Variability of the pennatae diatom Gomphonema ventricosum Gregory from far eastern lakes

The present study examined by light microscope the morphological variations of 625 specimens of Gomphonema ventricosum Gregory collected from Lake Hövsgöl (Mongolia), Lake Baikal (Russia) and Lake Kurilskoye (Kamchatka, Russia). We classified the specimens into five types with respect to valve outline; (1) type A (type form of Gomphonema ventricosum), (2) type B (Lake Baikal type), (3) type C (Lake Karluk type), (4) type D (Gomphoneis septa type) and (5) type E (G. ventricosum f. curta type). Based on the relative frequencies of these five types, specimens from Lake Baikal were shown to be different from those of the other two lakes. Specimens from Lake Baikal are remarkably smaller both in length and breadth; specimens from the other two lakes are longer than those from Lake Baikal, though specimens from Lake Kurilskoye are wider than those from Lake Hövsgöl. Thus, clear differences in morphological features are recognized between the specimens from these three lakes

カナダ ホッキョクケン エンガン ノ リクスイイイキ デ エタ ケイソウ Navicula sensu lato ノ ブンルイガクテキ ケントウ

1997年7-8月に,アムンゼンが航海した北西航路の逆コースの航海に参加した.その時に寄港したHerschel Isl.,Smoking Hills,Holman,Byron BayおよびCambridge Bayで採集した珪藻サンプルを基に,Navicula sensu latoに属す35 taxaを同定した.その内訳は Navicula 20 taxa,Chamaepinnularia 4 taxa,Craticula,Placoneis各2 taxa,Aneumatus,Caloneis,Fallacia,Naviculadicta,Parlibellus,Pinnuavis,Sellaphora各1 taxonである.これらの珪藻には分布上,広汎性種とされている種,北方性・山岳性種とされている種と,この地域の固有種が混在している.また,今回調査したのはすべて陸水域であるにもかかわらず,淡水性種,汽水性種,海産種が混在している.上記の混在率は緯度,地形,陸水域の位置などによって異なる.陸水域であるにもかかわらず汽水性種,海洋性種が見られるのは,風送塩による陸水域の鹹水(かんすい)化が原因と推察できる.今回,次に示す七つの新組み合わせを行う.Chamaepinnularia soeherensis (Krasske) Lange-Bert. & Krammer var. hassiaca (Krasske) H. Fukush. et al.Chamaepinnularia soeherensis (Krasske) Lange-Bert. & Krammer var. inflata (Krasske) H. Fukush. et al.Chamaepinnularia soeherensis (Krasske) Lange-Bert. & Krammer var. linearis (Krasske) H. Fukush. et al.Chamaepinnularia soeherensis (Krasske) Lange-Bert. & Krammer var. muscicola (J.B. Petersen) H. Fukush. et al.Placoneis amphibola (Cleve) E.J. Cox var. amphibola f. alaskensis (Foged) H. Fukush. et al.Placoneis amphibola (Cleve) E.J. Cox var. amphibola f. rectangularis (Foged) H. Fukush. et al.Placoneis amphibola (Cleve) E.J. Cox var. arctica (R.Patrick & Frese) H. Fukush. et al.We identified 35 taxa of Navicula sensu lato in materials from inland waters at Herschel lsland, Smoking Hills, Holman, Byron Bay and Cambridge Bay while sailing across the reverse course of the Northwest Passage in July and August 1997. We found 20 taxa of Navicula, 4 of Chamaepinnularia, 2 each of Craticula and Placoneis, and 1 each taxon of Aneumatus, Caloneis, Fallacia, Naviculadicta, Parlibellus, Pinnuavis, and Sellaphora. The materials contain cosmopolitan species intermingled with subalpine or mountain species and endemic species (Table 1). Although samples were collected from inland waters, brackish or marine species (see Table 1) were mixed with fresh-water species similar to those reported from Antarctica. The occurrence of brackish-water and marine species is though to be made possible by the eolian transport of salt to inland water bodies. We propose the following seven new combinations: Chamaepinnularia soeherensis var. hassiaca, Chamaepinnularia soeherensis var. inflata, Chamaepinnularia soeherensis var. linearis, Chamaepinnularia soeherensis var. muscicola, Placoneis amphibola var. amphibola f. alaskaensis, Placoneis amphibola var. amphibola f. rectangularis, and Placoneis amphibola var. arctica

