Morphological variation within a sour cherry collection

Summary Morphological traits of 28 full-sib sour cherry (Prunus cerasus L.) families developed with pollen from European sour cherry selections were evaluated with principal component (PC) analysis. The traits which loaded on the first PC were size characters such as lateral length, leaf area, fruit weight, and trunk diameter increase. These character loading on the first PC could be interpreted as representing gradations between morphologies characteristic of the 2 presumed progenitor species, sweet cherry (P. avium L.) and ground cherry (P. fruticosa Pall.). Mean family differences in trunk diameter increase, lateral length, leaf area, and fruit weight varied approximately 12, 3.7, 2.5, and 2 fold, respectively. These results suggest that it may be possible to select sour cherry hybrids approaching the tree and fruit size of either progenitor species. The results are discussed in reference to germplasm collection and the potential of certain cultivars and hybrids as parents.     

The origin of six-rowed ‘wild’ barley from the western Himalaya

Summary Plants were grown from seed of two-rowed wild barley, Hordeum spontaneum, and six-rowed brittlerachised barley. H. agriocrithon, collected in Ladakh, north-western India. Whereas the H. spontaneum remained true to type, segregation for morphological characters was observed in progeny rows grown from heads of H. agriocrithon plants. The H. agriocrithon heads also showed segregation for a biochemical character, the polypeptide pattern of the endosperm storage protein fraction (hordein). The H. agriocrithon seed therefore originated from natural hybridization between cultivated H. vulgare and weedy H. spontaneum. Crosses of H. vulgare and H. spontaneum gave progeny which resembled H. agriocrithon and showed similar hordein polypeptide segregation patterns. The results indicate that six-rowed brittle-rach ised barleys from the Himalayas have a similar origin to forms found in the Middle East, and that H. agriocrithon does not play a direct role in the evolution of barley.     

多效唑对天津水蜜桃生长发育影响的研究

对长势旺产量较低的天津水蜜桃进行了叶面喷洒多效唑(PP_(333))营养生长抑制剂的研究.结果表明,新梢生长受抑的程度与多效唑的浓度呈正相关.叶绿素的含量与一定浓度的多效唑处理具有密切的关系.较高浓度和高浓度的乡效唑处理可提高果实中维生素C的含量、单果重以及果品质量,而对果实中可溶性固形物、果实硬度、着色指数和单叶面积无影响.     

糜子的小孢子发生与花粉发育

观察结果表明,糜子小孢子发生与花粉发育的细胞学过程,与稻麦等禾本科作物相似:减数分裂属顺序型,一般形成等面形四分体;也观察到线形、T形及各种倾斜形的四分体;小孢子经两次有丝分裂发育成三核型花粉粒;成熟的花粉粒为球形,具一个萌发孔,直径48(45～52)μm.花粉发育过程中,生殖细胞的运动、淀粉积累时期及花粉粒体积增大动态的观察结果与一些报道不同.糜子的小孢子发生和花粉发育与花药长度存在密切关系,而花药长度随时间呈S形增长方式.本文利用上述关系求得小孢子发生与花粉发育各阶段的经历时间.     

国外低影响开发雨水资源利用对中国海绵城市建设的启示

[目的]研究美国、英国、德国、日本、新加坡和澳大利亚的低影响开发雨水资源利用情况,为中国海绵城市建设在管理、技术等方面提供一定依据。[方法]通过调查研究,从政策法规、应用技术、管理体系、公众意识等方面系统地梳理国外低影响开发雨水资源利用经验,并结合国内实际,探讨促进中国海绵城市建设发展的建议。[结果]针对目前中国海绵城市建设遇到的城市内涝、缺水及生态环境问题,可从制定和完善相关政策法规,加强先进技术的研发和应用,创新融资渠道、优化管理体系,提升公众意识等方面进行改进。[结论]合理借鉴国外已经成熟的低影响开发雨水资源利用经验,能够更好地推进中国海绵城市建设。     

Prospective use of collected fog water in the restoration of degraded burned areas under dry Mediterranean conditions

