BULBS PRODUCTIVITY AND CHEMICAL COMPOSITION OF Hippeastrum vittatum PLANT

Two field trials were carried out to study the effect of 12 treatments represented the combination between thee bulb sizes of Hippeastrum vittatum (small, medium, and large.) and four rates of NPK chemical composition (0, 2, 4 and 6 g/plant) on the growth, flowering, bulbs productivity and chemical composition of Hippeastrum vittatum plant. Results showed that the combination of the large bulb size significantly induced the greatest values of plant height, leaves number and fresh and dry weights, particularly those treated with chemical fertilizer at the highest rate in the two seasons. The earliest flowering was recorded by the combined treatment between large bulb size and chemical fertilizer at 6g/L, followed by the combined treatment between large size and chemical fertilization at 4g/plant in the two seasons. Furthermore, the combination of large bulb size scored the highest values of inflorescence length, inflorescence stem diameter, inflorescence fresh weight and flowering percentage, especially those received chemical fertilization at the high rate in the two seasons. The highest results of bulb and bulblet diameter, bulb fresh and dry weights and number of bulblets / plant were detected with the combinations of large bulb size, especially those received chemical fertilization at the high rate in the two seasons. The highest leaf N, P, K. total carbohydrates and total chlorophylls contents were scored by the combined treatment between large bulb size and chemical fertilization at 6 g/plant in the two seasons. Conclusively, fertilizing Hippeastrum vittatum plants with mineral fertilization with N: P: K at 6g/L induced prospective effects on vegetative growth and flowering parameters with higher bulbs productivity.

Estimating the flexural rigidity of Arabidopsis inflorescence stems: Free-vibration test vs. three-point bending test.

The mechanical strength of a plant stem (a load-bearing organ) helps the plant resist drooping, buckling and fracturing. We previously proposed a method for quickly evaluating the stiffness of an inflorescence stem in the model plant Arabidopsis thaliana based on measuring its natural frequency in a free-vibration test. However, the relationship between the stiffness and flexural rigidity of inflorescence stems was unclear. Here, we compared our previously described free-vibration test with the three-point bending test, the most popular method for calculating the flexural rigidity of A. thaliana stems, and examined the extent to which the results were correlated. Finally, to expand the application range, we present an example of a modified free-vibration test. Our results provide a reference for improving estimates of the flexural rigidity of A. thaliana inflorescence stems.

Spatio-temporal kinematic analysis of shoot gravitropism in Arabidopsis thaliana.

Plant shoots can bend upward against gravity, a behavior known as shoot gravitropism. The conventional quantification of shoot bending has been restricted to measurements of shoot tip angle, which cannot fully describe the spatio-temporal bending process. Recently, however, advanced imaging analyses have been developed to quantify in detail the spatio-temporal changes in inclination angle and curvature of the shoot. We used one such method (KymoRod) to analyze the gravitropism of the Arabidopsis thaliana inflorescence stem, and successfully extracted characteristics that capture when and where bending occurs. Furthermore, we implemented an elastic spring theoretical model and successfully determined best fitted parameters that may explain typical bending behaviors of the inflorescence stem. Overall, we propose a data-model combined framework to quantitatively investigate shoot gravitropism in plants.

Histone methyltransferase ATX1 dynamically regulates fiber secondary cell wall biosynthesis in Arabidopsis inflorescence stem.

