Download Warmup Exercise: Modified True or False 1. An angiosperm

May 17, 2013
Warm­up Exercise:
Modified True or False
1. An angiosperm produces cones bearing seeds
2. Rice, apple tree, bamboo, palm trees and grass are examples of angiosperms.
3. A monocot has a single cotyledon (seed­leaf), parallel veins, and vascular bundles arranged in a ring.
4. Areas of plants that are growing have vast amounts of dermal tissue.
Homework was the Monocot/Dicot chart and p 530 #1­3, 5
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Homework: pg 530 # 1, 2, 3, 5
pg 534 # 1, 3­6
pg 530
1. Key difference: whether or not the seed has a covering ­ gymnosperm = "naked seed" (no covering) while angiosperm develop seed in a flesh ovary (fruit)
2. The onion is a monocot because of the single leaf cotyledon (seed leaf). 3. Monocot
parallel veins
narrow leaves
less prominent flowers
Dicot
netted veins
broad leaves
more prominent flowers
floral parts in floral parts in multiples of 4 or multiples of 3
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one seed leaf
two seed leaves
lack secondary secondary growth
growth 4. 5. Split open and count number of seed leaves. 2
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Roots
• Originally characterized as the part of the plant that grew underground
• But
> aerial roots
– grow above ground
> aerating roots
– grow upward (especially above water)
• Now characterized as the part of the plant body that bears no leaves (or nodes)
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Root functions
1. Anchor the plant
2. Absorb water and inorganic nutrients
3. Can act as storage organs
4. Can enter into symbiotic relationships with fungi and/or bacteria in the soil in order to obtain nutrients easier
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Root Morphology
• The tip of each root has a conical covering of tissue known as the root cap
• Underneath the root cap is the apical meristem
> the root region undergoing mitosis
> grows and pushes the root through the soil
• Outer surface of the root is known as the epidermis
• The epidermis produces outgrowths known as root hairs that increase the surface area for absorption
• Under the epidermis lies the cortex whose primary role is starch storage
• the innermost layer of the cortext is the endodermis
> acts as a barrier to the nutrients, preventing them from passively entering the vascular tissue
> this allows the plant to accumulate lots of minerals in its roots
• Inside the endodermis lies the vascular tissue
> where water and nutrients start their journey up the plant
> an area of sugar movement or storage depending on environmental conditions
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Root Cross­section
epidermis
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The Structure of a Root
zone of maturation
zone of elongation
meristematic region
root cap
­ mostly dead cells
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Root Growth
• Roots grow in the direction of the correct oxygen, moisture and nutrient levels for the plant growth
• Primary growth is elongation • Secondary growth is an increase in the diameter
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Root Systems
• There are two main types of root systems:
1) Taproot system where there is a large primary root with lots of smaller, secondary roots emerging from it. It is found mostly in dicots where starch storage is key.
2) Fibrous System (or “adventitious”) where there is no primary root and all roots are similar in size. They jut out in all directions. Found commonly in monocots. The main function is anchorage.
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Stems
• Another structural axis for the plant after roots
• Composed of nodes and internodes
• Nodes hold buds which can grow into leaves, flowers, cones, branches
• Internodes are the spaces between nodes
• Stems are usually located above the surface, but there are some plants with underground stems
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Stem Functions
1. Support and elevation for leaves, flowers and fruits
2. Transport of materials between the roots and the shoots (areas of new plant growth)
3. Nutrient storage
4. Annual, lateral, plant growth
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Types of Stems
• Herbaceous: softer texture stems that die at the end of the growing season
• Woody: hard textured stems with secondary xylem
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Dicot Stems
• Pith in the center
• Outside of the stem is still the epidermis
• Lateral growth is due to the vascular bundles in a ring
• Each vascular bundle has a meristem , called vascular cambium between the xylem and phloem
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Cross­section of a Dicot Stem (Figure 14.31, page 542, plus some)
vascular cambium
phloem
xylem
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If woody stem
• Secondary xylem grows to the inside while secondary phloem grows to the outside
• The epidermis and cortex get destroyed as the secondary xylem and phloem grow
• The plant produces a cork cambium layer on the outside which replaces the epidermis
• The outer region develops into the bark which protects the outside of the woody dicot
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Dendrochronology
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Monocot Stems
• Have vascular bundles throughout, through usually concentrated near the edge
• Rarely produce secondary growth
• Grow laterally due to anomalous growth
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Cross­section of a Monocot Stem 20
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Specialized stems
• Bulb: short underground stem with fleshy leaves attached
• Climbing: stems that cling to or wrap around other plants or structures
• Rhizome: a horizontal, underground stem used mainly in reproduction but also in storage
• Stolons/runners: horizontal, above ground stems to produce new rooted plantlets when they touch the surface
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pg 534 #1, 3­6
1. Both are transport elements. Xylem transports water and minerals up from roots to leaves, phloem transports sugar and manufactured products from leaves to storage (roots). 2. 3. Water
4. Without xylem, no water would be available for photosynthesis = plant would die. Without phloem, sugars wouldn't be able to move to parts of the plant that need it = plants would starve. 5. Day because there would be ample amount of sunlight for photosynthesis. 6. Prevents water from moving up and sugars from moving down. 22
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