期刊文献+
共找到21篇文章
< 1 2 >
每页显示 20 50 100
NATO's Missiles Shattered the Bridge of Cultural Exchange
1
《China & The World Cultural Exchange》 1999年第4期11-14,共4页
关键词 NATO’s Missiles shattered the Bridge of Cultural Exchange
下载PDF
Beijing Review Observer:Japan’s Incredible Calmness and Strength OVERCOMING A CATACLYSM The Japanese begin to put their shattered economy back on track
2
作者 AYAKO KATSUMATA 《Beijing Review》 2011年第13期10-17,共8页
Earthquake,tsunami,nuclear plantb reakdown.Each is a major catast rophe.But Japan has been hit by all of them.Homelessness,economic losses,release of radiation.Each is a huge challenge.Now Japan must face all three.Ho... Earthquake,tsunami,nuclear plantb reakdown.Each is a major catast rophe.But Japan has been hit by all of them.Homelessness,economic losses,release of radiation.Each is a huge challenge.Now Japan must face all three.How will Japan respond to the domino-like disaster 展开更多
关键词 In Beijing Review Observer:Japan’s Incredible Calmness and Strength OVERCOMING A CATACLYSM The Japanese begin to put their shattered economy back on track www
原文传递
Wheel/rail-force–based maintenance interval extension of the C80 series wagon
3
作者 Qi Xiao Weidong Yu +1 位作者 Guangrong Tian Fangxuan Li 《Railway Sciences》 2023年第4期514-524,共11页
Purpose–This study aims to introduce the achievements and benefits of applying wheel/rail-force–based maintenance interval extension of the C80 series wagon in China.Design/methodology/approach–Chinese wagons’exis... Purpose–This study aims to introduce the achievements and benefits of applying wheel/rail-force–based maintenance interval extension of the C80 series wagon in China.Design/methodology/approach–Chinese wagons’existing maintenance strategy had left a certain safety margin for the characteristics of widely running range,unstable service environment and submission to transportation organization requirements.To reduce maintenance costs,China railway(CR)has attempted to extend the maintenance interval since 2020.The maintenance cycle of C80 series heavy haul wagons is extended by three months(no stable routing)or 50,000 km(regular routing).However,in the meantime,the alarming rate of the running state,a key index to reflect the severe degree of hunting stability,by the train performance detection system(TPDS)for the C80 series heavy haul wagons has increased significantly.Findings–The present paper addresses a big data statistical way to evaluate the risk of allowing the C80 series heavy haul wagons to remain in operation longer than stipulated by the maintenance interval initial set.Through the maintenance and wayside-detectordata,whichis divided intothreestages,the extension period(three months),the current maintenance period and the previous maintenance period,this method reveals the alarming rate of hunting was correlated with maintenance interval.The maintainability of wagons will be achieved by utilizing wagon performance degradation modeling with the state of the wheelset and the often-contact side bearing.This paper also proposes a statistical model to return to the average safety level of the previous maintenance period’s baseline through correct alarming thresholds for unplanned corrective maintenance.Originality/value–The paper proposes an approach to reduce safety risk due to maintenance interval extension by effective maintenance program.The results are expected to help the railway company make the optimal solution to balance safety and the economy. 展开更多
关键词 Full-continuous wheel–rail force measurement TPDS shattered rim HUNTING C80 series heavy haul wagons Maintainability
下载PDF
Phenotypical and gene co-expression network analyses of seed shattering in divergent sorghum(Sorghum spp.)
