Thallus Color Research Articles

Functional traits of non-vascular epiphytes influence fine scale thermal heterogeneity under contrasting microclimates: insights from sub-Mediterranean forests

Abstract Lichens and bryophytes contribute to regulating the forest microclimate and support ecosystem functions. Exploring the thermal heterogeneity at a trunk-level may help elucidate the effect of thermoregulation of epiphytes. We hypothesized that (i) the thermal patterns of epiphytic communities depend on the microclimatic conditions of the surrounding atmosphere and (ii) the thermal heterogeneity at a trunk-level may in turn depend on functional traits of epiphytic communities, such as thallus colour and growth form. We carried out two measurement sessions under contrasting microclimatic conditions (wet vs. dry). Using a thermal camera, we acquired infra-red (IR) images of 50 trees during the same time period under the contrasting wet and dry conditions. Results showed significant differences in thermal characteristics of the trees when contrasting wet with dry conditions and that colour and growth form were significantly associated with changes in thermal patterns at the trunk-level. The study highlights the importance of understanding the thermoregulatory processes of epiphytic communities.

Lethal effects of the harmful dinoflagellate Karenia selliformis (Gymnodiniales, Dinophyceae) on two juvenile kelp sporophytes Saccharina japonica and S. sculpera (Laminariales, Phaeophyceae)

A huge red tide caused mainly by Karenia selliformis in the eastern Hokkaido Pacific Ocean during autumn of 2021 was associated with mass mortalities of sea urchins, salmon, and other marine organisms. Bleaching of seaweeds, including kelps, was reported in the areas with red tide. Thus, K. selliformis is suspected to be harmful to kelp; however, the harmful effects are not yet known. This study aimed to verify the harmfulness of K. selliformis to cultured juvenile sporophytes of two commercially valuable kelp species, Saccharina japonica and Saccharina sculpera. Juvenile kelp sporophytes were exposed to seawater with four different densities of red tide-causing K. selliformis (0, 200, 1000, 2000 cells mL−1), and changes in thallus color over time were examined. Some thalli of both kelps were visibly bleached within 12 h of K. selliformis exposure; no thallus of the negative control was bleached. The ratio of bleached thalli differed significantly depending on the density of K. selliformis and kelp species; S. japonica was more sensitive than S. sculpera. During the follow-up period, most bleached thalli, especially those exposed to high-density K. selliformis seawater, finally withered. The median lethal density (LD50) of K. selliformis within 144 h after 48 h exposure was estimated as 218 cells mL−1 and 2285 cells mL−1 for juvenile thalli of S. japonica and S. sculpera, respectively. These results suggested the lethal effects of K. selliformis to kelp leaves, suggesting the potential risk posed to cultured and natural kelp communities by K. selliformis red tides.

Ethyl methanesulfonate mutant library construction in Neopyropia yezoensis to provide germplasm resources for next-generation genome-selection breeding

With the development of the laver industry, germplasm depression has become a serious issue, and current cultivars cannot adapt to different aquaculture regions. In order to increasing the genetic diversity and developing more germplasm sources, it is urgent and reasonable to construct a mutant library with more new germplasms. In this research, a mutant library was constructed by ethyl methanesulfonate (EMS)-mutagenized archeospores, and the most optimal treatment procedure was determined by performing different mutagen concentrations (2.25%) and treatment times (30 min). A total of 1860 haploid thalli were produced as the M1 mutant population and further cultured into conchocelis clones for the reservation of germplasm resources. Among these, 667 individual thalli were evaluated for their phenotypic traits, including thallus length, thallus width, length/width, thallus shape, photosynthesis ability, thallus color, thallus margin, and specific growth speed. The mutation frequency of the length/width ratio was 17.39%, Fv/Fm and NPQ were 21.84% and 29.35%, respectively, and SGR was 13.59%. The mutation frequency of thallus color was 0.91%. This work may not only provide a basic practical reference guide for EMS-based mutant library construction for other seaweeds but, more importantly, also serve as a valuable resource for functional genomics research and laver breeding.

