Twelve genes of the PIN family in rice were analyzed for gene and protein structures and an evolutionary relationship with reported AtPINs in Arabidopsis. Four members of PIN1 （designated as OsPINla-d）, one gene pai...Twelve genes of the PIN family in rice were analyzed for gene and protein structures and an evolutionary relationship with reported AtPINs in Arabidopsis. Four members of PIN1 （designated as OsPINla-d）, one gene paired with AtPIN2 （OsPIN2）, three members of PIN5 （OsPIN5a-c）, one gene paired with AtPIN8 （OsPIN8）, and three monocot-specific PINs （OsPIN9, OsPINIOa, and b） were identified from the phylogenetic analysis. Tissue-specific expression patterns of nine PIN genes among them were investigated using RT-PCR and GUS reporter. The wide variations in the expression domain in different tissues of the PIN genes were observed. In general, PIN genes are up-regulated by exogenous auxin, while different responses of different PIN genes to other hormones were found.展开更多
Polar transport of the phytohormone auxin and the establishment of localized auxin maxima regulate em- bryonic development, stem cell maintenance, root and shoot architecture, and tropic growth responses. The past dec...Polar transport of the phytohormone auxin and the establishment of localized auxin maxima regulate em- bryonic development, stem cell maintenance, root and shoot architecture, and tropic growth responses. The past decade has been marked by dramatic progress in efforts to elucidate the complex mechanisms by which auxin transport regulates plant growth. As the understanding of auxin transport regulation has been increasingly elaborated, it has become clear that this process is involved in almost all plant growth and environmental responses in some way. However, we still lack information about some basic aspects of this fundamental regulatory mechanism. In this review, we present what we know （or what we think we know） and what we do not know about seven auxin-regulated processes. We discuss the role of auxin transport in gravitropism in primary and lateral roots, phototropism, shoot branching, leaf expansion, and venation. We also discuss the auxin reflux/fountain model at the root tip, flavonoid modulation of auxin transport processes, and outstanding aspects of post-translational regulation of auxin transporters. This discussion is not meant to be exhaustive, but highlights areas in which generally held assumptions require more substantive validation.展开更多
According to differential geometry and gear geometry, the equation of meshing for small teeth difference planetary gearing and a universal equation of conjugated profile are established based on cylindrical pin tooth ...According to differential geometry and gear geometry, the equation of meshing for small teeth difference planetary gearing and a universal equation of conjugated profile are established based on cylindrical pin tooth and given motion. The correct meshing condition, contact line, contact ratio, calculating method for pin tooth's maximum contact point are developed. Investigation on the theory of conjugated meshing is carried out when the tooth difference numbers between pin wheel and cycloidal gear are 1, 2, 3 and ?1, respectively. A general method called enveloping method to generate hypocycloid and epicycloid is put forward. The correct meshing condition for cycloid pin wheel gearing is provided, and the contact line and the contact ratio are also discussed.展开更多
文摘Twelve genes of the PIN family in rice were analyzed for gene and protein structures and an evolutionary relationship with reported AtPINs in Arabidopsis. Four members of PIN1 （designated as OsPINla-d）, one gene paired with AtPIN2 （OsPIN2）, three members of PIN5 （OsPIN5a-c）, one gene paired with AtPIN8 （OsPIN8）, and three monocot-specific PINs （OsPIN9, OsPINIOa, and b） were identified from the phylogenetic analysis. Tissue-specific expression patterns of nine PIN genes among them were investigated using RT-PCR and GUS reporter. The wide variations in the expression domain in different tissues of the PIN genes were observed. In general, PIN genes are up-regulated by exogenous auxin, while different responses of different PIN genes to other hormones were found.
基金This work was funded by the National Science Foundation，A.S.M.and Purdue Agriculture Research Foundation grant to W.A.P
文摘Polar transport of the phytohormone auxin and the establishment of localized auxin maxima regulate em- bryonic development, stem cell maintenance, root and shoot architecture, and tropic growth responses. The past decade has been marked by dramatic progress in efforts to elucidate the complex mechanisms by which auxin transport regulates plant growth. As the understanding of auxin transport regulation has been increasingly elaborated, it has become clear that this process is involved in almost all plant growth and environmental responses in some way. However, we still lack information about some basic aspects of this fundamental regulatory mechanism. In this review, we present what we know （or what we think we know） and what we do not know about seven auxin-regulated processes. We discuss the role of auxin transport in gravitropism in primary and lateral roots, phototropism, shoot branching, leaf expansion, and venation. We also discuss the auxin reflux/fountain model at the root tip, flavonoid modulation of auxin transport processes, and outstanding aspects of post-translational regulation of auxin transporters. This discussion is not meant to be exhaustive, but highlights areas in which generally held assumptions require more substantive validation.
基金the National Science and Technology Supporting Program (Grant No. No. 2006BAF01B08)Chongqing Science and Technology Key Task (Grant No. CSCT2006AA3010-6)
文摘According to differential geometry and gear geometry, the equation of meshing for small teeth difference planetary gearing and a universal equation of conjugated profile are established based on cylindrical pin tooth and given motion. The correct meshing condition, contact line, contact ratio, calculating method for pin tooth's maximum contact point are developed. Investigation on the theory of conjugated meshing is carried out when the tooth difference numbers between pin wheel and cycloidal gear are 1, 2, 3 and ?1, respectively. A general method called enveloping method to generate hypocycloid and epicycloid is put forward. The correct meshing condition for cycloid pin wheel gearing is provided, and the contact line and the contact ratio are also discussed.
