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植物研究雑誌 1. 1. Jpn. Bo t. 70: 70: 77-84 (1 995) Laboratory Laboratory Culture and Life History of Trichosolen Trichosolen (=Pseudobryopsis) myura (J. Agardh) Taylor from It aly Mitsuo CHIHARA a and Takaaki KOBARA b aTh e Japanese Red Cross College of Nursing ，4・ 1-3 Hiroo ，Shibuya-ku ，Tokyo ， 150 JAPAN; bSenshu bSenshu University ， 2-1-1 Higashi-mita ，Tama-ku ，Kawasaki ，Kanagawa ，214 JAPAN (Received (Received on May 14 ， 1994) Themo 中hology and life history of Trichosolen myura (J. Agardh) Taylor (Syn. Pseudobryopsis myura Berthold) Berthold) are redescribed ，based on material from It aly. Individual thalli are monoecious ，with male and female gametes gametes in separate gametangia. Zygotes produced from gametic fusion develop into prostrate filaments with branches branches and irregularly spaced constrictions. These filaments produce new Trichosolen thalli directly. The life history history ofthe alga 合om Italy is identical with that from Syria (Mayhoub 1974). Herbarium specimens of T. myura collected collected in Japan by Yendo (1 915) have been examined and are reassigned to Bryopsis. Introduction Materials and Methods Trichosolen Trichosolen myura (J. Agardh) Taylor was origi- The specimens used in the present study were nally nally described by J. Ag 征 dh (1842) under the name of collected at Ischia Island near Naples (July 2， 1987) Bryopsis Bryopsis myura ，and was based on specimens col- and at Maria la Scola ，Sicily Island (J uly 8， 1987) in lected lected in Italy. The type locality was not specified and Italy by one ofus ，M. C. They were growing on rocks only only a brief morphological description was given. The several meters below low tide. The specimens for species species was later transferred to Pseudobryopsis morphological observation were preserved in forma- Berthold in Oltmanns (1 904) ，but Trichosolen lin seawater ， while living material for laboratory Montagne (1861) is now recognized as having prior- culture was put into plastic bottles with natural seawater ity ity (Taylor 1962). Feldmann (1937 ， 1969) provided and brought back to the laboratory. The unialgal details details of the morphology and reproduction of T. culture was started from excised apical portions of myura on the basis of the collections at Banyuls on the main axes and ramuli. All cultures were grown in ES Mediterranean Mediterranean coast of France. Mayhoub (1974) has medium (Proyasoli 1966) at 23 0 C and under a light also also studied the life history of T. myura but on speci- regi 11l e of 18h: 611 (l igh t: dark) ， with light intensity of mens collected in Syria. On the basis of these publica- 3，000 -4， 000 lux provided by cool white fluorescent tions tions it appe 訂 s that there is a difference in size of lamps. Under these conditions ， the thalli grew well gametangia between the specimens from France and and produced gametes. The filamentous germlings Syria. Syria. The former has relatively small gametangia. In resultingfrom thezygotes ，九 rere cultured at five differ- this this paper we describe the morphology and life ent temperatures: 15 0 C ，18 0 C ，21 oC ，24 0 C and 2TC. history history of T. myura collected in Italy. Observations of nuclei were made using the fluoro- -:-77- 78 植物研究雑誌第70 巻第2 号 平成 7 年 4 月 chrome DAPI (Coleman 1979). In addition ，speci- the papillum ruptured and gametes were liberated mens in Yendo's collection at the University Mu- through the aperture. Male gametes were liberated as seum ，University of Tokyo (TI) (now deposited in a jet cloud ， as reported in hainanensis Trichosolen the the Hokkaido University Herbarium) were examined. (Kobara and Chihara 1978a). Female gametes were also also liberated rapidly (Fig. 7). When female gametes Observations Observations matured in the gametangia of healthy thalli ， they Morphology swam about immediately after liberation ， without The specimens collected at Ischia Island and Sicily outside staying the gametangium. Sometimes ， the Island Island are similar to each other in their gross mo 叩hol- liberated female gametes stayed as a mass at the tip of ogy. ogy. Thalli are clustered with the numerous main axes gametangium for one or two minutes before swim- originating originating from a common rhizoidal base (Fig. 1). ming away ， as reported by Feldmann (1969) in T. Main axes are up to 120 mm long and 40 0- 1，000μm myura. Male and female gametes possessed two equal wide. wide. Relatively short main axes 紅 e always simple ， anterior flagella. Female gametes were 7-10μmlong but but longer axes are generally branched sub- and 4-5μm wide ， and generally possessed several dichotomously dichotomously or laterally. Axes and branches have green chloroplasts and a red eyespot (Fig. 8). 