Some New Taxa of Nitella from Guangdong,China

Guangdong Province extends across the subtropical and tropical zones. With favorable climate and plentiful rainfall, this district is extremely rich in plants. However, the study on the Charophyta in this province is scanty. The specimens we identified were collected from 4 cities and 10 counties of the province. The result shows that there are abundant representatives of Chrophyta, especially in Nitella, in the province. In this paper, however, only reported are some new taxa of Nitella. The 2 new species are Nitella sessilis and N. guangdongensis; the 3 new varieties are Nitella flagelliformis var. conglomerata, N. brevidactyla var. hainanensis and N. pakistanica var. magniantheridii; and the 3 new records of distribution in China are Nitella bengalensis Kundu, N. madagascariensis Zanev. and N. tenuissima var. sanukensis Imah.     

Some New Taxa of Charophyta from Guangxi

Guangxi, Situated in the southern border area of China, is extremely rich in Charophytes. In this paper, however, reported are only new species and new varieties. Among the new taxa, Nitella haplodactyla has only one dactyl on the fertile branchlet, N. brachyclema and N. rarissima are provided with more than 4-celled dactyls, the fertile branchlet of N. pseudoflabellata var. tetradynana has tetradynamous rays, and Chara piniformis is characterized by thehaplostichous cortex, long spinecells, and rudimentary stipulodes.     

Some New Taxa of Charophyta in China

The authors examined specimens collected from Beijing, Hebei Province and North-east China. Two new species, one variety and five new records of the Characeae from China are reported in this paper. They are Nitella nenjiangensis sp. nov., Chara vertillibracteata sp. nov., C. globularis Thuiller var. beijingensis var. nov., Nitella axillaris Braun, N. crispa Imah., N. gracillima Allan, N. pseudoflabellata var. imperialis T. F. A., Chara arru-densis Mendes.     

Materials for the Charaphyta of China

Reported in this paper are two new species, one new variety, and three new records of the Characeae collected in China. They are Nitella anhuensis sp. nov., Chara paucicarpa sp. nov., Nitella alleninda var. tenuireticulata var. nov., N. gracilliformis J. Grove., N. formosa T. F. Allen and Chara tenuispina A. Br.     

Some New Taxa and New Records of Charophyta from Guizhou

Guizhou is situated in the southwestern China and is very rich in algae However, our present knowledge of the Charophytes is scanty. Over 400 specimens were collected from 22 counties or cities and from them 41 species, 2 subspecies, 3 varieties were found. In addition to previously known species of this region, Nitella rasilis, N. paludosa, N. pseudopapillata and N. guizhouensis are new species, N. mirabilis var. libera is new variety, and N. penicillata, Chara burmanica, C. vulgaris var. gymnophylla are new records for China. In this paper, only the new taxa are reported.     

中国丽藻属两新种

本文报道的是采自广西、山东的丽藻属植物两新种,即广西丽藻(Nitella guangxiensis)和山东丽藻(Nitella shandongensis),其特征分别描述如下: 广西丽藻新种图1:1—9 Nitella guangxiensis Y. J. Ling, G. Z. Deng et Z. Li, sp. nov. Planta monoica, claro-viridis, 13-19 cm alta. Caulis robustus,diametro 610-     

Some New Taxa and Records of Characeae in Hunan,China

In this paper, one new species, four new varieties and thirteen new records of Characeae from Hunan, China, are reported. They are Chara quadriscutulum, sp. nov., Nitella axilliformis var. biformis, var. nov., N. microcarpa var. unicarpa, var. nov., Chara braunii var. cylindrospora, var. nov., C. hydropitys var. hunanensis, var. nov., Nitella microcarpa Braun, N. leptoclada Braun, N. annandalei Pal, N. confervacea A. Braun, N. gracilliformis J. Groves, N. inversa Imahori, N. musashiensis Morioka, N. paucicostata T. F. Allen, N. acuminata var. gollmeriana (A. Br.) Zanev. et Wood, Tolypella boldii Sawa. Chara longifolia Robinson, C. pistianensis J. Vilhelm, C. grovesii Pal.     

