Studies on the Calcicole-Calcifuge Habit: II. The

Studies on the Calcicole-Calcifuge Habit: II. The

691
STUDIES
ON THE CALCICOLE-CALCIFUGE
HABIT
II. THE INFLUENCE OF CALCIUM ON THE GROWTH AND ESTABLISHMENT OF FOUR SPECIES IN SOIL AND SAND CULTURES
BY R. L. JEFFERIES
AND
A. J. WILLIS
ofBristol
ofBotany,University
Department
I. INTRODUCTION
& Willis 1964) indicatesthatthe
Evidencewhichhas been presentedearlier(Jefferies
calcifugespeciesJuncussquarrosusL. and NardusstrictaL. are plants possessingan
narrowdistribution
rangein respectof levelsof exchangeablesoil nutrients,
extremely
especiallyregardingcalcium. Sieglingiadecumbens(L.) Bernh.is tolerantof a much
widerrange,whereasOriganumvulgareL. is-restrictedto soils rich in exchangeable
to assessto whatextentthe
calcium.An attempthas beenmade,usingculturetechniques,
in
distribution
patternsof theseplants are determinedby the availabilityof nutrients
the soil.
typesof soil in orderto study
Plantsof thefourspecieshave been grownin different
theirabilityto become establishedin soils fromwhichtheyare absentundernatural
conditions.The plantsalso have been grownin sand culturesto whichmineralsolutions
to
havebeenadded suchthatthenutritional
statusoftheculturesprobablyapproximated
considerably
conditionsfoundin naturalhabitats.As theavailabilityof calciumdiffered
of
in thesoilswhichhave beenanalysed,particularattentionhas beengivento theeffect
in relationto the concentrationof the othernutrientson the
calcium concentration
establishment
and growthof thesespecies.
II. CULTURE
TECHNIQUE
Plantsweregrownunderglasshouseconditionsin polythene
pots,8 in. (20 cm) deep and
6 in. (15 cm) in diameter,or else in earthenware
pots of similardimensions.In orderto
excludeany possibilityof nutrients
beingderivedfromsourcesotherthan the culture
solutions,the precautionstaken were as recommendedby Hewitt(1952). The quartz
sand whichwas requiredformanyof the experiments
was purifiedin a Kestnersand
digester(Hewitt1952). At all timesde-ionizedwaterof specificresistancegreaterthan
fourmegohms(Willis & Yemm 1961) was used in thesestudies.When the seeds were
solutionwas allowedto percolatethrough
sownin sand, 1 1. of the appropriatenutrient
the culturein orderthatresidualacidityin-the sand shouldbe diminishedand thatthe
seeds would germinate
underthe same conditionsas theplantswould laterexperience.
In someculturestheseconditionsparalleledthoseofnaturalhabitats.In nearlyall ofthe
conditionson
of nutrient
experiments,
plantsweregrownfromseed,so thatany effects
thesestudies
been
used
in
if
had
couldbe elucidated; onlytransplants
plantestablishment
seeds of all
of
the
Germination
of thiskindwould not have been obtained.
information
did not
here
the
in
the
fourspecieswas foundto be satisfactory
temperature
glasshouse;
fallbelow 13?C and therewas no artificial
lighting.
Q
JE
692
of calcium
habit:influence
Calcicole-calcifuge
Seeds were collectedfromplants fromthe same sites each autumn.The seeds of
Juncussquarrosusand of Nardusstrictawereobtainedfromplantsgrowingon theacidic
peaty soil of Blackdown,Mendip (National Grid referenceST474572), of Sieglingia
froma populationon the fenpeat of the Gordano valley,northSomerset
decumbens
limestonesoil of
(ST437730) and of Origanumvulgarefromplantson theCarboniferous
CadburyCamp, northSomerset(ST455722).
The pots were distributedat randomin the glasshouseand periodicallymoved to
theplantswereharvestedand washedin deplaces.At theend ofan experiment
different
weremade beforethe
ionizedwaterfora shorttime;appropriategrowthmeasurements
by meansof
leafmaterialwas bulkedand thenanalysedforsome of themajornutrients
& Willis1964).
methodspreviouslydescribed(Jefferies
III. GROWTH AND ESTABLISHMENT OF THE PLANTS IN A RANGE OF
SOIL TYPES
status
To gainsomeindicationofthetoleranceoftheplantsto soiltypeand itsnutritional
theyweregrownfromseed in a numberof contrastedsoils whichdo not supportthese
speciesundernaturalconditions.Top soil was collectedat severallocalities,sievedand
mixedbeforeitwas used (Table 1). De-ionizedwaterwas added,as required,to duplicate
Table 1. The localitiesfromwhichsoils wereobtainedfor culturestudiesof thefour
of thesesoils
characteristics
species,and some important
as mgper 100g ofdry(80?C) soil.
The levelsofCa, Mg,K and Na are expressed
National
Na
Ca
K
Mg
Soil type
Gridreference
Site
240
80
27 5
898
Fen peat
ST437730
GordanoValley,
I
N. Somerset,
40
31-0
22-5
1164
Fen peat
ST435729
GordanoValley,
II
N. Somerset,
8-5
Carboniferous 664 114-0 19-0
ST455722
CadburyCamp,
limestone
N. Somerset
32 5
1-5
24-0
1252
Sand-dune
SS455345
BrauntonBurrows,
soil
N. Devon
pH
36
5-2
7-4
7-9
soil cultures.Numerousseeds of Origanumvulgareand ofJuncussquarrosusweresown
but in the case of Nardusstrictaand Sieglingiadecumbensonlyeightseeds weresown
perpot.The plantswereharvestedin November1961aftera growingperiodof20 weeks.
indicatedthatthe plantseitherdied shortlyafter
The resultsof thispilot experiment
or else showedpoor growthin most of the soils (Table 2). The data were
germination
as onlyfewplantssurvivedin each culture.Althoughthenumber
nottreatedstatistically
theresultssuggestedthatedaphicfeatureswerelikelyto be
of soilschosenwas restricted,
of considerablesignificance
in limitingthesespeciesto certainsoils. The poor developmentof all of the plants,includingOriganumvulgare,in the sandy soil of Braunton
ofthelow levelsofavailablenitrogenand phosphorusin
Burrowsis probablya reflection
in a soil
thiscalcareoussand (Willis& Yemm 1961).The abilityof 0. vulgareto flourish
the
on
has
some
signifibearing
of pH 3-6butrichin exchangeablecalcium(fenpeat,I)
and othersoil featureswhichvarywithpH, in
cance of hydrogenion concentration,
In thelocalitywherethissoil was collectedthewatertable
influencing
plantdistribution.
