Stem Sections Research Articles

Micropropagation of arrow cane, Gynerium sagittatum (Aubl.) P. Beauv. cv. Criolla, Criolla 1, and Martinera, in a double-phase medium

To evaluate the micropropagation response of arrow cane, Gynerium sagittatum (Aubl.), plants using a double-phase medium in the multiplication stage, explants consisting of stem sections with axillary meristems from cultivars Criolla, Criolla 1, and Martinera were established in vitro in a semisolid medium. Then, they were multiplied using a double-phase medium supplied at several Benzylaminopurine (BAP) concentrations (0.0, 0.5, 1.0, 1.5, and 2.0 mg/L), followed by rooting in a culture medium supplied at several Naphthaleneacetic acid (NAA) concentrations (0.0, 0.5, 1.0, 1.5, and 20 mg/L). Both multiplied unrooted and rooted microshoots were transferred ex vitro. Treatments were distributed with a completely randomized design; data were analyzed with an ANOVA and means separated with Tukey’s test. Explants from Criolla and Martinera cultured with 0.5 mg/L BAP resulted in higher multiplication rates. All microshoots transferred to the rooting medium rooted, although NAA significantly increased the number of roots and reduced root length. Plants from all three cultivars, in vitro rooted or unrooted transferred to ex vitro conditions, showed 100 % survival and adaptation. For Criolla and Martinera, 0.5 mg/L BAP statistically increased shoot multiplication rates and NAA increased adventitious root formation and reduced root length. Plants of all cultivars survived and adapted 100 % to ex vitro conditions.

Effect of necrotrophic fungus and PGPR on the comparative histochemistry of Vigna radiata by using multiple microscopic techniques.

Rapid advances in the field of pathogen detection have opened new opportunities and better understanding for their management approaches. Aim of this study was to elucidate histopathological observations of different tissues affected by Macrophomina phaseolina and to observe the defense responses of plant growth promoting rhizobacteria (PGPR) in mungbean plants. Sections of the stem and root were prepared and stained with ferric chloride, Lugol's iodine and Wiesner's reagent and were then observed under multiple microscopic techniques. Results revealed that both pathogen and PGPR produce responses on the plant that include colonization of xylem vessels by hyphae and sclerotia, hypertrophy and hyperplasia of the cells, destruction of xylem fibers and amyloplasts in parenchymatous cells; and production of gels by the plant were observed. There was a significant increase in lignin and phenolic compounds deposition in stem and root sections of PGPR treated and non-treated mungbean plants. Whereas the soil amended with PGPR showed very less to no starch production. Moreover, production of gels and gums were also observed in both stem and root sections. Compared to light microscopy, scanning electron microscope provided greater depth of focus and resolution of the pathogen attack on plant tissues, associated bacteria. As a whole, the data demonstrated that inoculation of PGPR can be an effective strategy to stimulate plant growth and they could significantly activate disease resistance against M. phaseolina.

Disease severity and ecophysiology of rootstock/scion combinations of different avocado (Persea americana Mill.) genotypes in response to laurel wilt

Laurel wilt, caused by the fungus Raffaelea lauricola, is a lethal vascular disease that affects many members of the Lauraceae family, including avocado (Persea americana Mill.) trees. Previous studies have shown differences in laurel wilt susceptibility among genotypes, with cultivars of the West Indian (WI) race generally more susceptible to laurel wilt than Guatemalan (G) or Mexican (M) race cultivars. We conducted four experiments to compare susceptibility and ecophysiological responses to laurel wilt among scion/rootstock combinations from the different botanical races. In the first two experiments, clonally propagated ‘Simmonds’ (WI) scion grafted on ‘Waldin’ (WI), ‘Reed’ (G) or ‘Duke 7’ (M) rootstock (Experiment 1), or grafted on ‘Waldin’, ‘Nabal’ (G) or ‘Zutano’ (M) rootstock (Experiment 2) were compared. In the other two experiments, ‘Waldin’, ‘Reed’ or ‘Duke 7’ scion grafted on ‘Duke 7’ rootstock (Experiment 3), or ‘Reed’ rootstock (Experiment 4) were compared. For each scion/rootstock combination, trees were divided into two treatments: inoculated with R. lauricola, or 2) inoculated with deionized water as a control. Disease severity in all trees was determined daily using a rating scale based on the percentage of visible symptoms. Net CO2 assimilation (A), stomatal conductance of water vapor (gs), the daily xylem sap flow rate, and the ratio of variable to maximum chlorophyll fluorescence (Fv/Fm) in leaves were determined three times per week until one or more scion/rootstock combination in the laurel wilt treatment showed severe symptoms. Trees from each treatment were then harvested and stem sections observed for browning of the sapwood (a characteristic laurel wilt symptom), and plated on a selective medium to recover the fungus if present. Raffaelea lauricola was recovered in all trees in the laurel wilt treatment and no trees in the control treatment. Laurel wilt susceptibility varied among the scion/rootstock combinations. Trees in the laurel wilt treatment with ‘Simmonds’ as the scion developed more symptoms and exhibited a greater reduction in physiological variables than the control trees, regardless of the genotype of the rootstock. ‘Duke 7’, either as the scion or rootstock, inoculated with the laurel wilt pathogen had less disease development and less of a reduction in physiological variables than the other genotypes. The results indicate that there are differences in laurel wilt susceptibility among grafted avocado cultivars of different genotypes. These difference may be related to the botanical race of the scion and/or the rootstock.

