Book review

Fucoid macroalgae are important primary producers and habitat modifiers on North Atlantic intertidal rocky shores. With decreasing latitude, western European fucoid populations display reduced levels of abundance, biomass and recruitment, while experiencing higher levels of physical environmental stress during summer months. We hypothesized that such reduction in the south is accompanied by a detectable decline in fucoid reproductive capacity. To test this hypothesis, morphological and reproductive traits of core (Welsh) and marginal (Portuguese) populations of two common fucoid species, Fucus vesiculosus and F. spiralis (Ochrophyta, Fucales), were examined. Morphological measurements showed that for a given thallus length, both fucoid species had smaller thallus volume and lower biomass in the southerly marginal part of the range. Significantly lower biomass of reproductive tissue of F. vesiculosus and a smaller number of receptacles per individual on specimens of both species indicate that levels of reproductive output are probably lower in southern populations. Despite the differences in reproductive traits observed between regions, reproductive effort (measured as the percentage of total dry biomass represented by reproductive tissue) of both species remained similar, as algae from both regions made similar investments in reproduction. The results indicate that stressful conditions reduced growth and number of receptacles of both species and amount of reproductive biomass of F. vesiculosus in the south but do not seem to change the way these algal species invest their energy. The decline in mass and reproductive biomass of specimens from southern shores found in this study, when combined with the lower abundance of adults and lower recruitment levels previously observed, is a strong indication of fucoid populations with lower levels of propagule output. This is an important factor when considering responses of these populations to a changing environment.     

Prasiolales (Chlorophyta) von Helgoland

In their natural habitats, some representatives of Prasiolales are regularly, or often, washed by waves; others are sprayed with sea-water only occasionally, or not at all. In correspondance to this ecological grouping, species require marine or freshwater media respectively for optimal growth in cultures. The halophilic group consists ofPrasiola stipitata andRosenvingiella constricta. Though not analysed in detail, morphological characters and behaviour in cultures suggest that several different species are united under the namePrasiola stipitata. Rosenvingiella constricta, new for Helgoland and thus far reported only twice in Europe, is a dioecious haplont; both meiosis and genotypic sex-determination occur in the germinating zygote. The parenchymatous “Gayella-stage” ofRosenvingiella polyrhiza proved to be male and female gametangia, producing spermatozoids and non-motile eggs respectively. Fertile threads were extremely rare in natural material and — contrary toRosenvingiella constricta — did not occur in cultures, so the life cycle could not be elucidated.Prasiola calophylla is frequently associated withRosenvingiella polyrhiza. The life cycle includes heteromorphic asexual generations, the spores of the leafy thallus giving rise to unicellular aplanosporangia.Prasiola furfuracea reproduces only by spores. Samples ofRosenvingiella polyrhiza frequently containPrasiolopsis in addition to a number of other Chlorophyceae. Consequently, it is easy to appreciate that previous investigators came to erroneous conclusions about life histories and biological relations in studies based only on field material.     

Prasiola (Prasiolales,Trebouxiophyceae) in Japan: a survey of freshwater populations and new records of marine taxa

Recent collections from marine and freshwater locations have enabled the investigation of diversity of Prasiola in Japan. Sequence data from the rbc L and tuf A markers revealed the presence of three marine species and one freshwater species. Prasiola delicata was confirmed to occur on Daikokujima, Prasiola calophylla was found for the first time in Japan from Hokkaido, and a species within the P. meridionalis/linearis/stipitata complex was found on both Hokkaido and Daikokujima. Collections from a range of populations of freshwater Prasiola, identified here as P. japonica, were found to be conspecific and identical in rbc L and tuf A sequences to freshwater collections from Nepal, Korea, and China.     

