Journal articles on the topic 'Plant vascular tissues'
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1
Hellmann, Eva, Donghwi Ko, Raili Ruonala, and Ykä Helariutta. "Plant Vascular Tissues—Connecting Tissue Comes in All Shapes." Plants 7, no. 4 (December 13, 2018): 109. http://dx.doi.org/10.3390/plants7040109.
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For centuries, humans have grown and used structures based on vascular tissues in plants. One could imagine that life would have developed differently without wood as a resource for building material, paper, heating energy, or fuel and without edible tubers as a food source. In this review, we will summarise the status of research on Arabidopsis thaliana vascular development and subsequently focus on how this knowledge has been applied and expanded in research on the wood of trees and storage organs of crop plants. We will conclude with an outlook on interesting open questions and exciting new research opportunities in this growing and important field.
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Hewer, A., T. Will, and A. J. E. van Bel. "Plant cues for aphid navigation in vascular tissues." Journal of Experimental Biology 213, no. 23 (November 12, 2010): 4030–42. http://dx.doi.org/10.1242/jeb.046326.
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Issa, Peter P., Michael Garvey, Scott Grimmell, Pramod Pantha, Maheshi Dassanayake, and Bret D. Elderd. "Hitching a Ride: Examining the Ability of a Specialist Baculovirus to Translocate through Its Insect Host’s Food Plant." Pathogens 10, no. 11 (November 18, 2021): 1500. http://dx.doi.org/10.3390/pathogens10111500.
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Plant vascular systems can translocate the entomopathogen Bacillus thuringiensis from the soil into plant tissues. However, whether other soil dwelling entomopathogens utilize plant vascular tissue for movement has not yet been fully explored. We used Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) to evaluate whether baculoviruses, a common entomopathogen and bioinsecticide, can be transported through the plant vascular pathways of Zea mays. We found that our treatments did not allow a sufficient virus translocation into the plant to induce a lethal infection in insects, which was confirmed by a molecular analysis. While other entomopathogens translocate, baculoviruses may not be one of them.
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Qaderi, Mirwais, Ashley Martel, and Sage Dixon. "Environmental Factors Influence Plant Vascular System and Water Regulation." Plants 8, no. 3 (March 15, 2019): 65. http://dx.doi.org/10.3390/plants8030065.
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Developmental initiation of plant vascular tissue, including xylem and phloem, from the vascular cambium depends on environmental factors, such as temperature and precipitation. Proper formation of vascular tissue is critical for the transpiration stream, along with photosynthesis as a whole. While effects of individual environmental factors on the transpiration stream are well studied, interactive effects of multiple stress factors are underrepresented. As expected, climate change will result in plants experiencing multiple co-occurring environmental stress factors, which require further studies. Also, the effects of the main climate change components (carbon dioxide, temperature, and drought) on vascular cambium are not well understood. This review aims at synthesizing current knowledge regarding the effects of the main climate change components on the initiation and differentiation of vascular cambium, the transpiration stream, and photosynthesis. We predict that combined environmental factors will result in increased diameter and density of xylem vessels or tracheids in the absence of water stress. However, drought may decrease the density of xylem vessels or tracheids. All interactive combinations are expected to increase vascular cell wall thickness, and therefore increase carbon allocation to these tissues. A comprehensive study of the effects of multiple environmental factors on plant vascular tissue and water regulation should help us understand plant responses to climate change.
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Caño-Delgado, Ana, Ji-Young Lee, and Taku Demura. "Regulatory Mechanisms for Specification and Patterning of Plant Vascular Tissues." Annual Review of Cell and Developmental Biology 26, no. 1 (November 10, 2010): 605–37. http://dx.doi.org/10.1146/annurev-cellbio-100109-104107.
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Kudirka, Dalia T., and Peter L. Webster. "Temporal differences in cellular activity between tissues of the petal of Tradescantia clone 4430." Canadian Journal of Botany 68, no. 5 (May 1, 1990): 1075–79. http://dx.doi.org/10.1139/b90-134.
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Cellular behavior was analysed in different tissues of petals of Tradescantia clone 4430 during lamina development. Previous work demonstrated that a period of relatively high mitotic activity is followed by a brief period of arrest in the G1 stage of the cell cycle before a shift of cells from G1 and G2 in the mature petal. In this study, the same sequence of events was seen to occur in both provascular–vascular tissue and epidermis and mesophyll. However, analysis of mitotic frequencies, shown to reflect mitotic rates in whole petals, indicated that mitotic activity peaks later and (or) lasts longer in the provascular–vascular tissue than in the epidermis and mesophyll. Similarly, there is a corresponding delay in the subsequent shift of the cells of the provascular–vascular tissue from G1, to G2, with the result that at anthesis only about 40% of the cells of the provascular tissue have reached G2 DNA values compared with 100% of the rest of the cells of the petal.
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Schuetz, Mathias, Afsaneh Haghighi-Kia, Carol L. Wenzel, and Jim Mattsson. "Induction of xylem and fiber differentiation in Populus tremuloidesThis article is one of a selection of papers published in the Special Issue on Poplar Research in Canada." Canadian Journal of Botany 85, no. 12 (December 2007): 1147–57. http://dx.doi.org/10.1139/b07-112.
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Vascular tissues are of particular importance to terrestrial plants as they allow long-distance transport within the plant and also provide support for upright growth. Nowhere are these traits more obvious than in tree species. Here we have evaluated the role of auxin transport in the differentiation of primary and secondary vascular tissues in a tree species, trembling aspen ( Populus tremuloides Michx). We found that a partial inhibition of auxin transport resulted in increased width and numbers of veins in leaves. A similar vascular overgrowth was observed during early secondary vascular differentiation of stems. This stem overgrowth consisted almost entirely of early differentiation of metaxylem and fibers. We hypothesize that the early differentiation of metaxylem and fibers results from inhibitor-induced accumulation of auxin in stems and that the differentiation of these tissues requires higher levels of auxin exposure than protoxylem. The controlled conditions used in this study also provide a framework for reverse genetics approaches to identify genes involved in vascular differentiation based on elevated expression in tissues developing vascular overgrowth.
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Freshour, G., M. Hahn, and Z.-H. Ye. "Microscopic Examination Of Vascular Differentiation And Pattern Formation In The Inflorescence Stems Of Arabidopsis." Microscopy and Microanalysis 5, S2 (August 1999): 1284–85. http://dx.doi.org/10.1017/s1431927600019747.
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Plant vascular system is the principal means to carry water and food throughout the plant body. It is composed of two types of conducting vascular tissues, xylem and phloem. Xylem carries water and minerals from the root to the shoot, whereas phloem transports photosynthates from leaves to other parts of the body. The evolution of vascular system which solved the problem of water and food transport was considered to be one of the key events for the successful emergence of vascular plants on the land from aquatic environments. Although vascular tissues in almost all vascular plants consist of xylem and phloem, diverse arrangements of vascular tissues within the bundles and of vascular bundles in the stele were evolved (1). The occurrence of diverse vascular patterns in vascular plants offers an excellent opportunity to study the evolutionary mechanisms controlling pattern formation. In this report, we present our studies on the vascular differentiation and pattern formation in the inflorescence stems of Arabidopsis thaliana.
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Mattsson, J., Z. R. Sung, and T. Berleth. "Responses of plant vascular systems to auxin transport inhibition." Development 126, no. 13 (July 1, 1999): 2979–91. http://dx.doi.org/10.1242/dev.126.13.2979.
