Salt stress and its regulation in plants:
Introduction
Classification of plants on the basis of concentration of salt
How does salt accumulation in soils impairs plant function and soil structure
Effect of salinity on plant physiological growth and development
Effect of salinity on osmotic potential of plant
Plant uses different strategies to avoid salt injury.
Salinity stress
Categorization of salt affected soils
CAUSES OF SALINITY IN SOIL
Salinity effects on Plants
Injuries due to salt stress
different strategies to avoid salt injury
salt tolerance
salt avoidance
salt evasion
halophytes
non halophytes
glycophytes
Breeding for salt tolerance
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
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)
Water Stress in Plant: Causes, Effects and ResponsesSukhveerSingh31
Drought, as an abiotic stress, is multidimensional in nature, and it affects plants at various levels of their organization.Drought stress effects can be managed by production of most appropriate plant genotypes, seed priming, plant growth regulators, use of osmoprotectants, silicon and some other strategies.
Drought stress effects can be managed by production of most appropriate plant genotypes, seed priming, plant growth regulators, use of osmoprotectants, silicon and some other strategies.
Salinity stress- imbalance in soil minerals in plants, types of stress, biotic and abiotic stress, physiological effects, hyperionic stress, ion homeostasis.. Biological definition for stress is an adverse force or condition which inhibits the normal functioning and well being of a plant.
intro-classification-salt accumulation in soil imapairs plant function and soil structure-physiological effects on crop growth and development-osmotic effect and specific ion effects-plant use different strategies to avoid salt injury
Salinity stress
Categorization of salt affected soils
CAUSES OF SALINITY IN SOIL
Salinity effects on Plants
Injuries due to salt stress
different strategies to avoid salt injury
salt tolerance
salt avoidance
salt evasion
halophytes
non halophytes
glycophytes
Breeding for salt tolerance
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
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)
Water Stress in Plant: Causes, Effects and ResponsesSukhveerSingh31
Drought, as an abiotic stress, is multidimensional in nature, and it affects plants at various levels of their organization.Drought stress effects can be managed by production of most appropriate plant genotypes, seed priming, plant growth regulators, use of osmoprotectants, silicon and some other strategies.
Drought stress effects can be managed by production of most appropriate plant genotypes, seed priming, plant growth regulators, use of osmoprotectants, silicon and some other strategies.
Salinity stress- imbalance in soil minerals in plants, types of stress, biotic and abiotic stress, physiological effects, hyperionic stress, ion homeostasis.. Biological definition for stress is an adverse force or condition which inhibits the normal functioning and well being of a plant.
intro-classification-salt accumulation in soil imapairs plant function and soil structure-physiological effects on crop growth and development-osmotic effect and specific ion effects-plant use different strategies to avoid salt injury
Heavy metal stress
EFFECTS OF HEAVY METAL ON PLANTS
Sources of metal toxicity
Chromium, manganese, zinc, aluminum, copper, nickel
ALLUMINIUM TOXICITY IN SOIL
Inhibition of Ca Uptake by AIuminium
Aluminium tolerance in soil by internal accumulation
Aluminium tolerance in soil by exclusion
CADMIUM TOXICITY IN SOIL
CADMIUM ACCUMULATION IN PLANTS
CADMIUM TOXICITY IN PLANTS
CADMIUM TOLERANCE MECHANISM
ROLE OF PHYTOCHELATINS
Water stress in plants: A detailed discussionMohammad Danish
A brief introduction of drought stress in plants, its effect on morphological, physiological and biochemical properties of plants and management strategies to mitigate drought stress.
Plants can't move and get out of the way when water levels become difficult to handle. Flooding and soil saturation leads to a depletion of oxygen in the soil and reduction of light and carbon dioxide availability. So how do plants deal with the stress of being flooded?
