全 文 ：广 西 植 物 Guihaia 26(4)：392— 394 2006年 7月
Seasonal variability of facultative
aPom lxlS in A P luda m utica ● ● ● - - ●
MA San—mei ，W ANG Yong—fei1，YE Xiu—lin2
(1．Department of Bioengineering，Jinan University，Guangzhou 510632，China：2．So“th China
BotanicalGarden，theChineseAcademy ofSciences，Guangzhou 510650，China)
Abstract：Variability in incidence of apomictic and sexual embryo sacs was detected in Apluda mutica at Guan—
gzhou City during different seasons in a wild population for two years
． Statistical analysis of incidence of apo—
mictic and sexual embryo sacs indicated significant difference in seasons． Frequencies of apomictic embryo sacs
were the highest in winter and summer respectively in two years
．
Key words：Apluda mutica L．；facuhative apomixis；seasonal variability
CLC number：Q942．5 Document code：A Article ID：1000—3142(2006)04—0392—03
The monotypic genus Apluda belongs to the
sub—family Andropogoninae of Gramineae
． A．mu—
tica L．is a perennial grass． It usually blooms for
three times in June，September，and December re—
spectively during one year in Guangzhou of China
．
However，it tend to bloom rather sporadically in
December． It can stay in bloom for about one
month．It can set seeds twice a year，in July and
October respectively．It set no—seed in December
．
Murty(1973)and Ma et a1．(2002)did the em—
bryological study in A．mutica and found it could
perform facultative apomixis． In facultative apo—
mixis，sexual reproduction promotes genetic varia—
tion，whereas apomixis preserves gene heterozygos—
ity．The production of new genotypes by sexual re—
production could be followed by fecund production
of the best genotypes by apomixis
． Theoretically
facultative apomixis and sexual reproduction form a
well—balanced genetic system． Such a balanced ge—
netic system should enable A．mutica to live in a
variety of environments． Facultative apomixis
could benefit A．mutica in the long run
． But our
knowledge on the occurring frequency of apomictic
frequency in this species is still very limited． The
present study was unde~aken to fill up a part of the
large gap in its variability of apomictic frequency
．
1 Material and methods
Inflorescences of A．mutica was collected from
more than 10 plants at each of five sites in South
China Botanical Garden in June，September and De—
cember respectively． Inflorescences were fixed in
formalin—glacial acetic acid—ethanol(FAA)solution，
and then transferred to 70 alcohol at 4C for
storage．The ovaries were excised from the flowers
with a pair of very fine tip needles，stained in ehrli—
ched hematoxylin，dehydrated through an ethanol
gradient series，and embedded in paraffin
． Serial
sections which were 5—8 m in thickness were cut
and observed under a microscope
． The amount of
ovules observed for each sample varied from 100 to
150．The embryo sacs were classified as sexual or apo—
mictic according to earlier criteria(Ma et a1．，2002)
．
Received date：2005—03—07 Accepted date：2005—09—25
F0岫dation item：Supported by the National Natural Science Foundation of China(3970086)；Ph
． D．Programs Foundation of Jinan
University(692016，692017)
BiograPhy：MA San-mei(1971一)，Female,Born in Henan ProVince,Associate professor，working in teaching and research of Botany
．
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4期 马三梅等：水蔗草兼性无融合生殖的季节变化 393
Proportion of apomictic embryo sac was stud
ied by using analysis of variance．
2 Results
A total 1 1 40 emb~o sacs were colected from
field-growing plants over a 2一year period． Apornictic
frequency was 60．74％，63．92 9／6 and 79．89 respec—
tively in June，September and December for the
year 1 999，and where the apomictic frequency in
winter was significantly higher than those in the
other two seasons(Table 1)．For the year 2000，the
frequency was 75．36 9，6，40．00％ and 35．39 re—
spectively in summer，autumn and winter，where
the apomictic frequency in summer was significant—
ly the highest (Table 1)． M ean percentages of
68．19 9／6 and 50．25 9，6 were classified as being apo—
mictic for all the ovules examined in 1999 and
2000，respectively． There were significantly more
apomictic pistils in the sample collected in June
than those in September and December in 2000．
Statistical analysis of the incidence of apomict—
ic and sexual embryo sacs indicated there were sig—
nificant differences in apomictic frequency in differ—
ent seasons(Table 1)．The dramatic increase in the
proportion of apomictic embryo sac was found in
A．mutica during the winter in 1 999 and summer in
2000． These data suggested that apomictic fre—
quency was not stable in different seasons．
3 Discussion
The percentage of apomictic embryo sac was
significantly different in different seasons
． The
lowest temperature and total precipitation were
2．3C and 58 mm respectively in Guangzhou in De—
cember of 1999．It was found that the frequency of
