In order to study the complex effects of photoperiod,temperature,and light intensity on the spore maturation and release number of Ulva prolifera,we cultured thalli segment(2–3 mm)under three different photoperiods(L...In order to study the complex effects of photoperiod,temperature,and light intensity on the spore maturation and release number of Ulva prolifera,we cultured thalli segment(2–3 mm)under three different photoperiods(L:D=12:12,14:10 and 10:14),temperature(15℃(LT),25℃(MT)and 30℃(HT))and light intensity(100,200 and 400μmol m^(−2)s^(−1),noted as LL,ML and HL,respectively)conditions.Then the maturation time,spore release number and chlorophyll fluorescence were analyzed.The results suggested that:1)The spore maturation time was accelerated by higher temperature or higher light intensity from 62 h to 36 h,and changes in day length accelerated the spore maturation to a certain extent as compared with 12:12 light/dark cycle;2)Higher light intensity significantly decreased the chlorophyll fluorescence(Fv′/Fm′,NPQ,rETRmax andα)of the mature reproductive segment under 30℃with 12:12 light/dark cycle.But when in the other photoperiods(10:14 and 14:10 conditions),the inhibitory effects of high light intensity were alleviated significantly;3)The optimum condition for the spore maturation and release was 12:12 light/dark cycle,25℃,400μmol m^(−2)s^(−1),with both shorter and longer photoperiod reducing the spore release number;4)Higher light intensity significantly increased the spore release number under 25℃,but these effects were alleviated by 30℃treatment.This study is the first attempt to elucidate the coincidence effects of photoperiod,temperature and light intensity on the reproduction of Ulva,which would help to reveal the mechanism of the rapid proliferation of green tide.展开更多
Abstract Many species of microalga Dunaliella exhibit a remarkable tolerance to salinity and are therefore ideal for probing the effects of salinity. In this work, we assessed the effects of NaC1 stress on the growth,...Abstract Many species of microalga Dunaliella exhibit a remarkable tolerance to salinity and are therefore ideal for probing the effects of salinity. In this work, we assessed the effects of NaC1 stress on the growth, activity and mRNA level of carbon and nitrogen metabolism enzymes of D. viridis. The alga could grow over a salinity range of 0.44 mol L-t to 3.00 mol L-1 NaCI, but the most rapid growth was observed at 1.00molL-1NaC1, followed by 2.00 molL-l NaC1. Paralleling these growth patterns, the highest initial and total Rubisco activities were detected in the presence of 1.00molL-t NaC1, decreasing to 37.33% and 26.39% of those values, re- spectively, in the presence of 3.00 mol L-1 NaC1, respectively. However, the highest extracellular carbonic anhydrase （CA） activity was measured in the presence of 2.00molL-1 NaC1, followed by 1.00molL-1NaC1. Different from the two carbon enzymes, nitrate reductase （NR） activity showed a slight change under different NaC1 concentrations. At the transcriptional level, the mRNAs of Rubisco large subunit （rbcL）, and small subunit （rbcS）, attained their highest abundances in the presence of 1.00 and 2.00molL-1 NaC1, respectively. The CA mRNA accumulation was induced from 0.44molL ~ to 3.00molL-1 NaC1, but the NR mRNA showed the decreasing tendency with the increasing salinity. In conclusion, the growth and carbon fixation enzyme of Rubisco displayed similar tendency in response to NaC1 stress, CA was proved be salt-inducible within a certain salinity range and NR showed the least effect by NaC1 in D. viridis.展开更多
The optimum concentration of Na_2 WO_4 was explored in relation to the cell density and astaxanthin content in Haematococcus pluvialis. Then, the cellular morphology, nitrate reductase(NR) activity, soluble sugar and ...The optimum concentration of Na_2 WO_4 was explored in relation to the cell density and astaxanthin content in Haematococcus pluvialis. Then, the cellular morphology, nitrate reductase(NR) activity, soluble sugar and protein contents, and chlorophyll ?uorescence were measured, and the transcriptional expression of carotenogenic genes was determined by quantitative real-time PCR. The results showed that 3.0 mmol/L of Na_2 WO_4 was the optimum concentration to induce astaxanthin accumulation, with a maximum content of 49.41±0.13 pg/cell reached on the tenth day. The NR activity decreased signi?cantly and continually after Na_2 WO_4 treatment. The soluble sugar content