Heavy metal stress
EFFECTS OF HEAVY METAL ON PLANTS
Sources of metal toxicity
Chromium, manganese, zinc, aluminum, copper, nickel
ALLUMINIUM TOXICITY IN SOIL
Inhibition of Ca Uptake by AIuminium
Aluminium tolerance in soil by internal accumulation
Aluminium tolerance in soil by exclusion
CADMIUM TOXICITY IN SOIL
CADMIUM ACCUMULATION IN PLANTS
CADMIUM TOXICITY IN PLANTS
CADMIUM TOLERANCE MECHANISM
ROLE OF PHYTOCHELATINS
Water stress in plants: A detailed discussionMohammad Danish
A brief introduction of drought stress in plants, its effect on morphological, physiological and biochemical properties of plants and management strategies to mitigate drought stress.
Plants can't move and get out of the way when water levels become difficult to handle. Flooding and soil saturation leads to a depletion of oxygen in the soil and reduction of light and carbon dioxide availability. So how do plants deal with the stress of being flooded?
Physiological response of plants against stress for pg and ug botany..which include types of stresses their effects, salt tolerance etc...by Megha Yasodharan Pg student SN college chempazhanthy
Salt tolerance in Halophytes & Glycophytesrakz2017
GLYCOPHYTES – Salt sensitive plants
HALOPHYTES can survive and complete their life cycle in salt concentrations of 200 mM NaCl .
Halophytes can be further categorized as euhalophytes (true halophytes), pseudohalophytes (salt avoiders) and crinohalophytes (salt excreters). One of the striking features of most of these halophytes is the correlation between uptake of cations and whole plant succulence.
In this presentation, I would like to provide the Resistance Mechanism and Molecular Responses to the Salinity.
There are two types of plants Halophytes and Glycophytes (categories on the basis of their responses to the salinity) examples are Thellungiella halophila and Arabidopsis thaliana, respectively.
Earlier Arabidopsis was considered as Model organism incase of plants but it can't tolerate high saline condition that's the reason for the limited study of plant towards salinity responses. But in the year 2004 the discovery of new plant Thellungiella halophila generates new knowledge about the tolerance mechanism of plants towards salinity responses because it's a halophytes which can tolerate extreme saline condition.
And also it has very similarity with the Arabidopsis so it's considered as the Model organism for the study of Salt stress physiology.
There are major two pathways involved in response to Salt stress (described in presentation).
Constrains in Crop Production in saline soil & its Management.pptxSarthakMoharana
Some of the constrains in crop production in Saline soil & its Management. Salinization cause major factor which decline the soil fertility and leads to reduction of productivity of cultivable lands.
But there measures which can be taken to prevent it or rather reduce it to minimum.
Scientist are working on various techniques to prevent the Salinization problem in soil such as production of salt resistant crops, etc.
Leaching is one of the easiest method to counter this issue.
Introduction to salt-affected soils. Types of salt-affected soils and their effect on crop growth. Methods to reclaim and manage salt-affected soils for better agriculture production.
Alkaline Soils
Clay soils with a pH of more than 8.5 are classified as alkaline soils. The higher pH is caused by high quantities of salt, magnesium, and calcium. Furthermore, hard water can cause the pH of soils to rise to alkaline proportions. On the other hand, sodium carbonate is the dominant component in alkaline soil. Therefore, alkaline soils inflate when exposed to sodium carbonate.
Saline Soils
When there is an overabundance of sodium ions in the clay and soil complex that still includes exchangeable calcium, the soil is referred to as saline soil, brown alkali soil, or white alkali soil. This soil continues to be flocculated or granulated. As a result, it has air and water permeability.
Agriculture on Saline and Alkaline Soils
Coconut trees may be found in abundance in coastal settings. In addition, as previously stated, farming salt-tolerant crops such as dhaincha, berseem, and other grain legume crops may aid in the reclamation of these soils. Moreover, some of the suitable agriculture on saline-alkaline soil is mentioned below:
Suitable Crops: Barley, Cotton, Sugar beet, Sugarcane, Rice, Mustard, Maize, Green Gram, Red Gram, Sunflower, Sesame, Linseed, Sorghum, Bajra, etc.
Suitable Vegetables: Tomato, Cauliflower, Cabbage, Cucumber, Bitter guard, Pumpkin, Spinach, etc.
Suitable Fruits: Guava, Beetroot, Asparagus, Coconut, Banana, Grape, Pomegranate, Date palm, etc.
