作者机构：
[Qiu, Baosheng] Cent China Normal Univ, Coll Life Sci, Wuhan 430079, Hubei, Peoples R China.;Cent China Normal Univ, Hubei Key Lab Genet Regulat & Integrat Biol, Wuhan 430079, Hubei, Peoples R China.
通讯机构：
[Qiu, Baosheng] C;Cent China Normal Univ, Coll Life Sci, Wuhan 430079, Hubei, Peoples R China.
摘要：
Liu Y., Yu L., Ke W., Gao X. and Qiu B. 2010. Photosynthetic recovery of Nostoc flagelliforme (Cyanophyceae) upon rehydration after 2 years and 8 years dry storage. Phycologia 49: 429–437. DOI: 10.2216/09-01.1 The photosynthetic recovery of Nostoc flagelliforme (Berkeley & Curtis) Bornet & Flahault upon rehydration was investigated with the 2-year and 8-year dried samples. It was found that the 2-year sample absorbed water much faster compared with the 8-year sample during 3–24-h rehydration. The 2-year sample recovered its photosynthesis and respiration fully upon 24-h rehydration. However, the 8-year sample almost lost its ability to recover dark respiration, net photosynthetic activity, maximal quantum yield and photosystem II (PSII) electron transport activity. The F645/F685 ratio of the 8-year sample increased significantly from 1.70 to 3.09 during 24-h rehydration, which suggested damage to the coupling between phycobiliprotein and the PSII reaction centers. The 8-year sample retained PSI activity during rehydration, although it had almost lost PSII activity. The PSI electron transport activity of the 8-year sample was comparable to that of the 2-year sample. The up-regulation of psbD and petB transcripts in the 2-year sample was the most rapid during rehydration and then in the order: rbcL, rbcX and psaA; psbA2 and psaB; psbA1. For the 8-year sample, the initial transcript abundances of rbcL, rbcX, psbA1, psbA2, psbD, petB, psaB and psaA were, respectively, 56%, 17%, 4%, 10%, 16%, 4%, 36% and 7% of the 2-year sample. The production rate of intracellular reactive oxygen species (ROS) and ion leakage of the 8-year sample were significantly higher than those of the 2-year sample. When the 2-year and 8-year samples were taken together, a good linear correlation could be established between the production of intracellular ROS and ion leakage.
摘要：
Synechococcus species are important primary producers in coastal and open-ocean ecosystems. When nitrate was provided as the sole nitrogen source, nickel starvation inhibited the growth of strains WH8102 and WH7803, while it had little effect on two euryhaline strains, WH5701 and PCC 7002. Nickel was required for the acclimation of Synechococcus WH7803 to low iron and high light. In WH8102 and WH7803, nickel starvation decreased the linear electron transport activity, slowed down QA reoxidation, but increased the connectivity factor between individual photosynthetic units. Under such conditions, the reduction of their intersystem electron transport chains was expected to increase, and their cyclic electron transport around PSI would be favored. Nickel starvation decreased the total superoxide dismutase (SOD) activity of WH8102 and WH7803 by 30% and 15% of the control, respectively. The protein-bound 63Ni of the oceanic strain WH8102 comigrated with SOD activity on nondenaturing gels and thus provided additional evidence for the existence of active NiSOD in Synechococcus WH8102. In WH7803, it seems likely that nickel starvation affected other metabolic pathways and thus indirectly affected the total SOD activity.
摘要：
Effects of two fertilizers, NH(4)Cl and KCl, on the growth of the edible cyanobacterium Ge-Xian-Mi (Nostoc) and four other cyanobacterial strains were compared at pH 8.3+/-0.2 and 25 degrees C. Their growth was decreased by at least 65% at 10 mmol L(-1) NH(4)Cl but no inhibitory effect was observed at the same level of KCl. Meanwhile, the strains exhibited a great variation of sensitivity to NH(4)(+) toxicity in the order: Ge-Xian-Mi>Anabaena azotica FACHB 118>Microcystis aeruginosa FACHB 905>M. aeruginosa FACHB 315>Synechococcus FACHB 805. The 96-h EC(50) value for relative growth rate with regard to NH(4)(+) for Ge-Xian-Mi was 1.105 mmol L(-1), which was much less than the NH(4)(+) concentration in many agricultural soils (2-20 mmol L(-1)). This indicated that the use of ammonium as nitrogen fertilizer was responsible for the reduced resource of Ge-Xian-Mi in the paddy field. After 96 h exposure to 1 mmol L(-1) NH(4)Cl, the photosynthetic rate, F(v)/F(m) value, saturating irradiance for photosynthesis and PSII activity of Ge-Xian-Mi colonies were remarkably decreased. The chlorophyll synthesis of Ge-Xian-Mi was more sensitive to NH(4)(+) toxicity than phycobiliproteins. Thus, the functional absorption cross section of Ge-Xian-Mi PSII was increased markedly at NH(4)Cl levels >or=1 mmol L(-1) and the electron transport on the acceptor side of PSII was significantly accelerated by NH(4)Cl addition >or=3 mmol L(-1). Dark respiration of Ge-Xian-Mi was significantly increased by 246% and 384% at 5 and 10 mmol L(-1) NH(4)Cl, respectively. The rapid fluorescence rise kinetics indicated that the oxygen-evolving complex of PSII was the inhibitory site of NH(4)(+).