Determination of nitrogen content in Ulva fenestrata by color image analysis – a rapid and cost-efficient method to estimate nitrogen content in seaweeds

There is an increasing interest in the cultivation of seaweeds for food and feed, and the seaweed aquaculture industry is rapidly developing. The nutritional status of the seaweeds is important to ensure a good quality crop. Cost-efficient and straightforward methods for farmers to analyze their crop are essential for the successful development of the industry. In this study, we developed non-destructive, labor- and cost-efficient models to estimate the nitrogen content in the crop seaweed Ulva fenestrata by color image analysis. We quantified tissue nitrogen content and thallus color in sea-farmed seaweed every week throughout a whole cultivation season (15 consecutive weeks) and analyzed data with linear regression models. We showed that color image analysis accurately estimated the nitrogen content in the seaweed (R2 = 0.944 and 0.827 for fresh tissue and dried powder, respectively), and through tenfold cross validation we showed that the developed models were robust and precise. Based on these models, we developed a web-based application that automatically analyzes the nitrogen content of U. fenestrata. Furthermore, we produced a color guide that can easily be brought to the farm for onsite crude estimation of the nitrogen content of U. fenestrata. Our results demonstrate that color can be a powerful tool for seaweed farmers (and researchers) to estimate seaweeds’ nutritional status. We anticipate that similar models can be developed for other commercially interesting seaweed species.

LICHEN SEBAGAI BIOINDIKATOR KUALITAS UDARA DI KECAMATAN JEBRES KOTA SURAKARTA

Surakarta is a city with polluted air due to transportation activities. Utilization of bioindicators could be one of efforts to monitor air pollution. Lichen is one of the air quality bioindicators that can be observed based on its morphological characteristics. This study aimed to determine air quality using lichen bioindicators at two stations in the Jebres sub-district, namely on UNS street and Juanda street. These two locations have different environmental characteristics and traffic density. This study is a descriptive exploratory research using purposive sampling method. The collected data were analyzed qualitatively based on the morphological characteristics of the lichen found. The results showed that nine species of lichen found in UNS street area, while five species of lichen in Juanda street area. Apparently, morphological character of lichen consisted of crustose, leprose, and foliose thallus types with bright thallus colour, larger diameter, and more individuals, whereas in Juanda street is crustose and leprosy with a duller color, smaller diameter, and fewer individuals. In fact, the vehicle density in the area of Juanda street was higher than UNS street area. As it is largerly known that the type and morphology are influenced by the environmental quality. Therefore, based on the founded lichen’s type and morphology, the area of Juanda street was likely more polluted than UNS street area. Our finding suported that lichen could be bioindicator for air quality.

Riccia anatolica sp. nov. a new liverwort (Ricciaceae) species from Turkey

Riccia anatolica sp. nov. is described and illustrated as a new species from Tarsus-Mersin in the southern part of Turkey. The new species is morphologically similar to some common Turkish (R. nigrella and R. trabutiana) and Middle Eastern (R. okahandjana and R. congoana) Riccia species. It can be distinguished from two Riccia species with shiny black scales that occur in Turkey—R. nigrella and R. trabutiana- by the two layered epidermis, plant size, spores and thallus colour.

Two new Bacidina species (Lecanorales, Ascomycota) from Pakistan


 
 
 Bacidina margallensis and B. iqbalii from Pakistan are described and illustrated. Phylogeny of ITS nrDNA region confirms their position within the genus Bacidina, and morphological data make them distinct from other known species of the genus. Based on molecular data, corticolous Bacidina margallensis appears to be a sister species to B. chloroticula, but morphologically, when dry, is the most similar to known from Europe B. mendax because of the granular and warted greenish grey thallus, whitish-cream to dark brown and often piebald apothecia. It differs from that species by shorter, wider and less septate ascospores; 1–3-septate in B. margallensis vs 3–5(6)-septate in B. mendax, and by unusual parrot-green colour of wet thallus. Saxicolous Bacidina iqbalii is closely related to B. neosquamulosa but differs in having crustaceous thallus, transculent when wet entirely pale apothecia, larger asci and less septate large ascospores.
 
