Distribution and symptoms of epiphyte infection in major carrageenophyte-producing farms

High density commercial farming of carrageenophyte Kappaphycus alvarezii is often plagued with “ice-ice” disease and epiphyte infection, which eventually leads to reduced production and in some cases collapse of crop. Epiphyte outbreak has been occurring regularly in major carrageenophyte farms in the Philippines, Indonesia, Malaysia and Tanzania. Infected materials from these countries were studied to establish baseline information on the epiphyte’s identity, density, symptoms and secondary infection on the host seaweed. The causative organism was identified as Neosiphonia apiculata (Hollenberg) Masuda et Kogame, based on its morphological features. Epiphyte density on host seaweed materials decreased in the following order: the Philippines (88.5 epi cm⁻²), Tanzania (69.0 epi cm⁻²), Indonesia (56.5 epi cm⁻²) and Malaysia (42.0 epi cm⁻²). Initial symptoms were the presence of tiny black spots, indicating the embedded tetrasporeling in seaweed cortex layer. Vegetative form emerged after 2 weeks measuring less than 0.5 mm in length with a density of less than 25.0 epi cm⁻². Upon maturation, infected seaweed takes on a “hairy” appearance with “goose-bumps” like cortical swellings. The epiphyte appears as a solitary plant with multiple secondary rhizoids or as multiple epiphytes appearing from a single cortical opening. At the end of infection, the epiphytes left dark pits on the cortical swelling, and the carrageenophytes are infected by opportunistic bacteria. Bacterial enumeration of healthy and infected seaweed materials showed an increase of more than 300% in total bacterial count on infected materials dominated by Alteromonas sp., Flavobacterium sp. and Vibrio sp.     

Hypoosmotic volume regulation in the sea anemone metridium senile

1. The anemone Metridium senile survives salinities from seawater (950 mOsm) to 55% SW (520 mOsm) for at least two weeks. Animals exposed to 40% SW (380 mOsm) die within three days.2. The tissue amino acid content of M. senile acclimated to 950 mOsm, 807 mOsm, 665 mOsm and 520 mOsm for two weeks is respectively, 444, 382, 331 and 251 μmol/g dry wt. A decrease in the concentration of taurine accounts for nearly all of the decrease in the free amino acid pool.3. Tissue hydration increases in M. senile acclimated to dilute seawater, but the increase was not proportional to the change in ambient salinity, indicating that the anemones partially regulate volume in dilute media.4. Mathematical analyses of changes in tissue hydration as a function of ambient salinity in M. senile, Haliplanella lineata, and Diadumene leucolena suggest that the effectiveness of volume regulation increases in individuals of these species acclimated to progressively more dilute media. The volume regulatory capability of Bunodosoma cavernata does not change in dilute media.     

Deletion of Thioredoxin Reductase and Effects of Selenite and Selenate Toxicity in Caenorhabditis elegans

Thioredoxin reductase-1 (TRXR-1) is the sole selenoprotein in C. elegans, and selenite is a substrate for thioredoxin reductase, so TRXR-1 may play a role in metabolism of selenium (Se) to toxic forms. To study the role of TRXR in Se toxicity, we cultured C. elegans with deletions of trxr-1, trxr-2, and both in axenic media with increasing concentrations of inorganic Se. Wild-type C. elegans cultured for 12 days in Se-deficient axenic media grow and reproduce equivalent to Se-supplemented media. Supplementation with 0–2 mM Se as selenite results in inverse, sigmoidal response curves with an LC₅₀ of 0.20 mM Se, due to impaired growth rather than reproduction. Deletion of trxr-1, trxr-2 or both does not modulate growth or Se toxicity in C. elegans grown axenically, and ⁷⁵Se labeling showed that TRXR-1 arises from the trxr-1 gene and not from bacterial genes. Se response curves for selenide (LC₅₀ 0.23 mM Se) were identical to selenite, but selenate was 1/4^th as toxic (LC₅₀ 0.95 mM Se) as selenite and not modulated by TRXR deletion. These nutritional and genetic studies in axenic media show that Se and TRXR are not essential for C. elegans, and that TRXR alone is not essential for metabolism of inorganic Se to toxic species.     

