There is a strong climate gradient in the Inner Mongolia region, China, with solar radiation and air temperature increasing but precipitation decreasing gradually from the northeast to the southwest. Sixteen Cara- gan...There is a strong climate gradient in the Inner Mongolia region, China, with solar radiation and air temperature increasing but precipitation decreasing gradually from the northeast to the southwest. Sixteen Cara- gana species exist in the Inner Mongolia region. These Caragana species exhibit a distribution pattern across moisture zones and form a geographical replacement series. In order to examine the mechanisms responsible for Caragana species distribution pattern, we selected 12 Caragana species that exhibit a distinct distribution pattern across multiple moisture zones in the Inner Mongolia region, and determined the relationships between the leaf ecological and physiological traits of these Caragana species and the aridity index and solar radiation. Along with the climatic drought gradient and the solar radiation intensification from the northeast to the southwest, leaf eco- logical characteristics of Caragana species changed drastically, i.e. the leaf shape gradually turned from flat into tegular or tubbish; the leaf hair became denser, longer and lighter in color; the leaf area, leaf biomass and specific leaf area （SLA） decreased significantly; the leaf thickness and the ratio of leaf thickness to leaf area increased sig- nificantly; and the leaf chlorophyll content decreased significantly. As the climatic drought stress increased, osmotic potentials of the main osmotic adjustment substances and the cytoplasmic ion concentration of Caragana species increased significantly. Meanwhile, the total and free water contents and water potential of leaves decreased sig- nificantly; the ratio of bound to free water increased significantly; the stomatal conductance and transpiration rate reduced significantly; and the water use efficiency （WUE） increased significantly. In addition, with the intensification of climatic drought stress, peroxidase （POD） and superoxide dismutase （SOD） activities in leaves increased significantly. As a result, the malondialdehyde （MDA） content increased while the oxyg展开更多
Pre-harvest sprouting(PHS),which reduces grain yield and quality,is controlled by seed dormancy genes.Because few dormancy-related genes have been cloned,the genetic basis of seed dormancy in rice(Oryza sativa L.)rema...Pre-harvest sprouting(PHS),which reduces grain yield and quality,is controlled by seed dormancy genes.Because few dormancy-related genes have been cloned,the genetic basis of seed dormancy in rice(Oryza sativa L.)remains unclear.Here,we performed a genome-wide association study and linkage mapping to dissect the genetic basis of seed dormancy in rice.Our findings suggest that Seed Dormancy4(Sdr4),a central modulator of seed dormancy,integrates the abscisic acid and gibberellic acid signaling pathways at the transcriptional level.Haplotype analysis revealed that three Sdr4 alleles in rice cultivars already existed in ancestral Oryza rufipogon accessions.Furthermore,like the semi-dwarf 1(SD1)and Rc loci,Sdr4 underwent selection during the domestication and improvement of Asian cultivated rice.The distribution frequency of the Sdr4-n allele in different locations in Asia is negatively associated with local annual temperature and precipitation.Finally,we developed functional molecular markers for Sdr4,SD1,and Rc for use in molecular breeding.Our results provide clues about the molecular basis of Sdr4-regulated seed dormancy.Moreover,these findings provide guidance for utilizing the favorable alleles of Sdr4 and Rc to synergistically boost PHS resistance,yield,and quality in modern rice varieties.展开更多
基金funded by the National Natural Science Foundation of China (31170381, 31100330)the National Basic Research Program of China (2007CB106802)
文摘There is a strong climate gradient in the Inner Mongolia region, China, with solar radiation and air temperature increasing but precipitation decreasing gradually from the northeast to the southwest. Sixteen Cara- gana species exist in the Inner Mongolia region. These Caragana species exhibit a distribution pattern across moisture zones and form a geographical replacement series. In order to examine the mechanisms responsible for Caragana species distribution pattern, we selected 12 Caragana species that exhibit a distinct distribution pattern across multiple moisture zones in the Inner Mongolia region, and determined the relationships between the leaf ecological and physiological traits of these Caragana species and the aridity index and solar radiation. Along with the climatic drought gradient and the solar radiation intensification from the northeast to the southwest, leaf eco- logical characteristics of Caragana species changed drastically, i.e. the leaf shape gradually turned from flat into tegular or tubbish; the leaf hair became denser, longer and lighter in color; the leaf area, leaf biomass and specific leaf area （SLA） decreased significantly; the leaf thickness and the ratio of leaf thickness to leaf area increased sig- nificantly; and the leaf chlorophyll content decreased significantly. As the climatic drought stress increased, osmotic potentials of the main osmotic adjustment substances and the cytoplasmic ion concentration of Caragana species increased significantly. Meanwhile, the total and free water contents and water potential of leaves decreased sig- nificantly; the ratio of bound to free water increased significantly; the stomatal conductance and transpiration rate reduced significantly; and the water use efficiency （WUE） increased significantly. In addition, with the intensification of climatic drought stress, peroxidase （POD） and superoxide dismutase （SOD） activities in leaves increased significantly. As a result, the malondialdehyde （MDA） content increased while the oxyg
基金supported by the National Natural Science Foundation of China (32001612)the Science, Technology and Innovation Commission of Shenzhen Municipality (JCYJ20180306173702268 and KCXFZ20201221173203009)+2 种基金Key-Area Research and Development Program of Guangdong Province (2021B0707010006)Dapeng New District Science and Technology Program (KJYF202101-09 and RCTD20180102)Guangdong Basic and Applied Basic Research Foundation (2019A1515110966)
文摘Pre-harvest sprouting(PHS),which reduces grain yield and quality,is controlled by seed dormancy genes.Because few dormancy-related genes have been cloned,the genetic basis of seed dormancy in rice(Oryza sativa L.)remains unclear.Here,we performed a genome-wide association study and linkage mapping to dissect the genetic basis of seed dormancy in rice.Our findings suggest that Seed Dormancy4(Sdr4),a central modulator of seed dormancy,integrates the abscisic acid and gibberellic acid signaling pathways at the transcriptional level.Haplotype analysis revealed that three Sdr4 alleles in rice cultivars already existed in ancestral Oryza rufipogon accessions.Furthermore,like the semi-dwarf 1(SD1)and Rc loci,Sdr4 underwent selection during the domestication and improvement of Asian cultivated rice.The distribution frequency of the Sdr4-n allele in different locations in Asia is negatively associated with local annual temperature and precipitation.Finally,we developed functional molecular markers for Sdr4,SD1,and Rc for use in molecular breeding.Our results provide clues about the molecular basis of Sdr4-regulated seed dormancy.Moreover,these findings provide guidance for utilizing the favorable alleles of Sdr4 and Rc to synergistically boost PHS resistance,yield,and quality in modern rice varieties.