乱1ale numerous ramuli except on the lower par t. Ramuli are gametes were 4-5μm long and about 2μmwide ， with 2-3 mm long ，2 0-4 0μm wide ，soft ，and arranged one pale green chloroplast and no eye spot (Fig. 9). around around the branches. Gametangia 訂 e ovoid in shape ， When male and female gametes met ，conjugation 100-180μm long and 65-110μm wide ，and each has took place immediately ，resulting in the formation of a papillum at the tip. They are produced adaxially near zygotes (Fig. 10). The zygotes remained motile for the the base of ramuli ，usually singly ， but there 訂 esome- about one hour before attaching to the bottom of the times times two or three per ramulus. Chloroplasts are very culture vessel (Fig. 11). Within three days ， zygotes small ，2-4 μm long and about 2μm wide ， with no increased in volume ， with the formation of a vacuole pyrenoid. pyrenoid. in the cells. After seven days ， they began to germinate (Fig. (Fig. 12). One week later ， the microscopic filament Life Life history produced one to severallateral branches and irregular In In culture ，apical portions grew into erect main constrictions (Fig. 13). After a further six weeks ， the axes axes with ramuli and associated rhizoidal filaments. much branched filamentous germlings were to 5 mm Later ，many erect axes developed from rhizoidal long and 25-50μm in diameter (Figs. 14 ，15). They filaments filaments and those produced ramuli in the upper had a single nucleus ， as already reported by Neumann parts. parts. After about a month ， the cultured thalli had a (1 970) (Fig. 16). The germlings attached on oyster clustered clustered appearance (Fig. 2). Many gametangia were shells and corals did not pene 廿ate the substrates. produced produced adaxially ， near the base of the ramuli (Fig. In orderto examine the possibility of parthenogen- 3). 3). The alga was monoecious. Male and female esis ，male and female gametangia were excised from gametangia gametangia differ from each other in color: male parent thalli and isolated. Unfused male and female gametangia gametangia were light yellowish-green ， while fe- gametes did not develop. males males were dark brownish-green (Fig. 4). Generally After three months growth attemperatures of 21 oc 0 gametangia gametangia of the same sex were produced on single and 24 C ， the prostrate filaments produced erect fila 四 ramuli ramuli (Fig. 5) but rarely the two sexes occurred ments directly (Figs. 17 ，18). These were produced together together (Fig. 6). At the beginning of a light period ， mostly from the terminal ends and were thicker than April April 1995 Jou ll1 al of Japanese Botany Yo l. 70 No. 2 79 Figs. 且-11 ・ 1 n cnosolen myura. 1: Specimen s collected atMaria la Scola ，Sicily Island (July 8， 1987).2: Thallus in culture developed from an apical piece ofaxis or branches ，after 4 weeks. 3: Portion of the thallus ，showing gametangia produced adaxially near the the base of ramuli. 4: Male (I ight yellowish-green) and female gametangia (dark brownish-green) produced on a thallus. 5: two male gametangia (upper) and two female gametangia (1 ower) produced on separate ramuli. 6: Male gametangium (upper) and female female gametangium (I ower) produced on a single ramulus. 7: Female gametangium ，liberating female gametes. 8: Female gametes. gametes. 9: Male gametes. 10: Zygotes. 1 1: Zygotes attached to the substratum. 80 植物研究雑誌第70 巻第2 号 平成 7 年 4 月 • ~ 吋乙~ヘ，---←『田町 一 Figs. Figs. 12-21. Trichoso/en myura. 12: Germinating zygotes. 13: Young germling developed from the zygote ， with branches. 14: Two month old germlings. 15: Two month old germling with several branches and irregular constrictions. 16: Filamentous germling containing containing single nucleus. 17 - 18: Erect filaments developed directly from a filamentous germling . 19: Erect filament containing numerous small nuclei. 20: Erect filament with ramuli. 21 : Typical Trichosolen thallus developed from the filamentous germling. Apri11995 Apri11995 Joumal of Japanese Botany Vo l. 70 No. 2 81 the the prostrate filaments. One to twelve erect filaments filaments. At the higher temperature of 2TC ， only a were produced from each germling. Some of the few erect filaments were produced camong about a protoplasm protoplasm of the prostrate filament appeared to move hundred of filamentous germlings ， but the production into into the erect filaments and ， as a result ，a part of the of gametangia was not depressed. prostrate prostrate filament became pale green or transparen t. At this stage ， both the erect thalli and prostrate fila- Examination of Japanese specimens of Tricho- ment contained numerous small nuclei (Fig. 19). The solen myurafrom the Herbarium ofYendo subsequent subsequent formation of a stephanokont zoospore as In the University Museum ，University of Tokyo reported reported in T. hain α nensis (Kobara and Chihara 1978b; (TI) ， in which Yendo's collection was deposited ，we Okuda et al. 1979) was not observed. The erect found two herbarium 戸pecimens named as Bryopsis filaments filaments grew rapidly and produced many ramuli myura ，a basionym of Trichosolen myura. One of 訂 ound the upper part of the axes (Fig.

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