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To assess the role of auxin flows in plant vascular patterning, the development of vascular systems under conditions of inhibited auxin transport was analyzed. In Arabidopsis, nearly identical responses evoked by three auxin transport inhibitor substances revealed an enormous plasticity of the vascular pattern and suggest an involvement of auxin flows in determining the sites of vascular differentiation and in promoting vascular tissue continuity. Organs formed under conditions of reduced auxin transport contained increased numbers of vascular strands and cells within those strands were improperly aligned. In leaves, vascular tissues became progressively confined towards the leaf margin as the concentration of auxin transport inhibitor was increased, suggesting that the leaf vascular system depends on inductive signals from the margin of the leaf. Staged application of auxin transport inhibitor demonstrated that primary, secondary and tertiary veins became unresponsive to further modulations of auxin transport at successive stages of early leaf development. Correlation of these stages to anatomical features in early leaf primordia indicated that the pattern of primary and secondary strands becomes fixed at the onset of lamina expansion. Similar alterations in the leaf vascular responses of alyssum, snapdragon and tobacco plants suggest common functions of auxin flows in vascular patterning in dicots, while two types of vascular pattern alterations in Arabidopsis auxin transport mutants suggest that at least two distinct primary defects can result in impaired auxin flow. We discuss these observations with regard to the relative contributions of auxin transport, auxin sensitivity and the cellular organisation of the developing organ on the vascular pattern.
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Opsahl, Stephen, and Ronald Benner. "Characterization of carbohydrates during early diagenesis of five vascular plant tissues." Organic Geochemistry 30, no. 1 (January 1999): 83–94. http://dx.doi.org/10.1016/s0146-6380(98)00195-8.
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Pratt, R. G., M. R. McLaughlin, G. A. Pederson, and D. E. Rowe. "Pathogenicity of Macrophomina phaseolina to Mature Plant Tissues of Alfalfa and White Clover." Plant Disease 82, no. 9 (September 1998): 1033–38. http://dx.doi.org/10.1094/pdis.1998.82.9.1033.
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Macrophomina phaseolina has been observed on alfalfa and white clover in North America, but its pathogenicity to mature plants of these species has not been adequately documented and Koch's postulates have not been fulfilled. Isolates of M. phaseolina from alfalfa and white clover were evaluated for pathogenicity by inoculating tissues of mature plants with infested toothpick pieces. Excised leaf tissues also were inoculated with mycelium. In stolons of white clover and stems of alfalfa, M. phaseolina caused a brown-black, basipetally progressive necrosis of vascular tissue with subsequent collapse of the surrounding pith and epidermis to produce radially constricted, expanding lesions. In taproots and crowns of alfalfa, M. phaseolina caused dark discoloration of vascular tissues in bands or streaks above and below inoculation points with subsequent invasion and death of cortical tissues, lateral roots, and stems. Sclerotia formed in all tissues of both species. Excised leaf tissues were rapidly parasitized, but significant differences in rates of parasitism between genotypes suggested that differences in host resistance to M. phaseolina may be present in both species. Pycnidia formed on leaves of bean, lima bean, and cotton. All isolates of M. phaseolina were reisolated from margins of necrosis in all types of inoculated tissues and regrown in pure culture. These results fulfill Koch's postulates for M. phaseolina as a pathogen of mature white clover and alfalfa in North America, and they demonstrate its capacity to parasitize a variety of tissues of both species in the absence of other pathogens. Results indicate that M. phaseolina should be considered a potential cause for lack of persistence of white clover and alfalfa during summer months in the southeastern United States.
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Qian, Yu, Huan Feng, Frank J. Gallagher, Qingzhi Zhu, Meiyin Wu, Chang-Jun Liu, Keith W. Jones, and Ryan V. Tappero. "Synchrotron study of metal localization inTypha latifolia L. root sections." Journal of Synchrotron Radiation 22, no. 6 (October 13, 2015): 1459–68. http://dx.doi.org/10.1107/s1600577515017269.
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Understanding mechanisms that control plant root metal assimilation in soil is critical to the sustainable management of metal-contaminated land. With the assistance of the synchrotron X-ray fluorescence technique, this study investigated possible mechanisms that control the localization of Fe, Cu, Mn, Pb and Zn in the root tissues ofTypha latifolia L. collected from a contaminated wetland. Metal localizations especially in the case of Fe and Pb in the dermal tissue and the vascular bundles were different. Cluster analysis was performed to divide the dermal tissue into iron-plaque-enriched dermal tissue and regular dermal tissue based on the spatial distribution of Pb and Fe. Factor analysis showed that Cu and Zn were closely correlated to each other in the dermal tissues. The association of Cu, Zn and Mn with Fe was strong in both regular dermal tissue and iron-plaque-enriched dermal tissue, while significant (p< 0.05) correlation of Fe with Pb was only observed in tissues enriched with iron plaque. In the vascular bundles, Zn, Mn and Cu showed strong association, suggesting that the localization of these three elements was controlled by a similar mechanism. Iron plaque in the peripheral dermal tissues acted as a barrier for Pb and a buffer for Zn, Cu and Mn. The Casparian strip regulated the transportation of metals from dermal tissues to the vascular bundles. The results suggested that the mechanisms controlling metal localization in root tissues varied with both tissue types and metals.
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Bubier, Jill L., Tim R. Moore, and Gareth Crosby. "Fine-scale vegetation distribution in a cool temperate peatland." Canadian Journal of Botany 84, no. 6 (June 2006): 910–23. http://dx.doi.org/10.1139/b06-044.
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Carbon (C) modeling and carbon dioxide (CO2) flux measurements in peatlands are dependent on the distribution and productivity of vegetation in a system with a high degree of spatial variability, often linked to the position of the water table. We tested the hypothesis that at a fine-scale (tens of metres) water table position exerts a strong control on species abundance, plant biomass, particularly photosynthetically active tissues, leaf area index (LAI), and areal foliar N and chlorophyll at Mer Bleue, a cool temperate peatland in eastern Canada. Total aboveground biomass ranged from 147 to 1011 g·m–2, with shrubs contributing between 42% and 72% of the total in the transects. We found significant (P < 0.05) positive relationships between foliar and total vascular plant biomass and mean water table position, and significant decreases in the shrub foliar:woody biomass ratio and moss biomass with a lower water table. However, there was no significant relationship between water table position and photosynthetically active tissues (vascular plant leaves and moss capitulum), ranging from 114 to 672 g·m–2) and the areal mass of N in these tissues, ranging from 1.5 to 6.7 g·m–2. Multivariate analyses of vegetation and environmental data showed that species distribution could be explained by both water table and chemistry gradients and that unimodal rather than linear responses best described the species and water table relationships. LAI ranged from 0.1 to over 3 and was correlated with both water table position and with vascular foliar biomass. Percent cover of shrubs was correlated with foliar biomass and LAI. Our results suggest that the less labour-intensive estimates of percent cover can be used to predict the vascular plant foliar biomass and LAI measurements. The lack of relationship between photosynthetically active tissues, tissue N concentrations, and water table may also explain the surprising lack of spatial variability in peak growing season eddy flux net ecosystem CO2 exchange in three different areas of the peatland.
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Kappagantu, Madhu, Tamara D. Collum, Christopher Dardick, and James N. Culver. "Viral Hacks of the Plant Vasculature: The Role of Phloem Alterations in Systemic Virus Infection." Annual Review of Virology 7, no. 1 (September 29, 2020): 351–70. http://dx.doi.org/10.1146/annurev-virology-010320-072410.
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For plant viruses, the ability to load into the vascular phloem and spread systemically within a host is an essential step in establishing a successful infection. However, access to the vascular phloem is highly regulated, representing a significant obstacle to virus loading, movement, and subsequent unloading into distal uninfected tissues. Recent studies indicate that during virus infection, phloem tissues are a source of significant transcriptional and translational alterations, with the number of virus-induced differentially expressed genes being four- to sixfold greater in phloem tissues than in surrounding nonphloem tissues. In addition, viruses target phloem-specific components as a means to promote their own systemic movement and disrupt host defense processes. Combined, these studies provide evidence that the vascular phloem plays a significant role in the mediation and control of host responses during infection and as such is a site of considerable modulation by the infecting virus. This review outlines the phloem responses and directed reprograming mechanisms that viruses employ to promote their movement through the vasculature.
