Get ready to take Quiz #2 over Chapter 22-25 “Plant Structure and Function” Materials you will need: One piece of paper A writing utensil

Instructions Remove everything from your table except your materials. Fold your notebook paper “hot dog” style. Keep the folded paper closed and turn it where you can see the three holes. Write your full heading starting with the first line. Note: This is the only place your name will be written. Open your paper and write the title “Quiz #2.” Number your paper from 1-10. Write the correct answers for the following questions.

Leaves grow from the stem at the _____. Question #1 Leaves grow from the stem at the _____.

Question #2 Blade Leaf _____ Stem

Vascular Plants are composed of three basic types of tissue: Question #3 Vascular Plants are composed of three basic types of tissue: Name one out of the three.

Question #4 Opposite Whorled Alternate Choose the type of leaf arrangement on the stem shown: Opposite Whorled Alternate

Question #5 Opposite Whorled Alternate Choose the type of leaf arrangement on the stem shown: Opposite Whorled Alternate

Question #6 Simple or Compound?

Question #7 Simple or Compound?

Question #8 Monocot or Dicot?

Question #9 Monocot or Dicot?

Question #10 If human loose some water by perspiration, how do plants loose 90% of the water they take in?

Follow the directions of your teacher. The End of Quiz #2 Follow the directions of your teacher.

Plants

Plant Growth and Development Chapter 22-25

Plant Growth and Development How Plants Grow and Develop Regulating Growth and Development Chapter 25 p. 569

How Plants Grow and Develop A seed germinates when the dormant embryo within the seed resumes growing.

Primary and Secondary Growth Primary growth is produced at apical meristems located at the tips of shoots and roots. Secondary growth is produced at lateral meristems that form from primary stem tissues.

Plant Development Plants develop continuously as new cells form and differentiate. Plant development is considered reversible because cells of certain tissues can produce unspecialized cells that then differentiate into all of the mature plant’s tissues.

**Three Types of Plants** Depending on how long they live, plants can be classified as one of three types. Annuals Biennials Perennials

Annuals Complete their life cycle in one growing season

Biennials Complete their life cycle in two growing seasons

Perennials Live from one growing season to another Have secondary growth Phloem cells develop to the outside Xylem cells develop to the inside Annual rings are produced (can be used to determine age) Wood is secondary xylem tissue. Heartwood – center wood that no longer transports water Sapwood – still functioning wood surrounding the heartwood

Regulating Growth and Development Plants use photosynthesis to produce all of their organic molecules, but require several inorganic nutrients to convert carbohydrates to other important organic molecules. Plant growth and development is regulated by hormones. Plant hormones are produced in response to stimuli from the environment. Therefore, plant growth and development respond to the environment in many ways.

FLOWERS

**Parts of a Flower**

Parts of a Flower

Parts of a Flower Flowers typically are composed of four parts, or whorls, arranged in concentric rings attached to the tip of the stem. From innermost to outermost, these whorls are the (1) pistil (2) stamens (3) petals (4) sepals

Pistil The innermost whorl, located in the center of the flower, is the female reproductive structure, or pistil. Often vase-shaped, the pistil consists of three parts: the stigma, the style, and the ovary.

Stigma The stigma, a slightly flared and sticky structure at the top of the pistil, functions by trapping pollen grains. Pollen grains are the structures that give rise to the sperm cells necessary for fertilization.

Style The style is a narrow stalk that supports the stigma.

Ovary The style rises from the ovary, a slightly swollen structure seated at the base of the flower. Depending on the species, the ovary contains one or more ovules, each of which holds one egg cell. After fertilization, the ovules develop into seeds, while the ovary enlarges into the fruit. If a flower has only one ovule, the fruit will contain one seed, as in a peach. The fruit of a flower with many ovules, such as a tomato, will have many seeds. An ovary that contains one or more ovules also is called a carpel, and a pistil may be composed of one to several carpels.

Stamens The next whorl consists of the male reproductive structures, several to many stamens arranged around the pistil. A stamen consists of a slender stalk called the filament, which supports the anther, a tiny compartment where pollen forms.

Stamens When a flower is still an immature, unopened bud, the filaments are short and serve to transport nutrients to the developing pollen. As the flower opens, the filaments lengthen and hold the anthers higher in the flower, where the pollen grains are more likely to be picked up by visiting animals, wind, or in the case of some aquatic plants, by water. The animals, wind, or water might then carry the pollen to the stigma of an appropriate flower.

Petals Petals, the next whorl, surround the stamens and collectively are termed the corolla. Many petals have bright colors, which attract animals that carry out pollination, collectively termed pollinators.

Pollinators Flowering plants use wind, insects, bats, mammals, and birds to transfer pollen from the stamen, or male portion of the flower, to the stigma, or female portion of the flower. Many plants have evolved closely with certain animals to ensure successful transfer of pollen. For example, many species of rain forest plants can only be pollinated by one particular species of insect, bird, or bat.

Worker Honey Bee in the Field As they fly from flower to flower, worker honey bees collect pollen grains and pack them onto their hind legs in special hair-fringed pockets known as pollen baskets (shown here holding a glob of yellow pollen on the hind leg). Nectar, the sweet liquid produced by flowers, is sucked into the honey stomach, an internal storage sac. In the hive, field bees deposit their pollen pellets into empty storage cells of the comb and regurgitate nectar to waiting hive bees. The hive bees mix some nectar with the pollen to make bee bread, a spoilage-proof larval food, and gradually concentrate the rest of the nectar into honey by dehydration.

