Pollen Morphology of Phylacium (Leguminosae:Papilionoideae)

2005·1.3 MB·English

by  Bin Ye

植物研究雑誌
J. Jpn. Bot.
80: 221-230 (2005)
Pollen Morphology of Phylacium (Leguminosae: Papilionoideae)
Bin YEa and Hiroyoshi OHASHlb
Biological Institute，Gr aduate School of Science，T ohoku University，Se ndai 9808578JAPAN
・
apresent address: Graduate School of Pharmaceutical Science，T ohoku University，Se ndai，9 808578JAPAN
・
E-mail: bye@m引aai日ll.pha訂rm.tωohoku.配a仏C吋j.
bpres詑e飢nltaddress: Botanical Garden，T ohoku University，Se ndai，9 80-0862 JAPAN
E-mail: [email protected]
(Received on February 28，2 005)
Pollen morphology and exine structure of two species of Phylacium in the tribe
Desmodieae were examined. Two samples of P. bracteosum and three samples of P.
mαuus were observed with scanning electron microscopy，a nd each one sample of each
species was observed with transmission electron microscopy. Pollen grains of Phylacium
show variation in the lumina between opposite polar areas. Exine structure shows at hin
and discontinuous tectum，a two-layer infratectum，r educed foot-layer and well-
developed endexine. This complex infratectum structure distinguishes Phylacium from
other members of Desmodieae. Results of the present pollen study agreed with results of
molecular analysis and loment anatomy that indicates Phylacium is not an atural member
of Desmodieae.
Key words: Desmodieae，i nfratectum structure，l umina variation，P hylacium，po llen mor-
phology.
The distinction of Phylacium from other closely related genera， Lespedeza and
genera of the tribe Desmodieae has been Desmodium as selected representative mem-
clarified based on studies pollen mo叩hology bers of Desmodieae.
(Ohashi 1971); on restriction fragment
length polymorphisms (RFLPs) of cpDNA Materials and Methods
data from the principal genera of Pollen materials were obtained from her-
Lespedezinae (Nemoto et al. 1995); on the barium specimens kept in A，B K，B O，I BSC
presence of the rpl2 intron of cpDNA and TUS (Table 1). For SEM observation，
(Bailey et al. 1997) and on the pericp pollen grains were acetolysed following the
訂
structure of the loment (Nemoto and Ohashi standard method (Erdtman 1960) and dehy-
2003). Moreover，a molecular systematic drated in an ethanol series. The samples were
analysis indicates that Phylacium forms a air dried and coated with gold palladium，an d
part of the clade comprising the tribes examined with a Hitachi S-4100 scanning
Phaseoleae and Psoraleeae in the rbcL佐ee electron microscope in the Biological Insti-
(Doyle et al. 2000，K 吋itaet al. 2001). tute，To hoku University. The polar and equa-
This study aims to reconfirm characteristic torial lengths were measured on 20 grains in
features of the pollen grains of Phylacium by each sample. For TEMo bservation，a cetoly-
scanning electron microscopy (SEM) and sed pollen grains were fixed with 2 % os-
transmission electron microscopy (TEM) and mium tetroxide，e mbedded in Spurr low
to compare its pollen mo中hology with viscosity resin. After sectioning with the
-221ー
222 植物研究雑誌第80巻第4号 平成17年8月
Table 1. List of the specimens examined
Species Voucher specimen Locality
Phylacium bracteosum Gillison NGF 22262 (A) Busu，N ew Guinea
Ramas 13052 (BO) Luzon，P hilippines
Phylacium m可us Nanzhidi 4886 (IBSC) Guangxi，C hina
Winit 1551 (BK) Thailand
Tateishi & K司ita69-2 (TUS) Thailand
Lespedeza buergeri Ikestu & Ueno 2086 (TUS) Fukushima，J ap an
Desmodium mult~月orum Koyama & al. T-39666 (TUS) Chiang Mai，T hailand
glass knife，t he sections were stained with or microperforate on pol areawhen asym-
征
uranyl acetate and lead citrate，a nd examined metrical. Exine 2.5-3.5阿nthick in meso
四
with aH itachi H-8100 transmission electron colpium; tectum discontinuous; infratectum
microscope in the Biological institute， comprising two layers in structure，th e upper
Tohoku University (Ye and Ohashi 2002). layer consisting of branchy columellae and
Pollen terminology generally follows Punt dense granules，th e lower layer consisting of
et al. (1994). sp secolumellae; foot-layer thin，d iscon-
紅
tinuous; endexine 1/3-1/2t imes the thick
自
Pollen Morphology of Phylacium ness of exine.