Genetic diversity of Kappaphycus species (Gigartinales,Rhodophyta) in the Philippines

The mariculture of eucheumatoids (species of Kappaphycus and Eucheuma) in the Philippines has had a long history, dating back to the 1970s. Over this period, a number of varieties have been brought into domestication; some are now widely distributed and farmed in various regions of the country, but a significant number appear to have a more restricted distribution and are farmed only in certain areas. The taxonomy of many of these seaweed cultivars and their phylogenetic relationships still remain to be resolved at the specific and subspecific levels. In this study, two mitochondrial DNA markers, COI-5P region and cox2-3 intergenic spacer, were used to assess the genetic diversity of the farmed varieties and a few specimens collected from the wild. Analysis using haplotype networks revealed several new haplotypes for K. alvarezii, K. malesianus and K. striatus, mainly from specimens collected from eastern and southwestern regions of the Philippines. The inferred phylogenetic relationships based on both mtDNA markers resolved the identity of all the materials used in the study at the species level. We present molecular evidence that K. malesianus, in addition to K. alvarezii, K. cottonii, K. inermis, K. procrusteanus and K. striatus (and, hence, all currently recognized species of Kappaphycus) occurs in the Philippines. Collectively, these observations suggest that the Philippine archipelago has richer genetic diversity of farmed and wild Kappaphycus than do the other geographic regions, consistent with the hypothesis that the Philippines is, or is part of, the centre of Kappaphycus biodiversity in the world. These findings also reveal an untapped diversity that can potentially be exploited for improving the commercial production of these carrageenophytes.     

Macroalgal Morphogenesis Induced by Waterborne Compounds and Bacteria in Coastal Seawater

Axenic gametes of the marine green macroalga Ulva mutabilis Føyn (Ria Formosa, locus typicus) exhibit abnormal development into slow-growing callus-like colonies with aberrant cell walls. Under laboratory conditions, it was previously demonstrated that all defects in growth and thallus development can be completely abolished when axenic gametes are inoculated with a combination of two specific bacterial strains originally identified as Roseobacter sp. strain MS2 and Cytophaga sp. strain MS6. These bacteria release diffusible morphogenetic compounds (= morphogens), which act similar to cytokinin and auxin. To investigate the ecological relevance of the waterborne bacterial morphogens, seawater samples were collected in the Ria Formosa lagoon (Algarve, Southern Portugal) at 20 sampling sites and tidal pools to assess their morphogenetic effects on the axenic gametes of U. mutabilis. Specifically the survey revealed that sterile-filtered seawater samples can completely recover growth and morphogenesis of U. mutabilis under axenic conditions. Morphogenetic activities of free-living and epiphytic bacteria isolated from the locally very abundant Ulva species (i.e., U. rigida) were screened using a multiwell-based testing system. The most represented genera isolated from U. rigida were Alteromonas, Pseudoalteromonas and Sulfitobacter followed by Psychrobacter and Polaribacter. Several naturally occurring bacterial species could emulate MS2 activity (= induction of cell divisions) regardless of taxonomic affiliation, whereas the MS6 activity (= induction of cell differentiation and cell wall formation) was species-specific and is probably a feature of difficult-to-culture bacteria. Interestingly, isolated bacteroidetes such as Algoriphagus sp. and Polaribacter sp. could individually trigger complete Ulva morphogenesis and thus provide a novel mode of action for bacterial-induced algal development. This study also highlights that the accumulation of algal growth factors in a shallow water body separated from the open ocean by barrier islands might have strong implications to, for example, the wide usage of natural coastal seawater in algal (land based) aquacultures of Ulva.     

