The structures of mature embryo sacs in 13 genetic stock lines of autotetraploid rice (Oryza sativa L.), including indica, japonica and javanica, were studied by using the whole-mount stain-clearing laser scanning con...The structures of mature embryo sacs in 13 genetic stock lines of autotetraploid rice (Oryza sativa L.), including indica, japonica and javanica, were studied by using the whole-mount stain-clearing laser scanning confocal microscopy (WCLSM). Among the 13 autotetraploid rice, the majority of ovaries possess normal polygonum-type embryo sacs, while a few ovaries were characterized by abnormal embryo sacs. The abnormalities of embryo sacs could be classified into six categories, i. e. no female germ unit, abnormal polar nuclei, embryo sac degeneration, no egg apparatus, small embryo sac and ‘double set’ of embryo sacs. The frequency of abnormal embryo sac in japonica (26.6%) was higher than that in indica (19.34%). In addition, the major abnormalities in each autotetraploid line varied, suggesting that the abnormalities may be related to the genotypes of the varieties.展开更多
By using the laser scanning confocal microscope and plastic (Leica 7022 historesin embedding kit) semi-thin sectioningtechnique, comparative studies on the development of endosperm were carried out between autotetrapl...By using the laser scanning confocal microscope and plastic (Leica 7022 historesin embedding kit) semi-thin sectioningtechnique, comparative studies on the development of endosperm were carried out between autotetraploid and diploid rices. Aboutone third of the ovaries in the autotetraploid showed normal endosperm development as those in the diploid. In these ovaries, one ofthe polar nuclei would fuse with the sperm nucleus, and the primary endosperm nucleus formed and underwent the first division in 4hours after pollination; the anticlinal wall began to grow centripetally between the free nuclei starting from the wall ingrowths of theembryo sac near the micropylar end, and some of the phragmoplasts formed transformed into periclinal walls. In addition, some of thecell wall situated in the middle of the endosperm appeared to originate from phragmoplasts, whereas others seemed to developrandomly without the obvious formation of phragmoplasts. Cellulose began to accumulate in the wall of aleurone cell layer at 6 daysafter pollination. The cellulose wall of the cells of the aleurone cell layer appeared to have completely formed within 7 to 8 days afterpollination. On the other hand, about two thirds of the ovaries in the autotetraploid showed abnormality in endosperm developmentwith various types, such as non-fertilization, abnormal fertilization, endosperm development-delay and non-synchronization in thedevelopment of cellulose wall of cells of the aleurone layer. These abnormalities usually resulted in decreased seed setting inautotetraploid rice.展开更多
In the present study autotetraploid rice IR36-4X was treated by an ion implantationtechnique with nitrogen ion beams.A polyembryonic mutant (named IR36-Shuang) was identifiedin the M_2 generation.The mutant line and i...In the present study autotetraploid rice IR36-4X was treated by an ion implantationtechnique with nitrogen ion beams.A polyembryonic mutant (named IR36-Shuang) was identifiedin the M_2 generation.The mutant line and its offspring were systematically investigated in regardto their major agronomic properties and the rate of polyembryonic seedling in the M_3-M_6 gener-ation.The abnormal phenomena in the embryo sac development and the cytological mechanismof the initiation of additional embryo in IR36-Shuang were observed by Laser Scanning Confo-cal Microscopy.The results were as follows.1) The plant height,the panicle length and 1000grain weight of IR36-Shuang were lower than that of its control by 35.41%,5.08% and 15.72%respectively,Moreover,the setting percentage decreased 12.39% compared with that in normalIR36-4X plants.2) The polyembryonic trait of IR36-Shuang was genetically stable and the fre-quency of the polyembryonic seedlings in the IR36-Shuang line was also relatively stable.3) Therate of abnormal embryo sacs in IR36-Shuang was significantly higher than that in the controlIR36-4X.4) The additional embryo in IR36-Shuang might arise from the double set of embryosacs in a single ovary,antipodal cells or endosperm cells.These results suggest that IR36-Shuangis a polyembryonic mutant and a new apomixis rice line induced by low energy ion implantation.The prospects for the application in production of the IR36-Shuang line are also discussed.Thepresent study may provide a basis for future investigations of apomixis rice breeding via the ionimplantation biotechnology.展开更多
