Morphological and anatomical changes occur in plants under water stress. These include reduced cell and leaf expansion, increased stem thickness and wax deposition on leaf surfaces. Water stress also leads to reduced growth, yield and root expansion. Anatomical changes include the formation of aerenchyma tissue in roots and shoots to facilitate gas diffusion and transport of oxygen. Molecular mechanisms involve certain transcription factors and genes that help confer water stress tolerance.

1. Morphological,
anatomical changes
during water stress
Babanjeet
L-2021-H-85-

2. 01
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What is Water Stress ?
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No rainfall
Low temp.
High salt conc.
Transient loss of
turgor at mid
day
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 A major abiotic stress
 Induced by many environmental conditions.

3. Morphological Changes

4. 1. Growth Changes
 Reduction in cell and leaf expansion
Effect of water stress on leaf expansion of tomato

5. On leaf surface is increased, which
reduces cuticular transpiration &
increases reflection
Is increased. This in turn
compresses plasma membrane &
increase thickness
Cell thickness
Is increased as with reduced leaf
expansion, more C translocated
towards roots. This increases
water supply.
Stem length
Reduced ( potato, okra) etc .
Root growth
Wax deposition

6. Water stress causes reduction in yield. Because
2) Yield
 Water stress → reduced leaf area → reduced
photosynthetic surface → reduced light interception →
reduced dry matter production.
 Water stress → stomata closes → reduce intake of CO2 →
reduced photosynthesis → reduced dry matter production

7. Leaf movement
Leaf movement can provide additional protection against
heating during water stress.
Additional strategies for adapting leaf area to water stress:
 Loss of leaves
 Wilting (changes angle of the leaf)
 Morphology (vertical leaves)
 Leaf rolling (in grasses)
Reduction of radiation load results in less evaporation.
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8. Your Date Here Your Footer Here 8
Strong effect of water stress on leaf position in cowpea

10. Usually form in the roots
Reduce oxygen leakage
during its transport from
shoot-to-root tip
Impede soil
phytotoxin
Triggered by the
organic acids
Filled with gas spaces to
facilitate the diffusion of
oxygen
Formed in the mid-cortex
cells and its formation was
mediated by ROS
It forms in roots and
shoots
Consists of thin-walled cells
Gonzali et al 2017; Kieliszek
Anatomical Changes

11. Water stress
Molecular
mechanisms
of
ROLLB
aerenchyma
Maohuaet al 2022

12. 1
2
Phylogenetic
tree
of
TF
from
different
plant
species
These genes are
for water stress
tolerance
Tree was constructed
using a neighbor-
joining method with
1000 bootstraps
Weitao Jia et al 2021

13. Stomata closure
(D’ Amato et al 2020)