increased gradually during the experimental period and was eventually signi?cantly higher than that in the control. The soluble protein content increased rapidly,reached a maximum in day 0.5 and day 1 and then decreased. The ef fective photochemical effciency of PSII( F v'/F m') and light saturation( E k) ?rst decreased and then tended to stabilize, and NADP +-glyceraldehyde-3-phosphate dehydrogenase(GAPDH) gene expression was correlated with photosynthesis. The transcriptional expression of ipi, psy and bkt was signi?cantly increased compared with that in the control after application of Na_2 WO_4, and the relative expression of ipi reached the highest level on the ?fth day, with a 98.03±1.92-fold increase. Our results describe a new approach to promote the ef fective accumulation of astaxanthin in H. pluvialis by NR inhibitor Na_2 WO_4.展开更多
Xiangshan bay is a narrow semi-closed bay and situated on the northwestern coast of the East China Sea. Over past decades, it has become to a major bay with intensive human activities, dense urbanized area, and poor w...Xiangshan bay is a narrow semi-closed bay and situated on the northwestern coast of the East China Sea. Over past decades, it has become to a major bay with intensive human activities, dense urbanized area, and poor water quality. The aim of this paper was to reveal the ecological status through the elucidation of the species composition, abundance, biomass and diversity of macrobenthos in this bay. Six intertidal sections were surveyed from January 2007 to November 2008 quarterly. Sections TG, HD and XH are located in the three inner bays, sections QJ and WS are located near the thermal power plants, and section XX is located at the outer part of Xiangshan Bay. Great variations in macrobenthos community were indentified, and the species composition of the community in the present study showed the dominance in the order of molluscs （bivalves and gastropods）, crustaceans and others, and only few Polychaeta were recorded. Only three dominant species, Littorina brevicula, llyplax tansuiensis, and Cerithidea cingu- lata were collected in all the sections, and a total of 19 dominant species were recorded only in one section. Two-way ANOVA analyses of abundance indicated that there were significant differences among sections or seasons. Shannon-Wiener diversity index （H＇） had its maximum （2.45） in section QJ, and minimum （1.76） in section TG Multiple irregular k-dominance plots clearly showed that the study area was polluted and the macrobenthos community was under stress. We conclude that the macrobenthos of Xiang- shan Bay have been disturbed by human activities, especially at the interior bay.展开更多
基金supported by the Natural Science Foundation of Zhejiang Province(No.LY23D060003)the Key Program of Science and Technology Innovation in Ningbo(2021Z114,2023Z118)sponsored by K.C.Wong Magna Fund in Ningbo University.
文摘In order to study the complex effects of photoperiod,temperature,and light intensity on the spore maturation and release number of Ulva prolifera,we cultured thalli segment(2–3 mm)under three different photoperiods(L:D=12:12,14:10 and 10:14),temperature(15℃(LT),25℃(MT)and 30℃(HT))and light intensity(100,200 and 400μmol m^(−2)s^(−1),noted as LL,ML and HL,respectively)conditions.Then the maturation time,spore release number and chlorophyll fluorescence were analyzed.The results suggested that:1)The spore maturation time was accelerated by higher temperature or higher light intensity from 62 h to 36 h,and changes in day length accelerated the spore maturation to a certain extent as compared with 12:12 light/dark cycle;2)Higher light intensity significantly decreased the chlorophyll fluorescence(Fv′/Fm′,NPQ,rETRmax andα)of the mature reproductive segment under 30℃with 12:12 light/dark cycle.But when in the other photoperiods(10:14 and 14:10 conditions),the inhibitory effects of high light intensity were alleviated significantly;3)The optimum condition for the spore maturation and release was 12:12 light/dark cycle,25℃,400μmol m^(−2)s^(−1),with both shorter and longer photoperiod reducing the spore release number;4)Higher light intensity significantly increased the spore release number under 25℃,but these effects were alleviated by 30℃treatment.This study is the first attempt to elucidate the coincidence effects of photoperiod,temperature and light intensity on the reproduction of Ulva,which would help to reveal the mechanism of the rapid proliferation of green tide.
