ecological adaptations of plants

1. ADAPTATIONS OF
EPIPHYTES AND
HALOPHYTES
BY
JAYALAKSHMI P S
6302

2. PLANT ADAPTATIONS
 Plants can survive in many extreme environments.
 In order to survive in such environments, these plants
need to have adaptations.
 Here ,it deals with epiphytic and halophytic
adaptations.

3. EPIPHYTES
These are mainly small shrubs or herbs
attaching themselves to trunks and
Branches, without putting down roots
in soil.
In this way, they can grow high up in
the canopy layer and capture sunlight
to carry out photosynthesis.
They are harmless to the host.
Epiphytes have aerial roots to capture
moisture from the air.

4. MORPHOLOGICAL ADAPTATION
 Roots are well developed.
 Three types of roots present.
 1.absorbing roots (absorbs minerals and nutrients from host)
 2.clinging roots(firmly fix to host)
 3.aerial roots.(spongy in nature & absorbs atmospheric moisture)
 Stems in some epiphytes are succulent and leaves are reduced in
number.

5. ANATOMICAL ADAPTATIONS
 Thick cuticle
 Sunken stomata
 Surface of aerial roots are not cutinized.
 Water storage tissues seen in succulent types.
 Aerial roots posses greenish, white thin walled massive
tissues called VELAMEN.
 Cells of velamen are hygroscopic and absorbs moisture from
air.
 Their cell wall posses spiral or reticulate thickening & does
not posses protoplasm.
 Distinct exodermis present below velamen
 Vascular system well developed.
 Cortex is parenchymatous


6. epidermis
velamen
exodermis
Air chamber
cortex
Vascular
bundle
Pith
T.S of VELAMEN ROOT

7. HALOPHYTES
 80% of the earth is covered by saline water
 Very few plants are able to tolerate saline conditions without
serious damage
 Plants that survive in saline environments are termed halophytes
 Most halophytes prefer saline conditions but can survive in
freshwater environments
 Most halophytes are restricted to saline environments.
 EG. Rizophora, Avicennia, Sonneratia.
 They posses STILT ROOTS and BUTTRESS ROOTS.
 They produce negatively geotropic breathing roots-
PNEMATOPHORES.
 Seeds germinate before their dispersal and germinated seeds fall as
seedlings and grow on suitable substratum.
 Secrete SALTS & posses water storage tissues.

8. MORPHOLOGICAL ADAPTATION
 STILT ROOTS are also called as prop roots
 Arise from aerial branches which enter the layers of soil.
 Helps efficient anchorage of plants.
STILT ROOTS
ROOT BUTTRESS

9.  PNEMATOPHORES OR BREATHING ROOTS are produced
from horizontal roots.
 Negatively geotropic and posses air pores or lenticels
 Gaseous exchange takes place through these pores.
 Anatomically made of arenchyma bering air chambers.
PNEMATOPHORES

10.  Leaves are thick leathery and glassy.
 Densely covered with branched or unbranched hairs.
 Fruits and seeds well adapted for dispersal through air and
water. Light weighted and bears air chambers.
 Viviparous germination.
 Each seedling consists of club shaped hypocotyle and
downwardly projecting radicle.

11. ANATOMICAL ADAPTATION
ANATOMY OF ROOT ANATOMY OF STEM

12. LEAF ANATOMY

13. Physiological Adaptation
 High rate of transpiration
 Release dissolved salts as exudates.
 Produce additional shallow roots for
water absorption.
Osmotic conc. Of cell sap is high; helps in the absorption of
water from saline soil.