Description of Medwayella independencia (Siphonaptera,Stivaliidae), a new species of flea from Mindanao Island,the Philippines and their phoretic mites,and miscellaneous flea records from the Malay Archipelago

Medwayella independencia, a new species of flea, is described from the tupaiid host Urogale everetti (Thomas) from Mindanao Island, Philippines. Several other species of fleas are also recorded from the Philippines including a single male of Lentistivalius philippinensis Hastriter and Bush, 2013 (previously known only from two males), the bat fleas Thaumapsylla breviceps orientalis Smit and Thaumapsylla longiforceps Traub, a single unidentified female species of Macrostylophora Ewing collected from the murid Bullimus bagobos Mearns, and a pair of Medwayella robinsoni ssp. from Sundasciurus hoogstraali (Sanborn) from Busuanga Island, Philippines. Representatives of Medwayella Traub, 1972 and Macrostylophora have not previously been recorded from the Philippines. A key to the male sex of Medwayella is provided. Phoretic mites of the genus Psylloglyphus (family Winterschmidtiidae) were present under the abdominal sclerites of several male and female specimens of M. independencia. This is the second report of a phoretic mite on a species of Medwayella Traub. The co-evolutionary implications between phoretic mites and fleas are discussed.     

Bioethanol production from the acid hydrolysate of the carrageenophyte Kappaphycus alvarezii (cottonii)

Seaweed resources can be used as raw materials to produce bioethanol, a renewable biofuel, to overcome fossil fuel depletion and environmental problems. Red seaweeds possess high amount of bioethanol-producible carbohydrates. Among 55 species tested, the carrageenophyte Kappaphycus alvarezii (also known as cottonii) was selected as the best resource for bioethanol production. This species is one of the most abundant and easily cultured red seaweeds. The main components of carrageenan are d-galactose-4-sulfate and 3,6-anhydro-d-galactose-2-sulfate, which are potentially fermentable d-typed carbohydrates. The seaweed powder was hydrolyzed with 0.2?M sulfuric acid and fermented with brewer’s yeast. The ethanol yield from the K. alvarezii hydrolysate was 0.21?g?g^?1-galactose, which corresponded to a 41% theoretical yield. It revealed a relative ethanol production of 66% comparing to that of pure galactose.     

MORPHOGENESIS OF MONOSTROMA OXYSPERMUM (KÜTZ.) DOTY (CHLOROPHYCEAE) IN AXENIC CULTURE,ESPECIALLY IN BIALGAL CULTURE1

The typical morphology of Monostroma oxyspermum (Kütz.) Doty is lost in axenic culture. In synthetic media of the ASP type, it grows as a colony-like mass composed of round cells with numerous rhizoids. Such a mass is a fragile structure which falls apart upon shaking, or slight touch, into small cell-groups and single cells or cells with a long rhizoid. Only temporary saccate or monostromatic fronds appear and reach 1–2 mm in length when grown in enriched seawater media, but disintegrate and become a colony-like mass. The typical morphology is easily restored by adding at specific intervals filtrates of bacterial cultures and supernatant medium from axenic brown and red algal cultures to the basal medium (ASP7), or by reinfecting the Monostroma with an appropriate bacterial flora. Furthermore, the typical morphology in also maintained by bialgal cultures between Monostroma and other axenic strains of various species of seaweeds except the species belonging to the Chlorophyceae. Monostroma thus appears to utilize some substances released by most species of brown and red algae for its typical growth. Active substances released by bacteria, brown and red algae have not yet been identified and purified. However, it is demonstrated that in axenic cultures many species of seaweeds produce active extracellular substances which play an important role in growth and Morphogenesis of other species of seaweeds.     

Leishmania tarentolae: Utility as an in vitro model for screening of antileishmanial agents

Primary screens for antileishmanial compounds use Leishmania species pathogenic to humans that must be handled under biosafety conditions that cannot be adopted or guaranteed everywhere. Leishmania tarentolae, a parasite isolated from the gecko Tarentolae annularis, has not been considered pathogenic to humans. Promastigotes of L. tarentolae have been previously used as a eukaryotic expression system for the production of recombinant proteins and in the amplification of genes involved in resistance to antileishmanial drugs. To validate the use of this Leishmania species in the screening of antileishmanial drugs, the sensitivity of axenic and intracellular amastigotes of L. tarentolae was compared to the sensitivity showed by Leishmania species causative of human leishmaniasis. The ability of L. tarentolae to grow as axenic amastigotes is first described while its ability to infect several mammalian cells has been confirmed. L. tarentolae amastigotes offer a suitable model for the in vitro screening of compounds for antileishmanial activity.     

