1) Salinity stress from high salt concentrations in soil can significantly reduce crop growth and yields. It is a major problem affecting over 6% of the world's total land and 20% of irrigated agricultural areas. 2) In India, about 6.73 million hectares of land are salt-affected, with states like Gujarat, Uttar Pradesh, and Maharashtra having the highest proportions. The key causes of soil salinity are accumulation of salts in arid areas, weathering of rocks, deposition of ocean salts, and poor irrigation water management. 3) Plants have different levels of tolerance to salt stress, from highly tolerant halophytes to very sensitive non-halophytes.

1. 1
JAWAHARLAL NEHRU KRISHI VISHWAVIDALAYA
Jabalpur (M.P)
CREDIT SEMINAR 2019-2020
PRESENTED BY
MADHANA KEERTHANA S
M.Sc.(Ag.) Final year
Roll No. 180112011
DEPARTMENT OF PLANT PHYSIOLOGY
COLLEGE OF AGRICULTURE JABALPUR (M.P)
Salinity stress and its impact on plants

2. Outline
 Introduction (Salinity)
 State wise salt affected areas and distribution
 Causes of soil salinity
 Classification of plants based on salt tolerance
 Salinity stress effect on crop growth and
development
 Salinity stress tolerance
 Mechanism of salt tolerance
 Mitigation of salt stress
 Case study

5. Heavy
metals

6.  Salinity is one of the most important factors, limiting the
productivity of agricultural crops, with adverse effects on
germination, plant vigour and crop yield (R Munns &
Tester, 2008)
 It is caused due to high accumulation of SO 4
2- , NO 3- ,
CO3- of Calcium, Magnesium and Sodium.
 Excess salt in the soil, reduces the water potential of the
soil and making the soil solution unavailable to the
plants (physiological drought)
SALINITY

7. Causes of Soil Salinity
 Accumulation of salt for Arid and Semi-
arid areas
 Weathering of parental rocks
 Deposition of oceanic salts
 Agricultural land – Irrigation
 Poor water management
 High evaporation

8. What are the salt affected soils?
Salt affected
type
EC
(dsm-1)
ESP
(%)
Sodium
Absorption
Ratio
pH
Saline > 4 <15 <13 <8.0
Sodic <4 >15 >13 8.5 – 10.5
Saline - sodic > 4 > 15 Variable > 8.5
At 25 ° C

9.  It is estimated that 6 % of world’s total land and 20 % of
the world’s irrigated areas are affected by salinity. There
is a deterioration of about 1 % of world agricultural lands
because of salinity each year. (Turan et al. 2012)
 In India the area under salt affected soils is about 6.73
million ha with states of Gujarat (2.23 m ha), Uttar
Pradesh (1.73 m ha), Maharashtra (0.61 m ha), West
Bengal (0.44 m ha ) and Rajasthan (0.38 m ha) together
accounting for almost 75% of saline and sodic soils in
the country (CSSRI, 2015)
Vickers et al. (2009)
Extent of Salt affected soils

10. NBSS & LUP, Nagpur, 2010
Salt affected soils in India

11. Extent of salt affected soils in India
CSSRI, Karnal, 2010
(ha) (ha) (ha)

12. Md. Sanower hossain, 2019
Salt affeted soils – Global scenario

13. Classification of plants based on salt tolerance
Highly Tolerant
(10 ds/m)
Moderately Tolerant
(6 ds/m)
Sensitive
Barley
Sorghum
Sugarbeet
Cotton
Mustard
Rice
Sugarcane
Groundnut
Maize
Soybean
Oat
Linseed
Sesamum
Cowpea
Pea
Mungbean
Pigeonpea

14. Classification of plants based on their response to
high concentration of salts:
1. Halophytes – Native to saline soils and complete their life
cycles in that environment.
a) Group IA (Halophytes):
 Shows growth stimulation with Cl- levels below 400 mM
 Eg: Sea blite ( Suaeda maritima) and salt bush (Atriplex
nummularia).
b) Group IB ( halophytes):
 Tolerate salt, but growth is retarded.
 Eg: Townsend’s cordgrass (Spartia x townsendii) &
sugarbeet ( Beta vulgaris)

