Seedless Plant Reproduction

1. Seedless Plant Reproduction Chapter 7: Section 2

2. Seedless Plants • How do seedless plants reproduce? • Include all nonvascular plants and some vascular plants • Vascular vs. nonvascular • Nonvascular plants do not have structures that transport substances through the plant • Substances move from cell to cell • Vascular plants have tube-like cells that transport water & substances throughout the plant

3. Nonvascular Plants

4. Importance of Spores • If you want to grow plants (mosses or ferns) that reproduce by spores, can you buy a packet of seeds? • These plants do not reproduce by seeds • Mosses and ferns contain parts called spore cases • Spore cases contain spores; when they break open spores are released – how are they spread?

5. Nonvascular Seedless Plants • Mosses are an example of nonvascular plants • Sporophyte stage of these plants is small and is easily overlooked • Mosses are green, low-growing masses of plants • This is the gametophyte stage (which produces sex cells)

6. Nonvascular Seedless Plants • If you were to look closely at the moss, you might see brown stalks growing up from the tip of the plant • This is the Sporophyte stage • Brown capsules are on tips of plants • Contain millions of spores • When conditions are right, capsule opens and spores fall to ground or are carried by wind • New mosses can grow from each spore & cycle begins again • Figure 6: page 209

7. Nonvascular Plants • Nonvascular plants can also reproduce asexually • If a piece of moss gametophyte breaks off, it can grow into a new plant • Liverworts: form small balls of cells on surface of gametophyte plant; then carried away by water and grow into a new gametophyte plant if they settle in the right environment

8. Vascular Seedless Plants • Millions of years ago most plants were vascular seedless plants • Most are ferns but others include horsetails and club mosses • All of these plants have structures to transport water and nutrients in the plant • The gametophyte stage is small and often over-looked

9. Ferns • Fern plants seen in nature and houses are fern sporophyte plants • Fern leaves are called fronds • Fronds grow from underground stem called rhizomes • Roots that anchor plant also grow from rhizomes • Fern sporophytesmake food by photosynthesis

10. Ferns • Fern spores produced in structures called sori (sorus) usually on underside of fronds • Sori look like crusty, rust-brown bumps • If a fern spore lands on damp soil it can grow into a small, green, heart-shaped gametophyte called a prothallus • Very hard to see because they are very small (5mm-6mm) • Prothallus contains chlorophyll

11. Ferns • Ferns can reproduce asexually, also • Fern rhizomes grow and form branches • New fronds and roots develop from each branch • The new rhizome branch can be separated from the main plant • It can then grow on its own and form more fern plants

12. Section 2: Summary • Seedless plants reproduce by forming _______. • Seedless plants include all nonvascular plants and some vascular plants. • Spores are produced by the sporophyte stage and can grow into gametophyte plants • The sporophyte ________ photosynthesize. • Fern sporophytes have green fronds that grow from underground rhizomes.

13. Review Questions • Describe the life cycle of mosses. • Explain the stages of the life cycle of a fern. • Compare and contrast the gametophyte plant of a moss and the gametophyte plant of a fern. • Describe asexual reproduction in seedless plants. • Why do some seedless plants reproduce only asexually during dry times of the year?