113 research outputs found
富山県におけるスイバ(タデ科) の染色体変異 (2012 年度 植物地理・分類学会賞受賞記念講演記録)
Following a thorough review of chromosome studies on the number, karyotype, and mitotic and meiotic chromosomal behaviors of Rumex acetosa, data collected on R. acetosa specimens in Toyama Prefecture, central Japan, are reported in this paper. A total of 1,640 individual R. acetosa specimens were collected from 17 localities in Toyama Prefecture. Nearly all individuals were diploid, with either 2n = 14 = 12+2X (1,296 individuals, 79.02%) or 2n = 15 = 12+X+ Y1Y2 (321 individuals, 19.57%). Seventeen individuals, constituting 1.04% of all plants examined, were triploid (nine individuals with 2n = 21 = 18+3X and eight individuals with 2n = 22 = 18+2X+Y1Y2). Four individuals were tetraploid (two individuals with 2n = 28 = 24+4X and two individuals with 2n = 29 = 24+3X+Y1Y2), and two individuals were aneuploid, with chromosome constitutions of 2n = 15 = 13+ 2X and 2n = 16 = 13+2X+Y2. Among the nine diploid karyotype forms classified by Ono (1935), AB was the most frequently (29.4%), followed by AD (20.1%), AA (15.7%), BB (11.3%), AC (9.6%), BD (8.6%), CD (2.5%), DD (1.8%), and CC (1.0%). No supernumerary segments (SS) were found on the A1 chromosomes of the individuals identified in the study. The frequency of SS5 chromosome occurrence in each locality of normal diploid plant A5 chromosomes was between 7.6% and 44.0%, with a mean frequency of 24.5%. These results indicate that SS5 chromosomes are prevalent, and that about one fourth of A5 chromosomes in Toyama Prefecture contain SS5 chromosomes. The frequency of SS6 chromosome occurrence in each locality of normal diploid plant A6 chromosomes was between 23.7% and 64.4%, with a mean frequency of 47.7%. These results indicate that SS6 chromosomes are also prevalent, and that nearly half of R. acetosa A6 chromosomes in Toyama Prefecture are composed of SS6 chromosomes.スイバは,性染色体が分化した雌雄異株植物(雌株は2n = 12+2X, 雄株は2n =12+ X +Y1Y2)である。Y 染色体の動原体の位置と付随体のサイズは変異することが知られている。第1,5,6常染色体には,短腕に過剰分節(supernumerary segment)が存在するタイプと存在しないタイプの2型が存在するため,スイバの核型は多様である。最初に,これまでの染色体研究について概説することで,スイバにおいて明らかにされた核型変異について紹介を行った。次に,富山県産スイバの核型変異を明らかにすることを目的として,県内の17 カ所より採集した1,640個体について染色体の観察を行い,その結果を報告した。1,640個体のうち,二倍体雌個体(2n= 12+2X)は1296個体(79.07%),二倍体雄個体(2n= 12+ X+Y1Y2)は321個体(19.57%)であった。三倍体は17個体(1.2%)含まれており,2n = 18+XXXが9個体,2n = 18+XXYYが8 個体であった。四倍体は2n = 24+XXXXと2n = 24+XXXYYがそれぞれ2個体ずつの4個体,それに2n = 15 = 13+2X(1個体) と2n = 16 =13+2X+Y2(1個体)の2個体の異数体が含まれていた。48個体(全観察個体の3%)にはB染色体が存在した。日本産スイバには過剰分節の有無により,第1常染色体(A1),第5常染色体 (A5), 第6常染色体(A6) に, それぞれに2型が知られている。観察を行った17カ所の二倍体個体における過剰分節をもった染色体の割合は,SS5(過剰分節をもつA5)が7.6% ~ 44.0%,平均24.5%であった。SS6(過剰分節をもつ A6)では23.7% ~64.4%,平均47.7%であった。過剰分節をもつ第1常染色体(SS1)は観察されなかった。イギリスにおいてSS6は1月の1日の平均気温が4.4 ℃以下の地域のスイバには存在しないことが報告されている。スイバを対象とした細胞地理学的研究において,SS1,SS5,SS6 染色体の国内での分布域を明らかにすることが望まれる
Chromosome numbers of Japanese Scutellaria (Lamiaceae)
Chromosome counts of 16 species and two varieties of Scutellaria(Lamiaceae)collected from 45 localities in Ja-pan were reported. First counts were the following 11 taxa : S . amabilis(2n=26), S . brachyspica(2n=26), S . in-dica var. parvifolia(2n=26), S . iyoensis(2n=26), S . kiusiana(2n=26), S . laeteviolacea var. laeteviolacea(2n =26), S . laeteviolacea var. maekawae(2n=26), S . muramatsui(2n=26), S . pekinensis var. transitra(2n=28), S . shikokiana(2n=28)and S . tsusimensis(2n=26). New counts were reported in S . dependens(2n=28), S . strigil-losa(2n=30)and S . yezoensis(2n=30). Chromosome counts for S . barbata(2n=26), S . guilielmii(2n=28), S . indica var. indica(2n=26)and S . rubropunctata var. rubropunctata(2n=26)were confirmed
