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Study on diel rhythm of chlorophyll a and photosynthesis in nearshore waters of Qingdao
Mao Xinghua, Zhu Mingyuan, Yang Xiaolong, Hao Yawei, John Cullen
1998(2): 243-254.
Keywords: Phytoplankton, Chl a, photosynthesis, diel rhythm
A study was made on the dial rhythm and variation of Chl a and photosynthesis in the nearshore of qingdao. Both Chl a and photosynthesis show obvious dial rhythm; the peak value of surface Chl a appeared in the afternoon,while bottom Chl a around noon;the maximum value of photosynthetic rate appeared in the morning, noon and afternoon. The scope of the diet rhythm of Chl a and photosynthesis and the time for the appearance of the peak value varied in different months. Moreover, the mechanism of the formation of this diet rhythm is also discussed in this paper.
Altered seawater salinity levels affected growth and photosynthesis of Ulva fasciata (Ulvales, Chlorophyta) germlings
CHEN Binbin, ZOU Dinghui
2015, 34(8): 108-113. doi: 10.1007/s13131-015-0654-3
Keywords: salinity stress, Ulva fasciata, germlings, photosynthesis, growth, malondialdehyde
Seawater salinity is greatly influenced by tide, evaporation and rain falls. In this study, we investigated the growth and photosynthetic responses of zygote-derived Ulva fasciata Delile germlings to short-term (minutes) and prolonged (days) exposure to different salinity gradients, to evaluate the effect of salinity variation on the early stage of life history in this seaweed. The results showed that, the maximum net photosynthetic rates (NPRm) of U. fasciata germlings was observably decreased in desalted (25 and 15) and high (45) salinity seawater in short-term exposure tests (in minutes). However, after 30 min, the photosynthesis activity in medium salinity (25) was maintained at a relative high level (above 70%). After 8 d prolonged culture, the photosynthesis and mean relative growth rate (RGR) of germlings were all markedly lowered, whereas the malondialdehyde (MDA) contents increased as the salinity desalted from 34 to 15. The salinity decrease from 34 to 25 had no significant effect on the RGR, but obviously influenced the morphology of the germlings. High salinity level (45) significantly depressed the RGR and photosynthesis of U. fasciata germlings, while it notably increased the MDA contents. The results showed that the salinity elevation had more detrimental effects on Ulva fasciata germlings than salinity decrease did. The germlings grown at the salinity seawater levels from 25 to 34, performed preferable photosynthetic acclimation both in temporary and prolonged culture. Broad salinity tolerance from 25 to 34 in U. fasciata germlings may have partly evolved as a response to regular diurnal tides.
Ecophysiological characteristics of four intertidal marine macroalgae during emersion along Shantou coast of China, with a special reference to the relationship of photosynthesis and CO2
ZOU Dinghui, GAO Kunshan
2005(3): 105-113.
Keywords: marine macroalgae, ecophysiology, photosynthesis, CO2, zonation
Intertidal marine macroalgae experience periodical exposures during low tide due to their zonational distribution. The duration of such emersion leads to different exposures of the plants to light and aerial CO2, which then affect the physiology of them to different extents.The ecophysiological responses to light and CO2 were investigated during emersion in two red algae Gloiopeltis furcata and Gigartina intermedia, and two brown algae Petaloniafascia and Sargassum hemiphyllum, growing along the Shantou coast of China. The light-saturated net photosynthesis in G. furcata and P. fascia showed an increase followed by slightly desiccation, whereas that in G.intermedia and S. hemiphyllum exhibited a continuous decrease with water loss. In addition, the upper-zonated G. furcata and P. fascia,exhibited higher photosynthetic tolerance to desiccation and required higher light level to saturate their photosynthesis than the lower-zonated G. intermedia and S. hemiphyllum. Desiccation had less effect on dark respiration in these four algae compared with photosynthesis. The light-saturated net photosynthesis increased with increased CO2 concentrations, being saturated at CO2 concentrations higher than the present atmospheric level in G. furcata, G. intermedia and S. hemiphyllum during emersion. It was evident that the relative enhancement of photosynthesis by elevated CO2 in those three algae increased, though the absolute values of photosynthetic enhancement owing to CO2 increase were reduced when the desiccation statuses became more severe. However, in the case of desiccated P. fascia (water loss being greater than 20%), light saturated net photosynthesis was saturated with current ambient atmospheric CO2 level. It is proposed that increasing atmospheric CO2 will enhance the daily photosynthetic production in intertidal macroalgae by varied extents that were related to the species and zonation.
