Spatial heterogeneity is a ubiquitous feature in natural ecosystems, especially in arid regions. Different species and their discontinuous distribution, accompanied by varied topographic characteristics, result in soi...Spatial heterogeneity is a ubiquitous feature in natural ecosystems, especially in arid regions. Different species and their discontinuous distribution, accompanied by varied topographic characteristics, result in soil resources distributed differently in different locations, and present significant spatial heterogeneity in desert ecosystems. In this study, conventional and geostatistical methods were used to identify the heterogeneity of soil chemical properties in two desert populations, Haloxylon persicum Bunge ex Boss., which dominates on the slopes and tops of sand dunes and Haloxylon ammodendron (C. A. Mey.) Bunge, which inhabits interdunes in the Gurbantunggut Desert of Xinjiang, China. The results showed that soil pH, electrical conductivity (EC), soil organic carbon (SOC), available nitrogen (AN) and available phosphorus (AP) were significantly higher in H. ammodendron populations than that in H. persicum. The coefficient of variation (CV) indicated that (1) most parameters presented a moderate degree of variability (10% 【 CV 【 100%) except pH in both plots, (2) the variability of soil pH, EC and AP in H. ammodendron populations was higher than that in H. persicum populations, and (3) SOC and AN in H. ammodendron populations were lower than that in H. persicum populations. Geostatistical analysis revealed a strong spatial dependence (C0/(C0+C) 【 25%) within the distance of ranges for all tested parameters in both plots. The Kriging-interpolated figures showed that the soil spatial distribution was correlated with the vegetation distribution, individual size of plants, and the topographic features, especially with the plants nearest to sampling points and the topographic features. In each plot, soil EC, SOC, AN and AP presented similar distributions, and fertile islands and salt islands occurred in both plots but did not affect every individual plant, since the sampling distance was larger than the size of such fertile islands. The results of topographic effects on soil heterogeneity suggested si展开更多
: For the sake of providing some important information relevant to the study of the molecular mechanism of genic male sterility in plants, gene differential expression in flower buds at different developmental stages,...: For the sake of providing some important information relevant to the study of the molecular mechanism of genic male sterility in plants, gene differential expression in flower buds at different developmental stages, as well as in rosette leaves, florescence leaves, and scapes was analyzed using cDNA amplified fragment length polymorphism (cDNA-AFLP) in the genic male sterile A and fertile B line of Chinese cabbage pak-choi. Following amplification of 125 pairs of primer combinations, 11 differential fragments were obtained, of which eight were from the B line and the other three were from the A line. Of 11 differential fragments, four were verified by Northern hybridization that were expressed preferentially in fertile flower buds. Results of GenBank BLAST showed that one fragment was with unknown function, whereas the other fragments have strong nucleotide sequence similarities with the polygalacturonase (PG) gene, the pectinesterase (PE) gene, and the polygalacturonase inhibitory protein (PGIP4) gene. Only full-length cDNA from the differential fragment BcMF-A18T16-1 was amplified by rapid amplification of cDNA ends (RACE) and Northern analysis showed that this fragment was expressed only in medium and large-sized flower buds of the B line. The full-length cDNA, designated as BcMF2 (Brassica campestris Male Fertile 2), was 1 485 bp long and was composed of a 1 263-bp open reading frame, which had 83% nucleotide similarity to a PG gene from Arabidopsis encoding polygalacturonase. Analysis of the basic structure of the protein revealed that it had one polygalacturonase active site (RVTCGPGHGLSVGS) at 256th site of amino acids and was classified as being a member of family 28 of the glycosyl hydrolases. The role of the BcMF2 gene on microspore development is discussed in the present paper.展开更多
Introduction: Solitary exostoses are the most common benign tumors of the fertile metaphyses of the long bones of children. Their radiological diagnosis of metaphyseal bone growth must be confirmed on pathological exa...Introduction: Solitary exostoses are the most common benign tumors of the fertile metaphyses of the long bones of children. Their radiological diagnosis of metaphyseal bone growth must be confirmed on pathological examination. These tumors can remain asymptomatic for a long time and reveal themselves during a particularly vascular complication. The objective of this study was to describe the epidemiological, diagnostic, therapeutic and evolutionary aspects of these tumors. Patient and Observation: We report the case of a 15-year-old adolescent girl, with no particular pathological history, received in the pediatric surgery department of the Donka National Hospital (HND) of the Conakry University Hospital for recurrent acute painful swelling of the lower third of the left thigh in an afebrile context accompanied