渗透胁迫下小麦幼苗CaM含量变化及其与含水量的关系研究

试验研究结果表明,PEG-6000(-0.73MPa)渗透胁迫下小麦幼苗含水量降低,胁迫12h时叶片钙调素(CaM)迅速增加,之后低于对照,而根系在胁迫12h时钙调素含量降低,胁迫48h时达到高峰后迅速下降。渗透胁迫下氯丙嗪(100μmol/L)降低叶片相对含水量及干物质量,增大根系质膜透性,抑制根系和叶片的伸长。     

内充种垂直轮式新型小麦精量排种器的研究

文章揭示了该新型小麦精量排种器及其核心——排种元件的结构特点，分析论述了该排种器精播小麦的基本原理和参数。排种元件以容腔容积排种，没有带动层，排种定量、准确、可控。     

Phylogenetic analysis of complete 5′ external transcribed spacers of the 18S ribosomal RNA genes of diploid Aegilops and related species (Triticeae, Poaceae)

PCR systems were designed to amplify the entire 5 external transcribed spacer (ETS) region of the 18S rRNA gene of all the diploid species of Aegilops and several other taxa closely related to domesticated wheat. Phylogenetic analysis was performed on the complete ETS sequences using the neighbor-joining, maximum parsimony, and maximum likelihood methods. Among the individual taxa studied, speciation in Secale is very recent. In the case of the A genome diploids, the results support the theory that the A genomes of wheat have experienced reticulate evolution owing to introgression. The B and G genomes of tetraploid domesticated wheats form a clade with Ae. speltoides in which the B genome diverged first and the G genome more recently. It was demonstrated that the complete ETS sequences of the Triticeae yield coherent phylogenetic information. The ETS is a useful tool for studying the phylogeny of closely related species.     

麦类引种优选与抗逆性状初步分析

1991年从日本引进国外麦类品种10252个，在我国黄淮海平原盐渍地上种植。经1992--1994年系统观察、分析和鉴定，初步选择出适合该类型区种植的高产、优质品种及大、小麦亲本材料。     

中国种业机械化现状调研与发展分析

种业机械化是种业现代化的重要基础和前提,是涵盖品种选育、品种试验、制种生产、种子加工等多环节的系统工程。为了系统梳理中国种业机械化发展成果与存在问题,有效推进种业机械化发展、促进种业现代化建设,该文从田间试验机械化、制种生产机械化、种子加工机械化等方面阐述了国内种业机械化现状调研情况和国际种业机械化发展经验,分析了中国种业机械化存在的主要问题:种业装备企业普遍规模小、装备差、科研投入少,整体水平与国外存在较大差距,装备功能有待扩展、结构设计有待优化、现代化控制水平有待提高等;提出了种业机械化研究重点:1)主要农作物品种试验机械化关键装备研究;2)主要农作物制种生产机械化关键装备研究;3)主要农作物种子低损高效精细加工技术集成研究。指出了"规模化、标准化、集约化、机械化"种子生产是现代种业持续、健康发展的重要保障和基本发展方向。     

Effects of tillage on productivity of a winter wheat-vetch rotation under dryland Mediterranean conditions

An experiment was conducted to determine the effects of three tillage systems on crop yield in a winter wheat-vetch (Vicia sativa L.) rotation during 3-year growing seasons on a clay-loam soil in the northwest region of Turkey. The three tillage treatments were: (1) conventional tillage (CT); (2) shallow tillage (ST); (3) double disk tillage (DD).The wheat grain yield was significantly affected by tillage when averaged across years. The highest wheat grain yield was obtained with shallow tillage treatment. The year affected wheat grain yield significantly, mainly due to the distribution of rainfall through the growing season and probably due to the wheat-vetch rotation. Heads density and head length increased significantly with shallow tillage when compared with conventional tillage. Tillage practices had no significant influence on thousand kernel weight. Results from this study indicated that for a dryland wheat-vetch rotation cropping system, shallow tillage had higher wheat grain yields than that obtained from conventional tillage. Furthermore, mouldboard ploughing tillage in this crop rotation could be replaced by shallow tillage that would increase yield and would be likely to improve soil properties in the long-term. On the other hand, double disk tillage proved to be a promising soil management practice to improve vetch grain yield when compared with conventional tillage.     

