Identification and characterization of Mini1, a gene regulating rice shoot development

The aerial parts of higher plants are generated from the shoot apical meristem （SAM）. In this study, we isolated a small rice （Oryza sativa L.） mutant that showed premature termination of shoot development and was named mini rice 1 （mini1）. The mutant was first isolated from a japonica cultivar Zhonghua11 （ZH11） subjected to ethyl methanesulfonate （EMS） treatment. With bulked segregant analysis （BSA） and mapbased cloning method, Mini1 gene was finally fine-mapped to an interval of 48.6 kb on chromosome 9. Sequence analyses revealed a single base substitution from G to A was found in the region, which resulted in an amino acid change from Gly to Asp. The candidate gene Os09go363900 was predicted to encode a putative adhesion of calyx edges protein ACE （putative HOTHEAD precursor） and genetic complementation experiment confirmed the identity of Minil. Os09go36：3900 contains glucose-methanol-choline （GMC） oxidoreductase and NAD（P）-binding Rossmann-like domain, and exhibits high similarity to Arabidopsis HOTHEAD （HTH）. Expression analysis indicated Minil was highly expressed in young shoots but lowly in roots and the expression level of most genes involved in auxin biosynthesis and signal transduction were reduced in mutant. We conclude that Mini1 plays an important role in maintaining SAM activity and promoting shoot development in rice.

Irradiance and Developmental Stages of Crown Architecture Affect Shoot Production in <i>Rhododendron reticulatum</i>

Plasticity in crown architecture, contributing to leaf arrangement within crown, is an important feature for whole plant carbon assimilation and survival. In this study, I examined the plasticity in crown architecture to light condition and developmental stage by the changes in shoot production. Rhododendron reticulatum expands crown with orthotropic growth in monopodial branching in young stage, but orthotropic growth is ceased in adult stage. Main stem of young crown is described with monopodial branching regardless of light environment. But multi-layer crown is observed in sun-lit environment rather than mono-layer crown in adult stage. Long shoot production for each branching system (foliage derived from sympodial branching) in young crown is associated with local light environment, but not in adult crown. Long shoot production rate is correlated with long shoot production rate of its mother shoot in young crown, but not in mono-layer crown. These results suggest that young crown expands branches to sun-lit position whereas adult crown reduces congestion of shoots with stochastic shoot production regardless of shoot production of mother shoots. I concluded that both light and developmental stage are important factors for shoot production and constructing crown architecture.

Erratum to “Irradiance and Developmental Stages of Crown Architecture Affect Shoot Production in <i>Rhododendron reticulatum</i>” [American Journal of Plant Sciences 4 (2013) 69-76]

The original online version of this article (Yoshimura, K. (2013) Irradiance and Developmental Stages of Crown Architecture Affect Shoot Production in Rhododendron reticulatum. American Journal of Plant Sciences, 4, 69-76. http://dx.doi.org/10.4236/ajps.2013.45A011) was published as a single-author paper mistakenly. To reflect the contribution and responsibility of the second author as well as the affiliations of the authors at the time of the study, we have revised the authorship and author affiliations of this article. The author wishes to correct the errors as: Kenichi Yoshimura1,2, Hiroaki Ishii1 1Graduate School of Science and Technology, Kobe University, Kobe, Japan 2Present Address: Center for Ecological Research, Kyoto University, Otsu, Japan Email: y.shimuken@gmail.

核桃品种试管嫩茎生根的研究

以 6个早实核桃 (JuglansregiaL .)新品种为试材 ,对长期继代培养的试管嫩茎的生根进行了研究 ,结果表明 :诱导方法、外源IBA的水平、嫩茎发育状态以及光照条件等对生根具有明显的影响。选取生长旺盛、节间较长、叶较小呈嫩黄绿色的幼态嫩茎 ,采用 2步诱导生根法 ,即黑暗条件下 ,在IBA为 5 0～ 10 0mg·L- 1 的 1 4DKW培养基中诱导 10～ 15d ,而后转移至不含IBA的DKW培养基中 ,利用这一方法顺利地诱导了嫩茎生根 ,在对 6个品种的应用中获得了 6 0 5 %～ 89 7%的生根率 ,平均根数 2 0～ 3 6。生根的嫩茎已成功地进行了下地移栽。同时就根原基诱导过程中嫩茎内源IAA和ABA水平变化进行了研究 。

