Protoplasma最新文献

The propagation of oil palm through somatic embryogenesis is the most effective method of cloning this palm tree; however, in vitro cultivation can lead to abnormalities in plant tissue, such as hyperhydricity. The present study aimed to evaluate the difference in anatomical, morphological, and histochemical characteristics, and gene expression in normal (Nm) and hyperhydric (Hh) somatic embryos of oil palm. For this purpose, Nm and Hh somatic embryos were collected from the differentiation medium and were submitted to anatomical and histochemical analyses to assess the nucleus/cytoplasm ratio (toluidine blue), starch (Lugol), and proteins (XP), as well as ultrastructural analyses via transmission electron microscopy. Additionally, gene expression analyses were performed to gain a better understanding on the molecular aspect of hyperhydric abnormality. A higher quantity of differentiated Nm somatic embryos per explant was observed, with a germination rate close to zero in Hh somatic embryos. Additionally, a higher accumulation of proteins and starch was found in Nm somatic embryos when compared to Hh embryos. It was also noted that in Nm somatic embryos, protein reserves were primarily located in the proximal region (embryonic axis), whereas starch reserves were mainly accumulated in the distal region of the somatic embryos. Hh somatic embryos exhibit insignificant starch reserves, and a greater number of intercellular spaces were observed compared to Nm somatic embryos. However, some Hh somatic embryos displayed histochemical characteristics similar to Nm, which could explain the occurrence of reversions from the Hh state to the Nm state observed in this study. Regarding molecular analyses, the gene expression results obtained showed that out of the 19 genes analyzed, 17 were upregulated in hyperhydric embryos when compared to the control condition (normal somatic embryos). Genes involved in stress response, energy metabolism, defense, membrane transport, hormonal regulation, and development were positively regulated, especially those involved in ethylene synthesis and energetic metabolism. To the best of our knowledge, this is the first in-depth study addressing hyperhydricity in oil palm during somatic embryogenesis.

Autumn-sown forage triticale can effectively leverage the optimal light and heat conditions in Ningxia, a region that boasts an abundance of light and heat resources sufficient for a single seasonal crop, but limited for two seasons. This not only fully utilizes the limited growing season but also significantly improves grass yield and economic efficiency per unit area. To enhance triticale yield in low-light and low-temperature environments, we investigated the impact of applying different concentrations of nitrogen fertilizer on triticale forage yield. Our findings revealed that nitrogen fertilizer application significantly increased triticale biomass, with the N4 treatment group exhibiting the most profound effect. To further explore the mechanisms behind nitrogen fertilizer's regulation of triticale growth and development, we conducted transcriptomic and metabolomic studies. These studies revealed that nitrogen fertilizer application significantly heightened transcription activity and protein synthesis in triticale, fostering the development of its seeds. Additionally, appropriate concentrations of nitrogen fertilizer significantly promoted photosynthesis. Metabolomic analysis revealed that nitrogen fertilizer application increased the levels of proline and O-phosphoethanolamine, enhancing triticale's stress resistance and supporting its growth and development under adverse conditions.

Proponents of the concepts of plant intelligence and plant neurobiology often use historical sources as “evidence” and argue that eminent past scientists have supported ideas of plant intelligence, memory, learning, decision-making, agency, and consciousness. Historical sources include writings by Charles Darwin, Julius von Sachs, F. W. Went, K. V. Thimann, Barbara McClintock, and J. B. Lamarck. Advocates of plant neurobiology also argue that the ideas of J. C. Bose, an Indian scientist who is considered an important forerunner of plant neurobiology, were suppressed chiefly because of racism. Plant neurobiology has been criticized on scientific grounds, but there has not been close scrutiny of the use of historical sources as a form of evidence. We provide the first in-depth analysis of how historical sources have been used and misused, and conclude that there is a consistent pattern of distortion of these sources. Distortions include the use of erroneous quotations, alteration of quotations, selective quotations without context, and misinterpretation and exaggeration of historical statements. In the case of Bose, we show that there were legitimate scientific reasons for questioning his interpretations of botanical experiments and argue that this context cannot be ignored in evaluating contemporary responses to Bose. Overall, the common practice by proponents of plant intelligence and plant consciousness of uncritically citing the words of eminent scientists of the past, taken out of their historical context to bolster their arguments, should not be confused with scientific evidence supporting these concepts, even when the quotations, themselves, are accurate.

