COMPARATIVE ULTRASTRUCTURE OF THREE SPECIES OF CHLOROSARCINA (CHLOROSARCINACEAE,CHLOROPHYTA)1,2

Ultrastructural studies revealed that Chlorosarcina stigmatica Deason differs from C. brevispinosa and C. longispinosa Chantanachat and Bold because the vegetative cells possess a pyrenoid, and the zoospores have chlorophycean characteristics. Zoospores of the latter species exhibit pleurastrophycean characteristics including counterclockwise absolute orientation of the flagellar apparatus components. Nuclear division in C. longispinosa, like that of Friedmannia israelensis Chantanachat and Bold, is metacentric. It is suggested that a new genus, Desmotetra, be erected for Chlorosarcina stigmatica, and that it, along with Chlorosarcinopsis Herndon, be placed in the Chlorococcales, Chlorophyceae. Chlorosarcina brevispinosa and C. longispinosa belong in the Pleurastrales, Pleurastrophyceae.     

ELECTROPHORETIC AND IMMUNOLOGICAL ANALYSES OF SEVEN CHLOROSARCINACEAN ALGAE1

Proteins from 7 species of chlorosarcinacean algae representing 4 genera were studied with starch and disc gel electrophoresis and immunology to determine biochemical relationships. Migration patterns of enzymes and serological reactions indicated that 4 species of Chlorosarcinopsis were closely related, whereas Friedmannia israeliensis, Fasciculochloris boldii, and Chlorosarcina longispinosa were more diverse. Malate dehydrogenase, glutamate dehydrogenase, nonspecific alpha esterases, and peroxidase (using pyrogallol as the hydrogen donor) were present in all 7 species. No peroxidase activity occurred with benzidine. Leucine aminopeptidase was obvious in only 2 species. A single distinct band of general protein in F. israeliensis and C. longispinosa suggested the presence of homogenous reserve protein. The 7 species exhibited serological affinity to 4 isolates of Protosiphon representing diverse morphology within the genus. The data are discussed relative to current knowledge of comparative morphology of chlorosarcinacean algae.     

FINE STRUCTURE OF MITOSIS AND CLEAVAGE IN FRIEDMANNIA ISRAELENSIS (CHLOROPHYCEAE: CHLOROSARCINACEAE)1

Observations on the ultrastructure of Friedmannia israelensis Chantanachat & Bold revealed the presence of a phycoplast and zoospores with cruciate rootlets. During mitosis, the nuclear envelope partially disintegrates and the basal bodies remain at the cell surface on either side of the developing cleavage furrow. The events during mitosis and cleavage in Friedmannia resemble those reported in the other green algae, Platymonas and Pleurastrum.     

MITOSIS AND CLEAVAGE DURING ZOOSPOROGENESIS IN SEVERAL COCCOID GREEN ALGAE1

The fine structure of mitosis and cleavage in Axilosphaera vegetata Cox & Deason, Chlorococcum echinozygotum Starr, Chlorosarcinopsis eremi Chantanachat & Bold, Nautococcus mammilatus Korshikoff, N. terrestris Archibald, N. soluta Archibald, Neospongiococcum solitarium Deason, and Tetracystis aeria Brown & Bold was observed. All possess a phycoplast, but differences in basal body position during mitosis were observed. Nautococcus mammilatus differs from the others as protoplast rotation occurs in many cells prior to cleavage.     

CONCORDANCE OF MOLECULAR AND ULTRASTRUCTURAL DATA IN THE STUDY OF ZOOSPORIC CHLOROCOCCALEAN GREEN ALGAE1

Alternative evolutionary hypotheses generated from features of vegetative cell morphology and motile cell ultra-structure were investigated using a molecular data set. Complete nuclear-encoded small subunit (18S) ribosomal RNA (rRNA) gene sequences were determined for six species (three each) of the chlorococcalean green algae “Neo chloris” and Characium. Based on motile cell ultra-structure, it was previously shown that both genera could be separated into three distinct groups possibly representing three separate orders and two classes of green algae. 18S rRNA gene sequences were also obtained for three additional taxa, Dunaliella parva Lerche, Pediastrum duplex Meyen, and Friedmannia israelensis Chantanachat and Bold. These organisms were selected because each, in turn, is a representative of one of the three ultrastructural groups into which the Neochloris and Characium species are separable. Phylogenetic analyses utilizing the molecular data fully support the ultrastructural findings, suggesting that the similar vegetative cell morphologies observed in these organisms have resulted from convergence.     

