Finding morphological differences between cytotypes that are stable throughout their geographical range is important for understanding evolution of polyploid complexes. The ancient monocot lineage Acorus includes two groups, of which A. calamus s.l., an important medicinal plant, is a polyploid complex with a centre of diversity in Asia. European plants are sterile triploids introduced by humans. An early study suggested that plants from temperate Asia are tetraploids, but subsequent work revealed diploids and triploids rather than tetraploids in Asiatic Russia; however, cytotype diversity in Western Siberia is insufficiently known. We document the occurrence of diploids and triploids in Western Siberia. Triploids that do not differ in genome size from European Acorus are abundant in the valley of the river Ob where the ability for extensive vegetative propagation provides ecological advantages. An isolated population of aneuploid triploids with 33 chromosomes is found outside the Ob valley. Flow cytometry provides an efficient tool for identification of aneuploid plants in Acorus. All triploids are sterile, but their flowers develop uniform parthenocarpic fruits. Fruits of diploids usually vary in size within a spadix depending on the number of developing seeds. In contrast to North America, where the native diploid plants differ from the introduced triploids by the absence of a secondary midrib of the ensiform leaf blade, Siberian diploids are similar to triploids in possessing a secondary midrib. We confirm that diploids differ from triploids in the size of air lacunae in leaves, which is determined by cell number rather than cell size in septa of aerenchyma. A combination of spathe width and spadix length measured after the male stage of anthesis shows different (slightly overlapping) patterns of variation between diploids and triploids in our material.
ABSTRACT. Forty plants of Parnassia palustris var. multiseta collected in nine localities in Russia were studied in chromosome botany. They showed differentiation of the somatic chromosome numbers of 2n=18, 27 and 36, that could be diploid, triploid and tetraploid, respectively, of which the chromosome number of 2n=27 was reported here for the first time. The plants of 2n=18 and 36 chromosomes had commonly high pollen stainability and showed significantly different pollen grains in size from each other. The Parnassia palustris complex has been reported various different chromosome numbers from 2n=18 to 54 included in aneuploidy and autoploidy by many researchers (e.g., Erlandsson 1942;Kliphuis et al. 1965;Krogulevich 1978;Engelskjon 1979;Löve and Löve 1982;Gornall 1985;Funamoto 1986;Hultgård 1987; Gornarl and Wentworth 1993;Funamoto et al. 1994Funamoto et al. , 2002Wentworth and Gornall 1996;Lövkvisk and Hultgård 1999). KEYWORDS:In 2003 and 2004, we made field trips in Primorye and Altai Territories, Russia. According to Czerepanov (1995), these Territories record three species of Parnassia and we collected and studied P. palustris L. var. multiseta Ledeb. in somatic metaphase chromosomes and pollen grains. MATERIALS AND METHODSTotal 40 living samples of Parnassia palustris L. var. multiseta Ledeb. were collected in ten sites in nine localities in Primorye and Altai Territories, Russia ( Fig. 1; Table 1). These plants were cultivated in pots in shade place in the experimental garden of Showa Pharmaceutical University. Mitotic metaphase chromosomes were prepared in meristematic cells in fresh root-tips. Fresh root-tips were cut off in 5-10 mm long and pretreated in 2mM 8-hydroxyquinoline for 4h at ca 20°C before they were fixed in 45% acetic acid for 10 min at ca 2°C. They were macerated in a mixture of 1N hydrochloric-acid and 45% acetic-acid (1:1) for 20-23 sec at ca 60°C, were stained in 2% aceto-orcein for ca 30 min at room temperature in a moist chamber with 45% acetic-acid and then, were squashed in 2% aceto-orcein by the conventional method.Classification of Chromosome complements by the centromeric positions at mitotic metaphase followed Levan et al. (1964).Pollen grains were stained with 2% aceto-orcein to count at least first 3,000 grains for pollen stainability. After the photography, sizes of pollen grains were measured in length and width with a dial caliper, and analyzed with significant t-test.