Effect of temperature, salinity and irradiance on growth and photosynthesis of Ulva prolifera
XIAO Jie, ZHANG Xiaohong, GAO Chunlei, JIANG Meijie, LI Ruixiang, WANG Zongling, LI Yan, FAN Shiliang
2016, 35(10): 114-121. doi: 10.1007/s13131-016-0891-0
Keywords: Ulva prolifera, green tide, photosynthesis, growth rate, temperature, salinity
Intensive Pyropia aquaculture in the coast of southwestern Yellow Sea and its subsequent waste, including disposed Ulva prolifera, was speculated to be one of the major sources for the large-scale green tide proceeding in the Yellow Sea since 2007. It was, however, unclear how the detached U. prolifera responded and resumed growing after they detached from its original habitat. In this study, we investigated the growth and photosynthetic response of the detached U. prolifera to various temperature, salinity and irradiance in the laboratory. The photosynthetic rate of the detached U. prolifera was significantly higher at moderate temperature levels (14-27℃) and high salinity (26-32), with optimum at 23℃ and 32. Both low (<14℃) and highest temperature (40℃), as well as low salinity (8) had adverse effects on the photosynthesis. Compared with the other Ulva species, U. prolifera showed higher saturated irradiance and no significant photoinhibition at high irradiance, indicating the great tolerance of U. prolifera to the high irradiance. The dense branch and complex structure of floating mats could help protect the thalli and reduce photoinhibition in field. Furthermore, temperature exerted a stronger influence on the growth rate of the detached U. prolifera compared to salinity. Overall, the high growth rate of this detached U. prolifera (10.6%-16.7% d-1) at a wide range of temperature (5-32℃) and salinity (14-32) implied its blooming tendency with fluctuated salinity and temperature during floating. The environmental parameters in the southwestern Yellow Sea at the beginning of green tide were coincident with the optimal conditions for the detached U. prolifera.
The effects of immobilization on physiology and ultrastructure of unicellular alga Platymonas subcordiformis
Zhang Xuecheng, Wu Xiaonan, Li Yonghong
1995(2): 269-275.
Keywords: Platymonas subcordiformis, immobilization, photosynthesis, respiration, ultrastructure
In the present paper, the unicellular green alga Platymonas subcordiformis was entrapped in 2% (W/V) alginate, treated with CaCl2 at different concentrations (0.5, 0.75, 1.0, 1.5 and 2.0 mol/dm3), cultured at 15℃ and 25℃.The growth rate and morphology were studied and photosynthesis and respiration rates were measured.The optimum conditions of immobilized culture is in 0.5 mol/dm3 of CaCl2, at 25℃.Photosynthesis rate of immobilized cells is higher than free cultivated cells, and that at 15℃ than at 25℃.Under scanning electropic microscope, it was shown that the immobilized cells had larger size and rougher surface.The relationship between growth of immobilized cells and abiotic factors and the prospects of applying immobilized cultivation are also discussed.
The effects of elevated-CO2 on physiological performance of Bryopsis plumosa
YILDIZ Gamze, DERE Şükran
2015, 34(4): 125-129. doi: 10.1007/s13131-015-0652-5
Keywords: Bryopsis plumosa, chlorophyll fluorescence, ocean acidification, photosynthesis
An increase in the level of atmospheric carbon dioxide (CO2) and the resultant rise in CO2 in seawater alter the inorganic carbon concentrations of seawater. This change, known as ocean acidification, causes lower pH in seawater and may affect the physiology of seaweed species. Accordingly, the main goal of the current study was to determine the physiological responses of Bryopsis plumosa to elevated-CO2. The results indicated that photosynthesis of B. plumosa was insignificantly affected to elevated-CO2, but photosynthetic pigment contents and phenolics were significantly decreased. The results obtained from the research reveal that B. plumosa may become physiologically advanced when exposed to CO2-induced ocean acidification. In particular, B. plumosa may be more able to compete with calcifying algae when it will become future predicted CO2 scenario.