Butterfly Pollinating a Flower Many species of butterflies eat plant nectar. When these butterflies land on a series of flowers in search of food, they brush their bodies against both male and female floral organs, inadvertently transferring pollen from one flower to another.

Australian Honey Possum The Australian honey possum is one of the only mammal species, other than bats, known to eat nectar and pollen as the mainstay of its diet.

Brazilian Birthwort The Brazilian birthwort uses insects as pollinators. The putrid odor of this species—like that of rotting flesh—especially attracts flies, which enter the plant and become trapped overnight. While they are trapped, they become completely dusted with pollen. They escape the following day as the plant withers and are attracted to other Brazilian birthworts, which they then inadvertently pollinate as they enter and again become trapped.

Lawson Cypress Branch The Lawson cypress, like all other coniferous trees, is wind pollinated. The tiny male "flowers" are located at the ends of the small branchlets, where the wind can easily pick up and distribute their pollen.

Sepals The sepals, the outermost whorl, together are called the calyx. In the flower bud, the sepals tightly enclose and protect the petals, stamens, and pistil from rain or insects. The sepals unfurl as the flower opens and often resemble small green leaves at the flower's base. In some flowers, the sepals are colorful and work with the petals to attract pollinators.

Pollination The placement of pollen on the stigma is called pollination. Pollination initiates the process of fertilization.

Flower Pollination and Fertilization

Flower Pollination and Fertilization Flowers contain the structures necessary for sexual reproduction. The male component, or stamen, consists of a thin stalk called the filament, capped by the anther. The female component, the carpel, includes the stigma, a sticky surface that catches pollen; the ovary, which contains the ovule and embryo sac with its egg; and the style, a tube that connects the stigma and ovary (A).

Flower Pollination and Fertilization Pollen is produced in the anther (B), and is released when mature (C). Each mature pollen grain contains two sperm cells. In self-pollinating plants, the pollen lands on the stigma of the same flower, but in cross-pollinating plants—the majority of plants—the pollen is carried by wind, water, insects, or small animals to another flower.

Flower Pollination and Fertilization If the pollen attaches to the stigma of a flower from the same species, the pollen produces a pollen tube, which grows down the neck of the style, transporting the sperm to the ovule (D). Within the embryo sac of the ovule, one sperm cell fertilizes the egg, which develops into a seed. The second sperm cell unites with two cells in the embryo sac called polar nuclei, and this results in the development of the endosperm, the starchy food that feeds the developing seed. The ovary enlarges (E) and becomes a fruit.

Pollen Grains A pollen grain contains a sperm cell that fertilizes an egg. If fertilization is successful, a seed is produced. The pollen grains of each species display unique sculpting of the pollen wall, and fossilized pollen serves to identify ancient species. The pollen grains shown here are about 1000 times their actual size.

Pinecone Cones are specialized seed-bearing structures found in a variety of plants including trees such as firs, cedars, pines, cypress, and spruces. The seeds develop on the surface of the cone scales, rather than within a fruit as in flowering plants. In the pine tree the developmental period may take as long as three years. Shortly after the seeds mature, the protective scales of the cone open up, and the seeds are released.

Amaryllis Many plants such as the Amaryllis produce large, brightly colored flowers to attract pollinators. The white streaks on the petals serve to guide insects to the nectar glands located at the center of the flower. Viewed under ultraviolet light, which bees can see, the petal colors are even more striking and the guides highly visible.

Wind Pollination Wind-pollinated plants such as corn typically produce inconspicuous flowers, rather than the brightly colored flowers designed to attract insects. In corn, the male and female parts of the flower are found on different parts of the plant. Shown here are the light green stamens (also called tassles), the pollen-bearing, structures located at the top of the plant. The female structures, which contain very long styles called silks, are growing laterally from the stalk below the stamens.

Flower Types Like virtually all forms in nature, flowers display many variations in their structure. Most flowers have all four whorls—pistil, stamens, petals, and sepals. Botanists call these complete flowers. But some flowers are incomplete, meaning they lack one or more whorls.

Incomplete flowers Incomplete flowers are most common in plants whose pollen is dispersed by the wind or water. Since these flowers do not need to attract pollinators, most have no petals, and some even lack sepals. Certain wind-pollinated flowers do have small sepals and petals that create eddies in the wind, directing pollen to swirl around and settle on the flower.

Imperfect Flowers Flowers that lack either stamens or a pistil are said to be imperfect. The petal-like rays on the edge of a sunflower, for example, are actually tiny, imperfect flowers that lack stamens. Imperfect flowers can still function in sexual reproduction. A flower that lacks a pistil but has stamens produces pollen, and a flower with a pistil but no stamens provides ovules and can develop into fruits and seeds.

Types Of Inflorescences Sometimes flowers are grouped together in a cluster called an inflorescence. Each type of inflorescence is identified by the arrangement of flowers on a stalk.

Don’t forget to study for your Chapter 22-25 “Plant Growth and Development” Quiz #3 When? THE FIRST OF NEXT CLASS