Antibacterial activity of marine macroalgae against fish pathogenic Vibrio species

In mariculture, diseases of microbial origin can cause significant economic losses worldwide; the evolution of microorganism resistance to antibiotics has resulted in a growing need for new antibacterial compounds that are effective in veterinary medicine and characterized by limited undesirable side effects. Increased attention has recently been turned to seaweeds as a promising source for metabolites with antimicrobial activity. Vibriosis is a common disease, caused by bacteria of the genus Vibrio, that can result in high mortality in aquaculture. The aim of this study was to identify seaweeds with antibacterial activity against some pathogenic Vibrio species, in order to identify a possible alternative to the commonly used antibiotics in aquaculture. Chloroform/methanol lipidic extracts of six seaweed species (Chaetomorpha linum, Cladophora rupestris, Gracilaria dura, Gracilaria gracilis, Gracilariopsis longissima, Ulva prolifera) were tested for their antibacterial activities against six fish pathogenic Vibrio species using the disc diffusion method. Different susceptibilities to lipidic algal extracts were observed. All six of the seaweed extracts tested demonstrated inhibition of Vibrio ordalii. The best was that from Gracilariopsis longissima, showing activity against Vibrio ordalii, Vibrio salmonicida, Vibrio alginolyticus and Vibrio vulnificus. The results confirmed the potential use of seaweed extracts as a source of antibacterial compounds or as a health-promoting feed for aquaculture.     

Biofouling ascidians on aquaculture gear as potential vectors of harmful algal introductions

Biofouling ascidians are ubiquitous in coastal ecosystems and are among the main colonizers of aquaculture gear. Our study tested the hypothesis that the transport, removal, and transfer of fouling ascidian species by aquaculturists provide a mechanism for concentration and distribution of harmful-algal cells to new areas. Wild-caught specimens of common, biofouling ascidian species (Styela clava, Ciona intestinalis, Molgula manhattensis, Botrylloides violaceus, Didemnum vexillum, and Botryllus schlosseri) were exposed individually to cultured strains of co-occurring harmful algae (Prorocentrum minimum, Alexandrium fundyense, Alexandrium monilatum, Karenia brevis, Aureococcus anophagefferens, or Heterosigma akashiwo) at simulated bloom cell densities of each HAB species. After feeding, ascidians were transferred to ultrafiltered seawater. Immediately after exposure, and after 24 and 48 h in ultrafiltered seawater, biodeposits were collected and observed microscopically for the presence of intact, potentially viable cells. Subsamples of biodeposits were transferred into culture tubes with ultrafiltered seawater and monitored for algal growth during 8 weeks. Cells of all HAB species were found to pass intact through the ascidian digestive system, remained viable, and in many cases were capable of re-establishing populations at least 48 h post-ingestion. The results of our study will inform industry and managers of the potential threat and ecological impact of spreading biofouling ascidians, and practices to mitigate adverse impacts. Additionally, these management practices have been formally incorporated into a new cost-share program developed to help shellfish producers prevent the further spread of ascidians and associated HAB species.     