籼型三系杂交水稻地上部干物质重的发育遗传研究

采用数量性状的加性-显性发育遗传模型分析了按NC Ⅱ交配设计的两套籼型三系杂交水稻地上部干物质重的发育遗传规律。结果表明,在不同发育阶段,地上部干物质重以显性效应为主,控制地上部干物质重的加性效应基因几乎不表达,而显性效应基因在两年中的表达呈连续性,且在生长中期活动强度最大,环境和基因型互作会影响地上部干物质重加性效应基因的表达,而对显性效应基因表达的影响不明显,随着发育进程的推进,地上部干物质重杂种优势趋于减弱。

籼型三系杂交水稻单茎叶干物质重的发育遗传研究

采用数量性状的加性-显性发育遗传模型,分析了按NCⅡ交配设计的两套制型三系杂交水稻单茎叶干物质重的发育遗传规律。结果表明,在不同发育阶段单茎叶干物质重以显性效应为主,控制单茎叶干物质重的加性效应基因是间断表达的,显性效应基因的表达呈连续性,加性效应和显性效应基因在单茎叶干物质重发育的全过程中是有选择地表达的,随着发育进程的推进,单茎叶干物质重杂种优势趋于减弱,不同发育阶段单茎叶干物质重与最终生物产量之间在生育前期加性相关趋于减弱,而显性相关逐渐增强,生育中期加性相关趋于稳定,而显性相关逐渐减弱,生育后期加性和显性相关均保持稳定。

Novel Insights from Live-imaging in Shoot Meristem Development

Microscopic imaging of fluorescent reporters for key meristem regulators in live tissues is emerging as a powerful technique, enabling researchers to observe dynamic spatial and temporal distribution of hormonal and developmental regulators in living cells. Aided by time-lapse microphotography, new types of imaging acquisition and analysis software, and computational modeling, we are gaining significant insights into shoot apical meristem （SAM） behavior and function. This review is focused on summarizing recent advances in the understanding of SAM organization, development, and behavior derived from live-imaging techniques. This includes the revelation of mechanical forces in microtubule-controlled anisotropic growth, the role of the CLV-WUS network in the specification of peripheral zone and central zone cells, the multiple feedback loops involving cytokinin in controlling WUS expression, auxin dynamics in determining the position of new primordia, and, finally, sequence of regulatory events leading to de novo assembly of shoots from callus in culture. Future studies toward formulating ＂digital SAM＂ that incorporates multi-dimensional data ranging from images of SAM morphogenesis to a genome-scale expression map of SAM will greatly enhance our ability to understand, predict, and manipulate SAM, containing the stem cells that give rise to all above ground parts of a plant.

我国水煮笋出口市场变化及竹笋产业发展前景

研究了2003～2011年水煮笋出口增长与出口市场结构变化,分析了竹笋产业的发展前景,并提出了开发中小径竹、强化资源培育、扶持竹笋加工业和市场网络建设等建议,以期进一步提高竹笋产业的市场竞争力。

Out of step： The function of TALE homeodomain transcription factors that regulate shoot meristem maintenance and meristem identity

The indeterminate growth pattern displayed by shoots is mediated by the proper maintenance of the shoot meristem. Meristem maintenance is dependent upon the balance of stem cell perpetuation in the central zone （CZ） and organogenesis in the peripheral zone （PZ）. Although the mechanisms that coordinate CZ and PZ function is not understood, meristem cell fate is likely achieved by the spatial interplay between gene regulatory networks and hormone signaling pathways. During shoot maturation, the identity of the shoot meristem as well as the lateral organs are transformed during the vegetative and reproductive transitions. Studies in model plant systems indicate that three amino acid extension （TALE） homeodomain proteins integrate signaling events that transform the identity of the shoot meristem and establish reproductive patterns of growth. This review will highlight the function of TALE homeodomain transcription factors that regulate shoot meristem cell fate and also function with phase specific regulators to maintain shoot meristem identity.