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tunicate : sessile chordate that is a member of Urochordata
https://openstax.org/books/biology/pages/29-key-terms
Urochordata : clade composed of tunicates
https://openstax.org/books/biology/pages/29-key-terms
Urodela : salamanders
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vertebral column : series of separate bones joined together as a backbone
https://openstax.org/books/biology/pages/29-key-terms
Vertebrata : members of the phylum Chordata that possess a backbone
https://openstax.org/books/biology/pages/29-key-terms
A vascular plant consists of two organ systems: the shoot system and the root system. The shoot system includes the aboveground vegetative portions (stems and leaves) and reproductive parts (flowers and fruits). The root system supports the plant and is usually underground. A plant is composed of two main types of tiss...
https://openstax.org/books/biology/pages/30-chapter-summary
The stem of a plant bears the leaves, flowers, and fruits. Stems are characterized by the presence of nodes (the points of attachment for leaves or branches) and internodes (regions between nodes).
https://openstax.org/books/biology/pages/30-chapter-summary
Plant organs are made up of simple and complex tissues. The stem has three tissue systems: dermal, vascular, and ground tissue. Dermal tissue is the outer covering of the plant. It contains epidermal cells, stomata, guard cells, and trichomes. Vascular tissue is made up of xylem and phloem tissues and conducts water, m...
https://openstax.org/books/biology/pages/30-chapter-summary
Primary growth occurs at the tips of roots and shoots, causing an increase in length. Woody plants may also exhibit secondary growth, or increase in thickness. In woody plants, especially trees, annual rings may form as growth slows at the end of each season. Some plant species have modified stems that help to store fo...
https://openstax.org/books/biology/pages/30-chapter-summary
Roots help to anchor a plant, absorb water and minerals, and serve as storage sites for food. Taproots and fibrous roots are the two main types of root systems. In a taproot system, a main root grows vertically downward with a few lateral roots. Fibrous root systems arise at the base of the stem, where a cluster of roo...
https://openstax.org/books/biology/pages/30-chapter-summary
Leaves are the main site of photosynthesis. A typical leaf consists of a lamina (the broad part of the leaf, also called the blade) and a petiole (the stalk that attaches the leaf to a stem). The arrangement of leaves on a stem, known as phyllotaxy, enables maximum exposure to sunlight. Each plant species has a charact...
https://openstax.org/books/biology/pages/30-chapter-summary
Water potential (Ψ) is a measure of the difference in potential energy between a water sample and pure water. The water potential in plant solutions is influenced by solute concentration, pressure, gravity, and matric potential. Water potential and transpiration influence how water is transported through the xylem in ...
https://openstax.org/books/biology/pages/30-chapter-summary
Plants respond to light by changes in morphology and activity. Irradiation by red light converts the photoreceptor phytochrome to its far-red light-absorbing form—Pfr. This form controls germination and flowering in response to length of day, as well as triggers photosynthesis in dormant plants or those that just eme...
https://openstax.org/books/biology/pages/30-chapter-summary
abscisic acid (ABA) : plant hormone that induces dormancy in seeds and other organs
https://openstax.org/books/biology/pages/30-key-terms
abscission : physiological process that leads to the fall of a plant organ (such as leaf or petal drop)
https://openstax.org/books/biology/pages/30-key-terms
adventitious root : aboveground root that arises from a plant part other than the radicle of the plant embryo
https://openstax.org/books/biology/pages/30-key-terms
apical bud : bud formed at the tip of the shoot
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apical meristem : meristematic tissue located at the tips of stems and roots; enables a plant to extend in length
https://openstax.org/books/biology/pages/30-key-terms
auxin : plant hormone that influences cell elongation (in phototropism), gravitropism, apical dominance and root growth
https://openstax.org/books/biology/pages/30-key-terms
axillary bud : bud located in the axil: the stem area where the petiole connects to the stem
https://openstax.org/books/biology/pages/30-key-terms
bark : tough, waterproof, outer epidermal layer of cork cells
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bulb : modified underground stem that consists of a large bud surrounded by numerous leaf scales
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Casparian strip : waxy coating that forces water to cross endodermal plasma membranes before entering the vascular cylinder, instead of moving between endodermal cells
https://openstax.org/books/biology/pages/30-key-terms
chromophore : molecule that absorbs light
https://openstax.org/books/biology/pages/30-key-terms
collenchyma cell : elongated plant cell with unevenly thickened walls; provides structural support to the stem and leaves
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companion cell : phloem cell that is connected to sieve-tube cells; has large amounts of ribosomes and mitochondrion
