BIOLOGY 343 – PLANTS AND PEOPLE
SUMMER 2010
Date
Labs and Field Trips
July 5
Field Trip: Pacific Spirit Park
July 7
Lab #1: Plant Structure I
July 8
Lab #1: Plant Structure I (Quiz #1)
July 9
Library Orientation: Meet in lecture (Quiz #2)
Lab #2: Plant Structure II (afternoon)
July 12
Field Trip: Arboretum Tour (am)
July 14
Lab #3: Plant Reproduction (Quiz #3)
July 15
Lab #4 – Plant Families I
July 16
Guest Lecture (not optional): Plants to Dye For
Optional Lab Activity: Plants to Dye For (afternoon)
July 19
Lab #5 – Plant Families II (Quiz #4)
July 21
Optional Fieldtrip: UBC Farm (morning)
Lab #6 – Plant Families III (afternoon)
July 22
Optional Fieldtrip: Chinatown
July 23
Optional Fieldtrip: Anthropology Museum
July 26
Lab #7 – Medicinal and Poisonous Plants,
Spices, etc (Quiz #5)
July 27 (Tues)
Optional Fieldtrip: UBC Botanical Garden
July 28
Lab Final Exam (am)
July 28 - 30
Class Presentations
TBA
Optional Fieldtrip: Brewery Tour
Front Cover by Kate Saunders
Page 40
BIOLOGY 343
INTRODUCTION TO LABS #4, #5, #6
Objectives:
By the end of the next three labs you will be able to:
1. Explain how plants are classified and the application of rules of nomenclature.
2. Name the most common plant families utilized by humans.
3. Demonstrate observational and recording skills.
4. Apply terminology of structure and floral morphology to different plants.
Compare and contrast
Explain results of experimental activities.
5. Identify examples of the various ways in which man uses plants.
6. Predict the family to which a plant belongs based on its morphological and/or
floral features.
PLANT CLASSIFICATION (Levetin and McMahon, pages 123 – 138)
Although scientific names can be pretty incomprehensible to the layperson they
are important because there is a lot of information associated with a name. Taxonomy
is the science of describing, naming, and classifying organisms. Most plant
classification systems are based on reproductive structures (flowers). Plants are
named by using rules of binomial nomenclature, which means that each species has a
name of two parts (eg. Rosa nootkatensis). The first is the genus (eg. Rosa). The
second (specific epithet), which must always be prefaced with the genus, gives the
name of the species. The first letter of the genus is capitalized, whereas the first letter
of the specific epithet is usually not. Both must be either italicized or underlined.
Classification is hierarchical. The species is the narrowest category and the
kingdom is the broadest. Here are the taxonomic levels using corn as an example:
Kingdom:
Phylum:
Class:
Order:
Family:
Genus:
Species:
Plantae
Anthophyta
Monocotyledones
Commelinales
Poaceae
Zea
Zea mays
The classification of organisms into groups determined by their evolutionary
relationships is called systematics. A systematist seeks to reconstruct the evolutionary
history (phylogeny) of organisms.
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In the next three labs we will examine several flowering plant families. Identify
the features that unify the examples into each family.
For each family you should make careful observations and drawings.
As you examine the plants in the following three labs you are asked to complete a
description of each family. Appendices B (pg 100), C (pg 101), and D (pg 102 - 105)
will be very useful. The class will examine the first family (Rosaceae) as a group to
demonstrate what you are expected to do.
FAMILY ROSACEAE
(a) Flowers:
inflorescence
symmetry
colour
sepals
petals
stamen
pistil
(b) Fruit:
(c) Leaves:
(d) Other General Observations (smell, colour etc):
(e) Uses: perfume (rose), food (berries), ornamental
(hawthorne)
(f) Examples: Fragaria (strawberry), Rosa (rose),
Rubus (blackberry, raspberry, salmonberry), Malus
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(apple), Prunus (nectarine, peach, plum, almond, cherry, peach)
Some uses by BC First Nation's People: There were (and are) a great many plants from this
family used in various ways by the First Nation's People of British Columbia. Many members of the
family produce edible berries. This is particularly true of the genus Rubus (salmonberry, blackberry,
thimbleberry). Face paints were made from Rubus parviflorus (thimbleberry), Crataegus
(hawthorn), and Prunus emarginata (bittercherry) to name a few. The crabapple tree (Malus fusca)
belongs to this family and was important not only for fruit, but also bows. Wood from many of the
tree species was used for making small implements.
BIOLOGY 343
Lab #4
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LAB #4 - FAMILIES: CUCURBITACEAE, SOLANACEAE, AND
BRASSICACEAE
A. FAMILY CUCURBITACEAE (squash, cucumber family)
(a) Flowers:
inflorescence
symmetry
colour
sepals
petals
stamen
pistil
(b) Fruit:
(c) Leaves:
(d) Other General Observations (smell, colour etc):
(e) Uses:
(f) Examples: Citrullus (watermelon), Cucumis
(cantaloupe, cucumber, gherkin, honeydew), Cucurbita
(squash, pumpkin, gourds), Luffa (loofa, vegetable sponge),
Lagenaria (calabash, bottlegourd), Sechium (chayote)
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Lab #4
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Examine a flower of one the plants in this family. Are the flowers bisexual or
unisexual?