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Jung, Jae Hoon, and Chung Mo Park. "Vascular development in plants: specification of xylem and phloem tissues." Journal of Plant Biology 50, no. 3 (June 2007): 301–5. http://dx.doi.org/10.1007/bf03030658.
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Sanchês, Sâmara Stainy Cardoso, Ricardo Alves de Araújo, Rosane Cláudia Rodrigues, Clésio dos Santos Costa, Francisco Naysson de Sousa Santos, Ivone Rodrigues da Silva, Ana Paula Ribeiro de Jesus, and Noilson Monteles de Lima. "Quantitative anatomy and in situ ruminal degradation parameters of elephant grass under different defoliation frequencies." Revista Brasileira de Saúde e Produção Animal 19, no. 2 (April 2018): 166–77. http://dx.doi.org/10.1590/s1519-99402018000200003.
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SUMMARY This study aimed to determine the area occupied by different tissues present in the leaf blade and the in situ degradability of leaf and stem of elephant grass (Pennisetum purpureum Schum.) under different defoliation frequencies (30, 45, 60, 75 and 90 days). Plants were classified into three levels of insertion in the tiller (apical, medial and basal). The results were presented as a proportion of the area of each tissue in relation to the total area of the leaf blade, namely, parenchyma tissue (PT), lignified vascular tissue (LVT) and non-lignified vascular tissue (NLVT). The proportion of tissue in the leaf blade is altered in accordance with the insertion in the tiller and increase in cutting age of the plant. PT has greater proportion at lower cutting ages, LVT increases with frequency and NLVT is higher at 60 days. The parameters of DM degradation in the two fractions evaluated decreased significantly with increasing maturity of the plant. The effective degradability of CP in leaf and stem decreased with the increase in the rate of passage (2, 5, and 8% h-1). The highest rate (c) of CP degradation for the leaf fraction was obtained with a frequency of 60 days, for the stem, with 45 days. The advance in plant maturity increases the proportion of lignified vascular tissue, thus influencing the ruminal degradation parameters of elephant grass. The defoliation frequency of 60 days offers an optimal point regarding the proportion of anatomical tissues correlated with the degradation of elephant grass.
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Höglund, Anna-Stina, Alan M. Jones, and Lars-Göran Josefsson. "An Antigen Expressed During Plant Vascular Development Crossreacts with Antibodies Towards KLH (Keyhole Limpet Hemocyanin)." Journal of Histochemistry & Cytochemistry 50, no. 8 (August 2002): 999–1003. http://dx.doi.org/10.1177/002215540205000801.
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An antigen present in plant vascular tissue crossreacts with antibodies towards keyhole limpet hemocyanin (KLH). The antigen is present in xylem and vascular cambium, as evidenced by immunocytochemical staining of plant sections. This cell type assignment was confirmed by staining of mesophyll cell cultures from Zinnia elegans L. undergoing tracheary cell differentiation. The strongest staining both in sections and cell cultures occured in cells and tissues during early stages of differentiation. Although the anti-KLH antibodies can easily be removed by affinity purification, our findings suggest that a certain caution is needed when KLH is used as an immunological carrier for studies in plants.
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Pommerrenig, Benjamin, Kai Eggert, and Gerd P. Bienert. "Boron Deficiency Effects on Sugar, Ionome, and Phytohormone Profiles of Vascular and Non-Vascular Leaf Tissues of Common Plantain (Plantago major L.)." International Journal of Molecular Sciences 20, no. 16 (August 9, 2019): 3882. http://dx.doi.org/10.3390/ijms20163882.
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Vascular tissues essentially regulate water, nutrient, photo-assimilate, and phytohormone logistics throughout the plant body. Boron (B) is crucial for the development of the vascular tissue in many dicotyledonous plant taxa and B deficiency particularly affects the integrity of phloem and xylem vessels, and, therefore, functionality of long-distance transport. We hypothesize that changes in the plants’ B nutritional status evoke differential responses of the vasculature and the mesophyll. However, direct analyses of the vasculature in response to B deficiency are lacking, due to the experimental inaccessibility of this tissue. Here, we generated biochemical and physiological understanding of B deficiency response reactions in common plantain (Plantago major L.), from which pure and intact vascular bundles can be extracted. Low soil B concentrations affected quantitative distribution patterns of various phytohormones, sugars and macro-, and micronutrients in a tissue-specific manner. Vascular sucrose levels dropped, and sucrose loading into the phloem was reduced under low B supply. Phytohormones responded selectively to B deprivation. While concentrations of abscisic acid and salicylic acid decreased at low B supply, cytokinins and brassinosteroids increased in the vasculature and the mesophyll, respectively. Our results highlight the biological necessity to analyze nutrient deficiency responses in a tissue- rather organ-specific manner.
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Terna, Tersoo P., Nik Mohd Izham Mohamed Nor, and Latiffah Zakaria. "Histopathology of Corn Plants Infected by Endophytic Fungi." Biology 11, no. 5 (April 22, 2022): 641. http://dx.doi.org/10.3390/biology11050641.
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Endophytic fungi inhabiting plant tissues show extensive functional diversity, ranging from mutualism to pathogenicity. The present study evaluated the histological responses of corn plants to colonization by three species of endophytic fungi isolated from corn. Corn seedlings were inoculated with 1 × 106 conidia per mL spore suspensions of endophytic Fusarium verticillioides, Fusarium sacchari, and Penicillium citrinum and observed for 14 days for the emergence of disease symptoms. Histological examination of diseased root, stem, and leaf tissues was conducted using light and transmission electron microscopy. The results indicated that the mean diameters of root phloem, stem vascular bundles, and leaf vascular bundles, of corn plants infected with endophytic P. citrinum (18.91 µm, 146.96 µm, and 107.86 µm, respectively), F. verticillioides (18.75 µm, 85.45 µm, and 118.24 µm, respectively), and F. sacchari (24.15 µm root phloem, and 98.90 µm stem vascular bundle diameters), were significantly lower than the root phloem (33.68 µm), stem vascular bundle (186.77 µm), and leaf vascular bundle (155.88 µm) of the uninfected corn plants (p ≤ 0.05). Endophytic F. verticillioides was the most virulent, resulting in severe degradation and the eventual collapse of infected plant tissues. The study showed that endophytic fungi recovered from corn plants are capable of initiating significant disease responses in infected corn tissues.
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Dengler, Nancy G. "The shoot apical meristem and development of vascular architectureThis review is one of a selection of papers published on the Special Theme of Shoot Apical Meristems." Canadian Journal of Botany 84, no. 11 (November 2006): 1660–71. http://dx.doi.org/10.1139/b06-126.
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The shoot apical meristem (SAM) functions to generate external architecture and internal tissue pattern as well as to maintain a self-perpetuating population of stem-cell-like cells. The internal three-dimensional architecture of the vascular system corresponds closely to the external arrangement of lateral organs, or phyllotaxis. This paper reviews this correspondence for dicotyledonous plants in general and in Arabidopsis thaliana (L.) Heynh., specifically. Analysis is partly based on the expression patterns of the class III homeodomain-leucine zipper transcription factor ARABIDOPSIS THALIANA HOMEOBOX GENE 8 (ATHB8), a marker of the procambial and preprocambial stages of vascular development, and on the anatomical criteria for recognizing vascular tissue pattern. The close correspondence between phyllotaxis and vascular pattern present in mature tissues arises at early stages of development, at least by the first plastochron of leaf primordium outgrowth. Current literature provides an integrative model in which local variation in auxin concentration regulates both primordium formation on the SAM and the first indications of a procambial prepattern in the position of primordium leaf trace as well as in the elaboration of leaf vein pattern. The prospects for extending this model to the development of the complex three-dimensional vascular architecture of the shoot are promising.