A New Species of Nitella from Sichuan

In this paper a new species of Nitella, N. vermiformis, from Sichuan is reported. The new species is the similar to Nitella procera Han from Yunnan. But gametangia of the latter grow in every furcte, and fertile branchlets are similar to sterile ones. There are not central radial branchlets and accessory branchlets in first furcate branchlet; the membrane ofoospore is vermiform-processed.     

Method of recording the linear growth and cell mass displacement of multicellular animals and plants

A photoelectrical method has been developed of registration of the linear growth and cell mass movements in the actively zones (growing tips, edges, etc). The device proposed transforms to electrical signals the changes in lighting of microscopic visual field caused by shifting the growing structures in the area restricted by the aperture of the ocular field diaphragm of the "cat-eye" type. By means of this technique, oscillograms of growth of the number of multicellular organisms have been obtained for the first time. In many cases (blastodisc edge and tail bud of the salmon Oncorhynchus gorbusha, mantle edge of Mytilus edulis, osculum edge of the sponge Tethya, apical area of brown alga Fucus and of red algae Polyides and Ahnfeltsia), a pulsatory character of growth (with periods of some minutes) were registered. A similar growth character was also confirmed for several species of Thecaphora hydroids. No pulsations was registered during the linear growth of a brown alga Laminaria (which contrary to Fucus is growing intercalarly), of Nitella (Charophyta) and of several high plants.     

Significance of a new chromosome number in Nitella mirabilis Nordst. ex Groves em. R.D.W.

The new chromosome number n = 9 has been reported in Nitella mirabilis Nordst. ex. Groves em. R.D.W. Discussing the significance of this new chromosome number with regard to arthrodactylous and anarthrodactylous groups of the genus Nitella, the possible origin of a 9 chromosome form of N. mirabilis due to hybridization has been suggested.     

Oospore dimensions and wall ornamentation patterns in Swedish charophytes

The ultrastructural features of oospore wall ornamentation patterns revealed by scanning electron microscopy are important taxonomic characters of the Charales. The present study shows inter-and intrapecific variations in 19 species of the genera Chara, Lamprohamnium, Nitella and Tolypella. This is the first time that the oospore wall ornamentation of Swedish Charales has been documented in detail. In the studied Chara species the ornamentation within species was variable, and partly overlapping between species, but only between closely related species. In contrast, the Nitella species showed distinct differences in ornamentation patterns between species, although the same patterns can be found in different species. This study presents for the first time SEM images of the species Chara rudis (pustular ornamentation), Nitella opaca (pitted ornamentation) and Nitella wahlbergiana (anastomosing network ornamentation). The ornamentation pattern in the Nordic species TV. wahlbergiana , supports its separation from Nitella mucronata which has a reticulate ornamentation. The relationship between length and width of the oospores is also of taxonomic significance. Nitella and Tolypella oospores are roundish, whereas those of Chara and Lamprothamnium are elongate. The extent to which environmental and genetic factors can affect oospore size and shape within a species are still unknown, but in the present study both ornamentation pattern and size provided evidence for the distinction between Chara globularis and Chara aspera. Some further taxonomic problems in the Charales are discussed in the light of the results of this study.     

Polar auxin transport: an early invention

In higher plants, cell-to-cell polar auxin transport (PAT) of the phytohormone auxin, indole-3-acetic acid (IAA), generates maxima and minima that direct growth and development. Although IAA is present in all plant phyla, PAT has only been detected in land plants, the earliest being the Bryophytes. Charophyta, a group of freshwater green algae, are among the first multicellular algae with a land plant-like phenotype and are ancestors to land plants. IAA has been detected in members of Charophyta, but its developmental role and the occurrence of PAT are unknown. We show that naphthylphthalamic acid (NPA)-sensitive PAT occurs in internodal cells of Chara corallina. The relatively high velocity (at least 4-5 cm/h) of auxin transport through the giant (3-5 cm) Chara cells does not occur by simple diffusion and is not sensitive to a specific cytoplasmic streaming inhibitor. The results demonstrate that PAT evolved early in multicellular plant life. The giant Chara cells provide a unique new model system to study PAT, as Chara allows the combining of real-time measurements and mathematical modelling with molecular, developmental, cellular, and electrophysiological studies.     