Examine the slides of a flower. Find the large nectaries. What is their function?
How would you describe the growth habit of these plants?
What support structures can you see? Are they modified stems or leaves?
Examine the fruit available. What type of fruit do members of this family produce?
Can you identify the layers of the fruit wall? What part(s) of these fruits are edible?
Loofah sponges also called vegetable sponges are made from Luffa cylindrical
(smooth luffa) or Luffa acutangula (ribbed gourd). When harvested young this gourd
can be eaten as a vegetable. If it is permitted to remain on the stalk and mature it
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Lab #4
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becomes very fibrous. Examine a luffa sponge. What accounts for the rough fibrous
texture?
The distribution of bottle gourds (Lagenaria siceraria) is one of the biggest mysteries
confronting phytogeographers and archeologists. There is evidence the species arose
in Africa, but its use in Mexico can be traced back to 7000 BCE. This versatile fruit
has been used for many things ranging from containers, musical instruments, penis
sheaths, pipes, and decoration.
BIOLOGY 343
Lab #4
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B. FAMILY SOLANACEAE (potato or nightshade
family)
Herbs, vines, shrubs, or trees, ~85 genera, 2200 species
(a) Flowers:
inflorescence
symmetry
colour
sepals
petals
stamen
pistil
(b) Fruit:
(c) Leaves:
(d) Other General Observations (smell, colour etc):
(e) Uses:
(f) Examples: Atropa (deadly nightshade), Brugmansia (angel's trumpet), Nicotiana
(tobacco), Physalis (ground cherry, Chinese lanterns), Solanum (nightshade, potato,
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Lab #4
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eggplant), Lycopersicon (tomato), Capsicum (peppers including red, yellow, green,
hot), Hyoscymus (henbane), Petunia, Datura, Mandragora (mandrake)
Some uses by BC First Nation's People: Solanum tuberosum (potato) was introduced to
coastal first peoples by early European seamen. They became an important staple as well as an
article of trade. The Haida were well-known for their potato production and traded them not only
with Europeans, but other first peoples such as the Timshian. Nicotiana quadrivalvis (Indian
tobacco) was also cultivated by many first nations groups. Its natural distribution is unknown as it is
no longer found in the wild. It was chewed often with burned clamshells. It was also mixed with
Kinnickinnick (Arctostaphylos uva-ursi) leaves as a taste additive. The introduction of Nicotiana
tabacum, by European traders, replaced the use of Indian tobacco. Smoking became a popular way
of using it.
Examine and sketch a flower of Petunia. Label.
Examine the tomato flower. These flowers are bee-pollinated by a method called buzz
pollination. The bee hangs upside down and buzzes. The vibrations cause the pollen
to fall onto the bee. The bee therefore gets not only nectar from these plants, but also
pollen (an important protein source for developing larvae).
Examine and draw the fruits of the various members of this family. In what ways are
these fruits similar? In what ways do they differ?
Make a cross-section through the ovary wall of a red bell pepper and investigate with
the microscope where the pigment of the pepper is stored. What tests can you do to
identify the pigment type (hint: we discussed this in lecture).
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Lab #4
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Capsicum peppers (Levetin and McMahon, pages 287 - 289) are the most widely cultivated spices in
the world. They originated in South America and have become the most important component of a
number of cuisines including Mexican, Thai, and Indian. There are five different species and many
varieties. Capsicum annuum includes such varieties as sweet bell peppers, jalapeno, ancho, serrano,
cayenne, and paprika. The earliest evidence of Capsicum cultivation is dated 5,000 years ago in
Mexico where it continues to be an important spice. Capsaicinoids (alkaloids) are the chemicals that
provide flavour and heat (pungency). The surface cells of the placenta produce the compounds.
Capsaicin (the most important of these alkaloids) is secreted to the inner part of the fruit (locule) and
often ends up coating the seeds and inner ovary wall. If you want to reduce the heat of a pepper
when cooking, you should remove the seeds and the placenta. The heat of peppers is often
represented in Scoville Heat Units: the higher the number, the hotter the pepper.
Determining Scoville Heat Units (SHU) – Class Demonstration
To determine the SHU dilutions of an extract of the pepper are made, and five
volunteers sample each extract, which is in sugar solution, until they can just taste the
Capsicum. It is important that the palette is cleaned between each sampling (crackers
and water are provided).
