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Questions and Answers
What type of stem tissue pattern contains discrete vascular bundles?
What type of stem tissue pattern contains discrete vascular bundles?
Which type of stems do monocotyledons (monocots) have?
Which type of stems do monocotyledons (monocots) have?
What type of stem lacks a vascular cambium and cork cambium?
What type of stem lacks a vascular cambium and cork cambium?
In which type of stem does xylem lie closer to the center?
In which type of stem does xylem lie closer to the center?
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What is the structure that surrounds a vascular bundle in a monocot stem?
What is the structure that surrounds a vascular bundle in a monocot stem?
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Which type of stem pattern is tubular with a pith in the center?
Which type of stem pattern is tubular with a pith in the center?
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What type of cells are found in the laticifers in the stem with secondary growth?
What type of cells are found in the laticifers in the stem with secondary growth?
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What do tyloses in the xylem do?
What do tyloses in the xylem do?
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What is the function of resin canals found in woody dicotyledonous stems?
What is the function of resin canals found in woody dicotyledonous stems?
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In which part of the tree is heartwood typically found?
In which part of the tree is heartwood typically found?
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How do tangentially cut boards differ from radially cut boards?
How do tangentially cut boards differ from radially cut boards?
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What accounts for about 50% of the wood weight in a living tree?
What accounts for about 50% of the wood weight in a living tree?
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What is the primary function of the vascular cambium in a woody dicotyledonous stem?
What is the primary function of the vascular cambium in a woody dicotyledonous stem?
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What is the primary difference in wood structure between trees that have active vascular and cork cambia all year round versus those with seasonal wood production?
What is the primary difference in wood structure between trees that have active vascular and cork cambia all year round versus those with seasonal wood production?
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What is the primary function of the bark in a woody dicotyledonous stem?
What is the primary function of the bark in a woody dicotyledonous stem?
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In conifers, what is the primary difference in wood structure compared to angiosperms?
In conifers, what is the primary difference in wood structure compared to angiosperms?
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What is the primary difference in wood structure between the spring wood and summer wood in woody dicotyledonous stems?
What is the primary difference in wood structure between the spring wood and summer wood in woody dicotyledonous stems?
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What is the primary use of wood in the United States and Canada?
What is the primary use of wood in the United States and Canada?
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What is the second most widespread use of wood?
What is the second most widespread use of wood?
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What is the main function of the apical meristem at the stem tip?
What is the main function of the apical meristem at the stem tip?
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What are rhizomes?
What are rhizomes?
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What is the main difference between a corm and a bulb?
What is the main difference between a corm and a bulb?
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What are the three primary meristems formed from the apical meristem cells?
What are the three primary meristems formed from the apical meristem cells?
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What are the 'eyes' of a potato?
What are the 'eyes' of a potato?
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What are leaf primordia and bud primordia?
What are leaf primordia and bud primordia?
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What is a leaf gap or bud gap?
What is a leaf gap or bud gap?
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What are cladophylls?
What are cladophylls?
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What is a trace in the context of stem development?
What is a trace in the context of stem development?
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What is the primary difference in wood structure between trees that have active vascular and cork cambia all year round versus those with seasonal wood production?
What is the primary difference in wood structure between trees that have active vascular and cork cambia all year round versus those with seasonal wood production?
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What is the primary function of the vascular cambium in a woody dicotyledonous stem?
What is the primary function of the vascular cambium in a woody dicotyledonous stem?
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What is the primary difference in wood structure between the spring wood and summer wood in woody dicotyledonous stems?
What is the primary difference in wood structure between the spring wood and summer wood in woody dicotyledonous stems?
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What is the primary function of the bark in a woody dicotyledonous stem?
What is the primary function of the bark in a woody dicotyledonous stem?
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What is the main function of the apical meristem at the stem tip?
What is the main function of the apical meristem at the stem tip?
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What structure is found at the angle between the petiole and the stem?
What structure is found at the angle between the petiole and the stem?
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What does the number of groups of bud scale scars indicate?
What does the number of groups of bud scale scars indicate?
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What structure protects the buds on a woody twig?
What structure protects the buds on a woody twig?
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What is the arrangement of leaves called when they are attached in groups of three or more?
What is the arrangement of leaves called when they are attached in groups of three or more?
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What are the paired, often leaflike appendages at the base of a leaf called?
What are the paired, often leaflike appendages at the base of a leaf called?
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What is the term for the region of the stem between nodes?
What is the term for the region of the stem between nodes?
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Which tissue produces secondary xylem and secondary phloem in woody dicotyledonous stems?
Which tissue produces secondary xylem and secondary phloem in woody dicotyledonous stems?
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What is the primary function of cork cells produced by the cork cambium (phellogen) in stems?
What is the primary function of cork cells produced by the cork cambium (phellogen) in stems?
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What do the annual rings in a woody dicotyledonous stem indicate?
