Use of Mixture Use of Mixture Experiments to Experiments to

Determine the Effect of Determine the Effect of Counter-cations of HCOCounter-cations of HCO33

-- on Bean (on Bean (Phaseolus Phaseolus

vulgarisvulgaris L.) ‘Poncho” in L.) ‘Poncho” in HydroponicsHydroponics

Luis A. Valdez-A. and David Wm. ReedLuis A. Valdez-A. and David Wm. ReedDept. of Horticultural SciencesDept. of Horticultural Sciences

Texas A&M UniversityTexas A&M University

BicarbonateBicarbonate Major contributor to alkalinityMajor contributor to alkalinity

HCOHCO33--

COCO332-2-

Minor contributors: Minor contributors: OHOH--, NH, NH3 3

Phosphates, Silicates, Borates Phosphates, Silicates, Borates

AlkalinityAlkalinity: Concentration of soluble alkali : Concentration of soluble alkali with capacity to neutralize acids with capacity to neutralize acids

pH increasepH increase Micronutrients solubility decreaseMicronutrients solubility decrease

Alkalinity-induced Alkalinity-induced Fe DeficiencyFe Deficiency

Whipker et al., 2001

Impossible to Study Impossible to Study HCOHCO33

-- Alone Alone

HCOHCO33--

Na+ Ca++

K+

Li+

Rb+

Mg++

NH4+

Cs+

Mixture ExperimentsMixture Experiments 2 or more 2 or more Components Components are mixedare mixed

RbRb+++ K+ K++ + Na + Na++

The total concentration is held fixedThe total concentration is held fixed RbRb+++ K+ K++ + Na + Na++= 7.5 m= 7.5 mMM

MixtureMixture: resulting of mixing components at different : resulting of mixing components at different proportionsproportionsRbRb++ : K : K++ : Na : Na++

1/3 : 1/3 : 1/31/3 : 1/3 : 1/3

Mixture Amount ExperimentMixture Amount Experiment:: RbRb+++ K+ K+++ Na+ Na++=7.5 m=7.5 mMM RbRb+++ K+ K+++ Na+ Na++=2.5 m=2.5 mMM

½:½:0

0:½:½

2/3:1/6:1/6

1/6:2/3:1/6 1/6:1/6:2/3

1/3:1/3:1/3

Pure blend

s

Tertiary blends

Binary blends

Rb+

1:0:0

K+

0:1:0Na+

0:0:1

Rb+ K+ Na+ 1 : 0 : 0

½:0:½

ObjectivesObjectives

Determine the Determine the effect of some effect of some counter-cations of HCOcounter-cations of HCO33

-- on the on the response of bean plants to response of bean plants to HCOHCO33

- -

Separate the effectSeparate the effect of the of the counter-cation from the effect counter-cation from the effect of HCOof HCO33

- -

Materials and MethodsMaterials and Methods

Phaseolus vulgarisPhaseolus vulgaris ‘Poncho’‘Poncho’

Seeds germinated at 28Seeds germinated at 2800CC HydroponicsHydroponics

– 7 days establishing period7 days establishing period– 21 day under treatment21 day under treatment

Mixture-Amount ExperimentMixture-Amount Experiment

Effect of Mixtures of Effect of Mixtures of RbRb++, K, K++, and Na, and Na++, on , on

the Response of Bean the Response of Bean Plants to HCOPlants to HCO33

--

K+

0 : 7.5 : 0

Rb+

7.5 : 0 : 0

Na+

0 : 0 : 7.5

3.75 : 3.75 : 0

0 : 3.75 : 3.75

5 : 1.25 : 1.25

1.25 : 5 :

1.25

1.25 : 1.25 : 5

2.5 : 2.5 : 2.5

3.75 : 0 : 3.75

0 HCO3-

Total Concentration = 7.5 mM

K+

0 : 7.5 : 0

Rb+

7.5 : 0 : 0

Na+

0 : 0 : 7.5

3.75 : 3.75 : 0

0 : 3.75 : 3.75

5 : 1.25 : 1.25

1.25 : 5 : 1.25

1.25 : 1.25 : 5

2.5 : 2.5 : 2.5

3.75 : 0 : 3.75

7.5 HCO3

-

Na+

0 HCO0 HCO33--

K+

Rb+

Na+

7.5 HCO7.5 HCO33--

K+

Rb+

Rb+7.5mM

K+ 0 mM

Na+7.5mM Na+ 0 mM

2.5

3.5

4.5

5.5

Rb+ 0 mM

K+ 7.5mM

Shoot Dry MassShoot Dry Mass

O HCO3 -

7.5 HCO3-

Sh

oot

Dry

M

ass (

g)

Rb+7.5mM

K+ 0 mM

Na+7.5mM Na+ 0 mM

2.5

3.5

4.5

5.5

Rb+ 0 mM

K+ 7.5mM

Shoot Dry MassShoot Dry Mass

Na+ tox./K+ def.=-19%

HCO3- effect=-15%

Sh

oot

Dry

M

ass (

g)

Rb+7.5mM

K+ 0 mM

Na+7.5mM Na+ 0 mM

2.5

3.5

4.5

5.5

Rb+ 0 mM

K+ 7.5mM

Shoot Dry Mass Shoot Dry Mass

Rb+ tox./K+ def.=-30%

HCO3-effect=-18%

Sh

oot

Dry

M

ass (

g)

