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We determined the chronic effects of dehydration on the photochemical efficiency of a cultivated brown alga, Undaria pinnatifida (Alariaceae, Laminariales), in young sporophytes as cultivated sporelings. The effective quantum yields of photosystem II (ΔF/Fm′) at 50% humidity decreased markedly after 20 min of emersion and dropped almost zero after 60 min of emersion; the values did not restore even after subsequent 1-day immersion. The decreasing values coincided with a decrease in absolute water content of less than 40%. However, under 99% humidity up to 5-day emersion, the ΔF/Fm′ well remained and the last state exhibited a similar level to the initial value after a 48-h emersion at 20 °C and after 72 h of emersion at 10 °C, suggesting that the thalli were not truly dehydrated under saturated humidity and that photosynthetic activity was maintained for several days even without immersion in seawater. In addition, the subsequent growth of young sporophytes exposed to transportation storage stress featuring (1) immersed in seawater with aeration (ST1), (2) those without aeration (ST2), and (3) wrapped in paper towels moistened with seawater (ST3) revealed that the sporophytes exposed at lower temperature exhibited a higher subsequent growth than those at a higher temperature. The subsequent growth of ST3 was lower than ST1; however, the values of ST3 were higher than those of ST2 more than 12 °C, associating with poor seawater quality without aeration. These results indicated that the maintenance of moisture in the alga at low temperatures might be essential for the transportation of the sporelings.

As the largest genus of Halymeniaceae, Grateloupia has been widely reported. Here, we observed the life history and early development of Grateloupia constricata Li et Ding and investigated the effects of temperature, irradiance, and photoperiod on the discoid crust and sporeling development of G. constricata under laboratory conditions. We observed that the type of carpospore development was “mediate discal type”. The life history included homotypic gametophyte (haploid), carposporophyte (diploid), and tetrasporophyte (diploid), with typical isomorphic alternation of generations. The results of double factorial analysis showed that both single factorial effects and interaction among temperature, photoperiod, and irradiance were obviously significant on the discoid crust and sporeling development. Furthermore, we found that the optimum combination of condition for the early growth and development of G. constricata was temperature 20°C, irradiance 80 μmol photons/(m2·s) and photoperiod 16L:8D. This study provides the theoretical basis and technical support for the conservation of the Grateloupia germplasm, artificial breeding, large-scale cultivation and sustainable development.

Isoetes L. is a nearly cosmopolitan rhizomorphic lycopsid genus fundamental to disentangling plant evolution because of its singular position in the Plantae kingdom. A threatened Amazonian species recently described is I. cangae, inhabiting an oligotrophic upland lake over an iron-rich region facing substantial environmental alterations. In this study, we aim to optimize a reproduction protocol that can assist in the conservation efforts of Isoetes species in tropical areas. We observed an average of 126 megaspores or 318,000 microspores per sporangia in field-collected plants. We obtained an elevated percentage of sporelings (63%) from an in vitro mixed culture of mega- and microspores. In addition, we recovered a large number of sporelings around adult plants after cultivating them over quartzite sand and distilled water. The megaspore nutrient reserve ensured longstanding sporeling growth and development in these environmental conditions. However, the sporeling growth rate increased when they were planted over their original lake sediments or over an organic substrate, with nonsignificant differences between the substrates. An increase in temperature also increased the sporeling growth rate. Together with the very low sporeling mortality, these results suggest that I. cangae is a resilient species able to grow and colonize environments with low trophic characteristics with a range of substrates and temperature regimes. The protocols established in this study could be useful for the ex situ propagation and growth of a large number of sporelings, representing critical steps towards the population rescue and conservation of tropical Isoetes species.

We describe a simple and efficient plastid transformation method for the liverwort, Marchantia polymorpha L. Use of rapidly proliferating cells such as sporelings, which are immature thalli developing from spores, as targets made plastid transformation by particle bombardment efficient. Selection on a sucrose-free medium and linearization of the transformation vector significantly improved the recovery rate of plastid transformants. With the method described here, a few plastid transformants are obtained from a single bombardment of sporelings. Homoplasmic transformants of thalli are obtained immediately after primary selection.

Iso&euml, tes sabatina is an aquatic quillwort endemic to Italy. It is one of the rarest quillworts in Europe, and is critically endangered due to restricted range and to the continuous decline of both population and habitat quality. This study aims to develop an optimized protocol to reproduce and grow I. sabatina sporelings. Mature and immature megaspores were mixed with mature microspores to evaluate the influence of the developmental stage on germination and sporeling development. Two substrates, distilled water and water-agar medium, were tested for germination and sporeling emergence, and three substrates, sand, lake sediment and water-agar, were tested for transplants. A high percentage of megaspore germination (a total of 79.1%) was obtained in both substrates, higher for mature than immature spores. A total of 351 sporelings were produced in distilled water and water-agar cultures, with similar percentages (64.5% and 69.6%, respectively). The development stage of the megaspores affected both germination and sporeling development. Sporeling emergence showed significantly higher percentages in mature megaspores than immature ones (69.6% vs. 11.6%, respectively), with 85% of germinated spores developing sporelings. Only transplants over water-agar medium were successful. This protocol could be useful for the propagation of sporelings as the key step towards the planning of in situ actions to save this Mediterranean quillwort from extinction.

