Demography and population dynamics of ectomycorrhizas of sitka spruce fertilized with N

49~

Agriculture,

Ecosystems

and Environment,

28

(1989)

493-496

Elsevier Science Publishers B.V., Amsterdam Printed in C z e c h o s l o v a k i a

DEMOGRAPHY AND POPULATION DYNAMICS SITKA SPRUCE FERTILIZED WITH N TAYLOR,

A.F.S.

AND ALEXANDER,

OF

determined 8xamined. forming was

University

16 m y c o r r h i z a l

period.

32,000

root tips were

types were

found,

with

n e a r l y 70% of the tips examined. with

Ordination matter

94%

of

analysis

the

tips

of the data

accumulation

important

of Aberdeen,

of a 43 year old S i t k a spruce stand was

over a two year

high,

OF

I.J.

D e p a r t m e n t of Plant and Soil Science, A b e r d e e n , AB9 2UE, S c o t l a n d

Root tip d e m o g r a p h y

ECTOMYCORRHIZAS

and

in d e t e r m i n i n g

Level of infection being

mycorrhizal.

indicates

moisture mycorrhizal

one type

that

organic

availability

may

be

population

structure.

INTRODUCTION Population

studies

of e c t o m y c o r r h i z a s

state are rare. A few infection present. fine

and

the

compartment

this s t u d y we

a two year period,

Cores

the level of

of the e c t o m y c o r r h i z a l

examined

the

demography

the fine root p o p u l a t i o n

(Picea s i t c h e m s i m from April

(Bong.)

1983 to April

Carr.)

types of the

time.

In

structure stand over

1985.

AND METHODS

were

horizons

considered

over an e x t e n d e d p e r i o d of

determined

of a S i t k a S p r u c e

have

proportions

None have however

root

N~I~RI~[.S

studies

b a s e d on the v e g e t a t i v e

of

taken a

for 24

replicated

consecutive randomised

year old S i t k a S p r u c e c o n s i s t i n g

of

months

from

the

block experiment control,

LFH in 37

N-treated

and

494

C-treated

plots.

Fine

e x c i s e d and counted. embedded

and

tips

identified

A c.i0%

semi-thin

16 m y c o r r h i z a l 32,000

roots were

and

4

were

subsample

transverse

scanned.

isolates

A

and all live tips

of the tips was resin

sections

non-mycorrhizal

from pure c u l t u r e

and c a r p o p h o r e

extracted

root

number

syntheses

used to c l a s s i f y tip types.

of

the

types

Some were

c a r r i e d out u s i n g root

from the site or

by reference

to the

literature.

DISCUSSION

The level of i n f e c t i o n was mycorrhizal. treatment. eystem,

This One

was

w i t h n e a r l y 70%

of

(Fig.

than 55% of the sample. relative

passage

of

season

analysis

using

detrended

the

DECORANA,

of Hill and

scores

from D E C O R A N A

study

period,

accumulation

I).

the

No

other

appeared

Gauch

(1980).

for each plot

be the

number

r e l a t e d to the forest

floor.

data was c a r r i e d out analysis

Fig.

2 shows

the extent of

horizons

programme, the Axis

organic

in that plot.

type

related

spatial

absolute

more

1

in the first m o n t h of the

that the r e l a t i v e p r o p o r t i o n to

to

the p o p u l a t i o n

the root

type over time were

through

indicates is

the n i t r o g e n

apparently being

in the

correspondence

LFH

by

type c o m p r i s e d

of the d o m i n a n t

plotted against

in

c.80%

type c l e a r l y d o m i n a t e d

fronts of

of the root tips were

the m y c o r r h i z a s

but

wetting

Ordination

to

Fluctuations

proportion

not r e l a t e d to

94%

reduced

mycorrhizal

formed b y one fungus

and

high,

of

variation

each in

This

matter result

mycorrhizal

organic matter

495

MEAN PERCENT OF l i p TYPES IN THE LFH OF THE CONTROL PtOT$ ESTIMATED FROM 24 MONTHLY SAMPLES 70

60

SO

JO

TO g-

2

Figure

3

,

5

6

7

s

i. T H E M E A N P E R C E N T A G E

HORIZONS

OF

SAMPLES.

TYPE

THE

CONTROL

9

OF

'~,

ROOT

PLOTS,

3 IS T H E A M A L G A M A T E D AXIS ! S C O R E S

lo

~

~

,,-17

TIP TYPES

ESTIMATED

IN THE LFH

FROM

24 M O N T H L Y

NON-MYCORRHIZAL

TYPES.

V E R S U S D E P T H OF LFH

APRIL t g 8 3

;o

N

S

S

C

10-

C C N

-10,

S

"20-

-30

-40 2TO

3'o

.¢o

so

so ODM • 10' kg h~'

N-NITROGEN S-CAReO N C-CONTROL

Figure

2.

ESTIMATED PLOTS

IN

RELATIONSHIP WEIGHT

APRIL

OF 1983.

BETWEEN

ORGANIC C

MATTER - CONTROL

AXIS

1

I~: T H E

LFH

S

sCORES

AND

HORIZONS

- CARBON

N

-

OF

THE THE

NITROGEN

496

accumulation.

The

same relationship

also holds

for moisture

availability. The

nitrogen

proportions the

of

the

affected

types,

of

fruitbodies

population

most abundantly,

type. study

is

structure.

the

particularly

dominant

on the site over the

occurence

mycorrhizal

also

of mycorrhizal

proportion

carpophores the

treatment

A

by reducing

survey

period,

not

relative

of

the

showed that

a good indicator of

Those species which

each formed less than 5%

fruited

of the mycorrhizal

types examined.

REFERENCE

Hill

M.O.

analysis:

&

Gauch

an improved

H.G.,

1980.

ordination

Detrended technique.

correspondence Wegetatio

42:

47-58.

Taylor, A.F.S. and Alexander, I.J.# 1989: Demography and population dynamics of ectomycorrhizas of Sitka spruce fertilized with N. Agric.,

Ecosystems

Environ.,

28: 493-496.