Cold acclimation of winter and spring peas: carbon partitioning as affected by light intensity

Like most plants, pea (Pisum sativum L.) becomes tolerant to frost if it is first exposed to low non-freezing temperatures, a process known as cold acclimation. Cold acclimation is a complex process involving many physiological and metabolic changes. Two spring dry peas, two winter dry peas and one winter forage line were exposed to cold temperature in a controlled environment in two experiments, one using low light intensity and the other regular light intensity. Plants were harvested throughout the experiment and dry matter accumulation, water content, soluble and insoluble sugar concentrations were determined from shoot and root samples. Cold acclimation did not occur when temperatures were low if light intensity was low, even in winter peas. In contrast, with regular light intensity, the winter peas acquired more freezing tolerance than spring peas and a close relationship was found between the soluble sugar concentration of leaves just before the frost and the degree of freezing tolerance obtained by the different genotypes. Relationships between freezing tolerance and carbon partitioning between shoot and roots are discussed.     

愈合期不同光照强度对黄瓜嫁接苗的影响

研究愈合期不同光照强度对黄瓜嫁接苗定植前质量的影响,旨在为黄瓜嫁接愈合光照的精确化调控提供参考依据。试验将嫁接愈合分为1~3 d、4~6 d、7~10 d 3个时段,分别给予6种不同光照强度梯度处理。结果表明,愈合期在45-90-135μmol·m^-2·s^-1的光照强度梯度下嫁接苗地上部与地下部形态生长显著提升,形态综合指标最佳,较传统愈合条件(0-30-45μmol·m^-2·s^-1)下可溶性糖与可溶性蛋白含量分别提升了65.87%、15.85%,叶绿素荧光参数也表现最优。综合分析表明,45-90-135μmol·m^-2·s^-1的光照强度梯度最有利于黄瓜嫁接苗生长,最有利于嫁接苗可溶性糖和可溶性蛋白的积累,且叶片的光合电子传递效率、光合效率和自我保护调节机制较好,可作为黄瓜嫁接愈合期的光照强度条件,这为提升黄瓜嫁接苗的商品质量提供了一些理论依据。     

Discussion of the Application and Foreground of Falling Water Aeration with the Process of Sewage Treatment

The engineering design of sewage treatment plant for the Chongqing city, P. R. China is analyzed in this paper. Considering the situation of China and other projects, the characteristics of falling water reactor for the environment protection project and economy of investment is introduced ; the application and foreground of falling water aeration in the process of sewage treatment is discussed, such as Oxidation - ditch, SBR, and so on. The conclusion indicated that the falling water aeration can be designed and used as an independent aeration, and, it is an upgraded technology of sewage treatment which is adaptive for city water environment control in middle and small towns in China. The falling water aeration may reduce running cost of the sewage treatment plant, is adaptive for foothill and the mountainous areas, and reduces project investment and environments damage.     

The Shortcoming and Improvement of the Project Break-Even Analysis Method

This paper points out the shortcoming of the existing project break-even analysis method. A new improved method-the dynamic project break-even analysis method has been put forward.     

Knowledge Representation for Rotative Machine Fault Diagnosis Based on Semantic Net

Aiming at knowledge representation problem of expert system for rotary machinery fault diagnosis, semantic net knowledge representation is discussed. Semantic net to represent expert knowledge of rotary machinery fault diagnosis is explored. Its realizing method is afforded in computer language, in addition, demostrating model is also developed in Visual C++. The result shows good validity of the knowledge representation.     

Genetic Variability for Grain Yield and Protein Content in Barley and Its Modification by Net Blotch

Protein content, yield and 1000-grain weight of healthy and net blotch-diseased plants were studied in a diallel cross programme concerning nine different varieties of barley (Hordeum vulgare L.). F₁ hybrids and their parents were grown in the field in two randomized block design experiments each with three replications (three inoculated and three non-inoculated plots). General and specific combining abilities were determined for yield, protein percentage, 1000 grain weight, protein yield, and non-protein yield. A high genetic variability for the traits studied was observed. Non-protein yield and 1000-grain weight decreased significantly in inoculated plants where protein yield was not affected. Significant general and specific combining abilities were observed for all traits. Values for general and specific combining abilities were, in some cases, significantly modified by net blotch of barley. This indicates that attention must be paid to the danger of drawing conclusions in quantitative genetics studies dealing with both diseased and healthy plants.     

