Protoplasma最新文献

The dioecious species Ilex paraguariensis (yerba mate) holds significant economic and cultural value, yet key aspects of its reproductive development remain unresolved. This study combines histological, scanning electron microscopy (SEM), and cytogenetic analyses to elucidate floral ontogeny, microsporogenesis, and sexual differentiation in yerba mate. For both sexes, six arbitrary descriptive stages of floral development were established based on all available data. Our findings reveal that floral development follows a type I pattern, initiating as bisexual before diverging into unisexual flowers. In staminate flowers, functional androecium development coincides with early parenchymatization of the pistillode and suppression of megasporangial initiation-a potential adaptive strategy to minimise resource wastage. Cytogenetic analysis confirmed regular microsporogenesis, identified off-plate bivalents at higher frequencies than previously reported, and provided the first complete meiotic progression leading to gamete formation in this species. Besides, SEM revealed novel stephanocytic structures on pistillodes, interpreted as nectarostomata, suggesting a role in pollinator attraction. These findings challenge prior assumptions regarding nectary presence in yerba mate. In pistillate flowers, staminodes undergo abortion via tapetal degeneration and aberrant sporogenous tissue collapse before meiosis, aligning with previously defined categories of organ abortion. Sexual dimorphism emerges early and is governed by distinct mechanisms: constitutive pistillode sterility in males and selective microsporangial tissue abortion within the antherodes in females. This study advances the understanding of reproductive biology in a commercially important crop, providing key morphological and cytological insights that will guide future taxonomic, developmental, and evolutionary studies within Ilex.

The integrity of herbal products is frequently undermined by both intentional and unintentional adulteration, leading to substantial health risks and economic losses. Loop-mediated isothermal amplification (LAMP), a DNA-based molecular technique, has emerged as a formidable solution due to its simplicity, specificity, sensitivity, and ability to operate under isothermal conditions. The review critically evaluates the application of LAMP in authenticating herbal materials, showcasing its enhanced efficiency and user-friendliness compared to conventional techniques. The LAMP technique employs four to six primers that target six to eight distinct regions of the target DNA, ensuring unparalleled specificity. The amplification at a constant temperature negates the need for thermal cyclers, thus rendering it highly suitable for point-of-care applications and field-based authentication. The article presents case studies that illustrate LAMP's efficacy in detecting adulteration across traditional medicines, dietary supplements, and crude drug materials. Visualization methods in LAMP, such as turbidity, colorimetry, and fluorescence, greatly enhance its accessibility and ease of use, making it well-suited for both laboratory and field applications. Although there are limitations, such as primer design complexity and contamination risks, recent innovations, including the use of lyophilized reagents, multiplexing capabilities, and integration with mobile detection platforms, are significantly advancing the practicality of LAMP assays. This review underscores the potential of LAMP in both regulatory and commercial contexts, promoting the authenticity, safety, and quality of herbal products, thereby making a vital contribution to consumer protection and the sustainability of the herbal medicine trade.

Floral nectaries are generally linked to an exchange that facilitates pollen transport, and consequently, pollination. We have characterized the ontogenesis, histochemistry, and ultrastructure of the floral nectary of Pseudobombax longiflorum (Mart.) A. Robyns (Bombacoideae, Malvaceae) from a developmental perspective and related with secretion dynamics. Light and electron microscopies were used. The floral nectary is on the proximal and median portions of the adaxial face of the calyx. Protoderm, fundamental meristem, and procambial strands form the nectary. At maturity, it is composed of glandular claviform trichomes and nectariferous and subnectariferous parenchyma vascularized predominantly by phloem. Phenolic compounds, oils, and proteins were observed in the trichome and parenchyma cells. Druse crystals occurred in the parenchyma. Starch grains decreased in the parenchyma in pre-anthesis buds, and with the nectar exudation began. Mitochondria, ribosomes, endoplasmic reticulum, Golgi bodies, and plastids containing starch grains characterize the cytoplasm of secretory cells and the apparatus compatible with nectar production. Plamodesmata occurred between parenchyma cells, parenchyma cell and basal trichome cell, and trichome cells, indicating a symplastic pathway of the pre-nectar. The downward flow of nectar through the apoplast could be prevented by the impregnation of lipids into the anticlinal walls of the stalk cell. In trichome apical cell, nectar accumulation occurred in periplasmic and subcuticular spaces. Nectar appeared to be externalized through the cell wall and cuticle. Insights into trichome development have enhanced our understanding of the formation of functional floral nectary components and nectar secretion in Malvaceae, marking the first ontogenetic and ultrastructural study in Bombacoideae.

