全 文 ：Development and Age Structure of Ramets of Kalimeris integrifolia
Populations in the Songnen Plains , Northeast China
YANG Yun_Fei＊ , WANG Sheng_Zhong , LI Jian_Dong
(Institute of Grassland Science , Northeast Normal University , Key Laboratory for Vegetation Ecology , Ministry of Education , Changchun 130024 , China)
Abstract: Kalimeris integrifolia Turcz.is a root sucker form perennial herb of Compositae.In the late
period of growing season , fresh fleshy radicels grow up above the soil surface to develop root_borne buds ,
which in turn grow into ramets and taproot.On the basis of observation on numerous samples , methods to clas-
sify the age of ramets and buds for the root sucker herbaceous plant population and to estimate the ages of tap-
roots were established according to their morphology.The age of ramets was classified based on the regeneration
times of taproot buds.Ramets developed from new root sucker buds were classified as 1 a.After 1 a ramets
died , the ramets reproduced from the taproots were 2 a , and so on.New buds from a root sucker were 0 a
buds , other age classes of buds were consistent with that of ramets , i.e.buds produced from taproots of 1 a
ramets were 1 a buds , and so on.In the hay clipping meadows of the Songnen Plains , for K.integrifolia pop-
ulation , there are three age classes of ramets , representing a steady age structure.The maximal age of taproots
of ramets is 4 a.Among all age classes , the population productivity of 2 a ramets was the highest , and that of
1 a ramets was the lowest.The ramet productivity increased with ramet age.During the early period of growing
season , the productivity of 3 a ramets was the highest , but after the middle of growing season , 1 a ramets
showed the greatest relative growth rate.The population size and age structure in the next year could be accu-
rately forecasted by the number of fresh roots with budlet and present population in late autumn.The potential
population in the bud banks was more than two times of the present population , which may provide sufficient
substitution in the future.
Key words: Kalimeris integrifolia;clone;ramet;taproot;bank of bud;age structure;productivity
There are two means of reproduction in higher
plants , one is sexual reproduction by means of flowers and
seeds , and the other is asexual propagation characterized
by ramets developed from vegetative organs.Vigorous
vegetative propagation habit is common in many plants(Cook , 1983;Cain , 1990), but diversity in ramet_gen-
erating organs , degree of independence of ramets on their
parent organs , and the expansibility of the ramets have
been observed(Dong et al , 1999).Perennial plants with
horizontal rhizome are conventionally known as typical
clonal plants(Yang et al ,1998a).Population of a typi-
cal clonal plant is able to continue to increase in size and
space occupied by means of ramet vegetative propagation
even after the ortet died.Therefore , the population is
able to easily thrive in favorable habitats , and some of
them even survive for several centuries ormore(Harberd ,
1961;1962;1963;Oinonen , 1967a;1967b;Vasek ,
1980;Dong , 1996).An important issue is to determine
the age structure of a clonal population , from which rele-
vant information about various aspects of population dy-
namics , such as generation , growth , death , turnover and
productivity of ramets , and even the secrets of population
longevity , can be derived.
Kalimeris integrifolia , a perennial herb of Composi-
tae characterized by one root sucker form(Li , 1978), is
broadly distributed in the northern China , with dense
populations mostly observed in the central_northern part of
northeast China.In the Songnen Plain , it grows common-
ly on meadows , meadow steppes , fixed sand dunes ,
grasslands in the neighborhood of secondary broad_leaved
forests , road sides , and abandoned agricultural fields.
The plants are observed as dominant or sub_dominant
species of communities of different sizes within spatial
vegetation mosaics.Because of excellent palatability , K .
integrifolia is known as a high_quality forage species.
Past studies on this species have been mainly concentrated
on nutrient contents , biological and ecological characteris-
tics(Jia , 1989;Zheng and Li , 1999), and community
structure (Li and Zheng , 1988;1997;Zheng and Li ,
1999).However population structure of the species has
not been reported.Especially the vegetative propagation
characteristics of the species , the longevity of taproots of
ramets , the regeneration of taproots buds , and the growth
and production of ramets , are largely unknown.
