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Plant Reading Guide
The Importance of Plants
Cereals are grasses that contain grains. Grains are the edible, dry fruits of a cereal, such as rice,
wheat, corn, oats, sorghum, rye, and millet. Root crops are roots of underground stems that are rich in
carbohydrates. Root crops include potatoes, beets, carrots, and radishes. Legumes are members of the pea
family and bear protein-rich seeds in pods. Soybeans are the most important legume crop because they are
produced in the largest amount and have many important uses. A fruit is the part of the flowering plant that
usually contains seeds. Food derived from the leaves, stems, seeds, and roots of soft plants are often called
vegetables. Most nuts have a hard outer layer and contain a dry, one-seed fruit. Nuts include almonds,
walnuts, pecans, and hazelnuts.
The study of the interactions between plants and the environment is called plant ecology. The most
important interaction involves the ability of plants to capture solar energy through photosynthesis. In
photosynthesis, plants absorb carbon dioxide from the air, produce sugar and break apart water, releasing
oxygen into the air. Consumers use oxygen in aerobic respiration and produce carbon dioxide and water.
Organic compounds from plants provide consumers with energy, building blocks, and essential molecules like
vitamins and fibers.
Plant Evolution and Classification
Plants can be divided into two groups based on the presence of vascular tissue. Nonvascular plants have neither true
vascular tissue, nor true roots, stems, or leaves. Most members of the vascular plant group have vascular tissue and true roots,
stems, and leaves. Vascular plants can further be divided into two groups—seedless plants and seed plants. Seedless plants
include the phylum of ferns and three phyla made up of plants closely associated with ferns. Seed plants—plants that produce
seeds for reproduction—include four phyla of gymnosperms and one phylum of angiosperms. Gymnosperms, which include pine
trees, produce seeds that are not enclosed in fruits. Angiosperms, also known as flowering plants, produce seeds in a protective
fruit. Examples are apple and orange trees.
Bryophytes are mostly terrestrial, or found on land. They are seedless, produce spores, and are usually very small
because they don’t have vascular tissue—usually less than 2 cm in height. Mosses, one kind of bryophyte, are called pioneer
plants because they are often the first species to inhabit a barren area. This is an important environmental function because
mosses gradually accumulate inorganic and organic matter on the surface of rocks, creating a layer of soil in which other plants
can grow. In areas devastated by fire, volcanic action, or human activity, pioneering mosses can help trigger the development of
new biological communities. They also help prevent soil erosion by covering the soil surface and absorbing water.
Comparing Monocots and Dicots
Use your notes that we discussed today in class!
Plant Structure and Function
Leaves come in a wide variety of shapes and sizes and are an important
feature used for plant identification. The broad, flat portion of a leaf, called
the blade, is the site of most photosynthesis. The blade is usually attached to
the stem by a stalk-like petiole. The maple leaf is a simple leaf; it has a
single blade. In compound leaves such as a white clover, the blade is divided
into leaflets.
Leaves consist of three tissue systems. The dermal tissue system is
represented by the epidermis. In most leaves the epidermis is a single layer of
cells coated with a nearly impermeable cuticle. Water, oxygen, and carbon
dioxide enter and exit the leaf through stomata in the epidermis. Epidermal
hairs are often present and usually function to protect the leaf from insects and
intense light.
Sexual Reproduction in Flowering Plants
Flower parts are usually found in four concentric whorls, or rings.
Sepals make up the outermost whorl of flower parts. They surround and
protect the other parts of a developing flower before it opens. Petals
make up the next whorl. The petals and sepals of wind-pollinated plants
are usually small or absent. The two innermost whorls of flower parts
contain the reproductive structures. The male reproductive structures are
stamens, each of which consist of an anther and a filament. An anther
produces the pollen. A stalk-like filament supports the anther. The
innermost whorl contains the female reproductive structures, which are
called the capel. One or more carpels fused together are called a pistil.
A style, which is also stalk-like, rises from the ovary. The tip of the
style is called the stigma. Generally, a stigma is sticky or has hairs,
enabling it to trap pollen grains. Most species of flowering plants have
flowers with both stamens and carpels. However, some species have flowers
with only stamens or carpels.
Seasonal Responses
Some trees leaves are noted for their spectacular fall color. The changing
fall colors are caused mainly by a photoperiodic response but also by a
temperature response. As night becomes longer in the fall, leaves stop producing
chlorophyll. As the chlorophyll degrades, it is not replaced. Other leaf
pigments, the carotenoids become visible as the green chlorophyll degrades.
Carotenoids include the orange carotenes and the yellow xanthophylls. The
carotenoids were always in the leaf; they were just hidden by the more abundant
chlorophyll. Another group of pigments found in leaves, the anthocyanins, are
produced in cool, sunny weather. Anthocyanins produce beautiful red and
purplish-red flowers.
