Seedless Plant Reproduction Chapter 7: Section 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

Nonvascular Plants

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?

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)

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

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

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

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 sporophytes make food by photosynthesis

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

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

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.

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?