Calluses of two autotetraploid rice(DPR(4) and Zijing(4)) were implanted with 30 KeV N+beams at doses ranging from1.0×1015to 9.0×1015ions cm-2.The differentiation rates of calluses,the concentration of malon...Calluses of two autotetraploid rice(DPR(4) and Zijing(4)) were implanted with 30 KeV N+beams at doses ranging from1.0×1015to 9.0×1015ions cm-2.The differentiation rates of calluses,the concentration of malondialdehyde(MDA),the activities of superoxide dismutase(SOD),catalase(CAT) and peroxidase(POD),and the change of esterase(EST) spectrum were measured and analyzed on the calluses stage.The results showed that differentiation rates of calluses under 3.0×1015ions cm-2((46.12±2.01)%) were higher than the other treatment groups in DPR(4),and those of Zijing(4) were similar under the doses of 1.0×1015,3.0×1015and 5.0×1015ions cm-2((40.55±2.74),(37.77±3.04) and(34.56±2.65)%) and were higher than that of 7.0×1015and 9.0×1015ions cm-2.When the doses were 3.0×1015and 5.0×1015ions cm-2,the activities of SOD,POD and CAT were notably enhanced,and the accumulation of MDA content was markedly alleviated in the implanted calluses of two materials,as well as the activity of EST was increased by the additional isforms DPR(4).Whereas the anti-oxidative systems and enzymes spectrum of EST were destroyed seriously,the accumulation of MDA was significantly aggravated,also the differentiation rate of calluses reduced sharply and almost closed to zero when the implantation doses were 7.0×1015and 9.0×1015ions cm-2.It suggested that the proper dose of ion implantation effectively maintained the normal membrane structure and metabolism,and it would be also a feasible approach for autotetraploid rice to improve its genetic characteristics at calluses stage.Additionally,the differences of the radiation resistance between DPR(4) and Zijing(4) could be related to the different genotypes.展开更多
The effect of Ar^+ beam implantation and maize genome DNA on autotetraploid riceis studied.Better mutation types and higher mutation rates were discovered in M2 of T3 with ionimplantation and immersion in maize genome...The effect of Ar^+ beam implantation and maize genome DNA on autotetraploid riceis studied.Better mutation types and higher mutation rates were discovered in M2 of T3 with ionimplantation and immersion in maize genome DNA.In the five agronomic categories investigated,the mutation rate of the seed setting rate was 9.1%,and the total mutation rate was 14.8% in theT3.However,the total mutation rate was 2.1% with the treatment of only ion implantation and1.3% with the treatment of only immersion in maize genome DNA.Mutant FA36(4) was discoveredin M1 with ion beam implantation and immersion in maize genome DNA.Its RuBPCase activity,PEPCase activity and seed setting rate were 32%,153%,and 36.79%,respectively,higher thanits parent IR36(4).Rapid analysis of polymorphicDNA (RAPD) analysis of three M2 plants ofFA36(4) (FM1,FM2,FM3) and two controls (purple maize and IR36(4)) were also conductedwith 40 random primers.S_5-3 was RAPD fragment amplified with a template of purple maize,FM2 and FM3 genome DNA using primer S_5.There was no S_5-3 in the RAPD pattern of IR36(4)or FM1.展开更多
The process of double fertilization and the characters of embryo and endosperm development in an autotetraploid polyembryonic mutant rice IR36-Shuang were studied with a laser scanning confocal microscopy.Some abnorma...The process of double fertilization and the characters of embryo and endosperm development in an autotetraploid polyembryonic mutant rice IR36-Shuang were studied with a laser scanning confocal microscopy.Some abnormalities including degenerated ovary,abortive embryo sac,single fertilization,double-ovule and double-embryo and so on.were found during double fertilization and embryo development in IR36-Shuang.The rate of the abnormalities was 46.67%in IR36-Shuang,significantly higher than that in the control,an autotetraploid rice line IR36-4X(33.00%) .Cytological and embryonic evidences were provided for seed setting decline and the initiation of additional embryo in IR36-Shuang.展开更多
基金supported by the National Natural Science Foundations of China(Grant No.30270814)the Teaching and Research Award Program for 0utstanding Young Teachers in Higher Education Institutions of M0E,P.R.China.
