3.3 - Diversity in Plant Nutrition

• Nutrition: process by which organisms obtain energy and nutrients from food for growth, maintenance and repair of damaged tissues.
• Parasitic, epiphytic and carnivorous plants have different adaptations to obtain nutrients.

Nutritional Adaptations of Plants

Parasitic Plants

• Live by growing on other plants called hosts.
• Roots absorb organic substances, minerals and water from the host by penetrating its stem up to its vascular bundles.
• The parasite grows faster and flourishes; the host becomes malnourished, dries and eventually dies.
• Example: Rafflesia sp.

Epiphytic Plants

• Green plants that live on other plants called hosts.
• Receive more sunlight for photosynthesis by living on taller hosts.
• Synthesise their own food.
• Do not harm the host; roots absorb nutrients accumulated in gaps in the host’s stem.
• Most have swollen stems that store large amounts of water.
• Examples: Asplenium nidus (bird’s nest fern) and Bulbophyllum sp. (orchid).

Carnivorous Plants

• Synthesise their own food by carrying out photosynthesis.
• Secrete nectar and have cups that trap prey, typically insects.
• Digest prey slowly using digestive enzymes.
• Trapped animals supply nitrogen required for growth.
• Live in soil that lacks nitrogen sources.
• Examples: Nepenthes sp. (pitcher plant) and Dionaea muscipula (Venus fly trap).

Effect of Habitat Change

• Compare the growth of a pitcher plant, Indian willow plant and bird’s nest fern when each is planted in soil and supplied with sufficient light, water and fertiliser.
• Record growth weekly for one month to determine which plant adapts to the habitat change.