シュウホクセイ ケイソウ Navicula streckerae Lange-Bert. & Witk. トクニ テンモン ニ ツイテ

Navicula streckeraeはドイツ北部の2地点と北極海で記録されている種であるが,今回フブスグル(Khovsgol)湖(モンゴル)とカムチャッカで見出した(図1).本種はユーラシア大陸の北緯50度以北に分布する周北性珪藻である.また,本種はその形態より北極海型,Weser川型,Kinzig川型に3区分できる.ヨーロッパとカムチャッカの三つの型について形態と計測値の比較を行う. 条線を構成する点紋の密度は1980年代に入ってから種を区分する特徴の一つとして重要視されてきた.しかし,珪殻の部位による点紋密度の変化の調査はどの種についても行われていないようである.今回ヨーロッパとカムチャッカ産の試料で詳しく調査を行った結果,中心域を形成する短い条線と先端部,Voigtの欠落付近の点紋密度の変化は大きく,その他では比較的安定していることが判明した.点紋密度の計測はこの部分で行うべきである.Navicula streckerae was recorded in two locations of northern Germany and the Arctic Ocean. According to the findings of this taxon from Lake Khovsgol (Mongolia) and Kamchatka (Russia) by our investigations, this taxon distributed northward from latitude 50°N. on the Eurassian Continent and is considered to be a circumboreal diatom. This taxon is divided into three types, namely the Arctic Ocean type, the Weser River type and the Kinzig River type according to the valve morphology. In this study we compare these three types in the samples from Europe and Kamchatka focusing on the valve form and sizes. Though the density of lineolae composing striae is one of the important characteristics to classify the species, there are few records of this point. We investigate this point in detail in the specimens from Europe and Kamchatka. Consequentry the two extreme values, short striae forming the cental area and the area including Voigt discontinuities, should be excluded when measuring the density of lineolae to obtain a stable value

Insights into Land Plant Evolution Garnered from the Marchantia polymorpha Genome.

The evolution of land flora transformed the terrestrial environment. Land plants evolved from an ancestral charophycean alga from which they inherited developmental, biochemical, and cell biological attributes. Additional biochemical and physiological adaptations to land, and a life cycle with an alternation between multicellular haploid and diploid generations that facilitated efficient dispersal of desiccation tolerant spores, evolved in the ancestral land plant. We analyzed the genome of the liverwort Marchantia polymorpha, a member of a basal land plant lineage. Relative to charophycean algae, land plant genomes are characterized by genes encoding novel biochemical pathways, new phytohormone signaling pathways (notably auxin), expanded repertoires of signaling pathways, and increased diversity in some transcription factor families. Compared with other sequenced land plants, M. polymorpha exhibits low genetic redundancy in most regulatory pathways, with this portion of its genome resembling that predicted for the ancestral land plant. PAPERCLIP

Circumboreal diatom Navicula streckerae Lange-Bert. & Witk., especially on lineolae

Navicula streckerae was recorded in two locations of northern Germany and the Arctic Ocean. According to the findings of this taxon from Lake Khovsgol (Mongolia) and Kamchatka (Russia) by our investigations, this taxon distributed northward from latitude 50°N. on the Eurassian Continent and is considered to be a circumboreal diatom. This taxon is divided into three types, namely the Arctic Ocean type, the Weser River type and the Kinzig River type according to the valve morphology. In this study we compare these three types in the samples from Europe and Kamchatka focusing on the valve form and sizes. Though the density of lineolae composing striae is one of the important characteristics to classify the species, there are few records of this point. We investigate this point in detail in the specimens from Europe and Kamchatka. Consequentry the two extreme values, short striae forming the cental area and the area including Voigt discontinuities, should be excluded when measuring the density of lineolae to obtain a stable value

Taxonomy of Navicula sensu lato (diatom) collected from inland waters in Arctic Canada

We identified 35 taxa of Navicula sensu lato in materials from inland waters at Herschel lsland, Smoking Hills, Holman, Byron Bay and Cambridge Bay while sailing across the reverse course of the Northwest Passage in July and August 1997. We found 20 taxa of Navicula, 4 of Chamaepinnularia, 2 each of Craticula and Placoneis, and 1 each taxon of Aneumatus, Caloneis, Fallacia, Naviculadicta, Parlibellus, Pinnuavis, and Sellaphora. The materials contain cosmopolitan species intermingled with subalpine or mountain species and endemic species (Table 1). Although samples were collected from inland waters, brackish or marine species (see Table 1) were mixed with fresh-water species similar to those reported from Antarctica. The occurrence of brackish-water and marine species is though to be made possible by the eolian transport of salt to inland water bodies. We propose the following seven new combinations: Chamaepinnularia soeherensis var. hassiaca, Chamaepinnularia soeherensis var. inflata, Chamaepinnularia soeherensis var. linearis, Chamaepinnularia soeherensis var. muscicola, Placoneis amphibola var. amphibola f. alaskaensis, Placoneis amphibola var. amphibola f. rectangularis, and Placoneis amphibola var. arctica