Embryogeny of Sarcandra glabra (Thunb.) Nakai (Chloranthaceae) and Phylogenetic Position of the Chloranthaceae

4 Pages·1998·0.31 MB·English

by  Takasi Yamazaki

植物研究雑誌
J. Jpn. Bot.
73: 22-25 (1998)
Embryogeny of Sarcandra glabra (Thunb.) Nakai (Chloranthaceae)
and Phylogenetic Position of the Chloranthaceae
Takasi YA MAZAKI
akanoku，T okyo，1 65-"J APAN
(Recei ved on September 1，1 997)
The development of embryo of Sarcandra glabra was described. The formation of
embryo had the T-shaped proembryo at the beginning and the initial cells of the root-
cortex were derived from the lowr tier of the cell m，so the embryonic development was
conformed to the Polygonad type. It seems that the Chloranthaceae has closer affinity to
the Polygonales and the Caryophyllales than the Magnoliales.
Engler and Plantl (1894) treated Piperales feature with bracts (the so-called perianths in
(including Chloranthales) as one of the most Hedyosmum，Y amazaki 1992)，s tamens and
primitive order in the Dicotyledons. Rendle carpels are arranged in opposite order as in
(1937) considered that the Piperales (includ- those of Amentiferae. Therefore，th e Piperales
ing Chloranthaceae) were allied to the and the Chrolanthales have less phylogenetic
Polygonales. Recently，m any authors consid- affinity with the Lactoridaceae or the
ered that the Piperales and the Chloranthales Trimeniaceae.
were derived from Magnoliales (Swamy 1953， From the study of rbcL DNA sequences，
Takhtajian 1954，M elchior 1964，C arlquist Chase et al. (1993) treated with Piperales and
1964，Cr onquist 1981 andEndress 1987). Many the Chrolanthales in the Paleoherbs which
of them have considered that，w ithin the were those of the primitive Angiosperms.
Magnoliidae，t he floral morphology of Method of embryonic development reveal
Lactridaceae or Trimeniaceae showed some an important data in the study of the
similar construction with the Piperales and the Angiosperms (Yamazaki 1982). Embryonic
Chloranthales. They were regarded as ag roup development in the Chloranthacea was stud-
with reduced forms of the Magnoliales. ied in Chloranthus serratus Roem. et Schult.
The flower of the Lactridaceae consists of (Yo shida 1959a) and Sarcandra irvingbaileyi
three perianths，si x stamens in two rows and Swamy (Vijayaraghavan 1964)，bu t these re-
three carpels. These floral elements were ar- ports were insufficient to discuss the
ranged with the alternate order and were fun- phylogenetic affinity based on embryonic de-
damentall ya rranged in the reduced form of the velopmen .tThe present work of embryonic
Magnoliaceous flower (Carlquist 1964). In the development on Sarcandra glabrαis an at-
Trimeniaceae stamens are spiral1yi nserted on tempt to contribute to the phylogenetic rela-
receptacle independent of perianths. On the tionships in the Chloranthales.
other hand，th e Piperales and the Chrolanthales
have various floral construction. Nevertheless Materials and Methods
the flowers have the fundamentally common Flowers and fruits were collected from cul-
-22ー
February 1998 Journal of Japanese Botany Vo .l73 No. 1 23
tivated plants in Botanical Gardens，Fa culty of
Science，Un iversity ofTokyo，in July to Octo-
ber，1 994 to 1997. The materials were fixed in
an alcohol-formalin -acetic acid，an d imbedded
in paraffin in the usual way. Serial sections，
12-14μm thick，w ere cut，a nd stained by
Heidenhain' sh ematoxylin and fast green.
Results
Ovule and embryo sac. Ovule is ortho-
tro-pous，b itegmic，a nd crassinucellar，w ith
the micropyle formed by both integuments
(Fig. 1-1). The megaspore mother cells lie in
