Root Growth & Function The Origin of All that is Green · ROOT GROWTH & FUNCTION--The Origin of All that is Green--Carolyn Scagel USDA-ARS-Horticultural Crops Research Lab. ... Nutrient

ROOT GROWTH & FUNCTIONROOT GROWTH & FUNCTION----The Origin of All that is GreenThe Origin of All that is Green----

Carolyn ScagelCarolyn ScagelUSDAUSDA--ARSARS--Horticultural Crops Research LabHorticultural Crops Research Lab

NURSERY RESEARCH PRIORITIESNURSERY RESEARCH PRIORITIES

• Propagation– Cuttings– Tissue Culture– Labor– Turnover

• Nutrition– Uptake– Efficiency– Timing

• Rhizosphere Organisms

• Pathogen/Pests

• Media– Formulations– Amendments

• Containers– Size,Configuration– Labor

• Hardiness

• Weed Control

ROOT PHYSIOLOGY RESEARCHROOT PHYSIOLOGY RESEARCH

• Nutrition– Uptake– Efficiency– Timing

• Propagation– Cuttings– Tissue Culture

• RhizosphereOrganisms

Plant Nutrition&

Growth

MycorrhizalFungi

Root Growth&

Function

Physiological aspects of root development, & Physiological aspects of root development, & function influencing crop productivity and quality.function influencing crop productivity and quality.

CROP FOCUSCROP FOCUS• Woody Perennials

– Largest portion of PNW nursery crops.– Underlying mechanisms for understanding woody plant

metabolism requires long-term research.

• Ericaceae– Cross over between nursery and small fruit production.– Special nutritional requirements.

• Geophyte Floral Crops– Grown for cut flower and vegetative production in PNW.– Optimal requirements of production dependant on

patterns of nutrient and carbon partitioning.

RESEARCH GOAL #1RESEARCH GOAL #1

-Reduce inputs-Reduce nutrient runoff-Increase nutrient use efficiency-Increase water use efficiency

Help develop cost effective and environmentally sustainable production practices

Nutrient ManagementNutrient Management• Importance:

– Optimal rates, timing of application, and formulations used are not well established.

– Links between nutritional status and stock quality are poorly defined.

RESEARCH GOAL #2RESEARCH GOAL #2Improve production efficiency and end product quality

-Decrease labor-Reduce time to market-Improve quality

Regulation of Root GrowthRegulation of Root Growth• Importance:

– Root formation is the rate limiting step in production of cuttings and tissue culture plants

– Amount, type, and form of roots correlated with stock quality and plant survival after transplanting

Mycorrhizal FungiMycorrhizal Fungi• Importance:

– Optimal uses of fungi duringcommercial nursery production

– Commercialization withoutapplication criteria inhorticultural systems.

– Variable understandingof expected results.

NUTRIENT MANAGEMENTNUTRIENT MANAGEMENT• Program Scope:

– Environment/culture– Formulations– Application methods– Timing– Plant type– Mycorrhizal Fungi

• Assessments:– Plant, soil, and water

nutrient analyses– 15N-compounds– Plant growth– Storage reserves– Transplant quality

NUTRIENT MANAGMENTNUTRIENT MANAGMENT–– Timing of Fertilizer Applications Timing of Fertilizer Applications ––

Highest uptake efficiency occurs when fertilizer availability isHighest uptake efficiency occurs when fertilizer availability issynchronized with plant uptakesynchronized with plant uptake

(With Oregon State and Mississippi State University)(With Oregon State and Mississippi State University) Bi et al. 2006

Date05/31 06/14 06/28 07/12 07/26 08/09 08/23 09/06

N U

ptak

e R

ate

(mg

d-1)

-2

0

2

4

6

8

Rhododendron 'PJM H-1'Rhododendron 'Cannon's Double'

A. Total Plant N Uptake Rate

Date05/31 06/14 06/28 07/12 07/26 08/09 08/23 09/06

N U

ptak

e Ef

ficie

ncy

(% F

ertil

izer

App

lied)0

10

20

30

40

Rhododendron 'PJM H-1'Rhododendron 'Cannon's Double'

B. N Uptake Efficiency

NUTRIENT MANAGMENT NUTRIENT MANAGMENT –– Timing of Fertilizer Applications Timing of Fertilizer Applications ––

