Rice florets are subtended by two sterile lemmas,whose origin and biological functions have not been studied extensively.Here we demonstrate that two putative transcription factors,LAX PANICLE1(LAX1)and FRIZZY PANICLE...Rice florets are subtended by two sterile lemmas,whose origin and biological functions have not been studied extensively.Here we demonstrate that two putative transcription factors,LAX PANICLE1(LAX1)and FRIZZY PANICLE(FZP),synergistically control the development of sterile lemmas.Both LAX1 and FZP are previously known for their roles in panicle and floret development.Disruption of either LAX1 or FZP greatly reduces the number of floret development.We generated new lax1 mutants(lax1-c)using CRISPR/Cas9 gene editing technology.In addition to the expected lax panicle phenotypes,we noticed that a significant number of spikelets of lax1-c developed elongated sterile lemmas.Moreover,our characterization of lax1-RNAi plants also revealed sterile lemma phenotypes similar to lax1-c mutants.We isolated a weak allele of fzp(fzp-14)in a genetic screen for lax1–1 enhancers.The fzp-14 lax1–1 double mutants completely eliminated flower development.Interestingly,the isolated fzp-14 produced spikelets with elongated sterile lemmas.Furthermore,fzp-14 was haploid-insufficient in the lax1–1 background whereas fzp-14 heterozygous plants were indistinguishable from wild type plants.The lax1–1 fzp-14+/−also developed elongated sterile lemma as observed in lax1-c,lax1-RNAi,and fzp-14,suggesting that LAX1 and FZP synergistically control sterile lemma development.展开更多
基于标准BS EN 1993-1-9-2005的要求,文章介绍了城轨车辆车体结构疲劳寿命分析的步骤,运用有限元分析法模拟计算不同疲劳载荷工况下车体结构的最大应力范围,并进行规定循环次数下的疲劳评估。结果表明:结构疲劳寿命满足置信度为95%条件...基于标准BS EN 1993-1-9-2005的要求,文章介绍了城轨车辆车体结构疲劳寿命分析的步骤,运用有限元分析法模拟计算不同疲劳载荷工况下车体结构的最大应力范围,并进行规定循环次数下的疲劳评估。结果表明:结构疲劳寿命满足置信度为95%条件下的预期要求;同种工况下,焊缝处所产生的最大应力更逼近疲劳强度允许值;应力分布与结构设计密切相关,通过改进结构以增加结构疲劳寿命的理念是可行且有效的。展开更多
基金supported by the National Transgenic Research Program of China(2016ZX08010002)
文摘Rice florets are subtended by two sterile lemmas,whose origin and biological functions have not been studied extensively.Here we demonstrate that two putative transcription factors,LAX PANICLE1(LAX1)and FRIZZY PANICLE(FZP),synergistically control the development of sterile lemmas.Both LAX1 and FZP are previously known for their roles in panicle and floret development.Disruption of either LAX1 or FZP greatly reduces the number of floret development.We generated new lax1 mutants(lax1-c)using CRISPR/Cas9 gene editing technology.In addition to the expected lax panicle phenotypes,we noticed that a significant number of spikelets of lax1-c developed elongated sterile lemmas.Moreover,our characterization of lax1-RNAi plants also revealed sterile lemma phenotypes similar to lax1-c mutants.We isolated a weak allele of fzp(fzp-14)in a genetic screen for lax1–1 enhancers.The fzp-14 lax1–1 double mutants completely eliminated flower development.Interestingly,the isolated fzp-14 produced spikelets with elongated sterile lemmas.Furthermore,fzp-14 was haploid-insufficient in the lax1–1 background whereas fzp-14 heterozygous plants were indistinguishable from wild type plants.The lax1–1 fzp-14+/−also developed elongated sterile lemma as observed in lax1-c,lax1-RNAi,and fzp-14,suggesting that LAX1 and FZP synergistically control sterile lemma development.
文摘基于标准BS EN 1993-1-9-2005的要求,文章介绍了城轨车辆车体结构疲劳寿命分析的步骤,运用有限元分析法模拟计算不同疲劳载荷工况下车体结构的最大应力范围,并进行规定循环次数下的疲劳评估。结果表明:结构疲劳寿命满足置信度为95%条件下的预期要求;同种工况下,焊缝处所产生的最大应力更逼近疲劳强度允许值;应力分布与结构设计密切相关,通过改进结构以增加结构疲劳寿命的理念是可行且有效的。