apomixis was the highest at this time．But the low—
est temperature and total precipitation were 6．9C
and 1 10．5 mm respectively in December of 2000
(Table 1)，the frequency of apomixis was the low—
est at this time． It indicated that the temperature
and precipitation showed no clear association with
the degree of apomixes．
Photoperiod influenced the ratio of apomictic
to sexual sacs in some grasses (Knox，1967)． It
was found that the frequency of apomictic embryo
sac showed the difference in different season in fac—
ultative apomixis Dichanthium aristatum (Knox
1967)．The frequency of apomixes is 59．58 when
the photoperiods are over 1 4 hours，while the photope—
riods are less than 14 hours，it is 90．84 ．Tempera—
ture and precipitation showed no influence to apomictic
frequency in Dichanthium aristatum (Knox 1967)．
Table 1 Comparision of frequency of apomictic
embryo sac in different times
Note：Capital letter indicating significance at 1％ level：Smal let—
ter indicating significance at 5％ leve1．Precipitation and temperature
data obtained from Guangzhou W eather Station．
Flowering and seed setting were retarded
greatly as photoperiod was greater natural photo—
period during inflorescence development(Ma et
口Z．，2003)．It indicated that A．mutica is one of the
short—day plants．M ost short—day plants bloom in
early spring or fal，often requiring fewer than
fourteen hours of light each day．This is also the
case in A．mutica． The frequency of apomixis was
the highest in winter of 1 999 and in summer of
2000 respectively in our study． Inflorescence sam—
pied in December of 1 9 9 9 when effective day—
lengths were less than 1 2 h，had a significant higher
percentage of apomictic pistils than inflorescences
sampled earlier；However，this was not found in
inflorescence taken in December of 2000． Thus。
some factor other than daylength probably was re—
sponsible for the increased proportion of apomictic
pistils in December 1 999． For A．mutica used in
this research，the frequency of apomictic embryo
sacs was not related to changes in temperature，
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394 广 西 植 物 26卷
photoperiods and rainfall when grown in the field．
Otherwise，Hussey et a1．(1991)also found that the
frequency of apomixis was not affected by the pho—
toperiods in Pennisetum ciliate．
The frequency of apomixis had been not easy
to predict，since the photoperiod，temperature，and
rainfall seem no relationship with the apomixis re—
spectively in Guangzhou．Due to the highly irregu—
lar frequency of apomixis that are occasionally ob—
served in field—growing A．mutica，it appears that
environmental factors other than temperature，pho—
toperiods and precipitation or some of them togeth—
er influence the facultative apomixes in A．mutica．
The frequency of apomixis is like the yield of crop，
many environmental cues affected the yield of crop to—
gether，not only one of the environmental cues can de-
termine the frequency of apomixis in A．mutica．
Re：ferences：
Hussey MA，Bashaw EC，Hignight K W ，eta1．1991．Influence of
photoperiod on the frequency of sexual embryo sacs in facuha—
tive apomictic buffelgiass[J]．Euphytica，54：141—145．
Knox RB．1 967．Apomixis：seasonal and population differences
in a grass[J]．Science，157：325—326．
Ma SM(马三梅)，Wang YF(王永飞)，Ye XL(叶秀麟)，et a1．
2003．Influence of photoperiod on facuhative apomixis in
Apludamutica(光照 时间对水 蔗草兼 性无融 合生殖 的影
响)[J]．J Trop Subtrop Bot(热带亚热带植物学报)，ll
(1)：64— 66．
Ma SM(马三梅 )，Ye XL(叶秀麟)，Zhao NX(赵南 先)，et a1．
2002． Embryological studies on facuhative apomixis in
Apludamutica(水蔗草兼性无融合生殖的胚胎学研究)
[J]．Acta Bot Sin(植物学报)，44(3)：259—263．
Murty UR．1 973．Polyploidy and apomixis in Apluda mutica
L．var．aristata(L．)Pilger[J]．Cytologia，38：347——356．
水蔗草兼性无融合生殖的季节变化
马三梅1，王永飞I，叶秀弊2
(1．暨南大学 生物工程学系，广东 广州 510632；2．中国科学院 华南植物园，广东 广州 510650)
摘 要：对广州地区水蔗草在不同季节的无融合生殖胚囊和有性生殖胚囊频率进行了研究。结果表明：无融
合生殖胚囊和有性生殖胚囊的频率在不同季节差异十分显著。两年中，无融合生殖胚囊出现的频率分别在冬
季和夏季最高。
关键词 ：水蔗草；兼性无融合生殖；季节变化
(上接第 380页 Continue from page 380)
Zhang L(张 利)，Zhou YH(周永红)，Wei YM(魏育明)，et
a1．2003c．Relationships among Kengyilia species based on
Random Amplified Microsatelite Polymorphism (RAMP)
(应用 RAMP分子标记探讨仲彬草属的种问关系)[J]．
High Technology Letters(高技术通讯)，13(4)：28—33．
Zhang X Q，Yen C，Yang J L．1 998．Cytogenetic analyses of
Kengyilia laxiflora[J]．Plant Syst Evol，212：79—86．
Zhou YH(周永红)．1994．Study on karyotypes of 5 species of
Kengyilia(仲彬草属5种植物的核型研究)[J]．Guihaia(广
西植物 )，14(2)：163—169．
ZhouYH(周永红)，ZhengYL(郑有 良)，Yang JL(杨俊 良)，eta1．
2000．Relationship among Kengyilia species assessed by RAPD
marker(利用 RAPD分子标记评价仲彬草属的种问关系)[J]．
Acta Phytotax Sin(植物分类学报)，38(6)：515-521．
Zietkiewicz E，Rafalski A，Labuda D． 1994．Genome finger—
printing by simple sequence repeat(SSR)一anchored polymer—
ase chain reaction amplification[J]．Genomics，2O：176—183．
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