The giant kelp farming industry in China, with an annual production of 1.4 million t (dry weight, DW) in a farming area of 130,564 ha, depends on a safe and constant supply of sporelings each year that are nurtured in ca. 20 commercial hatchery enterprises in Shandong and Fujian provinces in the north and south, respectively. Extension of the kelp growing period in the sea relies on the use of the so-called summer sporeling. Its production is based on using recirculated cold water (5–10 °C) to allow gametogenesis to happen and thereafter the young sporophytes to grow in summer when the ambient seawater temperature (above 20 °C) is too high. This allows sporophytic sporelings to be transferred to open water in early autumn, 2 months earlier than naturally occurring plants in coastal populations. Although historically commercially viable and successful, there have been few reports to describe this hatchery process. In this case study, the entire process of a commercial hatchery manipulation in the 2015 production season at Lvshun, Dalian, northern China, is presented, including pre-treatment of parental plants, control of spore release, and control and adjustment of solar irradiance and temperature at different developmental stages of the plants as well as the nutrient supply regime over the entire course. Analyses of the data and process in this report is expected to shed light on future optimization of the technique as well as providing useful clues for other farmed kelp species in other regions of the world.

The endemic red seaweed Sarcothalia atropurpurea is a potentially valuable source of carrageenan, but no information is available on growing this species as a crop in New Zealand. Tetraspores released from wild-harvested reproductive thalli were settled onto strings and grown initially in tanks under two different day-lengths. Seeded strings were transplanted to open water at 2, 6 and 10 weeks after spore release. Gametophytic biomass was harvested twice by pruning plants approximately six and nine months after spore release. Sporeling length was correlated with day length during tank culture but these differences were not apparent after a period of open-water culture. Spores cultured with medium day-length for 6–10 weeks before transfer to open water grew into harvestable plants that contained similar amounts and types of carrageenan to that from wild material. These results demonstrate for the first time that aquaculture of gametophytic S. atropurpurea from tetraspores is possible.

In bryophytes, establishment can occur by a sexual or asexual process, but the production of spores enables colonization of a wider range of habitats and substrates than can asexual propagules. Successful germination is critical for establishment in a new environment. This paper addresses germination and sporeling development in Frullania ericoides, a leafy liverwort species. Fresh spores were inoculated in vitro in different culture strengths of Knop’s nutrient solution (one-fourth strength, half strength, full strength, one and a half strength and double strength), in order to evaluate the effects of this solution on spore germination and on the development of external protonema. On the first assessment, spore germination was observed at all the concentrations. Germination was endosporic, with cell division and proliferation, resulting in a globular protonema, within the spore wall. Beginning at the fourth week, the development of tightly concave primordial leaves was observed in all but the double-strength medium. Throughout the period of study, the treatments with lower concentrations exhibited external protonema with greater lengths. The double-strength treatment was statistically different from other treatments in at least two parameters. The results of this study demonstrate the potential of in vitro culture techniques for bryophyte spore studies and germplasm preservation.

The liverwort species, Marchantia polymorpha, shows environment-dependent morphological plasticity throughout its life cycle. Thalli, representing the predominant body form throughout most of this bryophyte's life cycle, grow with repeated dichotomous branching at the apex and develop horizontally under sufficient light intensity. Spores, after germination, produce a mass of cells, called sporelings, which then grow into thalli. Both thalli and sporelings, if grown under weak light conditions, form narrow shapes, and their apices grow toward the light source. These phototropic responses are specific to blue light and dependent on the blue-light receptor phototropin. This chapter provides several basic procedures, along with some tips, for designing and performing experiments with M. polymorpha to observe their phototropic responses, as well as methods for observing the localization of the phototropin "Mpphot" with a fluorescent protein tag.

The composition and diversity of phycospheric microbes are critical to the health of algae. Pyropia yezoensis is a popular edible seaweed in Asia and yellow spot disease (YSD) is a serious disease during its conchocelis sporeling culture period. We studied the changes of the bacterial flora in the phycosphere and the surrounding seawater of P. yezoensis conchocelis during a YSD outbreak and treatment. Four types of algal conditions were studied 1) healthy (no previous YSD); 2) YSD; 3) YSD being treated with ClO2 and 4) recovery (14 d after treatment). In the YSD samples, the microbial diversity was significantly decreased. The abundance of bacteria that were reported having algal dissolving and degrading functions (Kangiella, Alteromonas, Kordiimona, Tenacibaculum and Winogradskyella) was significantly increased, and some beneficial bacteria (Ruegeria and Bdellovibrio) had significantly decreased populations (P

Takakia lepidozioides is a rare and potentially relictual species of a genus that diverged early in the evolution history of mosses. Plants of Takakia grow very slowly in the wild and are almost too small (only ∼ 5 mm high) to be genetically manipulated. We collected Takakia plants with mature spore-bearing capsules from the Nyingchi region at about 4,000 meters elevation in the Tibetan Plateau. We analyzed the pH and inorganic elements of the soil below the population to then optimize the composition of the Beneck medium that is generally suitable for moss culture. We explored the effects of several factors on spore germination and gametophyte growth and established the conditions for efficient spore germination and rapid gametophyte propagation. The characterization of spore germination and early gametophyte development revealed that the sporeling of Takakia is thalloid as in Sphagnum and Andreaea. These results provide the foundation to facilitate genetic, physiological and biochemical research with T. lepidozioides and also developmental studies, which may contribute to our understanding of the morphological transformations in the early diversification of mosses.