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Lu, Kuan-Ju, Nicole van ’t Wout Hofland, Eliana Mor, Sumanth Mutte, Paul Abrahams, Hirotaka Kato, Klaas Vandepoele, Dolf Weijers, and Bert De Rybel. "Evolution of vascular plants through redeployment of ancient developmental regulators." Proceedings of the National Academy of Sciences 117, no. 1 (December 24, 2019): 733–40. http://dx.doi.org/10.1073/pnas.1912470117.
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Vascular plants provide most of the biomass, food, and feed on earth, yet the molecular innovations that led to the evolution of their conductive tissues are unknown. Here, we reveal the evolutionary trajectory for the heterodimeric TMO5/LHW transcription factor complex, which is rate-limiting for vascular cell proliferation inArabidopsis thaliana. Both regulators have origins predating vascular tissue emergence, and even terrestrialization. We further show that TMO5 evolved its modern function, including dimerization with LHW, at the origin of land plants. A second innovation in LHW, coinciding with vascular plant emergence, conditioned obligate heterodimerization and generated the critical function in vascular development inArabidopsis. In summary, our results suggest that the division potential of vascular cells may have been an important factor contributing to the evolution of vascular plants.
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Wi, Seung Gon, Kwang Ho Lee, Hyeun Jong Bae, Byung Dae Park, and Adya P. Singh. "Variability in the Distribution of Middle Lamella Lignin in Secondary Vascular Tissues of Kenaf Stems." IAWA Journal 35, no. 1 (2014): 61–68. http://dx.doi.org/10.1163/22941932-00000048.
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Lignin in the middle lamella of the secondary xylem of angiosperms appears to be inhomogeneously distributed, based on studies where the focus is on a close examinantion of the middle lamella region of fibre cell walls by transmission electron microscopy (TEM). This is in contrast to the secondary xylem of gymnosperms which often display a more uniform distribution of lignin in the middle lamella of secondary xylem elements. The aim of our study was to undertake TEM examination of kenaf (Hibiscus cannabinus L.), an angiosperm plant mainly cultivated for its high quality secondary phloem fibres, to investigate lignin distribution in the middle lamella of secondary vascular tissues, including secondary phloem fibres. The middle lamella displayed considerable heterogeneity in the distribution of lignin in all lignified secondary vascular tissues, including xylem and phloem fibres, vessels and axial xylem parenchyma cells. The results provided evidence of lignin inhomogeneity in the secondary phloem fibres as well as in other lignified elements of kenaf vascular tissues, extending previous observations which were confined only to fibre cells.
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Chamberlin, Mark A., Harry T. Horner, and Reid G. Palmer. "Nutrition of ovule, embryo sac, and young embryo in soybean: an anatomical and autoradiographic study." Canadian Journal of Botany 71, no. 9 (September 1, 1993): 1153–68. http://dx.doi.org/10.1139/b93-136.
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Photosynthesizing soybean plants were exposed to 14CO2 to study the incorporation of labeled water-insoluble photosynthates in ovules at various developmental stages. Using autoradiographic techniques on sectioned material, we show that the distribution of labeled carbon in different ovular tissues is regulated spatially and temporally. During zygote through globular stages of embryo development, labeled assimilates accumulate in integumentary tissue adjacent to the micropylar and chalazal poles of the embryo sac. A chalazal vascular trace and two adfunicular vascular strands are the pathways for accumulation of 14C in these regions. Up through the proembryo stage, movement of labeled photoassimilates into the lateral regions of the embryo sac seems blocked by a cuticle-like layer between the endothelium and embryo sac. At the globular embryo stage, the greatest accumulation of label is still at the chalazal and the micropylar ends of the embryo sac, but fragmentation of the cuticle-like barrier coincident with cellularization of endosperm allows channeling of labeled carbon from adjacent integumentary tissue into the embryo sac as well. Autoradiographic evidence for carbon flow into the embryo sac can be correlated with ultrastructural and morphological changes in time in ovular and endosperm tissues enclosing the embryo. Key words: autoradiography, embryo sac, Glycine, nutrition, ovule.
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Wenzel, Carol L., Qian Hester, and Jim Mattsson. "Identification of Genes Expressed in Vascular Tissues Using NPA-Induced Vascular Overgrowth in Arabidopsis." Plant and Cell Physiology 49, no. 3 (March 2008): 457–68. http://dx.doi.org/10.1093/pcp/pcn023.
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Laliberté, Sylvie, and Maurice Lalonde. "Histology and ultrastructure of caulogenic callus cultures of Larix ×eurolepis." Canadian Journal of Botany 68, no. 5 (May 1, 1990): 979–89. http://dx.doi.org/10.1139/b90-124.
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Caulogenic callus cultures intiated from vegetative short shoot buds of a mature Larix ×eurolepis Henry (hybrid larch) were studied by light and electron microscopy. Callus tissue showed a zonation in pigmentation, as color varied from green to tan and brown. Green areas displayed characteristics of actively growing tissues, contained numerous chloroplasts and starch granules, and showed a range in the amount of vacuolar tannin deposits. Vascular clusters were present in callus tissue associated with adventitious shoots, which were well vascularized. Tan and brown areas had massive amounts of starch granules, tannin deposits, and sclereids. Numerous cells in brown areas were in a senescent state. Browning of tissues increased with time during each subculture and was concomitant with an increase in shoot productivity. Extracellular substances were apparently extruded from primary cell walls in tan and brown areas. Key words: caulogenic calli, conifer, histology, Larix, tissue culture, ultrastructure.
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Dowd, Caitriona, Iain W. Wilson, and Helen McFadden. "Gene Expression Profile Changes in Cotton Root and Hypocotyl Tissues in Response to Infection with Fusarium oxysporum f. sp. vasinfectum." Molecular Plant-Microbe Interactions® 17, no. 6 (June 2004): 654–67. http://dx.doi.org/10.1094/mpmi.2004.17.6.654.
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Microarray analysis of large-scale temporal and tissue-specific plant gene expression changes occurring during a susceptible plant-pathogen interaction revealed different gene expression profile changes in cotton root and hypocotyl tissues. In hypocotyl tissues infected with Fusarium oxysporum f. sp. vasinfectum, increased expression of defense-related genes was observed, whereas few changes in the expression levels of defense-related genes were found in infected root tissues. In infected roots, more plant genes were repressed than were induced, especially at the earlier stages of infection. Although many known cotton defense responses were identified, including induction of pathogenesis-related genes and gossypol biosynthesis genes, potential new defense responses also were identified, such as the biosynthesis of lignans. Many of the stress-related gene responses were common to both tissues. The repression of drought-responsive proteins such as aquaporins in both roots and hypocotyls represents a previously unreported response of a host to pathogen attack that may be specific to vascular wilt diseases. Gene expression results implicated the phytohormones ethylene and auxin in the disease process. Biochemical analysis of hormone level changes supported this observation.
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Witzel, Katja, and Andrea Matros. "Fructans Are Differentially Distributed in Root Tissues of Asparagus." Cells 9, no. 9 (August 22, 2020): 1943. http://dx.doi.org/10.3390/cells9091943.
