植物研究雑誌 J. J. Jpn. Bo t. 76: 76: 329-338 (200 1) Variation Variation in Shoot Organization in Prunus (Rosaceae) with with Special Reference to Prunus ogawana c Ak itoshi Iw AMOTO¥ Keiko MIY AZA 阻 b and Jin MURATA aUniversity aUniversity Museum ， the University of Tokyo ， Hongo 7-3-1 ，Bunkyo-ku ，Tokyo ，113 ・0033 JAPAN; bMakino bMakino Herbarium ，Tokyo Metropolitan University ， Minamiosawa 1-1 ，Hachi 吋i，Tokyo ， 192-0397 JAPAN; [Present address: address: [Present Matsubara 3-39-29 ，Setagaya-ku ，Tokyo ， 156-0043 JAPAN] CBotanical CBotanical Gardens ， Graduate School of Science ， the University of Tokyo ， Hakusan 3-7-1 ，Bunkyo-ku ，Tokyo ，112 ・0001 JAPAN (Received on May 11 ，2001) To determine variation in shoot development in Prunus (Rosaceae) ，we observed and and compared the shoot organization of 13 species (9 species of subgen. Cerasus sec t. Pseudocerasus; Pseudocerasus; 1 species of sec t. Microcerasus; 1 species of sec t. Phyllomahaleb; 1 spe- cies cies of Prunus; subgen. and 1 species of subgen. Padus). As a result ，we can categorize the the observed species into four distinct groups based on shoot organization of 1) types of winter winter bud growth ， 2) growth of buds in the axils of scale-like prophylls ， and 3) shoot ab- scission. scission. The first group includes all species of subgen. Cerasus sec t. Pseudocerasus and sec t. Phyllomahaleb except P. ogawana. The second group includes only P. ogawana ， the third third group contains P. mume and P. glandulosa ， and the fourth group contains only P. grayana. grayana. Prunus ogawana (subgen. Cerasus sec t. Pseudocerasus) is distinct from other members of sec t. Pseudocerasus in that some winter buds develop into mixed shoots pro ・ ducing ducing both flowers and leaves ， and some buds in the axils of scall-like prophylls grow into into vegetative shoots. In addition ， this grouping is basically supported by the phylogenetic phylogenetic DNA analysis of Prunus. Key words: Prunus ， Prunus ogawana ， Prunus subgenus Cerasus ， shoot organization Introduction Introduction to determine the degree of variation between Prunus (Rosaceae) ， comprising about 200 them. We especially focused on P. ogawana species ， has been usually classified into sev- Makino (subgen. Cerasus sec t. Pseudocera- eral eral subgenera (Rehder 1940 ，Gohra and sus). The species usually blossoms within Panigrahi Panigrahi 1995). Ohba (1989) recognized three ye 訂 s of germination (Makino 1906) ， five five subgenera (Prunus ，Amygdalus ，Padus ， while other species of Prunus usually need Laurocerasus ， Cerasus) in J apan. There are 10-15 years for flowering. Additionally ， the some references to shoot organization in species produces fertile seeds that can rela- Prunus in the descriptions of the species ， but tively easily propagate. Hence ， Prunus critical critical comparative studies have not been ogawana was expected to be suitable for ex- conducted. conducted. We observed the shoot organiza 四 perimental studies of flower formation in tion tion of species of 13 Prunus (mainly Prunus using genetic recombinant methoas. J apanese wild species) to comp 訂 e them and Flowering at a juvenile stage has been -329 ー 330 植物研究雑誌 第76 巻 第6号 平成13 年12 月 considered considered to be the only distinct characteris- subgen. Cerasus sec t. Phyllomahaleb (P. tic tic differentiating it from other species of maximowiczii). Th e materials used in this sec t. Pseudocerasus. Our preliminary obser- study 訂 e shown in Table 1. We observed de- vations vations revealed that all winter buds develop tails of the shoots macrographically. A into into shoots with flowers. This feature does stereoscopic microscope was used to observe not not occur in other species of Prunus and axillary bud organization. shows shows that the shoot organization of P. ogaw αna may be unique. Detailed observa- Results tions tions of shoot organization in P. ogawana F eatures observed and and of other phylogenetically closely related We determined that 伽 ee features were species species of Prunus 紅 'e necess 紅 Y to ascertain important for analyzing shoot organization; that that the feature is species-specific. (1) type of winter bud growth ， (2) growth of buds buds in the axils of scale-like prophylls and Materials Materials and Methods (3) shoot abscission. Observations of each We observed shoots of 13 species of item 紅 e as follows: Prunus throughout two years (from April 1998 1998 to March 2000) using living trees and (1) Types of winter bud growth sample sample branches obtained from the 佐ees. All the species examined in this study 訂 e Among 13 species ， nine belong to subgenus deciduous and all new shoots extend from Cerasus Cerasus sec t. Pseudocerasus ， the other four winter buds. The winter buds of species of belong belong to: subgen. Prunus (P. mume) ， Prunus usually develop into one of three subgen. subgen. Padus (P. grayana) ，subgen. Cerasus types: (1) a vegetative shoot that produces sec t. Microcerasus (P. glandulos α) and some leaves and no flowers ， (2) a reproduc- Table Table 1. Observed materials of Prunus s. 1. in this study. Scientific names 訂 e 紅 ranged according to Ohba (1 989) Subgenus Subgenus Section Species Source* Cerasus Cerasus Phyllomahaleb maximowiczii Rupr. IV wwwwwwww Pseudocerasus Pseudocerasus apetala (Siebold & Zucc.) Franch. & Sav. cerasoides cerasoides D. Don v訂 . campanulata (Maxim.) Koidz. incisa incisa Thunb. YEAYE-TEly-- jamasakura Siebold ex Koidz. 