文摘The structures of mature embryo sacs in 13 genetic stock lines of autotetraploid rice (Oryza sativa L.), including indica, japonica and javanica, were studied by using the whole-mount stain-clearing laser scanning confocal microscopy (WCLSM). Among the 13 autotetraploid rice, the majority of ovaries possess normal polygonum-type embryo sacs, while a few ovaries were characterized by abnormal embryo sacs. The abnormalities of embryo sacs could be classified into six categories, i. e. no female germ unit, abnormal polar nuclei, embryo sac degeneration, no egg apparatus, small embryo sac and ‘double set’ of embryo sacs. The frequency of abnormal embryo sac in japonica (26.6%) was higher than that in indica (19.34%). In addition, the major abnormalities in each autotetraploid line varied, suggesting that the abnormalities may be related to the genotypes of the varieties.
基金supported by the National Natural Science Foundation of China(30270814)the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE,R R.Chinathe Group Project of Natural Science Foundation of Guangdong Province(200023).
文摘By using the laser scanning confocal microscope and plastic (Leica 7022 historesin embedding kit) semi-thin sectioningtechnique, comparative studies on the development of endosperm were carried out between autotetraploid and diploid rices. Aboutone third of the ovaries in the autotetraploid showed normal endosperm development as those in the diploid. In these ovaries, one ofthe polar nuclei would fuse with the sperm nucleus, and the primary endosperm nucleus formed and underwent the first division in 4hours after pollination; the anticlinal wall began to grow centripetally between the free nuclei starting from the wall ingrowths of theembryo sac near the micropylar end, and some of the phragmoplasts formed transformed into periclinal walls. In addition, some of thecell wall situated in the middle of the endosperm appeared to originate from phragmoplasts, whereas others seemed to developrandomly without the obvious formation of phragmoplasts. Cellulose began to accumulate in the wall of aleurone cell layer at 6 daysafter pollination. The cellulose wall of the cells of the aleurone cell layer appeared to have completely formed within 7 to 8 days afterpollination. On the other hand, about two thirds of the ovaries in the autotetraploid showed abnormality in endosperm developmentwith various types, such as non-fertilization, abnormal fertilization, endosperm development-delay and non-synchronization in thedevelopment of cellulose wall of cells of the aleurone layer. These abnormalities usually resulted in decreased seed setting inautotetraploid rice.
基金supported by National Key Projects of China(No.2001BA302B)
文摘In the present study autotetraploid rice IR36-4X was treated by an ion implantationtechnique with nitrogen ion beams.A polyembryonic mutant (named IR36-Shuang) was identifiedin the M_2 generation.The mutant line and its offspring were systematically investigated in regardto their major agronomic properties and the rate of polyembryonic seedling in the M_3-M_6 gener-ation.The abnormal phenomena in the embryo sac development and the cytological mechanismof the initiation of additional embryo in IR36-Shuang were observed by Laser Scanning Confo-cal Microscopy.The results were as follows.1) The plant height,the panicle length and 1000grain weight of IR36-Shuang were lower than that of its control by 35.41%,5.08% and 15.72%respectively,Moreover,the setting percentage decreased 12.39% compared with that in normalIR36-4X plants.2) The polyembryonic trait of IR36-Shuang was genetically stable and the fre-quency of the polyembryonic seedlings in the IR36-Shuang line was also relatively stable.3) Therate of abnormal embryo sacs in IR36-Shuang was significantly higher than that in the controlIR36-4X.4) The additional embryo in IR36-Shuang might arise from the double set of embryosacs in a single ovary,antipodal cells or endosperm cells.These results suggest that IR36-Shuangis a polyembryonic mutant and a new apomixis rice line induced by low energy ion implantation.The prospects for the application in production of the IR36-Shuang line are also discussed.Thepresent study may provide a basis for future investigations of apomixis rice breeding via the ionimplantation biotechnology.
