Download Answers to Review Questions Chapter 24 Review Questions Page

Answers to Review Questions
Chapter 24
Review Questions Page 105
1 Sketch the following tissues in the boxes
below: parenchyma cells, collenchyma cells,
sclereids, epidermal cells, stomata and guard
cells, periderm, vascular bundle with xylem,
and vascular bundle with phloem.
The drawings will vary. See lab book diagrams for confirmation.
2 Compare and contrast xylem and phloem.
In plants the xylem carries water and the phloem carries organic nutrients (food).
3 Why was the evolution of vascular tissue important to plants conquering the land?
The evolution of vascular tissue allowed land plants to have an efficient system of distributing water and
nutrients.
Also, the plants gained support.
4 Describe the arrangement of vascular bundles in eudicots and monocots.
In eudicots, the vascular bundles form a ring around the outside of the stem. In both the eudicots and the
monocots,
the phloem faces outward and the xylem faces inward.
In most monocots (except some grasses with a ground tissue cavity, such as wheat), the vascular
bundles are
spread throughout the ground tissue.
5 Compare and contrast the roots, stems, and leaves of eudicots and monocots.
Roots: In the fibrous root system found in monocots, the primary root is poorly developed, and the
secondary roots
are well developed. The primary root is well developed in eudicots.
Stems: In monocots the stem vascular bundles are scattered, and in eudicots the stem vascular bundles
form a ring
shape around the stem.
Leaves: In monocots, there are usually a number of major leaf veins that run parallel to the length of the
leaf; in
eudicots, the leaves have netted venation.
6 What are several functions of roots?
Roots are plant organs that evolved to anchor and support a plant, absorb water and necessary minerals,
store
food, and produce growth-stimulating hormones. The majority of the root system is found underground,
although
some plants, such as the tropical fig, possess extensive aerial roots.
7 Label the following root micrographs.
1. Remnants of epidermis
2. Cortex
3. Endodermis
4. Phloem
5. Xylem
1. Epidermis
2. Cortex
3. Endodermis
4. Xylem
5. Phloem
8 Name and describe three types of specialized roots.
Prop roots help to anchor and brace the plant against wind. Dodder (Cuscuta sp.) possesses parasitic
roots called
haustoria that parasitize a host plant. Some members of the pumpkin family (Curcurbitaceae spp.) that
live in dry
climates produce large water storage roots. Certain species of figs and swamp trees, such as the tupelo
and bald
cypress, have expanded buttress roots for stability in wet environments.
9 Sketch a woody twig, and label the following
structures: terminal bud, lenticels, node, internode,
terminal bud scale scars, axillary bud, leaf scar.
10 Name and describe three types of specialized stems.
Rhizomes are a type of modified stem in which the stem grows horizontally below the ground, resembling
a root.
The rhizome may be slender, as in some grasses and ferns, or a thick structure, as in some irises. Some
plants
possess runners and stolons.
Runners are similar to rhizomes except that they are above ground. Strawberry plants produce runners
after they
flower. In philodendrons, runners can be seen giving rise to new plants spilling from a basket.
Tubers are swollen extensions of stolons, modified to store carbohydrates. The Irish potato is an example
of a tuber.
The eyes of the potato are actually axillary buds.
11 Label the following stem micrographs.
1. Bark
2. Annual ring
3. Ray
4. Springwood
5. Pith
6. Summerwood
7. Wood
1. Vascular bundles
2. Pith
3. Cortex
4. Epidermis
5. Xylem
6. Phloem
12 Sketch a leaf, and describe its phyllotaxy.
The arrangement of leaves on a stem is
the phyllotaxy. In plants with opposite leaf
attachment, such as dogwood and maple,
two leaves are attached at each node. In
alternate leaf arrangement, such as in
poplar and aspen, a single
leaf appears at each node. Most plants have the
alternate leaf arrangement. In whorled
leaf arrangement, as in bedstraw and
oleander, three or more leaves are
attached at a single node.
13 Describe and sketch several types of leaf venation.
Sketches will vary. The veins of a leaf are
composed of vascular tissue. In basal
dicots and eudicots, the veins are
arranged in a netted or reticulate pattern.
Pinnately veined leaves, such as in
apple and cabbage, have one prominent
primary vein, or midrib, and secondary
veins branch off the midrib. In palmately
veined leaves, such as in sycamore and
sweetgum, several primary veins branch
out from a single point. Monocots, such
as corn and sugarcane, have parallel
venation, in which the veins are
arranged nearly parallel to each other.
Interestingly, Ginkgo biloba has no
midrib and the veins fork out from the
base of the blade. Ginkgo leaves exhibit
dichotomous venation.
14 Name and describe three types of specialized leaves.
Thick, water-retaining succulent leaves, such as aloe, jade tree, and yuccas, can be found in plants from
arid regions
to salty seashores. The spines of cacti, effective defenses, are actually modified leaves that evolved to
conserve
water. Bracts are specialized leaves at the base of a flower. The brightly colored bracts of poinsettia are
popular at
Christmas. The obvious white or pink bracts of dogwood resemble flower petals.
15 Describe the orientation of xylem and phloem in roots, stems, and leaves.
Roots—in eudicots, the xylem is star shaped with several radiating arms. The phloem is located between
the radiating
arms. In monocots, ground tissue forms the pith, centrally located. Vascular tissue is located in bundles in
a ring
surrounding the pith, with the xylem oriented exteriorly and the phloem oriented interiorly.
Stems—in both the eudicots and the monocots, the phloem faces outward and the xylem faces inward.
Leaves—the veins of a leaf are composed of xylem on the top side of a vein and phloem on the bottom
side of a
vein.
16 Label these micrographs of leaves.
1. Palisade mesophyll
2. Spongy mesophyll
3. Leaf vein (midrib)
4. Trichome
1. Bundle caps (fibers)
2. Ground tissue
3. Epidermis
4. Vascular bundle
5. Xylem