Rhizome
Rhizome and Tuber are both modified stems of a plant and store food but they are both different from each other in many ways. The experts at Vedantu have created a summary of the difference between rhizome and tuber for the students of Biology. Let’s look in detail at these two parts of the plant first.
Rhizomes are underground and horizontal stems that have fleshy, non-green, and distinct nodes and internodes. Rhizomes resemble the root of a plant. They are brownish because they are away from the sunlight. Rhizomes have terminal buds and they run parallel to the ground. New plants can sprout from the buds on a rhizome. They are also known as root stalks and the rhizome root stalk grows vertically upwards. Some common examples of rhizomes are ginger and Alocasia indica
What are the Major Types of Rhizomes?
The rhizomes are mainly of two types, dense rhizomes, and running rhizomes. Dense rhizomes are the ones that grow vertically as roots are produced on the lower side and the shoots grow vertically upright from the nodes whereas running rhizomes are the ones that grow horizontally and can grow underground, subterranean, or above the soil. The horizontal growth is because of the fact that the roots and shoots in running rhizomes grow from the nodes only. Dense rhizomes have short internodes while the long internodes are present in running rhizomes. An example of a dense rhizome is ginger while the example of a running rhizome is bamboo.
What are the Characteristics of Rhizomes?
The main characteristics of rhizomes include:
They allow plants to reproduce through asexual reproduction as well. Plants having rhizomes like ginger and bamboo reproduce through asexual reproduction, that is, vegetative propagation only.
Usually, water plants contain a single stem (rhizome) which is hidden beneath the leaves and flowers.
Rhizome stores food in the form of starch, for example, ginger and turmeric.
These rhizomes store food, thereby, ensuring the growth, development, and survival of plants in adverse winter conditions.
Some rhizomes store energy in the form of starch and sugar grows beneath the ground and has thicker stems as compared to the other rhizomes growing above the ground.
Rhizomes also aid in protecting the perennial plants by providing them with energy throughout the winters.
The advanced stems may have weed characteristics that spread it throughout the place with rapid growth.
Examples of Rhizomes
Rhizomes are majorly of three types, the underground rhizomes, the rhizomes above the ground, and multi-layered rhizomes.
Underground stem rhizomes are very common and are majorly consumed by humans, for example, bamboo, ginger, grass species, hops, and poison oak.
Above the ground rhizomes are the ones that grow close to the soil but not underneath the soil, for example, ferns and irises.
The multi-layered stem system of rhizomes forms both roots and shoots in several layers from the nodes. Such plants have whorls and different layers of leaves, for example, giant horsetails.
Are Rhizoids and Rhizomes the Same Thing?
No, though the words sound very similar the rhizoids and rhizomes are not the same things. Rhizoids are a part of fungi and non-flowering plants like liverworts, hornworts, and mosses. Rhizomes refer to the modified stems that are grown in a horizontal manner continuously and are generally present underground. Rhizoids can either be unicellular or multicellular but rhizomes are only multicellular. The major function of rhizoids is to absorb nutrients, minerals, and water from the soil whereas the major function of rhizomes is to store food in the form of starch and aid in the vegetative reproduction of the plant. Rhizoids are present in most non-vascular plants like algae and bryophytes whereas rhizomes are present in vascular plants only.
Tubers
Although ‘tuber ‘ is a term that generally denotes any fleshy part, in this case, tubers are the fleshy stem of the plant that stores food. In other words, they are the underground part of the branches that become swollen because of the food that gets stored in them. Unlike rhizomes, tubers grow vertically underground. One of the most common examples of a tuber is a potato that is also used as food. Tubers have several depressions called the eyes and they act as nodes for the tuber. Most tubers are spherical, oval, or oblong.
Let’s See Some of the Other Points of Difference Between Tuber and Rhizome
FAQs on Difference Between Rhizome and Tuber
1. How does a rhizome grow into a new plant?
Rhizomes are the thick underground stems of a plant. They grow horizontally and parallel to the ground. They have short internodes and roots growing from the bottom of the nodes. This generates new shoots that grow upwards from the top of the nodes. When a rhizome is separated from the plant, each piece can grow into a new plant. A rhizome is used to store proteins, starches, and other nutrients by the plant. When new shoots are formed or the parent plant dies in winters, these nutrients become useful for the plant. This process is known as vegetative reproduction and is another way for rhizomes to produce offspring.
2. What are the two types of tubers?
Tubers are classified into two types: stem tuber and root tuber. Root tuber is a modified lateral root that functions as a food storage unit for the plant. The storage root which is the enlarged area of the root-tuber is produced at the end or middle of a root. Sometimes it is an entirely new root. A root tuber is similar in function and appearance to a stem tuber but different in its origin. Some common examples of plants with tuberous roots are cassava, sweet potato, and dahlia.
Stem tubers are formed from thickened stolons or rhizomes. They are formed at the sides of the parent plant and are located near the surface of the soil. The underground stem tuber stores food for a short time and develops from a shoot branching from a mature plant. Some common examples of stem tubers are yams, tuberous begonia, and cyclamens.
3. What are some common examples of rhizome and tuber that are used as food?
There are various examples of rhizome and tuber that can be used as food for the consumption of human beings. Rhizomes refer to the horizontal underground stem which is non-green and fleshy, for example, ginger and banana. Tubers refer to the fleshy part of the plant that stores food. The most common example of a tuber is a potato. Some common examples of rhizome used as food are ginger and turmeric and some common examples of tuber used as food like yams, sweet potatoes, and potatoes.
4. What are the functions of rhizomes?
Rhizomes perform various primary and secondary functions that help in the better growth and development of plants. These functions performed by rhizomes are:
Rhizomes store food in the form of nutrients, that is, proteins, carbohydrates, and minerals so that the plant can survive the harsh environmental conditions.
The rhizomes also help plants to utilise these nutrients during reproduction in the form of vegetative propagation to ensure that the plant growth is stable during the winters as well.
The rhizomes are one of the best sources of food for living beings, for example, ginger, spices, and turmeric.
The apical part of rhizomes has energy stored in it to facilitate the growth of plants at low temperatures as well. In other words, the metabolic functioning and rapid growth of the rhizome help the plants to survive winters.
5. Are tubers and tuberous roots the same thing?
No, though tubers and tuberous words are often used interchangeably, these two are different modifications of the plant and do not resemble the same thing. The major difference between tuber and tuberous roots is that we can cut tubers to make a new plant, while tuberous roots usually propagate through cell division. Plants with tubers are short-lived which is not a problem because tubers are harvested fresh for eating purposes. Tuberous roots usually grow in the form of clusters under the surface of the soil, therefore, they are long-lived and are grown mostly for ornamental purposes.