1959); itis possiblethatthisfeature
is nearto thesurfaceoftheground(Willis& Jefferies
R. L. JEFFERIES
AND A. J. WILLIS
693
mayexclude0. vulgarefromsuchsoils.The growthofindividualplantsofNardusstricta
variable.One of the onlytwo plants
in the Carboniferouslimestonesoil was extremely
the courseof theexperiment,
whichsurvivedremainedat theseedlingstagethroughout
whereasthe otherstayedat this stage for monthsbut subsequentlybegan to thrive.
after
Table 2. The averagedryweightof theshootsystemsof theplannts
typesof soil
for 20 weeksin different
growth
perplant.
The figures
givemgpershootsystem
Juncus
Sieglingia Origanum
Nardus
Soil type
squarrosus stricta decumbens vulgare
402
Fen peat,I
49
98-0
164
Died*
Fen peat,II
38 0
1-2
11-8
Carboniferous
147-0
limestone
soil
Died
50.0
26-0
13-0
2-0
Sand-dunesoil
Died
3-1
* Fungal attack.
Under naturalconditionsthe majorityof theseplantsundoubtedlywould die withina
shorttimein suchsurroundings,
and evenifa fewmanagedto survivefora longerperiod
lead to theirdeath.
fromotherspecieswould ultimately
probablycompetition
IV. EFFECT OF CALCIUM LEVEL ON THE GROWTH AND ESTABLISHMENT OF THE FOUR SPECIES IN SAND CULTURE
1
(1) Experiment
The aim of thisexperiment,
and of subsequentones describedin thissection,was to
on thegermination
and growthof
calciumconcentrations
elucidatetheeffects
ofdifferent
of
to providesimilarconcentrations
theplants.It seemeddesirablein a firstexperiment
1
Table 3. The composition
of theculturesolutionsusedin Experiment
1
3
Culturenumber
6
4
5
7
mgCall. as:
4
4
4
4
4
4
4
Ca(NO3)2
0
28
92
240
442
668
4
CaCl2
32
672
8
96
244
446
Totalcalcium(mg/l.) 4
Othernutrients
wereadded to all of the culturesolutions1-7 as
as mg/l.
follows;valuesare expressed
nitrate
Cu, 0 6, as coppersulphate
K, 16,as potassium
sulphate Zn, 0 65, as zincsulphate
Mg, 18,as magnesium
P, 12-2,as sodiumdihydrogen B, 3 0, as boricacid
and
Na, 25, as sodiumhydroxide
phosphate
sodiumdihydrogen
phosphate
Fe, 11-2,as ironcitrate
sulphate
Mn, 5 5, as manganese
2
the
in the culturesolutionsto those foundin naturalhabitats.Accordingly,
nutrients
of
to analyticaldata of the levels exfinalconcentrations
were adopted by reference
& Willis 1964) and were
in soils supportingtheseplants(Jefferies
changeablenutrients
also similarto thevaluesgivenbyGorham& Pearsall(1956) forthemineralcomposition
ofbog and fenwaters.
soluAlthoughthe amountsof calcium(as CaCl2) whichwereadded to the different
unaltered
remained
(Table 3).
tions were varied,the quantitiesof the othernutrients
of calcium
habit:influence
Calcicole-calcifuge
694
The pH of the seven culturesolutionswas adjustedto 5 0 (by NaOH); the driftenfromthe sand cultureswas
of the effluent
counteredin the hydrogenion concentration
solufoundon all occasionsto be betweenpH 4-5and 5-5.Additionsof 100ml ofnutrient
tionsweremadeweeklyto theduplicateculturesand thesandwas moistenedas required.
(a)
1004
100
-0
A
/
E
(b)
5
\
A?
75/'-
25 -u
~25-
\A
0
1~10
0
500
50
100
mg Ca/I
4
10
500o
50
100
mg Ca/l
levelsofcalciumsuppliedas
different
ofplantsin culturescontaining
FIG. 1. The growth
chloride.Details of thesevenculturesolutionsused are givenin Table 3; calciumconis shownon a log scale. Mean dryweightsof theshoots(a) and roots(b) of
centration
*;
vulgare,
0; and Origanum
decumbens,
*; Sieglingia
*; Nardusstricta,
Juncus
squarrosus,
are plotted.
Table 4. Analysesof leaf tissueof Juncussquarrosusand dryweightsof theplants
in cutlture
experiments
3 as in all theseculturesall theplantsdied.
No resultsare includedforExperiment
mgCa/l.
Plantsofnaturalhabitats
Minimum
Maximum
Mean
1
Experiment
Culture1
Culture2
4
8
2
Experiment
Culture1
Culture2
Culture3
Culture4
4
8
32
96
4
Experiment
Culture1
Culture2
12
24
drywt.
mg/g
Na
Mg
K
0-3
0-9
063
1.1
2-3
1-5
100
18 6
150
1-8
6-3 10-7 4-6
Sampleslost
Ca
1-7 59
2-5 6-5
6-3 6-9
24-0 -65
130
122
12-6
10-8
Meanwt./shoot Mean wt./root
of
(mg)
of
(mg)
(O%
45
41
100
91
32
27
100
84
51
57
41
22-5
89-5
100
72
39 5
415
58
13
7
71
100
22
12
10
7-3
100
73
6
5
100
83
max.)
(O%
max.)
05
1-9
10
2-6
3-9
7-8
5-5
Not enoughmaterial
foranalyses
vulgareweresownbutthenumber
and of Origanum
NumerousseedsofJuncussquarrosus
was limitedto sixteenand eight
of seeds of Nardusstrictaand of Sieglingiadecumbens
was begunin May 1960and theplantswereharvestedaftera
The experiment
respectively.
periodof 28 weeks.
R. L.
JEFFERIES AND
A. J.
695
WILLIS
The resultsof the growthof thesefourspeciesexpressedin termsof dryweightare
in survivaland in growthmade
shownin Fig. 1, and also in Tables 4-7. The differences
by the plantsin the cultureshavingvariouslevelsof calciumare evidentfromFig. 1.
affect
thegrowthofthe
Althoughtheresultssuggestthatthedifferent
culturetreatments
Table 5. Analysesof leaf tissueof Nardus strictaand dryweightsof theplantsin culture
experiments
withinan experiment
Wherethedryweightsoftheplantsgrownunderthevariousculturetreatments
different
difference
is shown.
are significantly
(5 % level)theleastsignificant
(L.S.D.) fortheexperiment
mgCa/l.
