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1.
Effect of temperature and irradiance on growth and reproduction of Enteromorpha prolifera that bloomed offshore along the Qingdao coast in summer 2008, was studied. It was showed that E. prolifera propagated mainly asexually with specific growth rate （SGR） of 10.47 at 25℃/40 μmol m^-2s^-1. Under this condition, gametes with two flagellate formed and released in 5 days. At the beginning of the development, the unicell gamete divided into two cells with heteropolarity, and then the apical cell developed into thalli primordial cells, whereas the basal cell developed into rhizoid primordial cells. In 8-day culture, the monoplast gamete developed into juvenile germling of 240 μm in length. Unreleased gametes can develop directly within the alga body. E. prolifera could either reproduce through lateral branching or fragmenting except apomixis revealed by Microscopic observation. On aged tissue of E. prolifera, although the degraded pigments partially remained in faded algal filaments, numerous vegetative cells could still divide actively in the algal tissues. 相似文献
2.
Costaria costata (C. Agardh) Saunders is one of common kelps distributed in many coastal areas worldwide; however, in China, no reports have
been made on cultivation of the genus. To investigate potential cultivation of the species in the northern part of China,
trials on isolation and preservation of the gametophytes were conducted using C. costata from Korea; growth and development of the gametophytes were observed. We showed that at 10±1°C, 60 μmol m−2s−1 and 12:12 h (L:D), freshly released zoospores settled down within 1 hour, and then developed into the primary cell during
the following 2 days. After a vegetative growth phase lasting 6–8 days, female gametophytes became 3–4 times larger in diameter
than that of the primary cell, but still remained at a unicellular stage, while male gametophytes divided into 4–10 cells
with only a slight change in size. Fertilization occurred within 10 days after the zoospores were released from the sporangia,
and the apical and basal tissues of the juvenile sporophyte divided and differentiated into the blade and stipe. Temperature
and irradiance influenced gametophytic vegetative growth and developmental patterns. Generally, low irradiance (15 μmol m−2s−1 and 30 μmol m−2s−1) was unfavorable to the induction of fertility, but it enhanced female gametophyte division. The optimal conditions for vegetative
growth were 15°C and 30 μmol m−2s−1. After transplantation of the juvenile seedlings and after eight months cultivation, the harvested mature blade reached 194
cm in length and 32.7 cm in width. Our study proves that it is feasible to implement propagation and large scale cultivation
of C. costata in northern China. 相似文献
3.
Acrochaete leptochaete,a species in Chaetophoraceae(Chlorophyta),was observed during our recent laboratory culture of the macroalgae Chaetomorpha that was originally collected from an intertidal pool in Rongcheng,Shandong Province,China.This is the first record of this species in China.Its morphology,taxonomy,and distribution were introduced and discussed in detail.Isolated culture experiments at different temperatures(9-29℃)and light intensities(36-108μmmol/m 2·s)were also carried out.The culture-based observations have extended our knowledge of growth morphology and general biology of the species. 相似文献
4.
The light demands of seaweeds is an interesting and rather complex phenomenon because they depend not only on the species
but also on their different development stages. Even different parts of the same plant sometimes have different light demands.
Light control is an important procedure at large scaleLaminaria nursery stations in China. Technicians and scientists have different viewpoints on the best method to regulate light. A culture
study onLaminaria japonica starting from zoospores to several centimeter sporophytes to find the optimal and critical irradiance ranges for juvenileLaminaria at different development stages added more knowledge on this aspect. Experiment results show gametophytes can not tolerate
irradiance of more than 150 μE m−2s−1 while sporophytes can tolerate more than 519 μE m−2s−1. This big difference starts from the very early stage of 1-to 2-celled sporophytes. The biological basis and mechanism of
this phenomenon need further research.
Contribution No. 1515 from the Institute of Oceanology, Academia Sinica
Contribution No. 1 from the Experimental Marine Biological Laboratory 相似文献
5.