Gracilariopsis lemaneiformis is an economically important red alga worldwide, and is currently cultured by vegetative propagation. However, information related to the practice of spore culturing in red alga, especially for this species, is limited. Here, we describe a successful pilot study that used tetraspores and carpospores for the industrial cultivation of G. lemaneiformis in Jiaozhou Bay, Qingdao, China. Morphological observation and culture studies of G. lemaneiformis spores were carried out in the laboratory and field. Related spore parameters of daily output, germination rate, survival number, and growth rate were determined. The results showed that the maximum daily output occurred on the 6th day for tetraspores, with a value of 5.71 ± 0.68 × 105 g− 1 fresh weight, and on the 4th day for carpospores, with the value of 1876 ± 153 carpospores per cystocarp. During early culturing, the development and growth of tetraspores and carpospores were very similar. Inoculation density variation had significant effects on germination rate, survival number, and growth rate, the highest values of which were recorded at medium density, high density, and medium density inoculation, respectively. After 3 weeks in the field, the tetrasporelings and carposporelings were ~ 3 cm in length. Different heights below sea level also had a notable effect on sporeling growth, and the optimal condition was 0.5 m below sea level. After further culturing, the sporelings showed fast adaptation to the sea with average growth rates of 6.21 ± 0.48% day− 1 for tetrasporophytes and 4.21 ± 0.36% day− 1 for gametophytes. This study has demonstrated that the mass cultivation of G. lemaneiformis using tetraspores and carpospores under controlled culture conditions is feasible, and has also provided valuable information for improving the only available culture method (vegetative propagation) for G. lemaneiformis in the field.

] Muller, J. 2014. Moosflora des Parks Sanssouci in Potsdam. Verhandlungen des Botanischen Vereins von Berlin und Brandenburg 147: 157–184. Muster, C., G. Gaudig, M. Krebs & H. Joosten. 2015. Sphagnum farming: the promised land for peat bog species? Biodiversity and Conservation 24(8): 1989–2009. Na, Y., S. R. Manchester, C. Sun & S. Zhang. 2015. The Middle Jurassic palynology of the Daohugou area, Inner Mongolia, China, and its implications for palaeobiology and palaeogeography. Palynology 39(2): 270–287. Nelson, G., P. W. Sweeney, L. E. Wallace, R. K. Rabeler, D. Allard, H. Brown, J. R. Carter, M. W. Denslow, E. R. Ellwood, C. C. Germain-Aubrey, E. Gilbert, E. Gillespie, L. R. Goertzen, B. S. Legler, D. B. Marchant, T. D. Marsico, A. B. Morris, Z. E. Murrell, M. Nazaire, C. Neefus, S. Oberreiter, D. Paul, B. R. Ruhfel, T. Sasek, J. Shaw, P. S. Soltis, K. Watson, A. Weeks & A. R. Mast. 2015. Digitization workflows for flat sheets and packets of plants, algae, and fungi. Applications in Plant Sciences 3(9): 1500065 [1–9]. Nelson, J. M. 2015. [Abstract] Interactions of the liverwort Marchantia polymorpha with its fungal endophytes. Page 72. In: Botany 2015: Science and Plants for People. Abstracts. July 25–29, 2015, Edmonton Alberta Canada. Nemeth, Cs. 2008. Contributions to the bryophyte flora of SuriBakonyalja, Bakony and Vertes Mts (NW Hungary). Flora Pannonica 6: 79–87. [In Hungarian with English abstract.] Nemeth, Cs. 2009. Data on the distribution of Dicranum tauricum Sapjegin in Hungary. Flora Pannonica 7: 51–55. [In Hungarian with English abstract.] Nilsson, S. 2015. Rapport fran Projekt Skanes mossor varen 2015. Myrinia 25(1): 56–60. [In Swedish with English summary.] Nishihama, R., K. Ishizaki, M. Hosaka, Y. Matsuda, A. Kubota & T. Kohchi. 2015. Phytochrome-mediated regulation of cell division and growth during regeneration and sporeling development in the liverwort Marchantia polymorpha. Journal of Plant Research 128(3): 407–421. Norden, B., A. Gardiennet, J.-P. Priou & P. Dobbeler. 2015. Bryocentria hypothallina (Hypocreales) — a new species on Metzgeria furcata. Ascomycete.org 7(4): 121–124. Novotný, I. & R. Mudrova. 2015. Ecology and distribution of the rare copper moss Streptocolea atrata (Bryopsida, Grimmiaceae) in the Czech Republic. Acta Musei Silesiae, Scientiae Naturales 64(1): 23–26. Nydahl, A. C., C. K. King, J. Wasley, D. F. Jolley & S. A. Robinson. 2015. Toxicity of fuel-contaminated soil to Antarctic moss and terrestrial algae. Environmental Toxicology and Chemistry 34(9): 2004–2012. Buck & Atwood: Recent literature on bryophytes 101

Sporeling and tissue propagation of agarophytic seaweed, Gracilaria fisheri, aimed to investigate the optimal shading colour for the preservation. This study was conducted under different shading colours indoor and outdoor experiments. The indoor experiment: tissues and sporelings of the seaweed were cultured in plastic chambers under fluorescent lights and were wrapped with white, green, blue and red colour PVC sheets of light intensity of 20 ± 1 μmol m−2 s−1. The outdoor tissues were cultured in the plastic tanks under different shadings of Saran sheets: white, green, blue and black covering the hoop-houses with light intensity of 110 ± 10 μmol m−2 s−1. The results showed that different shading colours strongly influenced growth of G. fisheri sporelings and tissues but little effect on pigmentation. After 40 days, the highest growth rates of G. fisheri tissues and sporelings were found under red light with 1.44 and 1.89% day−1 respectively. There was no significant difference (P > 0.05) on pigment content of tissues indoor, whereas it was found that chlorophyll concentration of the sporelings under green light with 416.8 μg g−1 fresh weight was significantly higher (P

