This paper reported the diurnal variations of photochemical efficiency of PSII, thermaldissipation rate and other physiology process in the low content chlorophyll mutant rice andits wild type under field conditions, ...This paper reported the diurnal variations of photochemical efficiency of PSII, thermaldissipation rate and other physiology process in the low content chlorophyll mutant rice andits wild type under field conditions, and analyzed the difference of absorbed light distributionbetween the two rice varieties in a day. The results showed that the mutant had poor absorbedlight because of its little light absorption coefficient, but higher electron transportg ratecould partly reduce the disadvantageous effect of deficient absorbed light in mutant. Comparedwith wild-type rice, the mutant had less excess excitation energy and the fraction of absorbedlight allocated to photochemical process was more.展开更多
Biodiesel production from microalgae depends on algal biomass production through autotrophic cultivation,and it has a lot of potential as a feasible alternative source of energy.The lethal and mutagenic effects of eth...Biodiesel production from microalgae depends on algal biomass production through autotrophic cultivation,and it has a lot of potential as a feasible alternative source of energy.The lethal and mutagenic effects of ethyl methanesulphonate(EMS)are investigated in the present study on the organism Chlorella pyrenoidosa for the generation of paler mutants.The C.pyrenoidosa wild-type strain was treated with 0.1,0.2,and 0.5 M EMS doses and the colonies that appeared after 20 days of growth on a solid TAP medium were analyzed,and a total of two mutant colonies with less pigmentation were identified.The CPM1(10.02±0.03 and 3.12±0.04µg/ml)and CPM2(9.55±0.0 and 32.84±0.03µg/ml)mutants had lower chloro-phyll a and b and carotenoids content than wild type.Mutants produced significant biomass(1.34-and 1.31-fold enhanced biomass in CPM1 and CPM2)and lipid content than the wild type.These findings suggest that genetic modification of C.pyrenoidosa has the potential to produce strains with increased biomass productivity and lipid content for biofuel production.展开更多
The green alga Chlamydomonas reinhardtii contains several light-harvesting chlorophyll a/b complexes （LHC）- four major LHCIIs, two minor LHClIs, and nine LHCIs. We characterized three chlorophyll b-less mutants to a...The green alga Chlamydomonas reinhardtii contains several light-harvesting chlorophyll a/b complexes （LHC）- four major LHCIIs, two minor LHClIs, and nine LHCIs. We characterized three chlorophyll b-less mutants to assess the effect of chlorophyll b deficiency on the function, assembly, and stability of these chlorophyll a/b binding proteins. We identified point mutations in two mutants that inactivate the CAO gene responsible for chlorophyll a to chlorophyll b conversion. All LHClIs accumulated to wild-type levels in a CAO mutant but their light-harvesting function for photosystem II was impaired. In contrast, most LHCIs accumulated to wild-type levels in the mutant and their light-harvesting capability for photosystem I remained unaltered. Unexpectedly, LHCl accumulation and the photosystem I functional antenna size increased in the mutant compared with in the wild type when grown in dim light. When the CAO mutation was placed in a yellow-in-the-dark background （yid-BF3）, in which chlorophyll a synthesis remains limited in dim light, accumulation of the major LHClIs and of most LHCls was markedly reduced, indicating that sustained synthesis of chlorophyll a is required to preserve the proteolytic resistance of antenna pro- teins. Indeed, after crossing yid-BF3 with a mutant defective for the thylakoid FtsH protease activity, yid- BF3-ftshl restored wild-type levels of LHCI, which defines LHCI as a new substrate for the FtsH protease.展开更多
基金supported by the National Natural Science Foundation of China(30300217).
文摘This paper reported the diurnal variations of photochemical efficiency of PSII, thermaldissipation rate and other physiology process in the low content chlorophyll mutant rice andits wild type under field conditions, and analyzed the difference of absorbed light distributionbetween the two rice varieties in a day. The results showed that the mutant had poor absorbedlight because of its little light absorption coefficient, but higher electron transportg ratecould partly reduce the disadvantageous effect of deficient absorbed light in mutant. Comparedwith wild-type rice, the mutant had less excess excitation energy and the fraction of absorbedlight allocated to photochemical process was more.
文摘Biodiesel production from microalgae depends on algal biomass production through autotrophic cultivation,and it has a lot of potential as a feasible alternative source of energy.The lethal and mutagenic effects of ethyl methanesulphonate(EMS)are investigated in the present study on the organism Chlorella pyrenoidosa for the generation of paler mutants.The C.pyrenoidosa wild-type strain was treated with 0.1,0.2,and 0.5 M EMS doses and the colonies that appeared after 20 days of growth on a solid TAP medium were analyzed,and a total of two mutant colonies with less pigmentation were identified.The CPM1(10.02±0.03 and 3.12±0.04µg/ml)and CPM2(9.55±0.0 and 32.84±0.03µg/ml)mutants had lower chloro-phyll a and b and carotenoids content than wild type.Mutants produced significant biomass(1.34-and 1.31-fold enhanced biomass in CPM1 and CPM2)and lipid content than the wild type.These findings suggest that genetic modification of C.pyrenoidosa has the potential to produce strains with increased biomass productivity and lipid content for biofuel production.
文摘The green alga Chlamydomonas reinhardtii contains several light-harvesting chlorophyll a/b complexes （LHC）- four major LHCIIs, two minor LHClIs, and nine LHCIs. We characterized three chlorophyll b-less mutants to assess the effect of chlorophyll b deficiency on the function, assembly, and stability of these chlorophyll a/b binding proteins. We identified point mutations in two mutants that inactivate the CAO gene responsible for chlorophyll a to chlorophyll b conversion. All LHClIs accumulated to wild-type levels in a CAO mutant but their light-harvesting function for photosystem II was impaired. In contrast, most LHCIs accumulated to wild-type levels in the mutant and their light-harvesting capability for photosystem I remained unaltered. Unexpectedly, LHCl accumulation and the photosystem I functional antenna size increased in the mutant compared with in the wild type when grown in dim light. When the CAO mutation was placed in a yellow-in-the-dark background （yid-BF3）, in which chlorophyll a synthesis remains limited in dim light, accumulation of the major LHClIs and of most LHCls was markedly reduced, indicating that sustained synthesis of chlorophyll a is required to preserve the proteolytic resistance of antenna pro- teins. Indeed, after crossing yid-BF3 with a mutant defective for the thylakoid FtsH protease activity, yid- BF3-ftshl restored wild-type levels of LHCI, which defines LHCI as a new substrate for the FtsH protease.