Plants as Medicines
For thousands of years, people throughout the world have used plants to treat illness. Ethnobotanists—scientists who
study the plant knowledge of native cultures—have made many discoveries that led to the development of important medicines
we use today. In fact, one fourth of all prescription drugs in the US have plant chemicals as an active ingredient.
In the early 1600s, a European monk saw Native Americans in the Andes Mountains grind the roots, bark and branches
of the cinchonas trees. They used the finely ground powder they called “fever bark” to treat high body temperatures. The feverreducing ingredient in the plant is called quinine, from the Spanish word quinaquina. Today, an artificial form of quinine is used
in controlling the recurrence of a disease called malaria.
The commonly used drug, aspirin, came from a plant called queen of the meadow. Many years ago, the roots of the
plant were boiled. People drank the “tea” containing salicylic acid as a treatment for fever and pain. Today, we use a synthetic
form of aspirin with the same characteristics.
Some cancer medicines were discovered because Native Americans used the rosy periwinkle plant in the treatment of
diabetes. When scientists studied the plant to find out whether it was effective against diabetes, they discovered that two of the
plant’s ingredients kill leukemia cells. Their findings resulted in treatments for leukemia and Hodgkin’s disease.
In the mid-1990s, ethnobotanists began looking at a plant used by native healers to treat diseases caused by viruses. The
native healers, or shamans, traditionally have been the one trained to know which plants are good for healing. Ethnobotanists
found that the plant used by the shamans contains a chemical called prostratin. Prostratin might stop the growth of the virus
that causes AIDS. Some ethnobotanists think shamans could be an important link in the process of turning plants into
prescriptions.
Plant Reading Guide Questions
The Importance of Plants
1.
2.
3.
4.
5.
6.
Underground stems that are rich in carbohydrates are called _______________________.
Foods derived from leaves, stems, and seeds, or roots of soft plants are called ____________________.
Grasses that contain grains are called _____________________.
________________ bear protein-rich seeds in pods.
The edible, dry fruits of a cereal are called ______________________.
During photosynthesis, plants absorb _____________ _______________, produce ____________, and release
_________________.
7. Plants capture energy from the sun to provide consumers with ___________ and essential molecules.
8. Consumers use the oxygen to carry out _______________ ________________.
Plant Evolution and Classification
Complete the following analogies:
9. Seed plants are to angiosperms as seedless plants are to ____________________.
10. Orange tree is to angiosperm as pine treed is ___________________.
11. Mosses belong to the nonvascular group of plants called _________________.
12. Why are mosses known as “pioneers”?
Comparing Monocots and Dicots
Use the chart to answer the following questions.
13. One cotyledon is to monocot as two cotyledons is to _________________
14. Radially arranged vascular bundles is to ______________ as scattered vascular bundles is to monocots.
15. Which flowers would have flower parts occurring in 3s? (circle them)
carnation,
iris,
rose,
tulip
16. Which plants would have leaves with net venation? (Circle them)
Corn, maples,
rice,
barley,
beans
Plant Structure and Function
17.
18.
The site for most photosynthesis is the _______________ of the leaf.
The petiole attaches the leaf to the ____________.
19.
Simple leaf is to maple as compound leaf is to _______________.
20.
The _____________ located in the epidermis allow for water, carbon
dioxide, and oxygen to exit.
21. The leaf is protected from insects and intense light by ______________
_____________.
Sexual Reproduction in Flowering Plants
22.
The structures that surround and protect parts of a developing flower
are called _______________.
23.
The structure that traps pollen grains with its sticky surface is
called the _________________.
24.
The female reproductive structures can be called the ________________.
25.
The male reproductive structures are called the __________________.
26.
A pistil is one or more _____________ fused together.
Seasonal Responses
27.
What are the 2 main causes of fall colors in leaves?
__________________ __________________
28.
Why do most leaves appear to be green?
29.
The yellow and orange colors on leaves are produced by the pigments
_________________.
30.
The red and purplish-red flowers are produced by the pigments
____________________.
Plants as Medicines
31. The author thinks ethnobotany is
A. Not effective
C. Only good for curing fevers
B. Not worthwhile
D. A valuable science
32.
A.
B.
C.
D.
What is the author’s main point in this passage?
Aspirin was developed many years ago from salicylic acid tea
All plants contain powerful medicines
Important medicines have come from plants.
Ethnobotanists study the plant knowledge of native cultures
33.
A.
B.
C.
D.
What does the word shaman in the last paragraph mean?
A person who looks at plants used by native healers
A person trained to know which plants are good for healing
The bark and branches from the cinchonas tree
The study of native healing
34. What did Native Americans use powder from the cinchonas tree for?
A. To fight diabetes
B. To cure malaria
C. To treat fevers
D. To treat pain
35. Describe how the medicines that are used to treat leukemia and Hodgkin’s disease were discovered.