 

Phenotypic plasticity and taxonomy of Cladophora gracilis (Griffiths) Kützing (Cladophorales, Chlorophyta) in the western Yellow Sea with the implication of its DNA barcode

Due to extensive morphological plasticity, the taxonomy of Cladophora species remains unclear. As one of the widely distributed species, C. gracilis was reported to hold many varieties, which make it difficult to identify the species. This study explored the morphology diversity of nine C. gracilis samples collected along the coast of western Yellow Sea. Some samples showed extremely varied characteristics, by which one cannot classify them correctly. Hence, 18S rDNA and nuclear ribosomal DNA internal transcribed spacer regions (ITS) sequences were employed to delimit species. For 18S rDNA, sequence similarity ranged from 99.6% to 100%. For ITS region, the similarity ranged from 98.7% to 100%. Molecular data strongly suggested that the morphologically heterogeneous samples were actually the same species. Characteristics comparison of the samples revealed that the taxonomy criteria including branching pattern and density, thallus color, height and texture varied widely, influenced by environmental conditions and age of alga. Besides, cell dimensions, as the relatively stable criterion, also exhibited intraspecific variance. Successful application of 18S rDNA and ITS sequences indicated that molecular method can be a powerful assistant as DNA barcodes to traditional morphology taxonomy.

Application of a programmed semi-automated Ulva pertusa bioassay for testing single toxicants and stream water quality

A toxicity test based on inhibition of reproduction in the green macroalga Ulva pertusa involves quantifying the change in thallus color as reproduction progresses. However, interpretation of this color change is reliant on the skill level of the examiner. This study aimed to validate a new toxicity test based on inhibition of reproduction in the green macroalga U. pertusa using a vital stain and programmed semi-automated analysis (using Image J) of the change in thallus color. The toxicity rank by inverse EC50 values was: irgarol (0.048 mg L−1) > Ag (0.132 mg L−1) > As (0.172 mg L−1) > simazine (0.378 mg L−1) > formaldehyde (0.442 mg L−1) > DCOIT (0.783 mg L−1) > ZnPT (3.556 mg L−1) > medetomidine (11.600 mg L−1) > phenol (29.316 mg L−1) > methanol (2,736 mg L−1) > ethanol (3,306 mg L−1). The sensitivity of the U. pertusa test to stream waters was similar to or lower than those of the commonly-used Lemna minor and Daphnia magna bioassays. The U. pertusa bioassay is sensitive to, and suitable for, testing various toxicants including metals, volatile organic compounds, herbicide, antifouling agents and phenol and can also be applied to testing freshwater quality after salinity adjustment.

Psoroma nivale (Pannariaceae, lichenized Ascomycota) a new species with dark, elongate squamules and bacilliform ascospores from arctic Québec, Canada

AbstractThe new species Psoroma nivale is described from an area of late snow-lie in the Keglo Bay area on the eastern side of Ungava Bay, northern Québec, Canada. It is superficially similar to P. hypnorum but has a dark, brownish black thallus colour without reddish hues, much-branched, proliferating squamules, thick paraphyses, distinct but inconspicuous IKI+ ascus tube structures, and characteristic elongate, bacilliform, often asymmetrical ascospores. The new species is compared with possible related taxa and its systematic position discussed. A key to the species of pannarioid lichens reported from arctic areas of North America is also provided.