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compound leaf : leaf in which the leaf blade is subdivided to form leaflets, all attached to the midrib
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corm : rounded, fleshy underground stem that contains stored food
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cortex : ground tissue found between the vascular tissue and the epidermis in a stem or root
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cryptochrome : protein that absorbs light in the blue and ultraviolet regions of the light spectrum
https://openstax.org/books/biology/pages/30-key-terms
cuticle : waxy covering on the outside of the leaf and stem that prevents the loss of water
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cuticle : waxy protective layer on the leaf surface
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cytokinin : plant hormone that promotes cell division
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dermal tissue : protective plant tissue covering the outermost part of the plant; controls gas exchange
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endodermis : layer of cells in the root that forms a selective barrier between the ground tissue and the vascular tissue, allowing water and minerals to enter the root while excluding toxins and pathogens
https://openstax.org/books/biology/pages/30-key-terms
epidermis : single layer of cells found in plant dermal tissue; covers and protects underlying tissue
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ethylene : volatile plant hormone that is associated with fruit ripening, flower wilting, and leaf fall
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fibrous root system : type of root system in which the roots arise from the base of the stem in a cluster, forming a dense network of roots; found in monocots
https://openstax.org/books/biology/pages/30-key-terms
gibberellin (GA) : plant hormone that stimulates shoot elongation, seed germination, and the maturation and dropping of fruit and flowers
https://openstax.org/books/biology/pages/30-key-terms
ground tissue : plant tissue involved in photosynthesis; provides support, and stores water and sugars
https://openstax.org/books/biology/pages/30-key-terms
guard cells : paired cells on either side of a stoma that control stomatal opening and thereby regulate the movement of gases and water vapor
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intercalary meristem : meristematic tissue located at nodes and the bases of leaf blades; found only in monocots
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internode : region between nodes on the stem
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jasmonates : small family of compounds derived from the fatty acid linoleic acid
https://openstax.org/books/biology/pages/30-key-terms
lamina : leaf blade
https://openstax.org/books/biology/pages/30-key-terms
lateral meristem : meristematic tissue that enables a plant to increase in thickness or girth
https://openstax.org/books/biology/pages/30-key-terms
lenticel : opening on the surface of mature woody stems that facilitates gas exchange
https://openstax.org/books/biology/pages/30-key-terms
megapascal (MPa) : pressure units that measure water potential
https://openstax.org/books/biology/pages/30-key-terms
meristem : plant region of continuous growth
https://openstax.org/books/biology/pages/30-key-terms
meristematic tissue : tissue containing cells that constantly divide; contributes to plant growth
https://openstax.org/books/biology/pages/30-key-terms
negative gravitropism : growth away from Earth’s gravity
https://openstax.org/books/biology/pages/30-key-terms
node : point along the stem at which leaves, flowers, or aerial roots originate
https://openstax.org/books/biology/pages/30-key-terms
oligosaccharin : hormone important in plant defenses against bacterial and fungal infections
https://openstax.org/books/biology/pages/30-key-terms
palmately compound leaf : leaf type with leaflets that emerge from a point, resembling the palm of a hand
https://openstax.org/books/biology/pages/30-key-terms
parenchyma cell : most common type of plant cell; found in the stem, root, leaf, and in fruit pulp; site of photosynthesis and starch storage
https://openstax.org/books/biology/pages/30-key-terms
pericycle : outer boundary of the stele from which lateral roots can arise
https://openstax.org/books/biology/pages/30-key-terms
periderm : outermost covering of woody stems; consists of the cork cambium, cork cells, and the phelloderm
https://openstax.org/books/biology/pages/30-key-terms
permanent tissue : plant tissue composed of cells that are no longer actively dividing
https://openstax.org/books/biology/pages/30-key-terms
petiole : stalk of the leaf
https://openstax.org/books/biology/pages/30-key-terms
photomorphogenesis : growth and development of plants in response to light
https://openstax.org/books/biology/pages/30-key-terms
photoperiodism : occurrence of plant processes, such as germination and flowering, according to the time of year
https://openstax.org/books/biology/pages/30-key-terms
phototropin : blue-light receptor that promotes phototropism, stomatal opening and closing, and other responses that promote photosynthesis
https://openstax.org/books/biology/pages/30-key-terms
phototropism : directional bending of a plant toward a light source
https://openstax.org/books/biology/pages/30-key-terms
phyllotaxy : arrangement of leaves on a stem