摘要：
Phytochelatins (PCs) are known to play an essential role in the heavy metal detoxification of some higher plants and fungi by chelating heavy metals. However, three recent papers reported that no PCs could be detected in the hyperaccumulator Sedum alfredii Hance upon cadmium, lead or zinc treatment, respectively. In this paper, PC synthesis was assayed again in the mine population of S. alfredii with the help of reversed phase high-performance liquid chromatography (HPLC), HPLC-mass spectrometry, and HPLC-tandem mass spectrometry. Our data showed that PC formation could be induced in the leaf, stem and root tissues of S. alfredii upon exposure to 400 mu M cadmium, and only in the stem and root when exposed to 700 mu M lead. However, no PCs were found in any part of S. alfredii when it was subjected to exposure to 1600 mu M zinc. (C) 2007 Elsevier Ltd. All rights reserved.
摘要：
H. Cheng, G. Dai, L. Yu, X. Zhong, P. Juneau and B. Qiu. 2008. Influence of CO2 concentrating mechanism on photoinhibition in Synechococcus sp. PCC7942 (Cyanophyceae). Phycologia 47: 588–598. DOI: 10.2216/07-44.1. In this study the effects of inorganic carbon transport in the cyanobacterium Synechococcus sp. PCC7942 on its photoinhibition were investigated. The photosynthetic oxygen evolution of samples under a strong irradiance treatment at 100 µM KHCO3 was much higher than that at 10,000 µM KHCO3. After strong irradiance treatment, the abundance of the sbtA transcript encoding a Na+-dependent transporter was significantly higher under treatment at 100 µM KHCO3 than at 10,000 µM KHCO3. Lincomycin had little effect on the difference of photosystem II (PSII) activity decline under these two treatments, which suggests that CCM activity reduces photodamage but does not boost the rate of PSII repair. The maximal photosynthetic efficiency was decreased significantly during the strong irradiance treatment, and its decrease was enhanced when the external DIC concentration was raised from 100 to 10,000 µM KHCO3. The JIP test showed that there were more active reaction centres under low Ci conditions after high light treatment. Studies on 77-K fluorescence emission spectra showed that the fluorescence peaks F692 nm and F710 nm in 10,000-µM KHCO3 treated samples both decreased after strong irradiance treatment and were significantly smaller than those of 100-µM KHCO3 treated samples. Samples treated with 100 µM KHCO3, compared to 10,000 µM KHCO3 had a higher possibility of transmitting an exciton to a closed reaction centre rather than to an open reaction centre and thus to reduce the overexcitation of the reaction centres. These results indicated that higher external inorganic carbon concentration was associated with more severe photoinhibition under high irradiance and that the operation of CO2 concentrating mechanism might reduce the overexcitation of reaction centres to reduce photodamage.
摘要：
Effects of 111 days enhanced UV-B radiation on leaf pigments, grain quality, photosynthesis and growth were determined in Chinese superhigh-yield hybrid rice (Oryza sativa L.) Liangyoupeijiu (Peiai 64S × 9311). The chlorophyll concentrations of leaves under enhanced UV-B radiation were slightly reduced in the tillering stage, but recovered to levels equal to or above those of control in the later growth stages. Leaves treated with enhanced UV-B radiation for 99 days exhibited higher absorbance in the UV region than controls. Amylose concentration of UV-B treatment was significantly increased by 4.1%. Crude fat concentration, crude protein concentration and vitamin B1 showed no significant difference between control and treatment. The light-saturated photosynthetic activity of UV-B treated leaves normalized on fresh weight or chlorophyll concentration was, respectively, 45.2 and 35.3% higher than controls. Both indoor and field experiments indicated that UV-B treated leaves were more tolerant to photoinhibition, and its Do values tended to be higher than controls during the strong light period of midday. The D1 protein turnover played more important role in UV-B treated leaves against strong irradiance than in control leaves. Little difference was observed in the maximal PSII quantum efficiency of UV-B treated and control leaves during the process of leaf senescence. UV-B radiation reduced diseased grains per panicle and led to a higher seed setting rate. It may have a direct harmful effect on pathogens or reduced susceptibility of UV-B exposed plants to pathogens. Our results suggest that long-term exposure to enhanced UV-B radiation is unlikely to have detrimental effects on the photosynthetic capability of Liangyoupeijiu, and tends to inhibit its growth and biomass.
作者：
Juneau, Philippe;Qiu, Baosheng（邱保胜）;Deblois, Charles P.
