Drought stress and tolerance mechanisms in cropsMohaned Mohammed
Drought stress accounts for more crop production losses than any other factor. The presentation discusses the causes and effects of drought stress on plants and various tolerance mechanisms. It outlines that drought avoidance mechanisms include increased water absorption and transport, deep root systems, and reduced transpiration. Physiological responses include osmolyte accumulation, antioxidant production, and hormonal changes. Developing crops with drought tolerant traits through both conventional and molecular breeding approaches will be important for improving productivity under increasing drought conditions from climate change.
This presentation outlines the mechanisms of drought tolerance in plants. It discusses how drought stress affects crop growth and yield, and the various tolerance mechanisms plants have evolved, including escape, avoidance, and tolerance. Drought stress can cause oxidative stress in plants through increased reactive oxygen species production. Plants have developed morphological, physiological and biochemical modifications to cope with drought, such as osmotic adjustment, antioxidant production, and hormonal signaling. Integrating molecular approaches with conventional breeding is recommended to develop new crop varieties with improved drought resistance and ensure future food security.
plant drought effects, mechanisms and managementG Mahesh
This presentation provides an overview of plant drought stress, including its effects, mechanisms, and management strategies. Drought stress can impact plant growth, yield, water relations, photosynthesis, nutrient uptake, and cause oxidative damage. Plants have developed morphological, physiological and molecular mechanisms to tolerate drought, such as escaping dry conditions, reducing water loss through stomatal control, antioxidant production, and accumulating compatible solutes. The presentation also discusses strategies to manage drought, including improving crop genotypes and optimizing agronomic practices to enhance drought resistance.
Drought and heat are major abiotic stresses that negatively impact plant growth and productivity. Drought stress reduces photosynthesis and induces stomatal closure and changes in gene expression and metabolism. Plants have developed various tolerance mechanisms including escape, avoidance, and tolerance. At the molecular level, plants respond to stresses through signaling pathways, changes in hormone levels like ABA, and expression of genes that encode protective proteins and osmoprotectants. Molecular responses are regulated by transcription factors that control stress-related gene expression. Engineering stress tolerance genes into crops holds promise to improve abiotic stress resistance.
1. Plants have developed three main adaptations to salinity stress: osmotic stress tolerance, sodium exclusion from leaves, and tissue tolerance to accumulated sodium and chloride in leaves.
2. Mechanisms of salinity tolerance include compartmentalization of ions, osmotic adjustment through compatible solutes, and exclusion of sodium from leaves.
3. Breeding efforts have developed salt tolerant varieties of crops like rice, wheat, mustard, and chickpeas through marker-assisted selection and identifying favorable quantitative trait loci.
This presentation gives the insight idea about drought and its effect on the plant system also talks about development of drought-tolerant variety for ensuring food security.
This document discusses abiotic stress in plants. It defines plant stress and describes how environmental factors like water deficit, salinity, temperature extremes, and mineral deficiencies can stress plants. It explains how plants acclimate and adapt to stress through physiological and morphological changes. The document outlines various stress sensing, signaling pathways and hormonal responses in plants, as well as developmental and antioxidant mechanisms that help protect plants from abiotic stress. Developing crop varieties with enhanced stress tolerance is an important goal.
This document provides an outline and overview of heat stress on plants. It begins with an introduction that defines heat stress and its effects on plant growth and development. It then discusses the perception of high temperature in plants and their responses, including morphological, physiological and molecular adaptations. The mechanisms of heat tolerance are also examined, particularly the role of heat shock proteins in protecting plant cells from damage. The document concludes that plants can adapt to heat stress through antioxidant protection and heat shock proteins maintaining protein stability.
Drought stress and tolerance mechanisms in cropsMohaned Mohammed
Drought stress accounts for more crop production losses than any other factor. The presentation discusses the causes and effects of drought stress on plants and various tolerance mechanisms. It outlines that drought avoidance mechanisms include increased water absorption and transport, deep root systems, and reduced transpiration. Physiological responses include osmolyte accumulation, antioxidant production, and hormonal changes. Developing crops with drought tolerant traits through both conventional and molecular breeding approaches will be important for improving productivity under increasing drought conditions from climate change.
