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MPN estimates of VAM diaspores in cultivated soils
199
Agriculture, Ecosystems and E n v i r o n m e n t , 29 (1989) E l s e v i e r S c i e n c e P u b l i s h e r s B . V . , Amsterdam Printed i n Czechoslovakia
MPN e s t i m a t e s
I.
o£ VAM d i a s p o r e s in c u l t i v a t e d
Jekobsen and T. Heidmann, A g r i c u l t u r a l
Rise N a t i o n a l
Laboratory,
199-203
soils
Research O e p a r t m e n t ,
0K-4000 R o s k i l d e and Research C e n t r e
Foulum, DK-8833 Orum S e n d e r l y n g ,
Denmark
ABSTRACT Most NPN e s t i m a t e s locations
samples from t h r e e
were i n t h e r a n g e 20-450 d i a s p o r e s
considerable limited
o f VAM d i a s p o r e s i n s o i l
variation
extent
within
be e x p l a i n e d
each l o c a t i o n by o t h e r s o i l
(100 9 s o i l ) "1
A
could only to a p a r a m e t e r s and
cropping history. INTRODUCTION The r a t e
of establishment
is influenced in the soil. bility
o f VA m y c o r r h i z a
by t h e number o f i n f e c t i v e More i n f o r m a t i o n
(VAH) i n a n n u a l crops
propagules
(diasporas)
i s needed on t h e v a r i a t i o n
o f d i a s p o r a numbers. The o b j e c t i v e
o f t h e p r e s e n t work was
t o d e t e r m i n e numbers n f VAN d i a s p o r a s a t w e l l - d e f i n e d points
in three
ent farming
fields,
sampling
where l o n g - t e r m e x p e r i m e n t s w i t h
systems have r e c e n t l y
and s t a -
differ-
been i n i t i a t e d .
MATERZALS ANO METHODS Ten s o i l
samples were c o l l e c t e d
locations
(Table 1).
i n t h e autumn from each o f t h r e e
O n l y b a r l e y o r wheat had been grown a t Odum
during the previous three
years,
while different
had been p l a c e d a t Jyndevad end Foulum u n t i l fore
sampling,
subsamples
when b a r l e y
crop r o t a t i o n s
the last
spring
was sown. Each sample c o n s i s t e d
be-
o f 12
($ 55 mm, 0 - 2 0 cm depth) t a k e n from an area o f 28 m2
200
around a defined p o i n t . with irradiated
S o i l was sieved (< 4 mm) and d i l u t e d
(10 kGy) s o i l
of the same sample. O i l u t i o n s were
eithe~ 2 - f o l d w i t h seven r e p l i c a t e
p l a n t s at each of s i x steps
(J) or l O - f o l d w i t h ten r e p l i c a t e s st each. of f i v e E). Cucumber p l s n t s were grown i n 60 g s o i l
lots
steps (F and
i n t r a y s placed
i n the greenhouse f o r 26 (J) or 28 (F and ~ ) . d a y s .
NPN e s t i m a t e s
were obtained from the number of i n f e c t e d p l a n t s as described by F i s h e r and Ystee (1963). Levels of YAH i n f e c t i o n i n p l a n t s from u n d i l u t e d s o i l
after
were recorded
11 end 26 d , y s
(J) or 28
days (F and E). Results were compared w i t h • wide range of p h y s i o - c h e m i c e l and b i o l o g i c s 1 parameters also measured at the 30 sampling p o i n t s .
Tab. 1. Some c h a r a c t e r i s t i c s
Location
F i e l d area
of the t h r e e sampling s i t e s
Soil type
(he)
pH
01sen P
(10"2M CeCl2)
(mg kg "1)
Jyndevsd (J)
18
coarse sand
5.2-6.2
37-55
Foulum (F)
25
loamy send
5.4-5.9
33-42
Bdum (B)
16
sandy loam
6.1-6.6
22-38
RESULTS The number of VAH diasporas v a r i e d c o n s i d e r a b l y between samples w i t h i n each l o c a t i o n
and i n s p i t e of the wide confidence i n t e r -
v a l of the s i n g l e estimates s i g n i f i c a n t ell
locations
(Fig.
cropping h i s t o r y
differences
appeared s t
1). Oisspore numbers c o r r e l a t e d
poorly with
end s o i l
v ~ r i e b l e e except at Jyndevsd where
201
significant ~0.76)
correlations
were o b s e r v e d .
from u n d i l u t e d tions
(Fig.
