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What Is the Function of Fronds?

Fronds are leaf-like structures, comprising multiple smaller leaflets. Ferns, lichens, algae and seaweeds have fronds. Fronds perform leaf function -- converting sunlight to carbohydrates through photosynthesis -- plus additional functions including reproduction and nutrient absorption.

Types
- Fronds -- also called blades or thalli -- may be sterile or fertile. Fertile fronds contain reproductive organs because fronded plants lack the flowers that usually perform reproductive functions.
Reproduction
- Reproductive spores are clearly visible on these fern fronds.
  
  Most fern fronds have spore producing organs on the underside. Darkening with maturity, these burst open, flinging eggs and sperm outward. Others reproduce asexually, growing plantlets called bulbils. Reproduction in seaweeds and lichens may be sexual -- fronds release spores -- or asexua l-- pieces of frond break off and grow.
Nutrition
- Having fronds increases the surface area available for photosynthesis. Combatting low underwater light levels, seaweed fronds contain red and brown pigments additional to chlorophyll, harnessing a wider spectrum of light. Lacking roots and an internal nutrient transportation system, seaweeds and lichens rely on fronds to absorb nutrients from the sea or rain. Long fronds expose a greater surface area to water in the environment.
Flexibility and Flotation
- Flexible seaweed fronds resist damage; bladders add buoyancy.
  
  Relying on waves and currents to bring nutrition, seaweed's long flexible fronds resist damage in this environment. They also serve as buoyancy aids: air bladders within fronds pull them up closer to the light, enhancing photosynthesis.

Nature