This presentation outlines the mechanisms of drought tolerance in plants. It discusses how drought stress affects crop growth and yield, and the various tolerance mechanisms plants have evolved, including escape, avoidance, and tolerance. Drought stress can cause oxidative stress in plants through increased reactive oxygen species production. Plants have developed morphological, physiological and biochemical modifications to cope with drought, such as osmotic adjustment, antioxidant production, and hormonal signaling. Integrating molecular approaches with conventional breeding is recommended to develop new crop varieties with improved drought resistance and ensure future food security.
plant drought effects, mechanisms and managementG Mahesh
This presentation provides an overview of plant drought stress, including its effects, mechanisms, and management strategies. Drought stress can impact plant growth, yield, water relations, photosynthesis, nutrient uptake, and cause oxidative damage. Plants have developed morphological, physiological and molecular mechanisms to tolerate drought, such as escaping dry conditions, reducing water loss through stomatal control, antioxidant production, and accumulating compatible solutes. The presentation also discusses strategies to manage drought, including improving crop genotypes and optimizing agronomic practices to enhance drought resistance.
Drought and heat are major abiotic stresses that negatively impact plant growth and productivity. Drought stress reduces photosynthesis and induces stomatal closure and changes in gene expression and metabolism. Plants have developed various tolerance mechanisms including escape, avoidance, and tolerance. At the molecular level, plants respond to stresses through signaling pathways, changes in hormone levels like ABA, and expression of genes that encode protective proteins and osmoprotectants. Molecular responses are regulated by transcription factors that control stress-related gene expression. Engineering stress tolerance genes into crops holds promise to improve abiotic stress resistance.
1. Plants have developed three main adaptations to salinity stress: osmotic stress tolerance, sodium exclusion from leaves, and tissue tolerance to accumulated sodium and chloride in leaves.
2. Mechanisms of salinity tolerance include compartmentalization of ions, osmotic adjustment through compatible solutes, and exclusion of sodium from leaves.
3. Breeding efforts have developed salt tolerant varieties of crops like rice, wheat, mustard, and chickpeas through marker-assisted selection and identifying favorable quantitative trait loci.
This presentation gives the insight idea about drought and its effect on the plant system also talks about development of drought-tolerant variety for ensuring food security.
This document discusses abiotic stress in plants. It defines plant stress and describes how environmental factors like water deficit, salinity, temperature extremes, and mineral deficiencies can stress plants. It explains how plants acclimate and adapt to stress through physiological and morphological changes. The document outlines various stress sensing, signaling pathways and hormonal responses in plants, as well as developmental and antioxidant mechanisms that help protect plants from abiotic stress. Developing crop varieties with enhanced stress tolerance is an important goal.
This document provides an outline and overview of heat stress on plants. It begins with an introduction that defines heat stress and its effects on plant growth and development. It then discusses the perception of high temperature in plants and their responses, including morphological, physiological and molecular adaptations. The mechanisms of heat tolerance are also examined, particularly the role of heat shock proteins in protecting plant cells from damage. The document concludes that plants can adapt to heat stress through antioxidant protection and heat shock proteins maintaining protein stability.
The document discusses abiotic stress responses in plants, with a focus on drought stress. It defines abiotic stress and describes different types of drought stress and plant responses. It discusses the genetic basis of drought tolerance and key pathways involved. The document summarizes stress tolerance mechanisms in plants, including detoxification, chaperoning, late embryogenesis abundant proteins, osmoprotection, and water and ion movement. Case studies on transgenic crops with improved drought tolerance are also mentioned.
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
Stress due to temperature physiological and biochemical responses of fruit pl...sukhjinder mann
The document discusses temperature stress in fruit plants from both high and low temperature extremes. It provides context on what stress is and defines temperature stress. It then discusses the climatic temperature requirements of various fruit crops and the physiological and biochemical responses plants have to high and low temperature stress, including effects on photosynthesis, hormones, membrane properties, antioxidant activity, and more. It also discusses mechanisms plants use to cope with temperature stress extremes, such as cold acclimation and freezing tolerance processes. Lastly, it provides some management strategies farmers can use to help mitigate temperature stress impacts.