Oxidative stress responses to cadmium in the seedlings of a commercial seaweed Sargassum fusiforme
Tiantian Zhang, Minheng Hong, Mingjiang Wu, Binbin Chen, Zengling Ma
2020, 39(10): 147-154. doi: 10.1007/s13131-020-1630-0  Published:2020-10-25
Keywords: Sargassum fusiforme, cadmium stress, oxidation resistance, photosynthesis, aquaculture, marine pollution
Cadmium (Cd) is a common heavy metal pollutant in the aquatic environment, generally toxic to plant growth and leading to growth inhibition and biomass reduction. To study the oxidation resistance in Sargassum fusiforme seedlings in response to inorganic Cd stress, we cultured the seedlings under two different Cd levels: natural seawater and high Cd stress. High Cd stress significantly inhibited the seedlings growth, and darkened the thalli color. Additionally, the pigment contents, growth rate, peroxidase (POD) activity, dehydroascorbic acid (DHA) content, and glutathione reductase (GR) activity in S. fusiforme were significantly reduced by high Cd treatment. Contrarily, the Cd accumulation, Cd2+ absorption rate, dark respiration/net photosynthetic rate (Rd/Pn), ascorbic acid (Vc) content, soluble protein (SP) content, glutathione (GSH), and the activities of superoxide dismutase (SOD) and catalase (CAT) of S. fusiforme under Cd treatment significantly increased compared to the control group. The decrease of malondialdehyde (MDA) was not significant. Although S. fusiforme seedlings increased the antioxidant activities of POD, SOD, Vc, and the AsA-GSH cycle to disseminate H2O2 and maintain healthy metabolism, high Cd stress caused Cd accumulation in the stem and leaves of S. fusiforme seedlings. The excessive Cd significantly restricted photosynthesis and reduced photosynthetic pigments in the seedlings, resulting in growth inhibition and deep morphological color, especially of the stems. High levels of Cd in seawater had toxic effects on commercial S. fusiforme seedlings, and risked this edible seaweed for human food.
RELATIONSHIP BETWEEN PHOTOSYNTHESIS OR RESPIRATION OF SOME SEAWEEDS AND TEMPERATURE OR SALINITY
HUANG LIANGMIN
1986(2): 291-299.
The effect of temperature and salinity on the photosynthetic and respiratory rates of some seaweeds are reported.The regression equations for the seaweeds and their correlograms are discussed and compared.
The results indicate that the photosynthetic rate of E.binghamiae fronds shows a significant negative linear correlation (p<0.01) with changing of temperature (20-35℃),the optimum temperature being 20℃,while for the others there is a conic correlation between photosynthetic rate and temperature.The optimum temperature for photosynthesis is 23-25℃ for two species of Porphyra fronds,25-28℃ for Gracilaria sp.thalli and 23-30℃ for V.conglobata and S.hemiphyllum fronds,separately.The rates of respiration for all the studied species increase linearly with increasing temperature from 18 to 35℃.The optimum salinities for photosynthesis range from 26 to 32 for two species of Gracilaria,whose respiratory rates decrease gradually with increasing salinity.
Physiological performance of three calcifying green macroalgae Halimeda species in response to altered seawater temperatures
Zhangliang Wei, Jiahao Mo, Ruiping Huang, Qunju Hu, Chao Long, Dewen Ding, Fangfang Yang, Lijuan Long
2020, 39(2): 89-100. doi: 10.1007/s13131-019-1471-3  Published:2020-02-25
Keywords: calcifying macroalgae, climate change, seawater temperature, physiological performance, photosynthesis, calcification
The effects of seawater temperature on the physiological performance of three Halimeda species were studied for a period of 28 d. Five treatments were established for Halimeda cylindracea, Halimeda opuntia and Halimeda lacunalis, in triplicate aquaria representing a factorial temperature with 24°C, 28°C, 32°C, 34°C and 36°C, respectively. The average Fv/Fm of these species ranged from 0.732 to 0.756 between 24°C and 32°C but declined sharply between 34°C (0.457±0.035) and 36°C (0.122±0.014). Calcification was highest at 28°C, with net calcification rates (Gnet) of (20.082±2.482) mg/(g·d), (12.825±1.623) mg/(g·d) and (6.411±1.029) mg/(g·d) for H. cylindracea, H. opuntia and H. lacunalis, respectively. Between 24°C and 32°C, the specific growth rate (SGR) of H. lacunalis (0.079%–0.110% d–1) was lower than that of H. cylindracea (0.652%–1.644% d–1) and H. opuntia (0.360%–1.527% d–1). Three Halimeda species gradually bleached at 36°C during the study period. Malondialdehyde (MDA) and proline levels in tissues of the three Halimeda were higher in 34–36°C than those in 24–32°C. The results indicate that seawater temperature with range of 24–32°C could benefit the growth and calcification of these Halimeda species, however, extreme temperatures above 34°C have negative impacts. The measured physiological parameters also revealed that H. cylindracea and H. opuntia displayed broader temperature tolerance than H. lacunalis.
Effects of light, temperature and nutrients on photosynthesis of Biddulphia regia
Li Wenquan, Zheng Airong, Wang Xian, Chen Qinghua
1996(1): 127-131.
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