Rapid Propagation Research Articles

GROWTH ACCELERATION AND GALANTHAMINE CONTENT OF HIPPEASTRUM PAPILIO PLANTS GROWN ON HYDROPONIC SYSTEMS

Hippeastrum papilio (Ravenna) Van Scheepen (Amaryllidaceae) is an endangered endemic species from the rainforests of Brazil. It is not only an attractive ornamental plant, but the species with the highest content of the valuable alkaloid galanthaminе used for treatment of Alzheimer’s disease. The rapid propagation of the plants is crucial for biomass production as an alternative plant raw material for industrial galanthamine extraction. The aim of the present study was to accelerate the growth of H. papilio bulbs using two different hydroponic systems and to evaluate their effectiveness, as well as to determine the galanthamine content in the leaves. Differences in seedlings’ growth on Flood & Drain hydroponic system, on Cutting board hydroponic system, and in soil substrate as a control were significant (P<0.001, Anova single factor). Best results were obtained on the Cutting board hydroponic system where plant weight increased an average of 59.1 ± 24.0 times while the lowest growth was in the control, with an average weight increase of 11.1 ± 4.7 times. One month after adaptation of plants to soil substrate they were analysed by GC-MS. Galanthamine was the main alkaloid in the leaves of plants from all variants, and its content varied between 0.66% and 0.86%, which was commensurable with that of the native plants. Feasibility of soilless cultivation of in vitro propagated H. papilio bulblets was also proven.

Atmospheric pressure uniform dielectric barrier discharge (DBD) in a wide air gap initiated from a narrow starting point

Generating a uniform non-equilibrium plasma in atmospheric pressure air has always been a challenge. It is believed that the maximum spacing for generating a uniform non-equilibrium plasma in atmospheric pressure air, whether using AC or nanosecond pulse drive, is 4 mm. Discharges are always non-uniform when the spacing is greater than 4 mm. In this paper, we propose a new type of dielectric barrier discharge structure to address this challenge. The left end of the structure rapidly increases the discharge spacing from 0.5 mm to 6 mm, while the right side of the main discharge gap maintains a uniform spacing of 6 mm. Nanosecond pulse voltage is used to drive the plasma, an ICCD camera is used to capture the image of the plasma during a discharge pulse cycle, which indicates that a uniform plasma within the 6 mm spacing of the main discharge gap is generated. Upon further reducing the ICCD camera’s exposure time to 20 ns, it is revealed that the uniform plasma is formed due to the rapid propagation of the plasma from left to right at a speed of order of 105 m s−1. Due to the small transverse component of the external electric field, this rapid propagation behavior cannot be due to the external electric field. Therefore, this paper further proposes the hypothesis of electric dipole formation leading to this fast propagation. The hypothesis suggests that the charge separation on the surface of the anode forms an electric dipole, which generates a local discharge at its right end. This local discharge further triggers the discharge in the main gap, and the main gap discharge, in turn, forms a dipole due to charge separation again, by repeating this cycle, the plasma propagates rapidly to the right. Further analysis demonstrates that this dipole can indeed produce a strong electric field of up to 41 kV cm−1 at its right end, which is sufficient to induce a local discharge. Moreover, under such a strong electric field, the electron migration rate can indeed reach 105 m s−1. These findings support the plausibility of this hypothesis.

Exposure of Caralluma tuberculata to biogenic selenium nanoparticlesas in vitro rooting agent: Stimulates morpho-physiological and antioxidant defense system.