Review: Taxonomy of Nitella (Charales, Charophyceae) based on comparative morphology of oospores and multiple DNA marker phylogeny using cultured material

The genus Nitella is the largest group in the Charales and has the highest diversity of vegetative and oospore morphologies. In his worldwide monograph on the Charales, R. D. Wood characterized the sections and species of Nitella mainly on the basis of vegetative morphology and treated oospore wall morphology as diagnostic at the infraspecific level. Therefore, many species of Nitella exhibiting distinct external morphology of the oospore wall (EMOW) were reduced to infraspecific rank and only 53 of 204 species previously described were recognized within Nitella . However, recent morphological and molecular phylogenetic studies have demonstrated the phylogenetic validity of using EMOW for diagnosing some species of Nitella . More recently, a scanning electron microscopy (SEM) study of internal morphology of the oospore wall (IMOW) and multiple DNA marker analyses using both nuclear and chloroplast gene sequences were conducted to improve our understanding of the taxonomy of Nitella at the species level, on the basis of cultured material of a large number of species. Multiple DNA marker analyses resolved detailed and robust phylogenetic relationships within the genus and demonstrated the taxonomic and phylogenetic significance of IMOW. In addition, they supported the taxonomic decisions based on differences in oospore morphology, suggesting that an integrated approach, involving both SEM studies of the EMOW and IMOW and multiple DNA marker analyses, is appropriate to address problems at lower taxonomic levels within the genus, as well as to construct a natural taxonomic system for the genus. In this paper, recent morphological and molecular phylogenetic studies are reviewed and recent improvements in taxonomy of Nitella are summarized. Moreover, the evolution of morphological features and phylogenetic relationships within Nitella are discussed, focusing especially on oospore morphology.     

A NEW SPECIES OF NITELLA (CHARACEAE) BELONGING TO THE NITELLA FLEXILIS SPECIES GROUP IN NORTH AMERICA12

A new species of Nitella belonging to the N. flexilis species group is described. The neiu species shows definite relationships to N. flexilis, N. opaca, N. missouriensis, and N. mirabilis. Relationships of the new species to N. acuminata are also discussed.     

中国轮藻植物区系研究

中国轮藻植物有13种分布区类型,其中以中国特有分布占绝对优势,其它分布类型所占比例较低,说明中国轮藻植物与其它地区轮藻植物联系较少。丽藻属有10种分布区类型,缺少温带特性的分布区类型,如北温带分布、旧世界温带分布,其它分布区类型显示丽藻属主要分布在热带和亚热带地区,而轮藻属有13种分布区类型,温带特性的分布区类型所占比例较高,如旧世界温带分布,其它分布区类型显示轮藻属主要分布在温带地区。     

Algae from the Rhynie Chert

New material collected from the Rhynie Chert Bed (Siegenian age) has revealed new filamentous and unicellular algae. Two of the filamentous forms and one palmelloid form are described. Filamentous and unicellular algae are particularly common in a white kind of chert not previously reported and which is interpreted as having been formed by the in situ silicification of a silicate-rich pond.
Some rhizoid-nodes of Palaeonitella cranii (Kidston & Lang) Pia and a possible rhizoid-borne pro-embryo are also described and compared with similar structures in living Charophyta.     

轮藻植物在澳大利亚的重新发现之探密

澳大利亚轮藻植物研究历史悠久,迄今约有95种被描记。在Wood(1972)对澳大利亚轮藻植物的修订研究中,一些种因为标本遗失或已损坏而未包括在内,其中有的种近年来又被重新发现。本文重点介绍Nitella hookeri A．Br．var．arthroglochin A．Br．,Lychnothamnus barbatus(Meyen)Leonh．和Nitella partita Nordst．的发现过程及其产地生态环境,探讨了季节性湿地对轮藻植物的保护意义。N．hookeri var．arthroglochin早在1854年就发现于澳大利亚,并于1887年再次作为澳大利亚特有物种而被记录,然而从此销声匿迹,直至1989年才再度问世,它重新出现的地点为新南威尔士州高海拔花岗岩风化土壤地区的季节性溪流中。L．barbatus则为R．D．Wood首次发现于1960年,嗣后一再搜寻并无踪迹,直到1996年才于昆士兰东南地区亚热带阵发性溪流中被再次发现。昆士兰中部干旱地区1889年一度见到的N．partita,也是近一百年后才在新南威尔士州西北干旱地区的季节性湿地再次发现。     