Uptake can occur in the autumn.Uptake can occur in the autumn.Root and leaf losses decrease uptake efficiencyRoot and leaf losses decrease uptake efficiency


Time (Month)May Jun Jul Aug Sep Oct Nov Dec Jan Feb

N U

ptak

e R

ate

(mg

d-1)

-2

0

2

4

6

8

10

Rhododendron 'P.J.M. Compact'Rhododendron 'English Roseum'Rhododendron 'Gibraltar'

A. Total Plant Uptake Rate

Time (Month)

Jun Jul Aug Sep Oct Nov Dec Jan Feb

N U

ptak

e Ef

ficie

ncy

from

Fer

tiliz

er (%

)

0

10

20

30

40

50

60

70

Rhododendron 'P.J.M. Compact'Rhododendron 'English Roseum'Rhododendron 'Gibraltar'

B. Uptake Efficiency from Fertilizer

NUTRIENT MANAGMENT NUTRIENT MANAGMENT –– Fertilizer Application Methods Fertilizer Application Methods ––

Foliar Urea improved growth and efficiency of fertilizer useFoliar Urea improved growth and efficiency of fertilizer use


Autumn Foliar TreatmentNo Urea 3% Urea

Tota

l Pla

nt N

itrog

en C

onte

nt (m

g)

0

100

200

300

400

500 Rhododendron 'P.J.M. H-1'Rhododendron 'Cannon's Double'

aa

b

b

Autumn Foliar TreatmentNo Urea 3% Urea

Tota

l Pla

nt B

iom

ass

(g)

0

20

40

60

80No Spring NSpring N

Winter 2004

a

b

cc

Spring 2005

NUTRIENT MANAGMENT NUTRIENT MANAGMENT –– Fertilizer Application Methods Fertilizer Application Methods ––

Foliar urea improved growth and flowering.Foliar urea improved growth and flowering.Foliar urea decreased dependence on N in spring. Foliar urea decreased dependence on N in spring.

(Mississippi State University)(Mississippi State University)

No Urea in Autumn Foliar Urea Autumn

Bi 2006

No Spring N No Spring N Spring NSpring N

Hydrangea

NUTRIENT MANAGMENT NUTRIENT MANAGMENT –– Integrated Nutrient Management Integrated Nutrient Management ––

Using foliar urea with defoliant improves performanceUsing foliar urea with defoliant improves performance

(With Oregon State and Mississippi State University)(With Oregon State and Mississippi State University)

Defoliant in Autumn Urea & Defoliant in Autumn

Bi et al. 2005

P K SN CA MG

Relative Aboveground Weight (Peat=100)

0 200 400 600 800 1000 1200

Rel

ativ

e N

utrie

nt C

once

ntra

tion

(Pea

t=10

0)

0

50

100

150

200

250

300

350

400

'Freckles''Olympic Fire''Pink Charm'

Kalmia latifolia

NUTRIENT MANAGMENT NUTRIENT MANAGMENT –– Media Composition Media Composition ––

Kalmia latifolia

Bark/PerlitePeat

Bark/PerliteCoir

Bark/PerlitePeat/Coir

Coir can be use to improve Coir can be use to improve growth and enhance uptake of N, growth and enhance uptake of N,

P, and KP, and K

Scagel 2003

I

II

III

Enhanced Uptake

Non-limiting

NUTRIENT MANAGEMENTNUTRIENT MANAGEMENT–– Mycorrhizal Fungi & Fertilizer Type Mycorrhizal Fungi & Fertilizer Type ––

Mycorrhizae decreased conductivity of Mycorrhizae decreased conductivity of leachateleachate

Time After Planting (days)10 20 30 40 50 60 70 80 90

Con

duct

ivity

(mS)

0

100

200

300

400

500

600None, Inorganic FertilizerMYC, Inorganic FertilizerNone, Organic FertilizerMYC, Organic Fertilizer

Scagel 2006

Vaccinium ovatum

REGULATION OF ROOT GROWTHREGULATION OF ROOT GROWTH• Program Scope:

– N & C metabolism• Storage reserves• Stock plant nutrition

– Hormones• IAA• Ethylene• Polyamines

– Mycorrhizal Fungi• AMF• Ericoid• Ecto• Arbutoid

• Assessments:– Hormone analysis– Nutrition & composition– Rooting/survival– Gene regulation