Phylacium has trimorphic pollen grains，
triporate，te 佐aporateand tricolporate (Ohashi Phylacium bracteosum Benn. (Figs. 1-2)
1971). The only known genera in tribe Pollen grains (32.2-)34.5(-36.9)阿nin
Desmodeae with plural pollen types are polar axis; (28.1一)29.8(-31.9)μmin equa-
Alysicαrpus and Phylacium. In the remainder torial diameter; P厄=(1.04-) 1.16(-1.29);
of tribe Desmodieae the pollen grains are colpi short，0 .4-0.6 times the length of polar
mostly uniform and tricolporate (Ohashi axis，b road，c a. 4μm wide at equator，
1971，F erguson and Skvarla 1981). The slightly narrowing to rounded ends，c olpus
Phylacium pollen reported by Ohashi (1971) margins almost undifferentiated from
was based on light microscopy examination mesocolpium; lumina uniform，3- 4μmindi
同
(LM)，b ut in this study it was observed by ameter，or asymmetrical between polar areas，
SEM and TEM. 3-4μm against ca. 1阿nin diameter. Exine
2.5-3.5μm thick in mesocolpium; lower
Phylacium，g eneral pollen features layer of infratectum 1/3-112 times the thick-
Pollen grains tricolporate，ra rely triporate ness of upper layer.
or tetraporate， prolate spheroidal， to
subprolate in shape，e lliptical or subcircular Phylacium majus Coll. & Hemsl. (Figs. 3-
in equatorial view，a lmost circular in polar 5)
view; colpus membrane almost smooth; Pollen grains (26.6-)31.7(-34.4)μm in
endoaperture small to medium，0. 1-0.2 times polar axis; (25.0一)29.7(-33.1)阿nin equato-
the length of polar axis; semitectate; sculp- rial diameter; P厄=(1.00-)1.07(-1.15);
ture in mesocolpium reticulate; lumina 1-4 colpi medium，0 .7-0.8 times the length of
11m in diameter with columellae elements， polar axis，b road，ca . 41 1m wide at equator，
uniform or asymmetrical between the polar narrowing to pointed ends，c olpus margins
eas，sometimes less than 1μm in diameter with ac omplete tectum; lumina asymmetri-
紅
August 2005 Journal of Japanese Botany Vol. 80 No. 4 223
Fig. 1. Pollen grains of Phylacium bracteosum (1). Voucher specimen: Gillison NGF2 2262 (A). A. Equatorial
view showing asymmetrical lumina between two polar areas: coarser reticulate sculpture at upper polar area
and finer reticulate sculpture at lower polar area. Bar =5 μm. B. Reticulate sculpture at mesocolpium.
B =1μm.C，F. Equatorial view showing aperture with short colpus and asymmetrical sculptures between
訂
two poles. Bar =5 μm. D. Polar view showing coarser lumina. Bar =5 凹n.E. Polar view showing finer
lumina. Bar =5 1 1m. G. Cross section. Bar =5 μm. H. Cross section showing thin tectum，t wo layers of
infratectum，di scontinuous thin foot-layer and very thick endexine. Bar =1 μm.
224 植物研究雑誌第80巻第4号 平成17年8月
Fig. 2. Pollen grains of Phylacium bracteosum (2). Voucher specimen: Ramos 13052
(BO). A. Equatorial view showing reticulate sculpture with uniform，al most same
size of lumina between both poles. Bar = 5μm. B. Reticulate sculpture at
mesocolpium. Bar = 1μm. C. Equatorial view showing short colpus with pore.
