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    Stem Leaves

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    MerrylFrancisco
    The document summarizes key features of herbaceous and woody plant stems. Herbaceous plants have soft, flexible stems that exhibit primary growth and are typically annual. Woody plants have hard, thickened stems that exhibit both primary and secondary growth and are typically perennial. The document describes stem structures like nodes, internodes, buds, and vascular tissue and how stems develop primary and secondary growth.

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    Stem Leaves

    Uploaded by

    MerrylFrancisco
    135 views20 pages
    The document summarizes key features of herbaceous and woody plant stems. Herbaceous plants have soft, flexible stems that exhibit primary growth and are typically annual. Woody plants have hard, thickened stems that exhibit both primary and secondary growth and are typically perennial. The document describes stem structures like nodes, internodes, buds, and vascular tissue and how stems develop primary and secondary growth.

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    The document summarizes key features of herbaceous and woody plant stems. Herbaceous plants have soft, flexible stems that exhibit primary growth and are typically annual. Woody plants have hard, thickened stems that exhibit both primary and secondary growth and are typically perennial. The document describes stem structures like nodes, internodes, buds, and vascular tissue and how stems develop primary and secondary growth.

    Copyright:

    © All Rights Reserved
    Download as PPTX, PDF, TXT or read online from Scribd
    Download as pptx, pdf, or txt
    135 views20 pages

    Stem Leaves

    Uploaded by

    MerrylFrancisco
    The document summarizes key features of herbaceous and woody plant stems. Herbaceous plants have soft, flexible stems that exhibit primary growth and are typically annual. Woody plants have hard, thickened stems that exhibit both primary and secondary growth and are typically perennial. The document describes stem structures like nodes, internodes, buds, and vascular tissue and how stems develop primary and secondary growth.

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    Stems

    Herbaceous Plants

    • Soft-bodied plants with flexible stems.


    • Most are annual (live only one year).
    • Exhibit primary growth.
    – e.g. lettuce, beans, grasses
    Woody Plants
    • Plants with hard,
    thickened, woody stems
    • Most are perennial (live
    many years)
    • Exhibit primary and
    secondary growth
    – e.g. trees, bushes
     Terminal bud- located at the tip of
    the stem/twig
     Axillary/ lateral bud- along the side
    of the stem
     Node- a point on a stem which from
    which a leaf or bud grows
     Internode - the length of stem
    between two successive nodes
     LENTICELS- Tiny raised pores
    for gaseous exchange

     LEAF SCARS- they are the places


    at which the leaf stalks grew from the
    stem

     BUDLE SCARS- appears dot in the leaf


    scars

     BUD SCARS- Ring of small narrow


    scars left by the falling away of the bud
    scales and forming a complete thin
    circle around a twig
    Typical Stem Cross Section
    Helianthus annuus-
    sun flower annual
    Epidermis

    Cortex

    A ring of vascular bundles

    Pith
    Stems:
    Epidermis
    • In herbaceous plants
    and young woody
    plants, the stem is
    covered with
    epidermis.
    • Epidermis secretes
    cuticle, has stomata,
    and may be
    photosynthetic.
    Stems:
    Cortex and Pith
    • Cortex layer
    contains
    parenchyma cells
    and vascular
    bundles.
    • Pith makes up the
    center of the stem,
    and is absent in
    hollow stems.
    Stems:
    Vascular Tissue
    • Vascular bundles are
    in the cortex.
    • While primary xylem
    and phloem are made
    by the apical
    meristem, secondary
    xylem and phloem
    come from the
    vascular cambium,
    another meristem
    Trunk:
    Primary Growth

    • Primary Growth is
    primarily vertical.

    • This kind of growth


    gives the plant its
    height.
    Trunk:
    Secondary Growth
    • Secondary growth is
    seen in woody plants.
    • This kind of growth
    produces stronger,
    thicker stems from
    the vascular cambium
    and cork cambium.
    • Horizontal Growth
    Cross section of
    young stem with
    secondary growth
    Wood and Bark
    • Xylem makes up
    the wood of trees
    and shrubs.
    • Live phloem cells
    form the green
    bark.
    • Dead cork cells
    make up the bark.
    Annual Rings
    • Trees in temperate zones
    grow at different rates in
    different seasons,
    causing annual rings to
    form.
    • In some parts of the
    tropics, if seasons vary
    little, tree rings are
    indistinct.
    LEAVES

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