Visit https://www.slideshare.net/alihaider408/stress-and-osmoregulation-in-plantsedited for new edited version of the slide.
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.
Students able to understand that who helps to transport in plants, Mechanism of transport in plants, physical forces involved in transport, Behavior with different solutions.
Ecophysiological Effects of Changing Atmospheric Carbon Dioxide ConcentrationAsad Afridi
this presentation is about Carbon Dioxide. different effects of carbon dioxide are discussed in this presentation. such as effects on different plants, animals and environment.
intro-hostory and discovery-characteristics of phytochrome-chemical nature of phytochrome-mode of action-mechanism-phytochrome mediated physiological responses-phytochrome is a pigment system:some evidences-role of phytochrome
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
Everything about photoperiodism from scratch to smart, from the oldest models to the latest models as well as proposed one, exclusive and elusive illustrations and models for proper understanding
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 soil-plant-atmosphere continuum (SPAC) is the pathway for water moving from soil through plants to the atmosphere.
Continuum in the description highlights the continuous nature of water connection through the pathway.
The low water potential of the atmosphere, and relatively higher (i.e. less negative) water potential inside leaves, leads to a diffusion gradient across the stomatal pores of leaves, drawing water out of the leaves as vapour.
Students able to understand that who helps to transport in plants, Mechanism of transport in plants, physical forces involved in transport, Behavior with different solutions.
Ecophysiological Effects of Changing Atmospheric Carbon Dioxide ConcentrationAsad Afridi
this presentation is about Carbon Dioxide. different effects of carbon dioxide are discussed in this presentation. such as effects on different plants, animals and environment.
intro-hostory and discovery-characteristics of phytochrome-chemical nature of phytochrome-mode of action-mechanism-phytochrome mediated physiological responses-phytochrome is a pigment system:some evidences-role of phytochrome
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
Everything about photoperiodism from scratch to smart, from the oldest models to the latest models as well as proposed one, exclusive and elusive illustrations and models for proper understanding
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 soil-plant-atmosphere continuum (SPAC) is the pathway for water moving from soil through plants to the atmosphere.
Continuum in the description highlights the continuous nature of water connection through the pathway.
The low water potential of the atmosphere, and relatively higher (i.e. less negative) water potential inside leaves, leads to a diffusion gradient across the stomatal pores of leaves, drawing water out of the leaves as vapour.
Osmoregulation, and adaptation in plants against abiotic factors plant stres...Raheel Hayat Rahee
Osmoregulation in plants and adaptation in plants against abiotic factors
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In the intricate tapestry of nature, the relationship between plants and water is a fundamental aspect that influences the growth, development, and survival of flora. Plant water relations, a fascinating field of study, explores how plants absorb, transport, and utilize water in various physiological processes. In this comprehensive blog, we'll unravel the complexities of plant water relations, delving into the mechanisms that govern water movement within plants and the crucial role it plays in their overall well-being.
Osmoregulation Mechanisms and Adaptations in Various Organisms.pdfNAGENDRA SINGH
Osmoregulation is the process by which living organisms regulate the concentration of water and solutes (such as salts) in their bodies to maintain homeostasis, or a stable internal environment. This is especially important in aquatic organisms, which are surrounded by water of varying salt concentrations, but also in terrestrial organisms that need to conserve water.
In animals, osmoregulation involves a variety of physiological processes such as filtration, reabsorption, and secretion by the kidneys. Fish, for example, have specialized organs called gills that are adapted to exchange water and solutes with their environment. They also have kidneys that regulate the concentration of ions in their bodies. Other animals, such as birds, excrete waste products in the form of uric acid, which conserves water.
Plants also engage in osmoregulation, using a process called osmosis to absorb water and nutrients from the soil. They also use various mechanisms, such as opening and closing stomata, to control water loss through transpiration.
Overall, osmoregulation is an essential process for maintaining the internal environment of living organisms and ensuring their survival.
Sure, here are some additional details about osmoregulation:Types of Osmoregulation: There are two types of osmoregulation, depending on the organism's environment. In freshwater environments, organisms have to regulate the inflow of water and outflow of salts. In contrast, marine organisms have to regulate the outflow of water and inflow of salts.
Osmoregulatory Organs: Different organisms have evolved various osmoregulatory organs to maintain the balance of water and solutes in their bodies. For example, insects have Malpighian tubules, which remove waste and excess water from the body. Terrestrial animals such as reptiles, birds, and mammals have kidneys that filter blood and excrete waste products in the form of urine.
Osmolarity: Osmoregulation maintains the balance of osmolarity in the body, which is the concentration of solutes in a solution. Osmolarity is measured in units of osmoles per liter (osmol/L) and is important for the regulation of water balance in organisms.
