1. Modeling the Hydrodynamics of Phloem Sieve Plates - PMC - NCBI
Sieve plates have an enormous impact on the efficiency of the phloem vascular system of plants, responsible for the distribution of photosynthetic products.
Sieve plates have an enormous impact on the efficiency of the phloem vascular system of plants, responsible for the distribution of photosynthetic products. These thin plates, which separate neighboring phloem cells, are perforated by a large number of ...
2. Sieve element occlusion (SEO) genes encode structural phloem proteins ...
25 Jun 2012 · The sieve element occlusion (SEO) gene family originally was delimited to genes encoding structural components of forisomes, ...
The sieve element occlusion (SEO) gene family originally was delimited to genes encoding structural components of forisomes, which are specialized crystalloid phloem proteins found solely in the Fabaceae. More recently, SEO genes discovered in various ...
3. Phloem: Cell Types, Structure, and Commercial Uses - IntechOpen
The sieve tube elements are distinguished by the presence of sieve plates ... Since the sieve tube element loses its nucleus and ribosomes, the companion cell ...
Phloem is the vascular tissue in charge of transport and distribution of the organic nutrients. The phloem is also a pathway to signaling molecules and has a structural function in the plant body. It is typically composed of three cell types: sieve elements, parenchyma, and sclerenchyma. The sieve elements have the main function of transport and typically have lost their nuclei and other organelles in the course of their specialization. Hence, the sieve elements rely on specialized neighboring parenchyma cells to sustain all of their physiological function and activities. All cell types of the phloem may vary morphologically and in their distribution in the tissue, and this diversity is taxonomic and functionally informative. The phloem can be of primary or secondary origin, being derived from either procambium or cambium, respectively. Some vascular plant lineages have exclusive primary phloem, such as the lycophytes, ferns, and the monocotyledons, and the sieve elements will be long living in these taxa. In plants with secondary growth, the secondary phloem is formed, and typically the primary phloem collapses. Because new secondary phloem is constantly formed, the longevity of sieve elements in the secondary plant body is much more reduced. In this chapter, the structure of the phloem and its cell types are described in detail and also some of the known commercial uses of this tissue.
4. P-proteins in Arabidopsis are heteromeric structures involved ... - Frontiers
10 Jun 2013 · Angiosperm sieve elements are characterized by abundant structural phloem proteins (P-proteins; Cronshaw and Esau, 1967), the identity and ...
Structural phloem proteins (P-proteins) are characteristic components of the sieve elements in all dicotyledonous and many monocotyledonous angiosperms. Tobacco P-proteins were recently confirmed to be encoded by the widespread sieve element occlusion (SEO) gene family, and tobacco SEO proteins were shown to be directly involved in sieve tube sealing thus preventing the loss of photosynthate. Analysis of the two Arabidopsis SEO proteins (AtSEOa and AtSEOb) indicated that the corresponding P-protein subunits do not act in a redundant manner. However, there are still pending questions regarding the interaction properties and specific functions of AtSEOa and AtSEOb as well as the general function of structural P-proteins in Arabidopsis. In this study, we characterized the Arabidopsis P-proteins in more detail. We used in planta bimolecular fluorescence complementation assays to confirm the predicted heteromeric interactions between AtSEOa and AtSEOb. Arabidopsis mutants depleted for one or both AtSEO proteins lacked the typical P-protein structures normally found in sieve elements, underlining the identity of AtSEO proteins as P-proteins and furthermore providing the means to determine the role of Arabidopsis P-proteins in sieve tube sealing. We therefore developed an assay based on phloem exudation. Mutants with reduced AtSEO expression levels lost twice as much photosynthate following injury as comparable wild-type plants, confirming that Arabidopsis P-proteins are indeed i...
5. Drought impacts on tree phloem: from cell-level responses to ecological ...
6 Feb 2019 · Modelling and theoretical studies suggest that parameters affecting phloem transport efficiency are phloem and xylem axial hydraulic ...
Abstract. On-going climate change is increasing the risk of drought stress across large areas worldwide. Such drought events decrease ecosystem productivity and
6. [PDF] Reversible Calcium-Regulated Stopcocks in Legume Sieve Tubes
100-fold higher than it is in typical plant cells (Brauer et al.,. 1998). ... Transient increase of intra- cellular Ca2 during excitation of tonoplast-free Chara ...
7. geometry of the forisome–sieve element–sieve plate complex in the ...
The sieve elements in the phloem of higher plants are highly differentiated cells forming the syncytial sieve tube network that accomplishes the distribution of ...
Abstract. Forisomes are contractile protein bodies that appear to control flux rates in the phloem of faboid legumes by reversibly plugging the sieve tubes. Plu
8. Angiosperm - Ground Tissue, Photosynthesis, Vascular System
Parenchyma cells are interspersed throughout. Sieve elements are longitudinal cells that transport food. They are composed of sieve cells and sieve-tube members ...
Angiosperm - Ground Tissue, Photosynthesis, Vascular System: The ground tissue system consists of three simple tissues: parenchyma, collenchyma, and sclerenchyma. Water and nutrients flow through conductive tissues (xylem and phloem) in plants just as the bloodstream distributes nutrients throughout the bodies of animals.