Cultivation and utilisation of red seaweeds in the Western Indian Ocean (WIO) Region

Seaweed farming in the Western Indian Ocean (WIO) Region is carried out in a number of countries, most of them farming Eucheuma denticulatum, Kappaphycus alvarezii and Kappaphycus striatum. These species are farmed mostly in Tanzania with limited production in Madagascar, Mozambique and Kenya; current production (2012) stands at 15,966 t (dry weight) year^?1 of Eucheuma and Kappaphycus, valued at US$ 4.2 million with 95 % of this tonnage coming from Tanzania. Other countries in the region have limited or no seaweed production owing to problems of epiphytes, ice ice and markets. The problem of epiphytes coupled with ice ice that WIO countries are facing causes die-off of Kappaphycus which is the preferred species in foreign markets for its thicker gel, kappa carrageenan (vs. the weaker iota carrageenan from Eucheuma). New efforts are put to curb these problems including moving seaweed farms to deeper waters and cultivation trials of other carrageenophytes as well as agar-producing species, agarophytes. Research work has been initiated to evaluate Gracilaria and Hypnea farming and processing in Tanzania, the Republic of Mauritius and Mayotte. Gracilaria farming is at experimental stages as a biofilter of fishpond effluents and as potential species for the production of agar with growth rates of 1.5–1.9 % day^?1. Hypnea farming is only being initiated in Mauritius and Mayotte at present. Other innovations including value addition by making various seaweed products and encouraging the consumption of seaweed as food at least in Tanzania and Mauritius are increasing further the importance of the seaweed farming and processing industry in the WIO Region.     

Extract powder from the brown alga Ascophyllum nodosum (Linnaeus) Le Jolis (AMPEP): a “vaccine-like” effect on Kappaphycus alvarezii (Doty) Doty ex P.C. Silva

The benefits of using Acadian Marine Plant Extract Powder (AMPEP), obtained from the brown algae Ascophyllum nodosum, for improving growth of the red alga Kappaphycus alvarezii has been demonstrated by authors in the Philippines and Brazil, particularly for increasing daily growth rate and mitigation of epiphytes. However, the processes which occur have not been discussed. This study examined in vitro the relationship between those red algal defense mechanisms and K. alvarezii responses using AMPEP treatments. The administration of the extract reduced the effects of the oxidative burst (production of hydrogen peroxide) which may be extremely aggressive for an individual and its epiphyte. The bleaching of the non-corticated portions of Polysiphonia subtilissima thalli that were cultivated as simulated epiphytes with AMPEP samples confirmed that the reaction was evident in which AMPEP protected K. alvarezii from the hydrogen peroxide effects. It is proposed that the use of the brown seaweed powder AMPEP acts as a potential vaccine, eliciting activation of the red seaweed K. alvarezii natural defenses against pathogens and ameliorating the negative effects of long-term exposure to oxidative bursts.     

Taxonomic Boundaries and Craniometric Variation in the Treeshrews (Scandentia,Tupaiidae) from the Palawan Faunal Region

The taxonomy of treeshrews (Order Scandentia) has long been complicated by ambiguous morphological species boundaries, and the treeshrews of the Palawan faunal region of the Philippines are no exception. Four named forms in the genus Tupaia Raffles, 1821, have been described from four island groups based on subtle qualitative morphological characters, and as many as three distinct species have been recognized. A recent molecular phylogenetic study of relationships among Tupaia species suggests that the two currently-recognized treeshrew species from the Palawan faunal region diverged very recently relative to other sister-species divergences within the genus and may not represent species-level taxonomic entities. Here we review the taxonomic and biogeographic histories of the Tupaia taxa from this region. We also collected craniodental data from 133 skulls of all four named forms, representing five island populations, and conducted univariate and multivariate analyses on these data. Our morphometric results are consistent with molecular results, further suggesting that there is insufficient evidence to recognize T. moellendorffi Matschie, 1898, as a separate species from T. palawanensis Thomas, 1894. Our analyses also revealed a craniodentally divergent population from the island of Balabac, which has never been considered a distinct subspecies (or species) from the population on Palawan. These results have conservation implications for the island populations in our analyses, but additional surveys and molecular evidence will be required to fully assess conservation priorities for the treeshrews of the Palawan faunal region.     