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Inulin- and neoseries-type fructans [fructooligosaccharides (FOS) and fructopolysaccharides] accumulate in storage roots of asparagus (Asparagus officinalis L.), which continue to grow throughout the lifespan of this perennial plant. However, little is known about the storage of fructans at the spatial level in planta, and the degree of control by the plant is largely uncertain. We have utilized mass spectrometry imaging (MSI) to resolve FOS distribution patterns in asparagus roots (inner, middle, and outer tissues). Fructan and proteome profiling were further applied to validate the differential abundance of various fructan structures and to correlate observed tissue-specific metabolite patterns with the abundance of related fructan biosynthesis enzymes. Our data revealed an increased abundance of FOS with higher degree of polymerization (DP > 5) and of fructopolysaccharides (DP11 to DP17) towards the inner root tissues. Three isoforms of fructan:fructan 6G-fructosyltransferase (6G-FFT), forming 6G-kestose with a β (2–6) linkage using sucrose as receptor and 1-kestose as donor, were similarly detected in all three root tissues. In contrast, one ß-fructofuranosidase, which likely exhibits fructan:fructan 1-fructosyltransferase (1-FFT) activity, showed very high abundance in the inner tissues and lower levels in the outer tissues. We concluded a tight induction of the biosynthesis of fructans with DP > 5, following a gradient from the outer root cortex to the inner vascular tissues, which also correlates with high levels of sucrose metabolism in inner tissues, observed in our study.
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Little, Stefan A., and Ruth A. Stockey. "Morphogenesis of the Specialized Peridermal Tissues in Decodon Allenbyensis from the Middle Eocene Princeton Chert." IAWA Journal 27, no. 1 (2006): 73–87. http://dx.doi.org/10.1163/22941932-90000138.
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Aquatic tissues in the submerged axes of Decodon allenbyensis Cevallos- Ferriz et Stockey are investigated and described in detail. Numerous well-preserved roots have primary aerenchymatous cortex and no secondary vascular tissues while other axes show transitions to secondary xylem and phloem, as well as periderm composed of thin-walled lacunate phellem. Phellem appears similar to the primary aerenchyma seen in aquatic roots of species of Ludwigia L.; however, similar lacunate tissue in extant Decodon verticillatus (L.) Ell. is secondary (phellem) and this study shows this tissue to be homologous to that seen in the fossil Decodon J.F. Gmel. A complex rhytidome is described in the largest fossil axes. It is composed of alternating bands of 'phelloids' and bands of non-active phloem with lacunae. This complex aquatic rhytidome is currently unknown in other living or fossil taxa.
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Gajdanowicz, P., E. Michard, M. Sandmann, M. Rocha, L. G. G. Correa, S. J. Ramirez-Aguilar, J. L. Gomez-Porras, et al. "Potassium (K+) gradients serve as a mobile energy source in plant vascular tissues." Proceedings of the National Academy of Sciences 108, no. 2 (December 27, 2010): 864–69. http://dx.doi.org/10.1073/pnas.1009777108.
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Opsahl, Stephen, and Ronald Benner. "Early diagenesis of vascular plant tissues: Lignin and cutin decomposition and biogeochemical implications." Geochimica et Cosmochimica Acta 59, no. 23 (December 1995): 4889–904. http://dx.doi.org/10.1016/0016-7037(95)00348-7.
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Heyes, Julian A., and Christopher J. Clark. "Magnetic resonance imaging of water movement through asparagus." Functional Plant Biology 30, no. 11 (2003): 1089. http://dx.doi.org/10.1071/fp03096.
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Asparagus spears are rapidly growing structures supplied with abundant vascular bundles. After extended periods of water loss, the stem surface becomes flaccid over a core of turgid tissue. We have used magnetic resonance imaging (MRI) coupled with a paramagnetic contrast reagent (Mn2+) to visualise water and ion movement within spear tissues. Using this technique we estimated the rate of water flow in the xylem and lateral movement out of the xylem into the surrounding tissues. Longitudinal flow rates of at least 3.7 mm min–1 and lateral diffusion rates of at least 17 μm min–1 were recorded. The outer parenchyma was difficult to label with vascular-supplied Mn2+, suggesting the presence of an apoplastic barrier. Stem shrinkage was greater in the outer parenchyma than in the inner cortex and pith parenchyma. Feeding the cut spear with 70 mM sucrose reduced the rate of lateral movement of Mn2+. The MRI technique highlighted differences in transport rates between adjacent vascular bundles and identified structural features with a resolution of 78 μm. This non-invasive technique is useful both for observing details of the transport paths in living tissue and for setting minimal estimates of transport rates.
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Dorchin, Netta, Amnon Freidberg, and Roni Aloni. "Morphogenesis of stem gall tissues induced by larvae of two cecidomyiid species (Diptera: Cecidomyiidae) on Suaeda monoica (Chenopodiaceae)." Canadian Journal of Botany 80, no. 11 (November 1, 2002): 1141–50. http://dx.doi.org/10.1139/b02-104.
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Izeniola obesula Dorchin and Stefaniola defoliata Dorchin (Diptera: Cecidomyiidae: Lasiopterini) are monophagous gall midges each inducing a unique kind of gall on stems of the salt marsh plant Suaeda monoica Gmelin (Chenopodiaceae). The morphogenesis of these two types of galls was studied in relation to the life history of the midges as observed both in the field and the laboratory. Izeniola obesula larvae penetrate the pith parenchyma through the growing shoot apex, causing intensive cell proliferation and inducing differentiation of novel vascular tissues and a sclerenchyma sheath around their chambers. Vascular differentiation in this gall originates from the larval chamber, a phenomenon attributed to local stimulation by the larva. It is suggested that the sclerenchyma layer in these galls is also induced by insect activity. Stefaniola defoliata larvae penetrate the stem laterally and reside inside the primary phloem, causing proliferation of phloem parenchyma, and are later encapsulated by secondary xylem tissue. Both galls are associated with a symbiotic fungus that grows along the inner walls of the larval chambers. The possible hormonal mechanisms controlling morphogenesis of the galls are discussed.Key words: gall morphogenesis, phytohormones, sclerenchyma, vascular differentiation.
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Williams, Christopher J., Joseph B. Yavitt, R. Kelman Wieder, and Natalie L. Cleavitt. "Cupric oxide oxidation products of northern peat and peat-forming plants." Canadian Journal of Botany 76, no. 1 (January 1, 1998): 51–62. http://dx.doi.org/10.1139/b97-150.
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Alkaline cupric oxide oxidation and proximate analysis were used to investigate the sources and diagenetic state of organic matter in six Sphagnum-dominated peatlands located between Alberta, Canada, and Ohio, U.S.A. Cupric oxide oxidation was also used to characterize vascular and nonvascular wetland plant species to provide a specific biological fingerprint of these plant tissues. Oxidation of 15 species of Sphagnum moss released large quantities of unsubstituted p-hydroxyl phenolic compounds as well as the species specific sphagnum acid (p-hydroxy-β-[carboxymethyl]-cinnamic acid). By contrast, vascular plant tissues released large amounts of lignin oxidation products. Cupric oxide oxidation of Sphagnum peat from more northerly sites produced mainly p-hydroxyl phenolic monomers with lesser amounts of vascular lignin derived phenols. In contrast, southern sites and those dominated by woody vegetation produced oxidation products characteristic of vascular plant lignin. A distinct relationship exists between the amount of acid-insoluble Klason lignin and both the diagenetically sensitive phenolic acid to aldehyde ratios as well as the total yield of vanillyl phenolic oxidation products. We found evidence of selective decay of phenolic lignin precursors. These relationships indicate the lignin component in surficial layers of Sphagnum-dominated peat is influenced by both Sphagnum and vascular plant lignin, and the structure of lignin appears to undergo diagenetic changes in these layers. Application of an end-member mixing model revealed that lignin oxidation products poorly predicted vegetational composition of the lignin in more decomposed peat, probably as a result of selective decay of lignin structural phenols. Key words: lignin, organic soil, proximate analysis, Sphagnum moss, wetland.
