Copyright Pearson Prentice Hall Biology Copyright Pearson Prentice Hall

22–3 Seedless Vascular Plants Photo Credit: ©Terry Donnelly/Dembinsky Photo Associates Copyright Pearson Prentice Hall

Evolution of Vascular Tissue 420 million years ago, moss-like plants on land were joined by taller plants. Evidence shows that these plants had vascular tissue, which is specialized to conduct water and nutrients throughout the plant. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Vascular Evolution Copyright Pearson Prentice Hall

Evolution of Vascular Tissue The first vascular plants contained tracheids which are cells specialized to conduct water. Tracheids make up xylem, a transport subsystem that carries water from the roots to every part of a plant. Copyright Pearson Prentice Hall

Evolution of Vascular Tissue Vascular plants have a second transport subsystem composed of vascular tissue called phloem. Phloem transports solutions of nutrients and carbohydrates produced by photosynthesis. Minerals H2O CO2 O2 Sugar Light Xylem Phloem Copyright Pearson Prentice Hall

Evolution of Vascular Tissue How is vascular tissue important to ferns and their relatives? Both xylem and phloem can move fluids through the plant body, even against the force of gravity. Copyright Pearson Prentice Hall

Ferns and Their Relatives Seedless vascular plants include: club mosses horsetails ferns Copyright Pearson Prentice Hall

Ferns and Their Relatives The most numerous phylum is the ferns. Ferns and their relatives have true roots, leaves, and stems. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Life Cycle of Ferns Ferns have vascular tissues, strong roots, underground stems called rhizomes, and leaves called fronds. Photo credit: ©Peter Chadwick/Dorling Kindersley Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Life Cycle of Ferns Life Cycle of Ferns Ferns and other vascular plants have a life cycle in which the diploid sporophyte is the dominant stage. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Life Cycle of Ferns Fern sporophytes develop haploid spores on the underside of their fronds in structures called sporangia. Sporangia are grouped into clusters called sori. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Life Cycle of Ferns The Underside of a Fern Frond Sporangia Photo Credit: left: ©Biophoto Associates/Photo Researchers, Inc.; right: ©Ed Reschke/Peter Arnold, Inc. Sorus Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Life Cycle of Ferns Fern Life Cycle Sporangium (2N) Frond Young gametophyte (N) Spores (N) Mature sporophyte (2N) Developing sporophyte (2N) Mature gametophyte (N) Antheridium In the life cycle of a fern, the dominant and recognizable stage is the diploid sporophyte. The tiny, heart-shaped gametophyte grows close to the ground and relies on dampness for the sperm it produces to fertilize an egg. The young sporophyte grows from the gametophyte. Sperm Gametophyte (N) Egg Sporophyte embryo (2N) Archegonium Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Fern Gametophyte Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 22–3 Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 22–3 Plant cells specialized to conduct water are called tracheids. veins. sori. phloem. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 22–3 The presence of vascular tissue enables a plant to carry on photosynthesis. carry on lactic acid fermentation. conduct water and nutrients. make chlorophyll. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 22–3 Ferns are different from mosses because they carry out photosynthesis using chlorophyll. have vascular tissue to conduct water and nutrients. help expose more of the plant’s surface area to sunlight. exchange carbon dioxide and oxygen with the atmosphere. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 22–3 Club mosses and horsetails are similar to ferns because they have vascular tissue. seeds. sori. fronds. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 22–3 When fern spores germinate, they develop into diploid gametophytes. haploid gametophytes. haploid sporophytes. diploid sporophytes. Copyright Pearson Prentice Hall

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