全 文 ：草麻黄雌性生殖器官的个体发生和畸形式样研究
杨 永＊
(中国科学院植物研究所 , 北京 100093)
摘要: 用扫描电镜观察并分析了草麻黄(Ephedra sinica Stapf)雌性生殖器官的个体发生及畸形式样。该种雌球花
个体发生式样与麻黄属其他具双胚珠球果的类群基本一致。外珠被以一对近轴侧突起物出现以及该突起物与苞
片成交互排列的发育式样支持前人关于该构造叶性本质的论述 , 而内珠被与珠心的发育相关 ,因此可能是真正的
珠被 。基于返祖性畸形三胚珠球花的出现及其他形态特征 ,认为麻黄属胚珠数目减少是该属内物种特化的一个趋
势;利用雌球花发育的畸形现象及外珠被的形态学本质提出麻黄属的雌球果为复轴性构造 , 雌性生殖单位是由类
似于科达类的次级生殖枝构造经系统发育变态 、融合 、简化成现存的生胚珠构造式样 ,每一可育苞片及其腋内雌性
生殖单位共同组成了麻黄属的苞鳞_种鳞复合体。
关键词: 麻黄属;雌性生殖单位;个体发生;畸形发育;苞鳞-种鳞复合体
中图分类号:Q941 文献标识码:A 文章编号:0577-7496(2001)10-1011-07
Ontogeny and Metamorphic Patterns of Female Reproductive Organs
of Ephedra sinica Stapf(Ephedraceae)
YANG Yong＊
(Institute of Botany , The Chinese Academy of Sciences , Beijing 100093 , China)
Abstract: Ontogeny and metamorphic development of female reproductive organs in Ephedra sinica Stapf
were surveyed.At the end of April , female cones began to initialize from the vegetative buds.Pollination oc-
curred in mid_May and seeds matured at the beginning of July.The ontogenetic pattern of female reproductive
organs of E.sinica is basically similar to that of E .distachya L.The foliar nature of the outer envelope of the
ovule in Ephedra is corroborated.Reduction of ovule number as a tendency of speciation in the genus is sub-
stantiated by the occurrence of tri_ovulate cones coupled with comprehensive characters of the genus.The
metamorphic patterns as well as the leaf nature of the outer envelope indicate that female cones of Ephedra are
compound while the female reproductive units of the ovulate cone have been reduced from secondary reproduc-
tive shoots similar to those of cordaites by phylogenetic transformation , fusion and reduction.Each fertile bract
together with its axillary female reproductive unit composed the Bract Scale and Seed Scale Complex of
Ephedra.
Key words: Ephedra;female reproductive unit;ontogeny;metamorphic development;bract scale and seed
scale complex
Gnetales (including Ephedra , Gnetum , and Wel-
witschia)has long been considered as the ancestor or sis-
ter group to the ancestor of angiosperms[ 1-7] .However ,
recent studies have suggested that this group is distantly
or even not related to angiosperms while closely related to
conifers , even “gnepine” hypothesis was proposed[ 8-11] .
Since Ephedra is the basal group in the three living gen-
era of Gnetales[ 10 ,11] , detailed knowledge of its characters
is necessary for a better understanding of the phylogenetic
relationships of Gnetales to other seed plants.
The morphological nature of female reproductive or-
gans has contributed greatly to the phylogenetic studies in
gymnosperms[ 12-15] .Though references on female repro-
ductive organs of Ephedra are abundant[ 8 , 16-21] , the
morphological nature of the outer envelope of the ovule as
well as the female reproductive unit(FRU)has been con-
troversial
[ 16 ,21] .
Ephedra sinica belongs to Section Pseudobaccatae of
Ephedra in Ephedraceae and distributes in the north and
northeast of China as well as some limited areas of Mongo-
lia.The species is characteristic of herb_like subshrubs.
Woody stems are short and prostrate , sparsely branched.