by lameness and stopping school for a few days (2 - 3 days). The symptoms appear to have evolved over the past 3 years and after physical activities. It regresses with rest, analgesics and non-steroidal anti-inflammatory drugs. The notion of trauma and sickle cell disease was not reported in the patient's clinical history. It is the persistence of the symptomatology which motivates the said consultation. On palpation, a small hard mass is noted at the expense of the internal metaphysis of the left distal femur. Deep palpation of this area causes a tingling sensation and during rapid mobilization of the knee. The remainder of the orthopedic examination was unremarkable. Standard x-ray of the femur shows a bony growth with a pointed tip from the distal metaphysis of the left femur. On surgical exploration, we noted a wedge-shaped exostosis oriented towards the vastus medialis muscle. Histological examination of the surgical specimen confirms osteogenic exostosis. There is no recurrence after 2 years. Conclusion: The distal femoral metaphysis is the most common location of solitary osteochondromas in children. Their definitive diagnosis requires the histology of the surgical specimen. Only symptomatic exostos展开更多
The current margins of the North China and Yangtze Cratons provide arguably the best examples globally of anomalously high mineral endowment within a 100 km buffer zone,hosting 66 diverse world-class to giant ore syst...The current margins of the North China and Yangtze Cratons provide arguably the best examples globally of anomalously high mineral endowment within a 100 km buffer zone,hosting 66 diverse world-class to giant ore systems that help explain China’s premier position as a producer of multiple metal and mineral commodities.After the cratonization of these crustal blocks during the Neoarchean-Paleoproterozoic,with incorporation of iron ores on assembled micro-block margins,the margins of the cratons experienced multiple convergence and rifting events leading to metasomatism and fertilization of their underlying sub-continental lithospheric mantle.The rifted margins with trans-lithosphere faults provided pathways for Cu-Au(Mo-W-Sn)-bearing felsic to Ni-Cu-bearing ultrabasic intrusions and REE-rich carbonatite magmas,and for the development of marginal sedimentary basins with both Cu-Pb-Zn-rich source units and reactive carbonate or carbonaceous host rocks.There was diachronous formation of hydrothermal orogenic gold,antimony,and bismuth systems in the narrow orogenic belts between the cratons.Complexity in the Mesozoic Paleo-Pacific subduction systems resulted in asthenosphere upwelling and lithosphere extension and thinning in the North China Craton,leading to anomalous heat flow and formation of orogenic gold deposits,including those of the giant Jiaodong gold province on its north-eastern margin.These gold deposits,many of which formed from fluids liberated by devolatilization of previously metasomatized sub-continental lithospheric mantle,helped propel China to be the premier gold producer globally.The thick sub-continental lithospheric mantle of the cold buoyant cratons helped the preservation of some of the world’s oldest porphyry-skarn and epithermal mineral systems.Although craton margins globally control the formation and preservation of a diverse range of mineral deposits,China represents the premier example in terms of metal endowment due to the anomalous length of its craton margins combined with their a展开更多
377 isolates of Magnaporthe grisea were collected from 17 provinces in China and their geographic distribution of mating types and their fertility was tested with four standard isolates, KA3 and TH12 (Mat1.1) and Guy1...377 isolates of Magnaporthe grisea were collected from 17 provinces in China and their geographic distribution of mating types and their fertility was tested with four standard isolates, KA3 and TH12 (Mat1.1) and Guy11 and TH16 (Mat1.2) provided by CIRAD. 73 fertile isolates were tested with SCAR markers of 13 pairs of primers. Preliminary results showed that the geographic distribution of M.grisea existed among isolates collected from the same location as well as different locations and the genetic relationship between fertile isolates of the fungus in China. The existence of sexual reproduction of M .grisea was explored in the field as well.展开更多
Promoting more floret primordia within a spike to acquire fertile potential during the differentiation and pre-dimorphism phases is critical for increasing the number of fertile florets per spike(NFFs).However,it is y...Promoting more floret primordia within a spike to acquire fertile potential during the differentiation and pre-dimorphism phases is critical for increasing the number of fertile florets per spike(NFFs).However,it is yet unknown the physiological mechanism regulating the complex and dynamic process.This study aimed to clarify how intra-spike hormones,pigments,and assimilates coordinate with each other to regulate spike morphology and then floret primordia development.A two-year field experiment was conducted with two winter wheat genotypes:N50(big-spike with greater NFFs)and SM22(mediumspike with fewer NFFs).We monitored high temporal and spatial-resolution changes in the number and morphology of floret primordia within a spike,as well as in