On the basis of four times of sampling on populations
of K.integrifolia in a grass clipping field in the Songnen
Plains , we determined the maximal times of bud genera-
tion of taproots under ramets , the age structure of ramets ,
and the productivity of ramets at different ages.The re-
sults revealed interesting characteristics of asexual repro-
duction and propagation of the species in light of its
growth and production strategies , and also laid a basis for
Received:2001-08-30 Accepted:2002-09-20
Supported by the National Natural Science Foundation of China(30070137 ,39770536).
＊Author for correspondence.E_mail:
植 物 学 报
Acta Botanica Sinica 2003 , 45(2):158-163
more deep research on population and communities.
1 Site and Methods
1.1 Sample site
This study was conducted in the Grassland Ecology
Station of Northeast Normal University , located in Provin-
cial Studhorse Farm at Changling County , Jilin Province ,
which geographically belongs to southern Songnen Plain
with temperate semi_arid monsoon climate.
The sampling sites were selected in the places where
K .integrifolia Turcz.was subdominant.The dominant
species in the communities was Leymus chinensis , and the
accompanying species including Calamagrostis epigeios ,
Phragmites communis , Lathyrus quinquenervius , Carex
duriuscula , Artemisia mongolica , Scorzonera albicaulis ,
etc.The K.integrifolia communities , with different spa-
tial extents from 10 m
2
to 1 000 m
2 , were distributed in
scattered patches in the hay_clipping field with the typical
meadow soil.During middle_late period of a growing sea-
son , as growing and top branching of K.integrifolia , the
appearance of the communities shows that the species
gradually becomes dominant.
1.2 Methods
The ramets of K .integrifolia populations in the
studying area were sampled four times on October 2 ,
1999 , and June 15 , July 17 , andAugust 7 , 2000.Each
time , all ramets together with their roots in 6 -10
quadrates measured 50 cm by 50 cm were dug out and
bagged separately for each quadrate.In the laboratory ,
the age class for each ramet in each sampling quadrate
was identified and recorded.The main vertical roots un-
der ramets were cut off.The ramets of each quadrate were
separately oven_dried at the temperature of 80 ℃ until
their weight became virtually constant.
All quantities (number of individuals and weight)
measured within 50 cm by 50 cm quadrates were multi-
plied by a factor of four to give corresponding quantities in
1 m
2.The age spectrums of the quantities of ramets were
statistically determined after percentage of each age class
was calculated for each sampling quadrate.The mean
productivity and growth rate of a specific age class were
computed as averages of the corresponding quantities in
all quadrates.Standard deviations(SD)were also calcu-
lated to give corresponding variations in the data ob-
tained.The formula to calculate difference in average
biomass per ramet between two age classes was
Rab , t=Wb , t-Wa , t
Wa , t ×100% (1)
where Rab , t is the relative difference in average biomass
per ramet between age classes a and b at the t
th
sampling
time , and Wa , t and Wb , t are the average biomass per
ramet in a , t and b , t age classes respectively , also at
the tth sampling time.The absolute and relative growth
rates of a mean individual ramet of age class were calcu-
lated as
GRa , t=Wa , t-Wa , t-1Tt-Tt-1 (2)
RGRa , t=lnWa , t-lnWa , t-1Tt-Tt-1 (3)
where GRa , t and RGRa , t are respectively absolute and
relative growth rates of biomass per ramet in age class a
sampled at the t
th
sampling time Tt , for t=2 ,3 ,4.
