不同品种梨果实石细胞含量的比较研究

本试验以砀山酥梨、黄金梨、水晶梨、香梨4个品种梨果实为试材,研究了不同品种不同部位的石细胞含量,结果表明:同一个品种外、中、内三个部位石细胞含量存在着极显著的差异,石细胞含量的排序为:水晶梨内部的石细胞含量最大,显著的高于中部和外部;黄金梨内部的石细胞含量显著的大于中部和外部的石细胞含量;砀山酥梨内部的石细胞含量最大,中部的最少;香梨内部的石细胞含量显著的高于外部和中部的石细胞含量;不同品种同一部位的石细胞含量均存在着极显著的差异.砀山酥梨的外、中、内三个部位的石细胞含量均显著的大于水晶梨、黄金梨和香梨外、中、内三个部位的石细胞含量.不同品种间细胞含量存在着极显著差异,砀山酥梨的石细胞含量最多,极显著的高于另外三种梨的石细胞含量.     

用压力容积图进行管道试压方式研究

目前国内外采用的管道试压方式大致有两种，一种是在试压时控制管道环向应力水平；另一种是以管道中试压介质的压力容积图控制试压，以前者作为试压方式虽然简便，但因其将每根管子管材的屈服极限作为非变量，因而用同一应力水平试压极有可能造成管材过分屈服或试压不足，试压应力难以确定。而后者只控制试压过程中压力容积图的线性关系，即在图形出现非线性时停止加压，避免了试压应力骓以确定的问题，多项研究和统计表明，试压应力     

Integrated assessment of diversification of rice-wheat cropping system in Indo-Gangetic plain

Diversification of rice-wheat cropping system may improve the productivity and sustainability of agricultural production in the Indo-Gangetic plane region (IGPR), but the choice of alternative sequences to be used requires integrated assessment of various crop sequences. A long-term field experiment was initiated during 2000–01 on sandy loam soil at Banaras Hindu University, Varanasi, India to assess 10 rice-based cropping sequences – rice-wheat, rice-chickpea, rice-wheat-green gram, rice-wheat-Sesbania (green manure), rice-mustard-green gram, rice-lentil-cowpea (fodder), rice-pea, rice-lentil + mustard (3:1)-cowpea (fodder), rice-maize (cob) + vegetable pea (1:1)-cowpea (fodder) and rice-potato-green gram in randomized block design with four replications. The data contained in this paper are for the year 2002–03 and 2003–04. Substitution of rice-wheat with 300% intensity cropping sequences particularly with rice-potato-green gram resulted in maximum production cost but gave the highest system productivity, net return, benefit:cost ratio, production efficiency, profitability and energy productivity. Inclusion of summer grain/fodder legume or Sesbania for green manuring improved the content of soil organic matter. The soil P status was positively affected in all the sequences and particularly those with summer crops. Decline in soil available K in all the sequences indicated inadequacy of present recommended rate of fertilizer K to all the component crops in different sequences.     

普拉提对女大学生健身功效的实验研究

探讨普拉提练习对女大学生的健身功效及机制,研究样本为在校大二女学生40名(年龄为21. 12士1. 08),其中对照组(v=20)进行太极养生课程练习,而实验组(a=20)则进行为期14周的普拉提垫上课程教学,通过对试验对象的身体素质及身体形态等指标试验前后比较分析。主要结论:1)普拉提对女大学生的形态具有良好的减脂塑型效果,尤其是腰腹部,其次是臀部和大腿。2)普拉提对女大学生的各项身体素质产生不同影响,其中腹背部肌肉力量和耐力以及身体柔韧度提高非常明显,同时灵敏性和协调能力也有发展。     

Screening potatoes for resistance to late blight (Phytophthora infestans) under field conditions

Summary Late blight incidence under natural epiphytotic conditions was recorded on 270 potato germplasm accessions for three years. Replication effect was non-significant, whereas genotype and year effects were significant for AUDPC (area under disease progress curve). Disease incidence on the second date of observation (when the control had almost completely blighted) accounted for 85 to 96 percent of the variation in AUDPC. Spearman’s Rank correlation coefficients between AUDPC and disease incidence grades scored on 1–9 and 1–5 scales (on second date of observation) based on the means of three years data were similar to those calculated based on the means of any two years. It is concluded that grading the accessions based on discrete scales at an appropriate single date for two years in a non-replicated trial would be sufficient robust to broadly group accessions into different levels of resistance to late blight. Ten accessions were found to be highly resistant.     

麻类作物分子标记技术应用进展

本文综述了分子标记在麻类作物物种演化及亲缘关系、遗传多样性、标记辅助选择和遗传图谱的构建上的应用，并展望了分子标记在麻类作物上的研究。     

苎麻分子育种与饲料用苎麻研究进展

苎麻遗传育种是提高其产量和品质的重要手段之一，由于育种技术的进步和苎麻新用途的开发．近年来苎麻育种领域发生新的变化。本文对中国农业科学院麻类研究所近年来在苎麻分子育种和饲料用苎麻研究两方面所做的主要研究工作和重要进展进行了概述和总结。     

技术进步对我国茶叶生产贡献率的估算

技术进步对20世纪80年代我国茶园生产增长的贡献率，在很大程度上能反映近30年技术创新对我国茶叶生产的影响。柯布－道格拉斯生产函数和索罗余值法的分析结果表明，1980年－1991年单产增加由时间变量解释部分为84．2％，它和集体茶场经营制度改革、技术创新以及幼龄茶园逐渐进入成年采摘期等因素有关，而1985年－1991年期间56．1％部分则主要是技术进步所致。     

Reduced fungicide inputs to controlPhytophthora infestans in potato cultivars with high levels of polygenic resistance

Summary Final disease ratings, apparent infection rates and areas under disease progress curves were used to calculate lower fungicide rates for potato cultivars with high levels of polygenic resistance toPhytophthora infestans. Areas under disease progress curves offered more reliable indications than final disease ratings or apparent infection rates. Control of epidemic development was achieved using 20–80% of the recommended application rates of mancozeb on plots of cvs Brodick. Cara and Torridon compared with full application rates on cv. Maris Piper.     

油茶对胁迫因子的响应机制研究进展

油茶为中国特有油料植物,是世界四大木本油料植物之一。国内外学者在油茶对胁迫因子响应机制上开展了大量研究,文章总结了近年来油茶胁迫因子的研究成果。研究发现,胁迫因子对油茶的形态结构、生理生化产生一定的影响,但油茶自身也可对胁迫因子产生协同响应以缓解不利影响,且不同油茶品种间的抗性存在一定的差异。在现有研究的基础上,建议未来油茶胁迫因子的研究可着眼于：油茶不同发育阶段的差异、不同地区油茶品种间的抗性差异、多因子协同耦合机制及模拟不同因子间的变动趋势、油茶胁迫因子调控基因机制等。