基金financially supported by the National Natural Science Foundation of China(10505018)the Natural Science Foundation of Henan ProvinceChina(091100110401)
文摘Calluses of two autotetraploid rice(DPR(4) and Zijing(4)) were implanted with 30 KeV N+beams at doses ranging from1.0×1015to 9.0×1015ions cm-2.The differentiation rates of calluses,the concentration of malondialdehyde(MDA),the activities of superoxide dismutase(SOD),catalase(CAT) and peroxidase(POD),and the change of esterase(EST) spectrum were measured and analyzed on the calluses stage.The results showed that differentiation rates of calluses under 3.0×1015ions cm-2((46.12±2.01)%) were higher than the other treatment groups in DPR(4),and those of Zijing(4) were similar under the doses of 1.0×1015,3.0×1015and 5.0×1015ions cm-2((40.55±2.74),(37.77±3.04) and(34.56±2.65)%) and were higher than that of 7.0×1015and 9.0×1015ions cm-2.When the doses were 3.0×1015and 5.0×1015ions cm-2,the activities of SOD,POD and CAT were notably enhanced,and the accumulation of MDA content was markedly alleviated in the implanted calluses of two materials,as well as the activity of EST was increased by the additional isforms DPR(4).Whereas the anti-oxidative systems and enzymes spectrum of EST were destroyed seriously,the accumulation of MDA was significantly aggravated,also the differentiation rate of calluses reduced sharply and almost closed to zero when the implantation doses were 7.0×1015and 9.0×1015ions cm-2.It suggested that the proper dose of ion implantation effectively maintained the normal membrane structure and metabolism,and it would be also a feasible approach for autotetraploid rice to improve its genetic characteristics at calluses stage.Additionally,the differences of the radiation resistance between DPR(4) and Zijing(4) could be related to the different genotypes.
基金the National Key Program of China(2001BA302B03)Doctoral Startup Foundation of Huuan Science and Technology University of China(E54141)Educational Department Foundation of Hunan Province of China
文摘The effect of Ar^+ beam implantation and maize genome DNA on autotetraploid riceis studied.Better mutation types and higher mutation rates were discovered in M2 of T3 with ionimplantation and immersion in maize genome DNA.In the five agronomic categories investigated,the mutation rate of the seed setting rate was 9.1%,and the total mutation rate was 14.8% in theT3.However,the total mutation rate was 2.1% with the treatment of only ion implantation and1.3% with the treatment of only immersion in maize genome DNA.Mutant FA36(4) was discoveredin M1 with ion beam implantation and immersion in maize genome DNA.Its RuBPCase activity,PEPCase activity and seed setting rate were 32%,153%,and 36.79%,respectively,higher thanits parent IR36(4).Rapid analysis of polymorphicDNA (RAPD) analysis of three M2 plants ofFA36(4) (FM1,FM2,FM3) and two controls (purple maize and IR36(4)) were also conductedwith 40 random primers.S_5-3 was RAPD fragment amplified with a template of purple maize,FM2 and FM3 genome DNA using primer S_5.There was no S_5-3 in the RAPD pattern of IR36(4)or FM1.
基金supported by the National Science & Technology Pillar Program of China in the Tenth Five-Year Plan Period(Grant No.2001BA302B)the Education Department of Henan Province, China(Grant No.2008A208019)
文摘The process of double fertilization and the characters of embryo and endosperm development in an autotetraploid polyembryonic mutant rice IR36-Shuang were studied with a laser scanning confocal microscopy.Some abnormalities including degenerated ovary,abortive embryo sac,single fertilization,double-ovule and double-embryo and so on.were found during double fertilization and embryo development in IR36-Shuang.The rate of the abnormalities was 46.67%in IR36-Shuang,significantly higher than that in the control,an autotetraploid rice line IR36-4X(33.00%) .Cytological and embryonic evidences were provided for seed setting decline and the initiation of additional embryo in IR36-Shuang.