The commercial-scale production of Caralluma tuberculata faces significant challenges due to lower seed viability and sluggish rate of root growth in natural conditions. To overcome these obstacles, using phyto-mediated selenium nanomaterials as an in vitro rooting agent in plant in vitro cultures is a promising approach to facilitate rapid propagation and enhance the production of valuable therapeutic compounds. This study aimed to investigate the impact of phytosynthesized selenium nanoparticles (SeNPs) on the morphological growth attributes, physiological status, and secondary metabolite fabrication in in vitro propagated Caralluma tuberculata. The results demonstrated that a lower dose of SeNPs (100 μg/L) along with plant growth regulators (IBA 1 mg/L) had an affirmative effect on growth parameters and promoted earliest root initiation (4.6±0.98 days), highest rooting frequency (68.21±5.12%), number of roots (6.3±1.8), maximum fresh weight (710±6.01 mg) and dry weight (549.89±6.77 mg). However, higher levels of SeNPs (200 and 400 μg/L) in the growth media proved detrimental to growth and development. Further, stress caused by SeNPs at 100 μg/L along with PGRs (IBA 1 mg/L) produced a higher level of total chlorophyll contents (32.66± 4.36 μg/ml), while cultures exposed to 200 μg/L SeNPs alone exhibited the maximum amount of proline contents (10.5± 1.32 μg/ml). Interestingly, exposure to 400 μg/L SeNPs induced a stress response in the cultures, leading to increased levels of total phenolic content (3.4 ± 0.052), total flavonoid content (1.8 ± 0.034), and antioxidant activity 82 ± 4.8%). Furthermore, the combination of 100 μg/L SeNPs and plant growth regulators (1 mg/L IBA) led to accelerated enzymatic antioxidant activities, including superoxide dismutase (SOD = 4.4 ± 0.067 U/mg), peroxidase dismutase (POD = 3.3 ± 0.043 U/mg), catalase (CAT = 2.8 ± 0.048 U/mg), and ascorbate peroxidase (APx = 1.6 ± 0.082 U/mg). This is the first report that highlights the efficacy of SeNPs in culture media and presents a promising approach for the commercial propagation of C. tuberculata with a strong antioxidant defense system in vitro.

Impact of multiple weak layers on deformation of the interior of Qaidam Basin, northern Tibetan Plateau

The Qaidam Basin is the largest sedimentary basin within the Tibetan Plateau, with up to ∼15-km-thick deposits accumulated in the Cenozoic. Understanding how it deformed in response to the far-field effects of India-Eurasia collision is critical to improving our knowledge of the mechanism underlying northward plateau growth. Unlike typical compressional basins, where upper-crustal deformation concentrates at their margins, the Qaidam Basin features the development of many NW- to WNW-striking folds across the entire basin. Why crustal shortening occurred in the interior of Qaidam Basin, ∼100 km away from the margins, together with the underground geometries beneath these folds, remains unknown. Herein, based on newly acquired three- and two-dimensional (3-D and 2-D) seismic reflection data, borehole logging, and scaled physical analog modeling, we investigated the geometries, kinematics, and formation mechanisms of the folds within the interior of Qaidam Basin. For the first time, we reveal three local weak layers in the Lulehe, Upper Xiaganchaigou, and Shangyoushashan Formations, respectively. They consist mainly of mudstone intercalated with evaporites and limestones, and they have different spatial distributions that are likely confined by major faults and folds. These mechanically weak layers became locally thickened or thinned in response to tectonic loading and/or facilitated detachment slip to form many décollement folds that were observed at the surface. The shallow deformation above the weak layers is largely decoupled from underlying basement-involved faulting and folding, which mostly terminate upward in these weak layers. Analog modeling results suggest that the lowermost and widely distributed décollement layer in the Lulehe Formation likely facilitated long-distance rapid propagation of deformation into the basin interior. In sum, our study highlights the significance of multiple weak layers during Cenozoic deformation in the Qaidam Basin interior.

Origin of surface oxidation induced the nucleation and propagation of microcracks in TNM alloy

This study investigated the impact of surface degradation caused by oxygen (O) and nitrogen (N) elements in the environmental atmosphere on the service failure of nearly lamellar TNM alloy. The results show that oxidation-induced phase transformations at the surface and subsurface regions strongly affect the alloy's tensile properties at high temperatures. The precipitation of Al2O3, which disrupts the integrity of the Ti2AlN layer, has a weaker deformation resistance capacity compared to the Z-phase. Under stress conditions, numerous dislocations concentrate at the Al2O3 phase, causing Al2O3 particles to easily detach and initiating crack nucleation at the Z-phase/Al2O3 interface. This is the origin of oxidation failure. Cracks nucleate at the Al2O3 detachment region, propagate, and connect with surface microcracks induced by the rough and loose outer oxide layer structure. This leads to the rapid propagation of cracks into the subsurface. The consumption of β-stabilizing elements at the surface, along with the internal diffusion of O and N elements into the subsurface region, results in the formation of the hard brittle Z-phase at the subsurface lamellar structure and a transition from β0 to α2 at the lamellar colony boundaries. The precipitation of α2 and Z-phase also accelerates crack propagation. In summary, the failure mode shifts from toughness fracture to brittle fracture.