THE PRASIOLALES (CHLOROPHYTA) OF ATLANTIC EUROPE: AN ASSESSMENT BASED ON MORPHOLOGICAL,MOLECULAR, AND ECOLOGICAL DATA,INCLUDING THE CHARACTERIZATION OF ROSENVINGIELLA RADICANS (KÜTZING) COMB. NOV.1

Despite a simple morphology and intensive studies carried out for more than two centuries, the systematics of the Prasiolales still presents several unsolved problems. The taxonomic relationships of several common species of Prasiolales, mostly from northern Europe, were investigated by a combination of morphological observations, culture experiments, and molecular analyses based on rbcL sequences. The results indicate that Rosenvingiella and Prasiola are separate genera. The capacity for production of tridimensional pluriseriate gametangia and the presence of unicellular rhizoids are the morphological features that discriminate Rosenvingiella from filamentous forms of Prasiola. The molecular data indicate that uniseriate filaments can be produced in at least three different species of Prasiola. The genetic diversity of uniseriate filamentous Prasiolales is higher than their simple morphology would indicate, and the provisional retention of Schizogonium Kützing 1843 as independent genus is recommended. The rbcL phylogeny confirms that Prasiola calophylla, P. crispa, and P. stipitata are distinct species, whereas P. stipitata and P. meridionalis are probably conspecific. Rosenvingiella polyrhiza is a strictly marine alga, and most records of Rosenvingiella in Europe are referable to Rosenvingiella radicans, proposed here as a new combination based on Ulothrix radicans Kützing 1849 . This is a primarily terrestrial alga that can occur from upper intertidal rock to locations situated hundreds of kilometers inland. The great confusion that has arisen in Europe between these two species in the last century is mostly due to misidentifications of marine populations of R. radicans.     

Kinetics of pleuridial growth in Antithamnion plumula (Rhodophyceae)

The filamentous and branched thallus of Antithamnion plumula is constitued of two different kinds of branches with apical growth: the cladomial axes with a continuous or indefinite growth, and the pleuridia with a limited growth. The size of the pleuridia depends on their position with respect to the lateral cladomial axes.The growth kinetics of 35 pleuridia were analysed using Nelder's generalized logistics. Each sigmoidal curve, which was divided into four growth stages from the instantaneous acceleration variations, was thus characterized by ten kinetic parameters: lengths at the time of the changes in growth stage, durations of the growth stages and maximum growth rate.The data showed that all curves displayed a marked left dissymmetry which reflected the brevity of the accelerated growth stage (1/5 of total growth duration). The maximum acceleration stage occurs between the individualization of the pleuridial initial cell and the first mitosis. Previously known experimental data were related to this quantitative result so as to put forward a biological meaning. New research pathways were suggested.The kinetic parameters investigated were used for a classification of pleuridia. The smallest ones displayed the slowest growth: they needed twice more time to reach their maximum size than the largest pleuridia whose growth was the fastest. This association of traits was related to the occurrence of acropetal fluxes along the main axis of the thallus.     

Sebdenia cerebriformis sp. nov. (Sebdeniaceae, Sebdeniales) from the south and western Pacific Ocean

A new species of red alga, Sebdenia cerebriformis N'Yeurt et Payri sp. nov. (Sebdeniaceae, Sebdeniales), is described from various localities in the south and western Pacific including Fiji, New Caledonia, the Solomon Islands, Vanuatu, and Indonesia (Java Sea). The new species is characterized by a ruffled thallus with multiple perennial stipitate holdfasts, large conspicuous inner cortical stellate cells, and a lax filamentous medulla.     

Porphyra drewiana, a new species of red algae (Bangiales, Rhodophyta) from Brazil

Porphyra drewiana Coll et Oliveira, sp. nov., is described from plants collected on the south‐east coast of Brazil. The species proposed is monostromatic, monoecious, monoplastidial, without marginal microscopic teeth and does not produce monospores. Both phases, leafy and filamentous, have three chromosomes. Morphologically the most similar species is Porphyra spiralis Oliveira et Coll var. amplifolia Oliveira et Coll, from which it differs by: (i) thallus gross morphology; (ii) scattered pluristromatic areas of vegetative cells; (iii) division of the plastids prior to the nucleus at the first division of the carpospores mother cell; (iv) the number of carpospores and spermatia produced per mother cell; and (v) morphology and behavior of the filamentous phase in cultures. An identification key for the species referred to Brazil is included.     

