植物研究雑誌 J. J. Jpn. Bo t. 66: 66: 160-165 (1991)

On Presumed Hybrid Origin of the Sasaella Makino (B ambusaceae)

a b Mikio WATANABE ，Makoto NISHIDA 組 d Siro KURITA b

aThe aThe Graduate School of Science and Technology ， Chiba University ，1 ・33 ，Yayoi-cho ， Chiba ， 260 JAPAN; bDepartment of Biology ，Faculty of Science ， Chiba University ， 1-33 ，Yayoi-cho ，Chiba ，2ωJAPAN

アズマザサ属の雑種起源の研究

渡辺幹男 a ，西田誠九栗田子郎b

a 千葉大学大学院自然科学研究科 260 千葉市弥生町1-33 ;

b 千葉大学理学部生物学科系統学研究室 260 千葉市弥生町1-33

(Received (Received on June 13 ， 1990)

hypothesis A hypothesis of hybrid origin of Sasaella was tested by morphological comparison. Based on the the flower morphology ，Sasaella ramosa and S. masamuneana were shown to have been derived through

hybridization hybridization between chino and n伊'J) onica or S. palmata.

The gen us Sas αella was established by Makino related' genera in order to exemplify Maekawa's (1929) ，who picked up some species belonging to idea on the origin of Sasaella.

Bα mb ω仏 Sαm 加 d Arundinaril α. Sasaella is characterized characterized by some distinct features such as Materials and Methods fimbriate fimbriate shoulder bristiles and one branch or Localities ， date of sampling and areas of branchlet branchlet per node. However ，Nakai (1 934) in- flowering population of the materials were ob- cluded cluded Sasaella into Arundinal 吻 while Ohwi (1953) served (Table 1). More than fifty inflorescences ， treated treated Sasaella as a member of the genus Sasa. which were randomly collected from each popula- Maekawa (1 960) considered that Sasaella might tion ，have been examined. The morphology of in- been derived through hybridization between Sasa florescences ，spikelets and florets ， the number of and Pleioblastus because of the intermediate stamens in a floret ， the length of anthers and the

appearance appearance of the shoulder ，bristles on the leaf- size and fertility of pollen have been compared. sheath sheath of 8αsα ella. Suzuki (1987) supported The length of the first and the second glumes and Maekawa's opinion in his review of Japanese that of anthers were measured with slide calipers. Bambusaceae. Murata (1977) disagreed with Pollen fertility was estimated by the aceto-orcein 恥1aekawa's opinion and adopted Nakai's staining method and seed fertility of Sasaella systematic systematic treatmen t. ramosa was investigated by sowing 53 fresh seeds In In this paper we observe the floral morphology on wet blotting papers. No seed was obtained from and the fertility of pollen and seeds of Sasaella and Sasaella masamuneana.

-160 ー June June 1991 Journal of Japanese Botany Vo l. 66 No. 3 161

Table Table 1. Materials used for the analysis of floral characters.

Material Material Date of Locality Size of flowering

S国 npling population

Sωα 'eU α S. S. ramosa Makino MAY. '85 ， '86 Okorogawa ， Tochigi 20x40m Pre f.

S. S. ramos αMakino， MAY. '85 ，'86 ， Kurohone ，Gunma Pref. 3x20m ，lO x 15m '87 ， '88 S. S. masamunean α APR. '87 ， '88 Kanazawa Univ. 5x20m Hatusima et Muroi Ishikawa Pre f. Sωα

S.n 伊']J onie α恥iakino MAY. '85 ，'87 ， Oku ・Nikko ， Tochigi 50x 50m '88 '88 Pre f.

S.p α lmata Nakai MAY. '85 ，'87 ， Oku ・Nikko ， Tochigi 5x30m '88 '88 Pref. Pleiobl α'stus P.chino P.chino Makino APR. '85 ，'87 ， Utunomiya Univ. Forest lO x 50m '88 '88 in Funyu ， Tochigi Pref.

Examination and Discussion single spikelet or a terminal verticillaster ， Sasa

1) 1) Morphology of inflorescence n伊']J onica has an axillary panicle. Sasaella ramosa The morphology of inflorescences of 3 genera and S. masamuneana have both a terminal single of of the “ Sasa group" is diagrammatically shown spikelet and an axillary panicle. That is to say ， (Fig. (Fig. 1). Pleioblastus chino has only a terminal Sasaella exhibits an intermediate type of in-

A B C Fig. Fig. 1. Diagrammatic representations of in f1 0rescences of Sasa group; each ellipsoid shows a spikele t. Pleioblastus A: Pleioblastus chino; the spike or verticillaster type. B: B: Sα，saella ramosa and Sasl αella masamuneana; the intermediate types of A and C. C: C: Sasa nipponio α組 d S ，αsa palmat α; the panicle type. 162 162 植物研究雑誌 第 66 巻 第 3 号 平成 3 年 6 月

floresence floresence between Sasa n伊'jJ onica and S. palmata lemma in five speci 回 are drawn σig. 2). As far and Pleioblastus chino. as examined ， Sasa has very short first glume and 2) 2) Pollination mechanism short lemma which are less than 3mm long and