Pepper 1: _____________________________
Volunteer
1:10
1:100
1:1,000
1:10,000 1:100,000
#1
#2
#3
#4
#5
Scoville Units for Pepper 1: _______________________
Pepper 2: _____________________________
Volunteer
1:10
1:100
1:1,000
1:10,000 1:100,000
#1
#2
#3
#4
#5
Scoville Units for Pepper 2: _______________________
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Lab #4
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Compare your results with other peppers
(Levetin and McMahon: Table 17.2, page 288)
Capsicum annuum:
Bell
0 - 600
Cayenne
30,000 – 50,000
Jalapeno
_____________
Paprika
0 – 2,500
Serrano
_____________
Capsicum chinense:
Habanero 80,000 – 150,000
Capsicum frutescens:
Tabasco
30,000 – 50,000
Why was it important to have the same volunteers test both peppers?
What is the function of capsaicin in the plant?
Why is there no absolute Scoville value for each pepper?
Examine a potato. It is a tuber (a modified underground stem). Can you see any
evidence that supports this statement? Why would a plant use such a structure to store
nutrients? What other function(s) do tubers perform?
Many members of this family are poisonous (…stay tuned for Lab #7!). Alkaloids are
commonly found in members of the Solanaceae. Alkaloids are basic organic
nitrogenous compounds that have physiological effects in animals including humans.
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Lab #4
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"Spot Test" for Alkaloids"
A fresh cut in the stem or petiole of three plants was made. The sap was
pressed onto a piece of filter paper. A drop of Dragendorf reagent was applied to the
spot. A red or orange colour indicates the presence of an alkaloid. Which plants have
the strongest reaction to the reagent?
Fig. 4.1 Solanum dulcamara - native to
Europe this plant is now a common weed
around Vancouver. The little flower with its
pretty purple petals has a yellow cone of
stamens.
Its berries look very delicious (shiny and red)
but are actually poisonous (as are its leaves).
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Lab #4
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C. FAMILY BRASSICACEAE = Cruciferae (mustard)
(Levetin and McMahon, pages 293 - 294)
350 genera, 3000 species, Herbaceous
(a) Flowers:
inflorescence
symmetry
colour
sepals
petals
stamen
pistil
(b) Fruit:
(c) Leaves:
(d) Other General Observations (smell, colour etc):
(e) Uses:
(f) Examples: Armoracia (horseradish), Brassica (cauliflower, broccoli, cabbage,
kale, Brussels sprouts, collards, kohlrabi, rape), Capsella (shepherd's purse), Lunaria
(money plant), Rorippa (watercress, nasturtium), Sinapis (yellow mustard), Raphanus
(radish)
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Lab #4
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Broccoli, cauliflower, kohlrabi, cabbage, kale, and Brussels sprouts are varieties of the
species Brassica oleracea (Levetin and McMahon: Fig. 15.3, page 237). Humans
have been cultivating this species since at least 650 BC in the Mediterranean. Briefly
describe each example presented and explain how stems and leaves have been
modified (hint: the original plant is thought to have been kale-like).
Brassica rapa has its origins in the Mediterranean, but a number of varieties arose
elsewhere including the Caucasus (turnip). Many varieties arose in Asia including:
broccoli rabe, Chinese cabbage, bok choi, tatsoi, and mizuna.
Members of this family have very distinctive flowers. Examine the flowers of one of
the specimens. Make note of the different parts of the flower with particular attention
to the petal. Can you identify the structure called a claw?
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Lab #4
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Members of this family have unique fruit types. Silicles are dehiscent fruits from 2
carpellate, 2 chambered ovaries, with the carpels ultimately splitting away from the
membrane (replum) that separates the two locules. The fruit is less than three times
long as wide. The other fruit type is called a silique. In this case the fruit is more than
three times long than wide. Determine the fruit type of the samples available. Sketch
a silique and a silicle.
Crucifers are also characterized by strong flavours (and fragrances) that its members
produce. These chemicals are defensive, but humans have selected and bred for
reduced bitterness and toxicity.
Examine the seeds of mustard. They are important in the making of the condiment
called mustard. They are ground into a powder and mixed with milk, water, or
vinegar. The word mustard comes from the old french "moustarde", which comes
from the latin "mustum" meaning must. This refers to the juice of grapes or other
fruits (generally used for fermentation) to which the mustard seed is mixed.
Horseradish is also made from the grated root of Armoracia rusticana. It has a very
distinctive smell and flavour. Horseradish is often substituted for wasabe (the green
hot stuff you get with sushi). Wasabe (Wasabia wasabi) is also a member of this
family (native to East Asia).
Canola (named for “Canadian oil low acid”) is a cultivar of Brassica napus or B.
rapus, which has been modified to yield edible oil (rapeseed oil). Rape was modified
through breeding to reduce the level of the toxin erucic acid. Since then, canola has
also been genetically modified (herbicide resistance).
Another important member of the Brassicaceae is Arabidopsis thaliana. Its small
genome has been fully sequenced and it is easy to grow in a laboratory setting, making
it an ideal model organism for studies in molecular genetics and development.