Effects of Soil Temperature on Growth and Root Function in Rice

Abstract

The objective of this study was to clarify the effects of soil temperature in the stage from late tillering to panicle initiation (SI) and during the grain-filling stage (SII) on grain setting, dry matter production, photosynthesis, non-structural carbohydrate (NSC), xylem exudation and abscisic acid (ABA) levels in rice (Oryza sativa L. cv. Koshihikari). Rice plants were exposed to four different soil temperatures during SI or SII: 17.5, 25, 31.5 and 36.5°C (ST18, ST25, ST32 and ST37, respectively). The yield, yield components, grain filling and quality in SI were negatively influenced by high soil temperature of 37°C. On the other hand, there was no significant difference in those characters among temperature treatments in SII. The root/shoot ratio was smallest in the ST37 plants in both SI and SII, mainly due to their lighter root weight. At 7 days after initiation of treatment (DAT) in both SI and SII, the photosynthetic and xylem exudation rate tended to increase slightly as soil temperature increased up to 32°C. At 21 DAT, however, the photosynthetic rate was lowest in ST37, with concurrent decrease of diffusion conductance and SPAD value. In addition, decrease of NSC concentration in stem and xylem exudation rate, and increase of ABA level in leaves and xylem exudate were observed in ST37 plants at 21 DAT. These results suggested that high soil temperature before heading especially influenced yield, grain quality and plant growth. Possible mechanisms of the effect of soil temperature are discussed.     

Metabolie Engineering of Flower Color in Ornamental Plants

Abstract

Advances in the knowledge of plant pigment pathways at genetic, biochemical and molecular levels, and the establishment of genetic transformation methods for an increasing number of plant species have paved the way to genetic engineering of flower and plant color for ornamental purposes. From trial-and-error approaches based on the available few genes, the trend is now to comprehensively study the target species, genotypes and pigment pathways to precisely address specific breeding goals. This review examines the state of the art in this field, from the pioneering stages to fundamental and applied research on flavonoids, which is being extended to carotenoids and is also likely to involve other pigments in the near future.     

有机化合物的结构编码及在2D—QSPR研究中的应用

本文给出一种新的有机化合物的结构编码方法，此编码方法已用于我们的二维结构－性质相关性研究（2D－QSPR）中。从应用所得结果来看，这种编码方法为化学信息的处理提供了一种方便有效的工具。     

贺兰山主峰哈拉乌沟流域三水转化关系探讨

贺兰山主峰哈拉乌沟流域位于阿拉善左旗巴音浩特镇东侧,沟内1977年为旗镇建截潜流供水水源地。根据1979年~1987年实际观测沟域降水,地表水和潜流资料,研究提出三水转化参数,可为内蒙古半干旱山丘区开发利用沟谷潜水进行水资源评价参考。     

Selective Absorption of K over Na in Sugar Beet Cultivars and its Relationship with Yield and Quality in Two Contrasting Environments of Central Greece

Selective absorption (SA) of K over Na (i.e. the preferential absorption of K over Na) has been proposed as a Na tolerance mechanism but genotypic variation for this trait has not been assessed with sugar beet in the field. Thus, the aim of this study was to explore the variation of SA in 14 sugar beet cultivars and to relate SA with yield and root quality in two sites of central Greece (Amfithea and Pyrgetos). Genotypic variation for SA was significant and the SA values were higher in Pyrgetos, the site with the lower soil K and Na concentrations. In Pyrgetos, a favourable environment for sugar beet growth, cultivars yielded more and root quality was better. In that site, a negative relationship between SA and yield (fresh root weight, sugar yield) was found indicating that strong Na exclusion from root is a disadvantage for high yielding. Negative SA–yield relationships were evident in Amfithea when five cultivars with very low SA values (<1.00) were excluded from the analysis. Combined all the cultivars, curvilinear functions were the best-fitted curves for the SA–yield relationships. In Amfithea, where sugar beets had lower water content in root (WCR), a significant, positive correlation between SA and % sucrose content in fresh root weight was found. This finding was ascribed to the dilution of sucrose in roots due to the increased WCR as a result of the increased root Na concentration. In both sites, SA was positively related with root K concentration and negatively with Na concentration. The positive correlations between SA and root α-amino N concentration indicated that sugar beet N nutrition could be affected by the genotypic ability to exclude Na from the root.     

氮磷硫共掺杂生物质基多孔炭的制备及其电化学性能

为了提升农林废弃物在储能领域的高附加值利用，该研究以杉木屑为原料，磷酸三聚氰胺为磷、氮源，基于冷冻NaOH/硫脲体系溶解木质原料中纤维素，通过一步热解制备氮、磷、硫共掺杂多孔炭，并考察活化温度、NaOH/杉木屑质量比和冷冻条件对多孔炭结构及电化学性能的影响。通过X射线光电子能谱（XPS， X-ray photoelectron spectroscop ）和比表面积分析仪（BET，Brunauer-Emmett-Teller）研究多孔炭的表面结构和孔隙结构；采用循环伏安（CV，cyclic voltammetry）、恒流充放电（GCD，galvanostatic charge/discharge）和交流阻抗（EIS，electrochemical impedance spectroscopy）等测试手段表征其电化学性能。研究结果表明：随着活化温度和NaOH/杉木屑质量比的增加，多孔炭的表面积、全孔孔容和比电容呈现先增加后减小的趋势；冷冻条件和磷酸三聚氰胺的加入可以增加多孔炭的比表面积和全孔孔容，提升电化学性能。当活化温度900 ℃，NaOH/杉木屑质量比为1.2时，制备的氮、磷、硫共掺杂多孔炭的比表面积为2 048 m²/g，全孔孔容为1.655 cm³/g，介孔率为99.7%，氮、磷、硫的含量为3.41%、0.29%、1.40%。三电极体系下、6 mol/L KOH电解液中，当电流密度0.5 A/g时，比电容可达261 F/g。用NPS-900-1.2组装的对称超级电容器5 A/g电流密度条件下，比电容值为108 F/g，循环5 000次后库伦效率接近100%，电容保持率为92%。对称的超级电容器功率密度为248 W/kg时，能量密度可达17.2 Wh/kg。该研究为农林废弃物制备高性能超级电容器提供了参考依据。     

基于B/S和C/S混合模式机床产品协同设计的研究与实现

为了提高信息时代的市场快速响应能力,以数控机床为研究对象,建立了以B/S和C/S混合网络体系架构的机床产品的协同设计系统,运用COM/DCOM分布式技术、NetMeeting及Internet三维虚拟现实建模语言(VRML)构建了协同设计网络平台,重点给出了机床产品的任务分解及其实施方法.     

从英美硕士点和院系名称看图书馆的学科现状

本文介绍了美国和英国的图书馆学硕士点设置,描述了该学科在两国的院系归属情况,比较了图书馆学的不同英文名称,分析了名称不统一的原因和所反映出来的对学科的认识现状。     

关于使用 Pro/Engineer wildfire软件设计三维机械零件的几点技巧在教学中的探讨

本文对使用Pro/Engineer Wildfire 软件设计三维机械零件在教学中遇到的若干问题作了深入细致的分析,并提出了相应的解决技巧.     

TCP/IP协议脆弱性分析

TCP/IP协议是网络发展的一个基础，但是该协议确存在着致命的弱点，盲目的使用与该协议相关的服务或应用会给网络安全带来隐患，认识到TCP/IP协议的脆弱性进对我们加强网络管理和采用安全技术手段具有指导性作用。