ASSESSING THE RELATIONSHIPS OF SOME COCCOID GREEN LICHEN ALGAE AND THE MICROTHAMNIALES (CHLOROPHYTA) WITH 18S RIBOSOMAL RNA GENE SEQUENCE COMPARISONS1

Eight complete nuclear-encoded small-subunit ribosomal RNA (18S rRNA) gene sequences were determined for four genera of the Microthamniales (Pleurastrophyceae) and for Gloeotilopsis planctonica Iyengar & Philipose (Ulvophyceae, Ulotrichales) to investigate evolutionary relationships within the Microthamniales and the taxonomic position of this order within the green algae. Phylogenies inferred from these data revealed specific relationships at the level of genera and species that disagree with those inferred from vegetative cell morphology but agree with those inferred from motile cell characters. The rRNA phylogenies provide even better resolution than that gained from morphology alone. The coccoid lichen alga Trebouxia spp. is specifically related to other coccoid lichen and soil algae (i.e. Myrmecia biatorellae Boye-Petersen and Friedmannia israelensis Chantanachat & Bold), forming the “Lichen Algae Group,” an evolutionarily distinct lineage within the Microthamniales. Trebouxia is a paraphyletic and Pleurastrum a polyphyletic genus in rRNA phylogenies. In contrast to previous hypotheses based on morphology, Pleurastrum terrestre Fritsch & John is not closely related to Trebouxia but occupies an isolated position within the Microthamniales. The filamentous alga Microthamnion kuetzingianum is not ancestral to coccoid members of the Microthamniales but is closely related with the coccoid Fusochloris perforata (Lee & Bold) Floyd, Watanabe & Deason. The Microthamniales are inferred to be an array of independent lineages that radiate nearly simultaneously and may also include some autosporic coccoid taxa previously classified in the Chlorophyceae. Monophyly of the Microthamniales could not be demonstrated unequivocally. In contrast to a hypothesis based on ultrastructure, the Microthamniales are evolutionarily distinct from the Ulotrichales. The latter are ancestral to the radiation of the Microthamniales and the Chlorophyceae in the rRNA phylogenies.     

INFERRING TAXONOMIC POSITIONS AND TESTING GENUS LEVEL ASSIGNMENTS IN COCCOID GREEN LICHEN ALGAE: A PHYLOGENETIC ANALYSIS OF 18S RIBOSOMAL RNA SEQUENCES FROM DICTYOCHLOROPSIS RETICULATA AND FROM MEMBERS OF THE GENUS MYRMECIA (CHLOROPHYTA, TREBOUXIOPHYCEAE CL. NOV.)1

Complete nuclear-encoded small-subunit ribosomal RNA (18S rRNA) coding sequences were determined for the coccoid green algae Dictyochloropsis reticulata (Tschermak-Woess) Tschermak-Woess , Myrmecia astigmatica Vinatzer, and M. bisecta Reisigl, to investigate the taxonomic position of Dictyochloropsis Geitler and of the genus Myrmecia Printz. Phylogenies inferred from these data revealed a sister-group relationship between D. reticulata and certain coccoid green algae that lack motile stages (autosporic coccoids) within the order Microthamniales. The monophyletic origin of the Microthamniales, including autosporic coccoids previously classified in the Chlorophyceae, is clearly resolved by the rRNA sequence data. This finding. shows the considerable taxonomic breadth of that order, whose taxonomic position has been unclear so far. A new class, Trebouxiophyceae, is proposed for this group of green algae. Phylogenetic inferences from the rRNA sequences show paraphyly of the genus Myrmecia. The 18S rRNA sequence data suggest that, among taxa that share similar vegetative cell morphologies, the zoospore characters resolve better the actual genus and species boundaries. Within identical zoospore types, the rRNA data allow further resolution of taxonomic relationships. On the basis of the.se findings, I propose that the genus Friedmannia Chantanachat ± Bold be merged into Myrmecia and that only those species be left in the genus Myrmecia that are identical in particular zoospore characters (i.e. those described in detail for M. israeliensis ( Chantanachat ± Bold) comb, nov.), namely M. astigmatica, M. biatorellae (Tschermak-Woess ± Ptesst) Petersen, and M. israeliensis. Myrmecia bisecta has to be excluded from Myrmecia; its taxonomic position within the Trebouxiophyceae is unclear .     