Pyropia is an important cultivated seaweed in Northeast Asia. Yellow spot disease (YSD) commonly occurs in conchocelis sporeling cultures of Pyropia and causes huge economic losses. In this study, the isolated strain 117-T6 was identified as a pathogenic bacterium of YSD in Pyropia by Koch's postulates. Based on the morphological, physiological, and biochemical characteristics and multi-locus analysis of house-keeping gene sequences, this gram-negative bacterium was named as Vibrio mediterranei 117-T6. V. mediterranei 117-T6, including its intracellular and the extracellular extracts, caused both free-living conchocelis (FLC) and shell-borne conchocelis (SBC) to exhibit YSD symptoms within 12 days, indicating that the bacteria might attack Pyropia by secreting certain compounds that can be transported into algal cells, breaking down their structure and leading to death. During the infection, four stages were observed. 1) Prophase: a large number of pathogenic bacteria gathered around the algae. The conchocelis was in healthy condition at that time. 2) Early stage: organelle edges of Pyropia were blurred, mitochondria and chloroplasts became fluffy and unraveled, autophagosomes appeared. 3) Middle stage: cellular structures and contents of the algae kept being lost and degraded, cell walls became thin. 4) Late stage: the conchocelis bleached completely, and as the cell wall disintegrated gradually, the bacteria took over the remains of Pyropia. Finally, the whole algal cell disappeared, which may be the reason for shell bleaching. Our results show that YSD caused by V. mediterranei 117-T6 is a severe disease of algal disintegration caused by bacterial secretion, with a short onset and severe symptoms.

Undaria pinnatifida is an annual brown kelp growing naturally in coastal areas as a major primary producer in temperate regions and is cultivated on an industrial scale. Kelps have a heteromorphic life cycle characterized by a macroscopic sporophyte and microscopic sexual gametophytes. The sex-dependent effects of different environmental factors on the growth and maturation characteristics of the gametophyte stage were investigated using response surface methodology. Gametophytes were taken from three sites in Japan: Iwate Prefecture, Tokushima Prefecture, and Kagoshima Prefecture in order to confirm the sexual differences in three independent lines. Optimum temperature and light intensity were higher for males (20.7&ndash, 20.9 &deg, C and 28.6&ndash, 33.7 &micro, mol m&minus, 2 s&minus, 1, respectively) than females (16.5&ndash, 19.8 &deg, C and 26.9&ndash, 32.5 &micro, 1), and maturity progressed more quickly in males than females. Optimum wavelengths of light for growth and maturation of the gametophytes were observed for both blue (400&ndash, 500 nm, &lambda, max 453 nm) and green (500&ndash, 600 nm, &lambda, max 525 nm) lights and were sex-independent. These characteristics were consistent among the three regional lines. Slower growth optima and progress of maturation could be important for female gametophytes to restrict fertilization and sporophyte germination to the lower water temperatures of autumn and winter, and suggest that the female gametophyte may be more sensitive to temperature than the male. The sexual differences in sensitivity to environmental factors improved the synchronicity of sporeling production.

The aquatic quillwort Isoetes lacustris L. survived five decades of severe acidification in Cerne Lake (Bohemian Forest, central Europe), but failed to reproduce. To detect which ontogenetic stage is more affected by water acidification and to identify water chemistry thresholds for successful recruitment, experiments were carried out on quillwort sporelings grown in the laboratory, using different pH (4–8) and aluminium (Al) concentrations (0–1000 μg/L). Growth-related symptoms and Al accumulations in tissues were compared with those observed in sporelings collected in the lake. In the laboratory, the threshold Al concentrations ≥100 μg/L and pH ≤ 5.0 reduced absorptive organs (macrogametophyte rhizoids, roots, and root hairs), so that the ratio of below-ground to above-ground sporeling biomass decreased to

Chimerism theoretically increases the genetic heterogeneity of coalescing organisms, which in turn may increase phenotypic variability in chimeras, allowing them greater tolerance to environmental changes when compared with non-coalescing individuals. In order to test this hypothesis, we compared abiotic stress tolerance between coalescing and non-coalescing organisms. The specific daily growth was compared using discs formed with 1, 5, and 20 Mazzaella laminarioides carpospores. These were cultivated under three different temperature (6, 12, and 25 °C) and salinity (10, 35, and 50 g L−1) conditions. Growth of the disc area was measured after 30 days of cultivation under controlled conditions. Sporeling survival similarly was calculated under each of these temperatures and salinities in order to record whether stress-resistant phenotypes were present. The results showed that, under stressful conditions, non-coalescing specimens experienced a significant reduction in the specific growth rate compared with those under non-stressful conditions. The reduction in growth falls off, however, as the number of coalescing spores increases. The cultivation of spore populations also indicates the presence of sporelings with the capacity to survive alone in stressful situations. The results suggest that the coalescing discs exhibit higher tolerance to environmental stressors than non-coalescing discs, allowing them to survive and grow under these conditions. This can be explained by an increase in phenotypic plasticity, resulting from greater genetic heterogeneity due to somatic fusion of a larger number of spores.

Notothylas vitalii is an endemic Brazilian hornwort species, easily identifi ed by the absence of pseudoelaters and columella, and the presence of yellow spores. Plant material was collected in Recife, Brazil, and the spores were sown onto Knop’s medium, germinating after thirty days only with the presence of light. Germination occurred outside the exospore, and only after the walls had separated into three or four sections did a globose sporeling initiate its development. Following longitudinal and transversal divisions, the initial loose mass of cells became a thalloid gametophyte, subsequently developing into a rosette-like juvenile thallus with fl attened lobes. Additional information concerning sporeling types in key genera of hornworts, such as and FoliocerosPhymatoceros, will be crucial for inferring the possible ancestral type and the evolution of this trait among hornworts. Our study supports the necessity of supplementary studies on sporeling development, combined with morphological and phylogenetic investigations, to help elucidate the evolution of the Anthocerotophyta and their distribution patterns.

