Habitat-induced reciprocal transformation in the root phenotype of Oriental ginseng is associated with alteration in DNA methylation

Oriental ginseng is an important medicinal plant that grows in 2 major forms or ecotypes, wild and domesticated. Each form differs conspicuously in root phenotype, but can be converted from one type to another by habitat. Here we show that the habitat-induced transformation of ginseng root phenotype was accompanied by alteration in cytosine methylation at a large number of 5′-CCGG-3′ sites detected by the methylation-sensitive polymorphism (MSAP) marker. The collective CG and CHG methylation levels of all 4 landraces of the domesticated form were significantly lower than those of the wild form. Interestingly, artificially transplanted ginseng plants recreated in both directions the methylation levels (at least in CHG) of their natural counterparts. The methylation differences between the 2 ginseng ecotypes were validated at 2 isolated MSAP loci bearing homology to a 5S rRNA gene or a copia retrotransposon. Our results implicate a link between epigenetic variation and habitat-induced phenotypic flexibility in Oriental ginseng.     

Salicylic acid and ethylene signaling pathways are involved in production of rice trypsin proteinase inhibitors induced by the leaf folder Cnaphalocrocis medinalis （Guenee）

The roles of signaling pathways in the production of trypsin proteinase inhibitors (TrypPIs) in rice infested by the leaf folder (LF) Cnaphalocrocis medinalis were studied. Infestation by LF increased TrypPI levels in the leaves of rice plants at the tillering, booting and flowering stages but decreased TrypPI levels at the ripening stage; TrypPI levels in rice stems did not increase at any developmental stage. Infestation by LF at the tillering stage systemically increased TrypPI levels in leaves but not in stems; it also enhanced salicylic acid (SA) levels in leaves and stems, and the ethylene level released from plants. However, LF infestation did not increase JA concentrations. Exogenous application of SA or ethylene enhanced TrypPI levels in the leaves and stems of plants at the tillering stage, whereas treatment with both SA and ethylene induced lower levels of TrypPIs than treatment with SA or ethylene alone, suggesting an antagonistic effect of SA and ethylene on TrypPIs induction. The results suggest that both SA and ethylene signaling pathways are involved in the production of TrypPIs in rice induced by LF; moreover, the antagonistic effect of SA and ethylene may explain the changes in TrypPI levels seen at different plant developmental stages and in different organs.     

低温-秋水仙素诱导甜瓜多倍体研究

以刚展开子叶的甜瓜植株为材料,采用低温-秋水仙素处理,植株全部成活,通过检测气孔-叶绿体的变化情况,选出4株定植于营养箱内,采收全部植株所结果实,保留种子并测量.采收期过后,用嫩芽叶尖为材料,对3株甜瓜进行染色体计数检测,检出1个四倍体.结果表明:低温-秋水仙素处理可以有效降低秋水仙素的毒害作用,提高植株成活率.植株后期,有由四倍体回复到二倍体的现象,说明在植株生长后期倍性稳定性有所改变.     

六齿双Schiff碱稀土配合物的结构及发光

稀土有机配合物作为重要的分子功能材料,由于具有光敏性强、发光效率高等特点,在生产生活的很多领域都具有广阔的应用前景.作为以分子发光材料和分子磁性材料为研究热点的Schiff碱稀土配合物,其合成、结构及其性能的研究吸引了大量国内外化学工作者的广泛关注.结合六齿Schiff碱稀土配合物结构及其性能的最新研究进展,对其新颖结...     

Eu3+掺杂ZnS纳米材料的制备及发光性能研究

低温水浴法制备不同掺杂浓度(摩尔百分比1％～7％)的ZnS:Eu纳米颗粒.采用X射线衍射仪对制备的样品进行物相分析,通过吸收和光致发光光谱对其进行了发光性能的研究.实验结果表明,所制备的样品均为立方相的ZnS:Eu,Eu3+占据了晶格的非对称反演中心,红光发射来源于Eu3+的5 D0→7 F2的跃迁.掺杂量为6％、热处...     

Gd2O3:Eu3+的制备及其在染料敏化太阳能电池中的应用

采用均匀沉淀法制备Gd₂O₃:Eu³⁺下转换发光粉, 对其光学特性进行了分析, 并将其应用到染料敏化太阳能电池中, 将电池吸收很弱的紫外光转化为可被染料吸收利用的可见光, 提高了电池的光电流; 通过Gd₂O₃:Eu³⁺的p-型掺杂效应, 使材料的费米能级上升, 增大了电池的开路电压; 同时, 发光层中稀土氧化物的存在不但能降低激发态染料往TiO₂ 导带注入电子的效率, 而且能在电极表面形成一个势垒抑制电荷复合, 对电池的光电流和光电压都有影响. 当Gd 与Ti 的摩尔比为6:100 时, 电池的光电转换效率达到最大值7.01%, 这比没掺发光粉的电池提高了17.4%.     

CaWO4:Eu3+,M3+(M=Tb,Sm,Bi,Dy)的水热合成及发光性能研究

利用水热合成法制备CaWO4∶Eu3+以及CaWO4∶Eu3+,M3+(M=Tb,Sm,Bi,Dy)系列钨酸盐基荧光粉,利用XRD表征产物CaWO4∶Eu3+(5%)的晶体结构,结果表明其结构和CaWO4的标准物相结构相似,为四方晶系结构;研究了CaWO4∶Eu3+的发光性能以及第二掺杂离子M3+(M=Tb,Sm,Bi...     

神经网络基于改进型粒子群算法的研究

提出一种基于被动聚集型粒子群优化算法来提高人工神经网络的性能,被动聚集是保持群体完整性的生物力量,该算法引入了生物学中被动聚集的概念,使得信息在种群各粒子间传播,保持种群的多样性。仿真实验表明:基于改进型粒子群优化算法的神经网络可以有效降低训练次数和均方误差。     

路径诱导系统中综合地图匹配算法的研究

地图匹配算法对于车辆路径诱导和实时轨迹回放具有重要的应用,为了提供连续、精确和可靠的车辆行驶路段位置,利用定位传感器输出车辆运行位置信息,结合高精度空间道路网络数据,提出新的综合地图匹配算法.该算法不受地理环境的约束,能有效地修正传感器的定位误差,提高车辆定位精度.实际道路测试证明,该算法比现有地图算法更高准确度和实时性,尤其是在十字路口有更好匹配效果.     

模拟高住低训对足球运动员血清瘦素和血脂的影响

探讨模拟高住低训对足球运动员体重、血脂及瘦素的影响.结果是实验前后实验组体重有显著性降低;血脂各项指标实验组和对照组都无显著性差异;瘦素含量实验组在第3周和第4周同入住前比较有显著性差异,但组间无显著性差异,对照组各时间点都无显著性差异.4周的间歇低氧和运动的双重刺激可明显降低足球运动员体重;对运动员血脂各项指标没有显著影响;可显著提高运动员的血清瘦素水平.