intra-spike hormones,pigments,and assimilates.Our results revealed that the big-spike genotype had more NFFs than the medium-spike genotype,not only because they had more spikelets,but also because they had greater NFFs mainly at central spikelets.More floret primordia at central spikelets had sufficient time to develop and acquire fertile potential during the differentiation phase(167-176 d after sowing,DAS)and the pre-dimorphism phase(179 DAS)for the big-spike genotype than the medium-spike genotype.Floret primordia with fertile morphology during the pre-dimorphism phase always developed into fertile florets during the dimorphism phase.Those early-developed floret primordia most proximal and intermediate to the rachis in the big-spike genotype developed faster than the medium-spike genotype.Correspondingly,the spike dry matter and pigments(chlorophyll a,chlorophyll b,carotene,and carotenoids)content during 170-182 DAS,auxin(IAA)and cytokinin(CTK)content on 167 DAS were significantly higher in the big-spike genotype than in the medium-spike genotype,while jasmonic acid(JA)content was significantly lower in the big-spike genotype compared to the medium-spike genotype during 167-182 DAS.Since the significant differences in intra-spike hormone content of the two genotypes appear展开更多
Nitrogen(N)fertilization is critical for spike and floret development,which affects the number of fertile florets per spike(NFFs).However,the physiological regulation of the floret development process by N fertilizati...Nitrogen(N)fertilization is critical for spike and floret development,which affects the number of fertile florets per spike(NFFs).However,the physiological regulation of the floret development process by N fertilization is largely unknown.A high temporal-resolution investigation of floret primordia number and morphology,dry matter,and N availability was conducted under three N fertilization levels:0(N0),120(N1)and 240(N2)kg ha^(−1).Interestingly,fertile florets at anthesis stage were determined by those floret primordia with meiotic ability at booting stage:meiotic ability was a threshold that predicted whether a floret primordium became fertile or abortive florets.Because the developmental rate of the 4th floret primordium in the central spikelet was accelerated and then they acquired meiotic ability,the NFFs increased gradually as N application increased,but the increase range decreased under N2.There were no differences in spike N concentration among treatments,but leaf N concentration was increased in the N1 and N2 treatments.Correspondingly,dry matter accumulation and N content of the leaf and spike in the N1 and N2 treatments was increased as compared to N0.Clearly,optimal N fertilization increased leaf N availability and transport of assimilates to spikes,and allowed more floret primordia to acquire meiotic ability and become fertile florets,finally increasing NFFs.There was no difference in leaf N concentration between N1 and N2 treatment,whereas soil N concentration at 0–60 cm soil layers was higher in N2 than in N1 treatment,implying that there was still some N fertilization that remained unused.Therefore,improving the leaf’s ability to further use N fertilizer is vital for greater NFFs.展开更多
Some haplotypes of the sucrose synthase gene TaSus1 are associated with thousand-grain weight(TGW)in wheat(Triticum aestivum L.).However,no mutations have been identified within the gene to test this association.The e...Some haplotypes of the sucrose synthase gene TaSus1 are associated with thousand-grain weight(TGW)in wheat(Triticum aestivum L.).However,no mutations have been identified within the gene to test this association.The effects of TaSus1 on grain number per spike(GNS)also are largely unknown.Our previous genome-wide association study identified TaSus-A1 as a candidate gene controlling fertile spikelet number per spike(FSN).In the present study,we generated two independent mutants for the three TaSus1 homoeologs by CRISPR/Cas9-mediated genome editing.The triple mutants displayed lower FSN,GNS,grain number per spikelet(GNST),and TGW than wild-type plants.In 306 hexaploid wheat accessions,two single-nucleotide polymorphisms in TaSus-A1 contributed differently to GNS.Introgression of the two alleles into a wheat genetic background confirmed their effects.The alleles differed in geographical distribution among the accessions.展开更多
Sperm head morphology is crucial for male factor infertility diagnosis and assessment of male reproductive potential.Severalcriteria are available to analyze sperm head morphology,but they are limited by poor methodol...Sperm head morphology is crucial for male factor infertility diagnosis and assessment of male reproductive potential.Severalcriteria are available to analyze sperm head morphology,but they are limited by poor methodology comparability and populationapplicability.This study aimed to explore comprehensive and new normal morphometric reference values for spermatozoa heads infertile Asian males.An automated sperm morphology analysis system captured 23152 stained spermatozoa from confirmed fertilemales.Of these samples,1856 sperm head images were annotated by three experienced laboratory technicians as“normal”.Weemployed 14 novel morphometric features to describe sperm head size(head length,head width,length/width ratio,and girth),shape(ellipse intersection over union,girth intersection over union,short-axis symmetry,and long-axis symmetry),area(head,acrosome,postacrosomal areas,and acrosome area ratio),and degrees of acrosome and nuclear uniformity.This straight-forwardmethod for the morphometric analysis of sperm by accurate visual measurements is clinically applicable.The measured parameterspresent valuable information to establish morphometric reference intervals for normal sperm heads in fertile Asian males.Thepresented detailed measurement data will be valuable for interlaboratory comparisons and technician training.In vitro fertilizationand andrology laboratory technicians can use these parameters to perform objective morphology evaluation when assessing malefertilization potential.展开更多
