Objective： To evaluate the possible photoprotection mechanisms of cyclic and linear electron flux （CEF and LEF） under specific high temperature and high light （HH） stress. Methods： Six-leaf-stage tomato seedlin...Objective： To evaluate the possible photoprotection mechanisms of cyclic and linear electron flux （CEF and LEF） under specific high temperature and high light （HH） stress. Methods： Six-leaf-stage tomato seedlings （＂Liaoyuanduoli＂, n=160） were divided into four parts： Part 1, served as control under 25 ℃, 500 pmol/（m2-s）; Part 2, spayed with distilled water （H20） under 35 ℃, 1000 pmol/（m2.s） （HH）; Part 3, spayed with 100 μmol/L diuron （DCMU, CEF inhibitor） under HH; Part 4, spayed with 60 pmol/L methyl viologen （MV, LEF inhibitor） under HH. Energy conversion, photosystem I （PSI）, and PSII activity, and trans-thylakoid membrane proton motive force were monitored during the treatment of 5 d and of the recovering 10 d. Results： HH decreased photochemical reaction dissipation （P） and the maximal photochemical efficiency of PSII （Fv/Fm）, and increased the excitation energy distribution coefficient of PSII （,8）; DCMU and MV aggravated the partition imbalance of the excitation energy （y） and the photoinhibition degree. With prolonged DCMU treatment time, electron transport rate and quantum efficiency of PSI （ETR= and Y1） significantly decreased whereas acceptor and donor side limitation of PSI （YNA and YND） increased. MV led to a significant decline and accession of yield of regulated and non-regulated energy Y NPQ and YNO, respectively. Membrane integrity and ATPase activity were reduced by HH stress, and DCMU and MV enhanced inhibitory actions. Conclusions： The protective effects of CEF and LEF were mediated to a certain degree by meliorations in energy absorption and distribution as well as by maintenance of thylakoid membrane integrity and ATPase activity.展开更多
The recently discovered nitrate ore field in the Turpan-Hami Basin of western China represents an estimated resource of 2.5 billion tons, and is comparable in scale to the Atacama Desert super-scale nitrate deposit in...The recently discovered nitrate ore field in the Turpan-Hami Basin of western China represents an estimated resource of 2.5 billion tons, and is comparable in scale to the Atacama Desert super-scale nitrate deposit in Chile. The research on this area is rarely carried out, and the origin of the deposits remains uncertain. In this study, new methods were used to systematically analyze N and O isotopes in nitrate minerals collected from the Kumutage, Xiaocaohu, Wuzongbulak, Dawadi, Tuyugou, and Shaer ore deposits in the Turpan-Hami Basin. The data showed that the δ15NAir value ranges from 0.7‰ to 27.6‰, but mostly between 2‰ and 6‰, which was similar to atmospheric NO3-. The 18O was highly enriched with δ18OV-SMOW varying from 30.2‰ to 46.7‰. This differs from levels in deposits derived from microbial nitrogen fixation, but is similar to those in atmospheric nitrates. N and O isotopes data indicated that nitrate deposits in Turpan-Hami Basin must be the result of deposition of atmospheric nitrate particles. Although atmospheric nitrate particles are common, the nitrate deposits could form only under the condition of long-term extreme drought climate and very limited biological activity. This paper summarized the ore-forming mechanism of different types nitrate deposits based on their geological setting.展开更多
基金Project supported by the China Agriculture Research System(No.CARS-25)the National Natural Science Foundation of China(No.31301813)the National Key Technologies R&D Program of China(No.2015103003)
文摘Objective： To evaluate the possible photoprotection mechanisms of cyclic and linear electron flux （CEF and LEF） under specific high temperature and high light （HH） stress. Methods： Six-leaf-stage tomato seedlings （＂Liaoyuanduoli＂, n=160） were divided into four parts： Part 1, served as control under 25 ℃, 500 pmol/（m2-s）; Part 2, spayed with distilled water （H20） under 35 ℃, 1000 pmol/（m2.s） （HH）; Part 3, spayed with 100 μmol/L diuron （DCMU, CEF inhibitor） under HH; Part 4, spayed with 60 pmol/L methyl viologen （MV, LEF inhibitor） under HH. Energy conversion, photosystem I （PSI）, and PSII activity, and trans-thylakoid membrane proton motive force were monitored during the treatment of 5 d and of the recovering 10 d. Results： HH decreased photochemical reaction dissipation （P） and the maximal photochemical efficiency of PSII （Fv/Fm）, and increased the excitation energy distribution coefficient of PSII （,8）; DCMU and MV aggravated the partition imbalance of the excitation energy （y） and the photoinhibition degree. With prolonged DCMU treatment time, electron transport rate and quantum efficiency of PSI （ETR= and Y1） significantly decreased whereas acceptor and donor side limitation of PSI （YNA and YND） increased. MV led to a significant decline and accession of yield of regulated and non-regulated energy Y NPQ and YNO, respectively. Membrane integrity and ATPase activity were reduced by HH stress, and DCMU and MV enhanced inhibitory actions. Conclusions： The protective effects of CEF and LEF were mediated to a certain degree by meliorations in energy absorption and distribution as well as by maintenance of thylakoid membrane integrity and ATPase activity.
基金supported by Basic Scientific Research Operation Cost of State-Leveled Public Welfare Scientific Research Courtyard (Grant No. K0926)National Natural Science Foundation of China (Grant Nos. 40543013, 40873003)Key Laboratory of Isotope Geology, Ministry of Land and Resources
文摘The recently discovered nitrate ore field in the Turpan-Hami Basin of western China represents an estimated resource of 2.5 billion tons, and is comparable in scale to the Atacama Desert super-scale nitrate deposit in Chile. The research on this area is rarely carried out, and the origin of the deposits remains uncertain. In this study, new methods were used to systematically analyze N and O isotopes in nitrate minerals collected from the Kumutage, Xiaocaohu, Wuzongbulak, Dawadi, Tuyugou, and Shaer ore deposits in the Turpan-Hami Basin. The data showed that the δ15NAir value ranges from 0.7‰ to 27.6‰, but mostly between 2‰ and 6‰, which was similar to atmospheric NO3-. The 18O was highly enriched with δ18OV-SMOW varying from 30.2‰ to 46.7‰. This differs from levels in deposits derived from microbial nitrogen fixation, but is similar to those in atmospheric nitrates. N and O isotopes data indicated that nitrate deposits in Turpan-Hami Basin must be the result of deposition of atmospheric nitrate particles. Although atmospheric nitrate particles are common, the nitrate deposits could form only under the condition of long-term extreme drought climate and very limited biological activity. This paper summarized the ore-forming mechanism of different types nitrate deposits based on their geological setting.