The document discusses various topics related to physiological stress tolerance in plants. It defines different types of stresses plants face, including abiotic stresses like cold, heat, salinity, drought, excess water, and radiation. It describes plant responses to stresses like avoidance, tolerance, and acclimation. The document also discusses stress measurement techniques, effects of high temperatures on photosynthesis, cross tolerance between abiotic and biotic stresses, and manipulating freezing tolerance in plants through cold acclimation.
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
The document summarizes plant responses to different types of stress. It discusses how plants can avoid or tolerate stress through mechanisms like osmotic adjustment, accumulation of compatible solutes, and heat shock protein production. Stress can be biotic, imposed by other organisms, or abiotic arising from environmental deficits or excesses. Abiotic stresses discussed include drought, high salinity, temperature extremes, and oxidative stress from pollutants. Stress triggers changes in gene expression and metabolism that help plants withstand damaging conditions.
This document discusses various types of temperature and light stresses that can impact plants. It covers chilling injury that occurs between 0-10°C, freezing injury below 0°C, and heat stress from high temperatures. It also addresses light stress factors like light deficit, high intensity light, and ultraviolet radiation. The key effects of these stresses include membrane damage, protein degradation, inhibition of photosynthesis, and oxidative damage. Tolerant plants have mechanisms like heat shock proteins and screening compounds to better withstand these environmental stresses.
Seed dormancy allows seeds to remain dormant during unfavorable conditions until conditions become suitable for germination. There are two main types of dormancy - primary and secondary. Primary dormancy occurs due to internal factors like hormones, while secondary dormancy is caused by external factors like temperature. Dormancy can be overcome through methods like scarification, stratification, hormone treatment, and photoperiod manipulation. Seed dormancy provides important biological benefits like survival during drought or frost and dispersal to new areas.
This document discusses drought stress and the physiological traits that affect a crop's response to drought. It defines drought and categorizes it as agricultural, meteorological, or hydrological drought. It describes drought resistance mechanisms in plants like escape, avoidance, tolerance, and desiccation postponement or tolerance. It discusses various physiological traits that confer drought resistance, such as phenology, root architecture, leaf water potential, relative water content, stomatal conductance, anatomical modifications, oxidative damage response, osmotic adjustment, water use efficiency, osmolyte production, late embryogenesis abundant proteins, and more.
The document discusses various types of stress that can affect plants, including biotic stress from pathogens and abiotic stress from physical and chemical factors like drought, flooding, temperature extremes, light levels, salt levels, air pollution, wind, and nutrient deficiencies or toxicities. It describes how each stress can impact plant growth and physiology and outlines some strategies plants use to tolerate or avoid stress, such as escaping the stress period, avoiding stress through morphological adaptations, or tolerating stress through physiological and biochemical mechanisms.
- Chilling stress occurs in plants when they are exposed to temperatures above freezing, between 0-15°C. It can cause physiological disorders and injury.
- Symptoms vary between plant species but include wilting, water soaked lesions, leaf curling/crinkling, and reduced growth or death. This is due to impacts on cell membranes and metabolism.
- Plants native to warm climates are most susceptible, while those from cooler regions can acclimate to develop chilling tolerance through changes to lipid composition and protective compounds. Proper management can also help plants withstand low temperatures.
Antitranspirants and their effect on crop O.P PARIHAR
This document discusses antitranspirants and their effects on crops. It defines antitranspirants as compounds that reduce water loss through transpiration without significantly impacting plant growth or photosynthesis. There are four types of antitranspirants: stomatal closing, filmforming, reflecting, and growth retardants. The document provides examples of how antitranspirants have been shown to improve wheat, maize, barley and soybean yields under drought conditions by reducing water loss from the plants. However, it also notes that antitranspirants can potentially reduce photosynthesis and increase leaf temperatures if used.
