以超级杂交稻“两优培九”及其父本“9311”、母本“培矮64S”和三系杂交稻组合“汕优63”为研究材料，采用^14C同位素示踪等技术，研究了“两优培九”剑叶叶鞘的光合能力与叶鞘光合产物的分配。结果表明，两优培九剑叶叶鞘的净光合速...以超级杂交稻“两优培九”及其父本“9311”、母本“培矮64S”和三系杂交稻组合“汕优63”为研究材料，采用^14C同位素示踪等技术，研究了“两优培九”剑叶叶鞘的光合能力与叶鞘光合产物的分配。结果表明，两优培九剑叶叶鞘的净光合速率均值比汕优63高0．10μmol CO2 m^-2s^-2，尤以第3期，即灌浆关键时期，极显著高于汕优63，其他时期差异不显著；其叶鞘叶绿素含量的均值比汕优63高2．36SPAD值，各期均高于汕优63，其中，第1、3期显著高于汕优63；其剑叶叶鞘的Rubisco初始活性和总活性与汕优63差异不显著，但Rubisco活化率均值比汕优63高1．52％，具有平均优势，其中第3期显著高于汕优63；其叶鞘光合产物输送到穗部的量即转化为经济产量的量比汕优63高；与父母本相比，其剑叶叶鞘光合能力的均值具有平均优势或超亲优势；水稻叶鞘完全具有同叶片一样的光合能力，只有值的大小差异；水稻叶鞘的光合产物对产量的贡献一般为10％～20％。两优培九叶鞘及叶片光合功能都较强是其具有超高产特性的一个重要原因。展开更多
Phloem-feeding insects cause massive losses in agriculture and horticulture.Host plant resistance to phloem-feeding insects is often mediated by changes in phloem composition,which deter insect settling and feeding an...Phloem-feeding insects cause massive losses in agriculture and horticulture.Host plant resistance to phloem-feeding insects is often mediated by changes in phloem composition,which deter insect settling and feeding and decrease viability.Here,we report that rice plant resistance to the phloem-feeding brown planthopper(BPH)is associated with fortification of the sclerenchyma tissue,which is located just beneath the epidermis and a cell layer or two away from the vascular bundle in the rice leaf sheath.We found that BPHs prefer to feed on the smooth and soft region on the surface of rice leaf sheaths called the long-cell block.We identified Bph30 as a rice BPH resistance gene that prevents BPH stylets from reaching the phloem due to the fortified sclerenchyma.Bph30 is strongly expressed in sclerenchyma cells and enhances cellulose and hemicellulose synthesis,making the cell walls stiffer and sclerenchyma thicker.The structurally fortified sclerenchyma is a formidable barrier preventing BPH stylets from penetrating the leaf sheath tissues and arriving at the phloem to feed.Bph30 belongs to a novel gene family,encoding a protein with two leucine-rich domains.Another member of the family,Bph40,also conferred resistance to BPH.Collectively,the fortified sclerenchyma-mediated resistance mechanism revealed in this study expands our understanding of plant-insect interactions and opens a new path for controlling planthoppers in rice.展开更多
The aim of this study is to investigate the effect of chemical extraction method on the properties of doum palm fibres. The method of extraction which is carried out is a soda treatment. First, an investigation of the...The aim of this study is to investigate the effect of chemical extraction method on the properties of doum palm fibres. The method of extraction which is carried out is a soda treatment. First, an investigation of the extraction processes was undertaken. Secondly, the physical properties (surface morphology, density, linear density and diameter), the mechanical properties (tenacity, strain) and chemical properties (FT-IR spectra) of doum palm fibres were inspected. Finally, a comparison between properties of doum palm fibres and other vegetal ones has been included. Results indicates an influence of soda treatment on properties of Doum palm fibers. In fact, there is an improvement on fibers diameter and linear density while increasing soda concentration, temperature and treatment duration. Moreover, the studied fibers have a low density which does not exceed 1. The fibers tenacity achieved the maximum value of 20.86 cN/Tex when precessing in the following combination (0.75 N, 100°C and 180 mn). In the end, the FTIR spectra reveals a change in structure after this alkali treatment while increasing the cellulose amount exposed on the fiber surface and consequently the number of possible reaction sites (OH groups).展开更多
The development of a plant leaf is a meticulously orchestrated sequence of events producing a complex organ comprising diverse cell types. The reticulate class of leaf variegation mutants displays contrasting pigmenta...The development of a plant leaf is a meticulously orchestrated sequence of events producing a complex organ comprising diverse cell types. The reticulate class of leaf variegation mutants displays contrasting pigmentation between veins and interveinal regions due to specific aberrations in the development of mesophyll cells. Thus, the reticulate mutants offer a potent tool to investigate cell-type-specific developmental processes. The discovery that most mutants are affected in plastid-localized, metabolic pathways that are strongly expressed in vasculature-associated tis- sues implicates a crucial role for the bundle sheath and their chloroplasts in proper development of the mesophyll cells. Here, we review the reticulate mutants and their phenotypic characteristics, with a focus on those in Arabidopsis thali- ana. Two alternative models have been put forward to explain the relationship between plastid metabolism and meso- phyll cell development, which we call here the supply and the signaling hypotheses. We critically assess these proposed models and discuss their implications for leaf development and bundle sheath function in C3 species. The characteriza- tion of the reticulate mutants supports the significance of plastid retrograde signaling in cell development and highlights the significance of the bundle sheath in C3 photosynthesis.展开更多