Two to three connate leaves insert at nodes;free part of
the leaf is subulate.Male cones are pedunculate in clus-
ters at nodes with four pairs of bracts.Female cones are
terminally or axillarily inserted , usually being solitary or
rarely 2-3 assembled at the top of the branchlets.Each
cone has two ovules and each ovule has a leathery outer
Received:2000-09-13 Accepted:2001-03-19
＊ E_mail address:
植 物 学 报 2001 , 43(10):1011-1017
Acta Botanica Sinica
envelope and a membranous inner envelope.There are
four pairs of bracts , red and fleshy at maturation.Mi-
cropylar tube is straight.There are usually two seeds ,
rarely one , in a mature cone[ 22] .The surface sculpture of
the seed of this species is smooth and closely related to
those of E .distachya , E.intermedia and E.loma-
tolepis.
Three aspects will be determined by investigating the
ontogeny and metamorphic patterns of female reproductive
organs:(1)congruence of the ontogenetic pattern of fe-
male cones between E.sinica and other species with bi_
ovulate cones;(2)the evolutionary trends of ovule num-
ber in female cones;(3)morphological nature of female
cones.
1 Materials and Methods
Materials of Ephedra sinica Stapf for experiment
were collected in Togtoh Xian of Nei Mongol Zizhiqu ,
China.The voucher specimens (NM 99001) are pre-
served in the Herbarium (PE), Institute of Botany , the
Chinese Academy of Sciences.Female cones at various
developmental stages were fixed in formalin_acetic acid_al-
cohol (FAA)from the end of April to the beginning of
May.The fixed ovulate cones were dissected and dehy-
drated in a graded alcohol series , critical_point_dried and
coated with gold palladium.Observation was made by
means of a Hitachi S_800 SEM operating at 30 kV.
2 Results
2.1 Reproductive shoot and female reproductive
unit primordium
Male cones of E.sinica appeared earlier than female
cones.In Togtoh Xian , terminal and axillary young buds
of branchlets began to transform from vegetative growth to
reproductive growth at the end of April.Female cones oc-
curred in the form of axillary or terminal buds (Fig.1)
which are protected by four decussate pairs of bracts.
Apices of the young buds differentiated and gave rise to a
globular female reproductive unit (FRU)primordium to
each axil of the uppermost pair of bracts(Fig.2).Shal-
low grooves came into being between the 2 FRU primordia
(Fig.3), residues of apical buds could be distinguished
at this time.
2.2 Initialization and development of outer envelope
The outer envelope of an ovule made its first appear-
ance as two lateral adaxial protrusions at the base of the
FRU primordium (Fig.4).The initiation complex of the
outer envelope progressed a rapid anisomerous growth to
produce a hippocrepiform structure (Figs.5 , 6);at this
time , the abaxial side of the outer envelope began to
grow.Initials of inner envelope were concomitant.
2.3 Initialization and development of inner envelope
The inner envelope of the ovule came forth as a cir-
cular protrusion between the hippocrepiform outer enve-
lope initiation complex and the inner ovular primordium(Fig.7).The protrusion together with the outer envelope
went on a rapid zonal growth until the two developing en-
velopes surrounded most part of the central globular pri-
mordium (Fig.8)which is the nucellus in nature.During
this phase , the abaxial side of the outer envelope grew
much quicker than the adaxial side while various parts of
the circular initiation complex of the inner envelope grew
concurrently.Soon after the developing inner envelope
surrounded the ovule primordium , the outer envelope grew
slower than the inner envelope.By this way , the top of
the inner envelope stretched out of the outer envelope and
produced a micropylar tube (Figs.9 , 10).The adaxial
side of the inner envelope grew more rapidly than the
abaxial side , which led to the outward orientation of the
opening of the micropylar tube.
