Abiotic stress eng - [Download PDF]

RADIATION LACK OF WATER

INTENSITY OF LIGHT PLANT INJURY

EXTREME TEMPERATURES INFECTION OF PATHOGENS

OZONE INSECTS

Η2Ο2 Ο2-DESTRUCTION OF DNA

PROTEIN-LIPIDS

STOMATA CLOSE

GENES EXPRESION DESTRUCTION OF LEAVES

CELL WALL

HYPERSENSITIVE

RESPONSE

PEROXISOMES

BIOGENESIS

SCHEDULE

CELL DEATH

BIO-ABIOTIC STRESS

Abiotic stress:

1. Availability of water (drought, floods)

2. Temperature (hot, cold)

3. Salinity

4. O2 concentration

5. Limiting nutrients (N, P, micronutrients)

6. Pollution (air, i.e. ozone sulfur dioxide, ground i.e.

heavy metals)

7. Radiation (high, low)

8. The wind

ABIOTIC STRESS

Notability

Duration

Degree of exposure

Combination tensions

Characteristically

of intensityVegetable

characteristically

Effect Response

Survival development

Apoptosis –cell death

Resistance

Sensibility

Organ

or tissue

with problem

The stage of

development

Genotype

Abiotic

stress

ABIOTIC STRESS

Abiotic stress:

Abiotic stresses such as drought, salinity and mineral

toxicity negatively impact growth, development, yield

and seed quality of plants.

Similarly, large losses of grain yields in plants occur as

a result of pathogen attack, in particular during

vulnerable stages of grain development and

germination. Stress perception and plant response

occurs via signal transduction pathways that regulate

expression of several classes of stress responsive

genes. Products of these genes include those that are

directly involved in plant protection and those that fulfill

regulatory functions.

Abiotic stress:

The first group of the gene products include

chaperones, osmotins, anti-freeze proteins, mRNA

binding proteins, enzymes involved in osmolyte

biosynthesis, water channel proteins, sugar and proline

transport proteins, detoxification enzymes and a variety

of proteases, as well as a range of antimicrobial,

insecticidal and other proteins and peptides.

The proteins with regulatory function involve

transcription factors and those that are engaged in

signal transduction pathways, such as protein kinases

and hormone biosynthetic enzymes.

ABIOTIC STRESS

Unfavorable conditions

Stimulus concept

Signal transduction

Genes

expression

Synthesis of new

protein families

Metabolic

modifications

Answer

acclimatization

Modification

activity of

enzymes

Induced thermo

proteins

Depends on

Intensity of

stimulus

Changes in

genes

expression

Availability of water

ABIOTIC STRESS

ROS

S-HS=S

Oxydative

Cell death

LOO.DNA

-S=S-

Mild

Severity

damage

Proteins

Aminoacids

Lipids

ABIOTIC STRESS

1-5% of the total oxygen due to the process deviates

and converted into active forms of oxygen, which

causes metabolic effects,

and destruction of organic molecules such as DNA

lipids, proteins.

Especially chloroplasts favored by creating rich micro-

environment O2 at positions of the water photolysis

and photosystem II.

This fact, in conjunction with that chloroplasts are rich

in pigments makes them extremely sensitive targets.

ABIOTIC STRESS

and chloroplasts

.

Cytochrome

AREA

THYLAKOEIDOUS

ΑΤΡ

Η+Η+

Η+Ρι

e-

Η+

NADPHNADP

ΑDP

PS IIPS I

Η+

CALVIN

cycle

CO2Sugars

plastoquinone

PQ

FERREDOXINIS-NADPH reductase

CONVERSION COMPLEX

OFOXYGEN

Light

PC

Η+

e-

Ο2

H2OΗ+

Η+

ABIOTIC STRESS

and chloroplasts

ABIOTIC STRESS

and photorespiratory cycle

The redox potential leads nano-switches and stimulate cells through different biological stages

Cell division Cell differentiation Apoptosis Death

Ehc/mV

Off --Step

oxidation (+)

Step

reduction (-)

On -

Schafer and Buettner (2001)

ABIOTIC STRESS

and plant phases

. . . .4O

3OOC

2OSP

EE

D R

EA

CT

ION

Temperature

ABIOTIC STRESS

temperatures

The temperature disrupts the speed of enzymatic

reactions resulting of biochemical reactions that

take place slowly; to have the inactivation of

enzymes; also plant growth slows.