De novo hydroponics system efficiency for the cuttings of alfalfa (Medicago sativa L.)

The legume plant alfalfa (Medicago sativa L.) is a widely cultivated perennial forage due to its high protein content, palatability, and strong adaptability to diverse agro-ecological zones. Alfalfa is a self-incompatible cross-pollinated autotetraploid species with tetrasomic inheritance. Therefore, maintaining excellent traits through seed reproduction is a prime challenge in alfalfa. However, the cutting propagation technology could enable consistent multiplication of quality plants that are genetically identical to the parent plant. The current study aimed to develop a simple, cost-effective, reproducible, and efficient hydroponic cutting method to preserve alfalfa plants and for molecular research. In this study, alfalfa landrace ‘Wudi’ was grown in hydroponics for 30 days and used as source material for cuttings. The top, middle and bottom sections of its stem were used as cuttings. The rooting rate, root length, and stem height of the different stem sections were compared to determine the best segment for alfalfa propagation in four nutrient treatments (HM, HM + 1/500H, HM + 1/1000H and d HM + 1/2000H). After 21 days of culture, the rooting rates of all the three stem types under four cutting nutrient solutions were above 78%. The rooting rate of the middle and bottom parts in HM + 1/1000 H and HM + 1/2000 H nutrient solutions reached more than 93%, with a higher health survey score (> 4.70). In conclusion, this study developed a de novo cutting propagation method that can be used to conserve and propagate germplasm in breeding programs and research. This method is a new report on the cutting propagation of alfalfa by hydroponics, which could supplement the existing cutting propagation methods.

Improved chemical pulping and saccharification of a natural mulberry mutant deficient in cinnamyl alcohol dehydrogenase

Abstract Lignin content and its molecular structure influence various wood characteristics. In this study, the anatomical and physicochemical properties of wood derived from a naturally occurring mulberry mutant deficient in cinnamyl alcohol dehydrogenase (CAD), a key enzyme in lignin biosynthesis, were analyzed using conventional staining assays on stem sections, length and width measurements of xylem fiber cells, wood pulping and saccharification assays, and sugar compositional analysis of extractive-free wood powder. The present data indicate that the mutation in the CAD gene leads to improved wood delignification efficiency, increased pulp yield under alkaline pulping conditions, and enhanced saccharification efficiency following alkaline pretreatment. This study opens up new avenues for the multipurpose use of the mulberry CAD-deficient mutant as a raw material for biorefinery processes, in addition to its traditional use as a favored feed for silkworms.

Anatomical study of the Carissa macrocarpa (Apocynaceae family) in Iraq

This study was conducted to examine the anatomical aspects of Carissa macrocarpa, of stem, leaf and leaf venation. The results obtaind showed that the tissue of the studied parts have important anatomical characteristics in terms of the shape of the cross-sectional of stem and vertical-sectional of leaves. The stem section appeared in circular and the midrib was crescent shape and the stomata appeared on the upper surface of the leaf only, Tetracytic in type. Druses crystals and Aleurone granules appeared on both surfaces of leaves. The venation type was Brochidodromous in which the secondary veins do not end at the edge of the leaf, and each secondary race is connected with the higher race and linked together with a series of prominent arches.

