Beni o Valdés, Zoila Diaz Li an e & Raquel Pa a
Nu le p oduc ion and ge nina ion in e nale and he naph odi e
plan s
o
Thymus albicans Ho nanns. & Link (Lamiaceae)
In oduc ion
Abs ac
Valdés,
8.,
Diaz Li an e,
Z.
& Pa a,
R.:
Nu le p oduc ion and ge nina ion
in
emale and he -
maph odi e plan s
o
Thymus albicans Ho manns. & Link (Lamiaceae
).
-Boeeonea
13:
353-
360.2001. -ISSN 1120-4060.
Some ep oduc i e aspec s a e s udied in Thymus albicans Ho manns. & Link, endemie
o
SW
Ibe ian Peninsula. Pe een age
o
he naph odi e plan s ui se , nu le p oduc ion, seed se ,
ep oduc i e e ieiency and pe
c
en age
o
ge nina ion
o
seeds p oduced by emale and he -
maph odi e plan s a e s udied. Pe cen age
o
emale and he naph odi e plan s is e y a iable
be
ween popula ions. Nu le p odue ion and ep odue i e e iciency a
e
highe
in
emale han
in
he naph odi e plan
s,
and his, oge he wi h a sligh ly ad aneed ge nina ion
o
seed p o-.
duced by emales, may ine ease emale i ness
in
na u al popula ions.
Gynodioecy is he occu ence o emale and he naph odi e indi iduals in he same na -
u al popula ions
o
a species.
I
is equen ly he esul
o
he egula occu ence
o
male
s e ile genes in o he wise he naph odi e popula ions (Richa ds 1986). Female plan s can
be conside ed as he naph odi es ha ha e los hei male unc ion, a p ocess in which bo h
nuclea and cy oplasmic genes may be in ol ed (Belhassen & al. 1991).
Gynodioecy can be conside ed a well-s ablished b eeding sys em in he Lamiaceae;
wi hin a popula ion, equencies
o
he naph odi e and emale plan s show li le a ia ion
wi h ime (Richa ds 1986). Models
o
gynodioecy in ol ing he e ec s
o
sel ing pos u-
la e ha emale a e main ained in he popula ion because hei o sp ing a e obliga o y ou -
c ossed and hence mo e i han he p ogeny
o
he naph odi es o en esul ing om sel -
e iliza ion (Cox 1988).
Gynodioecy occu s in mos species
o
Thymus (Mo ales 1986) and has been s udied in
de ail in T ulga is
L.
by Dommee & al. (1978) and Assouad & al. (1978). As in many
o he gynodioecious Angiospe ns (Delph 1996), he co olla in
~male
lowe s is smalle
han
in
he naph odi e lowe s, and while in he la e he e is a well ma ked p o and y,
wi h he s igma becoming ecep i e ou days a e an hesis, in emale lowe s he s igma
is ecep i e inmedia ely a e lowe opening (Mo ales 1986).
Thymus albicans Ho nanns. & Link
is
one
o he
wo Ibe ian Peninsula species
o
sec .
354 Valdés & al.: Nu le p oduc ion and ge mina ion
in
Thymus
Mas ichina
(Mi11e )
Ben ham, cha ac e ized by hei la lea es, which a e ne e cilia e a
he base, and capi uli o m lowe -heads wi h small whi e lowe s wi h cilia e calyx- ee h.
T albicans di e s om he o he species in he sec ion, T mas ichina (L.)
L.
, by he size
o
he calyx, highe
in
T albicans, and size
o
calyx ee h, as long as o sho e han ube
in T mas ichina, bu qui e longe han he ube in T albicans.
I
is
a gynodioecious endan-
ge ed species endemie
o
SW Ibe ian Peninsula whe e i li es in coas al sandy soils
o
a
educed a ea
in
S Po ugal a ound Fa o (Alga e) and in Cadiz p o ince (Spain), whe e i s
dis ibu ion a ea is now in eg esion.
Hs
p esence in Huel a and
Se i11a
p o inces (Mo ales
1986) has no been ecen ly con i med.