Semen samples were collected from 1213 fertile men whose partners had a time-to-pregnancy （TTP） _〈12 months in Guangdong Province in Southern China, and semen parameters including semen volume, sperm concentration,...Semen samples were collected from 1213 fertile men whose partners had a time-to-pregnancy （TTP） _〈12 months in Guangdong Province in Southern China, and semen parameters including semen volume, sperm concentration, total counts, motility, and morphology were evaluated according to the World Health Organization （WHO） 2010 guideline. All semen parameters analyzed were normal in ~62.2% of the total samples, whereas 37.8% showed at least one of the semen parameters below normal threshold values. The fifth centiles （with 95% confidence intervals） were 1.3 （1.2-1.5） ml for semen volume, 20 x 106 （18x106- 20x106） m1-1 for sperm concentration, 40 x 106 （38x106-44x106） per ejaculate for total sperm counts, 48% （47%-53%） for vitality, 39% （36%-43%） for total motility, 25% （23%-27%） for sperm progressive motility, 5.0% （4%,5%） for normal morphology. The pH values ranged from 7.2 to 8.0 with the mean ~ standard deviation at 7.32 ~ 0.17. No effects of age and body mass index were found on semen parameters. Occupation, smoking and alcohol abuse, varicocele appeared to decrease semen quality. Sperm concentration, but not sperm morphology, is positively correlated with TTP, whereas vitality is negatively correlated with TTP. Our study provides the latest reference values for the semen parameters of Chinese fertile men in Guangdong Province, which are close to those described in the new WHO guidelines （5th Edition）.展开更多
Iraq is part of the Fertile Crescent with the two large rivers:Tigris and Euphrates and their tributaries that secure the required quantity and quality of water to the Iraqi population for their different uses;includi...Iraq is part of the Fertile Crescent with the two large rivers:Tigris and Euphrates and their tributaries that secure the required quantity and quality of water to the Iraqi population for their different uses;including agriculture,industry,and other domestic requirements.During the last decades,however,the quantity and quality of water in these rivers decreased causing water scarcity in the country.This scarcity is having severe impacts on food security in Iraq since large cultivated areas in different parts of the country that grow different agricultural products have been abandoned due to lack of water.The worsening situation is attributed mainly to global climate changes including decreasing rainfall amounts,increase in air temperature,and insufficient water inflows in the two main rivers and their tributaries.This last issue is exasperated by the unfair water sharing policies of the riparian countries namely Turkey and Iran.In writing this article relevant data from different sources were used.Numerous published reports and papers dealing with this important issue were consulted,while at the same time,the long experience of the authors in these very important issues was also drawn upon to elucidate the difficulties that are current today and those expected in the future in this field.展开更多
Exotic plant invasion is a growing concern in the conservation and management of indigenous arid land ecosystems. By creating areas of ameliorated microclimates and fertile soil below their canopies, perennial plants ...Exotic plant invasion is a growing concern in the conservation and management of indigenous arid land ecosystems. By creating areas of ameliorated microclimates and fertile soil below their canopies, perennial plants might influence exotic annual plant invasions. We conducted a quantitative literature review of studies that compared exotic annual plant abundance among native perennial plant species and interspace （open areas） microsites in North America＇s Mojave Desert, where exotic plant invasion has corresponded with increasing extent of wildfire and broad-scale ecosystem transformation. Ten studies compared exotic annual plant abundance between inter- spaces and below a total of 36 native perennial species. These studies revealed that： （1） With few exceptions, most native perennial species supported a greater abundance of exotic annuals than interspaces, indicating overall facilitation of exotic species by native perennials. （2） Exotic species abundance varied by orders of magnitude among native perennial species, with some perennial species harboring amounts of exotics similar to interspaces. （3） Distributions of dominant exotic species varied, where Bromus rubens displayed a greater affinity for below-perennial microsites than did Schismus spp. and Erodium cicutarium that often were most abundant in interspaces. Results suggest that the degree of facilitation of exotic plants warrants consideration when selecting native perennial species for revegetation and restoration projects.展开更多