Experimental characterisation and three-dimensional modelling of Elymus for the assessment of ecosystem services

To make a significant contribution to the fundamental understanding of how the internal tissue structure of the Elymus culm is related to the culm stiffness and flexibility with respect to its section height, the present work uses state-of-the-art methods such as three‐-/two-point bending experiments, histological investigations, and numerical optimisation/identification modelling. The combination of these methods generates a knowledge that is needed, to adequately model the degree of bending and associated drag forces in hydrodynamic models used to predict wave loads on landward lying coastal protection structures. In addition, it is possible to predict the likely plant culm stresses that will ultimately lead to plant breakage and removal, and thus to a temporary reduction in coastal protection. The results of this study show that knowledge of the geometric cross sectional information (cross sectional area and area moment of inertia) is indispensable for an adequate description of the mechanical behaviour of the grass culm. Especially the area moment of inertia was often overestimated in previous studies. It also becomes clear that the histological plant characteristics in the form of tissue compositions explain the differences in stiffness and thus in bending behaviour that exist between the different stem sections (bottom, middle, top). The methodology presented here, combining experimental investigations and numerical methods, has the potential to make a significant contribution to the elucidation of plant load transfer and wave-vegetation interaction in the future.

Transcriptomic Analysis of Seasonal Gene Expression and Regulation during Xylem Development in “Shanxin” Hybrid Poplar (Populus davidiana × Populus bolleana)

Xylem development is a key process for wood formation in woody plants. To study the molecular regulatory mechanisms related to xylem development in hybrid poplar P. davidiana × P. bolleana, transcriptome analyses were conducted on developing xylem at six different growth stages within a single growing season. Xylem development and differentially expressed genes in the six time points were selected for a regulatory analysis. Xylem development was observed in stem sections at different growth stages, which showed that xylem development extended from the middle of April to early August and included cell expansion and secondary cell wall biosynthesis. An RNA-seq analysis of six samples with three replicates was performed. After transcriptome assembly and annotation, the differentially expressed genes (DEGs) were identified, and a Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and expression analysis of the DEGs were performed on each sample. On average, we obtained >20 million clean reads per sample, which were assembled into 84,733 nonredundant transcripts, of which there were 17,603 unigenes with lengths >1 kb. There were 14,890 genes that were differentially expressed among the six stages. The upregulated DEGs were enriched in GO terms related to cell wall biosynthesis between S1 vs. S2 or S3 vs. S4 and, in GO terms, related to phytohormones in the S1 vs. S2 or S4 vs. S5 comparisons. The downregulated DEGs were enriched in GO terms related to cell wall biosynthesis between S4 vs. S5 or S5 vs. S6 and, in GO terms, related to hormones between S1 vs. S2 or S2 vs. S3. The KEGG pathways in the DEGs related to “phenylpropanoid biosynthesis”, “plant hormone signal transduction” and “starch and sucrose metabolism” were significantly enriched among the different stages. The DEGs related to cell expansion, polysaccharide metabolism and synthesis, lignin synthesis, transcription factors and hormones were identified. The identification of genes involved in the regulation of xylem development will increase our understanding of the molecular regulation of wood formation in trees and, also, offers potential targets for genetic manipulation to improve the properties of wood.

In vitro flowering and fruiting in Portulaca pilosa L.

In vitro flowering and fruiting of Portulaca pilosa L. were achieved for the first time. The ability of several factors to induce in vitro flowering, including plant growth regulators and carbon sources, were investigated. Initial in vitro flowering (12.1%) from stems, most likely from floral buds that had differentiated before stem sections were inoculated on MS medium supplemented with 30 g/L sucrose, 1.0 µM BA and 0.1 µM NAA, occurred within less than one month. Axillary shoots were subcultured multiple times on this medium. Secondary in vitro flowering (12.2%) and fruit setting from axillary shoots was possible on MS medium supplemented with 120 g/L sucrose without any plant growth regulators. Continuous culture on this medium for 12 days after flowering yielded fruits and produced a mean 58 normal seeds per fruit. Seeds germinated and developed seedlings in vitro without any additional treatment.