The aims
o
his pape
is
o quan i y he sexual ep oduc i e capaci y
o
his species.
Sex dis ibu ion, nu le p oduc ion, ep oduc i e e iciency and seed ge mina ion capaci y
ha e been s udied in se e al popula ions. Possible di e ences be ween emale and he -
maph odi e plan s o hese pa ame e s ha e been checked.
Ma e ia) and Me hods
Fi e popula ions we e chosen nea Chiclana (Oidiz p o ince) (Fig. 1),
a11
li ing on
sandy soils wi h simila clima ic condi ions. Popula ions l, 2 and 3 g ow as pa
o
he
Fig. l. Gene ai dis ibu ion
o
Thymus albicans Ho nanns. & Link. and o igin
o
he popula ions
s udied.
Bocconea
13
-2001 355
open unde sc ub
o
Pinus pinea o es , and popula ions 4 and 5 in open and sunny a eas
a ound he o es .
Pe cen age
o
emale and he map odi e plan s was es ima ed by coun ing ali specimens
in ou popula ions.
F ui se (% l l), nu le p oduc ion, seed se (% S/O) and pe cen age
o
abo ion was
measu ed in se e al emale and he map odi e plan s in he ou popula ions in 1995 and
1996. Plan s
o
simila size, sepa a e o an equi alen dis ance and dis ibu ed a andom
in each popula ion we e chosen. Fi e eplica es
o
50 calyces pe ('lan , ali sepa a e a an-
dom, we e used o e alua e hese pa ame e s. F ui se was es ima ed as pe cen age
o
lowe s which p oduced ui ing calyces, his is, wi h a leas one nu le . Nu le p oduc ion
pe calyx was es ima ed
as
numbe o nu le s p oduced by each ui ing calyx. Seed se was
es ima ed as pe cen age
o
o ules which p oduced nu le s. Pe cen age
o
abo ion e e s o
ali ui ing calyces s udi ed; abo ed e ilized o ules we e ecognizable as seedless nu le s,
which we e always smalle han ipe ones. Rep oduc i e e iciency was measu ed acco d-
ing o Wiens &
al.
(1987) as % S/O x l l.
Pe cen age and dynamic
o
ge mina ion
o
seeds p oduced by emale and he maph o-
di e plan s
o
ou popula ions we e s udi ed in labo a o y condi ions. Fou eplica es
o
each sample,
o 25
nu le s each, we e sown in Oc obe 1995 and Decembe 1996, in s e -
ile Pe i dishes wi h we il e pape . Seeds we e g own in na u al day ligh wi h empe a-
u es anging om
18
o 28°C. Seed ge mina ion was ollowed daily du ing 40 days. The
numbe
o
days elapsed om sowing o ge mina ion
o he
i s seed
( O)
and om sowing
o 50% ge mina ion ( 50) ha e been used
as
indica o s
o
ge mina on dynamic.
Resul s
Pe cen ages
oJ
gynodioecy. -Size
o
popula ion, numbe
o
plan s, densi y and sex dis-
ibu ion in he i e popula ions s udi ed a e indica ed in able
1.
Pe cen age
o
he maph o-
di e and emale plan s is e y a iable om one popula ion o ano he , anging om
39.13% o 63.15% o he maph odi es. In hese pe ennial plan s, no di e ences in sex pe -
cen ages ha e been obse ed in wo consecu i e yea s (1995 and 1996) excep o popu-
la ion
l,
which was pa ially des oyed by building ac i i ies in he sp ing
o
1996.
F uc i ica ion.- F ui se , nu le p oduc ion, seed se , ep oduc i e e iciency (PERS)
and pe cen age
o
abo ion in emale and he maph odi e plan s
o
he ou popula ions
Table l. Densi y and sex dis ibu ion in he popula ion s udi ed.
Popula ion Su ace (m2)
N°
plan s
N°
plan s/m2 % He maph odi e
360
61
0.16 46.
15
2 675
83
0.12 39.13
3 372
95
0.
25
40.47
4 42
19
0.45
63
.