2 Results
2.1 Development of ramets and their age classifica-
tion
It was observed that the roots of ramets of K.inte-
grifolia had the following growth characteristics:ramets
had short and straight vertical roots with an evident taproot
section in different age stage that measured 4-8 (10)
cm.Fleshy radicels under the taproot extended horizontal-
ly to all possible directions and crossed with each other to
netting.The first_year radicels appeared milk_white in
color.As their age increased , their color changed gradu-
ally from white to light yellow , and brown.However , the
diameter of these radicels would not increase with age but
stayed in the range of 0.7-1 mm.These radicels , dis-
tributing in the soil layer 10-15 cm deep , had potential
to vegetative propagation.The following process of ramet
development was hypothesized from our observations:after
the seeds became mature during late autumn , some newly
developed fleshy radicels would grow to places 8-12 cm(maximum of 18 cm observed)distant from their parent
plants.The radicels could then grow upward and produce
1-4 buds at 0.3-1 cm above soil surface and then
bend themselves downward with an acute angle to the hor-
izontal root layer again.After the bud emerged , the tap-
roots would grow thick slightly , or become dormant in
winter , or grow up to surface , depending on the micro-
habitat conditions.Generally , in the hay_clipping meadow
grassland area , the buds could continue growing into ram-
ets in August.On the other hand , in the wild meadow
area or roadsides , they were dormant in winter.Although
there were 1-4 buds in one bud area , only one , rarely
two , top bud could continue growing into ramets , sup-
pressing the potential of other buds , and keeping them in
the dormant state.As the aboveground ramets grew , tap-
roots below the ramets also grew thicker.New buds could
continue to emerge around old buds.As a result , every
taproot had a noticeable bud section.The taproot was
gradually lignified as it aged , so that its bud production
potential became lower.After a developed ramet was
damaged during growing season(by insect , or other rea-
sons), or whole plant died after one growing season , an-
other bud could grow up into a new ramet.We have ob-
served that a taproot could produce buds for three ramets
in succession at maximum.
Based on the above discussion , our principle for age
classification of K .integrifolia ramets was the following.
Ramet developed from new root bud was labeled 1 a;the
ramets germinated after the death of 1 a ramets were 2 a;
and so on(Fig.1).It should be noted that if a top ramet
died of insect damage during a growing season , the ramets
germinated during the same growing season would have the
YANG Yun_Fei et al:Development and Age Structure of Ramets of Kalimeris integrifolia Populations in the Songnen Plains 159
same age class as the died ramet.If two ramets germinat-
ed from buds at the same time , they should be classified
as one age class.
The criteria for buds age classification were estab-
lished as follows:buds emerging from fleshy new roots
were 0 a buds , those produced from 1 a taproots of 1 a
ramets were 1 a buds , and so on(Fig.1).The actual age
of a taproot could be derived from the age of its ramets.A
taproot of 1 a ramets developed in the late period of the
previous growing season was two years old.If 2 a ramets
germinated in the end of autumn last year from a 1 a tap-
root and continued to grow this year , the taproot was also
regarded as two years old.If the 2 a ramet was germinated
from 1 a taproots during last spring , the age of the tap-
roots was three years old.Therefore , the age of a 2 a tap-
root was 2-3 years old;and likewise , the age of 3 a tap-
roots was 3-4 years old.
Fig.1. Pattern of age change on ramets and buds in Kalimeris in-
tegrifolia
2.2 Age structure of ramets
The results of investigation and statistics (Table 1)
indicated that , in the hay_clipping meadow field on the
Songnen Plains , the population of K.integrifolia had
three age classes.Among all samples in the three months
of sampling in 2000 , 2 a ramets were the greatest in den-
sity , with on average of(134.8±44.3)ramets/m2 , ac-
counting for 48.0% of the total number;1 a ramets were
in the second place , with an average density of(100.9±
20.1)ramets/m2 , or 36.4% of the total;the smallest
age class was 3 a , with the average of (41.1±14.3)
ramets/m2 , about 15.6%of the total number of ramets.
Hence K.integrifolia was largely a stable population in
the Songnen Plains , according to conventional population
dynamics.