ABSTRACT. Characters of the resting, the mitotic prophase and metaphase chromosomes in three species of Thymus were studied. The species studied had commonly resting chromosomes of the complex chromocenter type and mitotic prophase chromosomes of the proximal type. Thymus mongolicus showed the chromosome numbers of 2n=26 and 27 and T. przewalskii and T. roseus showed the chromosome number of 2n=26. The chromosome number of 2n=26 for T. przewalskii and that of 2n=27 for T. mongolicus were reported here for the first time and that of 2n=26 for T. roseus and T. mongilicus verified the previous reports. The chromosome number of 2n=27 for T. mongolicus seemed to have one B-chromosome as 2n=26+1B with respect to the existence of a peculiar heteropycnotic body at resting stage and high pollen stainability. Three species were commonly placed in the diploid level if the basic chromosome numbers of x=13 was accepted. Their karyotypes at mitotic metaphase were quite similar to each other regarding chromosome sizes, chromosome types according to the centromeric position and mono-modality of chromosome lengths from the longest to the shortest chromosomes except for satellite sizes. Thymus L., the Lamiaceae (Labiatae) is small subshrub plants and consists of approximately 400 species (Willis 1982). They are distributed in the temperate zone of the Eurasian continent, mainly in the Mediterranean region (Willis 1982) and grow in diabase, serpentine and calcareous rocks, limestone, in cracks rocks, on a bank, steppe, on sandy soils, xerophilous grassland, on loessic slopes and along road sides. Thymus has always been taxonomically problematic group and views concerning the taxonomic definition of the forms are extremely varied. It produces some natural hybrids. Plants of the genus is often cultivated and propagate to extract the aromatic ethereal oil and flavouring. KEYWORDS:The first cytological observation in Thymus was counting and documenting the chromosome number: 2n=24 in T. serpyllum reported by Löve and Löve (1942). Then, many more researchers have found at least 50 different chromosome numbers from 2n=14 of T. seravschanicus to 2n=90 of T. zygioides var. lycaonicus. They also have found aneuploidy in T. longedentatus as well as autoploidy in about 170 taxa included 139 species, 17 subspecies, 12 varieties and two hybrids by Löve and Löve (1942), Saaremaa (1947), Jalas (1948), Jalas and Kaleva (1966Kaleva ( , 1967, Trela-Sawicka (1968, 1970, Gogina and Svetozarova (1972), Gurzenkov (1972), Lee (1972), Jalas and Uotila (1976), Krogulevich (1978), Arrigonia et. al. (1980, Bir and Saggoo (1980), ElenaRoselló (1980), Morales Valverde (1980, 19861986a, 1990, Astanova (1981), Hruška and Bellomaria (1982), Fernandes and Leitao (1984), Funamoto et. al. (1993), Markova and Goranova (1994, Mártonfi and Mártonfiova (1996), Boscaiu et al. (1998), Tahiri et al. (1998, Constantinidis et al. (2002). Jalas (1948), Jalas and Kalev (1967) and Mártonfi and Mártonfiova (1996) and Mehrpure et al. (2002) have discussed chromosomal evolutio...
Проведен анализ относительного содержания ДНК образцов Selaginella borealis и Selaginella sanguinolenta из различных регионов. Выявлен высокий полиморфизм в относительном содержании ДНК, который связан видимо с различиями в основном хромосомном числе между различными популяциями. Также выявлено одно полиплоидное растение.
Cystopteris fragilis collected in Mongolian Altai showed three cytotypes with chromosome numbers of tetraploid (2n=c.168), pentaploid (2n=c.210) and hexaploid (2n=c.252). Flow cytometry analysis also showed three different peaks of DNA contents of nuclei in fronds. Meiotic metaphase chromosomes of the spore mother cells in the tetraploid and hexaploid C. fragilis showed all bivalents with c.84 II and c.126 II , while those of the pentaploid C. fragilis showed many univalents and bivalents that produced mostly sterile spores. The pentaploid C. fragilis was suggested to be a hybrid between the tetraploid and the hexaploid C. fragilis.
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