Dehydration-induced changes in spectral reflectance indices and chlorophyll fluorescence of Antarctic lichens with different thallus color, and intrathalline photobiont

In this study, we investigated responses of the Photochemical Reflectance Index (PRI), and Normalized Difference Vegetation Index (NDVI) to gradual dehydration of several Antarctic lichen species (chlorolichens: Xanthoria elegans, Rhizoplaca melanophthalma, Physconia muscigena, cyanolichen: Leptogium puberulum), and a Nostoc commune colony from fully wet to a dry state. The gradual loss of physiological activity during dehydration was evaluated by chlorophyll fluorescence parameters. The experimental lichen species differed in thallus color, and intrathalline photobiont. In the species that did not exhibit color change with desiccation (X. elegans), NDVI and PRI were more or less constant (mean of 0.25, − 0.36, respectively) throughout a wide range of thallus hydration status showing a linear relation to relative water content (RWC). In contrast, the species with apparent species-specific color change during dehydration exhibited a curvilinear relation of NDVI and PRI to RWC. PRI decreased (R. melanophthalma, L. puberulum), increased (N. commune) or showed a polyphasic response (P. muscigena) with desiccation. Except for X. elegans, a curvilinear relation was found between the NDVI response to RWC in all species indicating the potential of combined ground research and remote sensing spectral data analyses in polar regions dominated by lichen flora. The chlorophyll fluorescence data recorded during dehydration (RWC decreased from 100 to 0%) revealed a polyphasic species-specific response of variable fluorescence measured at steady state—Fs, effective quantum yield of photosystem II (ΦPSII), and non-photochemical quenching (qN). Full hydration caused an inhibition of ΦPSII in N. commune while other species remained unaffected. The dehydration-dependent fall in ΦPSII was species-specific, starting at an RWC range of 22–32%. Critical RWC for ΦPSII was around 5–10%. Desiccation led to a species-specific polyphasic decrease in Fs and an increase in qN indicating the involvement of protective mechanisms in the chloroplastic apparatus of lichen photobionts and N. commune cells. In this study, the spectral reflectance and chlorophyll fluorescence data are discussed in relation to the potential of ecophysiological processes in Antarctic lichens, their resistance to desiccation and survival in Antarctic vegetation oases.

Isolation and Identification of Dominant N2 Fixing Cyanobacterial Strains from Different Locations

Isolation of cyanobacteria dominated in the soil samples collected from different sites in Kafr El- Sheikh, and El-Dkahlia governorates isolates were successfully obtained as bacterial free cyanobacteria. They were identified cyanobacteria was carried out using the following: thallus color, thallus morphology and size of heterocyst, vegetative and reproductive cells. Heterocyst-forming cyanobacteria were also cultured as Anabaena sp., Nostoc sp., Oscillatoria sp., and Chroococcus sp. Nostoc sp . were isolated at high frequency; Nostoc sp. and Anabaena sp. isolates representing in kafr El-Sheikh and El-Dakahlia Governorates. Less frequency of cyanobacteria belonging to different genera namely Oscillatoria sp. and Chroococcus sp. Nostoc spp.were recorded highest amount of fixed nitrogen and mass production with in increasing incubation period of interacellular and /or extracellular nitrogenfixation. While,the most active strains for nitrogenase activity were Nostoc mucorum K and Anabaena oryzae D.

­Molecular identification of Audouinella-like species (Rhodophyta) from China based on three short DNA fragments

Four algal specimens with morphological resemblance to Audouinella were collected in China, both bluish and reddish thalli included. Because of the taxonomic obscurity of the acrochaetioid lineage, a molecular phylogenetic analysis was performed to verify the phylogenetic position of these specimens based on three short DNA fragments including psbA, UPA and COI-5P. Molecular sequences were analyzed by neighbor-joining, maximum likelihood, Bayesian, and NeighborNet methods. Phylogenetic relationships based on three DNA fragments were consistent in that the four Audouinella-like thalli clustered together with Thorea hispida (Thore) Desvaux with strong support. The four specimens morphologically similar to Audouinella were concluded to represent the chantransia stage of Thoreales based on molecular trees. The reddish specimen shared no sequence divergence with the bluish ones. For identification of freshwater Audouinellla, criteria of thallus color must be used with caution and molecular tool-assisted analysis are essential. The formerly established new species Audouinella heterospora S.L.Xie & Y.J.Ling was inferred to be synonymous with the chantransia stage of T. hispida. The three DNA molecular markers demonstrated to be effective to ascertain the phylogenetic position of acrochaetioid algae specimens, and to delineate other freshwater Rhodophyta.