Genetic diversity and phenotypic variation in marginal populations of the locally endangered speciesHordeum secalinum (Poaceae)

Electrophoresis was used to compare variation in hordein polypeptide patterns and isozymes in five marginal populations ofHordeum secalinum (four Swedish and one Danish population) and four populations along the Atlantic coast from Denmark to Spain. Hordein patterns were uniform within and among Swedish and Danish populations whereas the materials from France and Spain were divergent. The banding patterns for nine isozymes (AAT, IDH, MDH, PGD, GPI, ME, ACP, EST, and PRX) agreed with those reported for otherHordeum species. All putative loci were monomorphic with the exception of PRX, which showed three different phenotypes. The five marginal populations varied in seed set and cultivated plants differed in phenological traits.Dedicated to emer. Univ.-Prof. DrFriedrich Ehrendorfer on the occasion of his 70th birthday     

THALLUS DIFFERENTIATION OF PHOTOSYNTHESIS,GROWTH, REPRODUCTION,AND UV‐B SENSITIVITY IN THE GREEN ALGA ULVA PERTUSA (CHLOROPHYCEAE)1

The chlorophyte Ulva is perceived as a simple and uniform algal form, with little functional differentiation within a thallus. We compared morphology, pigmentation, photosynthesis, growth, reproduction, and UV‐B sensitivity between different thallus regions of Ulva pertusa Kjellman. Thallus thickness and cell size were significantly greater, whereas cell number was less in the basal region than in other regions. Photosynthetic pigment contents were lowest in the basal region and increased toward the marginal region. Photosynthetic capacity and photosynthetic efficiency normalized to fresh weight, area, volume, and cell number showed a progressive increase from the basal to marginal parts; however, on a chl basis those values were equal regardless of thallus part. Values of light saturation point were not statistically different between regions. Growth rates increased from marginal to basal and to middle parts of the thallus, whereas sporulation was highest in marginal (100%) followed by middle (30%) and basal parts (0%). Daily observation over 9 days showed that 56% of the basal cells divided once and did not produce spores, whereas every marginal cell went through its first division and 89% of the primary daughter cells also divided, resulting in 100% sporulation. A 7‐day treatment with PAR and PAR + UV‐A caused a significant decrease in the effective quantum yield of all thallus regions, followed by a recovery toward the initial values, whereas PAR + UV‐A + UV‐B irradiation led to greater photoinhibition and less recovery. Marked differences in the UV‐B sensitivity were observed, with marginal parts being more sensitive and basal parts most resistant.     

Reporter mice express green fluorescent protein at initiation of meiosis in spermatocytes

Transgenic mice were generated using a heat shock protein 2 (Hspa2) gene promoter to express green fluorescent protein (GFP) at the beginning of meiotic prophase I in spermatocytes. Expression was confirmed in four lines by in situ fluorescence, immunohistochemistry, western blotting, and PCR assays. The expression and distribution of the GFP and HSPA2 proteins co‐localized in spermatocytes and spermatids in three lines, but GFP expression was variegated in one line (F46), being present in some clones of meiotic and post‐meiotic germ cells and not in others. Fluorescence activated cell sorting (FACS) was used to isolate purified populations of spermatocytes and spermatids. Although bisulfite sequencing revealed differences in the DNA methylation patterns in the promoter regions of the transgene of the variegated expressing GFP line, a uniformly expressing GFP reporter line, and the Hspa2 gene, these differences did not correlate with variegated expression. The Hspa2‐GFP reporter mice provide a novel tool for studies of meiosis by allowing detection of GFP in situ and in isolated spermatogenic cells. They will allow sorting of meiotic and post‐meiotic germ cells for characterization of molecular features and correlation of expression of GFP with stage‐specific spermatogenic cell proteins and developmental events. genesis 52:976–984, 2014. © 2014 Wiley Periodicals, Inc.     

