Interspecific relationships of Lycoris (Amaryllidaceae) inferred from inter-simple sequence repeat data

Inter-simple sequence repeat (ISSR) markers were used to evaluate interspecific relationships of Lycoris. Twenty-four samples were included in the study representing a total of 20 among species and varieties. Thirteen primers produced 228 discernible DNA fragments, 205, or 89.91%, of which were polymorphic, indicating a high level of interspecific genetic variation in Lycoris. Our UPGMA cluster analysis recognized four major groups of species, which were consistent with morphological and karyotype observations. The first group included species with telocentric and metacentric chromosomes, while the second consisted of species with a haploid genome of 11 subtelocentric chromosomes. The third group contained species with a mixture of subtelocentric, telocentric and metacentric chromosomes. The last group included the Japanese and Korean species. Lycoris anhuiensis was clustered within accessions of Lycoris longituba, suggesting that it could be recognized as a variety of L. longituba. Our ISSR data also suggested that L. straminea may be a hybrid between Lycoris chinensis and Lycoris radiata var. pumila, and that L. caldwellii, an allotriploid, may be of a hybrid origin of L. chinensis and L. sprengeri.     

第8届国际甜椒圃地试验报告

从6个方面对参试品种进行了比较分析,结论认为：除ISPN8#3在陕西岐山试验地表现差以外,其余品种（系）均表现优良。     

低温胁迫对高粱幼苗MDA含量、SOD和POD活性的影响

为了探明高粱幼苗耐冷生理机制,以高粱耐冷和冷敏材料幼苗为试验材料,利用智能光照培养箱设置低温条件,分析了低温和常温条件下高粱耐冷和冷敏材料的丙二醛(MDA)含量、超氧化物岐化酶(SOD)活性和过氧化物酶(POD)活性。结果表明,低温胁迫后,两类材料的MDA含量、SOD活性、POD活性都出现了增高的趋势,耐冷材料MDA含量的增加幅度低于冷敏材料,耐冷材料的SOD活性、POD活性的增加幅度则显著高于冷敏材料,说明材料的耐冷与否,与低温胁迫后MDA含量、SOD活性、POD活性的增加量有关,MDA含量的增加幅度愈小材料愈耐冷,SOD活性、POD活性的增加幅度愈大材料愈耐冷。     

小麦纹枯病和白粉病双抗抗源的初步鉴定

“七五”和“八五”期间,进行了大量的小麦常规品种(系)之间,以及与近缘物种的杂交工作,从某些杂种后代中,筛选出几百份抗白粉病优良选系。为了创造兼抗纹枯病和白粉病的双抗抗源,于1997 年春整理部分优良选系、地方品种和国外引进品种(系),共182 份小麦材料进行的纹枯病抗性和白粉病抗性鉴定,对部分抗性材料于当年秋在温室接种情况下继续进行抗性鉴定。初步鉴定结果表明:有27 份材料与对照材料相比纹枯病病情指数较低,显示了较强的抗(耐)纹枯病能力;其中有16 份材料表现出兼抗纹枯病和白粉病。另外,对部分小麦的近缘物种的初步鉴定发现球茎大麦、多花黑麦草和黑麦等对白粉病和纹枯病有很强的抗性。     

蓼科杀虫植物——辣蓼

论述了辣蓼(Polygonum hydropiper L.)的分布、毒性、药用性、化学成分及其对昆虫的生物活性;并对辣蓼在植物源农药应用方面存在的问题及发展前景进行了一些探讨.     

不同湍流模型在轴流泵性能预测中的应用

为了评价不同湍流模型在轴流泵性能预测中的精度,该文以南水北调工程轴流泵模型作为研究对象,分别选取了3种湍流模型标准k-ε湍流模型(standard k-ε)、重正化群k-ε湍流模型(renormalization group k-ε,RNG)和雷诺应力模型(reynolds stress model,RSM),基于SIMPLE算法(semi-implicit method for pressure-linked equations)和结构化网格,进行了轴流泵性能预测和全流场数值模拟,并以水利部天津同台测试的试验结果作为基准对预测扬程和效率进行了误差分析。研究结果表明,网格密度对模拟结果具有较大影响,较疏的网格导致性能预测精度降低,在大流量和小流量工况下预测的扬程和效率误差将达到3%以上;在最优工况下,Standard k-ε、RNG k-ε和RSM湍流模型的扬程预测误差分别为0.97%、1.12%和1.24%,效率预测误差分别为2.93%、2.49%和2.97%,可满足工程应用要求;但在非设计工况下,由于二次回流、空化等复杂流动的存在,内部流场复杂,3种湍流模型的扬程最大预测误差范围为9.40%～14.30%,效率最大预测误差范围为4.48%～8.30%。该结论将为轴流泵性能预测的可靠性提供依据。     

Changes in soil macropores: Superposition of the roles of organic nutrient amendments and the greenhouse pattern in vegetable plantations

Organic farming can potentially mitigate soil compaction, which commonly occurs in vegetable plantations, particularly in greenhouses when compared with open‐air systems. Although several studies have addressed the effect of planting patterns on soil pore characteristics, few studies have focused on changes in pore attributes under organic fertilization. We used adjacent fields during green manure planting as a control to compare the differences in soil physicochemical and macropore parameters between 14‐year‐old greenhouse plots and open‐air plots under organic fertilization. Pearson's correlation analysis was performed to analyse the drivers of soil macropore characteristics in vegetable plantations in Jiangsu Province, China. A significant increase in connectivity, fractal dimensions and total macroporosity and a decrease in bulk density after 14 years of organic farming, particularly in the surface layer in the greenhouse, were observed. However, the difference in pores in the plough pan layer was not significant between the treatments. The volume of small pores (50–500 μm) and medium pores (500–1,000 μm) increased significantly (p < 0.05) in both the greenhouse and open‐air systems, showing significantly positive relationships with soil organic matter (SOM) and total nitrogen (TN) content. Large pores (>1,000 μm) showed a clear decrease, especially in open‐air fields, possibly due to the disappearance of the original straw residues in the surface layer. Small and medium pores in the plough layer increased in greenhouse fields, whereas the opposite occurred in open‐air fields. Overall, compared with open‐air systems, long‐term organic greenhouse patterns had a significantly positive effect on soil pore attributes.     

5R机器人运动分析

本文应用几何方法推出了5R机器人正、反问题的速度,加速度解算方程。成功地解决了运动学变量之间的耦合问题。     

Strategic Approaches for Implementing International Cooperation in Industrialised Housing in Chongqing

The paper deals with the concept of housing industrialisation, the importance of promoting industrialised housing in Chongqing. It analyses the current condition and the possible implementation approaches for developing industrialised housing in Chongqing. It addresses the aim, objectives, suggested organisation structure and the rules and responsibilities of each party in this project. The paper also mentions the importance for international cooperation and what overseas participants can offer for this project.