ETNOLICHENOLOGY OF OLD MENS BEARD (Usnea spp) AT PRIANGAN

<p>Usnea has been used for a long time in Indonesia for traditional medicine and crude material for jamu. The study of taxonomy and local knowledge at Priangan are less information. The research was conducted between March 2011–April 2012. The aim of this research was to explore the local knowledge of species Usnea conducted by emic and ethic approaches. The specimens collection was done by survey along the pine forest at Bandung, Sumedang, Garut, Ciamis and Tasikmalaya in Priangan areas. The specimens were analysis morphological, anatomy and chemical. The etnolichenology study was done by descriptive qualitative, survey and interview also observation participative at Gunung Gelap Village and Kamojang area of Garut Regency and Cibunar village,Sumedang Regency in West Java. The interview was done with key informants. The taxonomical study found the 11 species of Beard lichens found in pine forest at Priangan, belong to 3 subgenus. They are subgenus Dilichousnea, consist of Usnea filipendula, U. hirta,U. longisima and U. trichodea. Subgenus Eumitra consist of U.baileyi and U. ceratina. Subgenus Usnea consist of U. cornuta, <br />U. flexilis, Usnea. flexuosa, U. florida and U.glabra. The dominant species growing on pine in different location are U. baileyi and U. flexilis. They have thalli colour dark green, yellow-green, pale green and reddish brown. Thallus branching is dichotomous in all species with difference in the thickness form the isotomic or anisotomic dichotomous types. Species Usnea is fructicose with habits erect type or subpendent type or pendent type.The lichenic acid contain in Usnea species are different and dominant by usnic acid and protocetoric acid. The stictic acid only found in U.flexuosa. The result of interview known that Usnea was called janggot kai by the Sundanese. People grouping the Usnea based on colour, growth pattern and surface of thallus, so known “Janggot kai hejo, janggot kai koneng, janggot kai rubak, janggot kai ngaruntuy, janggot kai kesrak and janggot kai lemes”. Mostly the people used Usnea as raru for preservative nira, medicine and spices. The Sudanese used Usnea in formula oj jamu or ubar kampong to treat mouth ulcer, dysentery, catch a cold, skin eruption, stiff, menstruation painful, hemorrhoids,child birth ease and in making mahinum (jamu for mother after utter) and used as face powder of noble woman.</p><p><br /><strong>Keywords</strong>: Usnea, local knowledge, raru, ubar kampong.</p>

Can thallus color of red algae be used as an environmental indicator in shallow waters?

Red algae sometimes turn yellow, but few studies have been conducted on the yellowing of subtidal bed-forming species and on the relationship between the color and environmental factors. We examined the seasonal changes in thallus color of macroscopic subtidal red algae and nutrient levels as in shallow waters at two sites: Hirasawa (0 to 3 m in depth) and Okinoshima Island (0 to 6 m in depth), central Pacific coast of Japan from April 2011 to March 2012. Yellowed red algae were found at all depths of the two sites. At Hirasawa, the ratio of yellowed species among the red algae (yellowing ratio, YR) calculated with data on a total of 23 species (3 to 14 species month−1) was high in months in which nitrate nitrogen (NO3-N) was low (1.73 to 2.19 μmol L−1); in months with higher NO3-N (5.91 to 6.01 μmol L−1), YR was 0 but exceptionally high in April probably because of the duration of fine days. At Okinoshima Island, YR calculated with data on a total of 40 species (3 to 22 species month−1) was high from March to July (except May), in which NO3-N was low (0.93 to 2.16 μmol L−1), but low from October to February among the months with higher NO3-N (4.56 to 5.62 μmol L−1). Totally, YR was negatively correlated with nitrate concentrations and NO3-N, which supports the possibility to use the value of YR as an indicator of nitrogen level although attention should also be paid to light conditions.

