Comparative karyomorohplogical studies in four species and one variety of Mosla Buch.-Ham. ex Maxim. (Lamiaceae) in Japan

Abstract

ABSTRACT. Karyomorphology of four species and one variety of Japanese Mosla were observed. They had commonly chromosomal characters at resting nuclei of the complex chromocenter type, and the mitotic metaphase cells showed 2n=36 for M. japonica, 2n=18 for M. chinenis, M. scabra, M. dianthera and M. dianthera var. nana. The chromosome numbers of 2n=18 and 36 were considered diploid and tetraploid, respectively if the basic number x=9 was accepted. The chromosome number of 2n=18 for M. dianthera var. nana was reported here for the first time, and that of the other four species were verified with the previous reports. The karyotypes of five taxa had commonly similar karyomorphology to each other except for chromosome numbers; small sized chromosomes (2.2 to 1.1 µm long), mono-modal (gradual) decrease in chromosome length from the longest to the shortest chromosomes, and consists of median-and submedian-centromeric chromosomes. The genus Mosla Buch.-Ham. ex Maxim. is one of the three genera in the subtribe Perillinae Briq., the family Lamiaceae (Labiatae), consists of about 22 species (Wu and Li 1977b;Li and Hedge 1994), that are commonly annual herbs and aromatic plants, and grow in grassy slopes, forest margins, hills thickets, open hills and stream-sides in temperate regions of India, Southeast Asia and East Asia. Among the species of this genus, 12 species are found in China (Li and Hedge 1994) and four species and one variety grow in Japan (Murata and Yamazaki 1993). KEYWORDS:Seven species (including a synonym) of Mosla have been cytologically studied previously and documented their chromosome numbers as n=9, 2n=18 and 2n=36 (e.g., Sugiura 1931;Suzuka 1953;Mehra and Gill 1968;Gill 1971Gill , 1984Probatova and Sokolovskaya 1986;Sokolovskaya et al. 1986;Zhang and Xu 1988;Hsieh and Huang 1999), and these studies are only chromosome numbers reports. This paper reports detailed karyomorpholoies (the resting nucleus and the mitotic metaphase chromosomes) in the Japanese species of Mosla. MATERIALS AND METHODSSixty-nine plants of four species and one variety of Mosla were collected in 14 localities in Japan ( Fig. 1; Table 1), and cultivated in unglazed plant-pots in shade place in the experimental garden of Showa Pharmaceutical University. Chromosome observations were made in meristematic cells of fresh root tips. They were cut off 5-10 mm long and pretreated in 2 mM 8-hydroxyquinoline at ca 20ºC for 4 h and then fixed in 45% acetic acid at ca 2ºC for 10 min. They were macerated in a mixture of 45% acetic acid and 1N hydrochloric acid (1:1) at ca 60ºC for 20-23 sec and were then stained with 2% aceto-orcein at room temperature in moist chamber with 45% acetic acid for ca 30 min and were prepared by the conventional squash method. The slides were faintly heated under an alcohol frame for 1-2 sec before observation. Measurements of chromosome length were made in each average length in several good metaphase cells.Morphological type of the resting nuclei was classified for Tanaka (1971, 1977), and classifications of mit...

Karyomorphology of Perillula reptans Maxim., Lamiaceae, endemic species in Japan

“…Cytological features in these three genera, Perillula had 2n=14 chromosomes with x=7, 2.8-1.7 µm long with chromosome Table 1. Collection sites, sample numbers and chromosome numbers of Perillula reptans observed in this study sizes and asymmetric centromere positions with karyotype as described above, Perilla had 2n=20 and 40 chromosomes with x=10, 2.2-1.2 µm long with chromosome sizes and symmetric centromere positions with karyotype (e.g., Honda et al 1994;Funamoto unpublished), and Mosla had 2n=18 and 36 chromosomes with x=9, 2.1-1.1 µm long with chromosome sizes and symmetric centromere positions with karyotype (e.g., Funamoto et al 2014). Relation ships in these three genera, Perilla and Mosla are closely related than Perillula in these cytological characters except for basic chromosome numbers.…”

Comparative microscopic investigations of leaf epidermis in four Ajuga species from Korea

“…The remaining two species are distinguished by leaf size: 1.5–3 cm in A. multiflora and >8 cm in A. spectabilis (Kim et al, 2013; Suh et al, 2007). Although substantial progress has been made toward understanding systematic relationships in the genus Ajuga based on both chromosomal and molecular phylogenetic data (Choi et al, 2019; Funamoto & Ishii, 2003; Köse et al, 2018; Xiang et al, 2018), detailed micromorphological investigation of Korean Ajuga species are limited despite leaf epidermal characters providing useful information for taxonomy/systematics in other genera in Lamiaceae (Abu‐Asab & Cantino, 1987; Cantino, 1990; Moon & Hong, 2003).…”