Agriculture Reference
In-Depth Information
Fig. 2.4
Root systems in mangroves.
a
Stilt root of
Rhizophora
sp.,
b
Prop root of
Rhizophora
sp.,
c
Stilt root of
Rhizophora
hybrid,
d
Planks root of
Xylocarpus
,
e
Knee roots of
Bruguiera
sp.,
f
Above ground root of
Lumnitzera
sp.,
g
Above ground root of
Xylocarpus moluccensis
,
h
Pneu-
matophores of
Sonneratia
,
i
Pneumatophores of
Avicennia
Macnae (
1968
) has described adaptations of mangroves considering their growth in
ill-consolidated mud, specialization of stems and leaves, relationship between root
and shoot systems and vivipary.
2.1 Morphological Adaptations
These include various types of aerial roots for proper exchange of gases and support
of plant body, leathery shiny glaucous leaves with water storage tissue and vivipa-
rous germination in many species.
Mangroves have shallow root systems but they have adapted in a remarkable
way to withstand the conditions of the nutrition, absorption of water and oxygen
in anaerobic muddy soil and for anchorage on an unstable substratum. A variety
of root systems exists in mangroves such as aerial roots, knee roots, stilt roots,
tangle roots and pneumatophores or respiratory roots (Fig.
2.4
). The aerial roots are
highly developed and very extensive, forming intricate tangle making the move-
ment in it very difficult. They help in allowing the atmospheric gases to reach the
underground roots which lie in anaerobic soils. The strut and stilt roots in
Rhi-