Changes in the Ultrastructure of Prasiola crispa ssp. antarctica under Salinity Stress

The supralittoral green alga Prasiola crispa, collected in Antarctica, was grown at salinities ranging from 0.35 %o to 175 %o. Its ultrastructure was examined by electron microscopy and compared with the ultrastructure of plants grown under standard conditions (35 %o). The thalli had very thick cell walls, making up approximately 50% of the thallus volume. Most of the protoplast was occupied by a single chloroplast. Numerous starch granules in the chloroplast were enlarged under hypo-osmotic conditions and reduced in volume when subjected to hyperosmotic stress indicating a metabolic shift towards low molecular weight organic osmolytes under the latter conditions. Whilst vacuoles were lacking in plants cultured at salinities between 0.35 %o and 35 %o, they developed under hyperosmotic conditions and possibly may serve as compartments accumulating inorganic ions. Growth, photosynthesis and dark respiration were strongly inhibited under higher salinities, whilst they remained almost unaffected under lower salinities (Jacob et al., 1991).     

Drachiella liaoii sp. nov., a new member of the Schizoserideae (Delesseriaceae,Rhodophyta) from Taiwan and the Philippines

A new member of Delesseriaceae (Ceramiales, Rhodophyta) is described from Southern Taiwan and the Philippines. On the basis of comparative vegetative and reproductive morphology, and phylogenetic analysis inferred from nuclear-encoded large-subunit ribosomal DNA sequences (LSU rDNA), we conclude that it belongs in the genus Drachiella, tribe Schizoserideae, subfamily Phycodryoideae. The new taxon shares with other Drachiella species the absence of macro- and microscopic veins; diffuse growth by marginal and intercalary meristematic cells; a polystromatic, lobed thallus; abundance of rhizoidal marginal proliferations used for attachment; convoluted plastids in surface cells; abundant secondary pit connections among adjacent vegetative cells; large intercellular spaces between surface cells; procarps confined to the upper side of the thallus, circular in outline, consisting of a supporting cell bearing a strongly curved carpogonial branch and two sterile groups that remain undivided; vertical division of gonimoblast initial from auxiliary cell, and unilateral, monopodial branching of gonimoblasts; and mature cystocarps with a massive candelabrum-like fusion cell of fused gonimoblasts bearing carposporangia in branched chains. It is distinguished from the other members of the genus by thalli that consist of extensive tangled mats of prostrate and overlapping decumbent blades, procarps confined to the upper side of the thallus, and the lack of basal stalks or stipes. Whereas the Schizoserideae is predominantly a Southern Ocean tribe, one of the tribe's four genera, Drachiella, was known only from the eastern Atlantic and Mediterranean. We herein report the first record of the genus for the Indo-Pacific Ocean, and describe Drachiella liaoii, sp. nov., as a fourth species in the genus.     

Effects of plant growth regulators and culture medium on morphogenesis of Solieria filiformis (Rhodophyta) cultured in vitro

Morphogenesis and plant regeneration were analyzed in axenic tissueculture of the red alga Solieria filiformis (Kützing)Gabrielson. Thallus segments cultured in ASP 12-NTA synthetic medium showedgrowth of filaments formed by divisions of cortical, subcortical and medullarycells (filamentous explants), whereas in seawater enriched with Von Stosch'ssolution, thallus segments developed branches. Filamentous explants were abletoregenerate plants when transferred from a solid to a liquid medium. Plantregeneration was significantly promoted by treatment with plant growthregulators on filamentous explants formed from intercalary segments, up to 67plantlets per explant in treatments with 6-benzylaminopurine (5.0 mgl^–1), in contrast to three plantlets in controlslackingplant growth regulators. These adventitious plantlets developed into plantsmorphologically similar to those originated from germinating spores. Theseresults indicate that plant growth regulators play a role on the regulation ofmorphogenesis, and could be useful for micropropagation of colloid-producingredalgae.     