2.3 Productivity per ramet in different age classes
The results of investigation and statistics (Table 2)
on all samples taken respectively in three months indicat-
ed that 2 a ramets had the greatest biomass of(141.5±
85.10)g/m2 , or of 52% of the total ramet biomass;the
average biomass of 1 a ramets was(77.8±45.70)g/m2 ,
about 28.6% of the total;the lowest biomass of(41.5±
15.55)g/m2 was observed for 3 a ramets , which was
19.4%of the total ramets.Thus the data showed that 2 a
ramets had the greatest contribution to the population in
terms of biomass production , but 3 a ramets had the
smallest.The further statistics (Table 3) on average
biomass per ramet showed that 1 a ramet had the smallest
biomass;2 a and 3 a ramets had more and more biomass
in order.Hence the productivity per ramet increased with
Table 1 The number of ramet population and the age spectrum of Kalimeris integrifolia (M±SD)
Month 1 a 2 a 3 a Total
Number of June(n=10) 86.8±30.2 98.0±32.8 57.2±23.2 242.0±42.8
ramets July(n=6) 124.0±32.5 184.0±37.8 30.0±13.1 338.0±64.8
(m2) August(n=7) 92.0±34.0 122.3±33.6 36.0±16.3 250.3±67.7
Mean(n=3) 100.9±20.1 134.8±44.3 41.1±14.3 276.8±53.2
Age spectrum June(n=10) 35.5±8.83 40.2±10.31 24.3±9.54 100
(%) July(n=6) 36.7±8.12 54.7±7.00 8.6±2.24 100
August(n=7) 36.9±8.04 49.1±6.66 14.0±3.16 100
Mean(n=3) 36.4±0.78 48.0±7.29 15.6±7.96 100
Table 2 The biomass of ramet population in Kalimeris integrifolia (M±SD)
Month 1 a 2 a 3 a Total
June (n=8 , g/m2) 25.6±13.94 46.0±18.07 28.0±9.83 99.5±19.58
(%) 29.0±10.37 45.2±13.12 29.8±13.30 100
July (n=6, g/m2) 110.3±32.50 209.1±22.78 38.1±14.03 357.4±38.00
(%) 30.5±7.36 58.8±7.44 10.6±3.71 100
August(n=7 ,g/m2) 97.4±20.98 156.5±31.40 58.5±16.60 325.5±34.80
(%) 30.3±7.53 54.9±5.95 17.7±4.12 100
Mean(n=3, g/m2) 77.8±45.70 141.5±85.10 41.5±15.55 260.8±140.60
(%) 28.6±3.15 52.0±6.82 19.4±9.71 100
160 植物学报 Acta Botanica Sinica Vol.45 No.2 2003
Table 3 The average biomass per ramet in different age classes of Kalimeris integrifolia population((M±SD)g)
Month 1 a 2 a 3 a Mean(n=3)
June(n=8) 0.296 5±1.110 7 0.454 8±0.086 8 0.559 4±0.113 3 0.436 9±0.132 4
July(n=6) 0.889 8±0.142 2 1.182 0±0.294 0 1.370 0±0.650 0 1.147 0±0.242 0
August(n=7) 1.151 0±0.418 0 1.428 8±0.233 8 1.757 0±0.541 0 1.446 0±0.303 0
Mean(n=3) 0.779 0±0.438 0 1.022 0±0.506 0 1.229 0±0.611 0 1.010 0±0.518 0
Table 4 The relative difference in biomass per ramet between dif-
ferent age classes of Kalimeris integrifolia population(Equation 1)
(%)
Month June July August Mean
3 a vs 1 a 88.67 53.97 52.69 57.77
2 a vs 1 a 53.38 32.84 24.14 31.19
3 a vs 2 a 23.00 15.91 22.97 20.25
the ramet age.Table 4 lists relative difference in biomass
between two age classes in different months , and Table 5
gives the absolute and relative growth rates of ramet
biomass in three age classes. Table 4 indicates that from start of the growing sea-
son to 15th of June , 3 a ramet has the highest per_ramet
productivity , which was respectively 88.67% and 23%
Table 5 The absolute and relative growth rates of biomass per ramet of all age classes of the Kalimeris integrifolia population(Equation 2 and
Equation 3)
Time(d)
1 a
GR
(g/ r/ d)
RGR
(g/ g/ d)
2 a
GR
(g/ r/ d)
RGR
(g/g/ d)
3 a
GR
(g/ r/ d)
RGR
(g/ g/ d)
Mean
GR
(g/ r/ d)
RGR
(g/g/ d)
6.15-7.17(32 d) 0.018 5 0.034 3 0.022 7 0.029 8 0.025 3 0.028 0 0.022 2 0.030 2