REGULATION OF ROOT GROWTH REGULATION OF ROOT GROWTH –– Plant Composition Plant Composition ––

Optimal levels of stem N for rootingOptimal levels of stem N for rootingScagel 2001

Stem Nitrogen (mg/g)

0 20 40 60 80 100 120 140

Roo

ting

(% o

f cut

tings

with

root

s)

0

20

40

60

80

100

120

Pink CharmOlympic FireFreckles

Kalmia latifolia


Form of N (protein) may be equally important to rootingForm of N (protein) may be equally important to rootingScagel 2001

Stem Protein (μg/g)

0 100 200 300

Roo

ting

(% o

f cut

tings

with

root

s)

0

20

40

60

80

100

120

Pink CharmOlympic FireFreckles

Kalmia latifolia

10 20 30 40 50 60 70 80 90 100


Optimal rooting as a function of N form and N levelOptimal rooting as a function of N form and N level

Kalmia latifolia

Nitrogen (m

g/g)Protein(ug/g)

Rooting (

%)

Scagel 2001

REGULATION OF ROOT GROWTHREGULATION OF ROOT GROWTH–– Media Composition Media Composition ––

Media composition effects on N content can alter rootingMedia composition effects on N content can alter rootingScagel 2002

Cultivar

Pink Charm Olympic Fire Freckles

Nitr

ogen

Con

cent

ratio

n (m

g g-1

)

0

20

40

60

80

100

120Peat Peat/Coir Coir

Kalmia latifolia

~80 ~95

~70

REGULATION OF ROOT GROWTHREGULATION OF ROOT GROWTH–– Media Composition Media Composition ––

Media composition effects on protein content can alter rootingMedia composition effects on protein content can alter rootingScagel 2002

Cultivar

Pink Charm Olympic Fire Freckles

Prot

ein

Con

cent

ratio

n ( μ

g g-1

)

0

100

200

300

400Peat Peat/Coir Coir

Kalmia latifolia

~230

~300

~150

REGULATION OF ROOT GROWTH REGULATION OF ROOT GROWTH –– Mycorrhizal Fungi in Propagation Mycorrhizal Fungi in Propagation ––

Increased adventitious roots on cutting using mycorrhizal fungiIncreased adventitious roots on cutting using mycorrhizal fungi

Non-Inoculated Inoculated

Arctostaphylos uva-ursi

Linderman & Call 1977

REGULATION OF ROOT GROWTHREGULATION OF ROOT GROWTH––Mycorrhizal Fungi in Propagation Mycorrhizal Fungi in Propagation ––

Adding fungi to the rooting medium can achieve a rooting responsAdding fungi to the rooting medium can achieve a rooting responseethat is equal to or better than the response obtained by using rthat is equal to or better than the response obtained by using rootingooting

hormones alone.hormones alone.Scagel 2004

Percent Rooting (% of cuttings)

20 40 60 80 100 120

Roo

t Len

gth

(cm

)

0

100

200

300

400

500

No Hormone, No Mycorrhizal FungiHormone (IBA)Oidiodendron griseum (OG)IBA+OGHymenosphyus ericae (HE)IBA+HE

Leucothoe 'Rainbow'

REGULATION OF ROOT GROWTHREGULATION OF ROOT GROWTH–– Mycorrhizal Fungi in Propagation Mycorrhizal Fungi in Propagation ––

AMF induced changes in rooting may involve differentAMF induced changes in rooting may involve differentregulatory mechanisms than those involved primarily with auxin regulatory mechanisms than those involved primarily with auxin

responseresponseScagel 2004

Time After Sticking (Days)

0 2 4 6 8 10 12 14 16

Stem

Pro

tein

( μg

g-1)

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

No IBA, No AMFHormone (IBA)Mycorrhizal Fungi (AMF)IBA+AMF

Miniature Rose 'Scarlet Cupido'

GC-MSHPLC

Hormonal signals during root induction by mycorrhizal fungiHormonal signals during root induction by mycorrhizal fungi(With University of Helsinki)(With University of Helsinki)

REGULATION OF ROOT GROWTHREGULATION OF ROOT GROWTH–– Mycorrhizal Fungi & Stock Quality Mycorrhizal Fungi & Stock Quality ––