Arisaema tosaense Makino develops either 1 or 2 leaves during both the male and female phases. To clarify the relationship between growth stage (sexual stage) and leaf number in this species, we conducted morphologica...Arisaema tosaense Makino develops either 1 or 2 leaves during both the male and female phases. To clarify the relationship between growth stage (sexual stage) and leaf number in this species, we conducted morphological analysis using A. tosaense, A. japonicum Bulme, A. sikokianum French. & Sav., and A. ringens (Thunb.) Schott. We found that increase in size of pseudostem of these Arisaema species is correlated to changes in the growth stage from sterile to male and from male to female phases. In particular, 1-leaf individuals of A. tosaense appeared at the beginning of both male and female phases, suggesting that they contribute to the earlier appearance of the fertile phase from sterile展开更多
基金supported by the National Natural Science Foundation of China (40701187)the Western Light Project of the Chinese Academy of Sciences (XBBS200808)
文摘Spatial heterogeneity is a ubiquitous feature in natural ecosystems, especially in arid regions. Different species and their discontinuous distribution, accompanied by varied topographic characteristics, result in soil resources distributed differently in different locations, and present significant spatial heterogeneity in desert ecosystems. In this study, conventional and geostatistical methods were used to identify the heterogeneity of soil chemical properties in two desert populations, Haloxylon persicum Bunge ex Boss., which dominates on the slopes and tops of sand dunes and Haloxylon ammodendron (C. A. Mey.) Bunge, which inhabits interdunes in the Gurbantunggut Desert of Xinjiang, China. The results showed that soil pH, electrical conductivity (EC), soil organic carbon (SOC), available nitrogen (AN) and available phosphorus (AP) were significantly higher in H. ammodendron populations than that in H. persicum. The coefficient of variation (CV) indicated that (1) most parameters presented a moderate degree of variability (10% 【 CV 【 100%) except pH in both plots, (2) the variability of soil pH, EC and AP in H. ammodendron populations was higher than that in H. persicum populations, and (3) SOC and AN in H. ammodendron populations were lower than that in H. persicum populations. Geostatistical analysis revealed a strong spatial dependence (C0/(C0+C) 【 25%) within the distance of ranges for all tested parameters in both plots. The Kriging-interpolated figures showed that the soil spatial distribution was correlated with the vegetation distribution, individual size of plants, and the topographic features, especially with the plants nearest to sampling points and the topographic features. In each plot, soil EC, SOC, AN and AP presented similar distributions, and fertile islands and salt islands occurred in both plots but did not affect every individual plant, since the sampling distance was larger than the size of such fertile islands. The results of topographic effects on soil heterogeneity suggested si
基金国家自然科学基金，the Key Sci-Technology Project of Zhejiang Province,China
文摘: For the sake of providing some important information relevant to the study of the molecular mechanism of genic male sterility in plants, gene differential expression in flower buds at different developmental stages, as well as in rosette leaves, florescence leaves, and scapes was analyzed using cDNA amplified fragment length polymorphism (cDNA-AFLP) in the genic male sterile A and fertile B line of Chinese cabbage pak-choi. Following amplification of 125 pairs of primer combinations, 11 differential fragments were obtained, of which eight were from the B line and the other three were from the A line. Of 11 differential fragments, four were verified by Northern hybridization that were expressed preferentially in fertile flower buds. Results of GenBank BLAST showed that one fragment was with unknown function, whereas the other fragments have strong nucleotide sequence similarities with the polygalacturonase (PG) gene, the pectinesterase (PE) gene, and the polygalacturonase inhibitory protein (PGIP4) gene. Only full-length cDNA from the differential fragment BcMF-A18T16-1 was amplified by rapid amplification of cDNA ends (RACE) and Northern analysis showed that this fragment was expressed only in medium and large-sized flower buds of the B line. The full-length cDNA, designated as BcMF2 (Brassica campestris Male Fertile 2), was 1 485 bp long and was composed of a 1 263-bp open reading frame, which had 83% nucleotide similarity to a PG gene from Arabidopsis encoding polygalacturonase. Analysis of the basic structure of the protein revealed that it had one polygalacturonase active site (RVTCGPGHGLSVGS) at 256th site of amino acids and was classified as being a member of family 28 of the glycosyl hydrolases. The role of the BcMF2 gene on microspore development is discussed in the present paper.