Plantsofnatural
habitats
Minimum
Maximum
Mean
Ca
mg/gdrywt.
Mg
K
Na
Mean
wt./shoot
(mg) (% of
max.)
09
16
13
09
1-8
14
50
11-5
79
0.1
08
03
1-6 69
1-6 93
1-3 103
83
07
4-1 39
1
Experiment
Culture1
Culture2
Culture3
Culture4
Culture5
4
8
32
96
244
0-6
1D1
2-4
4-8
11-7
29
2-8
3-2
2-8
26
9-2
11-8
12 8
15-0
10 4
2
Experiment
Culture1
Culture2
Culture3
Culture4
Culture5
L.S.D.
4
8
32
96
244
0-8
10
2-0
30
27-9
30
3-1
3-2
19
4-8
76
70
52
4-3
6-8
3
Experiment
Culture3
192
4-4
3-4
12 2
1-7 112
4
Experiment
Culture1
Culture2
Culture3
L.S.D.
12
24
96
2-3
22
4-7
37
3-1
2-5
8-3
100
70
5
Experiment
Culture1
Culture2
Culture3
Culture4
Culture5
Culture6
Culture7
Culture8
L.S.D.
04
08
32
9-6
24-4
44-6
67-2
89-6
3-7
3-5
27
2-9
7-0
9-6
12-5
12-4
41
1-2
1-3
1-7
1-7
1-5
2-8
2-3
5-4
10-3
5-8
3-4
1-4
2-4
3-2
1-2
67
90
100
80-5
38
Mean
wt./root
(mg)
35
51
58
27
9
No.
of
(% of seeds
No. of
plants
max.) sown harvested
60
88
100
47
15
16
16
16
16
16
12
15
16
9
1
26
32
70
100
15
15
15
15
15
15
12
9
12
10
3
100
12
3
2-0 37
1-4 88
1-7 163
80
22-5
54
100
12
12
12
11
12
7
2-1 50
8-9 25
50
49
0-8 97
0-8 93
0 4 210
1-6 135
0-8 235
107
21
105
21
41
39
89
57-5
100
10
10
10
10
10
10
10
10
5
8
5
6
9
6
4
4
09
07
04
11
16 6
56
77
195
301
74
138
18 5 58
25 5 70
65
155
220
100
24-5 32
88-5
plantsto a considerableextent,statisticaltestsmade by means of thevariance-ratio
(Ftest)and multiplerangetest(Duncan 1955)showedthat,in respectofmeandryweightsof
and Nardusstricta,differences
shootsand rootsof Sieglingiadecumbens
from
resulting
in theplantswhichsurvived,did not quitereachsignifithevariousculturetreatments,
cance at the 5% levelof probability.
However,in thisexperiment
onlya relatively
small
of calcium
habit:influence
Calcicole-calcifuge
696
Table 6. Analysesof leaftissueof Sieglingiadecumbensand dryweightsof theplantsin
cultureexperiments
withinan experiment
oftheplantsgrownunderthevariousculturetreatments
Wherethedryweights
is shown.
(L.S.D.) fortheexperiment
difference
(5 % level),theleastsignificant
different
are significantly
mgCa/I.
Plantsofnatural
habitats
Minimum
Maximum
Mean
Ca
mg/gdrywt.
Na
K
Mg
09
40
19
04
2-8
1-3
50
14 4
101
03
55
19
1-8
19
1-6
18
19
90
1
Experiment
Culture1
Culture2
Culture3
Culture4
Culture5
Culture6
4
8
32
96
244
446
1P7
2-0
47
95
195
14 3
59
5-5
50
40
46
3-1
15 3
119
124
12 1
129
15 1
2
Experiment
Culture1
Culture2
Culture3
Culture4
Culture5
L.S.D
4
8
32
96
244
1-2
21
40
70
23 5
61
49
50
3-5
39
76
75
93
7-3
56
3
Experiment
Culture1
Culture2
Culture3
24
48
192
69
5-8
119
53
38
4-5
4
Experiment
Culture1
Culture2
Culture3
Culture4
L.S.D.
12
24
96
288
5
Experiment
Culture1
Culture2
Culture3
Culture4
Culture5
Culture6
Culture7
Culture8
Culture9
L.S.D.
04
08
3-2
96
24 4
44 6
67-2
89-6
131-2
No.
Mean
Mean
of No. of
wt./root
wt./shoot
(mg) (% of (mg) (% of seeds plants
max.) sown harvested
max.)
70
100
96 5
945
93
66 5
80
127
96
100
31
39
63
100
76
79
24
31
8
8
8
8
8
8
7
6
8
6
4
7
1-5 19
04
71
2-3 112
2 9 310
6-4 46
40
6
22
36
100
14
22
101
138
253
30
37
9
40
55
100
12
12
12
12
12
12
10
11
11
9
7
16 9
13 2
17 2
2 1 24
1-8 101
19
34
23-5
100
33 5
8
8
8
1
5
1
54
19
3-7 3 9
11 9 12-8
58
550
13 3
105
63
3.3
1 9 157
08 196
11-4 151
8 3 72
92
80
100
77
365
8
8
8
8
6
6
5
4
11 2 1
1-8 4 5
2-5 07
4-8 1 8
9*9 2 2
12 0 2-3
11
142
16 7 4 4
22-7 10 1
53
30
4.7
4-5
3-4
2-6
30
5-1
10 1
6
6
6
6
6
6
6
6
6
3
4
3
4
4
2
2
3
1
1-3
10
07
07
08
03
06
19
19
99
141
136
133
131
94
41
89
52
24
12-5
27
58
125
144
66 5
86
186
216 100
61-5
133
34
73
56 5
R. L. JEFFERIESAND A. J. WILLIS
697
numberofplantswas studied.In additionto valuesof dryweights,resultsof analysesof
as wellas thedata of some subsequentones,are summarleaf tissuesin thisexperiment,
ized forconveniencetogetherin Tables 4-7. Here also are includedthevaluesforleast
differences,
in dryweightsof shoots and roots of plants grownunderthe
significant
different
levelsofcalciumsupply,calculatedbythemultiplerangetestprocedure(Duncan
were
in whichdifferences
on N. strictaand Sieglingiadecumbens
1955) forexperiments
oftheplantsinculture
Table 7. AnalysesofleaftissueofOriganumvulgareanddryweights
experiments
mgCa/I.