15
5 4234 2032 0.47 62.22
356 Valdés & al.: Nu le p oduc ion and gennina ion in Thymus
Table
2. F uc i ica ion
in
1995
and
1996
in
emale
(F)
and
he maph odi e
(H)
plan s o
he
popula-
ions
1,3,4
and
5.
N,
numbe
o plan s
s udied
.
A) 1995
Popula ion N %
/
l
nu le s/ cal yx
%S
/O PERS %
(mean ± s.d.) abo ion
3-F 3
}'
0.39 4.20 0.38 9.71 1.01 57.63
3-H 4 12.41 7.29 0.60 15.25 1.89 40.46
4-F 4 57.19 16.59 0.65 16.29 9.31 40.68
4-H l 11.36 4.10 0.41 10.40 1.18 58.32
5-F 5 29.34 13.42 0.68 17.24 5.06 38.70
5-H 4
13
.
61
8.13 0.29 7.08 0.96 70.68
B) 1996
Popula ion N % l l nu le s/calyx %S/O PERS %
(mean ± s.d.) abo ion
l - F 4 17.62 5.55 0.48 11.98
2.1/
52.06
l - H 4 10.15 6.86 0.42
10
.
58
1.07 41.03
3-F
9 36.68 10.67 0.64 15.91 5.84 34.60
3
-H
9 20.24 9.58 0.37 9.28 1.88 54.90
5-F
4 14.28 1.42 0.39 9.75 1.39 60.99
5 - H 4 20.78 10.34 0.39 9.82 2.04 54.47
s udi ed in 1995 and 1996 a e indica ed in able
2.
Pe cen ages
o
ui ing calyces wi h
O,
l
and 2 ipe nu le s in emale and hennaph odi e plan s a e shown in Figs. 2a and 2b.
No
s a-
is ical es s ha e been ca ied ou owed o he he e ogenei y in he numbe
o
plan s s ud-
ied
in
each popula ion.
In popula ions l and 4 nu le p oduc ion and ep oduc i e e iciency a e highe in
emale han
ÌÌì'~ennap
h odi e
plan s. In popula ions 3 and 5, whe e hese alues we e es i-
ma ed o wo consecu i e yea s, esul s a e a he con adic o y. In popula ion 3 bo h nu -
le p oduc ion pe ui ing calyx and ui se we e 10we in emale han in hennaph odi e
plan s in 1995, bu conside ably highe in 1996. In popula ion
5,
on he con a y, bo h
pa ame e s we e qui e 'highe in emale han in hennaph odi e plan s in 1995, while hey
we e e y simila in 1996.
As shown in Figs, 2a and 2b, he numbe
o
ipe nu le s pe calyx is a he low, wi h a
educed pe cen age
o
calyces wi h wo ipe nu le s. No calyx was ound wi h h ee o ou
Bocconea
13
-2001 357
ipe nu le s. Numbe
o
nu le s p oduced by ipe calyx ends o. be highe in emale han in
he map odi e plan s.
Seed ge mina ion.- Pe cen age and dynamics
o
ge mina ion
o
seeds o ou popula-
ions s udi ed and le el
o
s a is ic signi ican di e ences o
Iukey
HSD es a e gi en in
able 3.
Ihe e
a e no s a is ically signi ican di e ences be ween popula ions 3 and 4 as
s udi ed in 1995. In 1996 only popula ion 1 showed a pe cen age
o
seed ge mina ion sig-
%
%
10
8
6
4
2
10
O
8
O
6
O
4
O
2
O
3-F 3-H
1-F 1-H
a)
4-F 4-H
b)
3-F 3-H
5-F
5-F
D O nu
~
1 nu
.2
nu
5-H
D
Onu
~ 1
nu
.2
nu
5-H
Fig. 2. Pe cen age
o
ui ing calyces wi h 0, l and 2 nu le s
in
emale (F) and he maph odi e (H)
plan s: a, da a o popula ions 3, 4 and 5 (1995); b, da a o popula ions I, 3 and 5 (1996).

358 Valdés & al.: Nu le p oduc ion and ge mina ion in Thymus
ni ican ly lowe han in popula ions 3 and 5, which did no di e one om he o he . No
di e ences ha e been ound ei he be ween 1995 and 1996
in
popula ion 2.