Regulation of Salt Balance: In addition to regulating water balance, osmoregulation also involves the regulation of salt balance. Salt balance is critical for cellular functions such as enzyme activity, nerve function, and muscle contraction.
Osmoregulation and Adaptation: Different organisms have evolved various mechanisms for osmoregulation to adapt to their environment. For example, some desert animals conserve water by producing dry feces or uric acid instead of urea, which conserves water. Some marine organisms, such as sharks, have a high concentration of urea in their blood, which helps them retain water in the ocean's salty environment.
Osmoregulation and Human Health: Osmoregulation is essential for human health, and disruptions in the body's water and salt balance can lead to health problems such a
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
Coronaviruses & COVID 19 - Its Morphology, Role, Mechanism of Action, and Tre...Haider Ali Malik
Coronaviruses (CoV) are a large family of viruses transmitting between animals and people that cause illness ranging from the common cold to more severe diseases such as Middle East respiratory syndrome (MERS-CoV) and severe acute respiratory syndrome (SARS-CoV).
COVID-19 is a respiratory illness caused by a newly identified coronavirus, SARS-CoV-2
The current COVID-19 outbreak originated in Wuhan, China, in late 2019. World Health Organization (WHO) has been to characterized the outbreak as a pandemic on 11 March 2020. (WHO Bulletin 2020)
Heavy metals and its effects on plants and environmentHaider Ali Malik
Heavy metals are natural constituents of the earth’s crust , but indiscriminate human activities have drastically altered their geochemical cycles and biochemicals balance.
Any toxic metals may be called heavy metals.
Since heavy metals have a propensity to accumulate in selective body organs.
The average safety levels in food or water are often misleading high.
Heavy is any metal or metalloid of environmental concern.
Heavy metals are metallic element that have relatively high density usually greater than 5 g/cm3, or their density is greater than the density of water.
Modern Medical Application methodologies: Brachytherapy, Neutron Capture Ther...Haider Ali Malik
Brachytherapy (also referred to as Curie therapy) is defined as a short-distance treatment of malignant disease with radiation emanating from small sealed (encapsulated)
Neutron capture therapy (NCT) is a nonsurgical therapeutic modality for treating locally invasive malignant tumors such as primary brain tumors, and recurrent head and neck cancer.
Proton therapy, or proton radiotherapy, is a type of particle therapy that uses a beam of protons to irradiate diseased tissue, most often to treat cancer.
The USEPA defines biodegradation as a process by which microbial organisms transform or alter (through metabolic or enzymatic action) the structure of chemicals introduced into the environment.
According to the definition by the International Union of Pure and Applied Chemistry, the term biodegradation is “Breakdown of a substance catalyzed by enzymes in vitro or in vivo.
The term is often used in relation to ecology, waste management, biomedicine, and the natural environment (bioremediation) and is now commonly associated with environmentally friendly products that are capable of decomposing back into natural elements.
Biodegradable matter is generally organic material such as plant and animal matter and other substances originating from living organisms, or artificial materials that are similar enough to plant and animal matter to be put to use by microorganisms.
Phytoextraction, also called phytoaccumulation, phytoabsorption, or phytosequestration, refers to the use of plants to absorb, translocate, and store toxic contaminants from soil, sediments, and/or sludge in the root and shoot tissues .
Lead is an extremely difficult soil contaminant to remediate because it is a “soft” Lewis acid that forms strong bonds to both organic and inorganic ligands in soil. For the most part, Pb-contaminated soils are remediated through civil engineering techniques that require the excavation and landfilling of the contaminated soil. Soils that present a leaching hazard in the landfill are either placed in a specially constructed hazardous waste landfill, or treated with stabilizing agents, such as cement, prior to disposal in an industrial landfill.
Plants have adaptations to help them survive (live and grow) in different areas. Adaptations are special features that allow a plant or animal to live in a particular place or habitat. These adaptations might make it very difficult for the plant to survive in a different place.
This explains why certain plants are found in one area, but not in another. For example, you wouldn't see a cactus living in the Arctic. Nor would you see lots of really tall trees living in grasslands.
This presentation focuses on anatomical adaptations of three major types of plants: Hydrophytes, mesophytes and xerophytes.
Abiotic stress factors or stressors are naturally occurring, often intangible factors
The four major abiotic stresses: drought , salinity, temperature and heavy metals, cause drastic yield reduction in most crops.