基金funded by the Project of Science and Technology Innovation Team of Zhejiang Province (2010R50025-25)sponsored by the K. C. Wong Magna Fund
文摘Abstract Many species of microalga Dunaliella exhibit a remarkable tolerance to salinity and are therefore ideal for probing the effects of salinity. In this work, we assessed the effects of NaC1 stress on the growth, activity and mRNA level of carbon and nitrogen metabolism enzymes of D. viridis. The alga could grow over a salinity range of 0.44 mol L-t to 3.00 mol L-1 NaCI, but the most rapid growth was observed at 1.00molL-1NaC1, followed by 2.00 molL-l NaC1. Paralleling these growth patterns, the highest initial and total Rubisco activities were detected in the presence of 1.00molL-t NaC1, decreasing to 37.33% and 26.39% of those values, re- spectively, in the presence of 3.00 mol L-1 NaC1, respectively. However, the highest extracellular carbonic anhydrase （CA） activity was measured in the presence of 2.00molL-1 NaC1, followed by 1.00molL-1NaC1. Different from the two carbon enzymes, nitrate reductase （NR） activity showed a slight change under different NaC1 concentrations. At the transcriptional level, the mRNAs of Rubisco large subunit （rbcL）, and small subunit （rbcS）, attained their highest abundances in the presence of 1.00 and 2.00molL-1 NaC1, respectively. The CA mRNA accumulation was induced from 0.44molL ~ to 3.00molL-1 NaC1, but the NR mRNA showed the decreasing tendency with the increasing salinity. In conclusion, the growth and carbon fixation enzyme of Rubisco displayed similar tendency in response to NaC1 stress, CA was proved be salt-inducible within a certain salinity range and NR showed the least effect by NaC1 in D. viridis.
基金Supported by the National Natural Science Foundation of China(No.31572638)the Public Benefit Program of Zhejiang Science and Technology Department(No.2015C32021)+4 种基金the Program of Ningbo Science and Technology Bureau(No.2014C10023)the NSF of Ningbo Government(No.2015A610265)the Project of Science and Technology Innovation for College Students in Zhejiang Province(No.2016R405078)the K.C.Wong Magna Fund in Ningbo Universitythe Subject Project of Ningbo University(No.xkl1526)
文摘The optimum concentration of Na_2 WO_4 was explored in relation to the cell density and astaxanthin content in Haematococcus pluvialis. Then, the cellular morphology, nitrate reductase(NR) activity, soluble sugar and protein contents, and chlorophyll ?uorescence were measured, and the transcriptional expression of carotenogenic genes was determined by quantitative real-time PCR. The results showed that 3.0 mmol/L of Na_2 WO_4 was the optimum concentration to induce astaxanthin accumulation, with a maximum content of 49.41±0.13 pg/cell reached on the tenth day. The NR activity decreased signi?cantly and continually after Na_2 WO_4 treatment. The soluble sugar content increased gradually during the experimental period and was eventually signi?cantly higher than that in the control. The soluble protein content increased rapidly,reached a maximum in day 0.5 and day 1 and then decreased. The ef fective photochemical effciency of PSII( F v'/F m') and light saturation( E k) ?rst decreased and then tended to stabilize, and NADP +-glyceraldehyde-3-phosphate dehydrogenase(GAPDH) gene expression was correlated with photosynthesis. The transcriptional expression of ipi, psy and bkt was signi?cantly increased compared with that in the control after application of Na_2 WO_4, and the relative expression of ipi reached the highest level on the ?fth day, with a 98.03±1.92-fold increase. Our results describe a new approach to promote the ef fective accumulation of astaxanthin in H. pluvialis by NR inhibitor Na_2 WO_4.
基金financial support from the Ningbo Science and Technology Bureau and the Ningbo Oceanology and Fishery Bureau for Technology and Research of Marine Ecological Environmental Protection and Restoration of Xiangshan Bay (No. 2006C 10030)
文摘Xiangshan bay is a narrow semi-closed bay and situated on the northwestern coast of the East China Sea. Over past decades, it has become to a major bay with intensive human activities, dense urbanized area, and poor water quality. The aim of this paper was to reveal the ecological status through the elucidation of the species composition, abundance, biomass and diversity of macrobenthos in this bay. Six intertidal sections were surveyed from January 2007 to November 2008 quarterly. Sections TG, HD and XH are located in the three inner bays, sections QJ and WS are located near the thermal power plants, and section XX is located at the outer part of Xiangshan Bay. Great variations in macrobenthos community were indentified, and the species composition of the community in the present study showed the dominance in the order of molluscs （bivalves and gastropods）, crustaceans and others, and only few Polychaeta were recorded. Only three dominant species, Littorina brevicula, llyplax tansuiensis, and Cerithidea cingu- lata were collected in all the sections, and a total of 19 dominant species were recorded only in one section. Two-way ANOVA analyses of abundance indicated that there were significant differences among sections or seasons. Shannon-Wiener diversity index （H＇） had its maximum （2.45） in section QJ, and minimum （1.76） in section TG Multiple irregular k-dominance plots clearly showed that the study area was polluted and the macrobenthos community was under stress. We conclude that the macrobenthos of Xiang- shan Bay have been disturbed by human activities, especially at the interior bay.