2).
ni£ican¢ly
late
In£ection
levels
plants
more c l o s e l y
not c l o s e l y
within
correlated
from u n s t e r i l e
with
than b~tween l o c a -
(r = 0.74,
Znfection
levels
Jyndevad s o i l
0.73,
and
measured
d i d nor c o r r e -
d i s s p o r e numbers.
JYNDEVAD 400
i n cucumber r o o t s
end d i a s p o r e numbers were s i g -
F, and ~, r e s p e c t i v e l y ) ;
22-day-old
and Olsen P ( r =
Levels of VAN i n f e c t i o n
were l e s s v a r i a b l e
although
0.78 £or J, in
soil
w i t h pH ( r = 0.74)
ODUM
1200
= 18o I
I
C,V =
11 ~.
T
1000
"~ 200
v)
BOO "0 0
o
0 0 q.,
0
~. f/J
600
FOULUM
P 400
o
=
0 n_
205
0
GV = 44
400
0
:E ~00 200
1 2
3
4
5
6
7
8
910
1 2 3 4 5 6 7 8 9 1 0
Somple No.
Somple No, 95~, confidence Intervols:
Fig.
JYNt)EVAD
0.59 MPN -
FOU~UM ~ ) ~DUM
0.4.3 MPN - 2.32 MPN
2. Number of VAH d i a s p o r e s
and Foulum.
1.69 MPN
i n samples from Jyndevad,
Odum,
202
40 JYNDEVAD X ' = 20 CV = 32 20
Hlii
0
m
rOU
_
40
}
•
o
~ 2o
-
I
c
X
0
-
'
ODUM
20
X=12 CV = 47
0 1
2 3 4 5 6 7 6 3 1 0
1
Sample No.
Fig.
2. Levels of VAM i n f e c t i o n
in 26-
(J) or 28- (F and 0) day
old cucumber plants grown in undiluted soil.
Z03
DISCUSSION Numbers o f VAN d i a s p o r a s i n t h e p r e s e n t work are i n t h e same r a n g e as found i n c u l t i v a t e d 1983).
soils
A l t h o u g h some v a r i a t i o n
i n U.K.
(Sanders and Sheikh
s t Jyndevad c o u l d be e x p l a i n e d by
s o ~ l P and pH t h e background f o r t h e o b s e r v e d v a r i a t i o n s largely
unexp!a'ined.
be t e s t e d
by f u t u r e
defined.points.. levels
HPN t e s t s
counts lay
shown t o
The p o s s i b l e populations future
of the single
estimates
between d i s s p o r e numbers and
were n o t c l o s e ,
possibly
above 50-100 (100 g s o i l ) " 1 ,
'saturate'
i,lportance
will
on ssmples from t h e same w e l l -
The r e l a t i o n s h i p s
of V A N . i n f e c t i o n
dias~ore ously
The s t a b i l i t y
remains
the roots
s range previ-
(Sanders and S h e i k h 1983).
of qualitative
is being investigated
because most
differences
end w i l l
i n t h e fungml
be c o n s i d e r e d a l s o i n
samplings.
REFERENCES FISHER, R . A . , cultural
YATES, F. S t a t i s t i C a l
and m e d i c a l r e s e a r c h .
SANOERS, F . E . , lsr
mycorrhizal
71:
223-246,
- Oliver
for
biological,
agri-
and Boyd, E d i n b u r g h ,
1963.
SHEIKH, N.A. The d e v e l o p m e n t o f v e s i c u i a r - a r b u s c u infection
in plant
root
systems.
- Plant
and S o i l
1983.
Jakobsen, I. and Heldmann, T., dlaspores in cultivated soils. 29:
tables
199-203~
1989: Agric.
