In deep underground engineering construction,the dominant rock failure mode,whether by tension or shear,influences the engineering instability.Therefore,the critical triggering conditions that induce shear or tensile ...In deep underground engineering construction,the dominant rock failure mode,whether by tension or shear,influences the engineering instability.Therefore,the critical triggering conditions that induce shear or tensile fractures in rocks urgently need further investigation.This paper designs direct shear tests on intact limestone under different normal stress conditions,using binarization methods supplemented by scanning electron microscopy to explore the two-dimensional fracture damage characteristics of limestone joint surfaces.Based on the three-dimensional morphological characteristics of limestone joint surfaces,a method for automatically identifying the three-dimensional curvature of rock joint surfaces is proposed,quantifying the changes in curvature distribution under different normal stresses.Further analysis focused on the proportion of shear damage and high-curvature areas on the upper and lower joint surfaces of limestone.The study examined changes in the cumulative energy of pre-peak acoustic emission and damage under varying effective normal stress-to-shear stress ratios.These results were used to identify and validate the critical threshold range for inducing shear fractures in limestone.The conclusions indicate that the proportion of shear damage area of limestone joint surfaces is positively correlated with effective normal stress.The proportion of high curvature of limestone joint surfaces decreases with increasing normal stress.Both the rapid growth stage of shear damage area and the rapid descent stage of high curvature proportion occur in the effective normal stress to shear stress ratio range of[1.4,1.6].The cumulative energy of pre-peak acoustic emission and damage under different effective normal stress to shear stress ratios increase sharply around the ratio of 1.6,further verifying that the effective normal stress to shear stress ratio range of[1.4,1.6]is the critical threshold range for inducing shear fractures in limestone.展开更多
The trichomes of rice leaves are formed by the differentiation and development of epidermal cells.Plant trichomes play an important role in stress resistance and protection against direct ultraviolet irradiation.Howev...The trichomes of rice leaves are formed by the differentiation and development of epidermal cells.Plant trichomes play an important role in stress resistance and protection against direct ultraviolet irradiation.However,the development of rice trichomes remains poorly understood.In this study,we conducted ethylmethane sulfonate(EMS)-mediated mutagenesis on the wild-type(WT)indica rice‘Xida 1B’.Phenotypic analysis led to the screening of a mutant that is defective in trichome development,designated lhl1(less hairy leaf 1).We performed map-based cloning and localized the mutated gene to the 70-kb interval between the molecular markers V-9 and V-10 on chromosome 2.The locus LOC_Os02g25230 was identified as the candidate gene by sequencing.We constructed RNA interference(LHL1-RNAi)and overexpression lines(LHL1-OE)to verity the candidate gene.The leaves of the LHL1-RNAi lines showed the same trichome developmental defects as the lhl1 mutant,whereas the trichome morphology on the leaf surface of the LHL1-OE lines was similar to that of the WT,although the number of trichomes was significantly higher.Quantitative real-time PCR(RT-qPCR)analysis revealed that the expression levels of auxin-related genes and positive regulators of trichome development in the lhl1 mutant were down-regulated compared with the WT.Hormone response analysis revealed that LHL1 expression was affected by auxin.The results indicate that the influence of LHL1 on trichome development in rice leaves may be associated with an auxin pathway.展开更多
全面了解植物水分利用效率(WUE)研究现状可为未来该领域研究方向的确立和发展趋势预测提供依据。为此,基于Web of Science(WoS)核心合集的科学引文索引数据库,采用VOSviewer文献计量分析软件对植物WUE研究2000-2021年发表的相关文献进...全面了解植物水分利用效率(WUE)研究现状可为未来该领域研究方向的确立和发展趋势预测提供依据。为此,基于Web of Science(WoS)核心合集的科学引文索引数据库,采用VOSviewer文献计量分析软件对植物WUE研究2000-2021年发表的相关文献进行分析。结果表明,1)2000-2021年世界范围内该领域发文数量呈抛物线式增长趋势,载文量较多的期刊有Agricultural Water Management,Field Crops Research,Agricultural and Forest Meteorology等,发文量前3的国家为中国、美国和澳大利亚,发文量前3的机构为中国科学院、西北农林科技大学和中国农业大学,发文量前3的作者为Liu Fulai,Kang Shaozhong,H.Medrano,该领域大多数研究者之间合作关系较少;2)尽管中国学者发文数量最多,但有影响力和高被引用论文数量少;3)目前该领域主要的研究方向可分为3类,植物WUE种间或种内差异的生理或分子机制、灌溉和施肥等田间管理措施对作物WUE的影响与调控、气候变化对陆地生态系统WUE的影响;4)基于关键词热点分析和热点论文分析,给出了未来植物WUE研究需要加强的方面。展开更多