LEAF TISSUE KLEAF TISSUE K++

%%

0.93

1.01

0m0mMM HCO HCO33--

3.16

1.37

2.00

Rb+

Na+K+

Rb+7.5mM

K+ 0 mM

Na+7.5mM Na+ 0 mM

2.5

3.5

4.5

5.5

Rb+ 0 mM

K+ 7.5mM

Shoot Dry Mass Shoot Dry Mass

Rb++Na+ toxicity=-16%

HCO3-=-22%

Sh

oot

Dry

M

ass (

g)

Effect of Binary Effect of Binary Mixtures of KMixtures of K+ + and and

NaNa++ on the Response on the Response of Bean Plants to of Bean Plants to

HCOHCO33--

Mixture-Amount Binary Mixture-Amount Binary ExperimentExperiment

K+

2.5 : 0

Na+

0 : 2.5K+ Na+

1.25 : 1.25K+ Na+

1.88 : 0.62K+ Na+

0.62 : 1.88K+

2.5 : 0

K+ Na+

1.88 : 0.62K+ Na+

1.25 : 1.25K+ Na+

0.62 : 1.88Na+

0 : 2.5

2.5 HCO2.5 HCO33--

0 HCO0 HCO33--

K+

5 : 0

Na+

0 : 5K+ Na+

2.5 : 2.5K+ Na+

3.75 : 1.25K+ Na+

1.25 : 3.75K+

5 : 0

K+ Na+

3.75 : 1.25K+ Na+

2.5 : 2.5K+ Na+

1.25 : 3.75Na+

0 : 5

5 HCO5 HCO33--

0 HCO0 HCO33--

K+

7.5 : 0

Na+

0 : 7.5K+ Na+

3.75 : 3.75K+ Na+

3.75 : 3.75K+ Na+

3.75 : 3.75K+

7.5 : 0

K+ Na+

3.75 : 3.75K+ Na+

3.75 : 3.75K+ Na+

3.75 : 3.75Na+

0 : 7.5

7.5 HCO7.5 HCO33--

0 HCO0 HCO33--

0m0mMM

HCOHCO33--

2.5m2.5mMM

HCOHCO33--

K+:Na+ 1:0 0.75:0.25 0.5:0.5 0.25:0.75 0:1 4.37g 4.75g 4.73g 3.63g 2.36g

3.02g 3.30g 3.43g 3.01g 2.12g

1.00

2.00

3.00

4.00

5.00

6.00

0.00 1.00

0.25 0.75

0.50 0.50

0.75 0.25

1.00 0.00

2.5 HCO3-

2.5 m2.5 mMM total total mixturemixture

0 HCO3-

Proportion of K+ and Na+

Shoot Dry MassShoot Dry Mass

Na+=-19%

HCO3-=-19%

Sh

oot

Dry

M

ass (

g)

Na+

K+

K+:Na+ 1:0 0.75:0.25 0.5:0.5 0.25:0.75 0:1

0m0mMM

HCOHCO33--

5m5mMM

HCOHCO33--

4.93g 4.15g 4.86g 4.29g 2.45g

2.79g 2.87g 3.34g 2.55g 1.62g

0.00 1.00

0.25 0.75

0.50 0.50

0.75 0.25

1.00 0.00

5 m5 mMM total total mixturemixture

0 HCO3-

5 HCO3-

Proportion of K+ and Na+

Shoot Dry Mass Shoot Dry Mass

Na+=-17%

HCO3-=-24%

Sh

oot

Dry

M

ass (

g)

1.0

2.0

3.0

4.0

5.0

6.0

Na+

K+

0m0mMM

HCOHCO33--

7.5m7.5mMM

HCOHCO33--

K+:Na+ 1:0 0.75:0.25 0.5:0.5 0.25:0.75 0:1 5.18g 4.31g 4.58g 2.45g3.15g

2.59g 2.86g 2.20g 2.78g 2.15g

0.00 1.00

0.25 0.75

0.50 0.50

0.75 0.25

1.00 0.00

7.5 mM total mixture

0 HCO3-

7.5HCO3-

Proportion of K+ and Na+

Shoot Dry Mass Shoot Dry Mass

Na+=-41%

HCO3-=-15%

Sh

oot

Dry

M

ass (

g)

Na+

K+

6.0

5.0

4.0

3.0

2.0

1.0

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

10 11 12 13 14 15 16 17 18 1 2 3

Na+ (mM)2.5 2.5 5.0 5.0 7.5 7.5 7.5 7.5 1.88 3.75 5.6

HCO3- (mM)

Bicarbonate Effect Sodium Effect

Percentage Growth Reduction due to Percentage Growth Reduction due to Counter-Cation and HCOCounter-Cation and HCO33

--

Average=18%

% S

hoo

t D

ry M

ass

Dec

reas

e

ConclusionsConclusions

The effect of both NaThe effect of both Na++ and HCO and HCO33-- is is

approximately the same at normal approximately the same at normal concentrationsconcentrations

At high concentrations, the NaAt high concentrations, the Na++ toxicity effect is much higher than toxicity effect is much higher than that of HCOthat of HCO33

--