Increased degradation of phenanthrene in soil by Pseudomonas sp. GF3 in the presence of wheat

A phenanthrene-degrading bacterial strain Pseudomonas sp. GF3 was examined for plant-growth promoting effects and phenanthrene removal in soil artificially contaminated with low and high levels of phenanthrene (0, 100 and 200 mg kg⁻¹) in pot experiments. Low and high phenanthrene treatments significantly decreased the growth of wheat. Inoculation with bacterial strain Pseudomonas sp. GF3 was found to increase root and shoot growth of wheat. Strain GF3 was able to degrade phenanthrene effectively in the unplanted and planted soils. Over a period of 80 days the concentration of phenanthrene in soil in which wheat was grown was significantly lower than in unplanted soil (p<0.05). At the end of the 80-d experiments, 62.2% and 42.3% of phenanthrene had disappeared from planted soils without Pseudomonas sp. GF3 when the phenanthrene was added at 100 and 200 mg kg⁻¹ soil, respectively, but 84.8% and 70.2% of phenanthrene had disappeared from planted soils with the bacterial inoculation. The presence of vegetation significantly enhances the dissipation of phenanthrene in the soil. There was no significant difference in soil polyphenol oxidase activities among the applications of 0, 100 and 200 mg kg⁻¹ of phenanthrene. However, the enzyme activities in planted and unplanted soils inoculated with the strain Pseudomonas sp. GF3 were significantly higher than those of non-inoculation controls. The bacterial isolate was also able to colonize and develop in the rhizosphere soil of wheat after inoculation.     

山西省草地资源人口承载量研究

为了在黄河中、上游地区加快实施中央“退耕还林还草恢复生态环境”的决策,正确估算区域人口的承载量是一项基础性的研究工作。以山西省和山西省黄河流域为研究区域,利用相关统计、试验数据,设计不同草地利用率层次和不同肉食消费水平等次,对山西省和山西省黄河流域及其各县市草地资源人口承载量进行了单项和组合型的动态变化研究,为山西省区域退耕还林还草和生态移民工作提供了理论基础。     

Influence of selenium on oxidoreductive enzymes activity in soil and in plants

The aim of this greenhouse experiment was the assessment of the influence of H₂SeO₃ at soil concentrations of 0.05, 0.15 and 0.45 mmol kg⁻¹, on the activity of selected oxidoreductive enzymes in wheat (Triticum aestivum). The wheat plants were grown in 2 dm³ pots filled with dust-silt black soil of pH 7.7. Applied H₂SeO₃ caused activation of plant nitrate reductase at all concentrations, but activation of plant polyphenol oxidase at only two lower concentrations. The highest concentration caused inhibition of polyphenol oxidase and peroxidase. Plant catalase activity decreased under the influence of 0.15 and 0.45 mmol kg⁻¹ concentration. After the final analysis Se was quantified in plants and soil. The amounts in plants were: control (unamended soil) 1.95 mg kg⁻¹; I dose (0.05 mmol kg⁻¹) 18.27 mg kg⁻¹; II dose (0.15 mmol kg⁻¹) 33.20 mg kg⁻¹ and III dose (0.45 mmol kg⁻¹) 38.37 mg kg⁻¹, in soil: 0.265 mg kg⁻¹; 3.61 mg kg⁻¹; 10.53 mg kg⁻¹; 30.53 mg kg⁻¹; respectively. Simultaneously, a laboratory experiment was performed, where the activity of soil catalase and peroxidase were tested after 1, 3, 7, 14, 28, 56, and 112 days after Se treatment. Peroxidase activity in soil decreased with increasing Se content, over the whole experiment. The lowest dose of Se caused activation a significant 10% increase in catalase activity, but the influence of others doses was unclear.     

Long-term continuous cropping in the Pacific Northwest: Tillage and fertilizer effects on winter wheat, spring wheat, and spring barley production

Conventional tillage winter wheat (Triticum aestivum) (WW)–summer fallow reduces soil productivity and increases soil erosion. Conservation tillage management, together with intensive cropping may have the potential to reverse these sustainability concerns. The objective of this study was to determine the effects of conventional tillage (CT) and no-tillage (NT) systems on grain yield of long-term annual cropping of monoculture WW, spring wheat (SW), and spring barley (Hordeum vulgare) (SB) grown with or without fertilizer, in the Pacific Northwest region of the USA. In unfertilized crops, grain yield of WW, SW, and SB was 15%, 25%, and 50% higher, respectively, in CT than in NT plots, an indication of the involvement of yield limiting factors under the NT cropping system. When fertilized, there were no significant differences in grain yield of WW. Yields of SW and SB, however, remained 21% and 15% higher, respectively, in CT than in NT, an indication that factors other than fertility were involved. These results suggest that in order for NT management to be widely adopted by area growers, the yield-limiting factors need to be addressed.