Plantsofnatural
habitats
Minimum
Maximum
Mean
mg/gdrywt.
Ca
Mg
K
Na
9-8
23.1
16-5
14
80
4-3
9-2
28.8
16-5
0.1
04
03
Mean wt./shoot Mean wt./root
(mg)
(% of
(mg)
(% of
max.)
max.)
1
Experiment
Culture3
Culture4
Culture5
Culture6
Culture7
32
96
244
446
672
9.1
11 1
13-0
26 2
29 5
85
25 3
65
56
17 5
16 9
5-4
Sampleslost
05
0o4
08
07
11
22
57
75
72
14-5
29
76
100
96
14
20
40
53
48
26
38
75-5
100
90 5
2
Experiment
Culture3
Culture4
Culture5
Culture6
Culture7
Culture8
Culture9
32
96
244
446
672
896
1312
2-8
57
316
19.1
53
37-1
69 6
40
4-2
52
5.9
40
2-6
4-1
8.4
44
4-3
43
4'3
4-7
94
02
0.1
17
1.1
1.5
07
2-0
45
39
88
164
143
130
37
27 5
24
53-5
100
87
79
22-5
24
18
36
52
42
32
12
46
35
69
100
81
62
23
3
Experiment
Culture3
192
4
Experiment
Culture2
Culture3
Culture4
24
96
288
5-4
14 2
13-7
4-4
45
3'0
7-8
24
14
5
Experiment
Culture5
Culture6
Culture7
Culture8
Culture9
24 4
44-6
67-2
89-6
131-2
25 7
29 2
38-0
62 7
45-7
26-7
19-7
21-5
240
15-0
5.3
48
8-5
50
3-8
11
100
5
100
1.0
1-5
16
115
102
120
96
85
100
39
54
29
72
100
54
9-6
45
9.1
100
12-5
30
40
40
56
76
39 5
52 5
52-5
73-5
100
27
32
37
42
58
46.5
55
64
72-5
100
Not enoughmaterialfor
analyses
at leastat the 5% level.No statisticalanalyseswerepossibleof theresultson
significant
in separating
Juncussquarrosusand Origanumvulgare,partlybecause of the difficulties
same
cultures.
the
in
the
completely rootsof theplantsfromthoseof others
was
In Experiment1 in culturespossessinghighcalciumconcentrations
germination
cultures
in
such
or
did
not
to
else
occur.
Seeds
of
failed
Juncus
germinate
squarrosus
delayed
are
ofseedsof Origanumvulgarewas retarded.These observations
whilethegermination
in generalagreement
withthefindings
of Webb & Hart (1945). Whereas0. vulgareand,
at thesehighcalcium
to a lesserextent,Sieglingiadecumbens
werecapable of surviving
698
of calcium
habit:influence
Calcicole-calcifuge
and becomingestablished,Juncussquarrosusand Nardusstrictaquickly
concentrations
was fixedabout 4 weeks after
succumbed;consequentlythe course of the experiment
conductedwhichinvolvedthe
This was evidentin all of the experiments
germination.
growthof plantsfromseeds.
Juncussquarrosusand, to a lesserextent,Nardusstrictawerelimitedto the cultures
resultsthat
whichcontainedlow calciumlevels; it would appear fromtheexperimental
Juncussquarrosusis a strictercalcifugethan Nardus stricta.This is consistentwith
madein naturalhabitats,foralthoughNardusis capable ofgrowingat very
observations
highercalcium
low calciumlevelsitwas foundmoreoftenin soilswhichhavesubstantially
& Willis1964).
levelsthanthosesoilsin whichJuncussquarrosusis established(Jefferies
Origanumvulgarecannotsurvivein theculturespossessinglow calciumconcentrations.
In such culturesthe seedlingswere small and stuntedand showedcalciumdeficiency
symptomsin theirleaves and at the growingpoints.Sieglingiadecumbenssurvivedat
in
highercalciumlevelsthan Nardusstricta,whichis in keepingwithits distribution
naturalhabitats.
is that with increasingcalcium concentration
A notablefeatureof this experiment
therewas usuallypoorerroot development.This observationof deleteriouseffectsof
of Olsen (1942),
withthefindings
highcalciumlevelson growthis in generalagreement
Webb & Hart (1945) and Rorison(1960). N. strictaat thehighercalciumlevelsformed
oflateralswhereasat thelowercalciumlevels
shortstuntedrootswithpoor development
therewas a profusedevelopmentof root lateralsforminga mattedgrowth.
ofthesespeciesin thevariousculturesare
in growthand establishment
The differences
withtheresponseoftheplantsto thewidevarietyof soil conditionsin natural
consistent
the quantityof nutrientsin the shoot tissuesof each of these
habitats.Furthermore,
speciesshowedsome parallelismto thatin the plant materialcollectedfromthe field
is clear.
(Tables 4-7). In the case of Juncussquarrosusand Nardusstrictathe similarity
However,in cultureswherethe levelof calciumis highand the growthof theplantsis
fromplants of naturalhabitatsin respectof
poor, thereis a considerabledifference
in thetissues,especiallyof calcium.The same observationis applicamountsof nutrient
able to Sieglingiadecumbens.At low calcium levels an accumulationof monovalent
takesplace.
cationsin thetissuesof all fourspecies,but especiallyofJuncussquarrosus,
Magnesiumcontentis also highin theshootmaterialofall ofthespeciesbutit decreases
withincreasedcalciumintheculturesolutions.Theseobservations
in Sieglingiadecumbens
King & Handley(1950),
are in agreementwithearlierfindingsof Jacobson,Overstreet,
Epstein(1961), Snaydon& Bradshaw(1961) and others.Thereis no positiveindication
thatincreasingthe calciumcontentof the
fromthe analyticaldata of thisexperiment
culturesolutionresultsin a decreasein the uptakeof potassium,exceptpossiblyin the
case of Origanumvulgare(Fig. 7). However,becauseofpoor growthofplantsin cultures
betweenions duringsaltuptake,considerable
whereone mightexpectseverecompetition
of interpretation.
analyticalproblemsariseas well as difficulties
2
(2) Experiment
was similarto Experiment1, exceptthatcalciumnitratewas the sole
This experiment
sourceofcalcium,calciumchloridebeingreplacedbythenitrate.Bychangingtheanionit
was possibleto exploreto whatextentthechlorideion accountedfortheresultsobtained
The procedureadoptedwas as previouslydescribedexcept
in theprecedingexperiment.
thattherangeof thecultureswas increasedto includetwo additionalhigherconcentrations of calcium.Cultures1 to 7 were of the same calciumlevelsas in Experiment1,
699
R. L. JEFFERIES
ANDA. J. WILLIS
896 and 1312mgCa/l.The amountsof other
butcultures8 and 9 contained,respectively,
nutrientsin the culturesolutionswere as shownin Table 3. The seeds were sown in
March 1960 and theplantsharvestedin August1960.
