AGV03/BIOLV23 Chapter 7: Plant Organs - Stems
Stem Function
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Connects ____________ to ____________
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Usually ____________
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____________ & ____________ leaves/flowers/fruit
____________
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____________ & ____________ up from soil
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________________________ throughout plant
Produce _____________________
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____________ growth, some with ____________ growth
Anatomy of Woody Twigs
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All stems contain ____________
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Undeveloped ____________ that contains an embryonic ____________
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May be ____________ (at tip of stem)
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May be ____________ (on the side of stem)
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The area where on the stem where each leaf is attached is called a ____________
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The area on the stem between two nodes is called ____________
1 Algiers, K Fall 2010 AGV03/BIOLV23 Algiers, K Fall 2010 Stems of Herbaceous Eudicots
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With vascular bundles __________________________around the ____________
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____________ – outer covering; protects
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____________ – waxy layer that reduces water loss
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____________ – Cylinder (several cells thick)
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Parenchyma, collenchyma, & sclerenchyma cells
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Various functions: ____________, ____________ , photosynthesis
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____________ is the central ________________, (xylem to pith)
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Vascular bundles include ____________ and ____________
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________________________ contain lateral meristem cells for 2° growth
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____________ - ground tissue composed of thin-walled parenchyma cells (funct: storage)
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_____________________ – cells between pith & cortex
2 AGV03/BIOLV23 •
Herbaceous Eudicots: Stem vs. Root (Table 7-1)
Stems of Monocots
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With vascular bundles _____________________ throughout the stem
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Xylem point ______________& Phloem point ______________
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_______________________– sclerenchyma cells for support
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Monocots don’t have ________________________ (no 2° growth)
Stems of Woody Dicots
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_____________________ growth in lateral meristem
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Vascular cambium -makes __________ & ________________
(2° xylem & phloem)
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Cork cambium – makes __________ cells & __________ parynchyma
= outer bark (__________________)
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3 Algiers, K Fall 2010 AGV03/BIOLV23 •
Plant changes from _____________ looking stem to __________ looking stem, gradually
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vascular cambium is the blue cylinder
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Vascular cambium divides, forming
2° xylem (________________) & 2° phloem (________________)
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____________________ (outer bark) replaces 1° phloem, cortex, & epidermis
4 Algiers, K Fall 2010 AGV03/BIOLV23 •
Stems of Woody Dicots
Common Terms associated with wood
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__________________- functional 2°xylem
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__________________- – older, dead wood
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__________________- - flowering plant wood (woody eudicots)
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Furniture, more expensive, grows slower
__________________- – conifer wood (lacks fibers & vessel elements)
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Building material (cabinets, houses) grows fast; less expensive
5 Algiers, K Fall 2010 AGV03/BIOLV23 Algiers, K Fall 2010 Tree Rings
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In __________________- climates, woody plants grow quickly in spring & summer, &
are dormant in the winter
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__________________- has large diameter tracheids & vessel elements
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Late __________________- has thicker-walled, narrow conducting cells & fibers
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_____________________________- display _________ year’s growth
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Tree Ring Analysis can give information about __________________,
__________________, __________________, & ______________________
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As far as 9,000 yrs (bristlecone pines in US)
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Tree rings are studied by _________________________
The Importance of Forests
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Forests cover ________ of the Earth’s land
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They play an important role in _________________
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_________________is a great threat to our environment & our air (_______ & _______)
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Read pg 145
Specialized Stems
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Stems may be modified
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Can _________________________ reproduce (split) to give rise to new individuals
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_________________ - horizontal underground stems growing below ground
(may be fleshy or not)
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_________________ - thickened ends of rhizomes, fleshy, and store food
6 AGV03/BIOLV23 •
Algiers, K Fall 2010 _________________ – rounded, fleshy underground bud with
short stems & fleshy leaves
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_________________ – short, thick underground stem that superficially resembles a
bulb; doesn’t store food
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_________________ – (runners) horizontal aerial stems that grow along
the ground surface; contain long internodes
Review Questions
1. Draw a Woody Twig and label: node, internode, axillary bud; terminal bud.
Define each structure next to the picture
2. Draw a stem of a herbaceous eudicot and label the following: epidermis, cuticle, cortex,
stele, vascular cambium, pith, pith rays
7 AGV03/BIOLV23 Algiers, K Fall 2010 3. Draw a stem of a monocot and label the following: epidermis, xylem, phloem, bundle
sheath, vascular bundle, ground tissue
4. What does the vascular cambium in a woody eudicot do? What about the cork cambium?
Distinguish the inner bark, outer bark, and wood
5. Draw a stem of an older woody eudicot and label the following: pith, 1° xylem, one
annual ring, 2° xylem & phloem, vasciular cambium, periderm, xylem rays
8 AGV03/BIOLV23 Algiers, K Fall 2010 6. What is the difference between sapwood and heartwood?
7. What is the difference between hardwood and softwood?
8. What causes the formation of tree rings and what can people who study tree rings (name
them) conclude after looking at them?
9. Are forests important? Why? Name a threat to our rainforests
10. Name five specialized stems and describe how to identify them
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