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Aloni, R. "The Role of Cytokinin in Organised Differentiation of Vascular Tissues." Functional Plant Biology 20, no. 5 (1993): 601. http://dx.doi.org/10.1071/pp9930601.
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The role of cytokinin as a limiting and controlling factor in the differentiation of vascular tissues in the plant body is discussed. Cytokinin controls the early stages of fibre differentiation in Helianthus stems and the regeneration of vessels and sieve tubes around a wound in Coleus internodes. The influence of cytokinin on cell differentiation in the vascular tissues varies according to its physiological levels and the levels of auxin. Cytokinin induces an acropetal polar pattern of vessel regeneration around a wound in internodes of Coleus. Similarly, adventitious roots induce acropetal polar patterns of vessel maturation in hypocotyls of Cucurbita. Cytokinin increases the sensitivity of the vascular cambium to the auxin stimulation, resulting in the highest ratio of phloem/xylem under the optimal level of cytokinin. High levels of cytokinin promote callose production on sieve plates. Studies of transgenic plants with altered levels of cytokinin (overexpressing the ipt gene) confirm the involvement of cytokinin in vascular differentiation.
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Knight, Noel L., and Mark W. Sutherland. "Histopathological Assessment of Fusarium pseudograminearum Colonization of Cereal Culms During Crown Rot Infections." Plant Disease 100, no. 2 (February 2016): 252–59. http://dx.doi.org/10.1094/pdis-04-15-0476-re.
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Histopathological assessment of the crown rot pathogen Fusarium pseudograminearum was performed using fluorescence microscopy of culm tissues of six cereal genotypes grown in inoculated field conditions. Tissue samples were collected at 10, 16, and 22 weeks after planting (WAP). Colonization of culm tissues was initiated through epidermal penetration, most distinctly through stomatal apertures, and progressed into the parenchymatous hypoderm, which exhibited the discoloration used as the basis for visual assessment of disease. Hyphae spread from the culm base vertically through the tissues, initially via the hypoderm and pith cavity. Colonization of sclerified cells occurred later in the disease process. Both xylem and phloem tissues became colonized by 16 WAP in all host genotypes, with colonization being less extensive in the more resistant genotypes. Culms displaying dead head symptoms revealed dense colonization in at least the first three internodes, with frequent xylem vessel and phloem cell occlusions. Paired living culms from the same plants exhibited less extensive colonization. These observations have revealed the ability of F. pseudograminearum to colonize all cell types of nodal and internodal sections, including vascular tissues, across all host genotypes. This study is the first detailed examination of the pattern of F. pseudograminearum colonization in adult hosts and indicates a potential vascular mechanism by which the effects of crown rot are produced.
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Roth, Anita, and Volker Mosbrugger. "Numerical studies of water conduction in land plants: evolution of early stele types." Paleobiology 22, no. 3 (1996): 411–21. http://dx.doi.org/10.1017/s0094837300016365.
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During land plant evolution, a change in stelar architecture, i.e., in the geometric arrangement of the water-conducting tissue inside the plant axis, can be observed. In the most primitive stele type, the protostele, the vascular tissue is organized as a simple central strand. Further evolutionary changes led to more peripherally arranged vascular tissues. In the siphonostele, for example, the vascular tissue forms a hollow cylinder filled with pith. A functional explanation of this early stelar evolution is provided in the present paper. Using a numerical simulation approach, we analyze the water transport properties of various protostelic and siphonostelic model axes. The results indicate that several geometric parameters are relevant for understanding the water transport properties of various stele types and for explaining the early stelar evolution: the parenchymatic path lengths (i.e., the distance between the xylem surface and the transpiring plant surface), the ratio of xylem surface over transpiring surface, and the ratio of cross-sectional area of xylem to cross-sectional area of the parenchyma outside of the xylem. As a whole, the evolution of early stele types may be viewed as a size-related multi-criteria optimization process in which the xylem volume as well as the fluid pressure gradients in the parenchyma and in the xylem are minimized. For slender plant axes, a protostele appears to be the optimal stelar architecture. In wider plant axes, however, other stelar architectures (such as a siphonostele) prove to be more efficient than a protostele.
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Decombeix, Anne-Laure, Anaïs Boura, and Alexandru M. F. Tomescu. "Plant hydraulic architecture through time: lessons and questions on the evolution of vascular systems." IAWA Journal 40, no. 3 (July 2019): 387–420. http://dx.doi.org/10.1163/22941932-40190254.
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ABSTRACTStudies of anatomically preserved fossils provide a wealth of information on the evolution of plant vascular systems through time, from the oldest evidence of vascular plants more than 400 million years ago to the rise of the modern angiosperm-dominated flora. In reviewing the key contributions of the fossil record, we discuss knowledge gaps and major outstanding questions about the processes attending the evolution of vascular systems. The appearance and diversification of early vascular plants in the late Silurian-Devonian was accompanied by the evolution of different types of tracheids, which initially improved the hydraulics of conduction but had less of an effect on mechanical support. This was followed in the Devonian and Carboniferous by an increase in complexity of the organization of primary vascular tissues, with different types of steles evolving in response to mechanical, hydraulic, and developmental regulatory constraints. Concurrently, secondary vascular tissues, such as wood, produced by unifacial or bifacial cambia are documented in a wide array of plant groups, including some that do not undergo secondary growth today. While wood production has traditionally been thought to have evolved independently in different lineages, accumulating evidence suggests that this taxonomic breadth reflects mosaic deployment of basic developmental mechanisms, some of which are derived by common ancestry. For most of vascular plant history, wood contained a single type of conducting element: tracheids (homoxyly). However, quantitative (e.g. diameter and length) and qualitative (e.g. pitting type) diversity of these tracheids allowed various taxa to cover a broad range of hydraulic properties. A second type of conducting elements, vessels, is first documented in an extinct late Permian (c. 260 Ma) group. While the putative hydraulic advantages of vessels are still debated, wood characterized by presence of vessels (heteroxyly) would become the dominant type, following the diversification of angiosperms during the Cretaceous.
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Liu, Shiang-Lin, Wei Siao, and Shu-Jen Wang. "Changing sink demand of developing shoot affects transitory starch biosynthesis in embryonic tissues of germinating rice seeds." Seed Science Research 20, no. 3 (April 29, 2010): 137–44. http://dx.doi.org/10.1017/s0960258510000115.
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AbstractThe mechanism of starch metabolism in the endosperm of germinating rice (Oryza sativaL.) seed (caryopsis) has been well studied; however, little is known about the occurrence and function of transitory starch in germinating rice embryos. During rice seed germination and seedling establishment, starch in the endosperm is hydrolysed to glucose, which is taken up by scutellar epithelial cells, converted to sucrose, and transported through vascular bundles to other embryonic tissues, such as growing shoots and roots. In this study, we found that soluble sugar was converted to starch in the scutellum 6 d after imbibition (DAI). Starch appeared primarily in cells surrounding the vascular bundles of the embryonic axis 12 DAI. The removal of growing shoots caused hyper-accumulation of starch in embryonic tissues, including the scutellum. In contrast, placing seedlings in the dark, which reduced photosynthetic efficiency, lowered starch levels in the embryonic axis cells. The disappearance of transitory starch from embryonic tissues of dark-grown seedlings was accompanied by a reduction of soluble sugar content and the down-regulation of the expression and activity of starch biosynthesis enzymes. These results suggest that the amount of transitory starch in embryonic tissues was dependent on the demand of growing sink tissues.
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Whittier, Dean P. "Induced apogamy in Tmesipteris (Psilotaceae)." Canadian Journal of Botany 82, no. 6 (June 1, 2004): 721–25. http://dx.doi.org/10.1139/b04-049.