Quantitative trait loci for stem strength properties and lodging in two pea biparental mapping populations

AbstractLodging is the major factor that determines whether pea (Pisum sativum L.) can be mechanically harvested. The aim of this experiment was to investigate the relationship between stem mechanical parameters (diameter, stem wall thickness, stiffness [rigidity], and maximum self‐weight moment [stem strength]) and lodging in pea. Three years of data on stem mechanical parameters and 2 yr of data on lodging resistance were collected on the ‘Carneval’ × ‘MP1401’ pea cultivars and Wt10245 × Wt11238 lines. Mechanical parameters were measured separately for three stem sections: lower, middle, and upper. Nine quantitative trait loci (QTL) associated with stem mechanical parameters were identified in the Carneval × MP1401 genetic map. Eight QTL associated with stem mechanical parameters were identified in the Wt10245 × Wt11238 genetic map. These results confirmed QTL for lodging resistance found previously, especially in regards to located in chr5LG3 close to the A004 marker. Quantitative trait loci for stem diameter and stem strength of the upper and lower stem colocated with the Rfs marker in chr5LG3. A plant height QTL was detected close to AB141 marker, 2 cM (3.3 Mbp) from the Le gene. These results enable identification of pea genomic regions associated with agriculturally important traits and provide a foundation for further research to improve lodging resistance in pea.

Strategies for vegetative propagation and viral cleaning of a miniature ornamental pineapple hybrid

This study assessed and compared different methods for vegetative propagation of a miniature ornamental pineapple hybrid (ORN-MUT), seeking to determine the best method for production of plantlets, as well as for removal of the PMWaV viral complex from plants cultured in vitro, for production of healthy parent plants. Pineapple wilt is a disease that can cause large economic and is caused by a viral complex called Pineapple mealybug wilt-associated virus (PMWaV). For this, four propagation methods were evaluated (conventional, stem sectioning, micropropagation and etiolation of nodal segments). The time necessary for each method and the number of plants formed were assessed. Stem tips (0.5 mm) were cultured and indexed for three PMWaV types. Conventional propagation produced 17 plantlets per plant in 566 days, stem sectioning produced 2.3 plantlets per stem in 591 days, while the conventional micropropagation technique produced 1,284 plants after four subcultures in 778 days. Stems etiolated for 60 days showed peak production in the second subculture, with 1,224 plants. This method required 883 days to obtain plants with ideal size for transplantation to the field. In turn, stems etiolated for 120 days produced 935 plants at the end of four subcultures, with peak output in the third subculture, in which the plants could be cultivated in the field after 943 days. Conventional micropropagation and etiolation for 60 days were the best methods for production of plantlets of the ORN-MUT hybrid. The results of this work showed that the cultivation of shoot tips is an efficient strategy to remove the PMWaV complex and obtain healthy mother plants and can be a useful tool for other varieties of pineapple.

Morpho-physiological investigations in transgenic tomato (Solanum lycopersicum L.) over expressing OsRGLP1 gene

The OsRGLP1 gene was overexpressed under the control of CaMV 35S promoter in tomato (Solanum lycopersicum L.) plants using Agrobacterium-mediated transformation. The transgene expression was validated using RT-qPCR (real-time quantitative polymerase chain reaction) in the transgenic plants. Noticeable morpho-physiological traits, higher SOD activity, and elevated histological H2O2 were manifested by transgenic tomato lines. An increase in total chlorophyll and relative water content (RWC) in the leaves of transgenic lines was noted. The electrolytic leakage/conductivity (EC) in leaves of transgenic lines was lower than the control. The transgenic tomato lines showed dwarf phenotypic features in vegetative and floral traits. Interestingly, the vascular cambium regions in cross sections of stem showed secondary growth in radial symmetry. The transgenic lines also produced higher density and diversity of trichomes. The differences observed in transgenic lines are quite interesting which need to be further explored referring to the functional aspects of the transgene with reference to stress.