Da a o emale and he maph odi e plan s
o
hese popula ions a e shown sepa a ely in
able 3. The s a is i c compa ison be ween pai s
o
means in emale e sus he maph odi e
plan s (Mann-Whi ney-U non pa ame i c es ) has shown only signi ican ly di e ences a
he 0.05 le el in popula ion 3 o 1995, bu a he
0.1
le el in popula ion 5 o 1996, wi h
a lowe pe cen age
in
emale e sus he maph odi e plan s.
Da a on dynamics
o
ge mina ion
o
seeds a e also gi en
in
able 3, whe e he pa ame-
e s
O
and 50 ha e been indica ed. Ge mina ion usually begins ea lie
in
nu le s p oduced
by emale han by he maph odi e plan s, bu in popula ions 3 no di e ence was ound in
1996. The pa ame e 50
is
ussually eached
1-3
days ea lie in nu le s p oduced by emales
han in hose p oduced by he maph odi es, bu once mo e popula ion 3 di e s a his
espec .
Table
3.
Pe cen age (%) and dynamics
( O
and 50, in days)
o
ge mina ion
o seeds
in emale (F) and
he maph odi e (H) plan s om popula ions 1,3, 4 and
5.
Mean and s anda d de ia ion (in b acke s)
o % ge mina ion, and mean and ange
o
a ia ion (in b acke s) o
O
and 50, a e indica ed. The
same le e uppe means implies s a is ic di e ences wi h signi icance a le e I as ollows: a= p<
O.OI,
b= p<
O.OOI
[Tukey HSD es ]; x= p< 0.05, y= p<O.1 [Mann-Whi ney-U].
Popula ion yea sex %
O
50 nO eplico
l 1996 F 49.0 (8.9) 3
(2
-5) 7 (4-8) 4
H 44.0 (-) 4 (4) 5 (5) l
To al 48.0 a,b (0.8) 5
3 1995 F 59.0 x (22.2) 3 (3) 4 (4) 4
H 84.0 x (3.3) 3.5 (3-4) 7 (7) 4
To al 71.5 (20.0) 8
1996 F 81.0 (7.6) 3 (3) 4.5 (4-6) 4
H 85.0 (8.2) 3 (3) 4
.2
5 (3-5) 4
To al 82.8 a (7.6) 8
4 1995 F 83.0 (8.9) 3.5 (3-4) 6.2(4-7) 4
H
68
.6 (14.
1)
4 (4) 10.5 (7-14) 2
To al 78.8 (11.6) 6
5 1996 F
78
.0 y (4.0) 2.5 (2-3) 3 (3) 4
H 86.0 y (6.9) 2 (2) 4
(3
-5) 4
To al 82.0 b (16.4) 8
Bocconea
13
-
2001
359
Discussion
The e
is
a wide a iabili y in he uc i ica ion pa ame e s analyzed, which oge he
wi h he di e ences in numbe
o
indi idua1s s udi ed om each popu1a ion comp1ica es
s a is ical compa isons. Howe e , da a sugges ha pe cen age
o
uc i ica ion is e y low
in ali popula ions. Pe cen age
o
au ogamy in he maph odi e plan s is equally e y low, as
i has been obse ed a pe cen age
o
uc i ica ion lowe han 5%, wi h a PERS
o
c.
0.1
(unpublished da a). This indica es he low su i al po enciali y
o
his species.
Seed abo ion, some imes as high as 70%, seems o g ea ly a ec ui se , and he e is
a nega i e co ela ion be ween numbe
o
nu le s pe calyx and deg ee
o
seed abo ion, as
deduced om able
2.
Besides, a high, bu no e alua ed, s yle p eda ion by smallia ae
has been obse ed
in
mos emale and he maph odi e plan s.
Bo hseed
abo ion and s yle
p eda ion could explain he low ui se obse ed, and also he di e ences ound in a pa -
icula popula ion in consecu i e yea s.
