- - AGRICULTURAL CORE CURRICULUM - - (CLF300) Core Area: PLANT SCIENCE (CLF310) Unit Title: BASIC BOTANY ____________________________________________________________________________ (CLF311) Topic: PLANT PARTS Time Taught in Year(s) 2 hours 1 ____________________________________________________________________________ Topic Objectives: Upon completion of this lesson the student will be able to: Learning Outcome (A-1) - Identify plant parts including, roots, leaves, stem, fruit, and flower. (A-1) - Describe the general function of each of the above listed plant parts. SPECIAL MATERIALS AND EQUIPMENT: (See "Activities" for details) Have a variety of plant samples available; potted plants with flowers, examples including geraniums; tomatos; for use in tropism examples; clear glass jar or terrarium; bean seeds, and growing media; slide of leaf cross sections; samples of barks; and samples of perfect and imperfect flowers. Evaluation: Quiz by instructor and lab practical for plant part I.D. ================================================================== *** INSTRUCTORS PLEASE NOTE *** Portions of this topic go beyond the scope of the Basic Core and are included for your use as you think appropriate. ================================================================== TOPIC PRESENTATION: PLANT PARTS I. ROOTS: A. Types of root systems: The roots of a plant can be of two basic types. 1 . The FIBROUS root system, such as in corn or beans in which the roots branch from the bottom of the plant; or 2. the TAPROOT where a long tapering root such as in the carrot, dandelions and mesquite, develops. II. PARTS OF THE ROOT SYSTEM A. The main parts of the root include: 1. The ROOT HAIRS (carry on absorption). 2. The ROOT CAP and MERISTEM (involved in growth) are the conducting tissue. (They conduct moisture and nutrients to the plant). The root system develops the primary root, and then branches into secondary roots. ___________________________________________________________ ACTIVITY: A simple experiment can be conducted to show root development along with other growth. Have a clear glass jar, terrarium etc. and fill with growing media. (Growing media can consist of 1/3 perlite, 1/3 peatmoss and 1/3 soil.) Soil should not be used unless you have some kind of sterilization.) Place a bean seed, such as a Lima Bean, against the glass about 1/2 to 3/4 inches below the growing media surface. Have the student make a daily recorded observations. ___________________________________________________________ B. LEAVES 1. The leaf is the food manufacturing factory of the plant which performs (PHOTOSYNTHESIS) and contains the green pigment CHLOROPHYLL which makes the process possible. a. The leaf is composed of (obtain copy master diagrams of plant parts from the California Curriculum Guidelines - Introduction to Agriculture): 1) The STOMATAS are small openings usually on the underside of a leaf which help cool the plant through the TRANSPIRATION of water. 2) The BLADE is the main body of the leaf. 3) The PETIOLE is the stem which attaches the blade to the stem. 4) The MIDRIB like structure is the large central vein down the middle of the leaf. 5) The APEX is the tip of the leaf. 6) The BASE is the bottom of the leaf and attaches to the petiole, or if a petiole is absent, directly to the stem. (A leaf with no petiole is said to be "sessile.") 7) The MARGIN is the edge of the leaf. ___________________________________________________________ ACTIVITY: Have the students observe and draw a simple leaf and a compound leaf, labeling their parts. A simple leaf has a totally intact blade. Compound leafs are divided by the midrib and are composed of several "leaflets". Use the ??? To help students accomplish this, bring to class samples of the following leaves for observation by students: a. Pine b. Sycamore c. Camellia d. Nardina Describe the leaves by color, size, general shape, attachment to be twig, venation, etc. ___________________________________________________________ 2. LEAF TYPES INCLUDE: a. simple leaves, b. compound leaves, and c. needle leaves. 1) Needle leaves are narrow, compact leaves such as pine or fir needles. ___________________________________________________________ ACTIVITY: Prepare slides or use pre-prepared slides of cross-sections, surfaces and undersides of leaves, to observe cell structure. Observe differences in cells under a microscope and have students briefly sketch what they see. ___________________________________________________________ 3. LEAF FUNCTIONS: The leaf is the environmental food factory. a. The leaf captures solar energy, which is converted into chemical energy in the form of sugars and starch and is transferred up the food chain. 