Differentiation of perennial and annual types due to habitat conditions in the wild riceOryza perennis

Populations of the common wild rice of AsiaO. rufipogon Griff. (=Oryza perennis Moench) were studied with regard to interrelations between life-history traits and habitat conditions. They showed a perennial-annual continuum and differed in reproductive allocation and many other traits. Perennial populations were found in deep swamps, while annual populations were in shallower, temporary swamps which were parched in the dry season. The perennial and annual types tended to be in association with other perennial and annual plants, respectively, suggesting their niche differentiation. Intermediate perennial-annual populations were in communities with a high species diversity. In one population, plants growing on the periphery of the swamp were of annual and those in deeper center were of perennial type. Another population seemed to be differentiated into an annual and an intermediate type in accordance with different degrees of habitat disturbance. The small genetic distances found between the sub-populations suggested their differentiation within a gene pool.Contribution from National Institute of Genetics, Japan, No. 1415.     

Sur le développement des spores et la formation du thalle rampant de Kallymenia microphylla J. Ag. (Rhodophyceae,Cryptonemiales)

Abstract

On the spore development and the growth of Kallymenia microphylla J. Ag. (Rhodophyceae, Cryptonemiales) creeping thallus. — The filamentous creeping axis produced by spore grows into a terminal cell and then branches out into a monostratified creeping thallus looking like a disc. This creeping thallus is looking exactly like that of the Rhodocorton haucki (Schiffner) Hamel. Compared to the other species of Kallymenia, we find out that this creeping thallus has cellular fusions as well; they are more frequent and appear quite early here.     

Myxomycetes from orissa (india) II

Summary Six myxomycetous fungi,Arcyria denudata (Linn.)Wettstein,Arcyria cinerea (Bull.)Pers.,Hemitrichia stipitata (Massee)Macbr.,Diachea leucopodia (Bull.)Rost.,Stemonitis splendens Rost. andPhysarum nicaraguense Macbr. have been figured and described from Cuttack, Orissa.     

Interaction between the macrophyte <Emphasis Type="Italic">Stratiotes aloides</Emphasis> and filamentous algae: does it indicate allelopathy?

The aquatic macrophyte Stratiotes aloides Linnaeus, which has recently received attention in studies on allelopathy, has been shown to suppress phytoplankton growth. In the Netherlands, S. aloides often co-occurs with floating filamentous algae. However, filamentous algae are generally absent in close proximity to S. aloides, resulting in gaps in filamentous algae mats. We analyzed whether those gaps may be caused by allelopathic substances excreted by S. aloides or by nutrient depletion. We studied in a field survey the colonization of natural S. aloides by filamentous algae and determined in situ nutrient concentrations in natural S. aloides stands. To analyze the relative importance of allelopathy and nutrient competition in the interaction between S. aloides and filamentous algae, we carried out field experiments. Introduction of artificial (non-allelopathic) plants in natural S. aloides stands enabled us to compare the colonization by filamentous algae of both Stratiotes sp. and artificial plants. The filamentous algae were absent in close vicinity to S. aloides. Significantly lower concentrations of ortho-phosphate and potassium were observed close to S. aloides as compared with the filamentous algae. In the field experiments the artificial plants were rapidly colonized by filamentous algae, mainly Cladophera Kützing and Spirogyra Link, while all natural plants remained free of such algae. Additionally, most nutrient concentrations did not significantly differ in the proximity of artificial or natural stands of S. aloides. The concentrations of the major growth-limiting nutrients, phosphate and nitrate, were significantly higher and nonlimiting in natural Stratiotes stands. Our main conclusion is that, although allelopathic interactions between S. aloides and filamentous algae do occur under natural conditions, nutrient competition between the two can also be an important factor.     