4
作者 Xin Xiao Mengjiao Zhu +6 位作者 Yishan Liu Jingru Zheng Yiping Cui Candong Xiong Jiangjiang Liu Jun Chen Hongwei Cai 《The Crop Journal》 SCIE CSCD 2023年第2期478-489,共12页
Sorghum[Sorghum bicolor(L.)Moench],a multipurpose C4 crop,is also a model species of the Poaceae family for plant research.During the process of domestication,the modification of seed dispersal mode is considered a ke... Sorghum[Sorghum bicolor(L.)Moench],a multipurpose C4 crop,is also a model species of the Poaceae family for plant research.During the process of domestication,the modification of seed dispersal mode is considered a key event,as the loss of seed shattering caused a significant increase in yield.In order to understand the seed shattering process in sorghum,we further studied eight previously identified divergent sorghum germplasm with different shattering degrees.We described their phenotypes in great detail,analyzed the histology of abscission zone,and conducted a gene co-expression analysis.We observed that the abscission layer of the most strong-shattering varieties began to differentiate before the 5-10 cm panicles development stage and was completely formed at flag leaf unfolding.The protective cells on the pedicels were also fully lignified by flowering.Through the weighted gene correlation network analysis(WGCNA),we mined for candidate genes involved in the abscission process at the heading stage.We found that these genes were mainly associated with such biological processes as hormone signal transmission(SORBI_3003G361300,SORBI_3006G216500,SORBI_3009G027800,SORBI_3007G077200),cell wall modification and degradation(SORBI_3002G205500,SORBI_3004G013800,SORBI_3010G022400,SORBI_3003G251800,SORBI_3003G254700,SORBI_3003G410800,SORBI_3009G162700,SORBI_3001G406700,SORBI_3004G042700,SORBI_3004G244600,SORBI_3001G099100),and lignin synthesis(SORBI_3004G220700,SORBI_3004G062500,SORBI_3010G214900,SORBI_3009G181800).Our study has provided candidate genes required for shedding for further study.We believe that function characterization of these genes may provide insight into our understanding of seed shattering process. 展开更多
关键词 Divergent sorghum Seed shattering Abscission zone WGCNA
下载PDF
After Effects中Shatter(碎片)滤镜的使用方法与实践 被引量:2
5
作者 周勉 《软件》 2013年第2期146-147,170,共3页
在影视作品包装中,破碎效果这个特效非常重要,也是非常常用。制作爆炸的软件有很多,本文利用在After Effects中自带滤镜Shatter制作出相对真实的爆炸效果,来了解Shatter的基本功能。
关键词 AFTEREFFECTS SHATTER 爆炸 立体文字
下载PDF
Combining Ability and Breeding Potential of Rapeseed Elite Lines for Pod Shatter Resistance 被引量:4
6
作者 LIU Jia MEI De-sheng +5 位作者 LI Yun-chang CUI Jia-cheng WANG Hui PENG Peng-fei FU Li HU Qiong 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2013年第3期552-555,共4页
Pod shatter resistance of rapeseed is of great importance for modem farming practice. In order to determine the combining ability of elite inbred lines and the breeding potential of rapeseed hybrids in terms of pod sh... Pod shatter resistance of rapeseed is of great importance for modem farming practice. In order to determine the combining ability of elite inbred lines and the breeding potential of rapeseed hybrids in terms of pod shatter resistance, analysis of a 6×6 incomplete diallel cross was conducted at two locations. Results showed that a significant variation existed among breeding lines and their F1 hybrids for pod shatter resistant index (SRI), pod length and width. Pod shatter resistance was significantly positively correlated with pod length. The general combining ability (GCA) effects (GCA=l.58) played a more important role than specific combining ability (SCA) effects (SCA=0.20) for pod shatter trait. The elite lines R1, 1019B and 1055B displayed significant positive GCA effects for pod shatter resistance. Four crosses (1019B×R1, 1015B×R1, 6098B×R1, and 8908B×R1) with high mean performance and positive SCA effects were recommended for developing new hybrids for mechanical harvest in the middle reaches of the Yangtze River. 展开更多
关键词 RAPESEED pod shatter resistance elite lines breeding potential
下载PDF
Effects of paclobutrazol on biomass production in relation to resistance to lodging and pod shattering in Brassica napus L. 被引量:2
7
作者 KUAI Jie LI Xiao-yong +1 位作者 YANG Yang ZHOU Guang-sheng 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2017年第11期2470-2481,共12页