The results,includedin Tables 4-7, are essentiallysimilarto those givenearlierin
squarroindicating
theinabilityoftheplantsto growin particularcultures(Fig. 2). Juncus
highcalciumlevels,
sus and Nardusstrictafailedto becomeestablishedin sandcontaining
as did Sieglingiadecumbens.In cultureswhich containedsmall amountsof calcium,
Origanumvulgarewas unableto surviveand theleaves showedseverecalciumdeficiency
as well as nitrogendeficiency.
at thelow calciumconcentraThe growthof Nardusstrictaand Sieglingiadecumbens
low (Tables 5 and 6). This poor growthwas also
tions was foundto be significantly
forin thepreviousexperiment
probablya reflection
of thelow levelof availablenitrogen,
(a)
100
E 75
AU
(b)
100U
'.
75
/
O
/
450
/
L75
0
4
10
50
. .
~~~~~~~~~25~~
in
50
100
mg Ca/L
/
500 1000
0
4
10
50
100
mg Ca/l
500
1000
levelsofcalciumsuppliedas
different
FIG.2. The growthofplantsin cultures
containing
was
nitrate.The graphis constructed
in the same way as Fig. 1, but the experiment
extended
to twoadditionalhighlevelsofcalcium(cultures8 and 9). Juncus
squarrosus,
@;
vulgare,
v.
Nardusstricta,
A; Sieglingia
decumbens,
0; Origanum
wherethenitrogen
levelswereconstantthegrowthmadebythesetwo specieswas similar
The analysesofplant
and substantialin culturescontaininglow calciumconcentrations.
tissue(Tables 4-7) also yieldedsomewhatsimilarresultsto thoseof thepreviousexperimentbut again indirectevidenceof ion antagonismduringsaltuptakeis lacking.In all
fourspecies,a highconcentration
of calciumin theculturesresultedin largeamountsof
calciumin theleaftissue.
havebeenfoundin naturalhabitatswhere,
and Origanum
vulgare
AlthoughS. decumbens
such
in the soil, the ratio of exchangeablecalciumto the otherexchangeablenutrients
as potassiumand sodiumis high,at similarratiosin theculturestheplantsdied or else
of calciumwas different
from
showedpoor growth.It is probablethattheconcentration
thatexperiencedunderfieldconditions,as discussedlater,and thisfeaturemayaccount
forthe resultsobtained.However,thepossibilityexiststhatsuch a speciesas Sieglingia
decumbens
may be composedof a numberof distinctpopulations,some of whichare
establishedon chalkand limestonesoils.Whenseed of
capable of becomingsuccessfully
Sieglingiawas used whichhad been collectedfromBrauntonBurrows,a highlycalcareoushabitat,thegrowthof theseplantsin sand culturesgave similarresultsto those
alreadypresented.Some explanationotherthan the existenceof distinctpopulations
of calcium
habit:influence
Calcicole-calcifuge
700
soughtto accountforthe inabilityof thisgrassto growin culturesconwas therefore
indicatethatedaphic
taininghighlevelsofcalcium.The data presenteddo notnecessarily
workis required
do not occurand clearlymoreexperimental
ecotypesof S. decumbens
involvingseedscollectedfroma largenumberofhabitatsin orderto solvethisproblem.
3, 4 and 5
(3) Experiments
in whichtheculturesolutionapplied
on
experiments
The resultsgivenabove are based
exceptforthe level of the
of
nutrients
to the sand containedthe same concentration
to
the
othercations in these
calcium
ratio
of
the
particularcalcium salt. Although
(based on
investigated
were
solutionswas similarto the ratios found in soils which
E100
EXPT.4
EJ
I
~~~
50
12
Plants died
50
I.
500
100
mg Ca/l
1000
3000
1
I
EXPT. 2
~~~~~~~~~~~~~~~~~~Plants
.
I
4
10
idied
100
50
mg Ca/L
500
1000
levelsof calcium.
different
in culturescontaining
squarrosus
FIG. 3. Growthof Juncus
The meandryweightoftheshootsis shown.
exchangeableion levels),some of the speciesfailedto growin certaincultures,as disof mineralsin
cussedearlier.This mayhave been caused,in part,by the concentration
the sand culturesnot beingthe same as that experiencedby the roots undernatural
conditions.The resultsofthesoil analysesare based on unitweightand suchdata maybe
misleadingifa numberof soil typesare beingcompared(Fried & Shapiro1961; Jefferies
& Willis 1964).
Plants died
Plnts
EXP
died
ro
E
100
24
500
1000
5000
4
10
50
100
500
1000
0
0
FG0
EXPT.4
.
1eXPTa
50-
cm
mg Ca/L
mg Ca/L
different
levelsof calcium.
FIG. 4. Growthof Nardusstrictain culturescontaining
were set up whereadditionsof nutrients
To investigatethis problem,experiments
weremade based on thesameratiosofcalciumto otherions as previouslyemployedbut
was changedfromthatoftheearlierexperiments
ofall ofthenutrients
theconcentration
werechosenwhichwere,in respectof all of
by the same factor.Three concentrations
701
ANDA. J. WILLIS
R. L. JEFFERIES
the nutrients,six times (Experiment3), three times (Experiment4), and one-tenth
involvingcalciumnitrate
used in the experiment
(Experiment5), of the concentrations
(Experiment2). However,as in Experiment1, calciumchloridewas the main calcium
sourceand not calciumnitrate.In each of the Experiments
3-5, nine culturesolutions
1002
EXPT1
EXPT.1
3
00151
T<
ii
50--
ro
0
0
~~~~~~~~~~EXPT.4
100
o
24
mq Ca/l
30000 4
1000
500
5000
0
10
E XPT. 5
50
500 1000
0
mg Ca/
1I
04
3000
10
10
0
decumbens
in culturescontaining
different
FIG. 5. Growthof Sieglingia
levelsof calcium.
