The dermal tissue covers the outer surface of the stem and usually functions to waterproof, protect and control gas exchange. Stem usually consist of three tissues, dermal tissue, ground tissue and vascular tissue. Ep = epidermis C = cortex BF = bast fibres P = phloem X = xylem Pi = pith Woody: hard textured stems with secondary xylem.įlax stem cross-section, showing locations of underlying tissues.Tuber: a swollen, underground storage stem adapted for storage and reproduction, e.g.Thorn: a modified stem with a sharpened point.Stolon: a horizontal stem that produces rooted plantlets at its nodes and ends, forming near the surface of the ground.Scape: a stem that holds flowers that comes out of the ground and has no normal leaves.Runner: a type of stolon, horizontally growing on top of the ground and rooting at the nodes, aids in reproduction.Rhizome: a horizontal underground stem that functions mainly in reproduction but also in storage, e.g.Pseudostem: a false stem made of the rolled bases of leaves, which may be 2 to 3 m (6 ft 7 in to 9 ft 10 in) tall, as in banana.Prickle: a sharpened extension of the stem's outer layers, e.g.Peduncle: a stem that supports an inflorescence.Pedicel: stems that serve as the stalk of an individual flower in an inflorescence or infrutescence.Node: a point of attachment of a leaf or a twig on the stem in seed plants.It possesses the ability to elongate, either from its base or from its extremity depending on the species. Internode: an interval between two successive nodes.Herbaceous: non woody, they die at the end of the growing season.Fruticose: stems that grow shrublike with woody like habit.Decumbent: stems that lie flat on the ground and turn upwards at the ends.Corm: a short enlarged underground, storage stem, e.g.Climbing: stems that cling or wrap around other plants or structures.Cladode (including phylloclade): a flattened stem that appears more-or-less leaf like and is specialized for photosynthesis, e.g.Caespitose: when stems grow in a tangled mass or clump or in low growing mats.Bulbs are a combination of stem and leaves so may better be considered as leaves because the leaves make up the greater part. Bulbs often function in reproduction by splitting to form new bulbs or producing small new bulbs termed bulblets. Bulb: a short vertical underground stem with fleshy storage leaves attached, e.g.Bud: an embryonic shoot with immature stem tip.Branched: aerial stems are described as being branched or unbranched.Axillary bud: a bud which grows at the point of attachment of an older leaf with the stem.Arborescent: tree with woody stems normally with a single trunk.Actually these stems are just extremely short, the leaves appearing to rise directly out of the ground, e.g. Acaulescent: used to describe stems in plants that appear to be stemless.Stems are often specialized for storage, asexual reproduction, protection, or photosynthesis, including the following: The two tissues are separated by cambium, a tissue that divides to form xylem or phloem cells. The phloem tissue consists of sieve tubes and their companion cells. The xylem tissue transports water by the action of transpiration pull, capillary action, and root pressure. Stems have two pipe-like tissues called xylem and phloem. Stems have cells called meristems that annually generate new living tissue. The normal lifespan of plant cells is one to three years. Transport of fluids between the roots and the shoots in the xylem and phloem (see below).The stems keep the leaves in the light and provide a place for the plant to keep its flowers and fruits. Support for and the elevation of leaves, flowers, and fruits.Stems have four main functions which are: In most plants stems are located above the soil surface but some plants have underground stems. The term " shoots" is often confused with "stems" "shoots" generally refers to new fresh plant growth including both stems and other structures like leaves or flowers. The internodes distance one node from another.Adventitious roots may also be produced from the nodes. The nodes hold one or more leaves, as well as buds which can grow into branches (with leaves, conifer cones, or flowers).The stem is normally divided into nodes and internodes: The stem can also be called halm or haulm or culms. It supports leaves, flowers and fruits, transports water and dissolved substances between the roots and the shoots in the xylem and phloem, stores nutrients, and produces new living tissue. This above-ground stem of Polygonum has lost its leaves, but is producing adventitious roots from the nodes.Ī stem is one of two main structural axes of a vascular plant, the other being the root.
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