Stages of the Mongo Seed

••• EnlightenedMedia/iStock/GettyImages

Mongo seeds are the familiar white bean sprouts seen in stores and restaurants. They're also known as mung beans, or mungbeans; their taxonomic name is Vigna radiata. They're easy to sprout in the classroom or home, and they illustrate the stages of germinating dicotyledonous seedlings -- dicots for short. Dicots sprout with separate leaves on a stem, unlike single-leaf monocots like grass. Mongos are also epigeal, meaning the seedlings emerge from their seed husks and leave them below ground.

Taking up Water

The first step is to soak the dry beans so they absorb water to begin the germination process. Any beans that float will not be viable. Given a day of soaking, the beans will swell as they take in water. Mung beans more than double their weight, and nearly triple their volume. While the water level in the container doesn't change, the swelling beans take up a greater proportion of the volume.

A Root Emerges

The seed husk, called the testa, swells more quickly than the embryonic seedling inside. The first sign of germination is the emergence of the white root tip called the radicle. Since this growth process requires oxygen, the beans are drained for exposure to air while sprouting. With each day, these roots grow longer. If the beans are sprouted in soil, there's nothing to see yet above the surface while this is happening.

Shedding the Seed Husk

The emergence of the radicle begins the splitting of the testa. Next the plumule -- the plant's first bud -- sheds the testa by growing out of it. This will become the above-ground part of the erect adult plant, beginning with the cotyledons -- the first set of simple, embryonic leaves. Mung beans exhibit epigeal germination, where the testa is left below the soil surface. The plumule is pushed upward by the growth of the radicle, which is also sprouting root hairs to gather moisture and nutrients from the soil.

True Leaves Develop

As the plumule breaks through the soil surface, the cotyledons at its end open to present the first two leaves, making the mung bean a dicot. These embryonic leaves have a simple oval shape, not like the adult plant's true leaves, which will grow later. They hold nutrients from the original seed, to feed the development of the first true leaves. As the leaves develop, the cotyledons wither, and the young plant has left its seedling stage.

Related Articles

Fastest Growing Plants for a Science Project
Sequence of Steps in Monocot & Dicot Germination
The Parts of a Wheat Plant
What Is the Function of the Cotyledon in the Seed?
Three Main Parts of a Seed
What Type of Bean Seeds to Use for a Science Experiment
The Importance of Water in Seeds Germination
The Fastest Growing Plants for Science Experiments
Characteristics of a Carrot Plant
How to Count Jelly Beans in a Jar
How to Explain the Life Cycle of a Plant
How Does the Venus Flytrap Reproduce?
The Life Cycle of a Rose Plant
Plants Found in Lakes & Ponds
Plants Which Reproduce Through Leaves
Science Fair Projects About Growing Beans and the Life...
How to Grow a Potato in Water for a Science Project
What Advantages Do Seeds Have Over Spores?
Six Basic Parts of a Plant
Which Seeds Will Germinate the Fastest for a Science...

Dont Go!

We Have More Great Sciencing Articles!