vascular

Examples of vascular in the following topics:

• Seedless Vascular Plants

  • Seedless vascular plants, which reproduce and spread through spores, are plants that contain vascular tissue, but do not flower or seed.
  • The vascular plants, or tracheophytes, are the dominant and most conspicuous group of land plants.
  • By the late Devonian period, plants had evolved vascular tissue, well-defined leaves, and root systems.
  • Seedless vascular plants are plants that contain vascular tissue, but do not produce flowers or seeds.
  • In seedless vascular plants, such as ferns and horsetails, the plants reproduce using haploid, unicellular spores instead of seeds.

• The Major Divisions of Land Plants

  • Land plants, or embryophytes, are classified by the presence or absence of vascular tissue and how they reproduce (with or without seeds).
  • Plants that lack vascular tissue, which is formed of specialized cells for the transport of water and nutrients, are referred to as non-vascular plants or bryophytes.
  • Non-vascular embryophytes probably appeared early in land plant evolution and are all seedless.
  • Lycophytes and pterophytes are both referred to as seedless vascular plants because they do not produce any seeds.
  • Land plants are categorized by presence or absence of vascular tissue and their reproduction with or without the use of seeds.

• Vascular Spasm

  • The vasoconstriction response is triggered by factors such as a direct injury to vascular smooth muscle, signaling molecules released by injured endothelial cells and activated platelets (such as thromboxane A2), and nervous system reflexes initiated by local pain receptors.
  • Vascular spasm is much more effective at slowing the flow of blood in smaller blood vessels.
  • During inflammation, vasodilation occur, along with increased vascular permeability and leukocyte chemotaxis, ending the spasm of vasoconstriction and hemostasis as wound healing begins.

• Vascular Tissue: Xylem and Phloem

  • Xylem and phloem form the vascular system of plants to transport water and other substances throughout the plant.
  • The first fossils that show the presence of vascular tissue date to the Silurian period, about 430 million years ago.
  • Together, xylem and phloem tissues form the vascular system of plants .

• Stem Anatomy

  • The xylem and phloem that make up the vascular tissue of the stem are arranged in distinct strands called vascular bundles, which run up and down the length of the stem.
  • In monocot stems, the vascular bundles are randomly scattered throughout the ground tissue .
  • The ground tissue towards the interior of the vascular tissue in a stem or root is known as pith, while the layer of tissue between the vascular tissue and the epidermis is known as the cortex .
  • Sclerenchyma fibers cap the vascular bundles.
  • Summarize the roles of dermal tissue, vascular tissue, and ground tissue

• Bryophytes

  • Bryophytes (liverworts, mosses, and hornworts) are non-vascular plants that appeared on earth over 450 million years ago.
  • By the Silurian period, however, vascular plants had spread through the continents.
  • This compelling fact is used as evidence that non-vascular plants must have preceded the Silurian period.
  • Although the term non-tracheophyte is more accurate, bryophytes are commonly called non-vascular plants.

• Ferns and Other Seedless Vascular Plants

  • Ferns, club mosses, horsetails, and whisk ferns are seedless vascular plants that reproduce with spores and are found in moist environments.
  • Water is required for fertilization of seedless vascular plants; most favor a moist environment.
  • The club mosses, or phylum Lycopodiophyta, are the earliest group of seedless vascular plants.
  • With their large fronds, ferns are the most-readily recognizable seedless vascular plants.
  • They are considered the most-advanced seedless vascular plants and display characteristics commonly observed in seed plants.

• Plant Tissues and Organ Systems

  • They differentiate into three main types: dermal, vascular, and ground tissue.
  • Vascular tissue is an example of a complex tissue.
  • In stems, the xylem and the phloem form a structure called a vascular bundle ; in roots, this is termed the vascular stele or vascular cylinder.
  • Vascular plants have two distinct organ systems: a shoot system and a root system .
  • The vascular bundles are encased in ground tissue and surrounded by dermal tissue.

• Evolution of Land Plants

  • Embryo protection developed prior to the development of vascular plants which, in turn, evolved before seed plants and flowering plants.
  • The oldest-known vascular plants have been identified in deposits from the Devonian.
  • One of the richest sources of information is the Rhynie chert, a sedimentary rock deposit found in Rhynie, Scotland, where embedded fossils of some of the earliest vascular plants have been identified .
  • From the recovered specimens, it is not possible to establish for certain whether Cooksonia possessed vascular tissues.
  • This Rhynie chert contains fossilized material from vascular plants.

• Phylum Echinodermata

  • Echinoderms are invertebrates that have pentaradial symmetry, a spiny skin, a water vascular system, and a simple nervous system.
  • These animals possess a true coelom that is modified into a unique circulatory system called a water vascular system.
  • The water vascular system also projects from holes in the skeleton in the form of tube feet.
  • The madreporite is a light-colored, calcerous opening used to filter water into the water vascular system of echinoderms.
  • By moving water through the unique water vascular system, the echinoderm can move and force open mollusk shells during feeding.