7.17-8.7(20 d) 0.013 1 0.012 9 0.012 3 0.009 5 0.019 4 0.012 4 0.015 0 0.011 6
6.15-8.7(52 d) 0.016 4 0.026 1 0.018 7 0.022 0 0.023 0 0.022 0 0.019 4 0.023 0
Table 6 The quantitative characters and age structures of present and potential population on Kalimeris integrifolia (n=10)
Min
No./m2 %
Max
No./m2 %
Mean
No./m2 %
SD
No./m2 %
SE
No./m2 %
CV
(%)
Fresh roots with budlet 56.3 206.3 117.5 43.2 13.7 36.8
Buds 0 a 75.0 19.1 362.5 45.2 205.6 35.2 86.3 9.3 27.3 2.9 42.0
1 a 150.0 27.3 400.0 48.5 223.1 39.2 78.2 7.4 24.7 2.3 35.1
2 a 50.0 6.1 193.7 34.9 123.1 22.8 46.8 8.6 14.8 2.7 38.0
3 a 6.3 0.9 25.0 6.1 14.4 2.8 7.3 1.8 2.3 0.6 50.7
Total 393.8 - 825.0 - 566.3 100 136.5 - 43.2 -
Ramets 1 a 75.0 32.4 243.7 73.6 131.9 50.4 55.2 12.9 17.4 4.1 41.8
2 a 31.3 9.4 112.5 40.5 65.6 26.3 24.3 9.1 7.7 2.9 37.0
3 a 25.0 13.2 93.8 34.5 59.4 23.3 21.7 7.2 6.9 2.3 36.5
Total 181.3 - 337.5 - 256.9 100 61.4 - 19.4 - 23.9
higher than those of 1 a and 2 a , and the productivity per
1 a ramet was the lowest.But as the ramet grew , the dif-
ference in per_ramet productivity between 1 a ramets and
2 a , 3 a become smaller , while that between 2 a and 3 a
largely remained unchanged.Table 5 shows that through
the sampling period of time , 3 a ramets has the highest
absolute growing rate , and that 1 a ramets has the highest
relative growing rate with a maximal value of 0.034 3 g/
g/d for the period from the 15th of June to the 17th of Ju-
ly , which was 15.1%and 22.5%higher than those for 2
a ramets(0.029 8 g/g/d)and 3 a ramets(0.028 0 g/g/
d)respectively.The result thus indicated that the rate of
biomass accumulation by 1 a ramets reached its peak dur-
ing the period from middle June to middle July , and grad-
ually slowed down as ramet age increased.Table 5 also
indicates that both the absolute and relative growing rates
of ramets in all age classes decreased with time during a
growing season.
2.4 Quantitative characteristics of clonal bud bank
Table 6 shows that 1 a buds accounted for 39.2%of
the total buds , which was the highest in the bud bank ,
and the portions of 0 a , 2 a , and 3 a buds were 35.2%,
22.8% and 2.8%, respectively.If we regarded ramets
as the present population , and the bud bank as potential
population , the later was more than double of the former.
Based on the criteria for ramet age classification , 0 a , 1 a
and 2 a buds would grow into 1 a , 2 a and 3 a ramets in
the next year , respectively.Comparison between potential
and present population revealed that the number of 0 a
buds from fresh fleshy root was 55.9% more than that
from 1 a ramets , and the numbers of buds germinated
from 1 a and 2 a ramets were respectively 1.7 and 1.9
times of numbers of present 2 a and 3 a ramets.These
facts implied that the taproots of 1 a and 2 a ramets had
vigorous regeneration capability.But only a few of tap-
roots of present 3 a ramets produce buds , accounting for
YANG Yun_Fei et al:Development and Age Structure of Ramets of Kalimeris integrifolia Populations in the Songnen Plains 161
less than 1/5 of present ramets , implying a decreased
trend of regeneration capability with age.Therefore , the
age structure of present population exhibited the charac-
teristics of increasing populations , whereas that of the po-
tential population showed features of stabilized popula-
tions.This is consistent with the results of investigation in
2000.