This document discusses Zhou Yan's research interests in plant physiology, specifically stress physiology. It provides an overview of stress types in plants, including biotic, abiotic, chilling, freezing, heat, and drought stresses. It also discusses resistance mechanisms in plants, such as stress avoidance and stress tolerance. Zhou Yan's current research focuses on the effects of saline and alkaline stresses on soybean seedlings. The research examines impacts on growth factors and ionic balance, as well as the mechanisms plants use to adapt, such as osmotic regulation and ion regionalization.
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.
LEA(late embryogenesis abundant) protiens and heat shockBrahmesh Reddy B R
The document discusses abiotic stress in plants and the roles of late embryogenesis abundant (LEA) proteins and heat shock proteins. It states that LEA proteins accumulate in seeds during late development under drought stress and help protect plants from stress by stabilizing proteins and membranes. The document outlines various functions of LEA proteins, including protecting target proteins from damage, preserving membrane integrity, sequestering ions, acting as hydration buffers, and contributing to the formation of intracellular glasses that allow plant survival in dry conditions. It also notes that heat shock proteins help protect plants during stress by refolding proteins and maintaining homeostasis and membrane integrity.
Osmoregulation, and adaptation in plants against abiotic factors plant stres...Raheel Hayat Rahee
Osmoregulation allows organisms to maintain homeostasis by regulating water and electrolyte balance. It works through osmosis, where water moves across semipermeable membranes to areas of higher solute concentration. Organisms excrete excess water and solutes. Plants regulate osmoregulation through structures like stomata and use vacuoles and specialized adaptations depending on their habitat. Abiotic stress like drought, salinity, temperature extremes, and heavy metals can damage plants, but plants have developed tolerance mechanisms like avoidance, escape, and acclimation to survive environmental stresses.
The document discusses abiotic stress responses in plants, with a focus on drought stress. It defines abiotic stress and describes different types of drought stress and plant responses. It discusses the genetic basis of drought tolerance and key pathways involved. The document summarizes stress tolerance mechanisms in plants, including detoxification, chaperoning, late embryogenesis abundant proteins, osmoprotection, and water and ion movement. Case studies on transgenic crops with improved drought tolerance are also mentioned.
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
Stress due to temperature physiological and biochemical responses of fruit pl...sukhjinder mann
The document discusses temperature stress in fruit plants from both high and low temperature extremes. It provides context on what stress is and defines temperature stress. It then discusses the climatic temperature requirements of various fruit crops and the physiological and biochemical responses plants have to high and low temperature stress, including effects on photosynthesis, hormones, membrane properties, antioxidant activity, and more. It also discusses mechanisms plants use to cope with temperature stress extremes, such as cold acclimation and freezing tolerance processes. Lastly, it provides some management strategies farmers can use to help mitigate temperature stress impacts.
The document discusses various topics related to physiological stress tolerance in plants. It defines different types of stresses plants face, including abiotic stresses like cold, heat, salinity, drought, excess water, and radiation. It describes plant responses to stresses like avoidance, tolerance, and acclimation. The document also discusses stress measurement techniques, effects of high temperatures on photosynthesis, cross tolerance between abiotic and biotic stresses, and manipulating freezing tolerance in plants through cold acclimation.
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
The document summarizes plant responses to different types of stress. It discusses how plants can avoid or tolerate stress through mechanisms like osmotic adjustment, accumulation of compatible solutes, and heat shock protein production. Stress can be biotic, imposed by other organisms, or abiotic arising from environmental deficits or excesses. Abiotic stresses discussed include drought, high salinity, temperature extremes, and oxidative stress from pollutants. Stress triggers changes in gene expression and metabolism that help plants withstand damaging conditions.
This document discusses various types of temperature and light stresses that can impact plants. It covers chilling injury that occurs between 0-10°C, freezing injury below 0°C, and heat stress from high temperatures. It also addresses light stress factors like light deficit, high intensity light, and ultraviolet radiation. The key effects of these stresses include membrane damage, protein degradation, inhibition of photosynthesis, and oxidative damage. Tolerant plants have mechanisms like heat shock proteins and screening compounds to better withstand these environmental stresses.