2.4 Metamorphic development
Usually , only the apices of the bi_leaved young buds
in E .sinica went to reproductive differentiation , conse-
quently , only the bi_ovulate cones occurred or one FRU
reduced while uni_ovulate cones formed.But in rare cas-
es , apices of the tri_leaved axillary buds(Fig.11)differ-
entiated , and yielded the tri_ovulate cones(Fig.12).
Residues of the apical buds could be distinguished at
the beginning of the initialization of the FRU primordium.
In most cases , the residues did not develop any more , but
we found they went on differentiation and produced a fifth
pair of sterile bracts(Fig.13).
※
Figs.1-17. 1-10.SEM photographs of ovulate structures of Ephedra sinica at successive stages of development.1.Apex with the upper-
most pair of foliar components of the axillary bud , ×300.2.Initiation of ovule primordium to each of the uppermost pair of bracts , ×170.3.
Enlargement of the ovule primordium , ×130.4.Initiation of the outer envelope , note the two adaxial protrusions of ovule primordium ,×150.5.Further development of outer envelope to show the two prominent protrusions of the outer envelope , ×150.6.Initiation of inner
envelope at the inner side of outer envelope as a circular structure surrounding the primordium , ×170.7.Zonal growth of the inner envelope ,×150.8.Further development of the two envelopes to surrounding most part of the ovule primordium , ×200.9.Asymmetrical development
of the inner envelope and formation of micropylar tube , ×60.10.Developed ovule , showing the elongated micropy lar tube and the stomata on
the surface of outer envelope , ×37.11-16.Metamorphic development of ovulate cones of E.sinica.11.Apex with uppermost whorl of
three foliar components of axiallary bud , ×300.12.Occurrence of tri_ovulate cone , ×100.13.Dedifferentiation of the apex and formation
of the fifth pair of bracts subsequent to the occurrence of the female reproductive units , ×170.14.Occurrence of the bud in the axils of one
of the third pair of bracts , ×200.15.Further development of the ovulate structures shown in Fig.14 , ×100.16.Metamorphisms of the two
ovule primordia after the formation of outer envelope to produce two protrusions in one and a complete male reproductive unit in the other ,×130.17.Male reproductive structures.×50.ub , uppermost pair(whorl)of bracts;b , terminal bud;fp , female reproductive unit pri-
mordium;rb , residual terminal bud;ioe , initials of outer envelope;oe , outer envelope;iie , initials of inner envelope;ie , inner envelope;
fru , female reproductive unit;mt , micropylar tube;tb , the third pair of bracts;flp , flattened protrusion;fb , the fifth pair of bracts;bp , the
bifurcate protrusions;m , male reproductive unit.
1012 植 物 学 报 Acta Botanica Sinica 43 卷
10 期 杨 永等:草麻黄雌性生殖器官的个体发生和畸形式样研究(英) 1013
Only the uppermost pair or whorl of bracts of normal
female cones was fertile in all species of Ephedra , but a
third pair of the fertile bracts was found in the present
study consisting of an axillary anterior_posterior flattened
protuberance(Fig.14)and a complete FRU(Fig.15)in-
serted in the axils of the third pair of bracts in two female
cones respectively .
One metamorphic female cone was most interesting ,
in which both of the FRU primordia in the axils of the up-
permost pair of bracts developed the outer envelope , but
did not produce the inner envelope.One of the primordia
differentiated further into two bifurcate projections , while
the primordium in the other FRU yielded a male reproduc-
tive unit(MRU)like structure enclosed within a pair of
bracteoles fused anterior_posteriorly which were decussate
to the protrusions of the outer envelope(Fig.16).
3 Discussion
3.1 Ontogenetic patterns of ovulate structures in E.
sinica
The results indicated that the ontogenetic pattern of
ovulate structures of E .sinica was basically identical to
that of E.distachya[ 16] , which further account for the
consistency of ontogenetic patterns of bi_ovulate cones in
Ephedra , but cases of uni_ovulate and tri_ovulate cones
need to be clarified.