15. c) Group II (halophytes and non halophytes) :
 Includes salt tolerant halophytic grasses that lack
salt glands.
 Eg: Red fescue ( littoralis), Puccinellia peisonis
and non halophytes – Cotton, Barley
 All are inhibited by high salt concentrations.
d) Group III (Very salt-sensitive non halophytes)
 Severely inhibited or killed by low salt
concetrations.
 Eg: Fruit tress – Citrus, Avocado, Stone fruit.
2) Glycophytes ( sweet plants/non halophytes):
 Not able to resist salts to the same degree as
halophytes.

16. Effect of salt stress - General response

17. Effect of salt stress – Cellular response

18. Effect of salt stress – Whole plant response
 Leaf growth more sensitive than root growth
 Leaf expansion is limited
 Shoot growth is restricted
 New leaves emerge slowly
 Lateral buds development is reduced

19. Conti….
 In Cereals, total Leaf area is reduced
 Reduction in no. of tillers
 In dicots, size of the leaves & no. of branches reduces
 Root growth is not affected
 Slower ionic phase – accelerates senescence of mature
leaves

20. Effect of salt stress – Physiological response
 Growth is limited – osmotic effect of salt in soil &
toxic effect of salt within the plant
 Reduction in shoot growth – rapid response to the
increase in external osmotic pressure & slower
response due to accumulation of Na + in leaves
 Na + can displace Ca2+ from the plasma membrane
that can be detected as leakage of K + from the
cells.

21. Conti…
 Na + inhibit acquisition of essential element K +
 Photosynthesis, carbon metabolism and
photophosporylation may be affected.
 ROS production and cell death occurs due to
disruption of cell membrane.
 Higher chloroplast density per unit leaf area due to
smaller, thicker leaves.

22. Symptoms of Plants to Salt Tolerance
 Retardation of Growth
 Necrosis
 Leaf Abscission
 Loss of turgor
 Cessation of Growth
 Ultimate death of plant

27. Strategies for Salt tolerance
THREE STRATEGIES
1) Tolerance to osmotic stress
2) Na+ exclusion from leaf blade
 Casparian strip
 Na + enters root passively, so root cells use energy to
extrude Na + actively back to the apoplast
 Reduced long distance transport of Na + (SOS 1, SOS 2,
HKT 1)
 Increased sequestration of Na + into root vacuoles

28. Regulation of ion homeostasis by the SOS signal transduction
pathway
Taiz & Zeiger,2002
SOS1 – Plasma membrane Na+ , H+ antiporter
SOS2 – Serine/ threonine kinase
SOS3 – Ca2+ binding protein
HKT1 – Sodium influx transporter
AKT1 – Invardly rectifying K+ channel
NSCC – Non selective cation channel
NHX1, 2 & 5 – endomembrane Na + / H+ antiporter

29. 3) Tissue tolerance
 Na + sequestration
 Compatible solute synthesis
 Salt induces increase in cell size due to increase in vacuoles
volume
 Excretion of Na + and Cl - by salt glands(modified trichomes) or
bladders(modified epidermal cells)
 Intracellular comparmentation of Na +
 Increased accumulation of compatible solutes
 Increased activity of anti oxidative enzymes.

30. Mitigation of Salt stress
 Foliar spray of 0.5 ppm brassinolide for increasing
photosynthetic activity.
 Foliar spray of 2 % DAP +1 % KCl (MOP) during
critical stages
 Spray 40 ppm of NAA for arresting pre-mature fall
of flowers/buds/fruits.
 Extra dose of nitrogen (25%) in excess of the
recommendedd
 Split application of N and K fertilizers
 Seed treatment + soil application +foliar spary of
Pink Pigmented Facultative Methnatrops (PPFM)
@ 10 6 as a source of cytokinin

31. Case study

34. THANK YOU