Limits to knickzone retreat and bedrock river incision on the Hawaiian islands

AbstractA knickzone is defined as a waterfall or an oversteepened fluvial reach encompassing a series of waterfalls. Knickzones are remarkable landforms in that they may represent diametrically opposed conditions: either rapid upstream propagation of base‐level fall or a condition of stability and stalled response to base‐level fall. Knickzones on the Hawaiian islands exhibit evidence of both behaviours, and in this study, we explore whether this dichotomy can be explained by a threshold stream power for river incision. Topographic analysis shows that the transition between fluvial hanging valleys, where no measurable upstream retreat from the stream junction or coastline has occurred, and knickzones that have retreated or formed upstream of their outlet can be defined by a range of catchment sizes from ~0.5 to 6 km2. This transition is present on all volcanoes in our analysis regardless of significant base‐level fall, and there is no clear trend of drainage area above knickzones with volcano age. To explain these observations, we hypothesize that knickzones form or stabilize where maximum unit stream power ( ) does not exceed the critical unit stream power required to incise bedrock . Using estimates of a maximum possible flood discharge as a function of drainage area to calculate , we show that drainage areas above knickzones are well described by the theoretical prediction that incision stalls when , where falls in a narrow range from 14 to 40 kW/m2. Furthermore, we demonstrate that knickzone positions are largely insensitive to mean climate conditions, likely reflecting the fact that extreme flood events are either insensitive or inversely correlated with mean annual rainfall.

In vitro Callus Regeneration and Chlorophyll Content Estimation in Glycine max (L.) variety from Uttarakhand, India

Soybean (Glycine max) is considered one of the most substantial produced crops across the globe because of its high nutritional value. It is a great alternative for lactose-intolerant patients and vegans to fulfil their daily protein requirements. Soybean has various varieties depending upon the colour of their seed coat. In the past few years, the consumption of Soybean has increased which demands higher production, better yield, and better seed quality. Conventional propagation methods fail to fulfil such demands. The alternate method of plant tissue culture ensures rapid mass propagation, better yield, and quality of the plants. However, the technique is often beset with challenges of low-field performance of tissue culture-raised plants due to defective chloroplast machinery. The present study investigates the effect of various plant growth regulators (PGRs) on in vitro propagation of soybean cultivars from different regions of Uttarakhand, India, and their effect on chlorophyll content in the regenerated tissues.

ВВЕДЕНИЕ В КУЛЬТУРУ IN VITRO И МИКРОКЛОНАЛЬНОЕ РАЗМНОЖЕНИЕ БОЛЬШЕГОЛОВНИКА СЕРПУХОВИДНОГО STEMMACANTHA SERRATULOIDES (GEORGI) M. DITTRICH

Stemmacantha serratuloides (Georgi) M. Dittrich is a perennial herbaceous medicinal plant, a source of a number of phytoecdysteroids with adaptogenic, anabolic and tonic effects. Due to the rarity of this plant species and the strong dependence of its seed productivity on weather conditions, the relevance of research aimed at its biotechnological cultivation and reproduction is high. The aim of this study was to introduce S. serratuloides plants from the Cis-Ural population of the Republic of Bashkortostan into in vitro culture and to develop an effective protocol for micropropagation of this species. It was shown that an effective method of preparing seeds for in vitro culture is their successive sterilization with 96% ethanol (1 min) and 20% bleach (20 min), as well as me- chanical scarification, without a preliminary stratification step. When using 1 mg/l of 2,4-dichlorophenoxyacetic acid and 1.5 mg/l of 6-benzylaminopurine on Murashige-Skoog medium, no regeneration of shoots on explants of cotyledons and hypocotyls occurred. Shoot regeneration was induced from root explants using Murashige-Skoog medium supplemented with 6-benzylaminopurine and indoleacetic acid at concentrations of 1 mg/l and 1.5 mg/l, respectively. Rooting of shoots was carried out on MS medium containing 0.25 mg/L IAA. This micropropagation technology can be used for rapid propagation of plants for various biotechnological purposes, for example, for further transformation by Agrobacterium rhizogenes and creating of hairy root cultures.