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Gametophytes of Tmesipteris lanceolata Dang., which are mycorrhizal in nature, were grown in axenic culture. If cultured in the light on a nutrient medium containing minerals and 0.5% glucose, they did not become photosynthetic; however, about 15% of them produced apogamous sporophytes with stems and microphylls. The gametophytesporophyte junction had a direct connection between the gametophyte and sporophyte tissues and lacked a foot, which is typical for apogamy. Gametangia were limited to the gametophyte portions of these gametophytesporophyte growths, and the vascular tissue was present only in the sporophyte regions. The apogamous aerial stems had the normal anatomy for a sporophyte, with vascular tissue, epidermal cells, stomata, and chlorenchyma. The origin of the apogamous sporophytes was different from the origin in fern gametophytes. The Tmesipteris sporophytes arose terminally from the gametophyte apices. It appears that the apical meristem of the gametophyte is converted to a shoot apical meristem to form the apogamous aerial shoot.Key words: Tmesipteris, Psilotaceae, apogamy, sporophyte, gametophyte.
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Krüger, H., A. Viljoen, and P. S. Van Wyk. "Histopathology of Albugo tragopogonis on stems and petioles of sunflower." Canadian Journal of Botany 77, no. 1 (June 1, 1999): 175–78. http://dx.doi.org/10.1139/b99-016.
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Stem lesions in sunflower caused by Albugo tragopogonis (Pers.) S.F. Gray developed individually from primary infections and did not result from a systemic infection. Cell division and callose formation were not observed, but weak lignin deposition occurred in infected tissues. Hyphae occurred intercellularly in stems in the cortex, cambium, vascular rays, and pith. In petioles parenchymatous tissue was heavily colonized in contrast to lightly colonized collenchymatous hypodermis. The middle lamellae of cells in infected tissue were dissolved, and cells degenerated and eventually collapsed. Stem infections lead to deterioration of tissue integrity, weakening of stems, and finally to lodging of stems (breaking over).Key words: Albugo tragopogonis, Helianthus annuus, histopathology, stem lodging.
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Kenrick, Paul. "Changing expressions: a hypothesis for the origin of the vascular plant life cycle." Philosophical Transactions of the Royal Society B: Biological Sciences 373, no. 1739 (December 18, 2017): 20170149. http://dx.doi.org/10.1098/rstb.2017.0149.
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Plant life cycles underwent fundamental changes during the initial colonization of the land in the Early Palaeozoic, shaping the direction of evolution. Fossils reveal unanticipated diversity, including new variants of meiotic cell division and leafless gametophytes with mycorrhizal-like symbioses, rhizoids, vascular tissues and stomata. Exceptional fossils from the 407-Ma Rhynie chert (Scotland) play a key role in unlocking this diversity. These fossils are reviewed against progress in our understanding of the plant tree of life and recent advances in developmental genetics. Combining data from different sources sheds light on a switch in life cycle that gave rise to the vascular plants. One crucial step was the establishment of a free-living sporophyte from one that was an obligate matrotroph borne on the gametophyte. It is proposed that this difficult evolutionary transition was achieved through expansion of gene expression primarily from the gametophyte to the sporophyte, establishing a now extinct life cycle variant that was more isomorphic than heteromorphic. These changes also linked for the first time in one developmental system rhizoids, vascular tissues and stomata, putting in place the critical components that regulate transpiration and forming a physiological platform of primary importance to the diversification of vascular plants. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.
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Rudall, Paula. "Laticifers in Vascular Cambium and Wood of Croton Spp. (Euphorbiaceae)." IAWA Journal 10, no. 4 (1989): 379–83. http://dx.doi.org/10.1163/22941932-90001127.
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Laticifers are recorded both penetrating from primary tissues into the vascular cambium and secondary xylem, and traversing the secondary xylem in young stems of various Croton spp. These observations are unique for Euphorbiaceae, and highly unusual in other families. They indicate that laticifers in some instances enter the secondary xylem from the cortex, and in others become enveloped in secondary xylem following secondary meristematic activity by the vascular cambium.
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Flessner, Michael L., Roland R. Dute, and J. Scott McElroy. "Anatomical Response of St. Augustinegrass to Aminocyclopyrachlor Treatment." Weed Science 59, no. 2 (June 2011): 263–69. http://dx.doi.org/10.1614/ws-d-10-00116.1.
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Aminocyclopyrachlor (AMCP) is a synthetic auxin herbicide that controls primarily broadleaf (eudicotyledonous) weeds. Previous research indicates that St. Augustinegrass is unacceptably injured by AMCP. In light of the fact that synthetic auxin herbicides usually are safe when applied to monocotyledons, the mechanism for this injury is not fully understood. Anatomical response of St. Augustinegrass to AMCP was investigated using light microscopy. Apical meristem node tissue responded with callus tissue proliferation, abnormal location and development of the apical meristem, necrosis of the developing vascular tissue, vascular parenchyma proliferation, and xylem gum blockages. Node tissues away from the apical meristem responded with xylem gum blockages and the stimulation of lateral meristems and adventitious root formation. Root tip response to AMCP treatment was characterized by a loss of organization. Root tip apical meristem and vascular tissue maturation was disorganized. Additionally, lateral root generation occurred abnormally close to the root tip. These responses impair affected tissue functionality. Mature tissue was unaffected by AMCP treatment. All of these responses are characteristic of synthetic auxin herbicide treatment to other susceptible species. This research indicates that AMCP treatment results in St. Augustinegrass injury and subsequent death through deleterious growth stimulation and concomitant vascular inhibition.
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Nayer, B. K. "Evolution of a cormophytic plant body in lower vascular plants." Journal of Palaeosciences 41 (December 31, 1992): 75–86. http://dx.doi.org/10.54991/jop.1992.1108.
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Possession of a cormophytic plant body and stelar system distinguishes vascular plants from thallophytic ancestors. Based on morphology and development of sporophyte and gametophyte of pteridophytes it is argued that current interpretations of morphology and evolution of these features in terms of Axial theory and Stelar theory are untenable in these primitive vascular plants. The leaf, and not the axis/stem, is the primary organ and the first to evolve. The leaf along with its associated root constitutes a Phyllorhize which is the basic unit of construction of the plant body. Shoot apical meristem functions only in initiating leaves and branches and what appears as stem is a product of conjoined leaf bases, the shoot meristem contributing little to its construction. Vasculature is developed only in tissues derived from leaf and root meristems; no vasculature is developed in tissue derived from the shoot meristem. Stelar cylinder consists of secondarily interconnected basal regions of leaf vasculatures and sometimes also vasculature of leaf-associated roots. The pattern of growth (different in taxa having erect rhizome and plagiotropic rhizome) determines the nature of the stelar cylinder. Evolution apparently followed the same course in gametophytic and sporophytic generations, and evolution of pteridophyte gametophyte indicates that the primitive form was an amorphous cushion shaped thallus devoid of meristem and vasculature. It is shown how a phyllorhize unit evolved from such a plant body. Morphological, anatomical and ontogenetic evidences are presented in support of the contention that the pteridophyte plant body is formed of conjoined leaf bases and its stele is the product of leaf base vasculatures interconnected in a regular pattern. Also, it is shown that stelar evolution did not follow the sequence suggested by Stelar theory.
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Lin, Bai-Ling, and V. Raghavan. "Lateral root initiation in Marsilea quadrifolia. I. Origin and histogenesis of lateral roots." Canadian Journal of Botany 69, no. 1 (January 1, 1991): 123–35. http://dx.doi.org/10.1139/b91-018.