What do the annual rings in a woody dicotyledonous stem indicate?
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What is the primary function of vascular rays in woody dicotyledonous stems?
What is the primary function of vascular rays in woody dicotyledonous stems?
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What type of stem tissue pattern is found in herbaceous dicotyledonous stems?
What type of stem tissue pattern is found in herbaceous dicotyledonous stems?
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What is the primary function of lenticels in the stem?
What is the primary function of lenticels in the stem?
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What is the function of the protostele?
What is the function of the protostele?
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What is the primary difference between monocot and dicot stems?
What is the primary difference between monocot and dicot stems?
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What is the function of the sclerenchyma sheath surrounding vascular bundles in monocot stems?
What is the function of the sclerenchyma sheath surrounding vascular bundles in monocot stems?
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What is the primary function of the eustele in woody flowering plants and conifers?
What is the primary function of the eustele in woody flowering plants and conifers?
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What is the primary function of the pith in the siphonostele?
What is the primary function of the pith in the siphonostele?
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What is the primary function of the cotyledons in a seed?
What is the primary function of the cotyledons in a seed?
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What is the primary use of about half of the wood production in the United States and Canada?
What is the primary use of about half of the wood production in the United States and Canada?
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In developing countries, what is approximately half of the cut timber used for?
In developing countries, what is approximately half of the cut timber used for?
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What is the primary function of veneer according to the text?
What is the primary function of veneer according to the text?
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Which specialized stem type is composed almost entirely of stem tissue with papery leaves and is used for storing food?
Which specialized stem type is composed almost entirely of stem tissue with papery leaves and is used for storing food?
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Which specialized stem is characterized by flattened, leaf-like structures and includes prickly pear cactus?
Which specialized stem is characterized by flattened, leaf-like structures and includes prickly pear cactus?
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The apical meristem at the stem tip contributes to increase in stem ______
The apical meristem at the stem tip contributes to increase in stem ______
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Leaf primordia are tiny embryonic ______ that develop into mature leaves
Leaf primordia are tiny embryonic ______ that develop into mature leaves
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The apical meristem cells form three primary ______
The apical meristem cells form three primary ______
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Traces branch off from the cylinder of xylem and phloem, and enter the leaf or ______
Traces branch off from the cylinder of xylem and phloem, and enter the leaf or ______
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A ______ is a strand of xylem and phloem that leaves a gap filled with parenchyma in the cylinder of vascular tissue
A ______ is a strand of xylem and phloem that leaves a gap filled with parenchyma in the cylinder of vascular tissue
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The region of the stem between nodes is called the ______.
The region of the stem between nodes is called the ______.
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The angle between the petiole and the stem is called the ______.
The angle between the petiole and the stem is called the ______.
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The ______ protects the buds on a woody twig.
The ______ protects the buds on a woody twig.
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The arrangement of leaves attached in groups of three or more is called ______.
The arrangement of leaves attached in groups of three or more is called ______.
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The paired, often leaflike appendages at the base of a leaf are called ______.
The paired, often leaflike appendages at the base of a leaf are called ______.
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The number of groups of ______ scars tells the age of the twig.
The number of groups of ______ scars tells the age of the twig.
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Rubber, chicle, and morphine are examples of latex-secreting cells found mostly in the phloem called ______
Rubber, chicle, and morphine are examples of latex-secreting cells found mostly in the phloem called ______
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In woody dicotyledonous stems, the wood of conifers without fibers or vessel elements is known as ______
In woody dicotyledonous stems, the wood of conifers without fibers or vessel elements is known as ______
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Tyloses are protrusions of adjacent parenchyma cells into conducting cells of xylem that prevent the conduction of water and accumulate resins, gums, and tannins, forming ______
Tyloses are protrusions of adjacent parenchyma cells into conducting cells of xylem that prevent the conduction of water and accumulate resins, gums, and tannins, forming ______
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Radially cut boards show annual rings in side view, while tangentially cut boards show annual rings as irregular bands of light and dark streaks in a cut known as ______
Radially cut boards show annual rings in side view, while tangentially cut boards show annual rings as irregular bands of light and dark streaks in a cut known as ______
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In a living tree, about 50% of the wood weight comes from water content, with the dry part composed of about 60-75% cellulose and about 15-25% ______
In a living tree, about 50% of the wood weight comes from water content, with the dry part composed of about 60-75% cellulose and about 15-25% ______
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Tannins and oils in wood repel decay organisms, contributing to its ______ against decay
Tannins and oils in wood repel decay organisms, contributing to its ______ against decay
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The ______ is a solid core, with phloem surrounding xylem, found in primitive seed plants, whisk ferns, club mosses and ferns.
The ______ is a solid core, with phloem surrounding xylem, found in primitive seed plants, whisk ferns, club mosses and ferns.
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In monocot stems, the ______ surrounds the vascular bundles.
In monocot stems, the ______ surrounds the vascular bundles.
