PLANT CLASSIFICATION (Levetin and McMahon, pages 123 – 138). Although
scientific names can be pretty incomprehensible to the layperson they.
BIOLOGY 343 – PLANTS AND PEOPLE SUMMER 2010 Date
Labs and Field Trips
Field Trip: Pacific Spirit Park
Lab #1: Plant Structure I
Lab #1: Plant Structure I (Quiz #1)
Library Orientation: Meet in lecture (Quiz #2) Lab #2: Plant Structure II (afternoon)
Field Trip: Arboretum Tour (am)
Lab #3: Plant Reproduction (Quiz #3)
Lab #4 – Plant Families I
Guest Lecture (not optional): Plants to Dye For Optional Lab Activity: Plants to Dye For (afternoon)
Lab #5 – Plant Families II (Quiz #4)
Optional Fieldtrip: UBC Farm (morning) Lab #6 – Plant Families III (afternoon)
Optional Fieldtrip: Chinatown
Optional Fieldtrip: Anthropology Museum
Lab #7 – Medicinal and Poisonous Plants, Spices, etc (Quiz #5)
July 27 (Tues)
Optional Fieldtrip: UBC Botanical Garden
Lab Final Exam (am)
July 28 - 30
Optional Fieldtrip: Brewery Tour
Front Cover by Kate Saunders
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.
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
(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.
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):
(f) Examples: Citrullus (watermelon), Cucumis (cantaloupe, cucumber, gherkin, honeydew), Cucurbita (squash, pumpkin, gourds), Luffa (loofa, vegetable sponge), Lagenaria (calabash, bottlegourd), Sechium (chayote)
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
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.
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):
(f) Examples: Atropa (deadly nightshade), Brugmansia (angel's trumpet), Nicotiana (tobacco), Physalis (ground cherry, Chinese lanterns), Solanum (nightshade, potato,
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).
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: _______________________
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.
"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).
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):
(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)
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?
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.