Few of the types of abiotic stresses are:
1)Water-logging & drought
2)Excessive soil salinity
3)High or low temperatures
4)Ozone
5)Low oxygen
6)Phytotoxic compounds
8)Inadequate mineral in the soil
9)Too much or too little light
This presentation focuses on the adaptations in plants against abiotic stress and the ways that how they tolerate it with different mechanisms.
- Haider Ali Malik
Stelar System, Stele, its types and evolution(edited)Haider Ali Malik
Stele is defined as a central vascular cylinder, with or without pith and delimited the cortex by endodermis.
Van Tieghem and Douliot (1886) recognized only three types of steles.
1-Protostele
2-Siphonostele
3-Solenostele
Stelar Theory:
Major highlights of stellar theory are:
Stele is a real entity and present universally in all higher plants.
Cortex and stele are two fundamental parts of a shoot system
Stele and cortex are separated by endodermis.
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.
Protein targeting or protein sorting is the mechanism by which a cell transports to the appropriate positions in the cell or outside of it. Both in prokaryotes and eukaryotes, newly synthesized proteins must be delivered to a specific sub-cellular location or exported from the cell for correct activity. This phenomenon is called protein targeting. Protein targeting is necessary for proteins that are destined to work outside the cytoplasm.This delivery process is carried out based on information contained in the protein itself. Correct sorting is crucial for the cell; errors can lead to diseases. In 1970, Günter Blobel conducted experiments on the translocation of proteins across membranes. He was awarded the 1999 Nobel Prize for his findings. He discovered that many proteins have a signal sequence, that is, a short amino acid sequence at one end that functions like a postal code for the target organelle.
Mushrooms are nature's hidden treasures of nutrition. Many people like them for their satisfying meaty taste and their versatility. But are they really good for you? The answer is yes! In fact, you will be surprised to learn about the nutritional benefits of mushrooms. For thousands of years, mushrooms have been used in eastern medicine for their various health benefits.
The Shoot apex is also known as the terminal bud of plants that grows from 0.1-1.0 mm and consists of the apical meristem, developing leaves and the immediate surrounding leaf primordial. The shoot apex is present in both dicot and monocot plants.
The slides has been edited. visit for new one on https://www.slideshare.net/alihaider408/stelar-system-stele-its-types-and-evolutionedited-182037813
Sorry for inconvenience.
Stele is defined as a central vascular cylinder, with or without pith and delimited the cortex by endodermis.
Van Tieghem and Douliot (1886) recognized only three types of steles.
1-Protostele
2-Siphonostele
3-Solenostele
Stelar Theory:
Major highlights of stellar theory are:
Stele is a real entity and present universally in all higher plants.
Cortex and stele are two fundamental parts of a shoot system
Stele and cortex are separated by endodermis
The internet is the place where people around the world share information.
Addiction is the continued repetition of behavior despite adverse consequences leading to such behaviors.
A mobile phone is an electronic device used to make mobile telephone calls across a wide geographic area
In addition to being a telephone , modern mobile phones also support many additional services such as SMS, e-mail, internet access, gaming, Bluetooth, infrared, camera, MMS messaging, MP3 player, radio and GPS
Mobile phones were first developed in 1946
Multimedia is a computer-based interactive communications process that incorporates text, graphics, sound, animation, and video
The term is used in contrast to media which only use traditional forms of printed or hand-produced material.
A port is the point at which a peripheral attaches to or communicates with a system unit (sometimes referred to as a jack)
while a connector is any connector used within computers or to connect computers to networks, printers or other devices.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
2. Stress
Biological stress is not easily defined but it implies adverse
effects on an organism
Like all other living organisms, the plants are subjected to
various environmental stresses such as water deficit and
drought, cold, heat, salinity and air pollution etc.
3. Stress is any change in environmental conditions that might reduce or adversely change
plant’s growth and development (Levitt, 1972)
Adverse force or influence that tends to inhibit normal systems from functioning (Jones,
1989)
Any situation where the external constraints limit the rate of dry matter production of all or
part of the vegetation below its ‘genetic potential’ (Grime, 1979)
Therefore, most practical definition of a biological stress is an adverse force or a
which inhibits the normal functioning and well being of a biological system such as
4. Stress terminology
Stressor/Stress factor:
Any factor that causes injury or stress stimulus
Stress response:
Stress stimulus with ensuing state of adaptation
Eustress:
It is an activating, stimulating stress that increase the physiological activity of a plant and thus
a positive element for plant development.
5. Distress:
It is a severe and a real stress that causes damage and thus has a negative effect
the plant and its development.
Zero stress:
The stress that is just insufficient to produce a plastic strain.
Stress resistance:
Ability of the plant to survive under adverse environmental condition is termed as
stress resistance (adaptation, avoidance and tolerance).