Fundamentally ， the mode of pollination in 6-11mm long respectively. They 紅 e plotted 邸 a “ Sasa group" is so-called neighboring pollination ， concentrated group in the lower-left corner in Fig.

a kind of self-pollination. The st 卸 nens protrude 2. In contrast ，Pleioblastus has longer first glume from a floret ， then hang their anthers and 10-16mm long and lemma 13-18mm long. They dehiscing ，and pollen in such a way that the stigma are plotted in the upper-right corner of Fig. 2. accepts accepts pollen from the upper florets. Wh en the While ，Sasaella has intermediate size ，first glume

wind blows the stigma may have the chan 民 to and lemma are 4-9mm and 9-17mm long ， receive receive pollen from other for hybridization. respectively. 3) 3) Morphology of the spikelet and the floret We tried to compare the length of the first

The size of the first and the second glume ， the glum 邸 with that of the second. However ，we could

ratio ratio betw 悶 1 the lengths of glume and lemma ，and not obtain any definite result distinguishing two that that between the lengths of anther and lemma in taxa of Sasaella as different species.

Gramineae 訂 e importantly effective as diagnostic 4) Morphology of stamens characters characters σateoka ，1959 ， 1975). The number of stamens in florets is exclusively

Length-ratios Length-ratios betw 民 n the first glume and 3 in Pleioblastus ，and 6 in Sas α. No variation in

。Sasaella ramosa frorn Kurohone o Sasaella ramosa from Okorogawa 1214 1214 • Sasaella masamuneana from Kanazawa 富 t:. Sasa nipponica ロ ロ 、回〆 12 • Sasa palmata ロ ω ロPleioblastus chino ロ ロ S ロ ロ ロ 210 QJ) QJ) ...... ， 芝山』戸両 ， 0 ¥ .副司'自司同司・司圃圃-・・・ー 。ィエ 2000¥ 。 o 00 ‘。向。。向、，、In 0 ^_ '" 。 o io 0-0 O 、v ;covoo 。、 。。 030002 。。。¥。 o 00 '-00 OoOv o 血。 。。足。も，、、、:(2 230022f 。、、、 0 ::: 0 -~。 ..， o 0 ，' 、J

。 7 8 9 10 11 12 13 14 15 16 17 18 Lemma (mm) Fig.2. Fig.2. Correlation between first glume length and lemma length. June June 1991 Journal of Japanese Botany Vo l. 66 No. 3 163

A

B

C 。 Relative frequency (cvo) Number of stamens

13 園4 図5 1 6

Fig. Fig. 3. Frequency distribution of the stamen number of Sasaella ramosa and S. masamuneana. A: S. ramosa from Kurohone; B: S. ramosa from Okorogawa; C: S. masamuneana from Kanazawa. The numbers of counted florets in A ，B ，and C are 385 ， 180 and 250 ，respectively.

A 4 咋B

8 I C 。

E

F a -L一

2 3 4 5 6 7 8 Length of an t her (mm)

Fig.4. Fig.4. Variation in anther length (maximum ，minimum ，mean and S.D.) of “Sα sa group" examined. examined. A: Sasa n伊']J onica; B: S. palmata; C: Sas αella ramosa from Kurohone; D: S. ramosa from Okorogawa; E: S. masamuneana from Kanazawa; F: Pleioblastus chino. 164 164 植物研究雑誌第66 巻第3 号 平成 3 年 6 月 number w ぉ examined in either genera. On the Table 2. Pollen stainability. other other hand ， the florets of Sasaella ramosa and S. masamuneana have 3 to 6 stamens σig. 3). Species Mean S.D. The length of anthers in 5 species is shown by a variation diagram σig. 4). Sas αsepcies have Sα3α ell αramosl α 52.34 0/ 0 :t 15.91 Sαsα ella m αsα mune αnα 2.56% :t 2.11 distinctly distinctly shorter 組 thers than those of Pleioblastus

