Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Plant Reproduction Chapter 24 Table of Contents Section 1 Sexual Reproduction in Seedless Plants Section 2 Sexual Reproduction in Seed Plants Section 3 Asexual Reproduction

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Plant Reproduction Objectives Summarize the life cycle of a moss. Summarize the life cycle of a fern. Compare and Contrast the life cycle of a moss with the life cycle of a fern. Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Reproduction in Nonvascular Plants Like all plants, nonvascular plants have a life cycle called alternation of generations. The structure that produces eggs is called an archegonium. The structure that produces sperm is called an antheridium. Section 1 Plant Reproduction Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Reproduction in Nonvascular Plants, continued Life Cycle of a Moss A moss sporophyte grows from a gametophyte and remains attached to it. Spores form by meiosis inside the spore capsule. Therefore, as in all plants, the spores are haploid. The spore capsule opens when the spores are mature, and the spores are carried away by wind or water. Section 1 Plant Reproduction Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Life Cycle of a Moss Section 1 Plant Reproduction Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Reproduction in Seedless Vascular Plants Seedless vascular plants can reproduce sexually only when a film of water covers the gametophyte. Some ferns, for example, have sporophytes that are as large as trees. The sporophytes produce spores in sporangia. A cluster of sporangia on a fern frond is called a sorus. Section 1 Plant Reproduction Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Reproduction in Seedless Vascular Plants, continued Life Cycle of a Fern During the life cycle of a fern, a fertilized egg, or zygote, grows into a new sporophyte. The diploid sporophyte produces spores by meiosis. The haploid spores fall to the ground and grow into haploid gametophytes. Section 1 Plant Reproduction Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Life Cycle of a Fern Section 1 Plant Reproduction Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Sexual Reproduction in Seed Plants Objectives Distinguish the male and female gametophytes of seed plants. Describe the function of each part of a seed. Summarize the life cycle of a conifer. Relate the parts of a flower to their functions. Summarize the life cycle of an angiosperm. Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Reproductive Structures of Seed Plants The tiny gametophytes of seed plants develop within specialized structures that form in the reproductive parts of a flower. Section 2 Sexual Reproduction in Seed Plants Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Reproductive Structures of Seed Plants, continued A male gametophyte of a seed plant develops into a pollen grain, which has a thick protective wall. A female gametophyte of a seed plant develops inside an ovule, which is a multicellular structure that is part of the sporophyte. The transfer of pollen grains from the male reproductive structures of a plant to the female reproductive structures of a plant is called pollination. A pollen tube grows from a pollen grain to an ovule and enables a sperm to pass directly to an egg. Section 2 Sexual Reproduction in Seed Plants Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Pollen Grain Formation Section 2 Sexual Reproduction in Seed Plants Chapter 24 stamen filamentanther

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ovule Formation in an Angiosperm Section 2 Sexual Reproduction in Seed Plants Chapter 24 carpel style stigma ovary