Two experiments were conducted to study Gloiopeltis furcata spore culture with different substrates in the nonreproduction season. Using spores discharged by fertile G. furcata frozen for storage, two experiments were conducted during the nonreproduction season. In the first experiment, G. furcata spores were collected and incubated in aquariums using palm line, polythene line, vinylon line, and three types of plastic sheets (white, ripple, and transparent polymethyl methacrylate) as substrates. In the second experiment, G. furcata spores were collected and incubated in a plastic tank using plastic sheets of different materials (PP, PE, and transparent PVC) and plastic even nets of different mesh sizes (3, 2, and 0.5 cm) as substrates. At the end of the experiment (after 60 d), discs with raised thallus were found on different plastic sheets and white plastic even nets, but no discs were visible on any type of line or on the black plastic even net (3-cm mesh). The white plastic even net was found to be a suitable substrate for G. furcata spore culture in farms and for sporeling culture in sea. Results presented in this study are expected to aid in the progress of the artificial seeding of Gloiopeltis.

Silvetia babingtonii is a potentially economic brown alga for sources of food and high-value added utilization. So far, sporeling nursery and field cultivation has not been successful. The lack of knowledge on development and life cycle of this alga hinder the development of techniques for the sporeings and cultivation. In this study, internal structure of oogonium and antherium of S. babingtonii was observed with hematoxylin and eosin staining and through microscope. Meanwhile, early development from zygotes to juvenile sporelings was studied at 20 degrees C under 60-100 mu mol photons m(-2) s(-1). Zygotes germinated and divided into thallus and rhizoid cells. The larger thallus cells further divided and developed into juvenile sporelings; while the smaller rhizoid cells divided and elongated into rhizoid hairs. These findings documented the life cycle of S. babingtonii and provided fundamental knowledge for sporeling nursery in the near future.

A colony of a fern, Lygodium hians E.Fournier (Schizaeales), studied on the southwest Pacific Island of New Caledonia, displays a growth form unusual for any member of this genus. Other living species of the genus Lygodium Sw. are characterized by twining fronds, with indefinite growth, which climb extensively on the support provided by other nearby vegetation. These fronds can arise from as early as the sporeling stage and fulfil both vegetative and reproductive functions, with spores produced in lateral sorophores in the upper parts of the fronds. By contrast, in L. hians, climbing fronds are only rarely produced and these carry terminal to subterminal sorophores. The main vegetative growth is of a low-growing (here termed ‘ground-clothing') frond-type, of definite, rather than indefinite, growth and of unusual dichotomous blade structure. This life form has survived, in this rare and little known remote species, under conditions of considerable ecological, as well as geographic, isolation in t...

Sargassum thunbergii is an economically important brown alga that is used as a perferred food for sea cucumber in China. However, reports on the reproductive biology of S. thunbergii are limited. This study observed the characteristics of mature receptacles. The effects of different temperatures, light intensities, and photoperiods on the egg release of mature S. thunbergii receptacles were investigated. A liquid-phase oxygen electrode system was used to obtain light saturation and light compensation points of egg and young thalli of S. thunbergii. Results showed that temperature was the key factor for the egg release of mature receptacles. The conditions most conducive to egg release were 20&degC to 23&degC temperature and 50 μmol photons m-2&middots-1 to 200 μmol photons m-2&middots-1 light intensity. In addition, the light saturation and compensation points of unfertilized eggs or young thalli at 2 d or 3 d postfertilization ranged from 90 μmol photons m-2&middots-1 to 120 μmol photons m-2&middots-1 and 14 μmol photons m-2&middots-1 to 22 μmol photons m-2&middots-1, respectively. The combined results provide a reference for the sporeling culture of S. thunbergii.

The effects of temperature on spore release, growth and photosynthetic efficiency of Lithophyllum yessoense and Hildenbrandia rubra were examined. L. yessoense was collected at Galnam and H. rubra was collected at Gyeokpo, Korea. The experimental temperatures were different for spore release (10, 15, ), sporeling growth (10, 15, 20, 25, ) and photosynthetic efficiency (10, 15, 20, ). All other culture conditions were the same: 34 psu, 12:12 LD and photon . Spore liberation was maximal at for L. yessoense and at for H. rubra. After 14 days, the surface area of L. yessoense was 0.031 at and for H. rubra was 0.032 at . Sporelings of L. yessoense were a dark-red color and grew in a round shape. In contrast, H. rubra was bright pink and changed from a round shape in the early growth stage to later become flabelliform. Photosynthetic efficiency was highest between in both species. In conclusion, L. yessoense and H. rubra display different physiological features based on the optimal temperatures for spore release and sporling growth.