Selective elimination of perennial ryegrass by activation of a pro-herbicide through engineering <Emphasis Type="Italic">E. coli argE</Emphasis> gene

Perennial ryegrass is widely used for overseeding dormant bermudagrass on golf courses and sports fields in Southeastern United States to provide green color and improved playability. Late spring and summer persistence of perennial ryegrass may decrease the quality of the bermudagrass turf and reduce its winter hardiness. To help solve this problem, we developed a strategy to activate a pro-herbicide within the transgenic perennial ryegrass plants and to cause self elimination of the plants. An E. coli argE gene was introduced into perennial ryegrass by the biolistic method, which resulted in four independently transformed green plants. The mRNA of argE gene was detected in three of the plants by RT-PCR. Perennial ryegrass plants expressing the argE transgene were selectively controlled upon application of a pro-herbicide, N-acetyl-l-phosphinothricin (or N-acetyl-PPT), since the N-acetylornithinase encoded by argE gene is able to convert N-acetyl-PPT to the herbicide phosphinothricin (PPT). The non-transgenic bermudagrass plants were unaffected by the treatment. This approach provides a means to selectively remove a group of transgenic plants without affecting other plants growing with them.     

Preference and Performance in Plant–Herbivore Interactions across Latitude–A Study in U.S. Atlantic Salt Marshes

High-latitude plants are often more palatable to herbivores than low-latitude conspecifics. Does increased plant palatability lead to better herbivore performance? Our field and laboratory work investigated (A) whether high-latitude plants have traits indicating that they should be higher-quality foods for herbivores; (B) whether geographic differences in plant quality are more important than local adaptation of herbivores. We studied 3 plant species and 6 invertebrate herbivores in U.S. Atlantic Coast. Past studies had shown high-latitude individuals of these plants are more palatable than low-latitude conspecifics. We documented plant traits and herbivore performance (body size) in the field across latitude. We collected individuals from different latitudes for factorial (plant region x herbivore region) laboratory experiments, examining how herbivore performance was affected by plant region, herbivore region, and their interaction (i.e., local adaptation). Field surveys suggested high-latitude plants were likely of higher quality to herbivores. Leaf nitrogen content in all plant species increased toward high latitudes, consistent with lower leaf C/N and higher leaf chlorophyll content at high latitudes. Furthermore, leaf toughness decreased toward higher latitudes in 1 species. The body size of 4 herbivore species increased with latitude, consistent with high-latitude leaves being of higher quality, while 2 grasshopper species showed the opposite pattern, likely due to life-history constraints. In the laboratory, high-latitude plants supported better performance in 4 herbivore species (marginal in the 5th). The geographic region where herbivores were collected affected herbivore performance in all 6 species; however, the pattern was mixed, indicating a lack of local adaptation by herbivores to plants from their own geographic region. Our results suggest that more-palatable plants at high latitudes support better herbivore growth. Given that geographic origin of either plants or herbivores can affect herbivore performance, the nature of plant-herbivore interactions is likely to change if climate change “reshuffles” plant and herbivore populations across latitude.     

Development of areolae and growth of the peripheral prothallus in the crustose lichen Rhizocarpon geographicum: an image analysis study

Areolae of the crustose lichen Rhizocarpon geographicum (L.) DC., are present on the peripheral prothallus (marginal areolae) and also aggregate to form confluent masses in the centre of the thallus (central areolae). To determine the relationships between these areolae and whether growth of the peripheral prothallus is dependent on the marginal areolae, the density, morphology, and size frequency distributions of marginal areolae were measured in 23 thalli of R. geographicum in north Wales, UK using image analysis (Image J). Size and morphology of central areolae were also studied across the thallus. Marginal areolae were small, punctate, and occurred in clusters scattered over the peripheral prothallus while central areolae were larger and had a lobed structure. The size-class frequency distributions of the marginal and central areolae were fitted by power-law and log-normal models respectively. In 16 out of 23 thalli, central areolae close to the outer edge were larger and had a more complex lobed morphology than those towards the thallus centre. Neither mean width nor radial growth rate (RaGR) of the peripheral prothallus were correlated with density, diameter, or area fraction of marginal areolae. The data suggest central areolae may develop from marginal areolae as follows: (1) marginal areolae develop in clusters at the periphery and fuse to form central areolae, (2) central areolae grow exponentially, and (3) crowding of central areolae results in constriction and fragmentation. In addition, growth of the peripheral prothallus may be unrelated to the marginal areolae.