Bar = 51 1m. D. Polar view. Bar = 5μm.
cal between two polar areas，3 -4μm in di- 1551 (BK)， which is P. majus，n ot P.
ameter in one area，ca . 1μm in diameter or bracteosum. Therefore，P . bracteosum has
less，s ometimes. microperforate in opposite triporate and sometimes tetraporate pollen
area. Exine 2.5-3阿nthick in mesocolpium; grains，w hile P. majus has only tricolporate
lower layer of infratectum 1/4-1/3 times the ones. In this study，h owever，w e found only
thickness of upper layer. tricolporate types in P. bracteosum. The for-
Ohashi (1971) reported that Phylacium mer pollen types were found in as ample
bracteosum has three types of pollen grains， from Canicosa 385 (A)，a s pecimen collected
.ie.，tr iporate or occasionally teaporateand in the Philippines，bu t we did not examine it
佐
tricolporate，b ut the tricolporate record was this time.
eoneousfor this species. The tricolporate Ohashi (1971) reported that the reticulate
町
pollen was sampled from as pecimen，Wi nit sculpture and exine thickness were variable，
August 2005 Journal of Japanese Botany Vol. 80 No. 4 225
Fig. 3. Pollen gr泊nsof Phylacium majus (1). Voucher specimen: Nanzhidi 4886 (IBSC). A. Equatorial view.
B 5f lm. B. Reticulate sculpture at mesocolpium. Bar =1 f lm. C. Equatorial view showing aperture with
訂=
longer colpus (cf. Figs. lC，l F，2 C). Bar =5 f lm. D. Polar view. Bar =5 f lm. E. Section of mesocolpium
showing discontinuous tectum，t wo layers of infratectum，d iscontinuous foot-layer and thick endexine.
Bar= 1μm. F. Equatorial section. Bar =5 μm. G. Section of aperture. Bar =1 μm.
226 植物研究雑誌第80巻第4号 平成17年8月
Fig. 4. Pollen grains of Phylacium mαrjus (2). Voucher specimen: Winit 1551 (BK).
A. Equatorial view showing different lumina between two polar areas: coarser
reticulate sculpture at upper polar area and finer reticulate sculpture at lower
polar ea.Bar=5μm. B. Equatorial view showing aperture and asymmetrical
訂
sculptures between two polar areas. B =5μm.C. Polar view showing coser
紅 訂
lumina. Bar =5 1 1m. D. Polar view showing finer lumina. Bar =5 μm.
but the data shows that the two species diι from New Guinea (Fig. 1) and P. majus from
fer，i. e.，Ph ylacium bracteosum has al umina China (Fig. 3) and Thailand (Figs. 4-5)
5-10凹nin diameter and exine about 5阿n showed notable asymmetry in the sculpture
thick，w hile P. majus has al umina 2-3μmin pattem between the two polar areas; coarse
diameter and the exine about 2伊nthick. In reticulate with lumina 3-4阿nin diameter on
this study，h owever，t he size of the lumina one pole (Figs. lD，4 C) and fine reticulate
sometimes varies or is sometimes uniform in with the lumina ca. 1ド.m(Figs. lE，4 D) in
Phylacium. When it varies，t he variation is diameter or less (Fig. 3D) on the other pole，
observed on each pollen grain，no t on differ- or sometimes only microperforate (Figs. 5A，
ent pollen grains of the same species or diι C-F) which is reduced from reticulate as a
ferent species. Samples of P. bracteosum consequence of closed lumina. One sample
August 2005 Journal of Japanese Botany Vo .l80 No. 4 227
Fig. 5. Pollen grains of Phylacium majus (3). Voucher specimen: Tateishi & Kajita 69-2 (TUS). A，D ，E .
Equatorial view showing different paUern of sculptures between two polar eas:reticulate at upper
訂
apocolpium while sparsely microperforate at lower apocolpium. B =5μm.B. Reticulate sculpture at
訂
mesocolpium. Bar =1 μm. C. Equatorial view showing aperture and asymmetrical sculpture between two
polar areas. Bar =5 μm. F. Polar view showing almost smooth sculpture with sparse microperforations.
Bar= 5μm.
of P. bracteosum from the Phi1ippines (Fig. cially in having wide variability in the pollen
2) has au niform1y reticu1ate scu1pture on types，s cu1pture of the tectum and stratifica-
both p01es with 1umina 3-4μm in diameter. tion of the exine.