Secondary wall thickening in the sclerenchyma cells is strictly controlled by a complex network of transcription factors in vascular plants. However, little is known about the epigenetic mechanism regulating secondary wall biosynthesis. In this study, we identified that ARABIDOPSIS HOMOLOG of TRITHORAX1 (ATX1), a H3K4-histone methyltransferase, mediates the regulation of fiber cell wall development in inflorescence stems of Arabidopsis thaliana. Genome-wide analysis revealed that the up-regulation of genes involved in secondary wall formation during stem development is largely coordinated by increasing level of H3K4 tri-methylation. Among all histone methyltransferases for H3K4me3 in Arabidopsis, ATX1 is markedly increased during the inflorescence stem development and loss-of-function mutant atx1 was impaired in secondary wall thickening in interfascicular fibers. Genetic analysis showed that ATX1 positively regulates secondary wall deposition through activating the expression of secondary wall NAC master switch genes, SECONDARY WALL-ASSOCIATED NAC DOMAIN PROTEIN1 (SND1) and NAC SECONDARY WALL THICKENING PROMOTING FACTOR1 (NST1). We further identified that ATX1 directly binds the loci of SND1 and NST1, and activates their expression by increasing H3K4me3 levels at these loci. Taken together, our results reveal that ATX1 plays a key role in the regulation of secondary wall biosynthesis in interfascicular fibers during inflorescence stem development of Arabidopsis.

Tissue-specific transcriptome profiling of the Arabidopsis inflorescence stem reveals local cellular signatures.

Genome-wide gene expression maps with a high spatial resolution have substantially accelerated plant molecular science. However, the number of characterized tissues and growth stages is still small due to the limited accessibility of most tissues for protoplast isolation. Here, we provide gene expression profiles of the mature inflorescence stem of Arabidopsis thaliana covering a comprehensive set of distinct tissues. By combining fluorescence-activated nucleus sorting and laser-capture microdissection with next-generation RNA sequencing, we characterized the transcriptomes of xylem vessels, fibers, the proximal and distal cambium, phloem, phloem cap, pith, starch sheath, and epidermis cells. Our analyses classified more than 15,000 genes as being differentially expressed among different stem tissues and revealed known and novel tissue-specific cellular signatures. By determining overrepresented transcription factor binding regions in the promoters of differentially expressed genes, we identified candidate tissue-specific transcriptional regulators. Our datasets predict the expression profiles of an exceptional number of genes and allow hypotheses to be generated about the spatial organization of physiological processes. Moreover, we demonstrate that information about gene expression in a broad range of mature plant tissues can be established at high spatial resolution by nuclear mRNA profiling. Tissue-specific gene expression values can be accessed online at https://arabidopsis-stem.cos.uni-heidelberg.de/.

Early Mass Selection Response of Two Quinoa Landraces under Highlands Conditions in Northern Chile

Quinoa has been cultivated since centuries in the Andean region as a seed crop by indigenous communities. The crop has gained renewed interest because of its highly nutritious grain with high-quality protein rich in essential amino acids, and several bioactive compounds, along with its ability to grow under stress conditions. Despite the importance of the crop, limited research work on breeding aspects has been undertaken, leading to lack of information on the understanding of levels of variability of genotypes for different traits and their interactions. The aim of the present study was to assess and quantify the early response to mass selection in two quinoa landraces in highland conditions. Mass selection experiments were conducted during two successive crop seasons using eleven morphological traits. Correlation, genetic gain (gg) per selection cycle and principal component analysis was carried out. Only plant height (PH) and number of branches (NB) presented changes between selection cycles in both germplasm lines. Grain yield per plant (GYP) was positively correlated with inflorescence length (IL), stem diameter (SD) and plant weight (PW) for both quinoa lines. The results obtained would be useful to facilitate selection of the most relevant variables of quinoa considering its variation and interactions in the highland environment in Chile.

