Podcast
Questions and Answers
What is the main characteristic of stems that enables them to grow towards light?
What is the main characteristic of stems that enables them to grow towards light?
- Thermotropism
- Hydrotropism
- Phototropism (correct)
- Geotropism
Which part of the plant develops into the stem?
Which part of the plant develops into the stem?
- Radicle
- Cotyledon
- Root
- Plumule (correct)
What type of stem is characterized by a thin and elongated structure that cannot stand erect?
What type of stem is characterized by a thin and elongated structure that cannot stand erect?
- Woody stems
- Prostrate stems
- Herbaceous stems
- Creepers (correct)
Which type of stem modifies itself for storage of food?
Which type of stem modifies itself for storage of food?
In a twig, what do you call the region of the stem where leaves are attached?
In a twig, what do you call the region of the stem where leaves are attached?
Which of the following stem modifications supports climbing?
Which of the following stem modifications supports climbing?
What is the term for stems that are capable of conducting water and minerals?
What is the term for stems that are capable of conducting water and minerals?
Which arrangement of leaves is described when they are attached in pairs on the stem?
Which arrangement of leaves is described when they are attached in pairs on the stem?
What is the primary function of prickles in plants?
What is the primary function of prickles in plants?
Which plant is an example of having terminal buds that develop into tendrils?
Which plant is an example of having terminal buds that develop into tendrils?
Which of the following stems is primarily used as a source of sucrose?
Which of the following stems is primarily used as a source of sucrose?
What are bulbils primarily used for in plants?
What are bulbils primarily used for in plants?
Which of these plants is commonly used for industrial fibers sourced from its stem?
Which of these plants is commonly used for industrial fibers sourced from its stem?
Which of the following is not a culinary use of underground stems?
Which of the following is not a culinary use of underground stems?
Which plant produces latex that is used in rubber production?
Which plant produces latex that is used in rubber production?
What is the main purpose of stems producing gums in certain plants?
What is the main purpose of stems producing gums in certain plants?
What is the term used to describe the xylem produced in spring that has relatively large vessel elements?
What is the term used to describe the xylem produced in spring that has relatively large vessel elements?
How does the size of vessel elements change during the growing season in a broadleaf tree?
How does the size of vessel elements change during the growing season in a broadleaf tree?
What does an annual ring in a tree represent?
What does an annual ring in a tree represent?
Which of the following factors can contribute to a narrower annual ring?
Which of the following factors can contribute to a narrower annual ring?
What type of wood predominates in conifers compared to broadleaf trees?
What type of wood predominates in conifers compared to broadleaf trees?
What tool can be used to determine the age of a woody plant without cutting it down?
What tool can be used to determine the age of a woody plant without cutting it down?
What indicates that a year had higher than normal growth conditions in a tree's life?
What indicates that a year had higher than normal growth conditions in a tree's life?
What evidence might you find next to an annual ring to indicate a past fire event?
What evidence might you find next to an annual ring to indicate a past fire event?
What is the primary characteristic of siphonosteles found in ferns?
What is the primary characteristic of siphonosteles found in ferns?
In which type of plants are eusteles predominantly found?
In which type of plants are eusteles predominantly found?
What type of vascular bundles do herbaceous dicotyledonous stems primarily have?
What type of vascular bundles do herbaceous dicotyledonous stems primarily have?
Which statement accurately describes the cambium in herbaceous dicot stems?
Which statement accurately describes the cambium in herbaceous dicot stems?
How do woody dicotyledonous stems differ from herbaceous dicots as they mature?
How do woody dicotyledonous stems differ from herbaceous dicots as they mature?
What feature distinguishes the wood in tropical trees from that in temperate trees?
What feature distinguishes the wood in tropical trees from that in temperate trees?
What happens to the growth patterns of woody plants in temperate climates?
What happens to the growth patterns of woody plants in temperate climates?
What role does the procambium play in vascular development?
What role does the procambium play in vascular development?
What is the primary function of resin produced by resin canals?
What is the primary function of resin produced by resin canals?
How long do the fascicles of bristlecone pines typically persist?
How long do the fascicles of bristlecone pines typically persist?
Which tissue is referred to as bark?
Which tissue is referred to as bark?
What happens to older layers of phloem over time?
What happens to older layers of phloem over time?
What do the sieve tubes in younger layers of phloem primarily transport?
What do the sieve tubes in younger layers of phloem primarily transport?
What are laticifers in plants known for?
What are laticifers in plants known for?
Which statement is true about the parenchyma cells of the cortex?
Which statement is true about the parenchyma cells of the cortex?
Which plant cells commonly contain multiple nuclei?
Which plant cells commonly contain multiple nuclei?
Study Notes
General Structure of Stems
- Stems develop from the plumule and are the aerial part of the plant.
- Composed of axis, nodes, internodes, and buds.
- Types include aerial, sub-aerial, and underground stems.
- Mechanical tissue presence classifies stems as weak (creepers, climbers, twinners), herbaceous, or woody.
- Functions include supporting leaves for photosynthesis, conducting water and nutrients, and producing flowers and fruits.
External Structure of Stems
- Woody twigs consist of an axis with attached leaves.
- Leaf arrangements can be alternate, opposite, or whorled.
- Nodes are where leaves attach; internodes are the segments between nodes.
- Stem types include siphonosteles (common in ferns) and eusteles (discrete vascular bundles as seen in flowering plants).
Herbaceous Dicotyledonous Stems
- Characterized by green, nonwoody stems, typically in annual plants.
- Vascular bundles contain patches of xylem and phloem formed in a cylindrical arrangement.
- Procambium initially produces only primary xylem and phloem; later, vascular cambium develops for secondary growth.
Woody Dicotyledonous Stems
- Young stems show similar arrangements in primary tissues before differences emerge with the vascular cambium and cork cambium.
- Secondary xylem (wood) develops seasonally, creating annual growth rings.
- Spring wood features large vessel elements; summer wood has smaller elements and more tracheids.
- Annual rings indicate tree age and reflect environmental conditions experienced during growth.
Stem Modifications
- Prickles and thorns develop from outer stem tissues for protection.
- Stem tendrils, such as those in vines, provide structural support.
- Bulbils modify floral buds for vegetative propagation, as seen in Dioscorea and Agave.
Uses of Stems
- Underground stems can serve as food (e.g., potato, garlic) or spices (e.g., ginger).
- Stems like jowar and rice are valuable as fodder.
- Industrial fibers are sourced from jute, hemp, and flax.
- Sugarcane stems are harvested for sucrose; latex from certain stems, like rubber trees, is used commercially.
- Wood from various plants serves medicinal purposes (e.g., quassia, sandalwood).
- Gums from injured stems are utilized in various industries (e.g., gum-acacia).
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Description
Explore the detailed morphology of stems in this quiz based on PBS 101.23. Topics include the general, external, and internal structures of stems, as well as stem modifications and their uses. Enhance your understanding of plant anatomy with these key concepts.