The outer envelope initiated as two protrusions de-
cussate to the uppermost bract pair of the female cones(Fig.4), and the arrangement of the two protrusions is
identical to a basal pair of foliar structures along the sec-
ondary axis.It is also remarkable that stomata are dis-
tributed over the surface of the outer envelope around its
opening (Fig.10).Furthermore , it is strongly suggested
that in the metamorphic patterns(Fig.16)the formation
of the outer envelope is relatively independent to that of
the inner envelope.As a consequence , the author
basically agreed upon Takaso s[ 16] leaf_nature theory that
the outer envelope in E.sinica is transformed from the 2
basal pair of leaves along the secondary axis.However , it
is difficult to determine if the outer envelope complexes of
uni_ovulate cones , bi_ovulate cones , and tri_ovulate cones
in Ephedra are consistently resulted from the fusion of
certain number of leaves only based on the present study.
3.2 Affinities of E.sinica
The arrangement of cones , the quality , number and
fusion degree of bracts , the morphology and number of
seeds , as well as the characteristics of integument tube
are significant to the systematics evaluation of
Ephedra
[ 23-26] .It is suggested that E .sinica may be
closely related to E .distachya and several species with
bi_ovulate cones in Mid_Asia , such as E .ciliata , E.
foliata , E.campylopoda and E .kokanica by the char-
acteristics of ovulate cones occasionally with 2-3 assem-
bled at the top of the branchlets , the straight integument
tube , and the smooth seed surface sculptures.The reduc-
tion of FRU number of ovulate cone in Ephedra correlated
with the specialization of seed surface sculptures.Those
species with specialized seed surface sculptures such as
E.equisetina and E.rhytidosperma often yield uni_ovu-
late cones on account of the reduction of one of the FRUs
in female cones.Pachomova et al[ 23] once suggested a
new taxon in Ephedra , named Section Monospermae
based on similar analysis.The discovery of the reversal
tri_ovulate cones (Fig.12)in E.sinica in the present
study stood for the status of tri_ovulate cone as a probable
ancestral pattern of the bi_ovulate cones , since there was
an evolutionary tendency of reduction in the FRU number
in ovulate cones in Ephedra.According to the above
analysis , female cones of E.lomatolepis probably con-
served more ancestral characters among the living repre-
sentatives of Section Pseudobaccatae in Ephedra , such as
the tri_ovulate cones , cones in clusters , more whorls of
bracts and smooth seed surface sculptures.Female repro-
ductive structures in E .sinica and other species with bi_
ovulate cones may originate from the cone pattern similar
to E.lomatolepis by reduction and specialization of
FRU.
3.3 Morphological nature and evolution of female
reproductive units of Ephedra
Since “ folium in axilla folii” is a morphological im-
possibility , only shoots and its homologous structures can
develop in the axil of foliar organs[ 27] .The anterior_poste-
rior flattened protuberance and the FRU at the third pair
of fertile bracts(Figs.14 , 15)must be homologous to a
shoot structure respectively.The flattened protuberance
may be a bud or a FRU at its early developmental stage.
In E .sinica , there are four pairs of bracts in a normal
female cone , among which only the uppermost pair are
fertile.The reversal development of the fifth pair of sterile
bracts followed the fourth pair of fertile bracts further ac-
counted for the shoot nature of the FRU.This together
with the buds and the FRU developed in the axil of the
third pair of bracts suggested that the extant pattern of the
female cone in Ephedra has been reduced from a com-
pound ovulate cone.A FRU will develop in the axil of
each bract in such cones , which resemble the scenario of
female cones in Welwitschia [ 21] .Both vascular supply and
ontogenetic evidence indicated that the outer envelope of
an ovule in Ephedra is of foliar nature
[ 16 ,19] .As a conse-
quence , a female reproductive unit can be deduced as a
secondary shoot complex structure , but not a simple
ovule. What was most interesting was the fourth type of
metamorphic pattern.Female reproductive units in this
cone gave rise to the outer envelope first , but the inner
envelope did not initiate.Subsequent development pat-
terns between the two FRU could be distinguished.The
primordium in the outer envelope of one of the two FRUs
differentiated into a bifurcate projection , while the tissue
in the outer envelope of the other FRU developed into a
MRU_like structure.The fused pair of bracteoles of the
MRU_like structure was decussate to the two projections of
the outer envelope and anterior_posterior to the cone
bract , which is characteristic of a MRU (Fig.17), we
presumed that this structure is comparable to a true MRU.