On the use of tree‐ring area as a predictor of biomass accumulation and its climatic determinants of coffee tree growth

AbstractThe use of growth rings dimensional parameters has been an important tool for the understanding of growth, biomass allocation and climatic characterisation of forest species. However, its potential is unknown in perennial crops of socio‐economic importance, such as coffee. This work aimed to understand how the analysis of the growth rings can be used as a proxy to understand the climatic determinants of vegetative growth and biomass allocation in the different organs of coffee trees. The work was carried out in the southern region of Minas Gerais, Brazil. The structure of the growth rings of cross sections of the orthotropic stem of coffee trees (Coffea arabica L. cv. Arara) were analysed from 2011 to 2018, using standard dendrochronological techniques. Each year in that period was characterised climatically and by its bienniality. Pearson correlation statistical analysis was used for mapping the relation among annual radial growth rates of the trees and other assessed parameters as primary growth data, accumulated biomass and the climatic characteristics of the region on an annual and intra‐annual scale. During the study the water balance (conditioned by its components, Prec and ETo) and the maximum temperature were the main determinants of the characteristics of the formed ring and the plant biomass allocation. These growing characteristics were also influenced by the phenology that modulates the vegetative/reproductive growth cycles and in turn the biennial production cycles. The results show the potential of tree rings and dendrochronology as a tool that allows indirect, but long‐term, assessment of biomass allocation and growth in coffee trees.

Heartwood variations in mid-aged plantations of Erythrophleum fordii

Erythrophleum fordii Oliv. (Caesalpiniaceae) is a rosewood species naturally distributed in southeast Asia and south China, and the heartwood is commonly used for high-quality crafts and furniture. While there are differences in heartwood development among single trees with distinct social status, the relationship between heartwood development and growth performance remains unclear. This information is essential to improve plantation management for high-yield heartwood production. Forty dominant, intermediate and suppressed trees were sampled from E. fordii plantations aged in 32–35 years in Pingxiang City, Guangxi, China. Stem analysis was carried out to determine horizontal and vertical variations of heartwood and sapwood. Number of annual rings, diameter and area of heartwood and sapwood as well as ratios of heartwood diameter and area at breast height were all significantly influenced by the social status of trees in stands (P < 0.05). In these mid-aged plantations, E. fordii stems developed heartwood once the xylem diameter reached 5–10 cm, and then heartwood diameter and area increased with increasing xylem diameter. Heartwood ring numbers, diameter and area as well as their ratios decreased with increasing height, while sapwood ring numbers and diameter were relatively constant within the section where heartwood occurred. Heartwood and sapwood diameters were equal at heights of approximately 6-m for dominant, 5-m for intermediate and 3-m for suppressed trees. Dominant trees differed considerably from intermediate and suppressed trees in heartwood volume, while heartwood volume ratios were all below 30%, and near 90% in the stem section below 8-m height regardless of social status. Relationship analysis showed that DBH was the most important factor influencing heartwood in even-aged stands. The findings provide evidence for crop tree selection, thinning regimes and reasonable management of plantations of E. fordii.

Identification and fine mapping of a multi‐tillering semi‐dwarf gene in rice

Plant height is one of the most important agronomic traits of rice. So far, more than 80 genes related to dwarf mutants had been cloned in rice, but most of them cause severe dwarf and other adverse phenotypes, which is difficult to apply in rice breeding. Here, we identified a novel multi-tillering semi-dwarf line sde, a near-isogenic line of ZX5T. Compared with ZX5T, sde performed proportionally shortened internodes. Thus, sde is a semi-dwarf of “dn” type. The longitudinal sections of stem showed that the decrease of cell number should be the major mechanism for sde semi-dwarfism. Moreover, sde was insensitive to exogenous GA3 and GR24. Genetic analysis revealed that sde was controlled by single recessive nuclear gene. To isolate SDE gene, a map-based cloning method was employed using F2 recessive plants derived from a cross between sde and NJ6. Finally, the target SDE gene was located to a 58 Kb region on the short arm of chromosome 6. There were 9 predicted opening reading frames located in this region, but only one nucleotide substitution (C to T) has been detected in the first exon of Os06g0154200 between sde and ZX5T, which result in a substitution of amino acid (R to W). Additionally, expression of Os06g0154200 in the culm and panicle of the sde was significantly increased compared to ZX5T. Interestingly, SDE shared the common locus with tillering dwarf mutant DWARF3 (D3) gene, suggesting sde may be a novel weak allelic of D3. Collectively, we here identified a novel multi-tillering semi-dwarf line sde, which would provide novel dwarf source and improving the genetic diversity for important agronomic traits of rice and the main component of plant architecture.