Cutting propagation of Bornmuellera tymphaea, a nickel hyperaccumulator for use in agromining: Effects of rooting media and auxins on stem cuttings

AbstractThe nickel hyperaccumulator Bornmuellera tymphaea has been evaluated for use in agromining in Greece with very promising results. This study examines propagation of this species based on cuttings, which provides rapid multiplication and clonal propagation of genotypes with useful genetic traits and offers obvious advantages over propagation by seed. Apical cuttings, 10 cm long, obtained from plants in the field, were propagated on mist benches under greenhouse conditions. Four treatments based on the rooting medium were evaluated: (a) perlite, (b) perlite + peat 1:1 (v/v), (c) ultramafic soil, and (d) ultramafic soil + perlite 1:1 (v/v). Completely randomized blocks were used in a 4 × 2 factorial design, using 4 different propagation rooting media and 2 levels of auxins (with or without the use of indole‐3‐butyric acid [IBA]), with 3 replicates of 28 cuttings. The response to perlite medium was best in terms of rooting: 75% without IBA and 71.33% with IBA, and the dry weight of roots was 0.18 g and of shoots 0.34 g. Perlite + peat 1:1 (v/v) medium also resulted in rooting in more than 55% of cuttings whereas cuttings grown in ultramafic soil showed very low rooting (<27%). Based on the findings, B. tymphaea has an aptitude for vegetative propagation by cuttings with survival values and rooting greater than 70%. Perlite combined with the application of auxin (ΙΒΑ) is recommended.

In-situ X-ray computed tomography of high-temperature tensile behavior for laser powder bed fused Invar 36 alloy

The laser powder bed fusion (PBF-LB) process provides great potential for additive manufacturing of Invar 36 alloy, which possesses a unique low coefficient of thermal expansion. However, the high-temperature tensile behavior of PBF-LB processed Invar 36 alloy has not been explored, severely restricting its applications. Hence, herein, in-situ X-ray computed tomography (XCT) tensile tests were conducted at 200 °C and 600 °C for PBF-LB processed Invar 36 alloy, and the microstructure after heat treatment, fracture morphology, post-mortem microstructure, and nano-precipitates were observed. The in-situ XCT analysis of damage evolution reveals that the tensile behavior at elevated temperatures is sensitive to numerous closely spaced lack-of-fusion (LOF) pores with relatively large equivalent diameters, distributed in the adjacent melt pools or deposited layers. These LOF pores promote the stress concentration and facilitate rapid crack propagation, resulting in a significantly diminished strength and ductility. In contrast, the small number of metallurgical and keyhole pores, possessing large spacing and relatively high sphericity, have negligible influence on the tensile behavior. Therefore, Invar 36 alloy with only metallurgical and keyhole pores can be considered defect-free, displaying an excellent yield strength of 360.0 MPa and a considerable elongation of 65.0% at 200 °C. However, as the temperature increases to 600 °C, both the yield strength and elongation show a marked decrease to 150.0 MPa and 5.4%, respectively. This weakening is accompanied by the observation of a brittle fracture and the formation of secondary cracks. The degradation in mechanical properties can be attributed to the decomposition of Cr-containing SiP2O7, which leads to the formation of numerous small-sized SiO2 and P2O5 precipitates at 600 °C. These precipitates induce embrittlement of the grain boundaries and contribute to the formation of secondary cracks. The anomalous brittle fracture observed is attributed to the intergranular fracture mode, which results from the low grain boundary energy as well as the decomposition of nanoprecipitates. Additionally, the perpendicular orientation of flatter columnar grain boundaries to the loading direction plays a role in the formation of secondary cracks. This high-temperature mechanical performance of strength, elongation, failure mode, and corresponding microcosmic mechanism advances the understanding and widespread application of PBF-LB processed Invar 36 alloy.