The whole teratological pattern clearly demonstrated that
1014 植 物 学 报 Acta Botanica Sinica 43 卷
the primary state of a FRU in Ephedra was a secondary
reproductive shoot , both microsporophylls and megasporo-
phylls attached on this shoot.The fused pair of bracteoles
of a MRU might represent one pair of bracts along the
shoot , but not the proximal pair because of the outer en-
velope positioned lower to the fused bracteoles and devel-
oped earlier than the latter.Moreover , the anterior_poste-
rior arrangement of this pair of bracteoles was coincident
to that of the normal pair of cone bracts but decussate to
the constituents of the outer envelope.This arrangement
further illustrated that the outer envelope might represent
the proximal pair of bracts , while the fused pair of the
bracteoles of the MRU might be the second or fourth pair
of the sterile bracts.This interesting metamorphic pattern
developed neither fertile ovule nor the inner envelope ,
which implied that the inner envelope might closely corre-
late to the fertile ovule in development.Therefore , the in-
ner envelope could be the true integument of the Ephedra
ovule.On the contrary , the outer envelope occurred alone
in the metamorphic cone and might have nothing to do
with the development of the inner envelope or the forma-
tion of a fertile ovule.Furthermore , even in normal cas-
es , the outer envelope surrounded the inner envelopes as
a cupule but not fused to it[ 19] .Hence , it is evident that
the two envelopes of the ovule of Ephedra is inconsistent
in nature.In this metamorphic cone , the ovule primordi-
um in the outer envelope of one of the FRUs differentiated
into two projections , which might represent one of the re-
duced forms in the evolution of the FRU and coincide with
the deductive pattern of ovulate cone evolution from
Eames
[ 8] .
Though forerunners
[ 2 ,12 ,16]
recognized the compound
nature of the female cone of Ephedra , the nature of the
female reproductive unit has not yet been carefully ana-
lyzed.The morphological natures of female reproductive
structures contributed significantly to the phylogeny of
gymnosperms[ 12 ,27 , 28] .The successful explanation of fe-
male reproductive structures in gymnosperms , namely the
Seed Scale Complex theory was advanced by Florin[ 14] and
developed by his adherents.The theory implied that two
basic patterns are involved in the female reproductive or-
gans of extant gymnosperms , which were transformed from
the reproductive shoot.One is represented by cycads(C_
line)in which the megasrobilus is monopodial , with the
fertile leaves and sterile bracts attaching directly on the
main axis.The second line is represented by all the
conifers including Ginkgo , all of which have the structure
of the bract scale and seed scale complex(BS_line).The
members along this line have multipodial female strobili ,
i.e.compound strobili , on the main axis occurred some
sterile vegetative bracts and in the axils of some or most of
the bracts occurred the seed scales.The seed scales are
actually the remains of the extremely , or sometimes com-
pletely reduced fertile shoots.Each part of the bract scale
and seed scale complex and the main axis of the strobilus
could have gone independent or correlated changes , and
thus have had formed various types of strobilus which are
found in the living gymnosperms[ 29 ,30] .According to this
explanation , Ephedra may be one member along the BS
line.The female cones in the genus reduced with only the
uppermost whorl or pair of fertile bracts.Furthermore ,
the FRU did not stand for a simple nature but correspond-
ed to a secondary reproductive shoot , along which the
megasporophylls , microsporophylls as well as the sterile
leaves attached(Fig.18A).The reproductive shoot pre-
served the proximal pair or whorl of leaves which fused in-
to the outer envelope of ovule (Fig.18B)in the phyloge-
netic evolution.The secondary axis and its appendages
experienced the phylogenetic reduction , fusion , transfor-
mation to give rise to the extremely reduced extant forms(Fig.18C-G).In short , the FRU of Ephedra may cor-
respond to the ovulate structures in conifers , each fertile
bract together with its axillary FRU may correspond to the
bract scale and seed scale complex of conifers.In fact ,
the two structures are different in certain aspects.In
conifers , foliar appendages occurred on the top of both the
mature ovulate structures and their earlier ontogenetic
structures(for example , Taxodiaceae).Varied degree of
fusion between the bracts and its related seed scales oc-
curred , such as Araucariaceae , Cuppressaceae ,
Podocarpaceae.However , the FRU in Ephedra preserved
the proximal pair of leaves , and no fusion occurred be-
tween cone bracts and their related FRUs , instead , the
cone bracts preserved the properties of leaf organs.Ac-
cordingly , the bract scale and seed scale complex of
Ephedra may approach the state in Pinaceae in this case.