--1.Increase in cell size

Composition of cell wall

Conductance of stomata

Synthesis of protein

Effect on photosynthesis

Water potential MPa

--2. --3.

well

watered

medium

shortage

of water

Physiological changes caused by water potential.

Dehydration.

--4.

barren groundClean water

.

Concentration of of abscisic

Concentration of solutes

ABIOTIC STRESS

water economy

The role of potassium

H2O H2OH2O

H2O

H2O H2O

H2O

H2OH2O

K+

Epidermal

cells

ABIOTIC STRESS

water economy, stomata

K+

Ca++

Κ+

ABA

[Ca++]

Κ+

ABA

[Η+]

pH[K+]

[K+]

When the water supply is not consistent with the loss (transpiration)

swelling of the cells can not continue

the closure of the stomata is critical

and prevail the need to CO2 and ATP production.

Photosynthesis is inhibited partially or full.

ABA (abscisic acid); the phytohormone of stress

Suspension of

photosynthesis

Guard cell

ABIOTIC STRESS

water economy, stomata

The opening of stomata is regulated by internal factors such as macro-micro nutrients from the concentration of abscisic acid etc. and external humidity as lighting etc.

Amino acids have a positive effect on the opening of stomata (glutamate acts as an osmo-regulator in guard cells).

The metabolic balance of the plant is negative when the stomata are closed

and catabolism is higher than anabolism, growth of the plant stops

and a general decline of functions.

ABIOTIC STRESS

water economy, stomata

with increased cellular acidity and reduced amount of

antioxidants.

(as the fraction of oxidized glutathione to unbroken)

chloroplasts are present in the guard cells and the

amino acid

glutamate as precursor in the production of

chlorophyll and regulates plasmolysis opening-close

favoring opening stomata.

ABIOTIC STRESS

water economy, stomata

Amino acids have a positive effect on stomatal opening.

(glutamate acts as an osmo-regulator in guard cells)

Proline inhibits the action of abscisic and increases the

action of gibberellins.

When abiotic stress have increased acidity and reduced

cellular amount of antioxidants such as the fraction of

oxidized glutathione to opened glutathione.

ABIOTIC STRESS

and osmolytes

Many plants assemble betaines and proline at high

temperature, salinity and drought.

Lack of water leads to concentration of glycine betaine to

the leaves other small compounds that act as osmo-

regulators the amino acids is precursors in the

production of betaines (the hydroxyl groups of the

methylated)

Typical betaines, amino acids are alanine, proline,

glycine

ΓΛΥΣΙΝΗH

H

ΓΛΥΣΙΝΗCH3

CH3

Glycine betaineΓΛΥΣΙΝΗH

H

Glycine

ABIOTIC STRESS

and osmolytes

ANALYSIS OF TROUBLE BY SALINITY

What is the effect of salt concentration in plants and accumulation of amino acid proline;

Can these results support the hypothesis that plants accumulate proline to achieve osmotic balance in saline soils;

Accum

ula

tion o

f am

ino a

cid

ssalt concentration

Other aminoacidsproline

Graph of the level of amino acids in different

salinities.

ABIOTIC STRESS

and osmolytes

The effect osmotically active molecules (stored in the vacuole) Na +, K + to denaturation of the protein and the enzyme activity of the osmolyte proline (accumulates in cytoplasm)

Να+

Pro

Να+

Order hydration

Of protein

Disorder hydration

of protein

Proline and

operating configuration

Disorder functional configuration

Protein (Denaturation)

Pro