(i) The thread-like non-reproductive structures in Rhizopus are known as hyphae. (ii) Sporangia develop at the tips of the non-reproductive threads in Rhizopus. (b) In the fungus, Rhizopus, some specialised hyphae give rise to a globular structure (known as sporangium) that contains spores.

The Rhizopus Thread-like Non-Reproductive Structure: Rhizoids

Rhizopus is a common filamentous fungus that belongs to the class Zygomycetes. It is known for its thread-like non-reproductive structures called rhizoids. Rhizoids play a crucial role in the attachment, absorption, and penetration of the fungus into its substrate.

Definition and Characteristics of Rhizoids

Rhizoids are specialized hyphae that arise from the mycelium of Rhizopus. They are root-like structures that extend into the substrate or host organism, providing anchorage and nutrient absorption. Rhizoids are unbranched and appear as fine, thread-like structures.

Functions of Rhizoids

1. Attachment: Rhizoids are responsible for anchoring the Rhizopus mycelium to the substrate. They penetrate the surface and form a network of thread-like structures, ensuring stability and preventing the fungus from being easily dislodged.

2. Absorption: Rhizoids are involved in the absorption of nutrients from the environment. They secrete digestive enzymes, such as amylase and protease, which break down complex organic matter into simpler compounds. The rhizoids then absorb these nutrients, providing sustenance for the growth and development of the fungus.

3. Penetration: Rhizoids can invade the tissues of a host organism, such as fruits or vegetables. The hyphae of Rhizopus grow into the host, aided by the rhizoids, allowing the fungus to obtain nutrients from the living or decaying matter.

Structure of Rhizoids

Rhizoids are composed of elongated cells called hyphae, which are the basic building blocks of fungal structures. The hyphae of Rhizopus are typically multinucleated, meaning they contain multiple nuclei within a single cell.

The cell walls of rhizoids are made of chitin, a complex polysaccharide that provides structural support and rigidity. The chitinous cell walls protect the rhizoids and help maintain their shape during growth and penetration.

Conclusion

Rhizoids are essential structures in the life cycle of Rhizopus. They provide attachment, absorption, and penetration capabilities to the fungus. By anchoring the mycelium, absorbing nutrients, and penetrating host tissues, rhizoids enable the fungus to thrive and complete its life cycle. Understanding the structure and functions of rhizoids is crucial for studying the biology and ecology of Rhizopus.

Hyphae/mycelium