From Scagel, 1999Improved root growth after transplantingImproved root growth after transplanting

Scagel 2001

Time After Planting

Spring Year 1 Autumn Year 1 Autumn Year 2

Roo

t Gro

wth

(g)

0

50

100

150

200

250

Control IBAMycorrhizal FungiHormone & Mycorrhizal Fungi

Pseudotsuga menzesii

REGULATION OF ROOT GROWTHREGULATION OF ROOT GROWTH–– Mycorrhizal Fungi & Stock Quality Mycorrhizal Fungi & Stock Quality ––

From Scagel, 1999Improved survival after transplantingImproved survival after transplanting

Scagel 2001

Time After Planting

Spring Year 1 Autumn Year 1 Autumn Year 2

Surv

ival

(%)

0

20

40

60

80

100

120

Control IBAMycorrhizal FungiHormone & Mycorrhizal Fungi

Pseudotsuga menzesii

MYCORRHIZAL FUNGIMYCORRHIZAL FUNGI• Program Scope:

– Fertilizer use– Hormones and rooting– N & C metabolism

• Assessments– Surveys & inoculation

trials– Plant & soil analyses– Growth/partitioning– Colonization– Bulb & Flower

Production

MYCORRHIZAL FUNGI MYCORRHIZAL FUNGI –– Responsiveness to Inoculation Responsiveness to Inoculation ––

Selection during breeding can decrease responsiveness to Selection during breeding can decrease responsiveness to mycorrhizaemycorrhizae

BC (>3gen) EB (>2gen) PA (>2gen) GG (>1gen)

Bio

mas

s (g

)

0

20

40

60

80

100


Scagel 2005

Vaccinium spp.

MYCORRHIZAL FUNGI MYCORRHIZAL FUNGI –– Who’s On Your Roots Who’s On Your Roots ––

Using a combination of techniques to Using a combination of techniques to identify and evaluate function of identify and evaluate function of

ericoid mycorrhizal fungi in different ericoid mycorrhizal fungi in different production systemsproduction systems

(With University of Melbourne and Wisconsin)(With University of Melbourne and Wisconsin)

MYCORRHIZAL FUNGIMYCORRHIZAL FUNGI–– AMF & Production Time AMF & Production Time ––

Inoculation decreases time of stem emergenceInoculation decreases time of stem emergence

No Soil Treatment Soil Pasteurization

Stem

Em

erge

nce

Afte

r Pla

ntin

g (d

ays)

0

20

40

60

80


Scagel 2004

MYCORRHIZAL FUNGI MYCORRHIZAL FUNGI –– AMF & Production Time AMF & Production Time ––

Inoculation decreases time of flower emergenceInoculation decreases time of flower emergence

No Soil Treatment Soil Pasteurization

Flow

er E

mer

genc

e Af

ter P

lant

ing

(day

s)

0

20

40

60

80

100

120


Scagel 2003

MYCORRHIZAL FUNGI MYCORRHIZAL FUNGI –– AMF & Quality AMF & Quality ––

Inoculation increases flower productionInoculation increases flower production

Date6/5 6/19 7/3 7/17 7/31 8/14 8/28

Num

ber o

f Flo

wer

s (#

)

0

5

10

15

20

25

30None, Non-sterile soilAMF, Non-sterile soilNone, Sterile soilAMF, Sterile soil

Scagel 2004

COOPERATORSCOOPERATORS• Oregon State

– Les Fuchigami– Rich Regan

• Agriculture Canada– Shufu Dong

• Mississippi State University– Guihong Bi

• Cornell University– Lailang Cheng

• Ohio State– Hannah Mathers

• University of Wisconsin– Kevin Kosola

• University of Helsinki– Karoliina Niemi

• University of Melbourne– Cas McLean

• Meadow Lake Nursery• Fisher Farms• Fall Creek Farm & Nursery• Monrovia• Briggs Nursery• Brush Prairie Bogs• Winsmuir Farm• ZCallas

Symptoms of poor root health occur above ground before you realize roots are in trouble

and mimic symptoms of other problems.

Documents

Root Growth & Function The Origin of All that is Green · ROOT GROWTH & FUNCTION--The Origin of All that is Green--Carolyn Scagel USDA-ARS-Horticultural Crops Research Lab. ... Nutrient