In fact , the bract scale and seed scale complex of
Ephedra is a kind of distortion of that of conifers , the
shared ancestor of the two groups may be preserved in the
fossils with secondary reproductive shoots from late Paleo-
zoic to early Mesozoic.And both of them may be rooted in
the compound shoot reproductive structures of Cordaitales
in late Carboniferous(Fig.18A).Our new records seem
to provide a morphological support for “gnepines” hypoth-
esis[ 10 ,11] .
3.4 Phylogenetic position of Ephedra
The vessel and the double fertilization in Ephedra
were two critical characters in the phylogeny of seed
plants.Carlquist[ 31 , 32] agreed to Thompson s view-
points[ 33] which maintained that vessels in Ephedra and
angiosperms were parallel after he performed the anatomi-
cal studies of the whole genus.Double fertilization has
long been mistaken as one of the very important evidence
to the relationship between Ephedra and angiosperms.
But the premise of the process was due to the two identi-
cal sperms released into the central cell of an archegonium
in the ovule of Ephedra coupled with the formation of a
ventral canal nucleus and an egg nucleus.Since this
premise existed ubiquitously in the gymnosperms , double
fertilization probably occurred in all members of gym-
nosperms , which has been corroborated by the double fer-
tilization in Abies balsamea , Thuja occidentalis[ 12] as yet.
Accordingly , this phenomenon may be the ancestral state
of all seed plants but not a syapomorphy of Gnetales and
angiosperms
[ 34] .As a conclusion , the vessel and the
double fertilization in Gnetales cannot be considered as
10 期 杨 永等:草麻黄雌性生殖器官的个体发生和畸形式样研究(英) 1015
Fig.18. Evolutionary reduction of the female reproductive unit of Ephedra.
A.Cordaite_like multi_axial ancestral fertile reproductive structures.B.Reduced secondary reproductive shoot with one pair of sterile leaves
and one pair of fertile appendicular structures and the shoot apex.C-G.Further reduction to produce the living reproductive structures.
the evidence for its relationship to angiosperms any
longer.On the contrary , Ephedra shows its affinity to
conifers by the patterns of stomata
[ 35 ,36] , endarch
siphonostele[ 12] , pollen chamber in ovule[ 37] as well as
the FRU evolution.Monophyly of Gnetales was further
corroborated by the recent molecular evidence[ 10 ,11 , 38] .
Winter et al[ 9] concluded that Gnetales was closely relat-
ed to conifers but distantly related to angiosperms as well
as the cycads in light of the sequencing data of the devel-
opment related genes of floral organs.Chaw et al[ 10] ,
Bowe et al[ 11] even tried to support the “Gnetales +
Pinaceae” clade of affinities on account of the multi_ge-
nomic evidence and proposed the “gnepines” hypothesis.