Calcium is a central signal regulating a plethora of cellular events. Specificity is brought about by spatio-temporal patterns, so-called signatures that are established by the activity of calcium channels residing in the membranes of different compartments. The role of two-pore calcium channels (TPC) for such signatures has been debated controversially, because evidence for localisation in both, the plasma membrane as well as in the tonoplast, has been proposed. Using a GFP fusion of the tobacco homologue NtTPC1A in the background of tobacco BY-2 cells, we show that this channel is localised at the tonoplast. This localisation depends on actin filaments, but not on microtubules, as shown by pharmacological interference. Since the construct is driven by the constitutive Cauliflower Mosaic Virus 35S promoter, we can also detect phenotypic differences, such as impaired auxin-dependent cell elongation, reduced intracellular calcium content (that can be rescued by supplementation of calcium), and partial resistance to gadolinium, inhibitors of calcium influx. We also monitored the response to harpin, an elicitor from the phytopathogenic bacterium Erwinia amylovora. Here, the overexpressor line shows a higher sensitivity indicating that NtTPC1Aparticipates in defence-related programmed cell death. The data are discussed with respect to a role of NtTPC1A for spatial calcium signatures, and the regulation of cell growth by actin and auxin.

Plants depend on nitrogen (N) to support their growth, development, and essential metabolic activities. However, the mechanisms modulating the distribution of N assimilates under supplemental N (SN) condition is unknown. This study examines carbon (C) metabolism and spatial distribution in maize seedlings subjected to three N treatments (T1 to T3): T1, 1 mM NO₃⁻ (low N, LN); T2, supplementation of 1 mM NO₃⁻ with 2 mM NO₃⁻ (1 mM NO₃⁻ → 2 mM NO₃⁻, SN); and T3, 2 mM NO₃⁻ (medium N, MN). SN treatment induced significant physiological and molecular adaptations, such as enhanced growth and total biomass under fluctuating N conditions. SN-treated plants exhibited enhanced photosynthetic activity and significantly greater accumulation of soluble sugars, sucrose, and starch compared to those under LN and MN treatments. Activities of key C metabolism enzymes, such as sucrose phosphate synthase (SPS), sucrose synthase (SuSy) and invertases (INVs), starch synthase (SS), AGPase, α-amylase (AMY) and β-amylase (BAM) were significantly upregulated, supporting efficient C metabolism. Molecular analysis revealed transcriptional reprogramming under SN, marked by the upregulation of genes related to sucrose (ZmSPS1, ZmSuSy1, ZmINVs, ZmSUT2, ZmSTP2, ZmSUC2 and ZmSWEET14) and starch (ZmSS1, ZmAGPase1, ZmAMY1 and ZmBAM1) metabolism and transport. The spatial and diurnal analysis revealed dynamic C partitioning and adaptive regulation, with SN plants maintaining higher sucrose and starch levels in the leaves, sheath and roots. These findings highlight the robust plasticity of maize C metabolism under SN conditions and provide valuable insights into optimizing nitrogen use efficiency (NUE) for sustainable crop production. Future studies will focus on exploring these adaptive mechanisms across different maize genotypes and under field conditions to improve NUE and productivity in varying N environments.

Sorghum (Sorghum bicolor L.) is a prominent cereal known for its high photosynthetic efficiency and biomass production, serving as a source of food, animal feed, fiber, and biofuels. This study aims to validate identified meta-genes associated with drought stress in sorghum. Two cultivars, Mansour (drought-tolerant) and Pegah (drought-susceptible), were subjected to drought stress at four levels (25%, 50%, 75%, and 100% of field capacity [FC]( During the 4-5 leaf stage in a greenhouse in 2021. The physiological and molecular responses of the sorghum samples were evaluated at 24, 48, 72, and 96 h post-treatment. The expression of five meta-genes was analyzed to validate these candidate genes related to drought stress tolerance in sorghum. Analysis of variance indicated that the main effects of drought, cultivar, and sampling time, as well as their interactions, had highly significant effects (P < 0.01) on most physiological and biochemical traits. The relative expression of the genes SORBI_3002G225100, SORBI_3003G332200, SORBI_3003G368300, SORBI_3010G081800, and SORBI_3004G293500 increased over time under drought stress. Proline levels, ion leakage, soluble sugars, and the activities of catalase, peroxidase, ascorbate peroxidase, and superoxide dismutase enzymes increased with the intensity of drought stress and over time. Conversely, the levels of chlorophyll a and b, carotenoids, RWC, leaf surface area, and protein content decreased under drought conditions. These results confirm the relevance of these genes in conferring drought stress tolerance in sorghum. This research provides new finding into the physiological processes and biochemical activities, alongside the validation of meta-gene expression involved in drought stress, further advancing our understanding of molecular mechanisms of the reaction of sorghum to drought stress.