I
were10
rangedfrom7872 mg/I.in culture9
wereemployed;thetotalcalciumcontenttherefore
procedure
of Experiment3 to 0 4 mg/l.in cultureI of Experiment5. The experimental
was as previouslydescribedbutbecause ofthelargenumberofpotsrequiredforreplicathe
at thesame time;consequently
tionit was not possibleto startall threeexperiments
resultsare not directlycomparableand can be expressedon a relativebasis only.
100[
EXPT. 3
It I9
died
Plants
E
@
24
~100
Plants did
12
50
500
!
100
4
10
50
4
1
5
10
mg Ca/l
Ilill
500
1000
0
100
sdied
|PLant
100
5000
1000
I
EXPT. 2
500
mg Ca/l
50
00
levelsof calcium.
of Origanumvulgarein culturescontainingdifferent
FIG.6. Growth
in Juneand in May 1960and all
3 and 4, seedsweresown,respectively,
In Experiments
5, seedsof Nardusstricta
of theplantswereharvestedin December1960.In Experiment
weresown in September1960,and the plantsharvestedin
decumbens
and of Sieglingial
vulgarewere sown in September1960 and the plants
July1961; seeds of Origan7um
of calcium
habit:influence
Calcicole-calcifuge
702
harvestedin December1960; and seeds of Juncussquarrosusweresownin August1961
was undertaken.
but no detailedharvesting
The growthmade bytheplantsis shownin Figs. 3-6. Statisticaldata, dryweightsand
in the leaf tissuesare givenin
the resultsof the analysesof variousmineralnutrients
Tables 4-7. The resultsindicatethatthepatternof behaviourof all fourspeciesin these
conditionsis moreproculturesis essentiallysimilar,althoughtheresponseto different
of all of the nutrients
nouncedin some of the species.An increasein the concentration
of the plantsto cultureswherethe ratio of calciumto the other
leads to the restriction
in
althoughjust surviving
cationsis low,as foundin a non-calcareoussoil.J. squarrosus,
diesin all cultures
ofnutrients,
suchcultureshavingthreetimestheoriginalconcentration
of Experiment1. The establishment
of nutrients
whichhave six timesthe concentration
restricted
in culturesis likewiseprogressively
of Nardusstrictaand Sieglingiadecumbens
Origanumvulgarebehavesin a similarmanner,
ofnutrients.
thehighertheconcentrations
wheretheratioofcalciumcomparedto
onlyin culturesofhighconcentrations
surviving
is low.
othernutrients
60 /a
a)
'
40A
*
15
30
10(b)
20
5;
C:20
100
50
mg Ca/l of culture solution
10
FIG.
2 50
\
E 10===
30
50
mg Ca/l
300
100
of culture solution
450
7. Thechangesinlevelsofcalcium(0), magnesium
(A) intheleaves
(o) andpotassium
calcium
of (a) Sieglingiadecumbensand (b) Origanumvulgrare
grownin culturesof different
levels. For Sieglingia decumbensthe levels of magnesiumand potassium were constantin
the culture solutions at 54 and 48 mg/I.respectively(Exp. 4). For Origanumvulg'arethe
levelsofmagnesiumand potassiumwereconstantin theculturesolutionsat 18 and 16 mg/I.
respectively(Exp. 1).
Inabilityto survivein such culturesdoes not appear to be an osmoticeffectas the
culturesolutionis onlyaboutfiveatmospheres.
osmoticpressurein themostconcentrated
is protracted.Poor growthof
but further
The seeds germinatesuccessfully
development
amountsof nutrientsin the
plantsin theseculturesis associatedwithwidelydiffering
leavesas comparedwiththoseofplantsin naturalhabitats.An increasein calciumin the
mineralsolutionsnot onlyleads to a greateraccumulationof calciumin theplanttissue
and potassium(Tables4-7).
butitis also oftenassociatedwitha lowerlevelofmagnesium
This is especiallyevidentin Sieglingialdecumbensand in Origalnum
vulgare(Fig. 7).
Whethertheseresultsrepresentactiveaccumulationor just Donnan exchangereactions
is not known.
2 thereis a relatively
of Experiment
oftheconcentrations
In cultureshavingone-tenth
widerangeof tolerancebyall fourplants;heresomeplantsbecomeestablishednot only
is low but also in cultures
in cultureswherethe ratio of calciumto the othernutrients
whereit is similarto thatfoundin a calcareoussoil. Nardusstrictaand Sieglingiadecumis high.The
wheretheratioofcalciumto theothernutrients
bensgrowmostsuccessfully
R. L.
JEFFERIES AND
703
A. J. WILLIS
conditions
underexperimental
resultsindicatethatit is possibleto growS. decumbens
is similarto thatin a calcareoussoil.
wherethe ratio of calciumto the othernutrients
Nardusstrictabehavedin a similarfashion,yetwiththe exceptionof a fewcontinental
localities(Klika 1936) thereare no recordsof thisplant growingon limestonesoil. It
in theseparticularsand cultures
ofnutrients
is probable,however,thattheconcentration
involvingJuncus
is low comparedwiththatof calcareoussoils.Althoughtheexperiment
theconcentraitwas clearthat,evenin culturesof one-tenth
was discontinued
squarrosus
2, theplantgrowsonlyat thelow calciumlevels,dyingin therestof
tionsof Experiment
of
indicatethat,dependingupon the concentration
the cultures.The resultstherefore
it is possibleto growat leastthreeofthesespeciesin a rangeof cultureswhere
nutrients,
considerably.
differs
theratioof calciumto the othernutrients
V. THE EFFECT OF CALCIUM LEVEL ON TRANSPLANTS
6
Experiment
to
plantsgrownfromseed ratherthanto
refer
described
previously
of
results
All the
to discoverhow far similar
undertaken
was
A
experiment
pilot
of
transplants.
studies
resultsto thosegivenabove could be obtainedwhenvigorousyoungplantsweretransculturesolutions.
ferredto different
of Nardus strictaand Sieglingia
Table 8. Dry weightsof transplants
calciumlevels
decumbensgrownin culturesof different
and the average
Four plantsweregrownundereach treatment
(g) ofshootsand rootsperplantare given.
initialandfinalweights
Culture
a
b
c
Total
calcium
(mg/l.)