Features of Saline and Alkaline Soils
The topsoil of Saline and Alkaline Soil is permeated (saturated or soaked with a material) with alkaline and saline efflorescences.
Weathering produces calcium salts, magnesium, sodium, and sulfurous acid from inert rock pieces.
In areas with a lower water table, salts permeate the subsurface, but in areas with high drainage, salts are washed away by running water.
Certain salts are delivered in suspension by rivers.
In places with a higher subsoil surface water, harmful salts are carried below by capillary forces during the summer months due to evaporation.
Water with a high salt content becomes stationary in places with inadequate drainage and accumulates all of the salt contents in the soil layer as it dissipates.
Alkaline and Saline Soil Areas in India
Saline and Alkaline Soil covers an area of 68,000 square kilometers. These soils are formed in canal rinsed lands and locations with a higher subsurface water table. This type of soil may be found in parts of Karnataka, Telangana, Andhra Pradesh, Uttar Pradesh, Bihar, Punjab, Haryana, Rajasthan, Punjab, and Maharashtra. However, the build-up of the salts leaves the soil unproductive and unsuited for cultivation.
The sea tides transporting salt-laden sediments damage the lands near the Khambhat Gulf of Gujarat. As a result, vast portions of the Mahi, Tapi, Narmada, and Sabarmati rivers are unproductive. When severe storms, salty sea waves invade coastal locations, rendering the soil unsuitable for farming.
Current trends and future prospects of halophilic microbes in agricultureNagaraju Yalavarthi
halophiles are the microorganisms that capable of living under salt conditions, generally many microbes are susceptible to higher salt concentration whereas these microbes tolerate higher salinity
Heavy Metal Stress and its coping mecganism..pptxInam UL Haq Syed
Heavy metal stress causes a reduction in molecular oxygen and releases highly reactive intermediate products such as hydrogen peroxide (H2O2), superoxide radicals and hydroxyl radicals known as reactive oxygen species.
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2. CONTENT:
Introduction
Classification of plants
Salt Accumulation in soils impairs plant function and soil
structure
Physiological effect on plant growth and development
Osmotic effect and specific ion effects
Plant uses different strategies to avoid salt injury.
3. Salt stress:
Salt stress is the accumulation of excessive salt contents in the soil
which eventually results in the inhibition of crop growth and leads to
crop death.
4. classification of plants:
Based on the responses high concentration of
salt ,plants can be divided into two broad
groups:
Halophytes are native to saline soils and complete their life
cycles in that environment.
Glycophytes (literally “sweet plants”) or Non Halophytes are
not able to resist salts to the same degree as Halophytes.
Halophytes
Glycophytes
5. Classification of plants based on salt tolerance:
• Sugar beet, Barley, cotton, date palm……..
Highly tolerant crops:
• Rye, Sorghum, Wheat, Soybean……..
Moderately tolerant :
• Rice, tomato, potato, radish…….
Moderately sensitive:
• Citrus, strawberry, peas, carrot……
Extremely sensitive:
6. Salt accumulation in soils impairs plant function and soil structure:
The effect of salts in the soil we distinguish
between high concentration of Na+ referred to as
Sodicity , and high concentration of total salts
referred to as Salinity.
The high Sodium ion concentration of a Sodic soil
can not only injure plants directly but also degrade
the soil structure, decreasing porosity and water
permeability.
In the field, the salinity of soil water or irrigation
water is measured in terms of Osmotic potential.
7. The conductivity of water sample is due to the ions dissolved in it.
In the united states the salt content of the headwaters of the Colorado river is
only 50 mg/lit, about 2000km down down streem, in Southern California, the
salt content of the Sam river reaches about 900mg/lit,enough to preclude
growth of some salt-sensitive crops,such as Maize.
Salinity decreased throughout upper Colorado
8.
9. Physiological effects on crop growth and development:
on growth:
Decreased rate of leaf growth after
an increase in soil salinity is primarily
due to the osmotic effect of salt
ground the roots.
Increase in soil salinity causes leaf
cell to loose water.
Reduction in cell elongation and also
cell division lead to slower leaf
appearance and smaller final size.