Asymbiotic germination response to photoperiod and nutritional media in six populations of Calopogon tuberosus var. tuberosus (Orchidaceae): evidence for ecotypic differentiation

Background and Aims

Ecotypic differentiation has been explored in numerous plant species, but has been largely ignored in the Orchidaceae. Applying a specific germination protocol for widespread seed sources may be unreliable due to inherent physiological or genetic differences in localized populations. It is crucial to determine whether ecotypic differentiation exists for restoration and conservation programmes. Calopogon tuberosus var. tuberosus, a widespread terrestrial orchid of eastern North America, is a model species to explore ecotypic differences in germination requirements, as this species occupies diverse habitats spanning a wide geographical range.

Methods

Mature seeds were collected from south Florida, north central Florida, three locations in South Carolina, and the upper Michigan peninsula. Effects of three photoperiods (8/16, 12/12, 16/8 h L/D) were examined on asymbiotic in vitro seed germination and seedling development of C. tuberosus. Germination and early development was monitored for 8 weeks, while advanced development was monitored for an additional 8 weeks. In an additional experiment, asymbiotic seed germination and development was monitored for 8 weeks on six culture media (BM-1 terrestrial orchid medium, Knudson C, Malmgrem, half-strength MS, P723, and Vacin and Went). A tetrazolium test for embryo viability was performed.

Key Results

Short days promoted the highest germination among Florida populations, but few differences among photoperiods in other seed sources existed. Different media had little effect on the germination of Michigan and Florida populations, but germination of South Carolina seeds was higher on media with higher calcium and magnesium. Tetrazolium testing confirmed that South Carolina seeds exhibited low viability while viability was higher in Florida seeds. Seed germination and corm formation was rapid in Michigan seeds across all treatments. Michigan seedlings allocated more biomass to corms compared with other seed sources.

Conclusions

Rapid germination and corm formation may be a survival mechanism in response to a compressed growing season in northern populations. Ecotypic differentiation may be occurring based on seed germination and corm formation data.Key words: Asymbiotic germination, corm development, Calopogon tuberosus, ecotypic differentiation, native orchid, orchid seed germination, seedling development     

Evaluating asymbiotic seed culture methods and establishing Disa (Orchidaceae) germinability in vitro: relationships, requirements and first-time reports

Many Disa species (80%) have not been germinated in vitro, fuelling conservation fears. Winter-rainfall species are typically germinable, whilst summer-rainfall species are exclusively intractable in vitro. We aimed to establish the in vitro germination requirements for previously ungerminated Disa species. Conventional asymbiotic seed culture protocols were reviewed and their efficacy in summer-rainfall Disa established. Mature seed was subjected to manipulations of media composition and viscosity, incubation temperature and illumination. Immature cultures were also established across four seed maturity classes. Four first-time germinations (D. cooperi, D. nervosa, D. pulchra and D. woodii) resulted from media with increased water availability. Germination rate (>12 weeks), percentage (<30%) and synchrony were not in accordance with values reported for winter-rainfall species (>80% germination in 8 weeks). Germination of immature seed under control conditions was similar to mature seed germination under modified conditions, but neither percentage approached the calculated germination potential (∼viability). Germination control in Disa is proposed as a trade-off between water availability and the presence of phyto-inhibitors in the environment of the embryo—two features typical of seeds exhibiting water-impermeable dormancy.     

Four new Asian species in the lichen genus Pannaria

Abstract:Three new species which have previously been confused with Pannaria rubiginosa are described. The first, Pannaria complanata sp. nov., from southern India, has a possibly subtropical Afro-Asian distribution, the second, Pannaria emodii sp. nov., may be restricted to the eastern Himalayas from Bhutan to Sichuan (China), and the third, Pannaria ramulosa sp. nov. is known only from Java. The last two species are both related toPannaria asahinae P. M. Jørg. from Japan. A fourth new species from southern Taiwan, the isidiate Pannaria formosana, is closely related to Pannaria ramosa Vain., a little known species from the Philippines.     