MPN e s t i m a t e s o f VAM Ecosystems Environ.,
Agriculture, Ecosystems and E n v i r o n m e n t , 29 (1989) E l s e v i e r S c i e n c e P u b l i s h e r s B . V . , Amsterdam Printed i n Czechoslovakia
MPN e s t i m a t e s
I.
o£ VAM d i a s p o r e s in c u l t i v a t e d
Jekobsen and T. Heidmann, A g r i c u l t u r a l
Rise N a t i o n a l
Laboratory,
199-203
soils
Research O e p a r t m e n t ,
0K-4000 R o s k i l d e and Research C e n t r e
Foulum, DK-8833 Orum S e n d e r l y n g ,
Denmark
ABSTRACT Most NPN e s t i m a t e s locations
samples from t h r e e
were i n t h e r a n g e 20-450 d i a s p o r e s
considerable limited
o f VAM d i a s p o r e s i n s o i l
variation
extent
within
be e x p l a i n e d
each l o c a t i o n by o t h e r s o i l
(100 9 s o i l ) "1
A
could only to a p a r a m e t e r s and
cropping history. INTRODUCTION The r a t e
of establishment
is influenced in the soil. bility
o f VA m y c o r r h i z a
by t h e number o f i n f e c t i v e More i n f o r m a t i o n
(VAH) i n a n n u a l crops
propagules
(diasporas)
i s needed on t h e v a r i a t i o n
o f d i a s p o r a numbers. The o b j e c t i v e
o f t h e p r e s e n t work was
t o d e t e r m i n e numbers n f VAN d i a s p o r a s a t w e l l - d e f i n e d points
in three
ent farming
fields,
sampling
where l o n g - t e r m e x p e r i m e n t s w i t h
systems have r e c e n t l y
and s t a -
differ-
been i n i t i a t e d .
MATERZALS ANO METHODS Ten s o i l
samples were c o l l e c t e d
locations
(Table 1).
i n t h e autumn from each o f t h r e e
O n l y b a r l e y o r wheat had been grown a t Odum
during the previous three
years,
while different
had been p l a c e d a t Jyndevad end Foulum u n t i l fore
sampling,
subsamples
when b a r l e y
crop r o t a t i o n s
the last
spring
was sown. Each sample c o n s i s t e d
be-
o f 12
($ 55 mm, 0 - 2 0 cm depth) t a k e n from an area o f 28 m2
200
around a defined p o i n t . with irradiated
S o i l was sieved (< 4 mm) and d i l u t e d
(10 kGy) s o i l
of the same sample. O i l u t i o n s were
eithe~ 2 - f o l d w i t h seven r e p l i c a t e
p l a n t s at each of s i x steps
(J) or l O - f o l d w i t h ten r e p l i c a t e s st each. of f i v e E). Cucumber p l s n t s were grown i n 60 g s o i l
lots
steps (F and
i n t r a y s placed
i n the greenhouse f o r 26 (J) or 28 (F and ~ ) . d a y s .
NPN e s t i m a t e s
were obtained from the number of i n f e c t e d p l a n t s as described by F i s h e r and Ystee (1963). Levels of YAH i n f e c t i o n i n p l a n t s from u n d i l u t e d s o i l
after
were recorded
11 end 26 d , y s
(J) or 28
days (F and E). Results were compared w i t h • wide range of p h y s i o - c h e m i c e l and b i o l o g i c s 1 parameters also measured at the 30 sampling p o i n t s .
Tab. 1. Some c h a r a c t e r i s t i c s
Location
F i e l d area
of the t h r e e sampling s i t e s
Soil type
(he)
pH
01sen P
(10"2M CeCl2)
(mg kg "1)
Jyndevsd (J)
18
coarse sand
5.2-6.2
37-55
Foulum (F)
25
loamy send
5.4-5.9
33-42
Bdum (B)
16
sandy loam
6.1-6.6
22-38
RESULTS The number of VAH diasporas v a r i e d c o n s i d e r a b l y between samples w i t h i n each l o c a t i o n
and i n s p i t e of the wide confidence i n t e r -
v a l of the s i n g l e estimates s i g n i f i c a n t ell
locations
(Fig.
cropping h i s t o r y
differences
appeared s t
1). Oisspore numbers c o r r e l a t e d
poorly with
end s o i l
v ~ r i e b l e e except at Jyndevsd where
201
significant ~0.76)
correlations
were o b s e r v e d .
from u n d i l u t e d tions
(Fig.