Dominance by cyanobacteria in the newly formed biofilms on stone monuments under a protective shade at the Beishiku Temple in China

Following the installation of a protective shade, rapid propagation of microorganisms showing in black and grey colors occurred at Beishiku Temple in Gansu Province of China. This study employed a combination of high-throughput sequencing technology, morphological examinations, and an assessment of the surrounding environmental condition to analyze newly formed microbial disease spots. The investigation unveiled the responsible microorganisms and the instigating factors of the microbial outbreak that subsequently to the erection of the shade. Through comparison of bioinformatics, the ASV method surpasses the OTU method in characterizing community compositional changes by the dominant microbial groups, the phylum Cyanobacteria emerged as the most dominant ones in the microbial community accountable for the post-shade microbial deterioration. The black spot and grey spot are predominantly composed of Mastigocladopsis and Scytonema, respectively. Validation analysis, based on the active RNA-level community results, supported and validated these conclusions. Comparative scrutiny of the microbial community before shade installation and the background environmental data disclosed that the erection of the shade prompted a decrease in temperatures and an increase in humidity within the protected area. Consequently, this spurred the exponential proliferation of indigenous cyanobacteria in the spots observed. The outcomes of this study carry considerable significance in devising preventive conservation strategies for cultural heritage and in managing the process of biodeterioration.

The Low‐Temperature Toughness Improvement of High‐Strength Low‐Alloy Steel Due to the Microstructural Changes Caused by the Reheating/Rolling Temperature

Herein, the microstructure, low‐temperature toughness, and fracture characteristics of high‐strength low‐alloy (HSLA) steel prepared by various thermomechanical control processes are systematically studied. Three different reheating/rolling temperatures are designed to obtain microstructures with different prior austenite grain sizes: 20.12 μm (S810), 27.58 μm (S910), and 35.19 μm (S1010). After hot rolling, S810 steel with smaller prior austenite grain size can provide high‐density deformed grain boundaries that promote ferrite phase transformation. The S910 and S1010 steels predominantly undergo bainite transformation as the prior austenite grain size and rolling temperature increase. Also, excellent low‐temperature toughness is obtained by reducing the reheating/rolling temperature (i.e., S810 steel), reflecting that Charpy impact energy of the core of the steel plate is 118.53 J at −120 °C. High performances is mainly attributed to the higher ferrite content, grain refinement, lower dislocation density, and higher proportion of high‐angle grain boundaries. Furthermore, fracture morphology analysis demonstrates that the S810 steel exhibits ductile fracture and noticeable plastic deformation at −120 °C, while S910 and S1010 steels exhibit brittle fracture and rapid crack propagation. These findings manifest the applicability of the suggested technique in preparing HSLA steel with excellent low‐temperature toughness.

In vitro tetraploid induction and plant regeneration of Pinellia ternata, a pearl-like herb

Pinellia ternata (Thunb.) is a widely used Chinese medicinal herb in many countries globally. However, asexual reproduction causes the germplasm of P. ternata to degrade, and there is limited research on genetic breeding. The objective of this study is to induce tetraploid ‘Pearl’ P. ternate plants by treating leaves and tubers with colchicine to acquire superior germplasm resources. The in vitro medium for autotetraploid plants was optimized through orthogonal experiments. Subsequently, the morphology, tissues, and cells of diploid and tetraploid plants were compared. The results indicated that the number of chromosomes in diploid plants was 2n = 2x = 66, while the tetraploid plants were 2n = 4x = 132 by somatic chromosome counting and flow cytometry analysis. The leaf was more suitable than the tuber for polyploid induction, and the maximum induction rate was 29.49% when leaves were treated with a 0.05% colchicine solution for 96 h. In MS medium supplemented with 0.1 mg·L− 1 6-BA, 0.1 mg·L− 1 NAA, and 1.0 mg·L− 1 KT, tetraploid leaves successfully developed into plantlets with roots, achieving a 100% transplant survival rate. Tetraploid P. ternata exhibited larger and denser leaves, thicker petioles, and larger stomata but had shorter plants compared to diploid. Meanwhile, tetraploid leaves produced a greater number of tubers. This study induced tetraploids in P. ternata and established an artificial tetraploid rapid propagation system for P. ternata. It provided the theoretical foundation and experimental support for its genetic breeding and variety enhancement.