3 Discussion and Conclusion
3.1 Age structure is a quantification of population dy-
namics.For perennial herbaceous plants in the temperate
grassland , even though clonal populations are usually long
lived , the regeneration capability of any particular ramet ,
such as tillering nodes and rhizomes , is limited.The de-
velopment of ramets of K.integrifolia is characterized by
development of root sucker buds from new_branched fleshy
radicels distant from their parents , which then grow into
the new members of the population in the next growing
season.The fact that development of root sucker buds far
from their parents is highly significant biological and eco-
logical.New_borne ramets from root sucker can reduce
competition for resources with the next generation of their
parents;on the other hand , they can also enlarge the
niche space of the population.The distance of new_borne
root sucker ramets from their parents observed on a hay_
clipping meadow in the Songnen Plains varied from 8 cm
to 12 cm with a maximum of 18 cm.This did not mean
that this distance was the spatial range of the clone expan-
sion , because the fleshy roots connected with new_borne
root sucker could branch to give multiple root suckers.
Further deep studies on the rate of spatial extentsion of
the population were suggested.
3.2 In the hay_clipping meadow in Songnen Plain , the
bud section of taproots of K.integrifolia could develop
ramets three times at most.The age class of a ramet was
determined by the number of generation in bud section of
taproots.The ramets developed from the new_borne root
sucker buds were 1 a ramets.The new root sucker buds
were termed 0 a buds , and so on.The taproots of 1 a
ramets developed in late period of previous growing season
were two years old;those of 2 a ramets were 2-3 years
old;and those of 3 a ramets were 3-4 years old.This
method for determining the age of ramets by generation
number of vegetative reproduction from taproot bud sec-
tion , and quantifying the age of the taproots , was objec-
tive and justified.But the determination of age of buds
was consistent only with the age of ramets , without con-
sidering the length of dormancy of buds.If a new_borne
root can germinate three ramets in the run of three years ,
the root can develop 1-4 buds at the first time , and
some new buds continue to develop , the others may main-
tain dormant during the active period of the root.Further
research is in need in the aspect of the longest years for
the buds remaining dormant of the population.
3.3 For hay_clipping meadows in the Songnen Plains ,
the ramets of K.integrifolia population were in three age
classes of 1 a , 2 a and 3 a.The 2 a ramet was the largest
in number , and 3 a was the smallest.The result thus im-
plied a stable age structure.It has been observed that
more than half of 2 a ramets were developed from the tap-
roots of 1 a ramets during the previous autumn , while
most 3 a ramets were developed from the taproots of 2 a
ramets growing up during the previous autumn after hay
clipping.Thus most taproots of 2 a ramets had the age of
two years old , the same as that of 1 a ramets.Most tap-
roots of 3 a ramets were three years old , rather than four
years old.Identifying the age of ramets based on the
longevity of taproots , we termed 1 a as young stage ,
which accounted on average for 36.4% of all in the sam-
ples taken three times in 2000.If half(24%)of all 2 a(48%)was in the young stage , the taproots in the young
stage would account for 60.4%, while that in elder stage
account for less than 40%.According to such an age
structure of taproots , the population should be classified
as increasing population.The age structure of the popula-
tion implies an important vegetative propagation strategy ,
that is , producing continually new root sucker ramets to
keep them stable or increasing , which can ensure the sus-
tainable regeneration of clone population in suitable envi-
ronment , and expand the niche space of the population.
In fact , small communities of K.integrifolia often show
expanding trends.
3.4 The productivity of 2 a ramets of K .integrifolia
population was the highest , while that of 3 a was the low-
est.Productivity per ramet increased with ramet age.
Comparing the proportions of every age class listed in Ta-
bles 1 and 2 , we found that the biomass of 2 a ramets was
52%, 4% higher than the their number percentage(48%);the biomass of 3 a ramets was 19.4%, and 3.