Combined the re_explanation of the morphological nature
of the FRU and its evolution in Ephedra , the affinity of
Gnetales to conifers phylogenetically is indisputable , but
its relationship to Pinaceae need to be further scrutinized.
References:
[ 1 ] Arber N , Parkin J.Studies on the evolution of the an-
giosperms , the relationship of the angiosperms to the Gne-
tales.Ann Bot , 1908 , 22:489-515.[ 2 ] Hickey L J , Taylor D W.Origin of the angiosperm flower.
Tay lor D W , Hickey L J.Flowering Plant Origin , Evolution
and Phy logeny.New York:Chapman &Hall , 1996.176-
231.
[ 3] Friedman W E.Double fertilization in Ephedra , a nonflow-
ering seed plant— its bearing on the origin of angiosperms.
Science , 1990 , 247:951-954.
[ 4 ] Friedman W E.Sexual reproduction in Ephedra nevadensis(Ephedraceae):further evidence of double fertilization in a
non_flowering seed plant.Amer J Bot , 1990 , 77:1582 -
1598.[ 5 ] Friedman W E.Double fertilization in Ephedra trifurca , a
non_flowering seed plant:the relationship between fertiliza-
tion events and the cell cycle.Protoplasma , 1991 , 165:
106-120.[ 6] FriedmanW E.Evidence of a pre_angiosperm origin of en-
dosperm:implications for the evolution of flowering plants.
Science , 1992 , 255:336-339.[ 7 ] Crane P R.Phylogenetic analysis of seed plants and the ori-
gin of angiosperms.Ann MO Bot Gard , 1985 , 72:716 -
793.[ 8] Eames A J.Relationships of the Ephedrales.Phytomor-
phology , 1952 , 2(1):79-100.
[ 9] Winter K U , Becker A , Muenster J , Kim J T , Saedler H ,
Theissen G.MADS_box genes reveal that gnetophytes are
more closely related to conifers than to flowering plants.
Proc Natl Acad Sci USA , 1999 , 96:7342-7347.[ 10] Chaw S H , Christopher L P , Cheng Y C , Vincent T M ,
Palmer J D.Seed plant phylogeny inferred from all three
plant genomes monophyly of extant gymno_sperms and origin
of Gnetales from conifers.Proc Natl Acad Sci USA , 2000 ,
97:4086-4091.[ 11] Bowe M , Coat G , Claude W D.Phylogeny of seed plants
based on all three genomic compartments:extent gymno_
1016 植 物 学 报 Acta Botanica Sinica 43 卷
sperms are monophyletic and Gnetales closest relatives are
conifers.Proc Natl Acad Sci USA , 2000 , 97:4092-4097.
[ 12] Chamberlain C J.Gymnosperms , Structure and Evolution.
Chicago:The University of Chicago Press , 1935.[ 13] Florin R.Evolution in cordaites and conifers.Acta Hort
Bergiani , 1951 , 15:285-388.
[ 14] Florin R.The female reproductive organs of conifers and
taxads.Biol Rev , 1954 , 29:367-389.[ 15] Takaso T , Tomlinson P B.Aspects of cone and ovule on-
togeny in Cryptomeria (Taxoidaceae).Amer J Bot , 1989 ,
76:692-705.[ 16] Takaso T.A developmental study of the integument in gym-
nosperms 3.Ephedra distachya L.and E.equisetina Bge.
Acata Bot Neerl , 1985 , 34(1):33-48.[ 17] Thoday M G , Berridge E M.The anatomy and morphology
of the inflorescences and flowers of Ephedra.Ann Bot ,
1912 , 26:953-985.[ 18] Mehra P N.Occurrence of hermaphrodite flowers and the
development of female gametophyte in Ephedra intermedia.
Ann Bot , 1950 , 14:165-180.