32
446
1312
Initialweightof
transplants
Nardusstricta
Shoot
Root
3-2
4-8
3 75
4-2
3-0
1.15
0 40
0 37
Sieglingia
decumbens
Root
Shoot
1-38
1.5
055
105
0-25
05
0-32
0-20
weregrownfromseed in cultures
Plantsof Nardusstrictaand Sieglingiadecumbens
was low (thesolutionwas thatused for
wheretheratioof calciumto theothernutrients
in October1960,after
culture3, Experiment1) and thensome of themweretransferred
a growingperiodof4 months,to cultureswheretheratioofcalciumto theothernutrients
was high.In all, the effectof threecultureregimeswas investigated:culturea was the
culturein whichtheplantswereraised,b was thesameas culture6 of Experiment1, and
c was similarto culture9 of Experiment2 exceptthat calciumwas presentchieflyas
the chloride.The levels of calciumare givenin Table 8. From October1960theplants
weretreatedwiththe appropriateculturesolutionsat the rateof 100 ml per weekuntil
was terminated.
August 1961 whenthe experiment
of both speciessurvivedin the
It is evidentfromtheresults(Table 8) thattransplants
showedthat
cultureswhichcontainedhighcalciumlevelsalthoughearlierexperiments
not
were
nearlyso
theseedlingsdiedin suchcultures.This indicatesthattheadultplants
the
Moreover
cultures.
the
in
sensitiveas the seedlingsto thelevelsof mineralnutrients
here
and
kind
reported
of
the
onlyin studies
resultsshowthedangerof usingtransplants
704
of calcium
habit:influence
Calcicole-calcifuge
solelyon thedata obtained.Thispointhas beenstressed
basingecologicalinterpretations
by Rorison(1960).
VI. DISCUSSION
The experiments
indicatethatit is possibleto growthe fourspeciesstudiedundernutritionalconditionswhichapproximately
parallelthosefoundin theirnaturalhabitats,
and theevidencesuggeststhattheconcentration
of calciumrelativeto theconcentration
plantdistribution.
of othernutrients
in the soil may be an importantfactoraffecting
Analyses of the soil supportingJuncussquarrosusshowed that the exchangeable
& Willis
measured(Jefferies
calciumlevelis similarto the levelsof the othernutrients
was probablyfar
of nutrients
1964). Exceptin Experiment5, wherethe concentration
belowthatfoundin naturalhabitats,J.squarrosus
failedto becomeestablishedin cultures
whichpossessed a fairlyhighratio of calciumto the othernutrients.Under natural
are normallyfoundin mineral
conditionshighratiosof calciumto the othernutrients
of nutrients
in the soil solutionis probablymuchhigher
soils; herethe concentration
thanthatin mostorganicsoils and theplantdoes not surviveat theseratios.
Nardusstrictadoes not appear to be such a strictcalcifugeas Juncussquarrosus.It
growssuccessfully
in naturalconditionsnot onlywheretheratioof calciumto theother
conis 1: 1 but also whereit is as muchas 7: 1. Underexperimental
major nutrients
of all
ditionsthisplantwas capable ofgrowingat suchratiosprovidedtheconcentration
was nottoo high.
nutrients
Sieglingiadecumbens,althoughmore prevalentin non-calcareoussoils, is found
growingon chalkand limestonesoilswheretheratioofcalciumto each oftheothermajor
nutrients
is extremely
high.Again,bychoosingappropriate
measured,exceptmagnesium,
it was possibleto growthisgrassin cultureshavingratios
concentrations
of nutrients,
of calciumto theothernutrients
in naturalhabitatswhereit
similarto thoseexperienced
flourishes.
ofthedistriin an understanding
The resultsobtainedare probablyimportant
butionof thisplant.S. decumbens
showsmarkedlyhighabundanceon chalksoilsin the
wettestregionsofthewestern
chalkin Britain(J.F. Hope-Simpson,personalcommunication). Whereit growson the chalk in East Angliaand south-eastEnglandthesitesare
generallyeitherchalk heaths(Tansley 1949) or else the localitieshave a highhumidity
in thewesternhalfof thiscountrypossibly
(Perring1960).The highrainfallexperienced
limestoneand chalksoils and
leads to a leachingof the surfacelayersof Carboniferous
of
thusa loweringoftheconcentration
ofnutrients
in theselayers,whilethedevelopment
chalkheathin theeasterncountiesproducesa similarresult.Undertheseconditionsthe
to allow S. decumbensto
concentrationof nutrientsis possiblylowered sufficiently
colonizesuchsitesand becomeestablished.Howeverit wouldappearthattheconcentrationis not low enoughforNardusstrictato establishitselfin thesehabitats.
ofSieglingia
Similarconsiderations
maybe advancedto explain,inpart,thedistribution
resultsof a
decumbenson Carboniferouslimestoneand sand-dunesoils. Preliminary
surveyof calcareoussoils in whichthisgrassgrowsindicatethatsitesbearingtheplant
have soils in whichthe humusand watercontentare highrelativeto those of soils of
comparablesitesfromwhichitis absent.Thereare also indicationsthatin localitieswhere
of the other
the plant growsat fairlyhigh calciumconcentrations
the concentrations
in thewintermonths.
are also high.Seeds of S. decumbens
nutrients
appearto germinate
Duringthisperiodthereis heavyrainfalland poor evaporation,and probablyconsiderlow calciumconable leachingof the surfacelayerstakes place, leadingto a relatively
centration.
ANDA. J. WILLIS
R. L. JEFFERIES
705
evidence
oftheseedling.Experimental
The discussionabove refersto theestablishment
suggeststhatwhentheplanthas reachedtheadultstageitis able to toleratemoreextreme
conditions.There is some evidencethat the roots of matureplants of S. decumbens
calcareous rock material.Whethersuch roots are actively
are capable of penetrating
ofions intotheplantis unknown.Howeverin theobservations
involvedin thetransport
madein thepresentstudy,therootsystemofthisspecieswas foundto be confinedto the
surfacelayersin calcareoushabitats.