10. germination
Seed germination in saline condition is affected by
three ways:
Increased osmotic pressure of the soil solution
which restrict the absorption and entry of water into
the seeds.
Certain salts constituents are toxic to the embryo
and seedlings . Anions like carbonate ,nitrate
,chloride ,sulphide ions are more harmful to seed
germination.
Salt stress hampers the metabolism of stored
materials.
11. photosynthesis:
Accumulation of high concentration of sodium
and chloride ions in chloroplast ,
photosynthesis is inhibited.
Since photosynthetic electron transport
appears relatively insensitive to salts, either
carbon metabolism or photophosphorylation
may be affected .
Photosynthetic enzyme or the enzymes
responsible for carbon assimilation are very
sensitive to the presence of Nacl.
12. Nitrogen metabolism:
The key enzyme ,nitrate reductase is very
sensitive to Nacl.
One of the amino acid glycinebetaine shows
increased trend with increase trend with increase
in salinity in perennial halophytes and Atriplex
Sps.
Proline is an alpha amino acid ,accumulates in
large amounts as compared to all other amino
acids in salt stressed plants.
13. Osmotic effect and specific ion effects:
Dissolved solutes in the rooting zone generate a
low osmotic potential that lowers the soil water
potential .
The general water balance of plants is thus
affected because leaves need to develop an even
lower water potential to maintain a “downhill ”
gradient of water potential between the soil and
leaves.
During soil desiccation a finite amount of water
can be obtained from the soil profile by the plants
, causing over decreasing water potentials.
14.
15. In addition to the plant responses to low water potential , specific ion toxicity
effects also occur when injurious concentrations of ions –particularly Sodium
,chloride or Sulphide ions accumulate in cells.
An abnormally high ratio of Sodium to potassium ions and high concentration
of total salts inactivate enzymes and inhibit protein synthesis.
At high concentration Sodium can displace Calcium from the plasma
membrane of cotton root hairs , resulting in a change in plasma membrane
permeability that can be detected as leakage of potassium from the cell.
16. Plants use different strategies to avoid salt injury:
Plant minimize salt injury by excluding salt from
meristems , particularly in the shoot , and from
leaves that are actively expanding and
photosynthesizing .
The casparian strips imposes a restriction to the
movements of ions into xylem.
Sodium ion enters roots passively , so root cells
must use energy to extrude sodium ion actively
back to the outside solution .
By contrast , chloride is excluded by negative
electric potential across the cell membrane , and
the low permeability of root plasma membranes to
this ions.
17.
18. Although some plants ,such as mangroves ,grow
in saline environments with abundant water
supplies ,the ability to acquire that water requires
that they make osmotic adjustments to obtain
water from the low-water –potential external
environments.
Many halophytes exhibit a growth optimum at
moderate levels of salinity , and this optimum is
correlated with the capacity to accumulate ions in
the vacuole , where they can contribute to the cell
osmotic potential without damaging the salt-
sensitive enzymes.
19. Sodiumis transported across the plasma membrane and the
tonoplast:
Hydrogen pumps in the plasma membrane and tonoplast provide the driving
force for secondary tonoplast of ions.
Activity of these pumps is required for the secondary transport of excess ions
associated with plant responses to salinity stress.
This is indicated by findings showing that the activity of these hydrogen pumps
is increased by salinity, and induced gene expression may account for some of
this up –regulation.
20.
21. Energy dependent transport of Sodium ion from the cytosol of plants cells
across the plasma membrane is mediated by the gene product of the
SOS1(Salt Overlay Sensitive 1) gene that function as Sodium-hydrogen
antiporter .
The SOS1 antiporter is regulated by the gene products of at least two other
genes , referred to as SOS2 and SOS3.
SOS2 is a serine/threonine kinase that is apparently activated by calcium
through the function of SOS3a Calcium –regulated protein phosphatase.
22. Conclusion:
Salt stress is one of the global issue causing many socio-economic
problems.
Every year agriculture sector looses its 806.4 billion rupees.
The present trend of degradation continued ,the projections are that
India will have 11.7 M hectare area is affected by soil salinity and
alkalinity (2025) .
About 25 percent of the ground water resources are saline and sodic
and as such are not suitable for irrigation of field crops.