A new flavonoid was isolated from the bract of Zea mays L.The structure of the compound was identified as 4＇,5,7-trihydroxy-3＇,5＇-dimethoxyflavone 7-O-[β-D-apiofuranosyl（1→2）]-β-D-glucopyranoside on the ground...A new flavonoid was isolated from the bract of Zea mays L.The structure of the compound was identified as 4＇,5,7-trihydroxy-3＇,5＇-dimethoxyflavone 7-O-[β-D-apiofuranosyl（1→2）]-β-D-glucopyranoside on the ground of chemical and spectroscopic methods.展开更多
Most species in the genus Tacca （Dioscoreaceae） feature green to black purple, conspicuous inflorescence involucral bracts with variable shapes, motile filiform appendages （bracteoles）, and diverse types of inflor...Most species in the genus Tacca （Dioscoreaceae） feature green to black purple, conspicuous inflorescence involucral bracts with variable shapes, motile filiform appendages （bracteoles）, and diverse types of inflorescence morphology. To infer the evolution of these inflorescence traits, we reconstructed the molecular phylogeny of the genus, using DNA sequences from one nuclear, one mitochondrial, and three plastid loci （Internal Transcribed Spacer （ITS）, atpA, rbcL, trnL-F, and trnH-psbA）. Involucres and bracteoles characters were mapped onto the phylogeny to analyze the sequence of inflorescence trait evolution. In all analyses, species with showy involucres and bracteoles formed the most derived clade, while ancestral Tacca had small and plain involucres and short bracteoles, namely less conspicuous inflorescence structures. Two of the species with the most elaborate inflorescence morphologies （T. chantrieri in southeast China and T. integrifolia in Tibet）, are predominantly self-pollinated, indicating that these conspicuous floral displays have other functions rather than pollinator attraction. We hypothesize that the motile bracteoles and involucres may facilitate selfing; display photosynthesis in the dim understory, and protect flowers from herbivory.展开更多
Reproductive transition of grasses is characterized by switching the pattern of lateral branches,featuring the suppression of outgrowth of the subtending leaves(bracts)and rapid formation of higher-order branches in t...Reproductive transition of grasses is characterized by switching the pattern of lateral branches,featuring the suppression of outgrowth of the subtending leaves(bracts)and rapid formation of higher-order branches in the inflorescence(panicle).However,the molecular mechanisms underlying such changes remain largely unknown.Here,we show that bract suppression is required for the reproductive branching in rice.We identified a pathway involving the intrinsic time ruler microRNAI56/529,their targets SQUAMOSA PROMOTER BINDING PROTEIN LIKE(SPL)genes,NECK LEAF1(NL1),and PLASTOCHRON1(PLA1),which regulates the bract outgrowth and thus affects the pattern switch between vegetative and reproductive branching.Suppression of the bract results in global reprogramming of transcriptome and chromatin accessibility following the reproductive transition,while these processes are largely dysregu-lated in the mutants of these genes.These discoveries contribute to our understanding of the dynamic plant architecture and provide novel insights for improving crop yields.展开更多
文摘A new flavonoid was isolated from the bract of Zea mays L.The structure of the compound was identified as 4＇,5,7-trihydroxy-3＇,5＇-dimethoxyflavone 7-O-[β-D-apiofuranosyl（1→2）]-β-D-glucopyranoside on the ground of chemical and spectroscopic methods.
基金funded by the Key Project of the Chinese Academy of Science (KSCX2-YW-Z-0904)National Natural Science Foundation of China (30670131)+1 种基金Yunnan Provincial Natural Science Foundation (2006C0055M)to Ling ZhangLaboratory equipment for phylogenetic analyses was provided by the State Key Basic Research and Development Plan of China (973, 2008GA001) to De-Zhu Li
文摘Most species in the genus Tacca （Dioscoreaceae） feature green to black purple, conspicuous inflorescence involucral bracts with variable shapes, motile filiform appendages （bracteoles）, and diverse types of inflorescence morphology. To infer the evolution of these inflorescence traits, we reconstructed the molecular phylogeny of the genus, using DNA sequences from one nuclear, one mitochondrial, and three plastid loci （Internal Transcribed Spacer （ITS）, atpA, rbcL, trnL-F, and trnH-psbA）. Involucres and bracteoles characters were mapped onto the phylogeny to analyze the sequence of inflorescence trait evolution. In all analyses, species with showy involucres and bracteoles formed the most derived clade, while ancestral Tacca had small and plain involucres and short bracteoles, namely less conspicuous inflorescence structures. Two of the species with the most elaborate inflorescence morphologies （T. chantrieri in southeast China and T. integrifolia in Tibet）, are predominantly self-pollinated, indicating that these conspicuous floral displays have other functions rather than pollinator attraction. We hypothesize that the motile bracteoles and involucres may facilitate selfing; display photosynthesis in the dim understory, and protect flowers from herbivory.
基金the National Key Research and Development Program of China(2016YFD0100903)the National Natural Science Foundation of China(31600983 and 31821005)+1 种基金the China Postdoctoral Science Foundation(2017T100564 and 2016M590699)the Earmarked Fund for the China Agricultural Research System(CARS-01-05).
文摘Reproductive transition of grasses is characterized by switching the pattern of lateral branches,featuring the suppression of outgrowth of the subtending leaves(bracts)and rapid formation of higher-order branches in the inflorescence(panicle).However,the molecular mechanisms underlying such changes remain largely unknown.Here,we show that bract suppression is required for the reproductive branching in rice.We identified a pathway involving the intrinsic time ruler microRNAI56/529,their targets SQUAMOSA PROMOTER BINDING PROTEIN LIKE(SPL)genes,NECK LEAF1(NL1),and PLASTOCHRON1(PLA1),which regulates the bract outgrowth and thus affects the pattern switch between vegetative and reproductive branching.Suppression of the bract results in global reprogramming of transcriptome and chromatin accessibility following the reproductive transition,while these processes are largely dysregu-lated in the mutants of these genes.These discoveries contribute to our understanding of the dynamic plant architecture and provide novel insights for improving crop yields.