The exine thickness is rather uniform be-
tween both species in the samp1es used in Comparative pollen morphology of
，
this study. The pollen grains of P. PhylaciumLespedeza and Desmodium
bracteosum from as pecimen，C anicosa 385 Ferguson and Skvarla (1981) character-
(A)，u sed in Ohashi (1971) needs to be reex- ized the pollen grains of Desmodieae as hav-
amined by SEM and TEM. ing tric01porate apertures and a thick
The pollen grains of Phylacium are hetero- endexine with the 10ss of or av ery thin foot
geneous among the tribe Desmodieae espe- 1ayer. Pollen types are uniform1y tric01porate
228 植物研究雑誌第80巻第4号 平成17年8月
H
Fig. 6. Pollen morphology of Lespedeza buergeri (Figs. A-D. Voucher specimen: Iketsu &U eno 2086，T US)
and Desmodium multiflorum (Figs. E-H. Vouch specimen: H. Koyama & a .lT- 39666，T US). A，E. Polar
view showing microreticulate sculpture. Bar =5 μm. B，F. Section of mesocolpium showing almost equally
thick tectum，i nfratectum and endexine，r egular columellae and consistent foot-layer. Bar =1 11m. C，G .
Section of whole grain. Bar =5 1 1m. D，H. Section of aperture. Note endexine becomes thicker near aperture.
Bar= 1μm.
August 2005 Joumal of Japanese Botany Vo .l80 No. 4 229
in the principal genera of the subtribe their help during this study.
Lespedezinae，i. e.，L espedeza， Campylo-
tropis and Kummerowia， but not in References
Phylacium. Bailey C. D.，D oyle J. J.，K ajita T.，N emoto T. and
We compedexine structures of pollen Ohashi H. 1997. The chloroplast gene rpl2 intron
紅
grains of Phylacium with Lespedeza and and ORF184 as phylogenetic markers in the leg-
ume tribe Desmodieae. Syst. Bot. 22: 133-138.
Desmodium belonging to the subtribe
Doyle J. J.，C happili J. A.， Bailey C. D. and Kajita T.
Desmodiinae. Lespedeza buergeri Miq. and
2000. Towards a comprehensive phylogeny of
Desmodium multiflorum DC. were arbitrarily
Legumes: Evidence from rbcL sequences and non-
selected as representatives of these genera. molecular data. In: Herendeen P. S. and Bruneau
The examination of pollen grains of A. (edsよAdvancesin Legume systematics. pp. 1-
Lespedeza buergeri and Desmodium multi- 20. Royal Botanic Gardens，K ew.
Erdtman G. 1960. The acetolysis method. A revised
florum shows that exine stratifications of
description. Sven. Bot. Tidskr. 54: 561-564.
these species ealmost uniform. They eas
訂 訂 Ferguson I. K. and Skvarla J. J. 1981. The pollen mor-
follows: sculpture microreticulate to reticu- phology of the subfamily Papilionoideae (Legu-
late，e xine 0.8-1.2μm (Fig. 6B-D，F -H) minosae). In: Polhill R. M. and Raven P. H. (eds.).
thick in mesocolpium; tectum is discontinu- Advances in Legume systematics. pp. 859-896.
Royal Botanic Gardens. Kew.
ous (L. buergeri) or almost continuous
Kajita T.，O hashi H.，T ateishi Y.， Bailey C. D. and
(D. multiflorum) in section; infratectum is
Doyle J. 1. 2001. rbcL and legume phylogeny，w ith
regular columellae; foot-layer is thin but
pticularreference to Phaseoleae，Mi llettieae，a nd
訂
continuous，a lmost consistent; endexine is Allies. Syst. Bot. 26: 515-536.
wel1 developed; tectum， infratectum and Nemoto T. and Ohashi H. 2003. Diversity and evolu-
endexine are almost equal in thickness，e ach tion of anatomical structure of loments in tribe
Desmodieae (Papilionoideae). In: Klitgaard B. B.
ca. 1/3 times of the thickness of the exine
and Bruneau A. (eds.)，A dvances in Legume
(Fig. 6).
Systematics. 10. Higher Level Systematics. pp.