Paclobutrazol was sprayed at 0, 150, and 300 mg L-1 during the closed canopy stage and the early bud stage with two high-yielding cultivars of rapeseed, Yangguang 2009 and Fengyou 520. The impact of paclobutrazol on t... Paclobutrazol was sprayed at 0, 150, and 300 mg L-1 during the closed canopy stage and the early bud stage with two high-yielding cultivars of rapeseed, Yangguang 2009 and Fengyou 520. The impact of paclobutrazol on the accumulation and distribution of biomass and its relationship with yield, resistance to lodging and pod shattering were determined. All the treatments increased the resistance as well as yield. The maximum yield was obtained when paclobutrazol was applied during the closed canopy stage at 150 mg L-1. The plant's resistance to both lodging and pod shattering was the maximum when paclobutrazol was applied during the early bud stage at 300 mg L-1. Paclobutrazol also delayed senescence, with the higher concentration or later spraying leading to more obvious effects; improved the net assimilation rate before the early bud stage; and promoted the relative growth rate of the main growth organ at each stage of growth and maximized the rate and quantities of biomass accumulation. However, at the higher concentration and later spraying, the increments were smaller. The spraying also increased the rates of biomass allocation to roots, leaves, and pods, but the rate of allocation to stems decreased as the plants grew shorter. The higher allocation to roots and the lower allocation to stems favoured resistance to both lodging and pod shattering whereas higher allocation to leaves and pods favoured yield. The higher concentration or late spraying led to excessive biomass being allocated to roots, which decreased leaf biomass during the bud stage, leading to greater resistance but lower yields. 展开更多
关键词 RAPESEED PACLOBUTRAZOL biomass yield resistance to lodging and shattering
下载PDF
A lignified-layer bridge controlled by a single recessive gene is associated with high pod-shatter resistance in Brassica napus L. 被引量:2
8
作者 Wen Chu Jia Liu +8 位作者 Hongtao Cheng Chao Li Li Fu Wenxiang Wang Hui Wang Mengyu Hao Desheng Mei Kede Liu Qiong Hu 《The Crop Journal》 SCIE CSCD 2022年第3期638-646,共9页
Pod shattering causes severe yield loss in rapeseed(Brassica napus L.)under modern agricultural practice.Identification of highly shatter-resistant germplasm is desirable for the development of rapeseed cultivars for ... Pod shattering causes severe yield loss in rapeseed(Brassica napus L.)under modern agricultural practice.Identification of highly shatter-resistant germplasm is desirable for the development of rapeseed cultivars for mechanical harvesting.In the present study,an elite line OR88 with strong shatter resistance and a lignified-layer bridge(LLB)structure was identified.The LLB structure was unique to OR88 and co-segregated with high pod-shatter resistance.The LLB structure is differentiated at stage 12 of gynoecium development without any gynoecium defects.Genetic analysis showed that LLB is controlled by a single recessive gene.By BSA-Seq and map-based cloning,the resistance gene location was delimited to a0.688 Mb region on chromosome C09.Transcriptome analysis suggested Bn TCP8.C09 as the gene responsible for LLB.The expression of Bn TCP.C09 was strongly downregulated in OR88,suppressing cell proliferation in the pod valve margin.KASP markers linked to the candidate gene were developed.This pod shatter-resistant line could be used in rapeseed breeding programs by direct transfer of the gene with the assistance of the DNA markers. 展开更多
关键词 Pod shatter Lignified-layer bridge BSA-Seq KASP marker RAPESEED
下载PDF
Effects of Planting and Maturity Dates on Shattering Patterns under Early Soybean Production System 被引量:2
9
作者 Lingxiao Zhang Nacer Bellaloui 《American Journal of Plant Sciences》 2012年第1期119-124,共6页
Seed shattering is a common problem in early soybean production system (ESPS) in the Midsouth, which mainly uses maturity group (MG) IV soybeans. Many studies have been conducted on the genetics of soybean shattering ... Seed shattering is a common problem in early soybean production system (ESPS) in the Midsouth, which mainly uses maturity group (MG) IV soybeans. Many studies have been conducted on the genetics of soybean shattering resistance for individual varieties;however, information on the physiology of soybean shattering pattern under specific environmental conditions, which is often critical to soybean growers, is very limited. Field experiments were conducted at Stoneville MS from 2007 to 2009 to investigate the shattering patterns of 80-132 MG IV soybean varieties