CORRECTION OF THE NAME PSEUDOTETRAÉDRON POLYMORPHUM (CHLOROPHYCEAE)1

A unicellular chlorococcalean alga, Pseudotetraëdron polymorphum MacEntee, Bold & Archibald is renamed Chlorotetratëdron polymorphum (MacEntee, Bold & Archibald) MacEntee, Bold & Archibald became the former generic designation has been preempted by a xanthophycean alga.     

Salinity-induced changes in two cultivars of Vigna radiata: responses of antioxidative and proline metabolism

The influence of increasing salinity stress on plant growth, antioxidant enzymes and proline metabolism in two cultivars of Vigna radiata L. (cv. Pusa Bold and cv. CO 4) was investigated. Salt stress was imposed on 30-days-old cultivars with four different concentrations of NaCl (0, 100, 200 and 300 mM). The roots and shoots of CO 4 showed greater reduction in fresh weight, dry weight and water content when compared to Pusa Bold with increasing salt stress. Under salinity stress, the roots and shoots of CO 4 exhibited higher Na⁺: K⁺ ratio than Pusa Bold. The activities of reactive oxygen species (ROS) scavenging enzymes and reduced glutathione (GSH) concentration were found to be higher in the leaves of Pusa Bold than in CO 4, whereas oxidized glutathione (GSSG) concentration was found to be higher in the leaves of CO 4 compared to those in Pusa Bold. Our studies on oxidative damage in two Vigna cultivars showed lower levels of lipid peroxidation and H₂O₂ concentration in Pusa Bold than in CO 4 under salt stress conditions. High accumulation of proline and glycine betaine under salt stress was also observed in Pusa Bold when compared to CO 4. The activities of proline biosynthetic enzymes were significantly high in Pusa Bold. However, under salinity stress, Pusa Bold showed a greater decline in proline dehydrogenase (ProDH) activity compared to CO 4. Our data in this investigation demonstrate that oxidative stress plays a major role in salt-stressed Vigna cultivars and Pusa Bold has efficient antioxidative characteristics which could provide better protection against oxidative damage in leaves under salt-stressed conditions.     

NUCLEOTIDE SEQUENCE HOMOLOGY OF SOME ALGAL RIBOSOMAL RNAs1

Radioactively labeled ribosomal RNA from seven species of algae was purified and hybridized to purified DNA from Chlamydomonas reinhardtii Dangeard (Chlorophyta). Delta T_m values for the heterologous RNA-DNA duplexes were obtained by thermal dissociation; values ranged from 3.9 to 10.9 C. Organisms traditionally considered to be less closely related to C. reinhardtii showed the greatest delta T_m values. Ulothrix fimbriata Bold and Klebsormidium flaccidum (Kütz.) S., M. & Bl., although similar morphologically, showed very different delta T_m values and would not appear to be closely related by these criteria.     

Effect of Indian mustard on feeding,larval survival and development of Plutella xylostella at constant temperatures

Feeding behavior of Plutella xylostella under optional to non-optional conditions was studied at 10°C, 15°C, 20°C, and 25°C on Indian mustard, Brassica juncea. The study reveals that the variety Pusa Bahar was significantly less preferred by the larvae as compared with Pusa Bold and Varuna under optional to non-optional conditions. Larvae of P. xylostella consumed more food at 25°C than 20°C, 15°C and 10°C. Larval survival was found to be highest on cabbage (control) as compared with Indian mustard and was found to vary with host plants and temperature. The larval survival decreased to 11.29% on Pusa Bahar at 10°C. Increasing the temperature from 10°C to 20°C, larval mortality resulted more on Varuna than Pusa Bahar and Pusa Bold. Developmental period was prolonged on Pusa Bold at 10°C while it was shortest on cabbage at 25°C. A total of 536.47 degree days were required to complete the development by immature stages on Varuna at 25°C and 421.64 degree days on cabbage.     

A taxonomic revision of Centaurea section Acrocentron (Asteraceae) in Iran

The taxonomic status of Centaurea section Acrocentron in Iran is briefly reviewed. A critical study of 251 herbarium specimens, and an additional 37 accessions collected specifically for this research, led to the discovery of a new variety, Centaurea irritans var. longispinosa Montazerolghaem , and the revival of another, C. persica var. subinermis, a taxon previously treated as a synonym for about 25 years. A key to all Iranian species of Centaurea section Acrocentron is provided. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 163 , 99–106.     