139 Taxonomic Re-Examination of Eight Species of Nitella (Charales, Charophyceae) from Asia, And Phylogenetic Relationships Within the Genus Based on rbcL and Atpb Gene Sequences

Eight taxa of Nitella, collected from Asia, were investigated using LM and SEM of the oospores and sequencing of rbc L gene to improve understanding of their taxonomic status. Our SEM observations demonstrated that the oospore morphology of six taxa – N. capitulifera (= N. acuminata f. capitulifera ), N. japonica (= N. furcata f. japonica ), N. tumulosa (= N. furcata f. tumulosa ), N. megaspora comb. nov. (= N. pseudoflabellata f. megaspora ), N. gracillima (= N. gracilis f. gracillima ), and N. axilliformis (= N. translucens f. axilliformis ) – is distinctly different from that of the species to which R.D. Wood assigned them as infraspecific taxa. Our rbc L sequence data showed that N. japonica is separated phylogenetically from N. furcata , N. tumulosa from N. furcata , N. megaspora from N. pseudoflabellata , and N. axilliformis from N. translucens . In addition, to re-examine the taxonomic system of Nitella proposed by R.D. Wood, who treated oospore wall ornamentations as a diagnosis at the infraspecific level, we carried out molecular phylogenetic analyses using the combined sequence dataset for atpB and rbc L genes of these eight species, as well as twelve species of Nitella previously studied. The combined sequence data resolved five robust clades within the subgenus Tieffallenia that were characterized by differences in oospore wall ornamentation. However, the species and sectional diagnoses of R.D. Wood, such as the form and cell number of dactyls in vegetative thalli, were variable within the clades. Therefore, R.D. Wood's taxonomic system appears unnatural, at least within the subgenus Tieffallenia .     

Submerged macrophyte seed bank in a Mediterranean temporary marsh: abundance and relationship with established vegetation

The abundance and composition of the submerged macrophyte seed bank in the Doñana marsh (southwestern Spain) was evaluated to assess its relationship with the overlying vegetation. The results obtained demonstrate the existence of a dense seed-bank, both in terms of the number of seeds and their biomass, which represented about 10% (5% for angiosperms and >20% for Charophyta) of the total plant biomass, which ensures the maintenance of the annual submerged macrophyte populations of the seasonally inundated Donñana marsh. Seed bank and established vegetation were coupled, as reflected in the existence of significant correlations between their structure and abundance. This coupling was lacking for Charophyta, whose oospores are widespread and abundant across the marsh, even at locations where they are absent, or rare, in the established vegetation. These differences between the seed bank of annual angiosperms and Charophyta appear to reflect, in part, structural differences between angiosperm seeds and Charophyta oospores, with important ecological consequences. An important aspect of these differences is the allocation of Charophyta reproductive effort to many small propagules lacking embryo storage, compared to those of angiosperms, which ensures their efficient dispersal and numerical abundance in the seed bank.     

Identification of a new characteristic species of <Emphasis Type="Italic">Nitella</Emphasis> (Charophyceae) from southwestern China based on morphology and molecular phylogeny

Nitella fuiana Lan & Qing sp. nov., a special kind of charophyte from Mingshan, Sichuan, China, was described in this study. The systematic position of the new species was assessed based on morphological and molecular analysis. The results of morphology comparison showed that the charophyte possessed stipulodes and 10-cell coronula. Nuclear 18S rDNA and plastid rbcL sequences analysis revealed that N. fuiana was a single clade as clustered with other species of Nitella. Combined with the morphological and molecular analysis data, our study strongly supported that N. fuiana was a new species of Nitella. This is the first report of Nitelleae species with stipulodes, which increased the morphological diversity of charophytes. This study also reminds us to pay close attention to the characteristics of stipulodes for further research on charophytes.