Properties of food substances

Storage organs in plants

Plants store food to ensure survival during unfavorable conditions and to support growth and reproduction. The stored food can be located in various parts of the plant:

• Leaves – e.g. Onions, Cabbage
• Fruits – e.g. Mango, Pineapple, Pawpaw
• Seeds – e.g. Beans, Peas, Rice, Maize
• Stems – e.g. Irish Potato, Ginger, Sugar Cane
• Roots – e.g. Sweet Potato, Cassava, Carrots

Advantages of food storage organs

1. Support Reproduction: Some storage organs give rise to new plants, e.g. seeds and stem tubers.
2. Survival in Harsh Conditions: Storage allows the plant to survive through dry seasons or other unfavorable conditions.
3. Source of Food: Many storage organs are edible and used by humans and animals for food, e.g. rice, wheat, potatoes.
4. Support Germination: The stored food is used to nourish the plant embryo during germination until leaves develop.
5. Economic Importance: Some are cultivated and sold commercially, e.g. sugar cane.

Mineral requirements in plants

Plants need minerals for proper growth and development. These minerals are grouped into:

i. Macro elements (macronutrients)

These are needed in large amounts and include:

• Carbon (C)
• Hydrogen (H)
• Oxygen (O)
• Nitrogen (N)
• Phosphorus (P)
• Potassium (K)
• Calcium (Ca)
• Sulphur (S)
• Magnesium (Mg)

Functions:

1. Carbon, hydrogen, and oxygen are used in synthesizing carbohydrates.
2. Nitrogen is essential for protein and chlorophyll formation.

ii. Micro elements (micronutrients)

These are needed in small amounts and include:

• Manganese (Mn)
• Zinc (Zn)
• Sodium (Na)
• Boron (B)
• Chlorine (Cl)
• Copper (Cu)
• Cobalt (Co)
• Silicon (Si)

Deficiency Effects:

• Lack of minerals can lead to yellowing of leaves, stunted growth, and poor overall plant health.