2).
ni£ican¢ly
late
In£ection
levels
plants
more c l o s e l y
not c l o s e l y
within
correlated
from u n s t e r i l e
with
than b~tween l o c a -
(r = 0.74,
Znfection
levels
Jyndevad s o i l
0.73,
and
measured
d i d nor c o r r e -
d i s s p o r e numbers.
JYNDEVAD 400
i n cucumber r o o t s
end d i a s p o r e numbers were s i g -
F, and ~, r e s p e c t i v e l y ) ;
22-day-old
and Olsen P ( r =
Levels of VAN i n f e c t i o n
were l e s s v a r i a b l e
although
0.78 £or J, in
soil
w i t h pH ( r = 0.74)
ODUM
1200
= 18o I
I
C,V =
11 ~.
T
1000
"~ 200
v)
BOO "0 0
o
0 0 q.,
0
~. f/J
600
FOULUM
P 400
o
=
0 n_
205
0
GV = 44
400
0
:E ~00 200
1 2
3
4
5
6
7
8
910
1 2 3 4 5 6 7 8 9 1 0
Somple No.
Somple No, 95~, confidence Intervols:
Fig.
JYNt)EVAD
0.59 MPN -
FOU~UM ~ ) ~DUM
0.4.3 MPN - 2.32 MPN
2. Number of VAH d i a s p o r e s
and Foulum.
1.69 MPN
i n samples from Jyndevad,
Odum,
202
40 JYNDEVAD X ' = 20 CV = 32 20
Hlii
0
m
rOU
_
40
}
•
o
~ 2o
-
I
c
X
0
-
'
ODUM
20
X=12 CV = 47
0 1
2 3 4 5 6 7 6 3 1 0
1
Sample No.
Fig.
2. Levels of VAM i n f e c t i o n
in 26-
(J) or 28- (F and 0) day
old cucumber plants grown in undiluted soil.
Z03
DISCUSSION Numbers o f VAN d i a s p o r a s i n t h e p r e s e n t work are i n t h e same r a n g e as found i n c u l t i v a t e d 1983).
soils
A l t h o u g h some v a r i a t i o n
i n U.K.
(Sanders and Sheikh
s t Jyndevad c o u l d be e x p l a i n e d by
s o ~ l P and pH t h e background f o r t h e o b s e r v e d v a r i a t i o n s largely
unexp!a'ined.
be t e s t e d
by f u t u r e
defined.points.. levels
HPN t e s t s
counts lay
shown t o
The p o s s i b l e populations future
of the single
estimates
between d i s s p o r e numbers and
were n o t c l o s e ,
possibly
above 50-100 (100 g s o i l ) " 1 ,
'saturate'
i,lportance
will
on ssmples from t h e same w e l l -
The r e l a t i o n s h i p s
of V A N . i n f e c t i o n
dias~ore ously
The s t a b i l i t y
remains
the roots
s range previ-
(Sanders and S h e i k h 1983).
of qualitative
is being investigated
because most
differences
end w i l l
i n t h e fungml
be c o n s i d e r e d a l s o i n
samplings.
REFERENCES FISHER, R . A . , cultural
YATES, F. S t a t i s t i C a l
and m e d i c a l r e s e a r c h .
SANOERS, F . E . , lsr
mycorrhizal
71:
223-246,
- Oliver
for
biological,
agri-
and Boyd, E d i n b u r g h ,
1963.
SHEIKH, N.A. The d e v e l o p m e n t o f v e s i c u i a r - a r b u s c u infection
in plant
root
systems.
- Plant
and S o i l
1983.
Jakobsen, I. and Heldmann, T., dlaspores in cultivated soils. 29:
tables
199-203~
1989: Agric.
MPN e s t i m a t e s o f VAM Ecosystems Environ.,