不同分子量壳寡糖对黑麦草种子萌发和幼苗抗病酶活性影响的研究

采用平均分子量分别为3000、5000、10000的0.3%(w/v)壳寡糖溶液处理黑麦草种子并对处理过的种子进行发芽试验和幼苗抗病酶活性的测定。结果表明:三种不同分子量壳寡糖溶液处理黑麦草种子,均可以提高黑麦草种子的发芽率、发芽指数和活力指数,并且提高了幼苗的叶绿素、可溶性蛋白的含量。增强了幼苗的过氧化物酶(POD)活性,诱导了病程相关蛋白(即,几丁质酶和β-1,3-葡聚糖酶及苯丙氨酸解氨酶)的表达。其中,以平均分子量为10000的壳寡糖对种子活力及幼苗的生长和抗病酶活性的影响最好,其发芽指数和活力指数分别比对照提高了32.64%、60.47%;苗高、可溶性蛋白含量、苯丙氨酸解氨酶、几丁质酶和β-1,3-葡聚糖酶活性分别比对照提高了20.98%、33.80%、43.17%、15.73%、26.41%。     

一种具有实用价值的螺旋线

介绍了一条新型螺旋线，该线有理论推导，可广泛应用于通风机，水泵壳体的型线设计上，有很高的实用价值。该螺旋线能够直接用仪器绘出，可以近似替代其它螺旋线。     

“369”牛羊高效增乳剂对奶山羊泌乳性能的影响

将泌乳期奶山羊３０只均分为试验组和对照组，试验组添加“３６９”牛羊高效增乳剂。结果表明，该增乳剂具有显著增乳效果，试验组日均产奶量高于对照组２１．６％（Ｐ＜０．０１）。两组间乳脂、乳糖和乳蛋白含量均无显著差异（Ｐ＞０．０５）．试验组ｃＡＭＰ和ｃＧＭＰ明显升高，增长率分别达４０．７％和４７．１％，与对照组相比差异极显著（Ｐ＜０．０１），且与产奶量正相关（ｒ＿（ｃＡ）＝０．９２１，ｒ＿（ｃＧ）＝０．９０３）．甲氧氯普胺在乳中残留量很低，平均１．６１μｇ·ｍＬ￣（－１）试验组隐性乳房炎阳性率显著低于对照组（Ｐ＜０．０１）。     

施肥方法对烤烟氮磷钾利用率及产量品质的影响

1991年在零陵、郴州烟区采用田间试验研究了肥料深施与浇施及基肥与追肥分配比例对烤烟氮、磷、钾利用率及产量品质的影响.结果表明,以氮、钾肥全作追肥浇施处理,肥料利用率,烟叶产量及产值最高,品质也较好;20%氮、钾作追肥深施,80%作追肥浇施处理次之;而将氮、钾肥及有机肥全部深施处理的效果较差.     

Ecological degradation in protected areas: the case of Wolong Nature Reserve for giant pandas

It is generally perceived that biodiversity is better protected from human activities after an area is designated as a protected area. However, we found that this common perception was not true in Wolong Nature Reserve (southwestern China), which was established in 1975 as a "flagship" protected area for the world-renowned endangered giant pandas. Analyses of remote sensing data from pre- and post-establishment periods indicate that the reserve has become more fragmented and less suitable for giant panda habitation. The rate of loss of high-quality habitat after the reserve's establishment was much higher than before the reserve was created, and the fragmentation of high-quality habitat became far more severe. After the creation of the reserve, rates of habitat loss and fragmentation inside the reserve unexpectedly increased to levels that were similar to or higher than those outside the reserve, in contrast to the situation before the reserve was created.     

Atomically resolved single-walled carbon nanotube intramolecular junctions

Intramolecular junctions in single-walled carbon nanotubes are potentially ideal structures for building robust, molecular-scale electronics but have only been studied theoretically at the atomic level. Scanning tunneling microscopy was used to determine the atomic structure and electronic properties of such junctions in single-walled nanotube samples. Metal-semiconductor junctions are found to exhibit an electronically sharp interface without localized junction states, whereas a more diffuse interface and low-energy states are found in metal-metal junctions. Tight-binding calculations for models based on observed atomic structures show good agreement with spectroscopy and provide insight into the topological defects forming intramolecular junctions. These studies have important implications for applications of present materials and provide a means for assessing efforts designed to tailor intramolecular junctions for nanoelectronics.     

GC-MS鉴定叶绿素皂化母液提取物

本文报道GC-MS鉴定莫合烟叶叶绿素皂化母液提取物。分离出75个组份,鉴定其中主要组份为叶绿醇,含量13.18％;十六碳醛,含量11.52％;6,10,14-三甲基-2-十五酮,含量6.24％;3-甲基戊酸乙酯,含量5.05％;1-甲基戊苯,含量2.96％;9,12,15-十八碳三烯酸乙酯,磷量2.03％,叶绿醇、十六碳醛,6,10,14-三甲基-2-十五酮和十八碳三烯酸乙酯均有利用价值。     

小麦品质与面条品质关系的研究

以普通机制面条为对象，研究了小麦品质指标对面条品质的影响。结果表明，蛋白质含量、面团稳定时间是影响面条蒸煮吸水率的主要品质指标，沉淀值是影响干物质失落率、蛋白质损失率的主要品质指标。干物质失落率是面条品质重要的评价指标。     

甘肃省非物质文化遗产旅游开发SWOT分析

随着中国有越来越多的非物质文化遗产进入联合国非物质文化遗产名录,非物质文化遗产的保护日益受到社会各界的关注,以旅游开发来促进非物质文化遗产的保护和传承成为旅游界的一项新课题。甘肃拥有丰厚的非物质文化遗产,文中在全面介绍甘肃省非物质文化遗产赋存状况的基础上,运用SWOT分析法,详细分析了甘肃非物质文化遗产旅游开发的优势、...     

滨海盐渍化土壤理化性质与小麦生产间的关系

为促进滨海区域粮食生产,以盐渍化麦田为研究对象,在测定土壤(0~20 cm)基本性质及小麦产量、生物量基础上,分析土壤肥力特征与小麦生产能力间的关系。结果表明,土壤含盐量与小麦产量、地上部生物量(生物量)呈极显著负相关(p0.01),其关系符合三次函数方程。若以4 500 kg hm-2作为最低目标产量,土壤含盐量应在3.1 g kg-1以下。土壤有机质含量与土壤含盐量呈显著负相关(p0.05),与小麦产量、生物量呈极显著正相关(p0.01)。土壤有机质含量增加能够降低盐渍化程度,促进小麦生产。将直接相连的下层(10~20 cm)与上(表)层(0~10 cm)土壤含盐量比值作为抑盐效率(E),来评价有机质的抑盐作用,表层土壤有机质含量与E符合二次函数方程,有机质含量超过19.1 g kg-1时,抑盐效果显著,可以作为土壤肥力培育目标值。此外,提高土壤速效钾含量对小麦生产也具有显著促进作用。研究结果对研究区域及相似地区进行土壤肥力培育和粮食生产具有重要意义。