Transcription of the WUSCHEL-RELATED HOMEOBOX 4 gene in Arabidopsis thaliana

Phylogenetic shadowing and chromatin accessibility data suggested that essential regulatory elements are absent in the 2.9 kb immediate upstream region of the published WOX4pro::YFP cambium marker. Inclusion of an additional 6.3 kb of upstream promoter sequence and confocal imaging with different fluorophores in transgenic Arabidopsis lines revealed a much wider cell-type-specific expression pattern in parenchymous cells of the aerial plant body. The previously demonstrated activity of the WOX4pro::YFP marker in the cambium of vascular strands in the young Arabidopsis inflorescence stem depicts only sectors of a circular subcortical layer of parenchymous AtWOX4-positive cells. Transcription starts in subepidermal cells within the inflorescence apex in a phyllotactic pattern and extends into successively branching lateral organs, which are connected via small tube-like domains of AtWOX4-expressing cells with the circular subcortical parenchymal layer that extends basipetally down the stem. AtWOX4 expression is most dynamic in leaves, where promoter activity is observed transiently at the adaxial side of the lamina and remains detectable later in the palisade parenchyma, although at a weaker level than in the vasculature. In the root the extended AtWOX4 promoter is active through the proximal root meristem, i.e. in the quiescent centre (QC) and its surrounding initials, a pattern that is broader than transcription of its stem cell promoting relative AtWOX5 in the QC. Outside the proximal meristem AtWOX4 transcription is observed in upper cell layers of the columella root cap beneath or above within the stele in proto- and metaxylem cells, in a ribbon-type pattern which divides the central cylinder in two equal halves. This xylem-specific expression it the root stele relates to established AtWOX4 activity in xylem parenchyma specificity within vascular bundles of the stem.

Distinct phenolic, alkaloid and antioxidant profile in betel quids from four regions of Indonesia

Betel quid (BQ) is a chewing mixed package that mainly contains areca nut (AN), betel leaf (Leaf) or betel stem inflorescence (SI), and slaked lime, and is consumed with or without tobacco BQ chewing is common in South East Asia and has been strongly associated with malignant and potentially malignant diseases of the oral cavity. Alkaloids such as arecoline are often accounted for the carcinogenic potential of BQ, however the chemical composition of BQ has not been studied in detail. In the current study, we investigated the total phenolic content (TPC), antioxidant activity (by mean of ferric reducing antioxidant power, FRAP), radical scavenging activity (DPPH test), polyphenolic profile and arecoline content in different components of BQ, namely AN, Leaf or SI, Husk, and blended BQ (BQ mix, containing AN, Leaf or SI and slaked lime). Samples were imported from 4 major regions of Indonesia, namely: Banda Aceh (BA), North Sumatra (NS), West Kalimantan (WK) and West Papua (WP). The highest TPC, FRAP, and DPPH values were detected in AN samples compared to other BQ components, while samples from WP region were of higher values compared to the other regions. High performance liquid chromatography—Mass Spectrometry (LC–MS) analysis showed that Husk contains the widest range of polyphenols, including hydroxybenzoic acids, hydroxycinnamic acids, flavanols, flavonols and stilbenes. Catechin and epicatechin were the main polyphenols detected in BQ, and they were present at the highest concentrations in WP–AN sample. Arecoline was detected in all AN and BQ mix samples and was significantly correlated with catechin and epicatechin, and significantly negatively correlated with p-hydroxybenzoic acid. Notably, arecoline concentration changed significantly when AN was blended in BQ mixtures. The current study is the first to extensively characterise the chemical composition of BQ and provides insight for a better understanding of the interactions of BQ alkaloids and phenolics in the development of oral submucous fibrosis and oral cancer.

A new perspective on mechanical characterisation of Arabidopsis stems through vibration tests

The mechanical properties of plants are important for understanding plant biomechanics and for breeding new plants that can survive in challenging environments. Thus, accurate and reliable methods are required for the determination of mechanical properties such as stiffness and Young's modulus of elasticity. Much attention has been paid to the application of static methods to plants, while dynamic methods have received considerably less attention. In the present study, a dynamic forced vibration method for mechanical characterisation of Arabidopsis inflorescence stems was developed and validated against the conventional three-point bending test. Compared to dynamic tests based on free vibration, the current method allows to determine simultaneously more than one natural frequency, thus increasing the overall accuracy of the results. In addition, this method can be applied to the top parts of the stems that are more flexible, and where application of the three-point bending test is often limited. To demonstrate one of the potential applications of this method, it was applied to evaluate the influence of turgor pressure on the mechanical properties of Arabidopsis stems. Overall, the new dynamic testing approach has been shown to provide reliable data for the local mechanical properties along the Arabidopsis inflorescence stem.