Seed dormancy allows seeds to remain dormant during unfavorable conditions until conditions become suitable for germination. There are two main types of dormancy - primary and secondary. Primary dormancy occurs due to internal factors like hormones, while secondary dormancy is caused by external factors like temperature. Dormancy can be overcome through methods like scarification, stratification, hormone treatment, and photoperiod manipulation. Seed dormancy provides important biological benefits like survival during drought or frost and dispersal to new areas.
This document discusses drought stress and the physiological traits that affect a crop's response to drought. It defines drought and categorizes it as agricultural, meteorological, or hydrological drought. It describes drought resistance mechanisms in plants like escape, avoidance, tolerance, and desiccation postponement or tolerance. It discusses various physiological traits that confer drought resistance, such as phenology, root architecture, leaf water potential, relative water content, stomatal conductance, anatomical modifications, oxidative damage response, osmotic adjustment, water use efficiency, osmolyte production, late embryogenesis abundant proteins, and more.
The document discusses various types of stress that can affect plants, including biotic stress from pathogens and abiotic stress from physical and chemical factors like drought, flooding, temperature extremes, light levels, salt levels, air pollution, wind, and nutrient deficiencies or toxicities. It describes how each stress can impact plant growth and physiology and outlines some strategies plants use to tolerate or avoid stress, such as escaping the stress period, avoiding stress through morphological adaptations, or tolerating stress through physiological and biochemical mechanisms.
- Chilling stress occurs in plants when they are exposed to temperatures above freezing, between 0-15°C. It can cause physiological disorders and injury.
- Symptoms vary between plant species but include wilting, water soaked lesions, leaf curling/crinkling, and reduced growth or death. This is due to impacts on cell membranes and metabolism.
- Plants native to warm climates are most susceptible, while those from cooler regions can acclimate to develop chilling tolerance through changes to lipid composition and protective compounds. Proper management can also help plants withstand low temperatures.
Antitranspirants and their effect on crop O.P PARIHAR
This document discusses antitranspirants and their effects on crops. It defines antitranspirants as compounds that reduce water loss through transpiration without significantly impacting plant growth or photosynthesis. There are four types of antitranspirants: stomatal closing, filmforming, reflecting, and growth retardants. The document provides examples of how antitranspirants have been shown to improve wheat, maize, barley and soybean yields under drought conditions by reducing water loss from the plants. However, it also notes that antitranspirants can potentially reduce photosynthesis and increase leaf temperatures if used.
This document discusses Zhou Yan's research interests in plant physiology, specifically stress physiology. It provides an overview of stress types in plants, including biotic, abiotic, chilling, freezing, heat, and drought stresses. It also discusses resistance mechanisms in plants, such as stress avoidance and stress tolerance. Zhou Yan's current research focuses on the effects of saline and alkaline stresses on soybean seedlings. The research examines impacts on growth factors and ionic balance, as well as the mechanisms plants use to adapt, such as osmotic regulation and ion regionalization.
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.
LEA(late embryogenesis abundant) protiens and heat shockBrahmesh Reddy B R
The document discusses abiotic stress in plants and the roles of late embryogenesis abundant (LEA) proteins and heat shock proteins. It states that LEA proteins accumulate in seeds during late development under drought stress and help protect plants from stress by stabilizing proteins and membranes. The document outlines various functions of LEA proteins, including protecting target proteins from damage, preserving membrane integrity, sequestering ions, acting as hydration buffers, and contributing to the formation of intracellular glasses that allow plant survival in dry conditions. It also notes that heat shock proteins help protect plants during stress by refolding proteins and maintaining homeostasis and membrane integrity.
Osmoregulation, and adaptation in plants against abiotic factors plant stres...Raheel Hayat Rahee
Osmoregulation allows organisms to maintain homeostasis by regulating water and electrolyte balance. It works through osmosis, where water moves across semipermeable membranes to areas of higher solute concentration. Organisms excrete excess water and solutes. Plants regulate osmoregulation through structures like stomata and use vacuoles and specialized adaptations depending on their habitat. Abiotic stress like drought, salinity, temperature extremes, and heavy metals can damage plants, but plants have developed tolerance mechanisms like avoidance, escape, and acclimation to survive environmental stresses.