The Alismataceae family, widely distributed across tropical temperate swamps and wetlands, includes 15 genera post-merger with Limnocharitaceae. In Argentina, six genera are represented across three clades. Embryological characters, notably the male gametophyte and anther, are crucial in taxonomy due to their stability against environmental changes. This study aims to analyze the ultrastructure of the tapetum and pollen grain development in three economically and ecologically important species representing each clade: Sagittaria montevidensis (Clade A), Hydrocleys nymphoides (Clade B), and Alisma plantago-aquatica (Clade C). Anthers at different developmental stages were processed according to classic techniques for their observation with bright-field and transmission electron microscopy. The three studied species within the Alismataceae family exhibit similar reproductive characteristics. Seven stages of pollen grain development were identified. The microsporogenesis is successive with a regular meiosis. The ultrastructure of the tapetal cells shows similarities to other species with plasmodial tapetum. During the microspore tetrad stage, there is tapetal hyperactivity and an increase in secretion processes. In the free microspore stage, the tapetal cells lose their walls and increase the amount of rough endoplasmic reticulum forming a network of cisternae that extend into evaginations. Later cells completely invade the anther locule and fuse to form a tapetal plasmodium. No peritapetal membrane with orbicules was observed. Pollen is released at the tricellular stage. The pollen grain wall presents an ectexine with a basal layer, columellae, and tectum with supratectal spines while an endexine is not observed in any of the three species. This research enhances the understanding of tapetal cell interactions with developing pollen grains and contributes to the knowledge of the ultrastructure of plasmodial tapetum. Moreover, these findings highlight evolutionary reproductive patterns in Alismataceae, suggesting the plasmodial tapetum as a synapomorphy for the order.

Cadmium (Cd) is a heavy metal that is highly toxic to plants and animals and can accumulate in the environment as a result of industrial activities and agricultural application of some types of phosphate fertilizer. This study aimed to assess the role of sodium nitroprusside (SNP), as a source of nitric oxide (NO) in alleviating Cd stress in maize plants. Maize plants were kept in soil saturated with 40%-strength nutrient solution in a greenhouse, and cadmium nitrate, Cd(NO₃)₂, was applied at different concentrations, (0, 10, and 50 µM). Sodium nitroprusside, [Fe(CN)₅NO]·2H₂O, at concentrations of 0.05, 0.1, and 0.2 µM. Growth, leaf gas exchange, and leaf anatomy analyses were performed. The experimental design was completely randomized in a 3 × 3 factorial arrangement with five replicates. The highest concentrations of Cd and SNP reduced the total dry mass and leaf and stem dry mass but increased the allocation of biomass to the roots and stem, but the leaf allocation did not change. The application of Cd and SNP promoted an increase in gas exchange and leaf area, in addition to an increase in leaf tissue thickness and stomatal density. The presence of SNP at low concentrations reduces the toxicity of Cd, but at high concentrations, this compound can generate negative effects and even toxicity in maize plants.

Many insect-induced galls are considered complex structures due to their tissue compartmentalization and multiple roles performed by them. The current study investigates the complex interaction between Nothofagus obliqua host plant and the hymenopteran gall-inducer Espinosa nothofagi, focusing on cell wall properties and cytological features. The E. nothofagi galls present an inner cortex with nutritive and storage tissues, as well as outer cortex with epidermis, chlorenchyma, and water-storing parenchyma. The water-storing parenchyma cells are rich in pectins, heteromannans, and xyloglucans in their walls, and have large vacuoles. Homogalacturonans contribute to water retention, and periplasmic spaces function as additional water reservoirs. Nutritive storage cell walls support nutrient storage, with plasmodesmata facilitating nutrient mobilization crucial for larval nutrition. Their primary and sometimes thick secondary cell walls support structural integrity and act as a carbon reserve. The absent labeling of non-cellulosic epitopes indicates a predominantly cellulosic nature in nutritive cell walls, facilitating larval access to lipid, protein, and reducing sugar-rich contents. The nutritive tissue, with functional chloroplasts and high metabolism-related organelles, displays signs of self-sufficiency, emphasizing its role in larval nutrition and cellular maintenance. Overall, the intricate cell wall composition in E. nothofagi galls showcases adaptations for water storage, nutrient mobilization, and larval nutrition, contributing significantly to our understanding of plant-insect interactions.