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The ______ consists of sieve tubes and companion cells in a monocot vascular bundle.
The ______ consists of sieve tubes and companion cells in a monocot vascular bundle.
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A ______ of sclerenchyma cells surrounds the vascular bundle in a monocot stem.
A ______ of sclerenchyma cells surrounds the vascular bundle in a monocot stem.
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In monocot stems, the ______ is closer to the center of the stem than the phloem.
In monocot stems, the ______ is closer to the center of the stem than the phloem.
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Monocot stems do not have a ______ nor a cork cambium.
Monocot stems do not have a ______ nor a cork cambium.
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Veneer - Thin sheet of desirable wood glued to cheaper ______
Veneer - Thin sheet of desirable wood glued to cheaper ______
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In developing countries, about half of cut timber is used for ______
In developing countries, about half of cut timber is used for ______
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Tubers - Swollen, fleshy, underground ______ Store food
Tubers - Swollen, fleshy, underground ______ Store food
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Bulbs - Large buds surrounded by numerous fleshy leaves, with a small ______ at lower end Store food
Bulbs - Large buds surrounded by numerous fleshy leaves, with a small ______ at lower end Store food
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Corms - Resemble bulbs, but composed almost entirely of ______ tissue, with papery leaves Store food
Corms - Resemble bulbs, but composed almost entirely of ______ tissue, with papery leaves Store food
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Cladophylls Flattened, leaf-like ______ Greenbriars, some orchids, prickly pear cactus
Cladophylls Flattened, leaf-like ______ Greenbriars, some orchids, prickly pear cactus
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Study Notes
Stem Structure
- Stem is comprised of three main components: xylem, phloem, and pith
- Xylem is responsible for water transport, phloem for food transport, and pith for storage
- Xylem consists of tracheids, vessels, and parenchyma cells
- Phloem consists of sieve tubes, companion cells, and parenchyma cells
Tissue Patterns in Stems
- Steles: central cylinder of primary xylem, primary phloem, and pith (if present)
- Protostele: solid core, phloem surrounds xylem (primitive seed plants, whisk ferns, club mosses, and ferns)
- Siphonosteles: tubular with pith in center (ferns)
- Eusteles: discrete vascular bundles (woody flowering plants and conifers)
- Cotyledons: seed leaves attached to embryonic stems, storing food for young seedling
- Dicotyledons (Dicots): flowering plants developing from seeds with two cotyledons
- Monocotyledons (Monocots): flowering plants developing from seeds with a single cotyledon
Monocotyledonous Stems
- No vascular cambium or cork cambium
- Produce no secondary vascular tissues or cork
- Primary xylem and phloem in discrete vascular bundles scattered throughout the stem
- Xylem closer to center of stem, phloem closer to surface
- Parenchyma (ground tissue) surrounds vascular bundles
- In a typical monocot vascular bundle:
- Two large vessels with several small vessels
- First formed xylem cells stretch and collapse, leaving irregularly shaped air space
- Phloem consists of sieve tubes and companion cells
- Vascular bundle surrounded by sheath of sclerenchyma cells
Wood and Its Uses
- Wood: secondary xylem produced by vascular cambium
- Types of sawing:
- Radially cut (quartersawed) boards show annual rings in side view
- Tangentially cut (plainsawed or slab cut) boards show annual rings as irregular bands of light and dark streaks
- Wood composition:
- 50% of wood weight comes from water content
- Dry part of wood composed of about 60-75% cellulose and about 15-25% lignin
- Density: weight per unit volume
- Durability: ability to withstand decay, influenced by tannins and oils
Specialized Stems
- Rhizomes: horizontal stems that grow below-ground and have long to short internodes (irises, some grasses, ferns)
- Runners: horizontal stems that grow above ground and have long internodes
- Stolons: produced beneath the surface of the ground and tend to grow in different directions (potato)
- Tubers: swollen, fleshy, underground stem storing food (potatoes, eyes of potato are nodes)
- Bulbs: large buds surrounded by numerous fleshy leaves, with a small stem at lower end storing food (onions, lilies, hyacinths, tulips)
- Corms: resemble bulbs, but composed almost entirely of stem tissue, with papery leaves storing food (crocus and gladiolus)
- Cladophylls: flattened, leaf-like stems (greenbriars, some orchids, prickly pear cactus)
Origin and Development of Stems
- Apical meristem at stem tip contributes to increase in stem length
- Dormant before growing season begins, protected by bud scales and leaf primordia
- Leaf primordia and bud primordia develop into mature leaves and buds
- Traces branch off from cylinder of xylem and phloem, and enter leaf or bud
- Each trace leaves a gap filled with parenchyma in the cylinder of vascular tissue, forming leaf gap or bud gap
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Description
Test your knowledge on the origin and development of stems in plants, including the role of apical meristem, primary meristems, and protective structures like bud scales and leaf primordia.