https://openstax.org/books/biology/pages/30-key-terms
phytochrome : plant pigment protein that exists in two reversible forms (Pr and Pfr) and mediates morphologic changes in response to red light
https://openstax.org/books/biology/pages/30-key-terms
pinnately compound leaf : leaf type with a divided leaf blade consisting of leaflets arranged on both sides of the midrib
https://openstax.org/books/biology/pages/30-key-terms
pith : ground tissue found towards the interior of the vascular tissue in a stem or root
https://openstax.org/books/biology/pages/30-key-terms
positive gravitropism : growth toward Earth’s gravitational center
https://openstax.org/books/biology/pages/30-key-terms
primary growth : growth resulting in an increase in length of the stem and the root; caused by cell division in the shoot or root apical meristem
https://openstax.org/books/biology/pages/30-key-terms
rhizome : modified underground stem that grows horizontally to the soil surface and has nodes and internodes
https://openstax.org/books/biology/pages/30-key-terms
root cap : protective cells covering the tip of the growing root
https://openstax.org/books/biology/pages/30-key-terms
root hair : hair-like structure that is an extension of epidermal cells; increases the root surface area and aids in absorption of water and minerals
https://openstax.org/books/biology/pages/30-key-terms
root system : belowground portion of the plant that supports the plant and absorbs water and minerals
https://openstax.org/books/biology/pages/30-key-terms
runner : stolon that runs above the ground and produces new clone plants at nodes
https://openstax.org/books/biology/pages/30-key-terms
sclerenchyma cell : plant cell that has thick secondary walls and provides structural support; usually dead at maturity
https://openstax.org/books/biology/pages/30-key-terms
secondary growth : growth resulting in an increase in thickness or girth; caused by the lateral meristem and cork cambium
https://openstax.org/books/biology/pages/30-key-terms
sessile : leaf without a petiole that is attached directly to the plant stem
https://openstax.org/books/biology/pages/30-key-terms
shoot system : aboveground portion of the plant; consists of non-reproductive plant parts, such as leaves and stems, and reproductive parts, such as flowers and fruits
https://openstax.org/books/biology/pages/30-key-terms
sieve-tube cell : phloem cell arranged end to end to form a sieve tube that transports organic substances such as sugars and amino acids
https://openstax.org/books/biology/pages/30-key-terms
simple leaf : leaf type in which the lamina is completely undivided or merely lobed
https://openstax.org/books/biology/pages/30-key-terms
sink : growing parts of a plant, such as roots and young leaves, which require photosynthate
https://openstax.org/books/biology/pages/30-key-terms
source : organ that produces photosynthate for a plant
https://openstax.org/books/biology/pages/30-key-terms
statolith : (also,amyloplast) plant organelle that contains heavy starch granules
https://openstax.org/books/biology/pages/30-key-terms
stele : inner portion of the root containing the vascular tissue; surrounded by the endodermis
https://openstax.org/books/biology/pages/30-key-terms
stipule : small green structure found on either side of the leaf stalk or petiole
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stolon : modified stem that runs parallel to the ground and can give rise to new plants at the nodes
https://openstax.org/books/biology/pages/30-key-terms
strigolactone : hormone that promotes seed germination in some species and inhibits lateral apical development in the absence of auxins
https://openstax.org/books/biology/pages/30-key-terms
tap root system : type of root system with a main root that grows vertically with few lateral roots; found in dicots
https://openstax.org/books/biology/pages/30-key-terms
tendril : modified stem consisting of slender, twining strands used for support or climbing
https://openstax.org/books/biology/pages/30-key-terms
thigmomorphogenesis : developmental response to touch
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thigmonastic : directional growth of a plant independent of the direction in which contact is applied
https://openstax.org/books/biology/pages/30-key-terms
thigmotropism : directional growth of a plant in response to constant contact
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thorn : modified stem branch appearing as a sharp outgrowth that protects the plant
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tracheid : xylem cell with thick secondary walls that helps transport water
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translocation : mass transport of photosynthates from source to sink in vascular plants
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transpiration : loss of water vapor to the atmosphere through stomata
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trichome : hair-like structure on the epidermal surface
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tuber : modified underground stem adapted for starch storage; has many adventitious buds
https://openstax.org/books/biology/pages/30-key-terms
vascular bundle : strands of stem tissue made up of xylem and phloem
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vascular stele : strands of root tissue made up of xylem and phloem
https://openstax.org/books/biology/pages/30-key-terms