Knee roots are a type of specialized root structure found in certain plants, particularly those growing in oxygen-poor environments like mangrove swamps.
Understanding Knee Roots
Based on the provided reference, knee roots emerge as a root loop from the underground root system. This unique shape, resembling a bent knee, gives them their name.
Their primary function is crucial for the plant's survival in challenging conditions: they allow the exchange of gases in oxygen-poor sediments. This means they help the plant's root system "breathe" where oxygen levels are very low or non-existent in the mud or soil.
Characteristics and Examples
While knee roots can vary among species, the reference provides specific details about those found on an adult Bruguiera gymnorhiza tree:
- Emergence: Emerge as distinctive loops from the main underground root system.
- Function: Facilitate gas exchange (oxygen uptake, carbon dioxide release) in anoxic (oxygen-deficient) soil.
- Reach: The knee roots of an adult Bruguiera gymnorhiza extend in a radius of approximately 10 meters around the trunk.
- Height: They can reach a height of up to 60cm above the sediment surface.
This ability to access atmospheric oxygen is vital for the root cells, which require oxygen for respiration and growth, even when submerged in waterlogged, oxygen-depleted substrates.