Sasa Sasa n伊'/)onic α， 97.60% :t 0.92 chino chino and the range of sample m 伺 n of these species species is fairly narrow. The range is 3.8 Om m to Sαsαpα 1m αtα 95.76% :t 2.95 4.75mm in S. nipponica ，4.12mm to 5.26mm in Pleioblastus chino 91.09% :t 6.32 S. S. palmata ，and 6.69mm to 7.4 2mm in P. chino. On the other hand ， the length in Sasaella is very variable ， and their range ， were 3.68mm to 6.95mm germinated well within a week under the same in in S. ramosa and 2.4 5mm to 6.13mm in S. conditions. Judging from the results ，we would like mas α， muneana. The degree of variation in Sasaella to support the claim that the species Sasaella was summarized by histograms and its range of originated in an intergeneric hybrid between a sample sample mean with interval estimation was species of Sas αand， Pleioblastus ， as initially calculated calculated within a 95% confidence limit using suggested by Maekawa (1 960). Student's Student's T distribution. 5) 5) Fertility of pollen and seed The first author wishes to thank the late D r. Pollen Pollen fertility of the 5 species of the “Sas α Hiroshi Usui ，D r. Teizo Maeda ， Dr. Mikio group" group" have been estimated by aceto-orcein Kobayashi and D r. Tatsuhiro Ohkubo in Utsuno- stainability. stainability. The results are shown in Table 2. The miya U niversity for their encouragement of the greater greater part of the pollen of Sasa and Pleioblastus study. is is fertile. In contrast ， about the half of the pollen produced produced by Sasaella ramosa is fertile ，and the References fertile fertile pollen 町 e very rare in S. m αsα muneana. Koidzumi G. 1940. Stamens in Arundinaria. Acta Pollen Pollen fertility was also judged by measuring Phytotax. Geobo t. 9:249 (in Japanese). pollen pollen size. Sas αn伊'/)onica and S. palmata and P. 恥1aekawa F. 1960. Evolution is aspec 臼 of the chino chino produce exclusively uniform pollen. inter-generic or inter-specific hybrid. Essays in However the pollen size in Sas αella ram osa and celebration of the centennial anniversary of S. S. mas αmunean αis irregular. The largest pollen Darwinism. pp.115-124 (in Japanese). grain grain is 35μm in diameter and the smallest one Makino T. 1929. A contribution to the knowledge 16μm. This phenomenon suggests that their pollen of the Flora of Japan. J. Jpn. Bo t. 6: are are produced by irregular meiosis. 9-16. Though it is difficult to collect the seeds of the McClure F. A. 1957. Typification of the genera species species of Sasaella ，we procured the seeds of S. of the Bambusoideae. Taxon. 6:199-210. ramosa from one inflorescence. However ， none of Murata G. 1977. Taxonomical notes 13. Acta them germinated within 3 months or more after Phytotax. Geobo t. 30:134-139 (in having having been sown in incubation while seeds of Sas α Japanese). n伊'/)onica and S. palmat αand Pleioblastus chino Nakai T. 1934. Novitates Bambusacearum in June June 1991 Journal of Japanese Botany Vo l. 66 No. 3 165

Imoperio Imoperio J aponico recentissime detectae (I). 要旨 J. J. Jpn. Bo t. 10:547-581. Ohwi J. 1953. Flora of Japan. Shibundo. Tokyo アズ、マザサ属 (8α saell α〉は牧野 (1929) によっ (in (in Japanese). て設立されたが，一方では，Arundin αr のあるい Suzuki Suzuki S. 1978. Index to Japanese Bambusaceae. はササ属 (8αsα) に包含されることもありその GAKKEN ，Tokyo (in Japanese). 分類学的帰属は必ずしも確定してない.その起源 一一一一 1987. New or noteworthy 凶ants of については，前川 (1960) によって雑種説がのべ Japanese Japanese Bambusaceae (5). J. Jpn. Bo t. られ，最近では鈴木(1 987) もその説を支持して 8:274-279. 8:274-279. いるが，アズマザ、サ属植物の雑種性に関する本格

Takagi Takagi T. 1963. On the Spikelets of ，Sasa Pleio ・ 的な検討はされないまま今日に至った.本研究は， blastus blastus and Sasaella. The of reports the Fuji アズマザサ属植物の花に関する形態学的解析を行 garden. 8:58-68 (in Japanese). なうことによってその雑種性を明らかにしようと Tateoka T. 1959. Explanation of Gramineae 試みた.その結果， アズマザ、サ Sα saell αramos α plants. plants. Meibundo. Tokyo (in Japanese). Makino とクリオザサSαsα ella m αsα mune αnα 一一一一 1975. A contribution to the taxonomy of Hatusima et Muroit ま，花形態の特徴(花序，小 the the Agrostis mertensii-flaccida complex 穂・小花の形態)から，ミヤコザ、サ Sαsα nipponic α () (Poaceae) in Japan. Bo t. Mag. Tokyo Makino またはチマキザ、サ Sαsα palm αtαNakai と 88:65-87. 88:65-87. アズマネザ、サ Pleioblastus chino Makino の雑種 一一一1983. Speciation and Taxonomy. Yokendo. Tokyo (in Japanese). であると推定された. Usui Usui H. 196 1. Phytosociological revision of the dominant species of S， α'sa-type undergrowth. Special Special Bulletin of the College of Agriculture Utsunomiya University. 11 (in Japanese)