Origanumvulgareis a calcicoleplant; the resultsfromExperiments1 and 2 indicate
ofcalciumdeficiency.
thatitis unableto growat low calciumlevelsand showssymptoms
2 theplant
of culture9 in Experiment
Howeverat the veryhighcalciumconcentration
poor growth.Thismayhave beenbecausetheconcentration
was foundto showrelatively
undernatural
of calciumin thesecultureswas higherthanthatwhichtherootsexperience
conditions.However0. vulgarehas beenregardedas a 'marginalcalcicole'(Praeger1950;
in part of its poor responseto
Clymo 1962)and the presentresultsmay be a reflection
veryhighcalciumconcentrations.
calcium
Althoughsimilarresponsesof each of thefourplantsare shownat different
levels,theresultssuggestthesame patternof behaviourof thefourplantsto alterations
in thecalciumlevelsin thenutrient
solutions.This poses the questionas to the nature
of the mechanismsgoverningtheseresponses.It is postulatedthatcalcicoleplantsare
ions whichare
considerablymoreselectivethancalcifugeplantsregardingthe different
low net
in calcicole plantsmay involve,in part,a relatively
absorbed.This selectivity
uptake of calciuminto the tissuewhen theseplants are grownin calcareoussoils. In
and such plantsgrowingunder
may not be so efficient
calcifugeplantsthis selectivity
highcalciumregimesabsorbconsiderableamountsofcalciumintothetissueat theexpense
of othercations.
In a comparativestudyof thegrowthof fourspecies,Sinapisalba, Dianthusbarbatus,
of
Hordeumdistichumand Tussilagofarfara,in solutionsof different
concentrations
calcium,Olsen(1942) foundthat,exceptforT.farfara,increasedcalciumlevelsresultedin
diminishedamountsof potassiumand magnesiumin the leaves. In contrast,in the calcicoleT. farfara,increasedcalciumin thenutrient
solutionled to increasedabsorptionof
in theabilityof rootsto absorbmaybe
potassium.It is possiblethatsimilardifferences
involvedin ironuptake,and mayexplainin partthephenomenonofironchlorosiswhich
is oftenobservedwhencalcifugeplantsare grownin calcareoussoils (Olsen 1923 and
others),but here iron availabilitymust also be an importantfactor.This differential
may occur at the root surfaceor at certainsiteswithinthe plant. The very
selectivity
rapid deathof seedlingsof calcifugeplantsin culturescontaininghighlevelsof calcium
as beingsufficient
to accountforcompletefailureso
does not suggestsimpledeficiency
If thereis a largeuptakeof calciumintothe tissue,unlessit is
soon aftergermination.
to an inactivecentreor precipitated
as oxalateit maybringabout inhibition
transported
of enzymeaction. Dixon & Webb (1958) quote considerableevidencebased on in vitro
studiesthatcalciumcan stopthefunctioningof enzymesystemsbecauseit competeswith
othercationssuchas manganeseand magnesium
forco-factorsitesofparticularenzymes.
Origanumvulgarewhen grownat low calcium levels dies fromcalcium deficiency.
However,it seemsunlikelythatcalcicoleplantsrequiremore calciumforgrowth(per
unitweightofprotein)thancalcifugeplants.Analysesofplantswithsimilargrowthhabit,
such as Juncussquarrosusand J. inflexus,
indicatethatthe calciumlevelin thetissuesis
similarin bothplants,althoughone is a calcifugeand the othersomewhatcalcicolous.
for calciumin calcicole
If the mechanismof ion accumulationinvolvesa low affinity
706
of calcium
habit:influence
Calcicole-calcifuge
is also low thenetuptakeofcalcium
plants,thenin soilswherethecalciumconcentration
of thiselementin the plants.
may be smalland resultin deficiency
The precedingdiscussionrelatingto salt uptake is clearlyhypotheticaland several
could be advanced.The aspectsconsideredare, however,very
interpretations
different
Althoughstrictcalcifugesand calcicoleshave
in relationto plantdistribution.
important
narrowlimitsoftoleranceof calciumcontentofthesoils,manyplantshave a fairlywide
in the responseof these
in respectof calciumlevels.Differences
rangeof distribution
concalciumlevelsmaynot be readilyapparentunderexperimental
speciesto different
factorswhich
in soilsare certainly
and availabilityofnutrients
ditions,butconcentration
Here considerableemphasishas been given
requireconsiderationin plantdistribution.
oftheothernutrients
in relationto theconcentration
ofcalciumconcentration
to theeffect
and growthof the speciesstudied,but undoubtedlymanyother
on the establishment
habit.
of thecalcicole-calcifuge
nutritional
factorsare also involvedin determination
SUMMARY
of the establishment
and growthof fournativeBritish
investigation
An experimental
and Origanumvulgare)
species(Juncussquarrosus,Nardusstricta,Sieglingiadecumbens
habit.The plantshavebeen
to thecalcicole-calcifuge
has beencarriedout withreference
conditionsofthe
in cultureswhichprobablyparalleledthenutritional
grownsuccessfully
soils of theirnaturalhabitats.
relative
Particularattentionhas been givento theinfluenceof calciumconcentration
of
the
plants.
on thegrowthand establishment
oftheothernutrients
to theconcentration
were
concentration
responsesofthefourspeciesto calcium
Well markedand distinctive
of
levels
low
and Nardusstrictagrewonlyin culturescontaining
shown.Juncus
squarrosus
of
calcium.
at
Sieglingia
vulgarewas mostvigorous highlevels
calcium,whereasOriganum
on theotherhandwas able to toleratea widerangeof calciumconcentrations.
decumbens
werelow in theculturesolutions,it
Providedthatthelevelsof all ofthemineralnutrients
at
was possibleto growNardusstrictasuccessfully highratiosofcalciumto othercations,
werehigh,even Origanumvulgaredid not thrive
but whenthelevelsof all thenutrients
at thesehighratios.
in the shoottissueof plantsgrownin culturesoluThe amountsof mineralnutrients
valuesobtainedfromplantsofnaturalhabitats.
tionswerecomparedwithcorresponding
conditionsof the culturesverydifferent
Whenpoor growthwas made undernutritional
in the
fromthose of the normalhabitatsof the plants,the levelsof mineralnutrients
naturally.
growing
of
plants
fromthose
different
leaves weresubstantially
and
oftheresultsofthesestudieson thedistribution
The broadecologicalimplications
growthof thefourspeciesare discussed.
REFERENCES
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