6. Elastic resistance:
Ability of the plant to prevent reversible or elastic strain (physical or chemical change) when
exposed to a specific stress
Adaptation
It refers to heritable modifications in structure or function that increase the fitness of the
organism in the stressful environment. It is also called protection. e.g. CAM plants to desert
Acclimation
It refers to non-heritable physiological modifications that occur over the life of an individual.
modifications are induced by gradual exposure to the stress. The process of acclimation is known
hardening
7. Damage/Stress injury:
It is the result of too high a stress which can not be compensated.
Dehydration :
The loss of water from a cell. Plant cells dehydrate during drought or water
deficit.
Desiccation :
The extreme form of dehydration. Denotes the process whereby all free water
lost from the protoplasm.
8. Homoiohydry : Water economy strategy whereby plants strive to maintain a
high water potential under water limiting conditions. Homoiohydric plants
drought avoidance.
Poikilohydry : Water economy strategy whereby plants lack the ability to control
water loss to the environment. Poikilohydric plants must be drought tolerant.
Poikilotherms: Plants that tend to assume the temp. of their environment i.e they
must develop temp. tolerance
9. Effect of stress on plants
There are no specific osmoregulatory organs in higher plants, the stomata are the only important
structures rake part in regulating water loss through evapotranspiration, and on the cellular level
the vacuole is crucial in regulating the concentration of solutes in the cytoplasm.
Strong winds, low humidity and high temperatures all increase evapotranspiration from leaves.
Abscisic acid is an important hormone in helping plants to conserve water—it causes stomata to
close and stimulates root growth so that more water can be absorbed.
Plants share with animals the problems of obtaining water but, unlike in animals, the loss of water in
plants is crucial to create a driving force to move nutrients from the soil to tissues. Certain plants
have evolved methods of water conservation.
10. 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.
Plants growing under conditions of high salinity accumulate various solutes as a
result of alterations in intermediary and secondary metabolism of nitrogen or of
carbon (Greenway and Munns, 1980; Stewart and Larher, 1980).
This results most probably from an imbalance in the inorganic ion status ultimately
causing a malfunctioning of the enzymes involved.
Amides, free amino acids, proline, amines, quaternary ammonium compounds and
sugars are some of the organic solutes that show a change in their accumulation
under condition of stress (Hsiao, 1973; Stewart and Larher, 1980).
11. It has been suggested that high concentrations of organic solutes in the
cytoplasm play a double role (Greenway and Munns, 1980):
They can contribute to the osmotic balance when electrolytes are lower in the
cytoplasm than in the vacuole and
They can have a protective effect on enzymes in the presence of high
electrolytes in the cytoplasm. However, there remains speculation about the
primary roles of these solutes, viz., whether it is one of storage of reduced
carbon and/or nitrogen, or in the osmotic balance of the cell as a whole
(Greenway and Munns, 1980).
12. Stress
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.
13. Introduction
The protoplasm of living organisms has a high percentage of water, so without
water, living organisms would die.
Plants living in water, or those in hot, arid conditions where water is not readily
available all the time, or in which there is a high concentration of solutes such as
occurs in/near sea water, must adapt their structure and/or their various functions
– or both – to ensure the conservation of needed water and prevent the upset of
the osmotic balance of cell contents.
Without the right osmotic balance – the plant dies!
14. Surviving the salt
These Mangroves grow in wet,
muddy soil at the sea -water's edge.
If you look at the leaves, salt crystals
are excreted on to their surfaces,
and if you taste the sap – it’s very
salty!
15. Surviving the salt
Some mangroves are almost covered by salty sea water!
Most trees cannot survive in
water that has too much salt in it,
but mangrove trees have a
unique adaptation for dealing
with the sea's salinity.
16. Surviving the salt
When they’re submerged in sea water, warty growths on
mangrove roots filter out most of the salt as they take water in
through their roots.
Some mangroves concentrate extra salt in old leaves (which
turn yellow and die), and some are able to get rid of the salt by
secreting it through the pores of special glands.
17. Surviving drought
In contrast to mangroves, plants, such as
these cacti and Acacia that live in places
like along the Palisadoes strip or in the
Hellshire area, grow in limited, dry,
sandy soil, with little rainfall, a very high
temperature and a hot, dry wind.
18. Some water conservation methods
Succulent plant stem
(Cactus)
Succulent leaves of Sesuvium & Aloe
19. OSMOREGULATORY ADAPTATIONS
The plants shown on the previous slides have adaptations that
ensure osmoregulation.
Osmoregulation is the active regulation of the osmotic pressure
of an organism’’s fluids to maintain the homeostasis (or constant
unchanging balance) of the organism’s water content; that is, it
keeps the organism's fluids from becoming too diluted or too
concentrated.