Gracilariopsis lemaneiformis is an important economic macroalgae worldwide. At present it is mainly cultured by vegetative propagation, which is labor intensive, bulky, and requires large amounts of propagating material. To identify the optimal conditions for spore release, spore development, and fertilization success of Gp. lemaneiformis, four levels of each of four factors (light, temperature, salinity, and photoperiod) were tested using an orthogonal experimental design. Variations in temperature and salinity had significant effects on carpospore yield, and the optimal conditions for carpospore release were 20 °C, 35‰, 15 μmol m− 2 s− 1, and 8/16–14/10 h L/D. The main factors that influenced tetraspore release were temperature, light, and salinity, with the optimal combination being 25 °C, 15 μmol m− 2 s− 1, 35‰, and 8/16–14/10 h L/D. Temperature variation also had an effect on spore development, whereas the effects of the other factors were not significant. The optimal conditions for tetraspore development were 25 °C, 45 μmol m− 2 s− 1, 12/12 h L/D, and 25‰, and for carpospore development they were 25 °C, 45 μmol m− 2 s− 1, 30‰, and 12/12 h L/D. Temperature significantly affected fertilization success of male and female gametophytes, whereas salinity, photoperiod, and light intensity had no significant effect (P > 0.05). The optimal combination of factors for fertilization success was 25 °C, 30‰, 12/12 h L/D, and 15–45 μmol m− 2 s− 1. The culture time of sporeling growth was reduced by about 3–4 months in the study, the results of which can also provide valuable information for genetic breeding, large-scale culture of spores, and algal cultivation.

Grateloupia turuturu Yamada is an economically valuable red alga with great potential in nutraceuticals and pharmaceuticals. Filaments of G. turuturu are of primary importance in germplasm preservation and sporeling culture, although filaments were not present in its life cycle. In this study, effects of temperature (10, 15, 20, 25, and 30 °C) and irradiance (10, 30, 60, and 90 μmol photons m−2 s−1) with photoperiod 10:14 h (light/dark) on filament development were investigated. Our results indicated that 25 °C was the optimal temperature for the formation of discoid crusts regardless of the irradiance. Conditions of 20 °C and 60 μmol photons m−2 s−1 promoted the development of discoid crusts and formation of upright thalli.

The diversity of epiphytes, their temporal abundance variation and the anatomical structure of host–epiphyte interfaces were studied in the agarophyte Gracilaria gracilis from a natural bed in Bahia Bustamante, Chubut Province, Argentina. Twenty-nine algal species were recorded as epiphytes during 2 years of monthly sampling (March 2006–February 2008). Total epiphyte density ranged between 0.037 ind. cm−2 (November 2006) and 39.37 ind. cm−2 (April 2007), with higher density values throughout the second sampling year. Ceramiales species were the most abundant epiphytes. The density of Ceramium rubrum ranged from 0.09 ind. cm−2 (52 % of the total amount) in September 2006 to 17.4 ind. cm−2 (44.18 % of the total amount) in April 2007. Epiphyte infection was more dependent on spore recruitment and sporeling development, especially on thalli derived from fragmentation, than on seasonal environmental variations. The different infections were analysed, taking into account the epiphytic attachment strength and invasiveness and the degree of damage inflicted on the host. Calothrix confervicola was one of the most abundant species. This epiphyte, weakly attached to the host surface, generated no host tissue damage. In contrast, C. rubrum, Polysiphonia abscissa and other Ceramiales were the species that caused more damage to the host because their rhizoids penetrated the cortical portion of the host thallus, sometimes reaching the medullary tissue. Some generalisations and characterisations of the different epiphyte groups in relation to their consequences to Gracilaria spp. are presented.

Dolichomitriopsis diversiformis is an endemic and threatened moss in eastern Asia. In vitro culture and light microscopic observation were employed to study its developmental process from spore germination to the formation of young gametophyte, as well as effects of light and temperature on its spore germination and protonemal development. Microscopic observations revealed that its spores were positively photoblastic with exosporous germination, and sporelings were classified as the bryum-type. Light and dark conditions were compared to understand their effects on spore germination. In 24 h continuous illumination, all spores germinated in both 20 ℃ and 25 ℃. In contrast, in darkness at 20 ℃ from one to 30 days, spores did not germinate. However, when dark-cultured spores transferred to continuous light, they started to geminate in 48 hours. In addition, effects of 20 ℃ and 25 ℃ on sporeling were compared. In a continuous light condition, sporelings grew longer and developed more protonema branches in the 20 ℃ treatment than in the 25 ℃ treatment. It was interesting that a phenomenon of slow and hysteretic spore germination and protonematal development was observed in natural light and room temperature (5-10℃). These observations suggest that spore germination and sporeling development is regulated by light and temperature.

The success of seaweed cultivation depends on the scientific control of the tolerance limits and the optimal physiological conditions that affect the spore germination and the early development of algal species. In order to establish cultivation techniques for spores of Hidropuntia caudata (J. Agardh) Gurgel & Fredericq, the effects of irradiance, salinity, and temperature on the carpospore germination and carposporeling development were evaluated under laboratory conditions. Five photon flux densities (PFD, from 18 to 200 µmol photons m-2s-1), six salinity values (from 7 to 55 psu), and four temperatures (from 20 ºC to 35 ºC) were investigated. The level of irradiance caused significant differences in the growth, in the following order: 200±5 > 100±5 62.5±2.5 > 30±1.5 > 18±1 µmol of photons m-2s-1, but they did not inhibit the carposporeling development. Maximum growth occurred under 35 psu, while at 15 psu the formation of carposporeling erect axis was limited. The optimal temperature for growth was 25 ºC, while at 35 ºC the spores died. These results show the importance of previous knowledge on the tolerance limits and optimal conditions for sporeling development of H. caudata for the implementation of an aquaculture program.