8%higher than their number percentage (15.6%);but
the biomass of 1 a ramets was 28.6%, 7.8% lower than
their number percentage(36.4%).This fact showed that
the per_ramet productivity of 2 a or 3 a ramets was higher
than that of 1 a ramets.Several studies on gramineous
grasses showed that the tiller productivity of most species
decreased with age(Yang et al , 1995;1998b;Li et al ,
2000;Yang and Zheng , 2000).Here we found that the
ramet productivity of K.integrifolia increased with age.
This might imply that we can increase the population pro-
ductivity by means of hay_clipping to increase the propor-
tion of buds growing into ramets in late autumn so that
more aged members would show up in the next growing
season.
3.5 In the hay_clipping fields in the Songnen Plains ,
during the late growing season , the potential population of
K.integrifolia in clone bud banks represented the steady
type of age structure.But because there were a great
number of the ramets developed from new_borne root
sucker in 1 a ramets , the present population showed the
increasing age structure.Concerning the developing char-
acters of the ramets , most ramets grow as mono_born
form , few of them as twin form or tri_born form.So the
number of new root sucker is generally the number of 1 a
ramets population of next year.If they can all regenerate ,
the number of present 1 a ramets will generally be the
number of 2 a ramets in population of next year , and that
162 植物学报 Acta Botanica Sinica Vol.45 No.2 2003
of present 2 a will generally be that of 3 a ramets.In all
three samples in 2000 , there was no 4 a ramets found.
This means that although 3 a ramets can produce buds ,
the buds lost their ability to grow into ramets.Therefore ,
the fact that potential population is roughly double of the
present population does not mean that the population will
increase rapidly , but mostly serve as sufficient preparation
for the future substitution.
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(Managing editor:HAN Ya_Qin(intern))
松嫩平原全叶马兰种群无性系分株的建成及其年龄结构
杨允菲＊ 王升忠 李建东
(东北师范大学草地研究所 ,植被生态科学教育部重点实验室 , 长春 130024)
摘要: 全叶马兰(Kalimeris integrifolia Turcz.)为根蘖型多年生草本菊科植物。在生长季后期 , 新生肉质细根向地表
生长形成根蘖芽。根蘖芽成株后形成主根。经过对大量样本观察 , 创建了按形态特征对根蘖型草本植物种群无性
系分株和芽的年龄划分方法 ,以及对主根生活年限的估计方法。分株年龄是按主根芽再生的次数划分 , 新根蘖芽
成株为 1 a , 1 a分株死亡后从主根再萌生的分株为 2 a , 2 a分株死亡后从主根再萌生的分株为 3 a。新根蘖芽为 0 a
芽 ,其它龄级与分株的龄级相一致 , 即 1 a分株主根芽为 1 a芽 , 2 a 分株主根芽为 2 a芽。在松嫩平原割草草场 , 全
叶马兰种群由 3个龄级无性系分株组成 , 呈稳定型年龄结构。分株主根的生活年限最多为 4 年。分株的生产力种
群水平以 2 a最高 , 个体水平则以 1 a最低 , 并随着龄级的增加呈增长趋势。其中 ,在生长季初期以 3 a 分株的生产
力最高 ,进入中期以后则 1 a分株的相对生长速率最大。用秋末新生根蘖数量和现时种群数量可以较准确预报翌
年种群数量和年龄结构。芽库中潜在种群数量是现时种群数量的 2 倍以上 , 但不意味着种群将发生疯长 , 而是为
替补所做的充分准备。
关键词: 全叶马兰;无性系;分株;主根;芽库;年龄结构;生产力
中图分类号:Q948.1 文献标识码:A 文章编号:0577-7496(2003)02-0158-06
收稿日期:2001-08-30 接收日期:2002-09-20
基金项目:国家自然科学基金(30070137 ,39770536)。
＊通讯作者。 E_mail:
YANG Yun_Fei et al:Development and Age Structure of Ramets of Kalimeris integrifolia Populations in the Songnen Plains 163