Most studies on Haematococcus pluvialis have been focused on cell growth and astaxanthin accumulation;far less attention has been paid to cell cycles and proliferation patterns.The purpose of this study was to clarify cell cycles and proliferation patterns in H.pluvialis microscopically using a camera and video recorder system.The complicated life history of H.pluvial i s can be divided into two stages:the motile stage and the non-motile stage.All the cells can be classifi ed into forms as follows:motile cell,nonmotile cell,zoospore and aplanospore.The main cell proliferation,both in the motile phase and non-motile phase in H.pluvialis,is by asexual reproduction.Under normal growth conditions,a motile cell usually produces two,sometimes four,and exceptionally eight zoospores.Under unfavorable conditions,the motile cell loses its fl agella and transforms into a non-motile cell,and the non-motile cell usually produces 2,4 or 8 aplanospores,and occasionally 20–32 aplanospores,which further develop into non-motile cells.Under suitable conditions,the non-motile cell is also able to release zoospores.The larger non-motile cells produce more than 16 zoospores,and the smaller ones produce 4 or 8 zoospores.Vegetative reproduction is by direct cell division in the motile phase and by occasional cell budding in the non-motile phase.There is,as yet,no convincing direct evidence for sexual reproduction. 相似文献
6.
COMBINED EFFECTS OF TEMPERATURE, IRRADIANCE AND SALINITY ON GROWTH OF DIATOM SKELETONEMA COSTATUM 总被引：2，自引：0，他引：2
3-factor experiment was used to study the combined effects of temperature, irradiance and salinity on the growth of an HAB
species diatomSkeletonema costatum (Grev.) Cleve. The results showed that temperature (12, 19, 25, 32 °C), irradiance (0.02, 0.08, 0.3, 1.6)×1016 quanta/(s·cm2)) and salinity (10, 18, 25, 30, 35) significantly influenced the growth of this species. There were interactive effects between
any two of and among all three physical factors on the growth. In the experiment, the most optimal growth condition forS. costatum was temperature of 25°C, salinity of 18–35 and irradiance of 1.6×1016 quanta/(s·cm2). The results indicatedS. costatum could divide at higher rate and were more likely to bloom under high temperature and high illumination from spring to fall.
It was able to distribute widely in ocean and estuary due to its adaptation to a wide range of salinities.
This study was supported by the PREPP and National Key Basic Research Project (2001CB4097) NNSFC No. 39950001, 20177023, 49576301,
49906007 and KZCX2-206. 相似文献
7.
Chondrus is a type of commercially produced red seaweed that widely used for food and carrageen extraction. Although the natural life
history of the alga had been well understood, the factors influencing development of the tetraspore and carpospore remain
poorly understood. In the perspective of seedling resources, the regulation of early development is crucial for the seedling
nursing; therefore, it is necessary to understand the physiological influences during its early development. In this study,
we studied the effects of temperature and irradiance on the early development of Chondrus ocellatus Holm under laboratory conditions. The released tetraspores and carpospores were cultivated at different temperatures (10–28°C)
and irradiances (10, 60 μmol photons m−2s−1) with a photoperiod of 12L:12D. The results indicate that both tetraspores and carpospores are tolerant to temperatures of
10–25°C, and have the highest relative growth rate at 20°C. Irradiance variances influenced the growth of the discoid crusts,
and the influence was more significant with increasing temperature; 60 μmol photons m−2s−1 was more suitable than 10 μmol photons m−2s−1. The optimum temperature and irradiance for the development of seedlings was 20°C and 60 μmol photons m−2s−1, respectively. 相似文献
8.
A filamentous clone of Polysiphonia urceolata was regenerated from segments cut from the fronds of gametophytes. Unlike wild thalli with short virgate branchlets, the clone was filamentous with few branches. Many transparent trichoblasts arose from pericentral cells during the induction culture, but these were seldom observed during normal growth. The trichoblasts were uniseriate, often colorless, and formed lobed rhizoids rapidly when they came into contact with solid substrates. In addition to morphological characteristics, the photosynthetic properties and growth conditions of the clone differed from those of the mother plant. Cross-gradient light and temperature culture experiments revealed that the most favorable conditions for culture of the filamentous clone were 22°C and 95-120 μE/(m2-s) light intensity. The photosynthetic light saturation value for filaments was approx. 100 μE/(m2-s), which is far lower than that of wild thalli. These results could be used to develop techniques for mass cultures of P. urceolata in photobioreactors for production of seed stock or bioactive products. 相似文献
9.