From Lab to Bouquet: The Biotechnological Frontier in Modern Floriculture for Sustainable and Resilient Flower Farming

Modern floriculture faces unprecedented challenges in meeting the rising global demand for flowers while addressing environmental concerns and the need for sustainability. This paper explores the transformative role of biotechnology in revolutionizing flower farming practices, offering solutions for sustainable and resilient cultivation. The integration of biotechnological tools such as genetic engineering, tissue culture, and molecular breeding techniques has opened new avenues for enhancing the efficiency and resilience of flower crops. Genetic modification allows the development of varieties with improved traits, such as disease resistance, longer vase life, and enhanced stress tolerance. Tissue culture facilitates the rapid propagation of elite plant material, ensuring consistent and high-quality flower production. Furthermore, molecular breeding enables the precise selection of desirable traits, accelerating the traditional breeding process. The use of molecular markers for disease resistance, flower colour, and fragrance can streamline the development of new flower varieties tailored to market preferences. Additionally, advanced omics technologies, including genomics, transcriptomic, and metabolomics, provide valuable insights into the molecular mechanisms underlying flower development and responses to environmental stress. Biotechnological interventions extend beyond genetic improvements, encompassing sustainable cultivation practices. Precision agriculture, enabled by sensor technologies and data analytics, optimizes resource utilization, minimizing environmental impact. Smart irrigation systems, nutrient management, and pest control strategies contribute to the efficient use of resources and reduced ecological footprint. The biotechnological frontier in modern floriculture not only addresses current challenges but also positions the industry to adapt to future uncertainties. Climate change, emerging pests, and shifting market demands necessitate resilient flower farming systems. Biotechnology offers the tools to develop adaptable flower varieties and sustainable production methods, promoting long-term ecological and economic viability.

The Impacts of Plant Growth Regulators on the Rapid Propagation of Gardenia jasminoides Ellis. in Tissue Culture

The optimization of explant selection and adjustment of plant growth regulators (PGRs) ratio may enhance the efficiency of micro-propagation of Gardenia jasminoides Ellis. The findings of the study suggest that the shoot tip proved to be the optimal explant for regenerating adventitious buds, with an impressive regeneration rate of 77.78% and the average number of adventitious buds being 2.86. The ideal medium consisted of Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurine (6-BA) at a 2 mg L−1, indoleacetic acid (IAA) at a 0.2 mg L−1, kinetin (KT) at 0.15 mg L−1, resulting in an outstanding regeneration rate of adventitious buds reaching up to 91.11%. For rooting purposes, the best medium was found be half-strength MS supplemented with indoleacetic acid (IAA) 0.5 mg L−1, achieving an rate for adventitious roots amounting to as high as 97.78%. The culture plantlets ultimately thrived, achieving an impressive transplanting survival rate of 93.33%. The application of PGRs was also found to enhance the regeneration of adventitious buds by increasing the ratios of endogenous hormones ZR/IAA and GA3/IAA. Additionally, it facilitated the differentiation of adventitious roots by elevating the ratios of endogenous hormones IAA/ZR, IAA/GA3, and ABA/GA3. Our study would provide a theoretical reference for the establishment of an efficient gardenia tissue culture system and the industrial production of gardenia.

Integrated metabolomics and transcriptomics analysis highlight key pathways involved in the somatic embryogenesis of Darjeeling tea.