ULTRASTRUCTURE AND PHYLOGENETIC RELATIONSHIPS OF CHAETOPELTIDALES ORD. NOV. (CHLOROPHYTA,CHLOROPHYCEAE)1

Vegetative cells and zoospores of Hormotilopsis gelatinosa Trainor & Bold, H. tetravacuolaris Arce & Bold, Planophila terrestris Groover & Hofstetter, and Phyllogloea fimbriata (Korchikov) Silva were examined by transmission electron microscopy. All cells had pyrenoids traversed by cytoplasmic channels. Zoospores were quadriflagellate and had essentially cruciate flagellar apparatuses. Scales were present on free-swimming zoospores. These features are essentially identical to those of Chaetopeltis sp. and are dissimilar to those of other described green algae. The new order Chaetopeltidales is created to accommodate the genera Chaetopeltis, Hormotilopsis, Planophila sensu Groover & Hofstetter, Phyllogloea, Dicranochaete, and Schizochlamys, organisms previously scattered among the orders Tetrasporales, Chloro-coccales, Chlorosarcinales, and Chaetophorales. Members of the order are closely related to the ancestral chlorophycean flagellate genus Hafniomonas, may be ancestral with respect to other Chlorophyceae, and may also be closely related to the ulvophycean order Ulotrichales.     

Rapid genetic delineation of local provenance seed‐collection zones for effective rehabilitation of an urban bushland remnant

Abstract The rehabilitation of native plant communities in urban bushland remnants is an increasingly important activity requiring the collection of large amounts of seed. Best practice generally identifies that local seed are best, but how far does the local provenance extend? Using the DNA fingerprinting technique amplified fragment length polymorphism, we assessed genetic differentiation between potential seed source populations and the target population, Bold Park, a large and significant bushland remnant in Perth, Western Australia. For each of 15 species, analysis of molecular variance was used to partition genetic variation within and among populations. Genetic differentiation between Bold Park and potential seed source populations was assessed by non‐metric multidimensional scaling ordination, and statistically by Fisher’s exact tests. The partitioning of variation among populations (Φ_ST) varied from 0.66 for Santalum acuminatum to 0.04 for Mesomelaena pseudostygia. For eight of 15 species, Bold Park plants were completely or largely non‐overlapping with other populations in ordinations, suggesting genetic differentiation and a narrow provenance. Five species showed overlap between Bold Park and some other, but not all, populations sampled, with geographically closest populations generally undifferentiated. Only two species, Acanthocarpus preissii and Mesomeleana pseudostygia, showed little genetic differentiation between Bold Park and all other populations, suggesting a regional genetic provenance. These species can be classified into three broad provenance classes – narrow, local and regional – to help guide decisions about appropriate seed‐collection zones for the rehabilitation of urban bushland remnants.     

Towards a Revision of the Systematics of the Genus Chlamydomonas (Chlorophyta)

Strains of Chlamydomonas with cross-reacting sporangium wall autolysins also correspond in morphology, reproduction, development, and physiological properties. We therefore undertook a revision of the systematics of the genus based on this correlation. Isolates of Chlamydomonas available in culture collections were re-examined microscopically, preferably with respect to their reproduction and development. In particular all authentic clones, on which earlier species diagnoses had been founded, were included. Their detectable autolysins were tested crosswise in bioassays. We intend to complete and extend species diagnoses in order to separate species more precisely. - At first 7 strains with a common sporangium autolysin have been examined, four of which are the authentic cultures of the species C. aggregate Deason et Bold, C. akinetos Deason et Bold, C. applanata Pringsheim, and C. humicola Lucksch. They have been brought together under the name of the species first described, C. applanata Pringsheim, due to their apparent similarities in morphology and development. An amended species diagnosis is presented. The significance of authentic cultures as important sources of further information is discussed.     

CHLOROPHYLL a:b RATIOS IN MARINE PLANKTONIC ALGAE1

Chlorophyll a:b ratios for Chlorella capsulata Guillard, Bold & MacEntee, Chlorosarcinopsis halophila Guillard, Bold,& MacEntee, Nannochloris atomus Butcher and Micromonas pusilla (Butcher) Manton & Parke were found to be 1.74, 2.46, 1.89, and 1.53, respectively. Compared to previously published values in marine planktonic algae, these ratios are similar to the average value (2.17, SD = 1.12) reported for 25 species in 15 genera. Both the new data and previously published data support the hypothesis that marine algae have lower chlorophyll a:b ratios than do other chlorophyll b containing plants.     