On he o he hand he esul s show a gene ai endency o a highe nu le p oduc ion and
ep oduc i e e iciency in emale han
in
he maph odi e plan s, which ag ee wi h he gen-
e ai endency ound in gynodioecious popula ions
o
o he species
o
Thymus (Dommèe &
al. 1978, Assouad & al. 1978), and wi h esul s ound by se e al au ho s
in
o he g oups
(Maki 1993, Eckha 1992).
Seed ge mina ion pe cen age is gene ally high, wi h a o al mean
o
c.
74%. This indi-
ca es ha he e a e no special equi emen s o seed ge mina ion and ha his does no
make any p oblem o he su i al
o
his species. Popula ion l is he only one which sig-
ni ican ly di e s om he o he s by i s low ge mina ion pe cen age, bu no logical expla-
na ion has been ound o his di e ence, as popula ion l is no he smalles and occupies a
simila habi a ha he o he h ee. A he o he side, as deduced om able 3, he e is no
ela ionship be ween pe cen age
o
ge mina ion and sexuali y. Only signi ican di e ences
a e ound in popula ion 3 in 1995, bu no in he same popula ion in 1996.
As indica ed abo e, nu le s p oduced by emale plan s seem o ge mina e ea lie han
hose p oduce by he maph odi es. As ge mina ion occu s a e Au umn ain all, his di -
e ence in ge mina ion may a ou emale o sp ing. Howe e , u he obse a ions could
con i m his endency.
Re e ences
Assouad, M.W., Dommèe, B., Luma e ,
R.
& Valdey on,
G.
1978: Rep oduc i e capaci i
es
in he
sexual o ms
o he
gynodioecious species Thymus ulga is
L.-Bo .
J.
Linn. Soc.
77:
29-39.
Belhassen, E., Dommèe, B., A lan, A., Gouyon,
P.
H
.,
Pomen e, D., Assouad,
M.
W.
& Cou e ,
D.
1991: Complex de e mina ion
o male
s e ili y in Thymus ulga is L.: gene ic and molecula
analysis. -Theo . Appl. Gene . 82: 137-143.
Cox,
P.
A.
1988: Monomo phic and dimo phic sexual s a egies: a modula app oach.- Pp. 80-97
in:
Dous ,
J.
L.
(ed.), Plan ep oduc i e ecology. Pa ems and s a egies. -Ox o d.
Delph,
L.
F.
1996:
Flowe size
dimo phism in plan s wi h unisexual lowe s. -Pp. 217-237
in:
Lloyd,
D.
G.
&
S.
C.
H. Ba e (eds.), Fio ai biology. -New
Yo k.
Dommèe, B., Assouad,
M.
W.
& Valdey on,
G:
1978: Na u al selec ion and gynodioecy in Thymus
ulga is
L.
-Bo .
J.
Linn. Soc. 77: 17-28.
Eckha ,
V.
M.
1992: Resou ce compensa ion and he e olu ion
o
gynodioecy in Phacelia linea is
(Hyd ophyllaceae). -E olu ion 46: 1313-1328.
360 Valdés & al.: Nu le p oduc ion and ge mina ion in Thymus
Maki,
Y.
1993: Ou c ossing and ecundi y ad an age
o
emales in ginodioecious Chionog aphis
japonica
a o
ku ohimensis (Liliaceae). -Am.
J.
Bo . 80: 629-634.
Mo ales, R. 1986: Taxonomia de los géne os Thymus (exc uida la secci6n Se pyllum) y
Th
ymb a en
la Peninsula Ibé ica
..
-Ruizia 3: 1-324.
Richa ds, A. J. 1986: Plan b eeding sys ems. -London.
Wiens, D., Cal in, C. L., Wilson, C. A., Da en, C.
L,
F ank, D. & Sea ey, S. K. 1987: Rep oduc i e
success, spon aneous abo ion, and gene ic load in lowe ing plan s. - Oecologia (Be l.)
71
:
501-782.
Add ess
o
he au ho s:
Valdés, B.,
Dia
z Li an e,
Z.
& Pa a R.: Dp o. Biologia Vege ai y Ecologia, Facul ad
de Biologia, A da. Reina Me cedes sin. Apdo. co eos
1095.41080
Se illa, Spain.