Mangrove trees are subjected to exceptionally high and variable demands for water transport, both in time and space. The combination of saline water, periods of flooding alternating with drought periods, and high temperature suggests an adaptive hydrosystem to control the impact of drought-induced cavitation. However, little is known about the ecological plasticity of the hydraulic architecture of mangrove trees and its functional significance to guarantee sap flow under all environmental conditions. The variability of vessel structure and intervessel pit anatomy was studied both along a salinity gradient and between seasons in two species with different ecological distributions in the mangrove forest of Gazi Bay (Kenya), Rhizophora mucronata and Avicennia marina. In addition, secondary wood formation via successive cambia of the highly drought stress-resistant A. marina was investigated for its relationship with soil water salinity. The ecological plasticity in vessel density and pit membrane thickness could be related to a safe hydrosystem by increased redundancy in the conduit network and resistance of the pit membrane against air-seeding, respectively, with increasing substrate salinity. Vessel diameter and intervessel pit size, in contrast, seem to adopt a constant optimal value. An additional role could be assigned to the patchy growth mechanism of A. marina.
|Name||African Botany in Brussels|
|Conference||Finds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet|
|Period||21/09/09 → 25/09/09|
- Hydraulic architecture
- water transport