基金Projects(52004147,51974173)supported by the National Natural Science Foundation of ChinaProject(GJNY-20-113-19)supported by the Open Fund of State Key Laboratory of Water Resource Protection and Utilization in Coal Mining,China。
文摘In deep underground engineering construction,the dominant rock failure mode,whether by tension or shear,influences the engineering instability.Therefore,the critical triggering conditions that induce shear or tensile fractures in rocks urgently need further investigation.This paper designs direct shear tests on intact limestone under different normal stress conditions,using binarization methods supplemented by scanning electron microscopy to explore the two-dimensional fracture damage characteristics of limestone joint surfaces.Based on the three-dimensional morphological characteristics of limestone joint surfaces,a method for automatically identifying the three-dimensional curvature of rock joint surfaces is proposed,quantifying the changes in curvature distribution under different normal stresses.Further analysis focused on the proportion of shear damage and high-curvature areas on the upper and lower joint surfaces of limestone.The study examined changes in the cumulative energy of pre-peak acoustic emission and damage under varying effective normal stress-to-shear stress ratios.These results were used to identify and validate the critical threshold range for inducing shear fractures in limestone.The conclusions indicate that the proportion of shear damage area of limestone joint surfaces is positively correlated with effective normal stress.The proportion of high curvature of limestone joint surfaces decreases with increasing normal stress.Both the rapid growth stage of shear damage area and the rapid descent stage of high curvature proportion occur in the effective normal stress to shear stress ratio range of[1.4,1.6].The cumulative energy of pre-peak acoustic emission and damage under different effective normal stress to shear stress ratios increase sharply around the ratio of 1.6,further verifying that the effective normal stress to shear stress ratio range of[1.4,1.6]is the critical threshold range for inducing shear fractures in limestone.
基金supported by grants from the Natural Science Foundation of Chongqing,China(cstc2020jcyj-msxm0539,cstc2015jcyjA80008)the National College Students Innovation and Entrepreneurship Training Program from the Ministry of Education,China(202110635082)the National Natural Science Foundation of China(32171964,31171178).
文摘The trichomes of rice leaves are formed by the differentiation and development of epidermal cells.Plant trichomes play an important role in stress resistance and protection against direct ultraviolet irradiation.However,the development of rice trichomes remains poorly understood.In this study,we conducted ethylmethane sulfonate(EMS)-mediated mutagenesis on the wild-type(WT)indica rice‘Xida 1B’.Phenotypic analysis led to the screening of a mutant that is defective in trichome development,designated lhl1(less hairy leaf 1).We performed map-based cloning and localized the mutated gene to the 70-kb interval between the molecular markers V-9 and V-10 on chromosome 2.The locus LOC_Os02g25230 was identified as the candidate gene by sequencing.We constructed RNA interference(LHL1-RNAi)and overexpression lines(LHL1-OE)to verity the candidate gene.The leaves of the LHL1-RNAi lines showed the same trichome developmental defects as the lhl1 mutant,whereas the trichome morphology on the leaf surface of the LHL1-OE lines was similar to that of the WT,although the number of trichomes was significantly higher.Quantitative real-time PCR(RT-qPCR)analysis revealed that the expression levels of auxin-related genes and positive regulators of trichome development in the lhl1 mutant were down-regulated compared with the WT.Hormone response analysis revealed that LHL1 expression was affected by auxin.The results indicate that the influence of LHL1 on trichome development in rice leaves may be associated with an auxin pathway.
文摘全面了解植物水分利用效率(WUE)研究现状可为未来该领域研究方向的确立和发展趋势预测提供依据。为此,基于Web of Science(WoS)核心合集的科学引文索引数据库,采用VOSviewer文献计量分析软件对植物WUE研究2000-2021年发表的相关文献进行分析。结果表明,1)2000-2021年世界范围内该领域发文数量呈抛物线式增长趋势,载文量较多的期刊有Agricultural Water Management,Field Crops Research,Agricultural and Forest Meteorology等,发文量前3的国家为中国、美国和澳大利亚,发文量前3的机构为中国科学院、西北农林科技大学和中国农业大学,发文量前3的作者为Liu Fulai,Kang Shaozhong,H.Medrano,该领域大多数研究者之间合作关系较少;2)尽管中国学者发文数量最多,但有影响力和高被引用论文数量少;3)目前该领域主要的研究方向可分为3类,植物WUE种间或种内差异的生理或分子机制、灌溉和施肥等田间管理措施对作物WUE的影响与调控、气候变化对陆地生态系统WUE的影响;4)基于关键词热点分析和热点论文分析,给出了未来植物WUE研究需要加强的方面。