文摘Introduction: Solitary exostoses are the most common benign tumors of the fertile metaphyses of the long bones of children. Their radiological diagnosis of metaphyseal bone growth must be confirmed on pathological examination. These tumors can remain asymptomatic for a long time and reveal themselves during a particularly vascular complication. The objective of this study was to describe the epidemiological, diagnostic, therapeutic and evolutionary aspects of these tumors. Patient and Observation: We report the case of a 15-year-old adolescent girl, with no particular pathological history, received in the pediatric surgery department of the Donka National Hospital (HND) of the Conakry University Hospital for recurrent acute painful swelling of the lower third of the left thigh in an afebrile context accompanied by lameness and stopping school for a few days (2 - 3 days). The symptoms appear to have evolved over the past 3 years and after physical activities. It regresses with rest, analgesics and non-steroidal anti-inflammatory drugs. The notion of trauma and sickle cell disease was not reported in the patient's clinical history. It is the persistence of the symptomatology which motivates the said consultation. On palpation, a small hard mass is noted at the expense of the internal metaphysis of the left distal femur. Deep palpation of this area causes a tingling sensation and during rapid mobilization of the knee. The remainder of the orthopedic examination was unremarkable. Standard x-ray of the femur shows a bony growth with a pointed tip from the distal metaphysis of the left femur. On surgical exploration, we noted a wedge-shaped exostosis oriented towards the vastus medialis muscle. Histological examination of the surgical specimen confirms osteogenic exostosis. There is no recurrence after 2 years. Conclusion: The distal femoral metaphysis is the most common location of solitary osteochondromas in children. Their definitive diagnosis requires the histology of the surgical specimen. Only symptomatic exostos
基金partly funded by the National Key Research Program of China(2019YFA0708603)the National Natural Science Foundation of China(42130801,41230311,41572069,41702070)+2 种基金the 111 Project of the Ministry of Science and Technology,China(BP0719021)the MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences(MSFGPMR201804)the Key Laboratory of Gold Mineralization Processes and Resource Utilization Subordinated to the Ministry of Natural Resources and Key Laboratory of Metallogenic Geological Process and Resources Utilization in Shandong Province,Shandong Institute of Geological Sciences(KFKT201801,KFKT201802)。
文摘The current margins of the North China and Yangtze Cratons provide arguably the best examples globally of anomalously high mineral endowment within a 100 km buffer zone,hosting 66 diverse world-class to giant ore systems that help explain China’s premier position as a producer of multiple metal and mineral commodities.After the cratonization of these crustal blocks during the Neoarchean-Paleoproterozoic,with incorporation of iron ores on assembled micro-block margins,the margins of the cratons experienced multiple convergence and rifting events leading to metasomatism and fertilization of their underlying sub-continental lithospheric mantle.The rifted margins with trans-lithosphere faults provided pathways for Cu-Au(Mo-W-Sn)-bearing felsic to Ni-Cu-bearing ultrabasic intrusions and REE-rich carbonatite magmas,and for the development of marginal sedimentary basins with both Cu-Pb-Zn-rich source units and reactive carbonate or carbonaceous host rocks.There was diachronous formation of hydrothermal orogenic gold,antimony,and bismuth systems in the narrow orogenic belts between the cratons.Complexity in the Mesozoic Paleo-Pacific subduction systems resulted in asthenosphere upwelling and lithosphere extension and thinning in the North China Craton,leading to anomalous heat flow and formation of orogenic gold deposits,including those of the giant Jiaodong gold province on its north-eastern margin.These gold deposits,many of which formed from fluids liberated by devolatilization of previously metasomatized sub-continental lithospheric mantle,helped propel China to be the premier gold producer globally.The thick sub-continental lithospheric mantle of the cold buoyant cratons helped the preservation of some of the world’s oldest porphyry-skarn and epithermal mineral systems.Although craton margins globally control the formation and preservation of a diverse range of mineral deposits,China represents the premier example in terms of metal endowment due to the anomalous length of its craton margins combined with their a
文摘377 isolates of Magnaporthe grisea were collected from 17 provinces in China and their geographic distribution of mating types and their fertility was tested with four standard isolates, KA3 and TH12 (Mat1.1) and Guy11 and TH16 (Mat1.2) provided by CIRAD. 73 fertile isolates were tested with SCAR markers of 13 pairs of primers. Preliminary results showed that the geographic distribution of M.grisea existed among isolates collected from the same location as well as different locations and the genetic relationship between fertile isolates of the fungus in China. The existence of sexual reproduction of M .grisea was explored in the field as well.
基金funded by the Scientific and Technological Innovation Team Project of Seed Industry for Saline-alkali Tolerant Crop in Hebei Province(23327501D)the National Key Research and Development Program of China(2022YFD2300802,2022YFD1900703)the China Agriculture Research System(CARS-3).