11 111 pendula pendula Maxim. f. ascendens (Makino) Ohwi sargentii sargentii Rehder speciosa speciosa (Koidz.) Nakai verecundi α(Koidz.) Koehne 111 ogawana Makino 11 Microcerasus Microcerasus glandulosa Thunb. IV Prunus Prunus mume (Siebold) Siebold & Zucc. IV Padus Padus grayana Maxim. IV Source. * Source. 1: Tokyo Metropolitan University. 11: Botanical Gardens Koishikawa ， Graduate School of Science ， the University of Tokyo. 111: Botanical Gardens Nikko ， Graduate School of Science ， the University University of Tokyo. IV: Tama Forest Science Garden. December December 2001 Joumal of Japanese Botany Vo l. 76 No. 6 331 F -p reproductive reproductive shoot reproductive reproductive shoot (a) (a) (b) vegetative vegetative shoot vegetative shoot (c) (c) (d) Fig. Fig. 1. Types of winter bud growth in Prunus s. 1. (a) Winter buds grow into both reproduc- tive tive shoots and vegetative shoots. (b) All winter buds grow into shoots with flowers. Some shoots also develop leaves (mixed shoots). (c) Winter buds grow into only vege- tative tative shoots. (d) All winter buds grow into shoots with leaves. F: flower. B: brac t. L: lea f. S: scale-like leaf. P: scale-like prophylls of winter buds. Arrows indicate indefinite shoots. shoots. 332 植物研究雑誌第76 巻第6号 平成 13 年12 月 tive tive shoot that produce some flowers and no (c) Growth into only vegetative shoots leaves leaves or (3) a mixed shoot that produce both All winter buds grow into vegetative flowers flowers and leaves. We also found that the shoots in this type and no shoots with flow- species species of Prunus produce three kinds of ers were found. Buds in the axils of scale 田 winter winter buds in various combinations ， which like prophylls also show shoot elongation of are are illustrated in Fig. 1. another type (see (2) Growth of buds in the (a) (a) Growth into reproductive shoots and axil of scale-like prophylls). The species vegetative vegetative shoots which show this type are P. mume and P. Winter Winter buds produce a reproductive shoot glandulosa. and and a vegetative shoot in this type. No buds (d) Growth into vegetative shoots and develop develop into a mixed shoo t. An apical bud is mixed shoots more likely than a lateral one to grow into a All winter buds develop leaves and some- vegetative vegetative shoo t. The species that show this times also produce some flowers. The spe- type type are P. jam αsakura ， P. verecunda ， P. cies showing this type is P. grayana. sargentii ， P. speciosa ， P. pendula ， P. cerasoides ， P. incisa ， P. apelata and P. (2) Growth of buds in the axils of scale-like maxzmowzcZll. maxzmowzcZll. prophylls (b) (b) Growth into reproductive shoots and Some species of Prunus have buds in the mixed shoots axils of scale-like prophylls of the winter All All winter buds produce flowers. In addi- buds (we call the bud in the axil of a leaf the tion ，some of them also develop some leaves ， main bud to distinguish it from the buds in but but buds in the axils of scale-like prophyll the axils of scale 田 like prophylls) (Fig. 2). show shoot elongation of another type (see The prophyll buds do not appear to expand (2) (2) Growth of buds in the axil of scale-like soon ， but a study by Guo et al. (1992) im- prophylls). prophylls). The species showing this type is plied that such buds in P. persica regul 紅 ly P.ogawana. develop into shoots. Our observations re- vealed vealed that the axillary buds show a variety Aowers …s (altemate) (altemate) Buds in 鉱 il of of a scale-like prophyll Fig. Fig. 2. Structure of winter bud (a mixed bud) in Prunus s. L Flower buds produce no leaves and vegetative buds produce no flowers. Meaning of symbols are same as as those in Fig. 1. December December 2001 Journal of Japanese Botany Vo l. 76 No. 6 333 r--hu、.， (a) (a) ‘、J \判各例舛~ L ‘ (d) (d) Fig. Fig. 3. Growth of buds in the axil of scale 回 like prophylls in Prunus s. l. (a) Buds in the axile of scale-like prophylls prophylls do not develop. (b) Buds in the axile of scale-like prophylls of mixed shoots develop into vegetative vegetative shoots. (c) All buds in the axile of scale-like prophylls develop into reproductive shoots. (d) Buds in the axil of scale-like prophylls develop vegetative and mixed shoots in following yea r.