Diversity among Finnish net blotch isolates and resistance in barley

Summary Seedlings of a differential barley (Hordeum vulgare L.) series (21 genotypes) and of six check genotypes were used in the greenhouse to assess variation in virulence among 20 single-spore isolates of the net blotch pathogen. Pyrenophora teres Drechs. f.teres Smedeg., collected from various sites in Finland. The experiment was run twice and symptom expression was recorded on the first three leaves. Analysis of second leaf symptom scores from Run 1 indicated differences in virulence between isolates, all of which were pathogenic, and differential resistance among the barleys. The virulence of P. teres isolates appeared to be conditioned by the host barley from which the isolate derived; the average virulence of isolates collected from a susceptible host was greater than that of isolates collected from a less susceptible host. Results from Run 2 were similar regarding resistance within the barleys, but variation in virulence among the P. teres isolates was not consistent with that from Run 1. CI 9819 caries duplicate genes for resistance to P. teres (Rpt1b and Rpt1c), and CI 7548 possesses Rpt3d. Both genotypes were highly resistant to all isolates. The Rpt1a gene of Tifang (CI4407) conferred resistance to all isolates in Run 2, but only to about half of the isolates in Run 1. The checks, including two of the symptomatically most resistant Nordic barley genotypes, were universally susceptible during these stringent tests. No selective pressure has been placed on Finnish isolates of P. teres through previous deployment of major resistance genes, and it is speculated that any variation in virulence among isolates is likely to be due to a combination of evolutionary forces including, natural selection, random genetic drift and gene flow.     

不同培养基质及条件对三种报春花种子萌发及幼苗生长的影响

在不同培养基质及条件下对海仙花报春(Primula poissonii Franch.)、香海仙报春(Primula wilsonii Dunn)、多脉报春(Primula polyneura Franch)的种子萌发及幼苗生长进行了研究.结果表明,上述3种报春花的种子萌发情况是多脉报春＞香海仙＞海仙花报春.在四种不同的培养基中,MS及N6培养基对报春花种子萌发及幼苗生长比改良WPM、Miller培养基好.不同糖浓度及pH4.5～6.5对报春花种子萌发及幼苗生长无明显影响.GA处理能缩短报春花种子萌发时间.人工气候箱条件下报春花种子萌发及幼苗生长比在培养室的条件下更好.光照对种子萌发有促进作用,但当光照强度增强时,又会使报春花的幼苗叶片白化,产生光抑制,造成幼苗的死亡.在遭受光胁迫时,海仙花报春比多脉报春有较强的适应性.     

Virulence studies of Swedish net blotch isolates (Drechslera teres) and identification of resistant barley lines

Six Swedish and one Canadian single spore isolate of Drechslera teres f. teres were used to screen 109 barley lines for disease resistance and to select a differential set of barley lines for use in assessing pathogen virulence. A large variation for net blotch resistance was found among the 109 barley lines which were classified into four groups, those showing: 1) only resistant reactions; 2) differential reactions; 3) only intermediate reactions and 4) only susceptible reactions. The European commercial varieties included, showed susceptibility to all Swedish isolates, but a few were resistant to the Canadian isolate. The 18- member differential set separated 25 Swedish and two Canadian isolates of D. teres into 14 pathotypes, three of which made up 59% of the isolates. Only one barley differential (CI 9776) was resistant to all net form isolates. Host selection on the pathogen seems to be present as all six isolates obtained from cv. Golf belonged to the same pathotype and 4 of 5 isolates from cv. Karin shared the same virulence pattern. The net form of net blotch (D. teres f. teres) predominated in the sampled regions and only one of 26 Swedish isolates was of the spot form (D. teres f. maculata). This revised version was published online in July 2006 with corrections to the Cover Date.     

Effect of two wheat genotypes and Swedish environment on falling number, amylase activities, and protein concentration and composition

Variation in falling number, amylase activities, protein concentration and composition were investigated in two wheat cultivars grown in Sweden over two seasons, in four locations, with four N fertilizer rates, with and without fungicide treatment. The results showed that;