文摘Promoting more floret primordia within a spike to acquire fertile potential during the differentiation and pre-dimorphism phases is critical for increasing the number of fertile florets per spike(NFFs).However,it is yet unknown the physiological mechanism regulating the complex and dynamic process.This study aimed to clarify how intra-spike hormones,pigments,and assimilates coordinate with each other to regulate spike morphology and then floret primordia development.A two-year field experiment was conducted with two winter wheat genotypes:N50(big-spike with greater NFFs)and SM22(mediumspike with fewer NFFs).We monitored high temporal and spatial-resolution changes in the number and morphology of floret primordia within a spike,as well as in intra-spike hormones,pigments,and assimilates.Our results revealed that the big-spike genotype had more NFFs than the medium-spike genotype,not only because they had more spikelets,but also because they had greater NFFs mainly at central spikelets.More floret primordia at central spikelets had sufficient time to develop and acquire fertile potential during the differentiation phase(167-176 d after sowing,DAS)and the pre-dimorphism phase(179 DAS)for the big-spike genotype than the medium-spike genotype.Floret primordia with fertile morphology during the pre-dimorphism phase always developed into fertile florets during the dimorphism phase.Those early-developed floret primordia most proximal and intermediate to the rachis in the big-spike genotype developed faster than the medium-spike genotype.Correspondingly,the spike dry matter and pigments(chlorophyll a,chlorophyll b,carotene,and carotenoids)content during 170-182 DAS,auxin(IAA)and cytokinin(CTK)content on 167 DAS were significantly higher in the big-spike genotype than in the medium-spike genotype,while jasmonic acid(JA)content was significantly lower in the big-spike genotype compared to the medium-spike genotype during 167-182 DAS.Since the significant differences in intra-spike hormone content of the two genotypes appear
基金This study was supported by the National Key Research and Development Program of China(2022YFD1900703,2022YFD2300802)the Earmarked Fund for CARS(CARS-3)+1 种基金the National Natural Science Foundation of China(31871563)China Postdoctoral Science Foundation(2022M723437).
文摘Nitrogen(N)fertilization is critical for spike and floret development,which affects the number of fertile florets per spike(NFFs).However,the physiological regulation of the floret development process by N fertilization is largely unknown.A high temporal-resolution investigation of floret primordia number and morphology,dry matter,and N availability was conducted under three N fertilization levels:0(N0),120(N1)and 240(N2)kg ha^(−1).Interestingly,fertile florets at anthesis stage were determined by those floret primordia with meiotic ability at booting stage:meiotic ability was a threshold that predicted whether a floret primordium became fertile or abortive florets.Because the developmental rate of the 4th floret primordium in the central spikelet was accelerated and then they acquired meiotic ability,the NFFs increased gradually as N application increased,but the increase range decreased under N2.There were no differences in spike N concentration among treatments,but leaf N concentration was increased in the N1 and N2 treatments.Correspondingly,dry matter accumulation and N content of the leaf and spike in the N1 and N2 treatments was increased as compared to N0.Clearly,optimal N fertilization increased leaf N availability and transport of assimilates to spikes,and allowed more floret primordia to acquire meiotic ability and become fertile florets,finally increasing NFFs.There was no difference in leaf N concentration between N1 and N2 treatment,whereas soil N concentration at 0–60 cm soil layers was higher in N2 than in N1 treatment,implying that there was still some N fertilization that remained unused.Therefore,improving the leaf’s ability to further use N fertilizer is vital for greater NFFs.
基金This work was supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDA24010104-2).
文摘Some haplotypes of the sucrose synthase gene TaSus1 are associated with thousand-grain weight(TGW)in wheat(Triticum aestivum L.).However,no mutations have been identified within the gene to test this association.The effects of TaSus1 on grain number per spike(GNS)also are largely unknown.Our previous genome-wide association study identified TaSus-A1 as a candidate gene controlling fertile spikelet number per spike(FSN).In the present study,we generated two independent mutants for the three TaSus1 homoeologs by CRISPR/Cas9-mediated genome editing.The triple mutants displayed lower FSN,GNS,grain number per spikelet(GNST),and TGW than wild-type plants.In 306 hexaploid wheat accessions,two single-nucleotide polymorphisms in TaSus-A1 contributed differently to GNS.Introgression of the two alleles into a wheat genetic background confirmed their effects.The alleles differed in geographical distribution among the accessions.
基金supported by the National Natural Science Foundation of China(No.81974226,No.32171264,and No.81974365)the Sichuan Science and Technology Program(No.2021YFS0026 and No.2022YFS0045).
文摘Sperm head morphology is crucial for male factor infertility diagnosis and assessment of male reproductive potential.Severalcriteria are available to analyze sperm head morphology,but they are limited by poor methodology comparability and populationapplicability.This study aimed to explore comprehensive and new normal morphometric reference values for spermatozoa heads infertile Asian males.An automated sperm morphology analysis system captured 23152 stained spermatozoa from confirmed fertilemales.Of these samples,1856 sperm head images were annotated by three experienced laboratory technicians as“normal”.Weemployed 14 novel morphometric features to describe sperm head size(head length,head width,length/width ratio,and girth),shape(ellipse intersection over union,girth intersection over union,short-axis symmetry,and long-axis symmetry),area(head,acrosome,postacrosomal areas,and acrosome area ratio),and degrees of acrosome and nuclear uniformity.This straight-forwardmethod for the morphometric analysis of sperm by accurate visual measurements is clinically applicable.The measured parameterspresent valuable information to establish morphometric reference intervals for normal sperm heads in fertile Asian males.Thepresented detailed measurement data will be valuable for interlaboratory comparisons and technician training.In vitro fertilizationand andrology laboratory technicians can use these parameters to perform objective morphology evaluation when assessing malefertilization potential.
