Enhancement by Enhancement by HydrogelHydrogel Polymers of Salt Polymers of Salt Resistance in PoplarResistance in Poplar

Shaoliang ChenShaoliang Chen

College of Biological Sciences and Technology, Beijing Forestry College of Biological Sciences and Technology, Beijing Forestry University, University, Beijing 100083, PR ChinaBeijing 100083, PR China

InstitutInstitut ffüürr ForstbotanikForstbotanik, , GeorgGeorg--AugustAugust--UniversitUniversitäätt GGööttingenttingen, , BBüüsgenwgsgenwg 2, 2, 37077, 37077, GGööttingenttingen, Germany, Germany

Beijing, Oct 29th, 2008Beijing, Oct 29th, 2008

The 23rd Session of the International Poplar Commission

Soil salinization is severe Soil salinization is severe in China and salinein China and saline--alkali alkali land is approximately 30 land is approximately 30 million hectares, which is million hectares, which is mainly distributed in the mainly distributed in the north of Yangtze River. north of Yangtze River.

China ThreeChina Three--North Plantation ProjectNorth Plantation Project

Soil Soil salinizationsalinization

StockosorbStockosorb polymerpolymer

Stockhausen GmbH, Stockhausen GmbH, KrefeldKrefeld, Germany, Germany

HydrogelHydrogel increased salinity tolerance of increased salinity tolerance of P. P. euphraticaeuphratica ⎯⎯A 2A 2--year experiment in year experiment in GGööttingenttingen Univ. GermanyUniv. Germany

HydrogelHydrogel amendment:amendment:

Potassium mine refuse in Potassium mine refuse in BischofferodeBischofferode(Germany)/abundant with (Germany)/abundant with NaClNaCl

0.6% (0.6% (v/vv/v) ) StockosorbStockosorb K410, K410, which is a highly which is a highly crosslinkedcrosslinkedpolyacrylamidepolyacrylamide with about with about 40% of the amide group 40% of the amide group hydrolysedhydrolysed to carboxylic to carboxylic groups.groups. + 2.7-fold biomass

Effects of Effects of hydrogelhydrogel on on cellular ion relations (by cellular ion relations (by EDAX): EDAX):

restricted restricted apoplasticapoplastic NaNa+ + in in young and old rootsyoung and old rootslimited limited apoplasticapoplastic and and cytoplasticcytoplastic ClCl-- in old roots in old roots increased increased ClCl--compartmentationcompartmentation in in cortical vacuolescortical vacuolesenhanced uptake of Caenhanced uptake of Ca2+2+

HydrogelHydrogel--covered rootscovered roots

Chen S, et al. 2004. Chen S, et al. 2004. Trees 18, 175Trees 18, 175--183.183.

ObjectivesObjectives

Is the polymer working in salt soil in China?Is the polymer working in salt soil in China?

Is the polymer able to enhance salinity Is the polymer able to enhance salinity tolerance of salttolerance of salt--sensitive poplars?sensitive poplars?

Experimental treatmentsExperimental treatments

Two species: Two species: P. euphratica, P. popularisP. euphratica, P. popularis

Control Control ±± hydrogelhydrogelNaClNaCl −− hydrogelhydrogelNaCl + hydrogelNaCl + hydrogel

Hydrogel:Hydrogel: StocksorbStocksorb 500 XL, 0.5% (v/v)500 XL, 0.5% (v/v)NaCl :NaCl : Addition of 1L 250 mM NaCl to 10 L Addition of 1L 250 mM NaCl to 10 L

soil/per pot, reaching a final concentration of soil/per pot, reaching a final concentration of ca. 55 mM in soil solutionca. 55 mM in soil solution

Plant response to salinityPlant response to salinity

处理处理TreatmentTreatment

胡杨胡杨PP．．euphraticaeuphratica

群众杨群众杨PP．．popularispopularis

ControlControl

NaClNaCl

NaCl + hydrogelNaCl + hydrogel

NormalNormal

NormalNormal

NormalNormal

NormalNormal

Injured/25dInjured/25d

Injured/45dInjured/45d

Salt injurySalt injury ⎯⎯ P. P. popularispopularis

NaCl + hydrogel

NaCl − hydrogel

Unit transpiration rateUnit transpiration rate

0

2

4

6

8

12 18 25

蒸腾

速率

(TR

N)/m

mol

.m-2.s

-1

Tran

spira

tion

rate

/mm

ol.m-2

.s-1

controlNaClNaCl and hydrogel

0

2

4

6

8

12 18 25

controlNaClNaCl and hydrogel

胡杨 群众杨P．euphratica P．popularis

Time/d Time/d

0

100

200

300

12 18 25

气孔

导度

(GS)