20. OSMOREGULATORY ADAPTATIONS
Plants such as mangroves
develop structural and
physiological adaptations to
regulate the osmotic balance of
their cell contents – i.e to carry
out osmoregulation.
The cacti and other plants living
along the hot, dry scrubland of
the Palisadoes strip also develop
special adaptive features for
osmoregulation.
21. OSMOREGULATION AND STRESS PARADIGM
IN PLANTS
Drought and salinity stress are the major causes of historic and modern agricultural
productivity losses throughout the world.
Both drought and salinity result in osmotic stress that may lead to inhibition of
growth. Salinity causes additional ion toxicity effects mainly through perturbations
in protein and membrane structure.
In contrast to animals, which rely on Na1/K1-ATPases for the expulsion of osmotica,
plants rely on plasma membrane and endosomal ATPase activities to generate
proton gradients to drive ion extrusion and intracellular sequestration.
22. OSMOREGULATORY MECHANISMS IN
PLANTS
Consequently, most angiosperms, including all major crop species, have a
diminished capacity for Na1 transport and tolerance to high salinity.
The chemiosmotic regulatory systems of plant and fungal cells differ
fundamentally from those found in animal cells.
Animal cells rely on a primordial Na1 chemiosmotic circuit consisting of Na1/K1-
ATPase ‘‘pumps’’ to drive the efflux of 3Na1 and influx of 2K1 coupled to ATP
hydrolysis.
This active Na1 extrusion creates an electrochemical Na1 gradient across the
plasma membrane to drive secondary symport and antiport carriers that, in
turn, regulate nutrient uptake and pH.
23. In contrast, plants appear to lack plasma membrane Na1/K1- ATPases. Thus, plants
utilize H1-ATPases for primary extrusion or sequestration of protons to generate H1
electrochemical gradients, which drive secondary ion and nutrient transport processes
via H1-symport/ antiport systems. These H1-ATPase pumps also modulate both
intracellular and extracellular pH.
Except in the case of extreme halophytic archaebacteria, viable cellular processes in
animals, fungi, and plants depend upon the maintenance of low cytoplasmic Na1 and
Cl2 concentrations and a high K1/Na1 ratio, because K1 counteracts the inhibitory
effects of Na1 (and Li1).
Like animal cells, most plant cells maintain cytosolic K1 concentrations in the range of
100–200 mM and Na1 values in the low mM range (1– 10 mM) up to a maximum of
100 mM.
24. In contrast to K1, an essential cation for maintaining biochemical interactions of
the cytoplasm, Na1 is not essential for, but does facilitate, volume regulation and
growth in most plants. However, at high concentrations Na1 limits growth.
Ironically, the productivity of irrigated agricultural regions is generally many times
greater than non-irrigated areas, yet irrigated crops are most susceptible to
detrimental salinity effects.
Therefore, genetic engineering of crop plants to improve their capacity for Na1
transport and sequestration is an important goal for meeting the future food and
fiber demands of a rapidly growing human population.
25. Many plants, such as extreme halophytes, display Na1 dependence for optimal
growth and development and have developed specialized structures such as salt
glands and bladders to accommodate high salt concentrations in tissues. Others
have developed whole plant strategies for avoiding stress such as accelerated
completion of ontogeny.
However, these specialized adaptations are lacking in most major crop species.
Furthermore, the precise impact of osmotic and ionic effects on cell growth,
division, phytohormone balance, and death in the context of the whole plant are
complex and require further investiga
26. Osmoregulatory adaptations – Types of
plants
Depending on their habitat, plants can be grouped into four different types
according to the osmoregulatory adaptations that they show either in their
structure, functions, or both.
Groups are as follows:
Halophytes
Hydrophytes
Xerophytes
Mesophytes
27.
28. Examples
(a) mangrove = halophyte
(b) Catus = xerophyte
(c ) an ackee tree = mesophyte
(d) water lily = hydrophyte
The leaves float on the water surface and numerous stomata are present on the
upper surface of the leaves facing the atmosphere to promote loss of water. The
surface area of these leaves is very large to enable excessive water loss by
transpiration
29. Why is osmoregulation important to plants?
1) Enables the plant to grow, develop, carry on respiration, photosynthesis and survive, even if:
the habitat is dry, hot and desert-like.
sandy/rocky soil does not hold much water.
rainfall is scarce or only at certain times.
adequate water is not available for photosynthesis and
hydration of the cell contents.
habitat is completely aquatic.
salinity of the habitat is high.
2) It regulates and balances the uptake and loss of water and solutes so maintains homeostasis.