each year. Results from 2007 and 2008 indicated that, when April-planted MG IV soybeans matured in mid- to late August, pods of most soybean varieties did not shatter within the first three weeks after maturity (WAM) and there was no significant shattering effect on final yields. However, differences in pod shattering among the varieties became apparent in the fourth WAM. Late-planted MG IV soybeans, which matured in early September, had a low shattering rate and could hold seeds up to 6 WAM before reaching a critical shattering point. Most soybean varieties planted in April 2009 did not show significant pod shattering by the end of the fourth WAM. The critical point of shattering was not reached until 6 - 7 WAM. Relatively lower temperatures and abundant rainfall during the late growing season in 2009 may be the main reasons causing delayed shattering in April-planted MG IV soybeans. Results from the May-planting of 2007 and the April-planting of 2009 indicated that soybeans maturing after September have much less problematic shattering. Different weather patterns, especially temperature and rainfall in each year could be essential factors affecting seed shattering patterns. 展开更多
关键词 SOYBEAN SHATTERING MATURITY Group PLANTING DATE Weather
下载PDF
Formation Mechanism and Occurrence Law of Pod Shattering in Soybean:A Review 被引量:1
10
作者 Jinfeng Liu Yuzhe Zhang +6 位作者 Yushi Jiang Hongji Sun Ruijie Duan Jing Qu Dan Yao Siyan Liu Shuyan Guan 《Phyton-International Journal of Experimental Botany》 SCIE 2022年第7期1327-1340,共14页
Seed shattering refers to the phenomenon in which the pods split along the abdominal and back sutures before the crop is received,so that the seeds are spread.Seed shattering is vital to the reproduction of their offs... Seed shattering refers to the phenomenon in which the pods split along the abdominal and back sutures before the crop is received,so that the seeds are spread.Seed shattering is vital to the reproduction of their offspring in wild plants,but it is also the main cause of crop yield loss reason.Pod-explosion resistance is a complex process of physical and physiological and biochemical reactions.Soybean seed shattering phenomenon is widespread,which severely restricts the development of soybean industry.Seed shattering(pod cracking or fruit dropping)is essential for the reproduction of its offspring in wild plants,but it is also the main cause of crop yield loss.This article analyzes the morphology and structure of pods related to seed shattering from the morphology of pods.On the basis of the regularity of the occurrence of seed shattering and the summary of phenotypic index identification methods,physiologically introduced the regulation mechanism of key enzymes and endogenous hormones on seed shattering.The localization,labeling and cloning of seed shattering genes are introduced in molecular biology.The study focused on reviewing the latest advances in the research on soybean seed shattering characteristics,and discussed with the research results of related crops.Finally,the research and application of soybean seed shattering resistance were prospected for several aspects. 展开更多
关键词 Seed shattering genetic law identification mechanism of action
下载PDF
Use of A Shatter Test Vessel to Assess Propellant Safety
11
作者 Clive WOODLEY Peter HENNING 《火炸药学报》 EI CAS CSCD 北大核心 2015年第5期10-12,共3页
At low temperatures,gun propellant grains may become brittle and this can lead to fracture or shatter of the grains during gun firing.Should this event occur then it will result in an increase in the burning surface o... At low temperatures,gun propellant grains may become brittle and this can lead to fracture or shatter of the grains during gun firing.Should this event occur then it will result in an increase in the burning surface of the propellant and will give rise to a change in ballistic performance.Also,if the resultant over pressure is sufficient,a breech failure may result.Understanding the propensity of a grain to fracture or shatter is therefore important in determining its safety in use.This document describes a test that may be used to derive knowledge and to quantify the physical behaviour of a gun propellant grain at the low temperatures at which fracture or shatter is most likely to occur. 展开更多
关键词 CLOSED VESSEL SHATTER TEST PROPELLANT SAFETY
下载PDF
Identification and validation of stable and novel quantitative trait loci for pod shattering in soybean[Glycine max(L.)Merr.]