Cold acclimation and deacclimation in wild blueberry: Direct and indirect influence of environmental factors and non-structural carbohydrates

Through the annual cycle of plant growth and dormancy, the winter season leads to profound metabolic changes allowing plants to undergo cold acclimation. In boreal environments, winter conditions are changing rapidly and are likely to cause damage to commercial wild lowbush blueberry. In this study, we addressed the level of frost hardiness and determined the role of environmental factors and nonstructural carbohydrates (NSCs) on frost hardiness. From autumn to spring, stem sections of Vaccinium angustifolium and Vaccinium myrtilloides were harvested each month in a commercial blueberry field to assess the relative electrolyte leakage and calculate the temperature at which 50% of the cells are lysed [LT50 ( °C)], used as frost hardiness index. Stems were also collected to assess soluble carbohydrates and starch. Correlations, principal component analysis (PCA) and structural equation modeling (SEM) were used to determine how environmental factors and NSCs directly or indirectly influence the frost hardiness index. Frost hardiness reached its lowest level in December and January with LT50 dropping below -60 °C. Seasonality of frost hardening was closely linked to photoperiod and temperature, generating clock-wise hysteretic loops that divide frost hardening into acclimation, from September to January, and deacclimation, from January to the end of May. Environmental factors such as photoperiod and temperature were more important in determining the level of frost hardiness during acclimation, with either direct or indirect effect through an influence on starch degradation, increasing soluble carbohydrate content. During deacclimation, soluble carbohydrates, especially raffinose, further induced a stronger direct regulation of frost hardiness. Direct biological regulation through raffinose defined the level of frost hardiness during deacclimation. However, the negative influence of temperature on raffinose concentration could increase vulnerability to winter warming events.

Association Mapping of Verticillium Wilt Disease in a Worldwide Collection of Cotton (Gossypium hirsutum L.).

Cotton (Gossypium spp.) is the best plant fiber source in the world and provides the raw material for industry. Verticillium wilt caused by Verticillium dahliae Kleb. is accepted as a major disease of cotton production. The most practical way to deal with verticillium wilt is to develop resistant/tolerant varieties after cultural practices. One of the effective selections in plant breeding is the use of marker-assisted selection (MAS) via quantitative trait loci (QTL). Therefore, in this study, we aimed to discover the genetic markers associated with the disease. Through the association mapping analysis, common single nucleotide polymorphism (SNP) markers were obtained using 4730 SNP alleles. As a result, twenty-three markers were associated with defoliating (PYDV6 isolate) pathotype, twenty-one markers with non-defoliating (Vd11 isolate) pathotype, ten QTL with Disease Severity Index (DSI) of the leaves at the 50–60% boll opening period and eight markers were associated with DSI in the stem section. Some of the markers that show significant associations are located on protein coding genes such as protein Mpv17-like, 21 kDa protein-like, transcription factor MYB113-like, protein dehydration-induced 19 homolog 3-like, F-box protein CPR30-like, extracellular ribonuclease LE-like, putative E3 ubiquitin-protein ligase LIN, pentatricopeptide repeat-containing protein At3g62890-like, fructose-1,6-bisphosphatase, tubby-like F-box protein 8, endoglucanase 16-like, glucose-6-phosphate/phosphate translocator 2, metal tolerance protein 11-like, VAN3-binding protein-like, transformation/transcription domain-associated protein-like, pyruvate kinase isozyme A, ethylene-responsive transcription factor CRF2-like, molybdate transporter 2-like, IRK-interacting protein-like, glycosylphosphatidylinositol anchor attachment 1 protein, U3 small nucleolar RNA-associated protein 4-like, microtubule-associated protein futsch-like, transport and Golgi organization 2 homolog, splicing factor 3B subunit 3-like, mediator of RNA polymerase II transcription subunit 15a-like, putative ankyrin repeat protein, and protein networked 1D-like. It has been reported in previous studies that most of these genes are associated with biotic and abiotic stress factors. As a result, once validated, it would be possible to use the markers obtained in the study in Marker Assisted Selection (MAS) breeding.

The BpMYB4 Transcription Factor From Betula platyphylla Contributes Toward Abiotic Stress Resistance and Secondary Cell Wall Biosynthesis.