Darjeeling tea is a globally renowned beverage, which faces numerous obstacles in sexual reproduction, such as self-incompatibility, poor seed germination, and viability, as well as issues with vegetative propagation. Somatic embryogenesis (SE) is a valuable method for rapid clonal propagation of Darjeeling tea. However, the metabolic regulatory mechanisms underlying SE in Darjeeling tea remain largely unknown. To address this, we conducted an integrated metabolomics and transcriptomics analysis of embryogenic callus (EC), globular embryo (GE), and heart-shaped embryo (HE). The integrated analyses showed that various genes and metabolites involved in the phenylpropanoid pathway, auxin biosynthesis pathway, gibberellin, brassinosteroid and amino acids biosynthesis pathways were differentially enriched in EC, GE, and HE. Our results revealed that despite highly up-regulated auxin biosynthesis genes YUC1, TAR1 and AAO1 in EC, endogenous indole-3-acetic acid (IAA) was significantly lower in EC than GE and HE. However, bioactive Gibberellin A4 displayed higher accumulation in EC. We also found higher BABY BOOM (BBM) and Leafy cotyledon1 (LEC1) gene expression in GE along with high accumulation of castasterone, a brassinosteroid. Total flavonoids and phenolics levels were elevated in GE and HE compared to EC, especially the phenolic compound chlorogenic acid was highly accumulated in GE. Integrated metabolome and transcriptome analysis revealed enriched metabolic pathways, including auxin biosynthesis and signal transduction, brassinosteroid, gibberellin, phenylpropanoid biosynthesis, amino acids metabolism, and transcription factors (TFs) during SE in Darjeeling tea. Notably, EC displayed lower endogenous IAA levels, conducive to maintaining differentiation, while higher IAA concentration in GE and HE was crucial for preserving embryo identity. Additionally, a negative correlation between bioactive gibberellin A4 (GA4) and IAA was observed, impacting callus growth in EC. The high accumulation of chlorogenic acid, a phenolic compound, might contribute to the low success rate in GE and HE formation in Darjeeling tea. TFs such as BBM1, LEC1, FUS3, LEA, WOX3, and WOX11 appeared to regulate gene expression, influencing SE in Darjeeling tea.

Status and prospects of yam somatic embryogenesis: a pathway for biotechnology applications

AbstractYam is an important staple in sub-Saharan Africa, but the availability of quality seed yam is majorly constrained by the low propagation ratio. This is because the propagating explant is limited to the tuber and nodal parts as yam rarely flowers. There are several reports of the use of somatic embryogenesis (SE) in the rapid propagation of different crop species and as a regenerative pathway in plant genetic engineering. However, SE deployment in yam is still at the protocol development stage. This review thus exploits the status of SE application in improving the yam propagation rate. This article reviews the potential of the various yam propagation techniques in rapidly multiplying disease-free yam with their propagating explants. The advantages SE offers are rapidly propagating yam, the factors to consider in the protocol optimization of SE application in rapidly multiplying different yam varieties, and as a platform for full utilization of genetic engineering in yam. The findings so far show that SE potentially offers a faster rate of propagating yam varieties. However, due to the differences in varietal endogenous hormonal and gene products, response to SE in yam is constrained by varietal specificity. Hence, the applicability of SE in yam is still at the protocol development state. This review, thus, presents the need for more research efforts to elucidate the molecular and phytochemical controlling mechanisms of SE in yam to improve the yam multiplication rate and lay an efficient platform for the exploitation of other biotechnological advancements in improving yam species.

Emergence of crack tip plasticity in semi-brittle α-Fe

Fractures in body-centered-cubic metals and alloys below the ductile-to-brittle transition temperature are brittle. This is theoretically explained by the notion that the critical stress intensity factor of a given crack front for brittle fracture is smaller than that for plastic deformation; hence, brittle fracture is selected over plastic deformation. Although this view is true from a macroscopic perspective, such a fracture is always accompanied by small-scale plastic deformation near the crack tip, that is, crack tip plasticity. This paper investigates the origin of this plasticity using atomistic modeling with the machine learning interatomic potential of α-Fe. Some plastic modes are activated by rapid crack propagation, whereas no plasticity is activated when the crack tips are gradually fractured. The group of activated atoms dynamically caused by brittle crack propagation was identified as the precursor of plasticity.