12
作者 JIA Jia WANG Huan +7 位作者 CAI Zhan-dong WEI Ru-qian HUANG Jing-hua XIA Qiu-ju XIAO Xiao-hui MA Qi-bin NIAN Hai CHENG Yan-bo 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2022年第11期3169-3184,共16页
Pod shattering is an important domesticated trait which can cause great economic loss of crop yield in cultivated soybean.In this study,we utilized two recombinant inbred line populations(RILs,CY,Huachun 2×Wayao;... Pod shattering is an important domesticated trait which can cause great economic loss of crop yield in cultivated soybean.In this study,we utilized two recombinant inbred line populations(RILs,CY,Huachun 2×Wayao;GB,Guizao 1×B13)to identify quantitative trait loci(QTLs)associated with pod shattering in soybean across multiple environments.A total of 14 QTLs for pod shattering were identified in the two RIL populations,which had LOD scores ranging from 2.64 to 44.33 with phenotypic variance explanation(PVE)ranging from 1.33 to 50.85%.One QTL qPS16-1,located on chromosome 16,included a well-known functional gene Pod dehiscence 1(Pdh1)that was reported previously.Ten new putative QTLs were validated in two RIL populations,and their LOD scores were between 2.55 and 4.24,explaining 1.33 to 2.60%of the phenotypic variation.Of which four novel QTLs(qPS01-1,qPS03-2,qPS05-1,and qPS07-1)could be detected in two environments where nine genes had specific changes in gene expression.Although the nine genes may have significant effects on pod shattering of soybean,their detailed functions still need to be further explored in the future.The results of this study will facilitate a better understanding of the genetic basis of the pod shattering-resistant trait and benefit soybean molecular breeding for improving pod shattering resistance. 展开更多
关键词 SOYBEAN pod shattering QTL mapping candidate genes
下载PDF
Mutagenic Improvement of Shattering Characteristic of the Restorer Line of a Hybrid Rice“Xieyou 9308”
13
作者 SHENSheng-quan CHENSheng-guang +2 位作者 WUDian-xing XIAYing-wu SHUQing-yao 《Rice science》 SCIE 2004年第4期222-224,共3页
The newly developed hybrid rice combination 'Xieyou 9308' (Xieqingzao A/T9308) has been regarded as a super-high-yielding rice variety, of which the yield potential reached as high as 12 t/ha. However, its hig... The newly developed hybrid rice combination 'Xieyou 9308' (Xieqingzao A/T9308) has been regarded as a super-high-yielding rice variety, of which the yield potential reached as high as 12 t/ha. However, its high shattering characteristic (as high as 60%) has limited its wider application. In the current experiment, a non-shattering mutant line, M9308, was developed from T9308 by gamma irradiation. Comparisons were made but no marked differences were found between T9308 and M9308 as well as between their F1 hybrids crossed to Xieqingzao A for major agronomic and grain quality characters as well as resistance to diseases. Genetic analysis indicated that the non-shattering character of M9308 was governed by a single recessive gene. 展开更多
关键词 hybrid rice non-shattering MUTATION high shattering character
下载PDF
Concerning Diamond and Gold-Bearing Astropipes of Mongolia
14
作者 Dorj Dorjnamjaa D. M. Voinkov +3 位作者 L. S. Kondratov D. Selenge G. Altanshagai B. Enkhbaatar 《International Journal of Astronomy and Astrophysics》 2011年第2期98-104,共7页
