两系小麦不育系BNS雄性育性的转换

于2006-2009年在湖南长沙采用分期播种方法以两系小麦不育系BNS和对照百农矮抗58、农大211、农大3688和杨麦13为试验材料,研究了BNS雄性育性在南方生态区域的转换规律。结果表明:随播种期的推迟,BNS雄性育性表现为完全败育→高度不育→部分可育→完全可育的育性转换规律;雄性完全败育阶段以花粉典型败育为主;3月中、下旬开花阶段,花粉完全败育;4月上旬开花阶段,雄性育性发生转变,4月中旬开花阶段,花粉可育。雄性育性的转换伴随着开花习性发生转换。     

旺长期烤烟叶片的叶绿素荧光特性与激发能分配

以烤烟品种龙江911为试验材料,研究了烤烟植株上、中、下3个部位叶片实际光化学效率(ΦPSⅡ)和PSⅡ最大光能转化效率(Fv/Fm)的日变化,以及激发能的分配特性。结果表明,烤烟叶片Fv/Fm和实际光化学效率(ΦPSⅡ)中午降低,PSⅡ功能下调,有明显的光抑制。在光合有效辐射(PPFD)逐渐增强过程中,Fv/Fm和ΦPSⅡ降低,非光化学猝灭(NPQ)增加,激发能由PSⅠ向PSⅡ分配的比例增加,说明引起烤烟光抑制的原因除了NPQ之外,分配给PSⅡ能量增加是光抑制非常重要的因素。PPFD逐渐减小时,光抑制逐渐减缓,光化学效率恢复,激发能分配不平衡性系数(β/α-1)下降,PSⅡ能量负荷减轻,失活的PSⅡ恢复活性。     

利用抑制消减杂交法筛选低夜温诱导的蝴蝶兰生殖发育相关基因

花芽的发育是花品质形成与调控的生物学基础,温度是影响蝴蝶兰(Phalaenopsis hybrida)花芽分化与发育乃至花朵开放的重要因素。为鉴定低夜温诱导蝴蝶兰花梗芽分化和发育相关基因,以蝴蝶兰兄弟女孩品种为材料,利用抑制削减杂交技术,构建低夜温诱导的花梗芽与营养生长期顶叶的正向差减文库。PCR验证后,挑取300个阳性单克隆进行测序和分析,共获得207条非冗余序列(Gen Bank登录号:JK720764~JK720970)。这些基因覆盖了宽广功能范围的开花相关基因,提供了从营养生长期向生殖生长期转变相关分子机理方面的有益信息。Real-timePCR检测了具不同功能的23个基因在营养生长期顶叶和不同大小花梗芽中的表达水平。这些基因的表达量变化趋势不同,但在一定大小花梗芽中的表达量较营养生长期顶叶均有上调。与在营养生长期顶叶中的表达量相比,flowering locusT(FT)、APETALA1(AP1)、茉莉酮酸酯-O-甲基转移酶(JMT)基因和NADH泛醌氧化还原酶基因在各阶段花梗芽中的表达量均显著上调,表明这4个基因可能在低夜温诱导蝴蝶兰花梗芽分化和发育中起重要作用。本研究为深入探究低夜温诱导蝴蝶兰开花的分子机理提供了重要的基础资料。     

Properties and classification of selected volcanic ash soils from Abashiri,Northern Japan—transition of Andisols to Mollisols

Abstract

Properties and classification of four selected volcanic ash soils from Abashiri, Hokkaido were studied and the transition of Andisols to Mollisols was discussed. Two of the four pedons (Brown Andosol and Cumulic Andosol)¹ showed morphological, clay mineralogical, physical, and chemical properties common to most Andisols in Japan. However, the properties of the other two pedons (Acid Brown Forest soil and Brown Forest soil)¹ were considerably different from those of common Andisols in Japan. It was found that the changes in the andic soil properties or transition of Andisols to Mollisols was closely related to the progression of clay weathering, mainly the transformation of noncrystalline clay materials to halloysite. One of the four pedons (Brown Forest soil)¹had the clay fraction dominated by halloysite from the uppermost horizon down to the bottom of the profile and satisfied both andic and mollic requirements. Thus we concluded that the pedon is a transitional soil between Andisols and Mollisols and that the transition is closely related to the duration of surface weathering under relatively weak leaching conditions. The four pedons were classified according to the Andisol Proposal (Leamy et al. 1988, New Zealand Soil Bureau) as follows:

Pedon 1: Medial, amorphic (allophane/imogolite), frigid Typic Hapludand (Brown Andosol).¹ Pedon 2: Medial, amorphic (allophane/imogolite), frigid Typic Melanudand (Cumulic Andosol).¹ Pedon 3: Medial, amorphic (allophane/ imogolite), over kandic, frigid Typic Melanudand (Acid Brown Forest soil).¹ Pedon 4: Medial, kandic, frigid Typic Hapludand (Brown Forest soil).¹     

单薄壁墩连续刚构O号块实体分析

本文通过对广西阳鹿高速上一座70＋2×125＋70m单薄壁墩连续刚构为工程实例,采用MIDAS/FEA软件,对箱梁0号块建立空间实体模型,进行实体分析,分析0号块的受力特点,为优化设计作为参考。     

Do Provincial Forest Cover Changes Follow The Same Path in China? Evidence From 29 Provincial Regions During 1978–2013

China has undergone forest transition at the national level during the past decades. Previous studies, which have used econometric models with restrictive assumptions of slope homogeneity across provinces, might present statistically biased results on provincial forest cover change. This paper aims to examine whether provincial forest cover changes follow the same path in China by using an up-to-date panel data on forest cover rates for 29 provincial regions from 1978 to 2013 and an econometric model allowing for slope heterogeneity across provinces. Empirical results suggest that forest cover changed along U-shaped curves in most provinces, but there is no “one size fit all” curve for these provinces, whose forest cover rates at the forest transition point ranged from less than 1% to more than 40% and per capita GDPs varied from 2,114 CNY to 28,403 CNY (in 2013 CNY). In future study, both similarities and differences in forest cover change across provinces should be taken into account, main provincial contributors of national forest cover change needs to be identified, and an extended model that incorporates more explanatory variables affecting deforestation, reforestation or afforestation should be adopted to comprehensively investigate the mechanism underlying forest cover change in China.     

Cold Storage of Strawberry Plants

Abstract

Cold storage has not only been a good method to overwinter strawberry plants safely and to compensate for the lack of natural chilling. Initially cold stored plants were used for early spring cropping only. Meanwhile this technique has become a normal commercial practice among growers in central Europe and has given them the opportunity to extend the strawberry production season from July until January. Cold stored waiting bed plants have been used since the early seventies in The Netherlands and Belgium and currently represent an important part of strawberry production. These sixty-day-plants are planted mainly outdoors in the soil for a production from July until September. More recently waiting bed plants have gained popularity in the UK, Germany and northern Italy to extend the season. Alternatively in France and Germany cold stored runner (A+) plants are traditionally being used for a summer production outdoors followed by a spring crop. During the last decade module or tray plants have gained popularity for autumn cropping on substrate culture in plastic tunnels and greenhouses. During the most recent years the programmed “out of season” production of strawberries has become more important in several European countries. Intensive research has been going on concerning the improvement of the growing techniques and quality of plant material and cold Storage conditions.     

城乡经济转型中农地城市流转及决策研究述评

基于国内外相关文献回顾,分析了农地城市流转决策及支持系统的研究进展。研究发现,国内外学者的研究热点略有不同,研究水平和已取得的研究成果也存在较大差距;决策系统在我国农地城市流转中还处于研究较少的阶段;同时,针对我国的国情,国外的相关理论模型也存在一定的缺陷。     

松嫩平原星星草果后营养期无性系结构及其生长分析

针对松嫩平原自然条件下星星草(Puccinellia tenuiflora)单优群落独立株丛,采用随机挖掘整个分蘖丛的取样方法,对星星草果后营养期无性系结构及其生长规律进行了定量分析。结果表明,星星草无性系总构件数量为(49.07±29.74)个,分蘖株和分蘖苗分别占53.3%和46.7%;总生物量为(2.54±1.57)g,分蘖株和分蘖苗分别占90.7%和9.3%。随丛径的增加,分蘖株数量、分蘖苗数量、分蘖株生物量分别呈直线增加,总构件数量和总生物量呈幂函数增加,分蘖苗生物量呈对数函数增加;分蘖株生物量、总生物量分别与分蘖株数量和总构件数量呈直线函数关系,分蘖苗生物量与分蘖苗数量呈幂函数关系;其相关性均达到了极显著水平(P<0.01)。