Taxonomic relationship between Japanese Potentilla anemonefolia and Himalayan P. sundaica(Rosaceae)
Japanese Potentilla anemonefolia and Himalayan P. sundaica which are sometimes thought to be conspecific by some taxonomists were compared in morphology, phenology, dry matter allocation, karyotype and meiotic chromosome behavior. The former is diploid, with larger leaves, with larger self-incompatible flowers, having considerably vegetative reproduction, while the latter is tetraploid, with smaller hairy leaves, smaller self-compatible flowers and having less vegetative reproduction. The analysis of the artificial F1 hybrid showed slightly differentiated genomes in the two species. As a result of the present investigation, we conclude that the two taxa can be regarded as different species
異型対をもつスイバの核型
スイバの染色体構造変化個体は, 日本では Yamamoto (1935, 1937, 1938), Kurita and Kuroki (1971),Kuroki (1994) により,イギリスではWilby and Parker (1988) により報告されている。今回,3カ所で転座が生じたと判断される核型をもつスイバ雄個体が見つかったので報告する。染色体構成は 2n = 15 = 12 +X+YYであった。2本のY染色体は長さが等しく,Y1,Y2の区別はできなかった。この個体の2本のY染色体の合計長は,通常の雄個体の2本のY染色体の合計長と等しいことから,Y染色体間で転座が生じたと考えられる。X染色体の片腕は0.7 μm短くなっており,No. 1常染色体の短腕が0.7 μm長くなっていたことから,X染色体の片腕の一部がNo. 1常染色体の短腕へ転座したものと判断される。No. 4常染色体には長さ0.8 μmの短腕が無く,No. 5常染色体の短腕が0.8 μm 長くなっていたことから転座したものと判断される。このスイバ個体は,このように3カ所で転座が生じたと判断される核型をもっており,このような複数の転座をもつスイバは初めての発見である
Chromosome numbers of 193 cultivated taxa of Prunus subg.Cerasus in Japan
Chromosome counts of 193 taxa including wild taxa in the Prunus subg. Cerasus in Japan were reported. Among 193 taxa, the chromosome counts of 148 taxa were determined for the first time. The taxa studied in-cluded 161 diploids, 30 triploids, one tetraploid, and one hexaploid. This study showed that the majority of the cultivated Prunus subg. Cerasus taxa of Japan are diploid
Polyploidy of Reynoutria japonica var. japonica (Polygonaceae)in Japan
The chromosome number of Reynoutria japonica var. japonica was determined based on a total of 305 indi-viduals from 37 localities in central and northern Honshu of Japan. Plants investigated showed three chromo-some counts of 2n=44, 66 and 88. Among these, the plants with 2n=66 chromosomes are the first finding in Ja-pan. In the 37 localities studied, 15 localities had two chromosome races of any one of the following three combi-nations : 2n=44 and 66 ; 2n=44 and 88 ; or 2n=66 and 88, and five localities harbored all the three chromosome races. Reynoutria is believed to have a base number of x=11(Darlington and Wylie 1955). These chromosome counts were consistent with the proposed base number, showing euploid variation of tetraploid(2n=44),hexa-ploid(2n=66)and octoploid(2n=88). Chromosome sizes of the respective chromosome races were 1.0―1.8 μmin tetraploid(2n=44)plant, 1.1―1.8 μm in hexaploid(2n=66)plant, and 0.9―1.8 μm in octoploid(2n=88)plant. Their chromosome complements had similar ranges in chromosome length
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