Review land-plant adaptations, fungal nutrition, and partnerships between roots and fungi.
Part of the free Knowledge Mountain biology library. Read an explanation, try a question, and use a memory cue to check what you can recall.
Major plant innovations include protection of embryos, vascular tissue, seeds and pollen, and flowers and fruits. These features arose in different branches over evolutionary time.
Bryophytes lack the vascular tissues found in ferns and seed plants. Ferns have vascular tissue but do not make seeds. Gymnosperms make seeds; angiosperms make flowers and fruits.
How do pollen and seeds help plants live on land?
Pollen transfers the male gametophyte without requiring free-swimming sperm in external water, while seeds protect and nourish an embryo and can aid dormancy and dispersal.
Seed-plant reproduction is less tied to external water than reproduction in mosses and ferns. Seeds contain an embryo, stored food, and a protective covering.
Fungi are heterotrophs that secrete digestive enzymes and absorb the resulting small molecules. Many consist of hyphae, which together form a mycelium. Their cell walls contain chitin.
Many fungi decompose dead material; others are parasites or mutualists. They are more closely related to animals than to plants, despite often growing in place.
In a typical mycorrhizal partnership, what does a plant give a fungus, and what does the fungus help the plant obtain?
The plant supplies sugars or other organic carbon; the fungus helps obtain water and mineral nutrients, especially phosphorus.
Fungal hyphae extend the effective absorptive reach of the root. Both partners can benefit, making the relationship a mutualism.