4. STEMS a. The stem contains buds (found in the area referred to as the node). b. The stems are the central support structure of the plant. 5. EXTERNAL ANATOMY a. Areas between the buds are called the INTERNODES. Other important parts of the stem are the bark lenticels, leaf scars and scale scars. The terminal growth of a plant occurs at the tips of stems with terminal buds. ___________________________________________________________ ACTIVITY: Bring in a stem such as Black Walnut, remove the leaves and point out the various parts. ___________________________________________________________ 6. INTERNAL ANATOMY: (See California Curriculum Guidelines, Introduction to Agriculture, "Basic Plant Science" for diagrams of the following.) a. The stems inside area, under the sapwood, contains xylem, phloem, cambium, sapwood, heartwood and pith. This surrounds the OUTSIDE of the tree. b. Next comes the xylem and the cambium, then phloem, sapwood, heartwood and in the center of a tree is the pith. c. Herbacious plants have a different structure consisting of epidermis, cortex, pith and a series of vascular bundles. (More information on the function of the stem will be found in other topics in this unit.) 7. FRUIT: a. The fruit of a plant is actually a ripened ovule. In most plants the ovule or egg is fertilized by the sperm (from the pollen) and the ovary matures into the fruit. b. Fruits are usually classified by their structure and number of ovules. c. Simple fruits can be fleshy or dry. They develop from a simple ovary. 1) An example is a berry which is a simple fruit that has a fleshy tissue. Other examples include tomatos and cranberries. (Strawberries and blackberries are not true berries, rather they are "aggregates.") d. A simple fruit with fleshy tissue is classified as a "DRUPE or POME". 1. A drupe has a stone in the center of the fruit which is its seed. Examples of drupes are olives and peaches. 2. Pomes do not have a stone but have several seeds usually within a chamber. Examples of pomes are apples and pears. e. Simple fruits can also be dry, and are further classified as INDEHISCENT or DEHISCENT. 1. Indehiscent fruits are those which split open and release seeds when ripe. Examples are buckwheat, corn and wheat. 2. The second category of simple dry fruit are dehiscent. These split open when ripe and release seeds. Examples are Redbud, Honeysuckle and Forysthia. g. Fruits can be classified as "aggregate" or as "multiple fruit." 1. Aggregate fruits are developed from a single flower with may ovaries. (An example is the blackberry.) 2. Multiple fruit is a classification of fruit with flowers that are separated but closely clustered such as in mulberry, fig and pineapple. 8. FLOWERS: a. The flowers of plants are Nature's wonders. The flower usually contains four main parts: The SEPALS, PETALS, STAMENS AND PISTILS. 1. A flower with all four parts is called a "complete flower." 2. A flower with a STAMEN and PISTIL, the male and female reproductive structures, is said to be a "perfect flower". b. If a flower is missing any of the four primary parts, it is said to be "incomplete." c. If it is missing the stamen or pistil it is said to be "imperfect." d. In a perfect flower, the pistil is the female part of the flower and often is in the center. e. The pistil is composed of 3 primary parts. 1) The pollen collecting structure at the top is called the "STIGMA"; 2) the support structure below the stigma is the "STYLE"; and 3) the enlarged part is the "OVARY," which contains the ovules or eggs. f. The pistil is surrounded by the male stamens which contain the pollen-bearing "ANTHER". g. The anther sits on top of the "FILAMENT" which acts as a stalk to support the anther. ___________________________________________________________ ACTIVITY: Bring in examples of flowers that are perfect, such as a Buttercup, Daffodil and Tulip; imperfects such as Hollies, and Willow; completes such as the Fuchsia; and incompletes such as the Poinsettia and Bottlebrush. ___________________________________________________________ 9. SUPPLEMENTAL: a. Plants classified by flowers and type: 1) Monoecious has male and female flowers on the same plant. 2) Diecious has separate flowers on separate plants. 3) Pistillate has only female parts. 4) Staminate has only male parts. 5) Hermaphroditic has a perfect flower. 12/20/88 sg/gfv