In vitro propagation of stone fruit rootstock cultivar Evrica 99 and its influence on some phytochemical traits of fresh apricot fruit

Background: The cultivation of stone fruits is of primary importance in Armenia. Their fruits contain antioxidants, fiber, potassium, vitamin A, C, E, minerals, etc., which have a beneficial effect on human health and prevent many diseases. The concentration of those components varies depending on ecological factors, cultivar, rootstock, cultural practices, etc. Clonal rootstocks are important for increasing orchard density, tree uniformity, and high yields, and they can also affect fruit quality. In vitro culture is a valuable method for rapid propagation of high-quality, virus free plant material. Objective: The purpose of this study was to develop in vitro production technology for the stone-fruit rootstock cultivar Evrica 99, and to determine if rootstocks affect some fresh fruit traits of ´Yerevani´ and ´Sateni´ apricot cultivars. Methods: The shoot apical meristem and lateral bud served as explants for shoot regeneration. Different sterilizing agents at various periods of exposure were used for the explant surface sterilization. Various concentrations of phytohormones, both individually and in combinations, were employed for in vitro regeneration and rooting of plants. The titratable acidity (TA), dry matter (DM), vitamin C, mineral content, total carotenoids (TC), and sugar contents were evaluated in fresh fruit. Results: The most optimal option for explant surface sterilization was the gradual application of calcium hypochlorite [Ca (ClO)2] (2.0% solution, exposure time 10 min) and ethanol (70% solution, exposure time 20 s), as a result of which we had 75.5% survival rate of explants. The efficient medium for in vitro shoot regeneration was MS supplemented with 6-Benzylaminopurine (BAP) 0.8 mg/l, Kinetin (Kin) 0.2 mg/l, and Gibberellic acid (GA3) 1.0 mg/l. The half-strength Murashige and Skoog (MS) medium containing 0.8 mg/l indole-3-butyric acid (IBA) was optimal for in vitro rooting. Rooted plants were successfully adapted with a survival rate of 85.0%. The defined method can be successfully used for 'Evrica 99' cultivar micropropagation. The results obtained showed that fruit quality strongly depended on both the varieties and the rootstock tested. Conclusion: In the current study, an alternative in vitro propagation technology for rootstock cultivar ´ Evrica 99 was developed by direct organogenesis, enabling mass-scale production of virus-free plants that is suitable for commercial purposes as well. The apricot cultivars ´Yerevani´ and ´Sateni´ grafted on the virus-free rootstock cultivar Evrica 99 showed higher fruit quality traits, which are essential for human health and diet. Keywords: ´Evrica 99, fucnctional foods, in vitro regeneration, micropropagation, plant growth regulators, stone fruit rootstock, tissue culture.

Cut, Root, and Grow: Simplifying Cassava Propagation to Scale.

Cassava (Manihot esculenta Crantz) is an essential crop with increasing importance for food supply and as raw material for industrial processing. The crop is vegetatively propagated through stem cuttings taken at the end of the growing cycle and its low multiplication rate and the high cost of stem transportation are detrimental to the increasing demand for high-quality cassava planting materials. Rapid multiplication of vegetative propagules of crops comprises tissue culture (TC) and semi-autotroph hydroponics (SAH) that provide cost-effective propagation of plant materials; however, they contrast the need for specific infrastructure, special media and substrates, and trained personnel. Traditional methods such as TC and SAH have shown promise in efficient plant material propagation. Nonetheless, these techniques necessitate specific infrastructure, specialized media and substrates, as well as trained personnel. Moreover, losses during the intermediate nursery and adaptation stages limit the overall effectiveness of these methods. Building upon an earlier report from Embrapa Brazil, which utilized mature buds from cassava for rapid propagation, we present a modified protocol that simplifies the process for wider adoption. Our method involves excising single nodes with attached leaves from immature (green) cassava stems at 2 months after planting (MAP). These nodes are then germinated in pure water, eliminating the need for specific growth substrates and additional treatments. After the initial phase, the rooted sprouts are transferred into soil within 1-8 weeks. The protocol demonstrates a high turnover rate at minimal costs. Due to its simplicity, cost-effectiveness, and robustness, this method holds significant promise as an efficient means of producing cassava planting materials to meet diverse agricultural needs.