al inear tetrad，a nd the chalazal one develops
into an embryo sac. These embryosac forma-
tions have been reported by Yo shida (1959b)，
and will not be described in the present paper.
Embryogenesis. The first division of the
fertilized egg is transverse resulting in the
formation of the terminal cell ca and the basal
cell cb (Fig. 2: 1). The cell ca divides verti-
cally，wh ile cb undergoes at ransverse division
producing cells m and ci. The four-celled
proembryo is in T-shaped (Figs. 2: 2，3) . The
terminal cells ca divide vertically to form four
cells. Each of four cells undergoes repeatedly
transverse and vertical divisions to form the
vegetative apex，tw o cotyledons and the upper
part of hypocotyl (Figs. 2: 6-12). In earlier
stages the cell m undergoes vertical divisions
repeatedly (Figs. 2: 4-12) and in many celled
proembryo stages each of these cells under- Fig. 1. 1，tr ansverse section of ovule. e，fe rtilied
goes transverse divisions to form two tiers egg. 2a nd 3，yo ung stages of embryo. Abbrevia-
tions in text. Bar 1= 0. 2 mm. 2a nd 3= 5 0μm.
(Fig. 2: 13). The upper titer of m repeatedly
divides transversely and vertically to form the
lower part of hypocotyl. The lower tier of m 。て
produces the initial of root-cortex (iec) in the ca 山 川2hyp
center (Figs. 2: 14，1 5). The lower cell ci
divides transversely to form na nd s(F igs. 1: 2， C71/2hyp+iec
2: 4). )'he cell ns lowly divides transversely
and vertically to form the [oot cap (Figs. 2: 14，
\
15). The cell ci divides to form the suspensor
(Figs. 2: 13，14 ). s-一一-susp
The recapitulatory table is as follows:
24 植物研究雑誌第73巻第1号 平成10年2月
与:;官専 ，
j、1似合Ir.ii_m_ \ψbl門 l トーγ- IJ 一円、
「t同Lト1ヱGLー?b今÷JθーθよィLィ斗--一ce問En-a一、(cid:631)一(cid:631)(cid:631)一一トlヤ@(@?4@町r9rfe1-H@ θ:;j
1 2 3
4 5
6
-ca ----寸ー『、 ----四--.-..._ 7
8
9
14
50~m
13 15
Fig. 2. Stages of development of embryo. Abbreviations in text.
Abbreviations. pvt，p rovegetative apex. pco， zaki 1982). The embryonic deve10pment of
procotyledon. phy，p rohypocoty .1iec，in itial cells Houttuynia cordata Thunb. in Saururaceae is
of root-cortex. co，ro ot-cap. susp，s uspensor. the same as that of Sarcandra spp (Crete
1957). Crete stated that the embryonic devel-
Discussion
opment of Houttuynia cordαta resemb1es that
The development of embryo of Sarcandra
of the Polygonaceae and the Nyctangiacea.
glabra is fundamentally the same as that of
The Ch10ranthales and the Piperales seem to
S. irvingbailleyi reported by Vijaraghavan
have closer affinity to the Polygonales and the
(1964). He determined that the embryonic Caryophy llales than the恥1agnoliales，in
development of S. irvingbailleyi confirmed which the embryonic development is the
to the Onagrad type by the T- shaped pro- Geraniad type or its variation.
embryo. However，i n the Onagrad type the
initial cells of root-cortex directly derives The author is grateful to Prof.孔1itsuko
from one cell originated from the upper part of Sugiyama，Sa itama Women's Junior College，
tier m. In Sarcandra spp. the initial cells of for her help to this study.
root-cortex were derived from af ew cells
References
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山崎敬:センリョウ(センリョウ科)の匪発生と
センリョウ科の系統学上の位置
センリョウ科はドクダミ科と共に双子葉植物の タデ目やナデシコ目と関係があるものと考えられ
原始的な群として扱われたり モクレン目群から る.近縁とされるLactoridaceaeやTrimeniaceaeでは
の特殊化した群として扱われたりしている.最近 脹形成の詳細な研究はされていないが，花の構造
は主に後者の見解が支持されている.匹形成は科 はセンリョウ科とは基本的に異なるから，モクレ
や目によってほぼ一定していて，系統関係の研究 ン目との関連は考えられない.DNAからの結果と
には重要な手掛かりとなる.今回の観察によりセ は，センリョウ目が原始的であることは一致する
ンリョウの脹形成はPolygonadtypeで， ドクダミ科 が，他の目や科との類縁関係は一致しない.この
のドクダミと同じであることが明らかとなった. 点については今後の研究が必要である.
このことからするとセンリョウ科やドクダミ科は (東京都中野区・・・・・・・)