Drought Tolerence in Plants and their Morph-Physiological, Biochemical and genetic adaptation to drought stress. Srategies to enhance drought tolerence.
This document provides a summary of a doctoral seminar presentation on metabolomics and the role of primary and secondary metabolites in plant response and adaptation to abiotic stress. The presentation covers different types of abiotic stresses plants face, how plants acclimate and adapt to stress conditions, and the role of various metabolites including amino acids, carbohydrates, polyamines, phenolic compounds, terpenoids, and nitrogen-containing compounds in stress tolerance. It also discusses crop adaptations to salinity stress and the mechanisms of salinity tolerance in plants.
Water stress & Signalling by Ujjwal Sirohiujjwal sirohi
Water deficit stress can negatively impact plant growth and productivity. Plants have developed several physiological responses and signaling pathways to cope with water deficit stress. These include closing stomata to reduce water loss, accumulating compatible solutes like glycine betaine to maintain cellular turgor under drought, and inducing transcription factors and receptor-like kinases that regulate stress-response genes. Abscisic acid plays a key role in triggering transcriptional changes that allow plants to adapt to water deficit conditions.
Drought tolerance in plants involves three main mechanisms: morphological, physiological, and genetic/molecular. Morphological mechanisms include drought escape and avoidance strategies like early reproduction or reduced water loss through waxy leaves. Physiological mechanisms regulate water use and loss, like stomatal closure and osmotic adjustment. Genetic and molecular mechanisms change gene expression, upregulating genes that produce proteins protecting cells from stress and regulating hormone signaling and transcription factors that control stress response pathways. Together these overlapping mechanisms help plants adapt and survive periods of low water availability.
The document discusses various drought resistance mechanisms in plants. It describes drought avoidance as maintaining high tissue water potential despite low soil moisture, while drought tolerance is withstanding water deficit with low tissue water potential. Plants use various adaptations to avoid or tolerate drought, including being water savers that conserve water or water spenders that rapidly absorb water. Water spender adaptations include accelerated water absorption, high root-to-top ratios, dew absorption, and some can convert to water savers in severe drought. Drought tolerance mechanisms discussed include osmotic adjustment, changes to cell wall properties, and stomatal closure at lower water potentials. The document also covers uncoupling of photosynthesis.
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.
EFFECT OF MOISTURE STRESS ON PLANT GROWTH AND DEVELOPMENTSHRAVAN KUMAR REDDY
Moisture stress can negatively impact plant growth and development through various mechanisms. Crops have developed different adaptations to moisture stress including escaping drought through short lifecycles, avoiding stress through water conservation or improved uptake, and tolerating stress. Avoiding stress involves mechanisms like reducing leaf area, increasing waxiness, and regulating stomata to conserve water or developing deep, branched root systems and high root to shoot ratios to improve water uptake. Tolerating stress includes osmotic adjustment to maintain turgor under water deficits. Understanding crop adaptations is important for managing plants under moisture stress conditions.
Transgenic approaches have been used to develop abiotic stress tolerance in plants. Genes introduced include those encoding osmoprotectants like proline and glycine betaine to protect cells during osmotic stress. Genes encoding antioxidant enzymes like superoxide dismutase have also been used to reduce reactive oxygen species during stress. Other genes introduced include late embryogenesis abundant proteins, transporters, heat shock proteins, and regulatory genes involved in abscisic acid response pathways. While initial work focused on single genes, more recent work aims to improve tolerance by modifying multiple metabolic or signaling pathways.
Moisture stress affects many aspects of plant growth and development including water relations, photosynthesis, respiration, anatomy, hormones, metabolism, nutrition, growth, development, reproduction and yield. Excess water can also be harmful by causing waterlogging and inhibiting aeration of soils. Crops develop various adaptations to moisture stress including avoidance through traits like deep roots or tolerance through osmotic adjustment. The ideal strategy is to avoid both moisture stress and excess water conditions.