Cultivation of Palmaria palmata was performed by a technique introduced in this paper of tetraspore release and attachment to culture string. Optimal conditions for laboratory growth were investigated with respect to irradiance and nutrient media. The length of laboratory culture required for the growth and development of attached sporelings was also investigated, prior to deployment of seeded strings on a longline structure in Strangford Lough, Northern Ireland. Of sporelings grown in 5, 10, 25 and 50 μmol m − 2 s − 1 , those at the lower irradiances (5 and 10 μmol m − 2 s − 1 ) were significantly longer than those at higher irradiances after 12 weeks. Sporeling length was also significantly greater at lower irradiances when in F/2 nutrient media with additional vitamin solution, compared with F/2 medium without the vitamin solution. Seeded string was held in the laboratory for 2, 4, 6, or 8 weeks. After 3 months at sea, the 2-week strings had fewer visible plants and had shorter plants than the 4, 6 and 8-week strings, but plants on all strings were similar in length after 7 months at sea. The demand for P. palmata as a snack food in Northern Ireland regularly outstrips the supply obtainable from natural populations. The technique of seeding string with tetraspores is proposed as one method of commercially cultivating P. palmata on a large scale.

The phenology of Campylaephora hypnaeoides J. Agardh and optimal conditions for carpospore release, growth and reproduction were examined in the field and in the laboratory from January to December 2007. In the field population of C. hypnaeoides, approximately 50% of the plants were vegetative during the study period. Additionally, the percentages of carposporophytes and tetrasporophytes were maximal in April (37%) and June (57%), respectively. Maximum growth in plant length, dry weight, and hook number coincided with the tetrasporophyte reproductive peak in the field. In culture, carpospore release, sporeling growth and reproduction were affected by environmental factors such as daylength, temperature, and salinity. The liberation of carpospores was maximum under continuous light and at a combination of and photons . Maximum growth of tetrasporophyte sporelings occurred at a combination of photons of constant light and . However, the growth of gametophyte sporelings was maximal under photons of constant light and in a combination of and 35 psu. The tetrasporophyte sporelings were grew faster than gametophytes, indicating that gametophyte- and tetrasporophyte-sporelings have different physiological responses to irradiance and temperature. Tetrasporangial branches and cystocarps of C. hypnaeoides were produced from carpospores and tetraspores within 1 month, and they were stimulated at high temperature and irradiance levels. In conclusion, C. hypnaeoides should be seeded using carpospores during early winter (November-December) because cystocarps are easily identified by fishermen, and tetrasporophytes grow faster than gametophytes.

Spore germination characteristics of Azolla filiculoides Lamarck, a recent invader of the Donana Mediterranean wetlands, have been quantified experimentally. Batches of spores were subjected to different storage conditions, salinity concentrations, phosphorus availability and drought effects. Cold pre-treatment did not stimulate spore germination, whereas drought, a characteristic different from Azolla 's native habitat, reduced it (40 ± 7 vs 13 ± 5). Germination declined with the increase of salinity (r = −0.50, notably above 5000 μS cm −1 ), whereas phosphorus availability had no significant effect.

Saccharina japonica is a brown alga that has been commercially cultured on a large scale in China. Integrating the light condition under seawater and the adaptation of Saccharina to this condition, it is expected that blue light would be beneficial to Saccharina culture system. Consequently, the detailed effect of blue light on the key stages during indoor seedling culture of S. japonica was investigated in this study. Irradiances and light qualities had little effect on zoospore attachment and germination. Egg formation occurred sooner under blue light than white light. Under optimum irradiances, 95 ± 4% female gametophytes gave rise to eggs in 6 d under blue light, while it took 12 d for over 90% formation of eggs under white light. Over a culture period of 3 weeks, mean sporeling length and width under blue light was 1.39 and 1.56 times of that under white light, respectively, while the mean sporeling size obtained under red light was only 25% of that under white light. The higher growth rate under blue light was largely due to higher photosynthetic efficiency, as indicated by chlorophyll fluorescence of photosystem II. In addition, the mean ratio of sporeling width to length under blue light was significantly higher than that under white light. These results suggest that blue light would be superior to white light for indoor seedling culture of S. japonica. Based on these findings, an improved S. japonica seedling culture system is discussed.

Sporeling development in Cavicularia densa was determined using controlled culture and light microscopy techniques. Ontogeny is typified by endosporic germination followed by early protonematal development via the production of a terminal quadrant of four cells which ruptures the spore wall distally. Sporeling production is triggered by the delimitation of a cuneate apical cell in one of the quadrants. Regular apical cell segmentation produces derivatives and adult merophytes that ultimately result in a juvenile Cavicularia gametophyte. The fundamental sporeling pattern exhibited by Cavicularia is shared only with that of its sister genus Blasia. Moreover, the patterns of sporeling and gemma/gemmaling ontogeny in Cavicularia and Blasia share quadrant systems of precise uniformity, thus reinforcing the close relationship between the blasialean genera.