Effects of water temperature （17, 21, 25, 30 and 35℃） and body size （14.75-281.41 g initial body weight） on food consumption, growth, feed conversion, and dry matter content in orange-spotted grouper fed to satiation were investigated. The combined effect of temperature （T, ℃） and body weight （W, g） on maximum food consumption （Cmax, g/day） was described as： InCmax=-7.411＋0.828 InW＋0.317T4）.004 7T2, and the optimum feeding temperature was 33.9℃. The combined effect of temperature and body weight on growth （G） was described as： lnG=-4.461-0.2081nW＋0.394T-0.006 3T^2. The optimum growth temperature was 31.4℃, whereas overall growth rates were high at 25, 30 and 35 ℃. Feed conversion efficiencies （FCE, %）, increasing first and then decreasing with increasing temperature, averaged from 1.8 to 2.1 in terms of dry weight of food fish. The optimum temperature for FCE tended to be lower than that for growth or feeding. Dry matter content increased with both increasing water temperature （17, 25, 30 and 35℃） and body weight, and the combined effect of temperature and body weight on dry matter content （DM, %） was described as： lnDM =3.232＋0.01 4 lnW-0.004 4T＋0.001 2TInW. 相似文献
10.
During a survey for marine microalgal resources, we isolated a rare marine euglenoid from the coastal waters of Qingdao, China in 2009, and established a pure culture. Electron microscopic and molecular phylogenetic (18S rDNA and 16S rDNA sequences) analyses revealed a close affinity with Eutreptiella gymnastica, a bloom-forming species. Different culture conditions were monitored to understand optimal E. gymnastica growth characteristics. The optimal growth conditions in a batch culture of this isolate were 20°C, 160 μmol photons/(m2×s) of white light, and a salinity of 10-31. Nutrient experiments demonstrated that growth increased dramatically with a phosphorus concentration greater than 72 μmol/L. Understanding the effect of culture conditions on E. gymnastica may help understanding the blooming mechanism of this alga in its natural environment. 相似文献
11.
Three new spades and a new variety of nannoplankton, Chrysochromulina papillata, Gaysochromulina chiton var. minuta, Paraphysomonas simplexocorbita and Paraphysomonas bisorbulina are reported in this paper. All were isolated from the preliminary culture samples of seawater collected from Jiaozhou Bay, Shandong, China. The three species occurred at Station 1(120° 14.56′ E, 36°4′N) in November 1984, the new variety at Station 2 (120° 16.35° E,36°4.5′N) in January, 1985. The morphological features, especially the structures of the scales of these new nannoplankton,. are described. The differences between the new species and the related ones are discussed; their movement and nutrition, and the temperature and salinity of their biotopes are also mentioned. 相似文献
12.
In our trials, from 2007 to 2008, of mass production of seedlings of Hizikia fusiformis using synchronization techniques, problems of a "dark thalli" phenomenon and epiphytes contamination severely threatened the health of juvenile seedlings. In this investigation, we optimized conditions for improving the growth of juvenile seedlings. Seven string collectors were seeded with zygotes and a series of experiments were conducted including direct exposure to solar irradiance, co-culture with Ulva spp. and treatment with sodium hypochlorite. It was found that direct exposure to solar irradiance (maximum: 1 740 μmol photons/(m2?s)) for 2 h per day could efficiently enhance the growth of young seedlings and simultaneously inhibit the growth of epiphytic algae. In this treatment, 50-day old seedlings could reach an average of 0.44 cm in length and possess up to nine leaflets. However, a single treatment with 18-mmol/L sodium hypochlorite for 10 min severely harmed 15-day old seedlings. In comparison, weekly treatment with 2.2-mmol/L sodium hypochlorite for 10 min brought no apparent harm to seedlings and eliminated epiphytic algae efficiently. However, this treatment significantly increased the detachment rate of seedlings. Inoculating Ulva spp. onto the collector caused a dramatic decrease in the number of seedlings. However, the growth of the remaining seedlings appeared unhampered. All collectors except the control were daily sprayed with a high pressure water jet from the 8th day post fertilization. From the first day to 50th day, no "dark thallus" was observed on any of the seven collectors. We believe that well-timed daily exposure to solar irradiance would favor H. fusiformis in its early growing stages. 相似文献
13.