In this paper we present summation of thirteen year’s investigation of the all diamond-bearing structures of Mongolia. Four gold and diamond-bearing astropipe structures of exemplified by the Agit Khangay, Khuree Man... In this paper we present summation of thirteen year’s investigation of the all diamond-bearing structures of Mongolia. Four gold and diamond-bearing astropipe structures of exemplified by the Agit Khangay, Khuree Mandal, Bayan Khuree and Tsenkher astropipes of Mongolia. Detailed geological and gas-geochemical investigation of the diamond and gold-astropipe structures show that diamond genesis is an expression of collision of the lithospheric mantle with the explosion process initiated in an impact collapse meteor crater. 展开更多
关键词 Astropipe DIAMOND Impact CRATER SPHERULES Meteoritic Iron SHATTER CONES PYROPE
下载PDF
The domestication-associated L1 gene encodes a eucomic acid synthase pleiotropically modulating pod pigmentation and shattering in soybean
15
作者 Xiangguang Lyu Ying-hui Li +7 位作者 Yanfei Li Delin Li Chao Han Huilong Hong Yu Tian Lida Han Bin Liu Li-juan Qiu 《Molecular Plant》 SCIE CSCD 2023年第7期1178-1191,共14页
Pod coloration is a domestication-related trait in soybean,with modern cultivars typically displaying brown or tan pods,while their wild relative,Glycine soja,possesses black pods.However,the factors regulating this c... Pod coloration is a domestication-related trait in soybean,with modern cultivars typically displaying brown or tan pods,while their wild relative,Glycine soja,possesses black pods.However,the factors regulating this color variation remain unknown.In this study,we cloned and characterized L1,the classical locus responsible for black pods in soybean.By using map-based cloning and genetic analyses,we identified the causal gene of L1 and revealed that it encodes a hydroxymethylglutaryl-coenzyme A(CoA)lyase-like(HMGL-like)domain protein.Biochemical assays showed that L1 functions as a eucomic acid synthase and facilitates the synthesis of eucomic acid and piscidic acid,both of which contribute to coloration of pods and seed coats in soybean.Interestingly,we found that L1 plants are more prone to pod shattering under light exposure than l1 null mutants because dark pigmentation increases photothermal efficiency.Hence,pleiotropic effects of L1 on pod color and shattering,as well as seed pigmentation,likely contributed to the preference forl1 alleles during soybean domestication and improvement.Collectively,our study provides new insights into the mechanism of pod coloration and identifies a new target for future de novo domestication oflegume crops. 展开更多
关键词 SOYBEAN DOMESTICATION pod pigmentation pod shattering pleiotropic effects
原文传递
外国新书报道
16
《外国文学》 CSSCI 北大核心 1993年第1期94-94,共1页
●Time and Tide《时间和潮水》Edna O’Brien著,Viking,352pp. ●In a shattered Mirror: The Later Poetry of Ann
关键词 新书报道 安娜·阿赫玛托娃 shattered 外国 TIME 现代艺术 波德莱尔 Johannes 狄更斯 评论集
原文传递
幽默的警世性
17
作者 林羽 《当代外语研究》 1999年第9期27-29,共3页
从北京大学毕业,来到深圳工作,弹指9年逝去。求学燕园,同室的几个女孩称我为“理想主义者”。我真的愿以我“理想主义”的血肉之躯去撞击现实生活的铜墙铁壁。 在深圳,我已跳槽6次,至今没有寻觅到理想的安身立命之所,先后谈了3个男朋友... 从北京大学毕业,来到深圳工作,弹指9年逝去。求学燕园,同室的几个女孩称我为“理想主义者”。我真的愿以我“理想主义”的血肉之躯去撞击现实生活的铜墙铁壁。 在深圳,我已跳槽6次,至今没有寻觅到理想的安身立命之所,先后谈了3个男朋友,无一成功,至今,我仍孑然一身。 展开更多
关键词 天赐之福 shattered “围城” 理想主义者 矛盾修饰法 安身立命 深圳 英语学习 现实生活 修辞手法
原文传递
从“仰而望山,俯而听泉”说开去
18
作者 戎刿 《当代外语研究》 1998年第9期44-48,50,共6页
暑假,是教书匠们歇脚的风雨凉亭,是口耕舌耘者小憩的人生驿站。 此刻,无须挥汗登台,也不见案桌上山叠的作业。现代的城市生活虽难以达到韩愈在《送李愿归盘谷序》所描绘的境界:“坐茂林以终日,濯清泉以自洁。采于山,美可茹,钓于水,鲜可... 暑假,是教书匠们歇脚的风雨凉亭,是口耕舌耘者小憩的人生驿站。 此刻,无须挥汗登台,也不见案桌上山叠的作业。现代的城市生活虽难以达到韩愈在《送李愿归盘谷序》所描绘的境界:“坐茂林以终日,濯清泉以自洁。采于山,美可茹,钓于水,鲜可食。”却可以做到“起居无时,惟适之安。”晨,可朗朗诵读古今诗文,夜,可频频击水于灯影弦歌中的泳池。 展开更多
关键词 译文 汉语口语表达 性格特征 shattered 文化底蕴 形容词 汉语四字结构 “再创造” 脱离困境 《英汉大词典》
原文传递
The Puzzle of Rice Domestication 被引量:29
19
作者 Tao Sang Song Ge 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2007年第6期760-768,共9页