Light regulates various aspects of development throughout the life cycle of sessile land plants. Photoreceptors, such as the red (R) and far-red (FR) light receptors phytochromes, play pivotal roles in modulating developmental programs. Reflecting high developmental plasticity, plants can regenerate tissues, organs, and whole bodies from varieties of cells. Among land plants, bryophytes exhibit extraordinary competency of regeneration under hormone-free conditions. As an environmental factor, light plays critical roles in regeneration of bryophytes. However, how light regulates regeneration remains unknown. Here we show that using the liverwort Marchantia polymorpha, which contains a single phytochrome gene, the phytochrome regulates re-entry into the cell cycle and cell shape in newly regenerating tissues. Our morphological and cytological observations revealed that S-phase entry of G1-arrested epidermal cells around the midrib on the ventral surface of thallus explants was greatly retarded in the dark or under phytochrome-inactive R/FR cycle irradiation conditions, where, nevertheless, small, laterally narrow regenerants were eventually formed. Thus, consistent with earlier descriptions published over a century ago, light is not essential for, but exerts profound effects on regeneration in M. polymorpha. Ventral cells in regenerants grown under R/FR cycle conditions were longer and narrower than those under R cycle. Expression of a constitutively active mutant of M. polymorpha phytochrome allowed regeneration of well grown, widely expanded thalli even in the dark when sugar was supplied, further demonstrating that the phytochrome signal promotes cell proliferation, which is rate-limited by sucrose availability. Similar effects of R and FR irradiation on cell division and elongation were observed in sporelings as well. Thus, besides activation of photosynthesis, major roles of R in regeneration of M. polymorpha are to facilitate proliferation of rounder cells through the phytochrome by mechanisms that are likely to operate in the sporeling.

Study on the early development of sporelings from carpospores ofGracilaria asiatica Chang et Xia was conducted indoors under controlled culture conditions. Besides normal development of sporelings, a new developmental phenomenon of filamentous frond was observed. It was composed of one or two rows of cells, and took place from the outmost brim of the basal disc. During the early disc stage of germinated carpospores, one or two filamentous fronds formed on about 10% basal discs. Simultaneously, young fronds began to arch slightly from the centers of single and coalescent discs; lately more filamentous fronds up to 80% appeared on the brims of basal discs. Meanwhile one or more upright fronds protuberated on the basal discs. Generally, filamentous fronds exhibited in self-existence or co-existence forms with normal young sporelings on the same basal disc, and single cell detached from filamentous fronds developed into a new filamentous frond. This new phenomenon exhibited a unique differentiation pathway during the early development ofG. asiatica, which would be potential for the application in artificial sporelings nursery.

Several phycocolloid-producing Rhodophyta of significant economic importance are coalescing species, able to fuse with conspecifics during recruitment, reach larger sizes and increase their survival. In these species spores are needed to start cultivation (e.g. Gigartina, Mazzaella) or to increase the seed stocks, to renew senescent clones or to enlarge the base of genetic variation of vegetatively propagated species (e.g. Chondrus, Gracilaria, Eucheuma). This study uses Mazzaella laminarioides to evaluate some key features that influence recruitment success. Field measurements indicate that in any recruitment event a variable amount of the spores reaching a given place may form groups of 2 to over 100 coalescing spores, while field experiments support the idea that early recruitment success is a function of the number of coalescing spores forming the individual, as multisporic, coalescing recruits have higher survival rates than sporelings formed by one or a few spores. Therefore, group recruitment (spores settling and recruiting in close spatial proximity) appears as a prerequisite for sporeling coalescence and early recruitment success. In turn, laboratory experiments suggest that the frequency of group recruitment and coalescence increases with increasing spore abundance and with slight Ca++ additions to the culture medium. These last two factors could be handled by farmers to improve the success of spore inoculations of coalescing species.

The pattern of gemma/gemmaling ontogeny in the liverwort Blasia pusilla L. is described from its origin as a primordium within the gemma receptacle to the formation of a juvenile gametophyte. Data were obtained from herbarium specimens, field-grown and axenically cultured plants, using a combination of light and scanning electron microscopy techniques. A consistent, uniform, fundamental developmental pattern was elucidated that is characterized by the production, within the receptacle, of a discoid to ellipsoid, stalked gemma composed of distinct tiers of thick-walled cells and margined by lateral columns of thin-walled, potentially active cells. After dispersal from the receptacle, lateral growth ensues from a gemmaling initial that is produced via quadrant formation from one lateral margin cell. Ultimately, an adult cuneate apical cell is honed that generates segments the same as in the adult plant to produce the juvenile gametophyte typical of Blasia. Both the gemmaling and sporeling ontogenie...

The fine structure of released, attached, and germinating carpospores of Porphyra variegata (Kjellm.) Hus is described. Adhesive vesicles, formed during sporogenesis and discharged upon settling of the spore, produced a layer of adhesive mucilage around the spore and filled a deep imagination on the spore's ventral side. The mucilage layer was punctured by the emergence of a germ tube. Both spore and germ tube were lined by newly deposited cell wall. Germination was accompanied by vacuolation and starch mobilization. The morphological development of the sporeling was not noticeably influenced by the great variability of the timing, location, and orientation of septum formation. The attached carpospore possessed a plastid like that of gametophyte cells: stellate with one large central pyrenoid and no peripheral encircling thylakoids. Cells of mature vegetative cells of the conchocelis had plastids that were elongate and parietal and had multiple pyrenoids and encircling thylakoids. Most stages in the transition between the two forms of plastids occurred during carpospore germination.

Year-round induction of sporogenesis of Laminaria saccharina was performed by mechanically blocking the transport of the putative sporulation inhibitors produced by the blade meristem and culturing the plants in constant short days. Sporogenesis was successfully induced by removal of the blade meristem, either by cultivating distal blade fragments or by performing a transverse cut in the frond. The earliest sorus formation after artificial induction was 10 days. The age of the sporophytes used for induction was 6-11 months or 2 years in tank-grown or field-collected sporophytes, respectively. Zoospores were successfully released in all cases. Thus, by year-round artificial induction of sporogenesis, (1) sporeling production of L. saccharina and thereafter sporophyte cultivation could be achieved without seasonal limitation, and (2) the life cycle of L. saccharina (from spore to spore) could be completed within 8 months under controlled conditions. (C) 2004 Elsevier B.V. All rights reserved.