Zhou YanZhou YanSchool of Life Science NENUSchool of Life Science NENUEmail:zhouy006@nenu.edu.comEmail:zhouy006@nenu.edu.com

Stress PhysiologyStress Physiology

Plant PhysiologyPlant Physiology

Study the laws of plant life activities

Contains ◇ growth 、 development and morphogenesis ◇ material and energy transformation ◇ message transportation 、 signal transduction

Growth 、 development and morphogenesis

the external appearance of plant life

Material and energy transformation the basis for growth and development

Message transportation and signal transduction

an important part of plant adaptation to the environment

Stress ： Environmental damage to plants ◇ Biotic stress ◇ Abiotic stress

Resistance ： The adaptability of plants to adverse environment

◇Stress avoidance ◇ Stress tolerance

Stress Physiology ： adversity makes an impact on plant life activities, resistance of plants to adversities

Plant Physiology in Environment StressPlant Physiology in Environment Stress

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Types Types oo f f SS tresstress

Biotic stress ◇ pathogen stress Abiotic stress ◇ chilling stress ◇ freezing stress ◇ heat stress ◇ wet stress ◇ flood stress ◇ drought stress ◇ salt stress

temperatures stress

water stress

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Types Types oo f f ResistanceResistance

stress avoidance In the whole growth process does not meet with

the face of adversity

stress tolerance Plant has a capacity of environmental stress

defense, and a variety of physiological processes remain normal

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We all know one of the major reasons of soil degradation ,land resources shortage and ecological environment worse is land salt-alkalization

Distributionland surface:13.2×109 hectarearable lands:7×109 hectare cultivated lands:1.5×109 hectaresaline soil:0.34×109 hectare (23%)alkaline soil: 0.56×109 hectare (37%)

salinization of soil

main cation: Na+,Ca2+,Mg2+, K+

main anion: Cl-, SO42-, HCO3

-,CO32-, NO3

-

main salt NaCl, Na2SO4 ,Na2CO3, NaHCO3

saline soil: NaCl, Na2SO4 in soil

alkaline soil: Na2CO3, NaHCO3 in soil

saline-alkaline soil

soybean

Salt stress is one of the major abiotic stresses, depress plant growth and limit crop production. Because of the increasing salinization in soils, it has been a great threat to crop productivity.

Soybean is one of the main crops in China. It is important for agriculture application and plant improvement that we can understood the mechanism for its response to salt stress.

Cultivated soybean salt-sensitive but high yield breedWild soybean salt-tolerant but low yield breedSemi-wild soybean has been selected between cultivated

soybean and wild soybean A stable somatic descendent has been proved to

have inherited salinity-resistant traits

In order to address the growing problem of utilizing salinized and alkalized lands, halophytes have been studied as the principal species for exploiting and recovering saline-alkalinized soil.

An increasing number of reports on distribution, exploitation, and physiological mechanisms of saline resistance of halophytes have been published.

However, few studies have been done on the alkaline resistance especially cultivated

soybean . In fact, soil salinization and alkalization

frequently co-occur, and this has caused severe problems in some areas.

In northeast China, alkalinized grassland covers more than 70% of land area, and is expanding.

salt stress

The main point I've been studying is the effects of saline and alkaline stresses on growth and ionic balance of cultivated soybean seedlings

salt stress ◇neutral salt stress ◇ alkaline salt stressalkali-stress (A) salt-stress (S)

My work

Growth ◇germination rate ◇ root length ◇ water content ◇ fresh weightionic balance◇ anion:◇ cation:

Mechanism disordered In these pictures we can find the variation

tendency of ion content of alkali-stress (A) is more striking than salt-stress (S) except the chlorine ion and sulfate ion.

the deleterious effects of salt stress result primarily from osmotic stress and ion toxicities. But, under alkaline stress, the salinized soil contains HCO3

- and CO32-, in addition to osmotic

stress and ion toxicities, plants also have to deal with stress of high pH.

Osmotic regulation

Ion regionalization

The mechanism for Plant AdaptationThe mechanism for Plant Adaptation

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Osmotic regulation◇ reduce volume◇ reduce water content◇ absorb the inorganic ions in vacuole Na+ 、 K+ 、 Ca2+ 、 Mg2+ 、 Cl- 、 SO4

2- 、 NO3-

◇ synthetic organics accumulate in the cytoplasm proline 、 soluble sugar 、 organic acid 、 betaine

Ion regionalization

As a result of intracellular ion balance, a stable tissue pH is necessary for plants to maintain normal metabolism. In a living plant, as long as the plant can adapt to the environment, the pH value in its tissue should be stable regardless of how the environmental pH value changes.

High-salt environments can break the ion homeostasis of plant cells, destroy the ion balance. Under salt stress, it is necessary to osmotically adjust and re-establish the ion balance in cells for plants living.

Plants regulate the intracellular pH to keep ion balance by ion regionalization

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InterestingInteresting

ⅰ Membrane permeability

ⅱ Permeability regulator content

ⅲ MDA content

ⅳ SOD 、 POD 、 CAT activityⅴ The degree of succulent plant tissueⅵ Plant tissue water potentialⅶ Water content

ⅷ Osmoregulation material ⅸ Ion content