Table of Contents

Ergastic Meaning

A plant cell is composed of both living and non-living protoplasmic contents. The non-living protoplasmic contents that are found in the cell wall, vacuoles, and protoplasm are called ergastic substances of the plants. They may be organic or inorganic in nature and may be present in soluble or insoluble form.

Ergastic substances are usually raw materials or products of metabolism that helps the organism in maintenance of cellular structure, defense or as simply a storage substance.

Types of Ergastic Substances

Ergastic substances of plants exist in three forms:

1. Reserve Materials
2. Secretory Materials
3. Waste Products or Excretory Materials

Reserve Materials

Reserve materials are non-protoplasmic contents of the plant cells that serve as storage sites for the plants. They are directly related to the nutrition of the plants. The ergastic reserve materials are of following types:

Carbohydrates

Reserve of carbohydrates is obtained as an end product of photosynthesis. Sugars such as glucose, fructose and sucrose are the simplest form of carbohydrates found in plant cells. Cellulose is another important carbohydrate found in plants that makes up the cell wall of plants.

Starch or starch grains are reserve food materials that are found in almost all plant groups in the protoplasm. They are converted into simple sugars when required. Glycogen is another important reserve food material that is found in fungi.

Nitrogenous Molecules

Although proteins are living inclusions of the protoplasm, some may exist as inactive ergastic bodies in either crystalline or amorphous form. Gluten is an amorphous ergastic protein that is found in cereal grains such as wheat.

Aleurone grains are another example of nitrogenous matter found in the endosperm of plants. They serve as the reservoir of amino acids for plant growth during germination as well as for humans and animals feeding on it.

Oils and Fats

Fats and oils are composed of carbon, hydrogen and oxygen. Fats when found at ordinary temperatures become oil. In plants, fats are usually found in the form of suberin, waxes and cutin that form protective layers in the plant cell.

Secretory Materials

The secretory materials are not food materials but are secretions in the plant cell that are essential for its proper functioning. Chlorophyll, carotenoids and xanthophyll are secretory ergastic materials that are important for photosynthesis and synthesis of food.

Enzymes are other secretory ergastic materials found in plant cells that convert complex macromolecules into simple sugars, proteins and fats.

Excretory Materials

Plants do not have a specific excretory system such as animals. They excrete the waste products in the form of tannins, alkaloids, latex, mineral crystals and essential oils.

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Also Read:

• Difference between Cytoplasm and Protoplasm
• Getting to Know Plants – Parts & Life Cycle of Plants
• Plant Cell – Definition, Structure, Function, Diagram & Types
• How are Plants Important to Humans