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In Marsilea quadrifolia, lateral roots arise from modified single cells of the endodermis located opposite the protoxylem poles within the meristematic region of the parent root. The initial cell divides in four specific planes to establish a fivecelled lateral root primordium, with a tetrahedral apical cell in the centre and the oldest merophytes and the root cap along the sides. The cells of the merophyte divide in a precise pattern to give rise to the cells of the cortex, endodermis, pericycle, and vascular tissues of the emerging lateral root. Although the construction of the parent root is more complicated than that of lateral roots, patterns of cell division and tissue formation are similar in both types of roots, with the various tissues being arranged in similar positions in relation to the central axis. Vascular connection between the lateral root primordium and the parent root is derived from the pericycle cells lying between the former and the protoxylem members of the latter. It is proposed that the central axis of the root is not only a geometric centre, but also a physiological centre which determines the fate of the different cell types. Key words: lateral root initiation, Marsilea quadrifolia, root histogenesis.
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Keming, Cui, Lu Pengzhe, Liu Qinghua, and Li Zhengli. "Regeneration of Vascular Tissues in Broussonetia Papyrifera Stems After Removal of the Xylem." IAWA Journal 10, no. 2 (1989): 193–99. http://dx.doi.org/10.1163/22941932-90000488.
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The central cylinder of xylem plus pith was removed from the main stem of 1- to 2- year-old Broussonetia papyrifera (L.) Vent. treelets, leaving only the bark, cambial zone cells and a few immature xylem cells. The immature phloem and xylem cells and original cambium zone cells rapidly produced callus, then the original cambial zone started to produce xylem and phloem. A flat meristem was initiated intermittently inside the callus. Eventually, these islands connected laterally to form a ring of new cambium that began to produce normal xylem inward and phloem outward. About one month later, a concave oblate trunk had formed, which connected distally and proximally with the original trunk.
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Mensi, Imène, Marie-Stéphanie Vernerey, Daniel Gargani, Michel Nicole, and Philippe Rott. "Breaking dogmas: the plant vascular pathogen Xanthomonas albilineans is able to invade non-vascular tissues despite its reduced genome." Open Biology 4, no. 2 (February 2014): 130116. http://dx.doi.org/10.1098/rsob.130116.
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Xanthomonas albilineans , the causal agent of sugarcane leaf scald, is missing the Hrp type III secretion system that is used by many Gram-negative bacteria to colonize their host. Until now, this pathogen was considered as strictly limited to the xylem of sugarcane. We used confocal laser scanning microscopy, immunocytochemistry and transmission electron microscopy (TEM) to investigate the localization of X. albilineans in diseased sugarcane. Sugarcane plants were inoculated with strains of the pathogen labelled with a green fluorescent protein. Confocal microscopy observations of symptomatic leaves confirmed the presence of the pathogen in the protoxylem and metaxylem; however, X. albilineans was also observed in phloem, parenchyma and bulliform cells of the infected leaves. Similarly, vascular bundles of infected sugarcane stalks were invaded by X. albilineans . Surprisingly, the pathogen was also observed in apparently intact storage cells of the stalk and in intercellular spaces between these cells. Most of these observations made by confocal microscopy were confirmed by TEM. The pathogen exits the xylem following cell wall and middle lamellae degradation, thus creating openings to reach parenchyma cells. This is the first description of a plant pathogenic vascular bacterium invading apparently intact non-vascular plant tissues and multiplying in parenchyma cells.
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Barka, E. Aït, J. C. Audran, O. Brun, C. Leddet, and J. Dereuddre. "Formation et distribution de glace dans les bourgeons de Vitis vinifera avant et au cours de leur débourrement." Canadian Journal of Botany 73, no. 12 (December 1, 1995): 1878–88. http://dx.doi.org/10.1139/b95-200.
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Evolution of the exothermic profile of latent buds of Vitis vinifera L. cv. Pinot noir was followed using differential scanning microcalorimetry. Analyses performed on buds at the winterized state (stage 1), on wolly buds (stage 3), and on green pointing buds (stage 5) showed that modes and speed of extracellular and intracellular liquid crystallisation vary according to the phenological stage and are closely linked to the meristematic tissues. Among these, the vascular system plays a major role in the crystallisation process. Indeed, within the winterized buds, where it is at the procambial stage, i.e. nonfunctional, it forms a barrier to the propagation of ice toward the apical part of the bud where water remains in a prolongated surfusion state. On the opposite, during the period preceeding bud opening, from stage 3 to stage 5, where its differentiation leads to a continuous and functional vascular system connecting the bud base to its apical part, it forms a preferred path allowing rapid ice propagation, leading to a violent ice setting in all the tissues. Key words: latent bud, exotherm, calorimetry, vascular system, wine. [Journal translation]
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Tenorio Berrío, Rubén, Kevin Verstaen, Niels Vandamme, Julie Pevernagie, Ignacio Achon, Julie Van Duyse, Gert Van Isterdael, et al. "Single-cell transcriptomics sheds light on the identity and metabolism of developing leaf cells." Plant Physiology 188, no. 2 (October 23, 2021): 898–918. http://dx.doi.org/10.1093/plphys/kiab489.
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Abstract As the main photosynthetic instruments of vascular plants, leaves are crucial and complex plant organs. A strict organization of leaf mesophyll and epidermal cell layers orchestrates photosynthesis and gas exchange. In addition, water and nutrients for leaf growth are transported through the vascular tissue. To establish the single-cell transcriptomic landscape of these different leaf tissues, we performed high-throughput transcriptome sequencing of individual cells isolated from young leaves of Arabidopsis (Arabidopsis thaliana) seedlings grown in two different environmental conditions. The detection of approximately 19,000 different transcripts in over 1,800 high-quality leaf cells revealed 14 cell populations composing the young, differentiating leaf. Besides the cell populations comprising the core leaf tissues, we identified subpopulations with a distinct identity or metabolic activity. In addition, we proposed cell-type-specific markers for each of these populations. Finally, an intuitive web tool allows for browsing the presented dataset. Our data present insights on how the different cell populations constituting a developing leaf are connected via developmental, metabolic, or stress-related trajectories.
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Bhatia, Naveen P., Kerry B. Walsh, Ivo Orlic, Rainer Siegele, Nanjappa Ashwath, and Alan J. M. Baker. "Studies on spatial distribution of nickel in leaves and stems of the metal hyperaccumulator Stackhousia tryonii Bailey using nuclear microprobe (micro-PIXE) and EDXS techniques." Functional Plant Biology 31, no. 11 (2004): 1061. http://dx.doi.org/10.1071/fp03192.
Full textAbstract:
Stackhousia tryonii Bailey is one of the three nickel hyperaccumulators reported from Australia. It is a rare, herbaceous plant that accumulates (Ni) both in leaf and stem tissues. Localisation of Ni in leaf and stem tissues of S. tryonii was studied using two micro-analytical techniques, energy dispersive X-ray spectrometry (EDXS) and micro-proton-induced X-ray emission spectrometry (micro-PIXE). Dimethylglyoxime complexation of Ni was also visualised by bright- and dark-field microscopy, but this technique was considered to create artefacts in the distribution of Ni. Energy dispersive X-ray spectrometric analysis indicated that guard cells possessed a lower Ni concentration than epidermal cells, and that epidermal cells and vascular tissue contained higher levels of Ni than mesophyll, as reported for other Ni hyperaccumulators. The highest Ni concentration was recorded (PIXE quantitative point analysis) in the epidermal cells and vascular tissue (5400 μg g–1 DW), approximately double that recorded in palisade cells (2500 μg g–1 DW). However, concentrations were variable within these tissues, explaining, in part, the similarity between average Ni concentrations of these tissues (as estimated by region selection mode). Stem tissues showed a similar distribution pattern as leaves, with relatively low Ni concentration in the pith (central) region. The majority of Ni (73–85% for leaves; 80–92% for stem) was extracted from freeze-dried sections by water extraction, suggesting that this metal is present in a highly soluble and mobile form in the leaf and stem tissues of S. tryonii.