Iron localization inAcarosporacolonizing schist on Signy Island

AbstractA small, inconspicuous lichen,Acarosporacf.badiofusca, was discovered colonizing iron-stained quartz mica schists on the lower slope of Manhaul Rock, a recently exposed nunatak on the McLeod Glacier, Signy Island, South Orkney Islands. Thallus colour ranged from rust on exposed rock surfaces to paler orange and green in shaded crevices. This study addressed the hypothesis that colour reflects element localization, and considered substance localization within lichen tissues and responses to stress. Electron microprobe analysis of specimens confirmed that Fe is localized principally in the outer rust-coloured part of the cortex, confirming that the colour reflects Fe localization. Oxalates, widely reported as contributing to tolerance mechanisms to environmental stress, were not detected using X-ray diffraction. The upper thallus surface consisted of sub-micron particulate phases containing Fe, Al and O, suggesting mixed oxide/hydroxide phases are present and play a role in photoprotection.

Morphological and molecular evidence placesMaroninainto synonymy withProtoparmelia(Ascomycota:Lecanorales)

AbstractThe phylogenetic placement of the genusMaroninawas studied, based chiefly on phenotypic characters such as thallus colour and anatomy, secondary chemistry, the anatomy of the excipulum and the ascus-type. DNA sequence data of mitochondrial and nuclear ribosomal loci from some of the species support the hypothesis thatMaroninais nested withinProtoparmelia. Hence,Maroninais reduced to synonymy withProtoparmelia. Comparison of genetic distances suggests that the two varieties withinM. orientalisshould be regarded as distinct species. Consequently, the new combinationsProtoparmelia australiensis(Hafellner & R. W. Rogers) Kantvilaset al., P. corallifera(Kantvilas & Papong) Kantvilaset al.,P. hesperia(Kantvilas & Elix) Kantvilaset al., P. multifera(Nyl.) Kantvilaset al., andP. orientalis(Kantvilas & Papong) Kantvilaset al. are proposed.

A molecular study of Mazzaella (Gigartinaceae, Rhodophyta) and morphological investigation of the splendens clade from Pacific North America

Hughey J.R. and Hommmersand M.H. 2010. A molecular study of Mazzaella (Gigartineaceae, Rhodophyta) and morphological investigation of the splendens clade from Pacific North America. Phycologia 49: 113–135. DOI: 10.2216/08-68.1The delineation of species of Mazzaella remains problematic because of similarities in thallus shape and color. To better define species boundaries, molecular phylogenetic analyses and developmental studies of Mazzaella were performed on one of the more taxonomically challenging clades, the splendens group (Mazzaella flaccida, Mazzaella linearis, Mazzaella sanguinea and Mazzaella splendens). Using an expanded rbcL data set, internal transcribed spacer sequences, and a combined analysis, six clades were identified: splendens, californica, rosea, cobinae, oregona, and South American/African. Morphological examination of members of the splendens clade identified differences in their cystocarpic and tetrasporangial development and supported the recognition of two subspecies, M. splendens subsp. splendens and M. splendens subsp. fulgens Hughey & Hommersand stat. nov. The gonimoblasts of M. flaccida, M. linearis and M. sanguinea produced numerous terminal tubular cells that radiated from the gonimoblasts and fused to gametophytic cells; whereas, tubular gonimoblast cells were rare in M. splendens subsp. splendens and absent in M. splendens subsp. fulgens. The development of gonimoblasts was associated with the production of secondary gametophytic filaments derived from inner cortical and medullary cells. Their formation was progressive, continuing beyond the edges of the radiating gonimoblasts and giving rise to cystocarps of indefinite dimensions (M. flaccida and M. splendens subsp. splendens), or they developed primarily before the production of gonimoblasts from an auxiliary cell resulting in cystocarps of more or less definite size (M. linearis, M. sanguinea and M. splendens subsp. fulgens). The secondary filaments persisted, leaving a well-defined involucre (M. splendens subsp. fulgens), a poorly defined involucre (M. linearis) or were completely digested at maturity (M. splendens subsp. splendens), sometimes leaving a halo (M. sanguinea). Tetrasporangia were produced in secondary medullary filaments that formed lateral bands on both sides of the blade (most species) or extended across the center of the medulla (M. splendens subsp. fulgens). The tetrasporangia differentiated in sori within these bands and consisted of short filaments that reconnect by secondary pit connections forming loops.