The challenges of abiotic stress on plant growth and development are evident among the emerging ecological impacts of climate change, and the constraints to crop production exacerbated with the increasing human population competing for environmental resources.
These Slides will help you understand such stresses.
This document summarizes different biotic and abiotic stresses that affect cotton plants. It discusses various insect pests and diseases that are biotic stresses. It also describes several abiotic stresses including drought, low light, high temperature, waterlogging, and salinity. For each stress, it provides details on the effects on the cotton plant and examples of tolerant traits. It also discusses the use of transgenic cotton varieties containing Bt genes that provide resistance to certain insect pests.
Knox genes are the main genes involved in the regulation of development in compound leaves.
Whereas abiotic stress is the nonorganic type of stress.
This presentation ill help to get a brief idea about both the topics in a compressed form.
Environmental factors such as light, temperature, water, CO2 concentration, and wind can significantly impact plant and animal physiology. In plants, these factors influence processes like photosynthesis, transpiration, and membrane properties. Plants have various adaptations to respond to different environmental conditions, such as producing protective proteins in response to temperature extremes. Human physiology is also affected by the environment, particularly temperature, which the body regulates through thermoregulation and processes like sweating and shivering. Environmental stresses like heat and cold can impact the cardiovascular system as well as hydration levels. Animals also use changes in melatonin production in response to changes in day length as a seasonal clock.
Plants respond to environmental stresses through various mechanisms. Water stress leads to stomatal closure mediated by abscisic acid to reduce water loss. High light can cause photoinhibition of photosynthesis but plants repair damage to photosystem II through the D1 repair cycle. Temperature stress outside a plant's tolerance range disrupts membranes and proteins. Biotic stresses activate defense genes and pathogenesis-related proteins.
This document discusses how environmental factors affect the physiology of various living organisms. It covers how light, temperature, water, CO2 concentration, and wind impact plant physiology, influencing processes like photosynthesis, transpiration, and thermoregulation. It also explains how these environmental conditions affect the physiology of animals and humans, particularly their ability to regulate body temperature and combat heat and cold stress. Throughout, it provides examples of physiological adaptations that allow organisms to tolerate or avoid stressful environmental conditions.
Osmoregulation is the passive regulation of the osmotic pressure of an organism's body fluids, detected by osmoreceptors, to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration of electrolytes (salts in solution) to keep the fluids from becoming too diluted or concentrated.
The immediate and most common response by the different organs of a plant to water stress is decrease in turgor. This may be partially or fully adjusted by accumulation of solutes.
2. INTRODUCTION
• Drought is a period or condition of unusually dry weather within
a geographic area where there is a lack of precipitation.
• Drought is governed by various factors, the most prominent
being extremes in temperature, photon irradiance and paucity of
water.
• The characteristics features of drought stress is low water
potential due to high solute concentration.
• Low water supply causes soil mineral toxicities and can make a
plant more susceptible to damage from high irradiance.
• Affected area(s):Rajasthan, parts of Gujarat, Haryana and
Andhra Pradesh.
3. MECHANISM OF DROUGHT TOLERANCE
• DROUGHT ESCAPE: It is defined as the ability of a plant to
complete its life cycle before supply of water in soil is depleted and
form dormant seeds before the onset of dry season. These plants are
known as drought escapers since they escape drought by rapid
development.
• DROUGHT AVOIDANCE: It is the ability of plants to maintain
relatively high tissue- water potential despite a shortage of soil-
moisture. Drought avoidance is performed by maintenance of turgor
through roots grow deeper in the soil, stomatal control of
transpiration and by reduction of water loss through reduced
epidermal i.e. reduced surface by smaller and thicker leaves.
• DROUGHT TOLERANCE: It is the ability to withstand water-
deficit with low tissue water potential. Drought tolerance is the
maintenance of turgor through osmotic adjustment (a process which
induces solute accumulation in cell), increase in elasticity in the cell
and decrease in cell size.