文摘Semen samples were collected from 1213 fertile men whose partners had a time-to-pregnancy （TTP） _〈12 months in Guangdong Province in Southern China, and semen parameters including semen volume, sperm concentration, total counts, motility, and morphology were evaluated according to the World Health Organization （WHO） 2010 guideline. All semen parameters analyzed were normal in ~62.2% of the total samples, whereas 37.8% showed at least one of the semen parameters below normal threshold values. The fifth centiles （with 95% confidence intervals） were 1.3 （1.2-1.5） ml for semen volume, 20 x 106 （18x106- 20x106） m1-1 for sperm concentration, 40 x 106 （38x106-44x106） per ejaculate for total sperm counts, 48% （47%-53%） for vitality, 39% （36%-43%） for total motility, 25% （23%-27%） for sperm progressive motility, 5.0% （4%,5%） for normal morphology. The pH values ranged from 7.2 to 8.0 with the mean ~ standard deviation at 7.32 ~ 0.17. No effects of age and body mass index were found on semen parameters. Occupation, smoking and alcohol abuse, varicocele appeared to decrease semen quality. Sperm concentration, but not sperm morphology, is positively correlated with TTP, whereas vitality is negatively correlated with TTP. Our study provides the latest reference values for the semen parameters of Chinese fertile men in Guangdong Province, which are close to those described in the new WHO guidelines （5th Edition）.
文摘Iraq is part of the Fertile Crescent with the two large rivers:Tigris and Euphrates and their tributaries that secure the required quantity and quality of water to the Iraqi population for their different uses;including agriculture,industry,and other domestic requirements.During the last decades,however,the quantity and quality of water in these rivers decreased causing water scarcity in the country.This scarcity is having severe impacts on food security in Iraq since large cultivated areas in different parts of the country that grow different agricultural products have been abandoned due to lack of water.The worsening situation is attributed mainly to global climate changes including decreasing rainfall amounts,increase in air temperature,and insufficient water inflows in the two main rivers and their tributaries.This last issue is exasperated by the unfair water sharing policies of the riparian countries namely Turkey and Iran.In writing this article relevant data from different sources were used.Numerous published reports and papers dealing with this important issue were consulted,while at the same time,the long experience of the authors in these very important issues was also drawn upon to elucidate the difficulties that are current today and those expected in the future in this field.
基金facilitated by funding provided by cooperative agreements between the National Park Service (Lake Mead National Recreation Area,in particular Alice NEWTON) and the University of Nevada Las Vegas (UNLV)
文摘Exotic plant invasion is a growing concern in the conservation and management of indigenous arid land ecosystems. By creating areas of ameliorated microclimates and fertile soil below their canopies, perennial plants might influence exotic annual plant invasions. We conducted a quantitative literature review of studies that compared exotic annual plant abundance among native perennial plant species and interspace （open areas） microsites in North America＇s Mojave Desert, where exotic plant invasion has corresponded with increasing extent of wildfire and broad-scale ecosystem transformation. Ten studies compared exotic annual plant abundance between inter- spaces and below a total of 36 native perennial species. These studies revealed that： （1） With few exceptions, most native perennial species supported a greater abundance of exotic annuals than interspaces, indicating overall facilitation of exotic species by native perennials. （2） Exotic species abundance varied by orders of magnitude among native perennial species, with some perennial species harboring amounts of exotics similar to interspaces. （3） Distributions of dominant exotic species varied, where Bromus rubens displayed a greater affinity for below-perennial microsites than did Schismus spp. and Erodium cicutarium that often were most abundant in interspaces. Results suggest that the degree of facilitation of exotic plants warrants consideration when selecting native perennial species for revegetation and restoration projects.
文摘Arisaema tosaense Makino develops either 1 or 2 leaves during both the male and female phases. To clarify the relationship between growth stage (sexual stage) and leaf number in this species, we conducted morphological analysis using A. tosaense, A. japonicum Bulme, A. sikokianum French. & Sav., and A. ringens (Thunb.) Schott. We found that increase in size of pseudostem of these Arisaema species is correlated to changes in the growth stage from sterile to male and from male to female phases. In particular, 1-leaf individuals of A. tosaense appeared at the beginning of both male and female phases, suggesting that they contribute to the earlier appearance of the fertile phase from sterile