/mm

ol.m-2

.s-1

Stom

atal

con

duct

ance

/mm

ol.m-2

.s-1 control

NaClNaCl and hydrogel

0

100

200

300

12 18 25

controlNaClNaCl and hydrogel

Time/d Time/d

胡杨 群众杨P．euphratica P．popularis

StomatalStomatal conductanceconductance

0

2

4

6

8

10

12

12 18 25

time/d

净光

合速

率(P

n)/μ

mol

.m-2

.s-1

Net

pho

tosy

nthe

tic ra

te/μ

mol

.m-2

.s-1 control

NaClNaCl and hydrogel

0

2

4

6

8

10

12

12 18 25time/d

controlNaClNaCl and hydrogel

胡杨 群众杨P．euphratica P．popularis

Net photosynthetic rateNet photosynthetic rate

Leaf ion concentrations Leaf ion concentrations ((mmolmmol gg--11DW)DW)

树种species

处理Treatment Cl- Na+ K+ Ca2+ Mg2+

胡杨

P． euphratica

群众杨

P． popularis

Control

NaCl

NaCl + hydrogel

Control

NaCl

NaCl + hydrogel

0.22c

0.52a

0.38b

0.20c

1.16a

0.64b

0.05c

0.23a

0.16b

0.03c

0.48a

0.27b

0.53a

0.42b

0.56a

0.38b

0.41b

0.50a

0.09a

0.08a

0.07a

0.10a

0.10a

0.10a

0.17a

0.16a

0.15a

0.18a

0.18a

0.19a

Soil ion concentrations (Soil ion concentrations (mMmM))

处理Treatment Cl- Na+ K+ Ca2+ Mg2+

Control

NaCl

NaCl and hydrogel:⎯ Soil⎯ Hydrogel granules

Hydrogel products

14.2d

64.1a

39.7b29.9c

0.2e

7.0c

48.9a

36.6b2.7d

1.7e

4.4b

1.0c

4.5b0.8c

6.8a

8.3a

7.9a

7.8a1.5b

0.1c

12.3a

10.5a

12.3a2.1b

0.3c

Root aggregation in Root aggregation in hydrogelhydrogel granulesgranules ⎯⎯ P. P. popularispopularis

NaClNaCl + + hydrogelhydrogel

NaClNaCl −− hydrogelhydrogel

Root aggregation in Root aggregation in hydrogelhydrogel granulesgranules ⎯⎯ P. P. euphraticaeuphratica

NaClNaCl −− hydrogelhydrogel

NaClNaCl + + hydrogelhydrogel

RootRoot--shoot salt transport regulationshoot salt transport regulation

Is the polymer working in salt Is the polymer working in salt soil in China?soil in China?

⎯⎯Yes.Yes.Is the polymer able to enhance Is the polymer able to enhance salinity tolerance of saltsalinity tolerance of salt--sensitive poplars?sensitive poplars?

⎯⎯Yes.Yes.

HydrogelHydrogel effects:effects:Salt buffering capacitySalt buffering capacityNutrient source, e.g. KNutrient source, e.g. K++

Na+, Cl-

AcknowledgementsAcknowledgementsInstitut fInstitut füür Forstbotanik der r Forstbotanik der

UniversitUniversitäätt GGööttingenttingen

Prof. Dr. Prof. Dr. AloysAloys HHüüttermannttermannProf. Dr. Andrea PolleProf. Dr. Andrea PolleDr. Dr. EberhardEberhard FritzFritzMs. Karin LangeMs. Karin LangeMr. Mr. MoitabaMoitaba ZommorodiZommorodiMr. Mr. KonradKonrad WehrWehrMs. Christine Ms. Christine KettnerKettner

Beijing Forestry UniversityBeijing Forestry University

Prof. Shasheng WangProf. Shasheng WangMs. Ms. JinkeJinke Li Li Mr. Mr. JieJie ShaoShaoMr. Yong ShiMr. Yong ShiMr. Mr. JianJian SunSunDr. Dr. RuigangRuigang WangWang

The Hebrew University of The Hebrew University of JerusalemJerusalem

Prof. Dr. Prof. Dr. ArieArie Altman Altman

Structure of Structure of acrylamideacrylamide-- potassium potassium acrylateacrylate crosslinkedcrosslinked polymers polymers

Model of swelling gelModel of swelling gel

The The ““Silk Road Silk Road ”” TourTour

Populus euphraticaPopulus euphratica Oliv.(Oliv.(胡杨胡杨))

(Chen et al. 2001, 2002a, 2002b, 2003, 2004, Chang et al. 2006, Wang et al. 2007, 2008)

receptorPM

PM

Na+, Cl-

Na+,Cl-

Vacuole

Gene expression

Na+

H+

H+

Cl-

antioxidantenzymes

Ion compartmentation

ABA,Ca2+, CaM,

H2 O2

Na+

H+H+ K+,Na+ Cl-

ROS

SOD (SOD (superoxidesuperoxide dismutasedismutase) ) isoenzymesisoenzymes

P. euphratica P. popularisS S+H C S S+H C

SOD1

SOD2

SOD3

POD1

POD2

POD3

POD4

POD5

POD6

P. popularis P. euphraticaC S+H S C S+H S

S: NaCl; S+H: NaCl+hydrogel; C: control

POD (POD (peroxidaseperoxidase) ) isoenzymesisoenzymes