Protection of growth and photosynthesis of <Emphasis Type="Italic">Brassica juncea</Emphasis> genotype with dual type sulfur transport system against sulfur deprivation by coordinate changes in the activities of sulfur metabolism enzymes and cysteine and glutathione production

Mustard (Brassica juncea L. Czern and Coss.) cvs. Pusa Jai Kisan (with low-affinity S transporter (LAT) system) and Pusa Bold (with dual, low- and high-affinity transporters (LAT + HAT) system) were supplied with 0 or 1 mM S in hydroponics culture, and the coordinate changes in growth traits (plant dry weight and leaf area), photosynthetic traits (photosynthetic rate, intercellular CO₂, F _v/F _m, and chlorophyll content), activities of key enzymes of sulfur metabolism, such as ATP-sulfurylase (ATP-S), serine acetyltransferase (SAT), and glutathione reductase (GR), and the contents of cysteine (Cys) and glutathione (GSH) were studied in 30 days after sowing. The results showed that cv. Pusa Jai Kisan was more sensitive to S deprivation than cv. Pusa Bold. In cv. Pusa Jai Kisan, S deprivation resulted in a stronger decrease of plant growth and photosynthetic traits, Cys and GSH contents, and a notable decline in activity of ATP-S. S deprivation up-regulated GR activity to a greater extent in cv. Pusa Bold. In contrast, despite the activity of SAT, an enzyme involved in the final step of Cys biosynthesis, was increased in cv. Pusa Jai Kisan stronger than in cv. Pusa Bold under S-deprivation, it could not be translated into the increase in Cys and, thus, GSH contents and a consequent improvement in growth and photosynthesis. The study demonstrated that cv. Pusa Bold (with LAT + HAT) can be a promising cultivar for activation of Cys and/or GSH biosyntheses and increased plant tolerance to S-deprivation conditions.     

TWO DIFFERENT SPECIES OF EUGLENA,E. GENICULATA AND E. MYXOCYLINDRACEA (EUGLENOPHYCEAE), ARE VIRTUALLY GENETICALLY AND MORPHOLOGICALLY IDENTICAL1

We investigated the similarity of a single Euglena myxocylindracea strain, isolated originally by Bold and MacEntee, to several Euglena geniculata strains on both morphological and DNA levels. We found the three DNA stretches, consisting of fragments coding for the parts of cytoplasmic and chloroplast small subunit rRNA, and the internal transcribed spacer (ITS2) of cytoplasmic rDNA, with the combined length of 4332 nucleotides, are identical in E. myxocylindracea and E. geniculata, strain SAG 1224‐4b. Morphological differences between E. myxocylindracea and any E. geniculata strain examined were well within the range of E. geniculata variability as well. The only difference behind the distinction of E. myxocylindracea from E. geniculata is the presence of the second chloroplast in the latter. However, we were able to induce the appearance of the second chloroplast in the cells of E. myxocylindracea and its disappearance in the cells of E. geniculata by changing the composition of the culture media. We therefore conclude that E. myxocylindracea Bold and MacEntee should be regarded as an environmental form of E. geniculata Dujardin. For the first time the morphology of E. geniculata chloroplasts was shown as revealed by confocal laser microscopy.     

The phylogenetic relationship between the Chlamydomonadales and Chlorococcales inferred from 18SrDNA sequence data

Nuclear-encoded small subunit ribosomal RNA gene (185rDNA) sequences were determined for Chlamydomonas moewusii Gerloff and five chlorococcalean algae (Chlorococcum hypnosporum Starr; Chlorococcum oleofaciens Trainor et Bold; Chlorococcum sp.; Tetracystis aeria Brown et Bold; Protosiphon botryoides (Kützingl Klebs). All these algae are characterized by a clockwise CCW) flagellar apparatus. Phylogenetic trees were constructed from sequences from these algae together with 20 green algae. All algae with a CW flagellar apparatus form a monophyletic clade (CW group). Three principal clades can be recognized in the CW group, although no morphological character supports monophyly of any of these three clades. The 185rDNA trees clearly demonstrate the non-monophyly of the Chlamydomonadales and Chlorococcales, suggesting that vegetative morphology does not reflect phylogenetic relationships in the CW group. The paraphyly or polyphyly of the genus Chlamydomonas and Chlorococcum are also revealed. Present analysis suggests that the presence or absence of a zoospore's cell wall and the multinucleate condition have limited taxonomic values at higher taxonomic ranks.