Abiotic stress: how the effect on plant and what it's mechanism

2. Abdul Awal Chowdhury Masud
Reg No. 10-03844
Department of Agronomy
Sher-e-Bangla Agricultural University

3. STUDY THE MECHANISM OF
DROUGHT TOLERANCE IN
PLANT

4. Presentation Outline
 Background Information
 Abiotic stress & Drought
 Drought effect on crop
 Stress tolerance mechanism
 Conclusion & Recommendations
 Q & A
4

5. Objectives
 Get an overview on abiotic stress induced drought stress
 Study plant responses to drought stress
 Discuss Drought effect on crop growth and yield
 Outline drought tolerance mechanism in plant
To…
5

6. Background

7. 7.5 Bln
current population
7

8. 8

9. Stress?
Unfavourable
conditions that affects
or blocks a plant’s
metabolism, growth or
development
(gaspar et al., 2002)
Adverse situation that
create mental or
emotional strain
9

10. Plant
10

11. Nutrient
Imbalance
Water
stress
Mechanical
stress
Temp.
stress
Pollutants
Radiation
(Light,UV)Heavy
Metal
Salinity
Figure. Plant faces Abiotic Stresses
Drought
Abiotic
Stress
11

12. Introduction

13. Drought
Unavailability of water as required by plants due to physical
or physiological reason
Physical: insufficient rainfall, high temperature
Physiological: salinity, ion imbalance, osmotic regulation
13

14. Drought: World Scenario
 Affects 35% of the world’s agricultural land
 Drought prone Approx. 26% of world arable land
 Limits >50% of world agricultural productivity
(Comas et al. 2013)
 Due to drought and desertification each year 12 million
hectares are lost, where 20 million tons of grain could
have been grown (FAO, 2014)
14

15. Fig: world trends in Drought (20-21th C)
(Sheffield et al, 2011) 15

16. Drought Types
Meteorological Drought
 Rainfall < 25 % of the average of the region.
 (<50 %- severe drought)
16

17. Drought Types
Agricultural Drought
 lack of rainfall result in insufficient moisture in the root zone
17

18. Drought Types
Hydrological Drought
• Extended dry period
• Marked depletion of surface water
• Drying up of reservoir, lacks ,streams, rivers etc.
18

19. Materials & Methods

20. Materials & Methods
Materials
 Different crop species
Methods
 Stress defense mechanism by plant
 Drought stress mechanism in plant
 Drought effect on plant
 Tolerance mechanism
* Information collected from secondary sources ( Journals, Books,
thesis, online, etc.) 20

21. ROS
Reactive oxygen species
(1O2, O2
-,OH-,H2O2)
AOX
Enzymatic
(SOD, CAT,
GPX, GR)
Non-Enzymatic
(AsA, GSH, GS
SG, DHA)
Balance
Normal Plant
Plant stress defense mechanism
21

22. What happens, while
Plant got stressed ??
What is oxidative
stress??
22

23. Imbalance
Stressed Plant
23

24. Protein
degradation
ROS effects
on plant
Enzyme
inactivation
DNA damage
Lipid
peroxidation
24

25. Drought stress Mechanism
Drought stress
(reduced water
availability)
ABA signaling
Stomatal closure
Diminished CO2 influxROS Production
Oxidative
Stress
Fig: Drought stress mechanism in plant 25

26. Effect of Drought on plant
1. Reduced seed germination & seedling development
2. Poor vegetative growth
3. Effect on Photosynthesis
4. Affect reproductive growth
5. Reduced plant height and leaf area
6. Severely reduce leaf weight
7. Reduce stomatal conductance
26

27. Drought effect on plant growth
Drought stress
(Reduced water
availability)
Impaired
mitosis
Limited cell
division
Obstructed cell
elongation
Loss of turgor
Diminished
growth
Fig. Mechanisms of growth reduction under drought stress
(Farooq et al., 2009)
27

28. Drought Effect on crop yield
Crop Growth stage Yield reduction
Barley Seed filling 49–57%
Maize Grain filling 79-81%
Maize Vegetative 25–60%
Maize Reproductive 63–87%
Rice Reproductive 24–84%
Chickpea Reproductive 45–69%
Pigeon pea Reproductive 40–55%
Soybean Reproductive 46–71%
Cowpea Reproductive 60–11%
Table. 1 Economic yield reduction by drought stress in
some representative field crops. (Farooq et al., 2009) 28

29. Drought Tolerance Mechanism
Includes..
Morphological, physiological and biochemical
modification in plant to cope with drought
 Escape
 Avoidance
 Tolerance
29

30. Drought Tolerance Mechanism
Drought Escape
 Complete crop life-cycle before soil water depletion
 Form dormant seed before dry season commence
30

31. Drought Tolerance Mechanism
Drought avoidance
 Maintain relative water balance despite low soil water
 Deeper root growth in the soil
 Stomatal control of transpiration
 Reduced surface by smaller and thicker leaves
Figure: Drought Avoidance : Reduced surface by
smaller and thicker leaves
31

32. Drought Tolerance Mechanism
Drought tolerance
 withstand water deficit with low tissue water potential
 osmotic adjustment (a process which induces solute
accumulation in cell)
32

33. Plant stress tolerance protectants
Osmoregulators
 Proline
 Sucrose
 Trehalose
 Glycine betaine
 Alaninebetaine
 Prolinebetaine
Phyto-hormones
 Auxin
 Cytokinins
 Abscisic acid
 Ethylene
 Gibberellins
 Salicylic acid
 Brassinosteroids
 Jasmonates
Signaling molecules
 H2O2
 Nitric oxides
Antioxidants
 Ascorbic acid
 Glutathione
 α-Tocopherol
Trace elements
 Micro-nutrients
 K, Ca, Mg, S,
Zn,Mo, Cu, etc.
Polyamines
 Arginine
 Ornithine
 Spermidine
33

34. Conclusion & Recommendation

35. Conclusion
 Global warming increasing drought effect on crop
productivity
 To feed the increasing population stresses need to
manage to ensure food security
 Integration of the molecular approaches, morpho-
physiological analysis, and conventional breeding
strategies will accelerate cultivating drought-resistant
plants for agricultural production. 35

36. Recommendation
 The crop plant have involved certain resistance
against drought stress
 We should identify these mechanism and traits
 Need to develop more drought tolerant
varieties
36

37. Recommendation
 Non conventional approaches i.e. molecular
breeding can play a significant role to built
drought tolerance.
 Genomic regions carrying drought tolerant
gene can contribute for abiotic stress
tolerance.
37

38. Feed me to feed you…….
17th June
World day to combat desertification