A mountainous plot located in the interior of the Valencia region (east coast of the Iberian Peninsula) was identified for reforestation using the fog-water collection potential prevailing in the area. Fog data were obtained by means of an instrument ensemble consisting of a passive cylindrical fog-water collector, a rain gauge, a wind direction and velocity sensor and a temperature and humidity probe. Preliminary results gave rise to the additional deployment of a low-cost 18-m² flat-panel collector connected to three 1000-l tanks for larger scale fog-water collection and storage. The 2007 annual rate of fog water that could be derived from the instrument ensemble amounted to 3.3 l/m²/day, which turn out to fill up the storage tanks completely in only 5 months, even though the flat-panel collector could not be operative 100% of the time. The study made use of the in situ stored water and a micro-irrigation network to irrigate a plot of reforestation seedlings through small water pulses localized deep in the planting hole during the summer dry period. Until the present, this forest location had always shown a difficult self-recovery due to the high level of land degradation resulting from recurrent forest fires in the past. Results indicate that survival rates and seedling performance of the two species planted, Pinus pinaster and Quercus ilex, improved with the use of small timely waterings and additional treatments with composted biosolid.     

Differential reaction of wheat cultivars to hot environments

Summary Ten to 20 spring wheat (Triticum aestivum L.) cultivars of Israeli origin were grown in three winter (normal) and two summer (abnormal) growing seasons. During the period of emergence to anthesis mean daily temperature was on the average 12°C higher and photoperiod was about 3 h longer in the summer than in the winter. Data was collected on the durations of the periods from emergence to double-ridge (GS1), double ridge to anthesis (GS2) and anthesis to grain maturation (GS3), as well as on yield and yield components.The duration of all developmental stages was reduced by high temperature. While the duration of GS2 was the most thermo-sensitive, it may also have been reduced by the longer summer photoperiod. The effect of photoperiod on GS2 could not be isolated, but the results were interpreted to show that the effect of photoperiod on the duration of GS2 was relatively small.The most heat-affected yield component was number of grains per spikelet and the least affected component was the number of spikes per plant. High temperature reduced grain weight via reduced grain growth duration and not grain growth rate. A general linear regression model of yield on its components revealed that while variation for number of spikes per plant had the greatest effect on yield variation among cultivars in the winter, variation for number of grains per spikelet and spikelets per spike were by far the most important in the summer. Grain weight was the least important component, in this respect, in all seasons. Varieties which sustained the highest yield in hot environments were able to maintain the longest duration of GS2 and the highest number of grain per spike.     

基于SWOT分析的灌区专管机构发展策略研究

从灌区专管机构的角度探讨灌区管理体制改革的相关问题,提出采用SWOT分析法研究灌区专管机构改革与发展策略的制定方法。以五岸灌区专管机构为例,分析了灌区的外部环境和内部条件,并对内部条件的优势、劣势以及外部环境的机会、威胁进行分析,建立了SWOT矩阵,以此研究提出了灌区相应的发展策略。     

我国棉花生产机械化技术现状与发展趋势

棉花是我国重要的经济作物和纺织工业原料,在国民经济中占据着重要的地位.在棉花生产发展的历程中,棉花生产技术与装备的进步对棉花生产起到重大作用.当前,我国棉花的生产正经历从依靠人力手工作业为主进入实用机械作业的综合集成技术的关键时期,继而发展到模式化与标准化生产技术体系.为此,我系统地介绍了我国棉花机械化生产技术应用现状与存在的问题,针对问题提出了解决的措施,讨论了其发展趋势,从而为我国棉花产业的健康与持续发展提供技术支撑和依据.     

鼠、兔核质杂交及早期胚胎发育的研究

以2~8细胞期鼠胚细胞为供体核,选用注射hCG后15h、17h的兔卵母细胞为受体胞质,施加1.6 kv/cm、160、两次脉冲的电场条件,间隔20min,融合液为含Ca、Mg的0.3mol/L甘露醇,适于鼠、兔种间EOBC的融合激活。小鼠2—细胞、4—细胞期胚细胞与兔去核卵母细胞融合率高于8—细胞期胚细胞,分别为83%、80%及62.5%,桑囊胚发育率差异不显著。体细胞共同培养系统和Taurine能显著提高鼠、兔核质杂交胚的体外发育能力。