Study on the effects of near-future ocean acidification on marine yeasts: a microcosm approach

Marine yeasts play an important role in biodegradation and nutrient cycling and are often associated with marine flora and fauna. They show maximum growth at pH levels lower than present-day seawater pH. Thus, contrary to many other marine organisms, they may actually profit from ocean acidification. Hence, we conducted a microcosm study, incubating natural seawater from the North Sea at present-day pH (8.10) and two near-future pH levels (7.81 and 7.67). Yeasts were isolated from the initial seawater sample and after 2 and 4 weeks of incubation. Isolates were classified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and representative isolates were identified by partial sequencing of the large subunit rRNA gene. From the initial seawater sample, we predominantly isolated a yeast-like filamentous fungus related to Aureobasidium pullulans, Cryptococcus sp., Candida sake, and various cold-adapted yeasts. After incubation, we found more different yeast species at near-future pH levels than at present-day pH. Yeasts reacting to low pH were related to Leucosporidium scottii, Rhodotorula mucilaginosa, Cryptococcus sp., and Debaryomyces hansenii. Our results suggest that these yeasts will benefit from seawater pH reductions and give a first indication that the importance of yeasts will increase in a more acidic ocean.     

A decade of change in the seaweed hydrocolloids industry

Seaweed hydrocolloid markets continue to grow, but instead of the 3?C5% achieved in the 1980s and 1990s, the growth rate has fallen to 1?C3% per year. This growth has been largely driven by emerging markets in China, Eastern Europe, Brazil, etc. Sales of agar, alginates and carrageenans in the US and Europe are holding up reasonably well in spite of the recession. However, price increases to offset costs in 2008 and 2009 have begun to have a dampening effect on sales, especially in markets where substitution or extension with less expensive ingredients is possible. These higher prices have been driven by higher energy, chemicals and seaweed costs. The higher seaweed costs reflect seaweed shortages, particularly for carrageenan-bearing seaweeds. The Philippines and Indonesia are the dominant producers of the farmed Kappaphycus and Eucheuma species upon which the carrageenan industry depends and both countries are experiencing factors limiting seaweed production. Similar tightening of seaweed supplies are beginning to show up in brown seaweeds used for extracting alginates, and in the red seaweeds for extracting agar. The structure of the industry is also undergoing change. Producers in China are getting stronger, and while they have not yet developed the marketing skills to compete effectively in the developed world markets, they have captured much of their home market. China does not produce the red and brown seaweeds needed for higher end food hydrocolloid production. Stocking their factories with raw material has led to the supply problems. Sales growth continues to suffer from few new product development successes in recent years; although some health care applications are showing some promise, i.e., carrageenan gel capsules and alginate micro-beads.     

Unrestricted quality of seeds in European broad-leaved tree species growing at the cold boundary of their distribution

Background and Aims

The low-temperature range limit of tree species may be determined by their ability to produce and disperse viable seeds. Biological processes such as flowering, pollen transfer, pollen tube growth, fertilization, embryogenesis and seed maturation are expected to be affected by cold temperatures. The aim of this study was to assess the quality of seeds of nine broad-leaved tree species close to their elevational limit.

Methods

We studied nine, mostly widely distributed, European broad-leaved tree species in the genera Acer, Fagus, Fraxinus, Ilex, Laburnum, Quercus, Sorbus and Tilia. For each species, seeds were collected from stands close to optimal growth conditions (low elevation) and from marginal stands (highest elevation), replicated in two regions in the Swiss Alps. Measurements included seed weight, seed size, storage tissue quality, seed viability and germination success.

Key Results

All species examined produced a lot of viable seeds at their current high-elevation range limit during a summer ranked ‘normal’ by long-term temperature records. Low- and high-elevation seed sources showed hardly any trait differences. The concentration of non-structural carbohydrates tended to be higher at high elevation. Additionally, in one species, Sorbus aucuparia, all measured traits showed significantly higher seed quality in high-elevation seed sources.

Conclusions

For the broad-leaved tree taxa studied, the results are not in agreement with the hypothesis of reduced quality of seeds in trees at their high-elevation range limits. Under the current climatic conditions, seed quality does not constitute a serious constraint in the reproduction of these broad-leaved tree species at their high-elevation limit.