9. Plant Structures | Biology for Majors II - Lumen Learning
Meristematic tissues consist of three types, based on their location in the plant. Apical meristems contain meristematic tissue located at the tips of stems and ...
While individual plant species are unique, all share a common structure: a plant body consisting of stems, roots, and leaves. They all transport water, minerals, and sugars produced through photosynthesis through the plant body in a similar manner. All plant species also respond to environmental factors, such as light, gravity, competition, temperature, and predation.
10. [PDF] SAMPLE PREPARATION FUNDAMENTALS FOR ... - Agilent
The variable tip spacing feature of multiple probe liquid handlers allows them to expand their tip-to- tip width to aspirate from various test tube sizes ...
11. [PDF] Light on phloem transport - (an MRI approach) - WUR eDepot
20 Oct 2016 · sieve tubes allowed for an increased amount of phloem sap to be transported while the phloem flow velocity to remain effectively constant.
12. what characteristic of sieve-tube members allow them to efficiently ...
13 hours ago · Figure (PageIndex11) Phloem transports sugars and other items. In angiosperms sieve-tube elements contain the sugar solution. Sieve-tube ...
Posted On 2023-10-16
13. Diversity of funnel plasmodesmata in angiosperms - bioRxiv
5 May 2021 · In most plant tissues, threads of cytoplasm, or plasmodesmata, connect the protoplasts via pores in the cell walls. This enables symplasmic ...
In most plant tissues, threads of cytoplasm, or plasmodesmata, connect the protoplasts via pores in the cell walls. This enables symplasmic transport, for instance in phloem loading, transport, and unloading. Importantly, the geometry of the wall pore limits the size of the particles that may be transported, and also (co-)defines plasmodesmal resistance to diffusion and convective flow. However, quantitative information on transport through plasmodesmata in non-cylindrical cell wall pores is scarce. We have found conical, funnel-shaped cell wall pores in the phloem-unloading zone in growing root tips of five eudicot and two monocot species, specifically between protophloem sieve elements and phloem pole pericycle cells. 3D reconstructions by electron tomography suggested that funnel plasmodesmata possess a desmotubule but lack tethers to fix it in a central position. Model calculations showed that both diffusive and hydraulic resistance decrease drastically in conical cell wall pores compared to cylindrical channels, even at very small opening angles. Notably, the effect on hydraulic resistance was relatively larger. We conclude that funnel plasmodesmata generally are present in specific cell-cell interfaces in angiosperm roots, where they appear to facilitate symplasmic phloem unloading. Interestingly, cytosolic sleeves of most plasmodesmata reported in the literature do not resemble straight annuli but possess variously shaped widenings. Our evaluations suggest that widenings too small for identification on electron micrographs may drastically reduce the hydraulic and diffusional resistance of these pores. Consequently, theoretical models assuming cylindrical symmetries will underestimate plasmodesmal conductivities. ### Competing Interest Statement The authors have declared no competing interest.
14. Phloem unloading in Arabidopsis roots is convective and regulated by ...
23 Feb 2017 · Solute flow occurs through sieve elements (SEs), elongated cells connected to each other by perforated end walls called sieve plates. During ...
A mechanism called photosynthesis allows plants to use energy from sunlight to make sugars from carbon dioxide gas and water. These sugars can then be used as fuel, or as building blocks for wood and other plant structures. Every part of the plant requires sugars, but most photosynthesis happens in the leaves and stems, so the sugars need to be able to move around the plant to wherever they are needed. Phloem tubes form a network that transports sugar, proteins and other molecules around the plant within a fluid known as sap. Because this network is so extensive, it is very difficult to study, which has left researchers with major questions about how it works. For example, it is not clear how the sugar and other molecules leave the phloem when they reach their destination. Ross-Elliot et al. used a combination of microscopy and mathematical modeling to investigate how sugars and other molecules leave the phloem in the roots of a plant called Arabidopsis thaliana. The experiments show that these molecules move directly into cells within a neighboring tissue called the phloem-pole pericycle via pores known as funnel plasmodesmata. Ross-Elliot et al. incorporated the experimental data into a mathematical model of phloem unloading. This model suggests that sugars and other small molecules move freely through the funnel plasmodesmata, but large proteins pass through these pores in pulses. Future challenges include finding out exactly how plants control phloem unloading and to investigate whether it is possible to modify the delivery of specific molecules to particular parts of the plant.
15. [PDF] 10644297.pdf - Enlighten Theses - University of Glasgow
as sieve elements was determined by cutting the cell types out from the ... the sieve-element side would permit a large increase in flow rate. On the ...
16. Sucrose transport inside the phloem: Bridging hydrodynamics and ...
14 Jun 2023 · In plants, the delivery of the products of photosynthesis is achieved through a hydraulic system labeled as phloem.
In plants, the delivery of the products of photosynthesis is achieved through a hydraulic system labeled as phloem. This semi-permeable plant tissue consists of
17. [PDF] Biology AS – Unit 1 - Bangor University
... increases the efficiency ... the sieve tube cells/elements. Sieve plates containing pores allows bidirectional flow from element to element throughout the plant.
18. [PDF] Answers - Pearson
human fat cell; X – transporting things, since the holes allow the flow of substances from one cell into another. This is in fact a phloem sieve cell, which ...