This study deals with contribution of artificial food pellet and natural food to Chinese prawn (Penaeus orientalis) growth in a semiintensive culture pond. The prawn carbon consumption, budget, and the effects of some factors on the budget were investigated. The results showed that 26.2% of P. orientalis growth carbon came from formulated feed at the initial culture stage (when the prawns were 0.06±0.01 g in wet weight), and was 62.5% when the prawns were 9.56±1.04 g. The remaining part of the growth carbon was derived from organic fertilizer and natural food. The highest growth rate occurred at 20×10-3 salinity. Suitable salinity for culturing Chinese prawn was (20-28)×10-3. 相似文献
14.
The aim of this study is to isolate protoplasts from Undaria pinnatifida. Protoplasts of the alga were isolated enzymatically by using alginate lyase, which was prepared by fermenting culture of
a strain Vibrio sp. 510. Monofacterial method was applied for optimizing digestion condition. The optimum condition for protoplast preparation
is enzymatic digestion at 28°C for 2h using alginate lyase at the concentration of 213.36 U (8 mL) every 0.5g fresh thalline
with NaCl 50 and at the shaking speed of 150 r min−1 during digestion. The protoplast yield can reach 2.62±0.09 million per 0.5 g fresh leave under the optimum condition. The
enzyme activity is inhibited by Ca2+ and slightly enhanced by Fe2+ and Mn2+ at concentrations of 0.05, 0.08 and 0.10 mol L−1. 相似文献
15.
Pyropia yezoensis(formerly Porphyra yezoensis) is an economically important red alga that is cultured extensively in China. The red rot disease occurs commonly during Pyropia cultivation,causing serious economic losses. An incidence of red rot disease was found in a P. yezoensis farm from mid-November to mid-December 2015 at Lianyungang, Jiangsu Province, China. Histopathological examination revealed that the naturally infected thalli were infected apparently by a pathogen, leading to red rot symptoms. The causative agent was isolated and identified as the oomycete Pythium chondricola by morphological analysis and sequence analysis of the internal transcribed spacer and cytochrome oxidase subunit 1(cox1). In artificial infection experiments on the P. yezoensis blades, the P. chondricola isolate was able to cause the same characteristic histopathology seen in natural infections. P. chondricola grew well at a wide range of temperatures in the range 8-31℃, salinities at 0-45 and pH 5-9. In an orthogonal test used to determine the effects of environmental factors(temperature, salinity, and zoospore concentration)on infection, the data revealed that temperature was the most important factor to affect red rot disease development, with the optimal conditions for disease expansion being 20℃, 35 salinity, and a zoospore concentration of 10~6 zoospores/mL. The results obtained from the present study prompted us to set up a comprehensive epidemiological study on Pyropia, which will provide support to maintain the healthy development of the Pyropia industry in China. 相似文献
16.
A laboratory experiment was conducted to assess the bioaccumulation of Pb2+ and its effects on growth, morphology and pigment contents of Spirulina (Arthrospira) platensis. The specimen cultured in Zarrouk liquid medium was treated with various initial metal concentrations (0, 5, 10, 30, 50 and
100 μg mL−1). The growth of S. platensis was adversely affected by Pb2+ at high concentrations (30, 50 and 100 μg mL−1). However, at low concentrations (5 μg mL−1), Pb2+ could stimulate its growth slightly. The pigment contents (chlorophyll α and β carotene) were decreased in a dose-dependent
manner. The highest reductions (67% and 53% respectively in chlorophyll α and β carotene) were observed in 100 μg mL−1 treatment group. The LC50 (96 h) of Pb2+ was measured as 75.34 μg mL−1. Apart from a few cases of filament breakages at elevated concentrations (50 and 100 μg mL−1), morphological abnormalities are not specific. Metal bioaccumulation increased with Pb2+ concentrations, but decreased with exposure time. The maximum accumulated amount was 188 mg g−1 dry weight. The bioconcentration factor (BCF) reached to a peak at day 2, followed by a gradual reduction for all the exposure
concentrations. S. platensis is able to tolerate considerably high Pb2+ concentrations. Consequently it can be used as a potential species to remove heavy metal from contaminated waters. 相似文献
17.