期刊：
TOXICOLOGICAL AND ENVIRONMENTAL CHEMISTRY,2007年89(4):609-625 ISSN：0277-2248
通讯作者：
Juneau, P.(juneau.philippe@uqam.ca)
作者机构：
[Juneau, Philippe; Deblois, Charles P.] Department of Biological Sciences–Environmental Toxicology Research Center (TOXEN), Canada Research Chair on Ecotoxicology of Aquatic Microorganisms, University of Québec in Montréal, C.P. 8888, Succursale Centre-Ville, Montreal, Quebec, Canada H3C 3P8;[Qiu, Baosheng] College of Life Sciences, Central China Normal University, Wuhan 430079, Hubei, P. R. China
通讯机构：
[Philippe Juneau] D;Department of Biological Sciences–Environmental Toxicology Research Center (TOXEN), Canada Research Chair on Ecotoxicology of Aquatic Microorganisms, University of Québec in Montréal, C.P. 8888, Succursale Centre-Ville, Montreal, Quebec, Canada H3C 3P8
摘要：
Chlorophyll fluorescence-based methods have been used for many years to study the effect of environmental factors (including herbicides) on plants, and, with the development of very sensitive fluorometers, these methods have become very useful in ecotoxicological studies. This review provides a summary of the research done over the last 10 years concerning the study, by using chlorophyll fluorescence, of the herbicide toxic effects. Although numerous parameters are available, it is striking to notice that the majority of the studies done in the recent years used only a limited number of parameters, thus restraining in some way the interpretation of the obtained results. Furthermore, the use of the maximal photosystem II quantum yield to evaluate toxic effect of herbicides is probably not the best parameter due to its relatively low sensitivity. One should take the advantage of using other parameters such as the operational PSII quantum yield and the non-photochemical quenching since they integrate the entire physiological state of the plant and therefore should be more sensitive. We also recommend the systematic determination of EC50 values in future studies since such determination will permit a more accurate comparison between published reports.
摘要：
B.S. Qiu and Y. Li. 2006. Photosynthetic acclimation and photoprotective mechanism of Haematococcus pluvialis (Chlorophyceae) during the accumulation of secondary carotenoids at elevated irradiation. Phycologia 45: 117–126. DOI: 10.2216/04-99.1 The photosynthetic acclimation of Haematococcus pluvialis Flotow to elevated irradiance and its photoprotective mechanisms were investigated. High light caused a remarkable increment in carotenoid content per cell. Cellular and volumetric chlorophyll contents were significantly increased after four days of high light treatment. Net photosynthesis of high light treated cells was decreased but their dark respiration was increased during the accumulation of secondary carotenoids (SC). The inactivation of reaction centers was observed in high light treated cells, and their normalized complementary area and turnover number were higher than those under low light. The PS II activity of red cells from high light was decreased by 17% compared with green cells from low light but their PS I activity was significantly increased. The K-step could not be observed in the fluorescence transients of red cells, indicating that the oxygen-evolving complex was not affected during SC accumulation. Haematococcus pluvialis could protect itself against strong irradiance through the D1 protein repair cycle and the xanthophyll cycle. The D1 protein repair cycle was the most important protective mechanism in H. pluvialis and its operation could alleviate photoinhibition by 49% in green cells and by 53~55% in red cells. The xanthophyll cycle could contribute to the protection of green cells subjected to strong irradiance but its role was negligible in red cells. Fv /Fo values were decreased in green cells and red cells by 45% and 32~34% respectively after 2.5 hours of photoinhibitory treatment. However, this may not necessarily indicate that the accumulated SC in red cells might play a photoprotective role.
作者机构：
[邱保胜] Cent China Normal Univ, Coll Life Sci, Wuhan 430079, Peoples R China.;Nanjing Univ, Coll Life Sci, Nanjing 210093, Peoples R China.
通讯机构：
[Qiu, BS] C;Cent China Normal Univ, Coll Life Sci, Wuhan 430079, Peoples R China.
关键词：
photoperiod-sensitive genic male-sterile rice;Nongken 58S;JIP test;photoinhibition;reaction center inactivation;D1 protein turnover;xanthophylls cycle
摘要：
The diurnal photosynthesis and photoinhibition in the photoperiod-sensitive genic male-sterile rice (Oryza sativa L.), Nongken 58S (NK58S), were investigated in this paper. From 06:00 to 09:00, no remarkable photoinhibition occurred, and the down-regulation of photosynthesis might be due to the running of xanthophylls cycle. From 10:00 to 12:00, the specific energy flux for dissipation (DIo/RC) and the net rate of reaction centers (RCs) closure (dV/dto) were increased, while the probability of electron transport at the acceptor side (yo) and the density of active RCs (Do) were decreased. These indicated that the photoinhibition of NK58S was exacerbated with the inactivation of PSⅡ RCs. Fluorescence dark relaxation analysis and inhibitor treatment suggested that all of state transition, xanthophyll cycle and inactivation of PSⅡ RCs could contribute to protect NK58S against photodamage. Compared with the inactivation of PSⅡRCs, xanthophyll cycle had an immediate response to high light stress, which functioned mainly in the period of relatively low light intensity. However, the inactivation of PSⅡ RCs played an important role in protecting the remaining active RCs when xanthophyll cycle was saturated.