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Seeds A seed forms from an ovule after the egg within it has been fertilized. The outer cell layers of an ovule harden to form the seed coat as a seed matures. Leaflike structures called cotyledons, or seed leaves, are a part of a plant embryo. Section 2 Sexual Reproduction in Seed Plants Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Seed Structure Section 2 Sexual Reproduction in Seed Plants Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Parts of a Seed Section 2 Sexual Reproduction in Seed Plants Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Cones The gametophytes of gymnosperms develop in cones, which consist of whorls (circles) of modified leaves called scales. Pollen cones produce large quantities of pollen grains that are carried by wind to female cones. At the time of pollination, the scales of a female cone are open, exposing the ovules. When a pollen grain lands near an ovule, a slender pollen tube grows out of the pollen grain and into the ovule. Section 2 Sexual Reproduction in Seed Plants Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Cones, continued Life Cycle of a Conifer In pines, as in all plants, a diploid zygote results from sexual reproduction. The zygote develops into an embryo, which then becomes dormant (inactive). The embryo and the surrounding tissues form a seed. When their seeds are mature, seed cones open, and the seeds fall out. When conditions are favorable for growth, the seeds grow into new sporophytes. Section 2 Sexual Reproduction in Seed Plants Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Life Cycle of a Conifer Section 2 Sexual Reproduction in Seed Plants Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Flowers Flower parts are arranged in four concentric whorls. The outermost whorl consists of one or more sepals, which protect a flower from damage while it is a bud. The second whorl consists of one or more petals, which attract pollinators. The third whorl consists of one or more stamens, which produce pollen. Section 2 Sexual Reproduction in Seed Plants Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Flowers, continued Each stamen is made of a threadlike filament that is topped by a pollen-producing sac called an anther. The fourth and innermost whorl of a flower consists of one or more pistils, which produce ovules. Ovules develop in a pistil’s swollen lower portion, which is called the ovary. Usually, a stalk, called the style, rises from the ovary. Section 2 Sexual Reproduction in Seed Plants Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Floral Structure Section 2 Sexual Reproduction in Seed Plants Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Flowers, continued Flowers and Their Pollinators Many flowers have brightly colored petals, sugary nectar, strong odors, and shapes that attract animal pollinators. Flowers are a source of food for pollinators such as insects, birds, and bats. Many flowers, such as those of grasses and oaks, are pollinated by wind. Wind-pollinated flowers are usually small and lack bright colors, strong odors, and nectar. Section 2 Sexual Reproduction in Seed Plants Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Flowers and Animal Pollinators Section 2 Sexual Reproduction in Seed Plants Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Flowers, continued Life Cycle of an Angiosperm Following fertilization in an angiosperm, the zygote and the tissues of the ovule develop into a seed, which grows into a new sporophyte. The adult sporophytes of angiosperms produce spores by meiosis. The fusing of three haploid (n) cells forms a triploid (3n) cell that develops into endosperm. This is a process called double fertilization. Section 2 Sexual Reproduction in Seed Plants Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Formation of a Female Gametophyte Section 2 Sexual Reproduction in Seed Plants Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Formation of a Male Gametophyte Section 2 Sexual Reproduction in Seed Plants Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Asexual Reproduction Objectives Summarize the characteristics of organic compounds. Compare the structures and function of different types of biomolecules. Describe the components of DNA and RNA. State the main role of ATP in cells. Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Vegetative Reproduction Plants reproduce asexually in a variety of ways that involve nonreproductive parts, such as stems, roots, and leaves. The reproduction of plants from these parts is called vegetative reproduction. Many of the structures by which plants reproduce vegetatively are modified stems, such as runners, bulbs, corms, rhizomes, and tubers. Section 3 Asexual Reproduction Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Stems Modified for Vegetative Reproduction Section 3 Asexual Reproduction Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu External Structures of Kalanchoë Section 3 Asexual Reproduction Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Internal Structures of Kalanchoë Section 3 Asexual Reproduction Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Plant Propagation Growing new plants from seed or from vegetative parts is called plant propagation. Rhizomes, roots, and tubers can be cut or broken into pieces with one or more buds that can grow into new shoots. In another technique called tissue culture, pieces of plant tissue are placed on a sterile medium and used to grow new plants. Section 3 Asexual Reproduction Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Methods of Vegetative Plant Propagation Section 3 Asexual Reproduction Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice Use the drawing of a plant seed below to answer questions 1–3. Standardized Test Prep Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 1.Which structure is the embryonic root? A.A B.B C.C D.D Standardized Test Prep Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 1.Which structure is the embryonic root? A.A B.B C.C D.D Standardized Test Prep Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 2. Which structure is the source of nutrients for the embryo? F.A G.B H.C J.D Standardized Test Prep Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 2. Which structure is the source of nutrients for the embryo? F.A G.B H.C J.D Standardized Test Prep Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 3. What type of plant produced this seed? A.nonvascular plant B.gymnosperm C.dicot D.monocot Standardized Test Prep Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 3. What type of plant produced this seed? A.nonvascular plant B.gymnosperm C.dicot D.monocot Standardized Test Prep Chapter 24