The phytohormone abscisic acid (ABA) is an important regulator of plant growth, but its potential participation in the process of in vitro shoot regeneration has not to date been reported. Here, we found that ABA appeared to inhibit in vitro shoot regeneration. ABA represses the formation of stem cell niches, thereby reducing the shoot regeneration by localizing the expression of WUSCHEL (WUS). During in vitro shoot regeneration, enrichment of H3K9ac in the specific region of WUS is a necessary event for its activation which could be inhibited by exogenous ABA. These findings reveal the potential function, as well as the possible way of ABA in regulating de novo shoot regeneration in Arabidopsis.

The Vaccinium genus, with over 200 species, is prized for its fruits and traditional medicinal uses. Introduced to South America in the 1980s, it has become a significant crop, particularly in Tucumán, Argentina. Southern highbush blueberries are the most cultivated. Recent research suggests that the leaves and stems of these species contain higher levels of beneficial compounds compared to fruits. This study explores the potential of V. myrtillus L. leaves and stems, typically discarded as agricultural waste, as sources of bioactive compounds. It provides the first detailed analysis of their anatomy and chemical composition, revealing high levels of phenolic compounds with antioxidant properties. Leaf extracts show stronger antioxidant activity compared to stems. Toxicity tests on Artemia salina indicate their safety for further exploration. These findings suggest that V. myrtillus L. waste by-products could be valuable as sources of bioactive compounds, promoting their application in pharmaceuticals, food, or cosmetics industries.

Alterations in cell wall composition imply in new structural and functional traits in gall developmental sites, even when the inducer is a sucking exophytophagous insect with strict feeding sites as the aphid associated to Malus domestica Borkh. This host plant is an economically important, fruit-bearing species, susceptible to gall induction by the sucking aphid Eriosoma lanigerum Hausmann, 1802. Herein, the immunocytochemical detection of arabinogalactan-proteins (AGPs), pectins, and hemicelluloses using monoclonal antibodies was performed in samples of non-galled roots and stems, and of root and stem galls on M. domestica. The dynamics of these cell wall components was discussed under the structural and functional traits of the galls proximal, median, and distal regions, according to the proximity of E. lanigerum colony feeding site. In the proximal region, the epitopes of AGPs and homogalacturonans (HGs) are related to cell growth and divisions, which result in the overproduction of parenchyma cells both in root and stem galls. In the proximal and median regions, the co-occurrence of HGs and arabinans in the cell walls of parenchyma and secondary tissues favors the nutrient flow and water-holding capacity, while the xylogalacturonans and hemicelluloses may function as additional carbohydrate resources to E. lanigerum. The immunocytochemical profile of the cell walls support the feeding activity of E. lanigerum mainly in the gall proximal region. The similarity of the cell wall components of the gall distal region and the non-galled portions, both in roots and stems, relates to the decrease of the cecidogenetic field the more distant the E. lanigerum colony is.

This study compares oil and mucilage idioblasts occurring together in the vegetative organs of Ocotea pulchella, a Lauraceae species. Our focus is specifically on the ontogeny and developmental cytology of these secretory cells. Both types of idioblasts originate from solitary cells located in the fundamental meristem, underlying the protodermis. The growth of both types of idioblasts is asynchronous, with the oil idioblasts developing first, but their initiation is restricted to the early stages of organ development. Mucilaginous idioblasts occur exclusively in the palisade parenchyma, while oil idioblasts are scattered throughout the mesophyll, midrib, and petiole of the leaves. The lamellar secretion of mucilage idioblasts is mostly made up of polysaccharides, while the secretion of oil idioblasts is made up of terpenes and lipids. Cupule occurred only in the oil idioblasts, while suberized layers occurred in both types of cells. We found that immature oil idioblasts that are close to each other fuse; mature mucilage idioblasts have labyrinthine walls arranged in a reticulate pattern; the cells close to the oil idioblasts have a pectin protective layer; and the oil idioblasts have a sheath of phenolic cells. In contrast to previous reports, the two types of secretory idioblasts were recognized during the early stages of their development. The results emphasize the importance of combining optical and electron microscopy methods to observe the ontogenetic, histochemical and ultrastructural changes that occur during the development of the secretory idioblasts. This can help us understand how secreting cells store their secretions and how their walls become specialized.