The marine yeast strain N13d, producing an extracellular amylase, was isolated from the deep sea sediments of the Pacific
Ocean. This strain was identified to be Aureobasidium pullulans by 18S rRNA gene sequence analysis and routine yeast identification methods. The optimal sea water medium for amylase production
by this yeast strain was 1.0% peptone and 1.0% soluble starch with pH 4.0. The optimal conditions for amylase production by
this yeast strain were with temperature 28 °C, aeration rate 6 Lmin−1 and agitation speed 250 rmin−1. Under these conditions, 58.5 units of amylase activity per mg protein were produced within 56 h of fermentation. 相似文献
18.
Algal allelopathy is a manifold ecological/physiological phenomenon that is focused on chemical interactions and autotoxicity. We investigated the allelopathic interactions between Karenia mikimotoi and Dunaliella salina in laboratory cultures based on diff erent temperature (15°C, 20°C, and 25°C) and lighting (40, 80, and 160 μmol/(m2·s)) conditions. The growth of D. salina in bi-algae culture (1:1 size/density) was significantly restrained. The results of cell-free filtrate culture indicate that direct cell-tocell contact was not necessary in interspecific competition. Further experimental results demonstrated that allelochemicals released from K. mikimotoi were markedly influenced by both temperature (P =0.013) and irradiance (P =0.003), resulting in diff erent growth characteristics of D. salina in filtrate mediums. Compared with the plateau period, K. mikimotoi exudates in the exponential phase had a stronger short-term inhibition effect on D. salina in normal conditions. A clear concentration-dependent relationship was observed in the effect of allelochemicals released from K. mikimotoi with low-promoting and high-repressing effects on D. Salina in a short time-scale. In addition, allelopathic substances remain stable and effective under high temperature and pressure stress. Many flocculent sediments adhering with D. salina cells were observed in all filtrate mediums, while the quantity and color depended on the original culture conditions. 相似文献
19.
The meiotic process in Noctiluca scintillans were observed under light microscope.Some abnormal cell divisions, incompletely separated “zoospores” and the changes of the zoospores are described in this paper. Together with the fmdings of field samplings and the previous results by other researchers, the process of meiosis in N. scintillans was supposed to be a pathway to reduce the extra high density of NH3-N within the cell in order to ensure normal population growth. 相似文献
20.
The effects of several nutritional factors on the growth and eicosapentaenoic acid (EPA) production of diatom Nitzschia laevis were studied. 4 LDM (quadrupled concentration of the nutrient salt) was the optimal concentration of nutrient salt for the
growth and EPA production of N. laevis. The growth of N. laevis was inhibited when the glucose concentration was either lower than 10 gL−1 or higher than 15 gL−1. Both sodium nitrate and urea were good nitrogen sources for the growth and EPA production, while ammonium chloride seriously
decreased the dry cell weight (DW) and the EPA content. Silicate seriously influenced the growth of N. laevis. The maximum DW of 2.34 gL−1 was obtained in the presence of 150 mgL−1 Na2SiO3·9H2O. The EPA content remained almost the same when the silicate concentration was lower than 150 mgL−1; however, higher silicate concentrations resulted in a steady decrease of EPA content. Low medium salinity (⩽29) did not
seem to influence the DW of N. laevis, and high salinity resulted in a decrease of DW. The highest EPA content (4.08%) and yield (110 mgL−1) were observed at the salinity of 36 and 29, respectively. 相似文献