文摘以超级杂交稻“两优培九”及其父本“9311”、母本“培矮64S”和三系杂交稻组合“汕优63”为研究材料，采用^14C同位素示踪等技术，研究了“两优培九”剑叶叶鞘的光合能力与叶鞘光合产物的分配。结果表明，两优培九剑叶叶鞘的净光合速率均值比汕优63高0．10μmol CO2 m^-2s^-2，尤以第3期，即灌浆关键时期，极显著高于汕优63，其他时期差异不显著；其叶鞘叶绿素含量的均值比汕优63高2．36SPAD值，各期均高于汕优63，其中，第1、3期显著高于汕优63；其剑叶叶鞘的Rubisco初始活性和总活性与汕优63差异不显著，但Rubisco活化率均值比汕优63高1．52％，具有平均优势，其中第3期显著高于汕优63；其叶鞘光合产物输送到穗部的量即转化为经济产量的量比汕优63高；与父母本相比，其剑叶叶鞘光合能力的均值具有平均优势或超亲优势；水稻叶鞘完全具有同叶片一样的光合能力，只有值的大小差异；水稻叶鞘的光合产物对产量的贡献一般为10％～20％。两优培九叶鞘及叶片光合功能都较强是其具有超高产特性的一个重要原因。
基金This work was supported by the Major Program of Guangdong Basic andApplied Research,China(2019B030302006)the National Program onResearch and Development of Transgenic Plants of China(2016ZX08009-003)+1 种基金grants from the National Natural Science Foundationof China(31630063)the National Key Research and DevelopmentProgram of China(2016YFD0100600 and 2016YFD0100900).
文摘Phloem-feeding insects cause massive losses in agriculture and horticulture.Host plant resistance to phloem-feeding insects is often mediated by changes in phloem composition,which deter insect settling and feeding and decrease viability.Here,we report that rice plant resistance to the phloem-feeding brown planthopper(BPH)is associated with fortification of the sclerenchyma tissue,which is located just beneath the epidermis and a cell layer or two away from the vascular bundle in the rice leaf sheath.We found that BPHs prefer to feed on the smooth and soft region on the surface of rice leaf sheaths called the long-cell block.We identified Bph30 as a rice BPH resistance gene that prevents BPH stylets from reaching the phloem due to the fortified sclerenchyma.Bph30 is strongly expressed in sclerenchyma cells and enhances cellulose and hemicellulose synthesis,making the cell walls stiffer and sclerenchyma thicker.The structurally fortified sclerenchyma is a formidable barrier preventing BPH stylets from penetrating the leaf sheath tissues and arriving at the phloem to feed.Bph30 belongs to a novel gene family,encoding a protein with two leucine-rich domains.Another member of the family,Bph40,also conferred resistance to BPH.Collectively,the fortified sclerenchyma-mediated resistance mechanism revealed in this study expands our understanding of plant-insect interactions and opens a new path for controlling planthoppers in rice.
文摘The aim of this study is to investigate the effect of chemical extraction method on the properties of doum palm fibres. The method of extraction which is carried out is a soda treatment. First, an investigation of the extraction processes was undertaken. Secondly, the physical properties (surface morphology, density, linear density and diameter), the mechanical properties (tenacity, strain) and chemical properties (FT-IR spectra) of doum palm fibres were inspected. Finally, a comparison between properties of doum palm fibres and other vegetal ones has been included. Results indicates an influence of soda treatment on properties of Doum palm fibers. In fact, there is an improvement on fibers diameter and linear density while increasing soda concentration, temperature and treatment duration. Moreover, the studied fibers have a low density which does not exceed 1. The fibers tenacity achieved the maximum value of 20.86 cN/Tex when precessing in the following combination (0.75 N, 100°C and 180 mn). In the end, the FTIR spectra reveals a change in structure after this alkali treatment while increasing the cellulose amount exposed on the fiber surface and consequently the number of possible reaction sites (OH groups).
文摘The development of a plant leaf is a meticulously orchestrated sequence of events producing a complex organ comprising diverse cell types. The reticulate class of leaf variegation mutants displays contrasting pigmentation between veins and interveinal regions due to specific aberrations in the development of mesophyll cells. Thus, the reticulate mutants offer a potent tool to investigate cell-type-specific developmental processes. The discovery that most mutants are affected in plastid-localized, metabolic pathways that are strongly expressed in vasculature-associated tis- sues implicates a crucial role for the bundle sheath and their chloroplasts in proper development of the mesophyll cells. Here, we review the reticulate mutants and their phenotypic characteristics, with a focus on those in Arabidopsis thali- ana. Two alternative models have been put forward to explain the relationship between plastid metabolism and meso- phyll cell development, which we call here the supply and the signaling hypotheses. We critically assess these proposed models and discuss their implications for leaf development and bundle sheath function in C3 species. The characteriza- tion of the reticulate mutants supports the significance of plastid retrograde signaling in cell development and highlights the significance of the bundle sheath in C3 photosynthesis.