The origin of cultivated rice has puzzled plant biologists for decades. This is due, at least in part, to the complex evolutionary dynamics in rice cultivars and wild progenitors, particularly rapid adaptive different... The origin of cultivated rice has puzzled plant biologists for decades. This is due, at least in part, to the complex evolutionary dynamics in rice cultivars and wild progenitors, particularly rapid adaptive differentiation and continuous gene flow within and between cultivated and wild rice. The long-standing controversy over single versus multiple and annual versus perennial origins of cultivated rice has been brought into shaper focus with the rapid accumulation of genetic and phylogenetic data. Molecular phylogenetic analyses revealed ancient genomic differentiation between rice cultivars, suggesting that they were domesticated from divergent wild populations. However, the recently cloned domestication gene sh4, responsible for the reduction of grain shattering from wild to cultivated rice, seems to have originated only once. Herein, we propose two models to reconcile apparently conflicting evidence regarding rice domestication. The snowoballing model considers a single origin of cultivated rice. In this model, a core of critical domestication alleles was fixed in the founding cultivar and then acted to increase the genetic diversity of cultivars through hybridization with wild populations. The combination model considers multiple origins of cultivated rice. In this model, Initial cultivars were domesticated from divergent wild populations and fixed different sets of domestication alleles. Subsequent crosses among these semi-domesticated cultivars resulted in the fixation of a similar set of critical domestication alleles in the contemporary cultivars. In both models, introgression has played an important role in rice domestication. Recent and future introgression of beneficial genes from the wild gene pool through conventional and molecular breeding programs can be viewed as the continuation of domestication. 展开更多
关键词 Oryza sativa Oryza rufipogon Oryza nivara PHYLOGENY population genetics QTL SHATTERING sh4.
原文传递
Discovery of Shatter Cones at Jueshan Island, Taihu Lake
20
作者 王尔康 朱政 +1 位作者 张海祥 曹会 《Chinese Science Bulletin》 SCIE EI CAS 1994年第14期1210-1214,共5页
Shatter cones are conical fragments of rock characterized by striations that radiate from the apex. In 1905, they were first observed at Steinheim Basin in Germany. In the United States, the well-known occurrence site... Shatter cones are conical fragments of rock characterized by striations that radiate from the apex. In 1905, they were first observed at Steinheim Basin in Germany. In the United States, the well-known occurrence site of shatter cones is Kentland, Indiana. In 1938, when the existence of terrestrial impact crater was still a hypothesis, J. D. Boon had suggested that the structures similar to the Kentland were the products of meteoritic crater. In 1947, when making frequent investigations on Kentland quarry, R. S. Dietz pointed out that the axes of these cones were oriented normal to the bedding, with the apexes pointing toward the top of the bed. Thus, they were formed by giant forces which came from above rather than below. Because except the impact of meteorite, there is not any giant force from space, shatter cones should be 'root' of crater. This argument was proved because of the discovery 展开更多
关键词 SHATTER CONES CRATER arc FRACTURING origin of Taihu lake.
原文传递
上一页 1 2 下一页 到第
使用帮助 返回顶部