How do pneumatophores help Sonneratia and Laguncularia mangroves survive in tidal mudflats?

Pneumatophores, often referred to as "breathing roots," are specialized lateral roots that allow Sonneratia and Laguncularia mangroves to survive in the oxygen-poor, waterlogged soils of tidal mudflats.12

These structures grow upward from the primary root system, exhibiting negative geotropism, until they project several centimeters above the low-tide level. Their survival function is facilitated by the following mechanisms:12

• Gas Exchange: The surface of these roots contains small openings called [lenticels]. These pores allow air to enter the root system, providing the necessary oxygen for root respiration in environments where the surrounding mud or water is otherwise oxygen-deficient.12
• Internal Transport: Once air enters through the lenticels, it passes through spongy tissue within the pneumatophores to reach the submerged portions of the plant's root system, ensuring the entire plant can maintain metabolic activity despite the challenging, often saline, coastal conditions.12

By enabling this essential gas exchange, pneumatophores allow these mangroves to thrive in environments that would be inhospitable to most other plants.13