Three species of Mastophora (Rhodophyta: Corallinales, Corallinaceae) in the tropical Indo-Pacific Ocean: M. rosea (C. Agardh) Setchell, M. pacifica (Heydrich) Foslie, and M. multistrata sp. nov.

Keats D.W., Maneveldt G.W., Baba M., Chamberlain Y.M. and Lewis J.E. 2009. Three species of Mastophora (Rhodophyta: Corallinales, Corallinaceae) in the tropical Indo-Pacific Ocean: M. rosea (C. Agardh) Setchell, M. pacifica (Heydrich) Foslie, and M. multistrata, sp. nov. Phycologia 48: 404–422. DOI: 10.2216/08-101.1.Three species of Mastophora (Corallinaceae, Corallinales, Rhodophyta) were found in extensive studies of non-geniculate coralline algae in various areas of the tropical Indo-Pacific, including French Polynesia, Fiji, Ryukyu Islands (Japan), and Taiwan. Two species are delicate and leafy but are distinguishable on morphological grounds. Mastophora rosea plants are taeniform, dichotomously branched, and weakly calcified and have rolled margins. Their thalli show very little secondary growth, with only occasional small round patches at the surface. Tetrasporangial and carposporangial conceptacles are very high (330–640 μm) and dome-shaped to almost spherical. Mastophora rosea plants collected during this study stand out in the water because of their bluish-purple colour. Mastophora pacifica has more strongly calcified thalli that are irregularly branched, with abundant secondary growth and the development of loosely attached, crispy layers. Tetrasporangial and carposporangial conceptacles are conical (280–550 μm high). Thallus colour in M. pacifica varies substantially depending on where it is growing, ranging from violet brown to dark red to greyish ruby, but are mostly pale-pink to reddish-purple in their submerged living state. Mastophora multistrata sp. nov. plants are hard and robust. Their thalli are made up of tightly packed layers that are evident only in section. Tetrasporangial conceptacles are generally low (315–490 μm high) and dome-shaped. In their living state, M. multistrata plants are usually deep-purple plum coloured.

Rapid assessment of tissue nitrogen in cultivated Gracilaria gracilis (Rhodophyta) and Ulva lactuca (Chlorophyta)

Tissue nitrogen content and thallus colour were quantified using a rapid assessment method based on the Pantone® matt uncoated formula guide for raft-cultivated Gracilaria gracilis Steentoft, Irvine ef Farnham at Saldanha Bay and tank-cultivated Ulva lactuca Linnaeus at Jacobsbaai in 2001–2002. For Gracilaria a relationship between thallus colour and tissue nitrogen, as well as a transition between green-yellows and yellow-browns that occurs between 0.8 and 1.3 mg N per g tissue (Pantone® colours 460U-455U), was found, with the green-yellow colours indicating nitrogen-starved material and the yellow-browns indicating nitrogen-replete material. For Ulva a transition between green-yellow and green occurred at a tissue nitrogen content of between 1.5 and 1.7 mg N per g tissue (Pantone® colours 585U-583U). This relationship can be used by seaweed farmers for cultivation management as a quick guide to determine nutritional status of the seaweeds, and as an indication of protein content when the seaweeds are used as feeds.