The MYB (v-myb avian myeloblastosis viral oncogene homolog) family is one of the largest transcription factor families in plants, and is widely involved in the regulation of plant metabolism. In this study, we show that a MYB4 transcription factor, BpMYB4, identified from birch (Betula platyphylla Suk.) and homologous to EgMYB1 from Eucalyptus robusta Smith and ZmMYB31 from Zea mays L. is involved in secondary cell wall synthesis. The expression level of BpMYB4 was higher in flowers relative to other tissues, and was induced by artificial bending and gravitational stimuli in developing xylem tissues. The expression of this gene was not enriched in the developing xylem during the active season, and showed higher transcript levels in xylem tissues around sprouting and near the dormant period. BpMYB4 also was induced express by abiotic stress. Functional analysis indicated that expression of BpMYB4 in transgenic Arabidopsis (Arabidopsis thaliana) plants could promote the growth of stems, and result in increased number of inflorescence stems and shoots. Anatomical observation of stem sections showed lower lignin deposition, and a chemical contents test also demonstrated increased cellulose and decreased lignin content in the transgenic plants. In addition, treatment with 100 mM NaCl and 200 mM mannitol resulted in the germination rate of the over-expressed lines being higher than that of the wild-type seeds. The proline content in transgenic plants was higher than that in WT, but MDA content was lower than that in WT. Further investigation in birch using transient transformation techniques indicated that overexpression of BpMYB4 could scavenge hydrogen peroxide and O2.– and reduce cell damage, compared with the wild-type plants. Therefore, we believe that BpMYB4 promotes stem development and cellulose biosynthesis as an inhibitor of lignin biosynthesis, and has a function in abiotic stress resistance.

The Effect Of MSG (Monosodium Glutamate) And Origin Of Stem Cutting On Growth Moringa Olifera (Moringa) Plant Seeds

Moringa olifera is known worldwide as a nutritious plant and WHO has introduced Moringa as an alternative food to overcome nutritional problems (malnutrition). Moringa plants are sought after because they can be processed into a variety of herbal medicines to raw materials for skincare products. "Moringa seeds and leaves are in a trend to be used for processed skincare products because of the nutrients they contain. This research was conducted from March 2020 until June 2020 in the village of Sei Karang, Stabat Subdistrict, Langkat Regency using a factorial randomized block design with 2 levels of treatment ie without MSG (P0), 2 g / 5 liters of water (P1), 5 g / 5 liters of water (P2), 7 g / 5 liters of water (P3), and stem cuttings (W1), middle cuttings (W2) and tip cuttings (W3). The results showed that the treatment of cuttings in the middle (W1) showed the highest with a value of 9.67 on the observation of the number of shoots, while the interaction of MSG and the origin of cuttings showed a significant effect on the emergence of the highest treatment shoots at P1W1 (2.5 g / 5 liters of water and stem section) with a value of 12.67 days and observation of root length in the P2W2 treatment (5 g / 5 liters of water and the middle section) with a value of 10.67

Multivariate Raman mapping for phenotypic characterization in plant tissue sections

Identifying and characterizing the biochemical variation in plant tissues is an important task in many research fields. Small spectral differences of the plant cell wall that are caused by genetic or environmental influences may be superimposed by individual variation as well as by a microscopic heterogeneity in molecular composition and structure of different histological substructures. A set of 56 samples from Cucumis sativus (cucumber) plants, comprising a total of ~168,000 spectra from tissue sections of leaf, stem, and roots was investigated by Raman microspectroscopic mapping excited at 532 nm. A multivariate analysis was carried out in order to assess the variation of the spectra with respect to origin of the tissue, the histological (cell wall) substructures, and the possibility to discriminate the spectra obtained from different individuals that had been subjected to two different conditions during growth. Combining the results of principal component analysis (PCA) based classification with the original spatial information in the maps of 23 sections of leaf xylem, variation in cell wall composition is found for four different individuals that also includes a discrimination of tissue grown in the presence and absence of additional silicic acid in the irrigation water of the plants. The spectral data point to differences in a contribution by carotenoids, as well as by hydroxycinnamic acids to the spectra. The results give new insight into the chemical heterogeneity of plant tissues and may be useful for elucidating biochemical processes associated with biomineralization by vibrational spectroscopy.