An examination of the organic substrate beneath a mature mushroom (*Agaricus*) reveals an extensive, thread-like subterranean network of hyphae. Which statement accurately describes how this mycelial network functions in the nutrition of the fungus?
- It secretes digestive enzymes into the surrounding substrate to break down organic matter and absorbs the dissolved nutrients.Answer
- BIt ingests solid particulate organic debris via phagocytosis into internal food vacuoles for intracellular breakdown.
- CIt absorbs water and mineral salts to transport them to photosynthetic tissues contained in the mushroom cap.
- DIt functions as a true root system that synthesizes cellulose cell walls while storing excess glucose as starch reserves.
Answer
The mycelial network secretes extracellular enzymes to break down organic matter in the substrate and absorbs the resulting dissolved soluble nutrients.
Members of Kingdom Fungi, such as the mushroom (*Agaricus*), are heterotrophic saprophytes. Their extensive subterranean hyphal network (mycelium) secretes digestive enzymes externally onto decaying organic matter in the substrate. These enzymes digest complex polymers into simple soluble molecules, which are subsequently absorbed across the hyphal membranes.
Step-by-Step Solution
Key Concept
Saprophytic Extracellular Digestion in Fungi