5. Mechanisms of resistance to drought and the
methods to increase the resistance
1. Morphology: Increase in water absorption and transportation,
declination of transpiration
a. Developed root system and higher ratio of root to shoot.
b. Thick leaf, smaller leaf area and thick cuticle
c. Developed veins and bundle,smaller and more stomata
2. Physiology and biochemistry:
a. Stomatal regulation: ABA accumulation→stomatal closure
b. Increase in capacity of resistance to dehydration of
cytoplasm: Rapid accumulation of Pro, glycinebetaine, Lea
protein, dehydrin, osmotins and ion etc.
6. EFFECT OF DROUGHT STRESS
• Effect on Growth: Reduction in Turgor Pressure, due to cell
sizes will be smaller.
• Effect on Photosynthesis: Photosynthesis decreases due to
disruption of PS II (Photo System II), stomatal closure,
decrease in electron transport.
• Decrease in nuclear acids and proteins: Protease activity↑,
free aa↑, RNAase activity↑,RNA hydrolysis, DNA content
falls down.
• Effect on Nitrogen Metabolism: Nitrate reductase activity↓,
nitrite reductase activity insensitive
• Effect on Carbohydrate metabolism: Loss of starch and
increase in simple sugars, carbohydrate translocation decreases.
7. Synthesis of compatible solutes
• Almost all organisms, ranging from microbes to animals and
plants, synthesize compatible solutes in response to osmotic
stress.
• Compatible solutes are nontoxic molecules such as amino acids,
glycine betaine, sugars, or sugar alcohols which can
accumulate at high concentration without interfering with
normal metabolism.
• They may have a role in osmotic adjustment, stabilizing
proteins and cell structures, scavenging reactive oxygen
species.
8. • Proline is the most widely distributed osmolyte; it occurs in
plant and in many other organisms. Its accumulation correlates
with tolerance to drought and salt stress.
• Roles: Osmotic adjustment, membranes protection, a reservoir
of nitrogen and carbon source for post stress growth, sink for
energy to regulate redox potentials, OH• scavenger.
• Synthesis can occurs via two biosyntetic pathways:
The ornithine dependent, and
The glutamate dependent (predominant under stress
conditions).
Proline
9. Glycine Betaine(GlyBet)
Glycine betaine is a quaternary ammonium compound that
functions as an osmoprotectant. Its functions include:
Protects plant by stabilizing both the highly ordered quaternary
structure of proteins and membranes.
Refolding of enzymes as a molecular chaperone.
Maintenance of the water balance between the plant cell and
the environment and by stabilizing macromolecules.
Glycine betaine is synthesized via a two-step oxidation of
choline: Choline→betaine aldehyde→ glycine betaine. The
first reaction is catalyzed by a ferredoxin-dependent choline
monooxygenase (CMO) and the second step by a NAD+-
dependent betaine aldehyde dehydrogenase (BADH).
11. Late Embryogenesis Abundant (LEA) Protein
• Lea genes encode a diverse group of stress-protection proteins
expressed during embryo maturation in all angiosperms.
• Accumulation of LEA proteins during embryogenesis correlates
with increased levels of ABA and with acquisition of desiccation
tolerance.
• LEA proteins are not normally expressed in vegetative tissues but
they are induced by osmotic stress or exogenous application of
ABA.
• Evidence derived from expression profiles strongly supports a
role for LEA proteins as protective molecules, which enable the
cells to survive protoplasmic water depletion.
12. Engineering drought tolerance using transcription
factors (TFs)
• Conventional and transcriptome-based analyses have revealed
that dozens of transcription factors (TFs) are involved in plant
response to drought stress.
• These TFs are categorizes into large gene families like
AP2/ERF, bZIP, NAC, MYB, MYC, Cys2His2 zinc-finger and
WRKY.
• TFs regulates downstream genes which acting as a cis-elements
more directly act on drought response.
• Regulation pathways:
ABA-dependent: ABF/AREB TFs, acting on genes carrying the
ABRE element.
ABA-independent: CBF/DREB TFs acting on genes carrying
the CRT/DRE –C repeat/dehydration responsive-elements.
13. Transcriptional regulatory networks (cis-acting elements and transcription
factors) involved in osmotic and cold-stress responsiveness in Arabidopsis