Cai shumei

transcript

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Cai Shumei 蔡树美

Phosphorus Absorbing Efficiency Discrepancy

of Duckweed under Different Influence Factors

Dept. of Bioscience & Biotechnology

Yangzhou University

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Backgrounds

In Vitro Experiment

Results & Discussion

Conclusions

Outline

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Backgrounds

Harm of Water Eutrophication ：

滇池蓝藻暴发

Muddy Water Appearance;

Bad Smell;

Dangerous Microcystins;

Dying of Aquatic Organisms. 太湖鱼类死亡

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Phosphorus!!!

Nitrogen

Water Eutrophication

……

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PhosphateAbsorption

Mechanism of plants’ Phosphorus Absorption

MembraneTransport protein

Ion channelIon channel CarrierCarrier

Diffusion

Activetransport

H+-ATPaseH+ATP+H2O

ADP+Pi

OH-+ ADP

PhosphateCarrier

H2PO4-

HPO42-

H2PO4-

Ion channelIon channelIon channelIon channelIon channelIon channel CarrierCarrierIon channelIon channel CarrierCarrierIon channelIon channel CarrierCarrierCarrierCarrierIon channelIon channel CarrierCarrier

CarrierCarrier

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Advantages of Duckweed for Phosphorus-Containing Wastewater Treatment

Strong Phosphorus Absorptive Capacity;

Fast Growth Rate;

Easy for Reaping;

High Protein Animal Feed;

No Secondary Pollution.

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In Vitro Experiment

Factors affecting Pi uptake rate :

• Genotype ；

• Photon flux density ；

• Temperature ；

• pH;

• Phosphorus concentration.

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25 ℃

3000 lx

20 Fronds

Hoagland’s E-Medium culture

Cultivate Parameters:

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Duckweed genotypes

Spirodela

Wolffia

Results & Discussion浮萍属

芜萍属

紫萍属

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Duckweed Size

L: Lemna S: Spirodela W: Wolffia

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Genotypes Biomass increase（ g）

Total Pi uptake（ mg）

Pi uptake rate(mgPi/gFW)

L. aequinoctialis 3.197±0.327aA 3.382±0.010aA 1.066±0.112aA

S. oligorrhiza 1.684±0.037bB 3.312±0.003bB 1.967±0.045bB

S. polyrrhiza 1.663±0.063bB 3.336±0.005cC 2.008±0.077bB

Tab.1 Phosphorus absorbency comparison of different duckweed genotypes

The English capital letter and lowercase expressed the mean difference is significant at the .01 and .05 level in the treats.

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Fig.1 The relationship between pi uptake rate and its concentration in solution

（ a: L. aequinoctialis ， b: S. oligorrhiza ， c: S. polyrrhiza ）

0 0.5 1 1.5 2 2.5 3

外Pi浓度（mmol/L）

吸收

速率

（μm

ol/g 鲜

重•h

0 0.5 1 1.5 2 2.5 3

Pi mmol / L外浓度（）

0 0.5 1 1.5 2 2.5 3

外Pi浓度（mmol/L）

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Genotypes Kinetic Equation R2 Km(μmol/

Vmax(μmol/

gFW•hr)

L. aequinoctialis

S. oligorrhiza

S. polyrrhiza

I=5C/ (1.25+C)

I=7.698C/ (2.186+C)

I=9.606C/ (2.695+C)

0.971**

0.966**

0.987**

Tab.2 Kinetic parameters of Pi uptake by different genotypes of duckweed

**: the siginificant were at 1% level.

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Fig. 2 Ultrastructure of chloroplasts in mesophyllic cells of different duckweed genotypes

（ a: L. aequinoctialis×18500 ， b: S. oligorrhiza×26500 ， c: S. polyrrhiza×26500）

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10 20 30

培养时间（天）

U/gprot

酶活

力（

L. aequi noct i al i sS. ol i gorrhi zaS. pol yrrhi za

Fig. 3 ACP activities of different duckweed genotypes

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Spriodela had a higher phosphorus uptake capacity, though

it’s growth rate was lower than the Lemna;

Phosphorus uptake kinetics in duckweed were in accord with

the Michaelis-Menten equation;

Conclusions

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The Km value for Pi uptake of Lemna aequinoctialis was less

than that of Spirodela oligorrhiza and Spriodela polyrrhiza,

making it a better candidate for treating wastewater with a

lower Pi concentration；

The Vm value of phosphorus uptake by Spriodela polyrrhiza

was higher than that of the other two genotypes , which

might lead to a better performance of Spriodela polyrrhiza in

purifying wastewater with a higher Pi concentration;

Conclusions

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Compared with Lemna, leaf chloroplast morphology of

Spriodela promoted the export of assimilation products;

ACP activity of Spriodela was higher than that of Lemna,

which also indicated Spriodela may have a higher

phosphorus uptake capacity.

Conclusions

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Cai shumei

Education