The Brazilian Cerrado stands as the most biodiverse neotropical savanna, supporting a vast array of endemic species uniquely adapted to its challenging environment. These species have evolved under strong selective pressures imposed by recurrent natural disturbances, including pronounced seasonal drought, intense herbivory, and frequent fire events. Consequently, Cerrado species have evolved diverse morpho-anatomical adaptations to persist in this fire-prone ecosystem. Resprouting capacity -whether from belowground or aboveground buds-represents a key functional trait for post-disturbance regeneration. While thick bark has long been recognized as the primary mechanism protecting aerial meristematic tissues, emerging research reveals finer-scale adaptations that complement bark defenses. This study investigates the protective features of aerial buds in two herbaceous Chamaecrista species (Fabaceae) to the Brazilian Cerrado. We employed a multi-technique anatomical approach combining light microscopy, histochemical analysis, fluorescence microscopy, and scanning electron microscopy (SEM). Our results revealed the presence of secretory structures, such as colleters and extrafloral nectaries, which develop at distinct temporal stages, indicating different phases of bud protection throughout plant development. Additionally, structures such as hairy leaf primordia with phenolic compound accumulation, stipules, and accessory buds were observed, reinforcing both structural and chemical investments in the protection of aerial buds. These structures confer high resilience to intense UV radiation and herbivory, providing the species with greater resistance and the ability to withstand various environmental disturbances. These findings demonstrate that herbaceous Cerrado species employ sophisticated, multi-layered strategies for aerial bud protection, comparable in complexity to woody species. The discovery of such refined adaptive mechanisms in herbaceous and subshrub growth forms challenges the traditional woody-centered paradigm of Cerrado resilience research.

The genus Senecio, which is a basal angiosperm group, holds significant importance for evolutionary and phylogenetic research. It is notable for possessing male meiotic characteristics that are rarely observed in most angiosperms. However, the current understanding about male meiosis in Senecio remains incomplete. Here, we traced the cell morphological characteristics of microsporogenesis, and male gametophyte development of Senecio cannabifolius was observed by transmission electron microscopy. The results showed that the microspore mother cells were surrounded by callose; the cytokinesis was simultaneous; the tetrad was tetrahedral; and the mature pollen was two-celled pollen with three germination pores. During the meiosis of microspore mother cells, there were abundant organelles in the cytoplasm at leptotene stage. Obvious and clear synaptonemal complex was found in pachytene stage. In the prophase I stage, the number of organelles in the cytoplasm decreased; the cristae of mitochondria decreased; and the electron density of plastids was low. It began to recover at the metaphase I and formed an obvious organelle band in the anaphase I, which separated the two daughter nuclei and contained abundant organelles. During this period, the organelles in the cytoplasm changed regularly, which was the phenomenon of cytoplasmic reorganization. The pollen wall was formed at the late uninucleate stage; the pollen wall was mature at the binucleate microspore stage; and the pollen has abortion phenomenon. These results for the first time revealed the ultrastructure of microspores and male gametophytes during the development of S. cannabifolius and enriched the understanding of the formation of pollen grains by microspores in Compositae plants.

Desmids are valuable bioindicators in peatland ecosystems due to their sensitivity to environmental changes. In temperate and boreal wetlands, seasonal desiccation of aquatic habitats, which is increasing in frequency and severity due to ongoing climate change, is currently considered a key factor structuring the distribution of individual taxa. In this study, the desiccation tolerance of Micrasterias thomasiana and Staurastrum hirsutum isolated from contrasting hydrological environments in the peatland habitats of the Ore Mountains, Czech Republic, is investigated. Using controlled experimental conditions, we subjected both young, actively growing and old, mature cultures to four different desiccation treatments and evaluated morphology and photosynthetic performance. Our results showed that young and old cultures of both species exhibited a very similar photophysiological response. Severe desiccation led to an irreversible decline in the effective quantum yield of photosystem II in both species, resulting in cell death. Mild drought stress allowed the cultures to recover, indicating that the stress severity determines the recovery potential. Finally, prolonged desiccation resulted in irreversible damage in older cultures of both species, emphasizing the limited desiccation resilience of desmids. We observed similarities in morphology with Zygnema "pre-akinetes," but in contrast to these resilient cells, the old cells of M. thomasiana and S. hirsutum did not survive the harsher desiccation conditions. Long-term mild desiccation revealed a higher resistance of S. hirsutum, probably due to the protective role of its dense mucilage. In nature, these two species usually inhabit localities with low desiccation risk or avoid and mitigate desiccation stress through localized survival strategies.

Eriococcid-induced galls exhibit many unusual features, such as sexual dimorphism and differences in life cycle duration, which are reflected in the morphology, anatomy, and metabolism of female- and male-induced galls. These sex-based distinctions between the galls result from differential developmental processes related to the time female and male insects remain inside the gall, their feeding activity, and the degree of stress imposed on the host plant cellular machinery. We assessed the immunocytochemical and Raman spectroscopy profiles of two host plant-gall inducer systems: Annona dolabripetala (Annonaceae)-Pseudotectococccus rolliniae Hodgson and Gonçalves, and Pseudobombax grandiflorum (Malvaceae)-Eriogallococcus isaias Hodgson and Magalhães. We expected differences in the dynamics of cell wall chemical components between male and female galls, with particular effects on gall structural and functional profiles, also regarding specific constraints in each system. The epitopes of xylogalacturonans and homogalacturonans, as well as their degree of methylesterification, are affected by the sex of the gall inducers, conferring a rigid structure to the cell walls of female-induced galls in comparison with those of the male-induced galls. Raman spectroscopy detected cellulose peaks in both female- and male-induced galls, with pronounced lignin bands in female-induced galls. The sex-based chemical distinctions between female- and male-induced galls imply in differences in terms of higher rigid cell walls in the female-induced galls, which was similar for both host plants.