[ 19] Bierhost D W.Morphology of Vascular Plants.New York:
Macmillan , 1971.[ 20] Pearson H H W.Gnetales.London:Cambridge University
Press , 1929.[ 21] Martens P.Les Gnetophytes.Berlin:Borntraeger , 1971.(in French)[ 22] Cheng C_Y(诚静容).Ephedraceae.Cheng W_C(郑万
钧), Fu L_K(傅立国).Flora Reipublicae Popularis Sini-
cae.Vol.7.Beijing:Science Press , 1978.468-489.(in
Chinese)
[ 23] Pachomova M G.Ephedraceae.Glubov V I , Matzenko M
G , Pachomova M G.Plantae Asiae Centralis.Vol.4.
Leningrad:Academia Scientiarum URSS Institutum Botan-
icum Nomine V.L.Komarovii , 1971.25-33.(in Rus-
sian)[ 24] Mussayev L F.On geography and phylogeny of some repre-
sentatives of the genus Ephedra L.Botanical Zhurnal ,
1978 , 63:523-543.(in Russian)[ 25] Meyer C A.Versuch einer Monographie der Gattung
Ephedra.Mem Akad Imper Sci St Petersburg Ser 6 (Sci
Nat), 1846 , 5:225-297.
[ 26] Stapf O.Die Arten der Gattung Ephedra (Monograph).
Denkschr Kaiserl Akad Wiss , Math_Nat Kl , 1889 , 56(2):1-112.
[ 27] Coulter J M , Chamberlain C J.Morphology of Gym-
nosperms.Chicago:The University of Chicago Press ,
1917.[ 28] Meyen S V.Basic features of gymnosperm systematics and
phylogeny as evidenced by the fossil record.Bot Rev ,
1984 , 50:1-111.[ 29] Fu D_Z(傅德志), Yang Q_E(杨亲二).A new morpho-
logical interpretation of the female reproductive organs in
Ginkgo biloba L., with a phylogenetic consideration on
gymnosperms.Acta Phylotax Sin(植物分类学报), 1993 ,
31:294-296.(in Chinese with English abstract)
[ 30] Fu D_Z(傅德志), Yang Q_E(杨亲二).A new morpho-
logical interpretation of the female reproductive organs in
Ginkgo biloba L., with a phylogenetic consideration on
gymno_sperms(Cont.).Acta Phylotax Sinica(植物分类
学报), 1993 , 31:309-317.(in Chinese with English ab-
stract)[ 31] Carlquist S.Wood and bark anatomy of the new world
species of Ephedra .Aliso , 1989 , 12:441-483.[ 32] Carlquist S.Wood , bark and pith anatomy of old world
species of Ephedra and summary for the genus.Aliso ,
1992 , 13:255-295.[ 33] Thompson W P.The anatomy and relationships of the Gne-
tales.Ⅰ .The genus Ephedra.Ann Bot , 1912 , 26:1077-1104.
[ 34] Yang Y (杨永), Fu D_Z (傅德志), Wen L_H (温利
华).On double fertilization in Ephedra.Adv Plant Sci(植
物科学进展), 2000 , 3:67-74.(in Chinese)
[ 35] Inamdar J A , Bhatt D C.Epidermal structure and ontogeny
of stomata in vegetative and reproductive organs of Ephedra
and Gnetum.Ann Bot , 1972 , 36:1041-1046.[ 36] Pant D D , Mehra B.Epidermal structure and development
of stomata in Ephedra foliata Boiss.New Phytologist ,
1964 , 63:91-95.[ 37] Gifford EM , Foster A S.Morphology and Evolution of Vas-
cular Plants.New York:W H Freeman , 1989.[ 38] Stefanoviac S , Jager M , Deutsch J , Broutin J , Masselot M.
Phylogenetic relationships of conifers inferred from partial
28S rRNA gene sequences.Amer J Bot , 1998 , 85:688-
697.
(责任编辑:梁 燕)
10 期 杨 永等:草麻黄雌性生殖器官的个体发生和畸形式样研究(英) 1017