Difference Between Rhizoids and Rhizomes

Main Difference – Rhizoids vs Rhizomes

Rhizoids and rhizomes are two root structures in plants. The main difference between rhizoids and rhizomes is that rhizoids are root-like structures found in primitive plants and fungi whereas rhizomes are partially underground bundles of stems and roots of higher plants. The plant body of primitive plants such as mosses, liverworts, and hornworts is not differentiated into stem, root, and leaves. Therefore, rhizoids serve as the root and attach the plant to the substrate. These primitive plants do not possess a vascular system as well. However, some of the rhizoids absorb water for the plant. Higher plants develop a vascular system as well as a differentiated plant body into stem, root, and leaves. Rhizomes of the ferns produce rhizoids to absorb water and minerals from the soil.

Key Areas Covered

1. What are Rhizoids
      – Definition, Characteristics, Function
2. What are Rhizomes
      – Definition, Characteristics, Function
3. What are the Similarities Between Rhizoids and Rhizomes
      – Outline of Common Features
4. What is the Difference Between Rhizoids and Rhizomes
      – Comparison of Key Differences

Key Terms: Angiosperms, Bryophyta, Ferns, Fungi, Gametophyte, Hyphae, Rhizoids, Rhizomes, Stems, Vegetative Propagation

What are Rhizoids

Rhizoids are root-like structures of bryophytes and fungi. They help in absorption of water and minerals from the soil. Rhizoids anchor the plant body to the substrate as well. The plant body of the primitive plants is not differentiated into stem, root, and leaves. Therefore, rhizoids serve as the root in primitive plants such as mosses, liverworts, and hornworts. The rhizoids of the liverworts are unicellular. In contrast, the rhizoids of the mosses are multicellular. Since the prominent life stage of the primitive plants is the gametophyte, rhizoids occur in the gametophyte. The root hairs of the vascular plants can also be considered as rhizoids. Rhizoids of bryophytes are shown in figure 1.

Figure 1: A bryophyte
r – Rhizoids, s – Sporangium

Rhizoids are also found in fungi. Fungal rhizoids are small branching hyphae that grow downwards of the stolons, anchoring the fungal hyphae to the substrate. They secrete digestive enzymes on the food material and absorb the nutrients.

What are Rhizomes

Rhizomes are the horizontal, underground stems of higher plants. Rhizomes are capable of producing both shoots and roots from it. That means rhizomes are involved in the vegetative propagation, which is one of the asexual reproduction methods in plants. Plants like poplars and bamboos highly rely on rhizomes for their reproduction. Rhizomes store both carbohydrates and proteins. This is important for the survival of the plant under unfavorable environmental conditions. Moreover, these food-storing rhizomes are consumed as food by animals as well as humans.

Difference Between Rhizoids and Rhizomes

Figure 2: Turmeric Rhizomes

Turmeric, ginger, lotus, potato, carrot, and sweet potato are some examples of edible rhizoids. In some plants like ferns and water lilies, the rhizome is the only stem of the plant. The turmeric rhizomes are shown in figure 2.

Similarities Between Rhizoids and Rhizomes

Both rhizoids and rhizomes are related to roots of plants.
Both rhizoids and rhizomes absorb water and mineral from the soil.
Ferns contain both rhizoids and rhizomes.

Definition

Rhizoids: Rhizoids are root-like structures found in primitive plants and fungi.

Rhizomes: Rhizomes are continuously growing, horizontal, underground stems from which the lateral and adventitious roots are developed.

Type of Plants

Rhizoids: Rhizoids are found in primitive plants such as mosses, liverworts, and hornworts.

Rhizomes: Rhizomes are found in vascular plants.

Stem/Root

Rhizoids: Rhizoids are root-like structures.

Rhizomes: Rhizomes are specialized stems that occur underground.

Unicellular/Multicellular

Rhizoids: Rhizoids can be unicellular or multicellular.

Rhizomes: Rhizomes are multicellular.

Function

Rhizoids: Rhizoids absorb water and minerals from the soil.

Rhizomes: Rhizomes store food and help in vegetative propagation of plants.

Conclusion

Rhizoids and rhizomes are two root-related structures found in plants. Rhizoids are found in fungi, bryophytes, and the ferns. Vegetative body of fungi and bryophytes are not differentiated into root, stem, and leaves. Therefore, the functions of the root are carried out by rhizoids. Rhizomes are the underground stems of the higher plants. They store food and are involved in the vegetative propagation. The main difference between rhizoids and rhizomes is the structure and function of each structure in plants.

Reference:

1. “Rhizoids: Definition & Function.” Study.com, Available here. Accessed 8 Sept. 2017.
2. “Rhizome.” Encyclopædia Britannica, Encyclopædia Britannica, inc., 18 Dec. 2014, Available here. Accessed 8 Sept. 2017.

Image Courtesy:

1. “Bryophyta 7” (Public Domain) via Commons Wikimedia
2. “Curcuma longa roots” By Simon A. Eugster – Own work (CC BY-SA 3.0) via Commons Wikimedia