The exine of Phylacium (2.5-3.5μmt hick 395-412. Royal Botanic Gardens，K ew.
in mesocolpium) is much thicker than those 一一一，一一一 andTamate H. 1995. Phylogeny on
of L. buergeri and D. multiflorum. The Lespedeza and its allied genera (Desmodieae-
Lespedezinae). In: Crisp加1.and Doyle J. J. (eds.)，
infratectum of Phylacium is much thicker
Advances in Legume Systematics. Part 7.
than the tectum and characterized by the two
Phylogeny. pp. 351-358. Royal Botanic Gardens，
layers as described (see Fig. lG-H，Fi g. 4E- Kew.
G)，w hile that is composed of columellae in Ohashi H. 1971. A taxonomic study of the tribe
Lespedeza and Desmodium. This structure Coronilleae (Leguminosae)，w ith as pecial refer-
differs between Phylacium and the latter two ence to pollen mo中hology.J. Fac. Sci. Univ.
Tokyo，S ec. III，11 : 25-92，pl s. 1-10.
genera，a nd is unique for Phylacium in the
Punt W.，B lackmore S.，Ni lsson S. and Thomas A. Le
tribe Desmodieae.
1994. Glossary of pollen and spore terminology.
Laboratory of Palaeobotany and Palynology，L PP
We gratefully acknowledge the herb紅白 Contributions Series， No. 1， 71 pp. LPP
A，B K，B O and IBSC for providing pollen Foundation，U trecht.
Ye B. and Ohashi H. 2002. Morphology and polymor-
material used in this study. Our sincere
phism in the pollen of Christia and Urariα
thanks to Professors T. Nemoto of
(Leguminosae: Papilionoideae). J. Jpn. Bot 77:
Ishinomaki Senshu University and J. Murata 150-162.
of Botanical Gardens，T okyo University，fo r
230 植物研究雑誌第80巻第4号 平成17年8月
葉 績 ，大橋広好 .マメ科Phylaciumの花粉形
a b
態
Phylacium Benn.はミャンマー，タイ，ラオス， ある.表面の網目模様パターンにも変異があり，
中国南部広西省，フィリピン，インドネシア，パ 構成する網目のサイズが両極間で異なるもの
プア，オーストラリアのクインズランド北部に分 (Figs. lA，C -E; Figs. 3A，C ; Figs. 4A-B; Figs. 5A，
布し， 2種が知られている.子房は 1個だけの脹 C-E) とほとんど同じサイズのもの (Figs.2A，C ，
珠をもち， 1種子の節果をつくることからヌスピ D)がみられる.さらにエキシンの層構造をみる
トハギ連のハギ亜連に分類されている. しかし， と柱状層が構造の異なる 2層に分かれている
花粉形態 (Ohashi1971)，葉緑体遺伝子の制限酵 (Fig. lH; Fig. 3E).エキシンの層構造はヌスピト
素多型 (Nemotoet al. 1995)，塩基配列 (Bailey ハギ連の花粉において重要な特徴であり
et al. 1997)，分子系統学的解析 (Doyleet al. 2000， (Ferguson and Skvarla 1981)， この特徴はキハギ
Kajita et al. 2001) および果皮の解剖学的形態 (Figs. 6B-D) およびDesmodiummultiflorum DC.
(Nemoto and Ohashi 2003) において，Phylacium (Figs. 6F-H)の花粉によく現れていて，エキシン
はハギ亜連を含むヌスピトハギ連と異なることが の柱状層は規則的な形の柱よりなる一層である.
明らかにされている. Phylaciumの花粉はヌスピトハギ連の中で他に見
そこで，本研究ではPhylacium花粉の形態と構 られない複雑な層構造をもっといえる.このよう
造を電子顕微鏡を用いて再調査し，その結果をヌ に，Phylacium花粉の形態と構造は，本属が他の
スピトハギ連の花粉と比較した.便宜上ヌスピト ヌスビトハギ連の属と異なっているとする結果に
ハギ連の代表としてハギ、亜連のハギ属とヌスピト 一致しているものであった.
ノ\ギ亜連のシパハギ、属の花粉を比較した. (東北大学大学院理学研究科生物学教室，
Phylaciumの花粉型には変異があり， 3溝孔粒 現所属.a東北大学大学院薬学研究科，
型， 3孔粒型およぶまれに4孔粒型の3花粉型が 東北大学附属植物園津田記念館)
b