莴苣花叶病毒北京分离物基因组3′末端序列分析

笔者通过RT-PCR方法对LMV北京分离物（LMV-BJ）基因组3＇端1620nt的核苷酸片段进行了克隆和序列分析（GenBank登录号为EF423619）。所获片段含有NIb基因3＇端的574nt,编码NIb C-端190个氨基酸;完整的CP基因,全长为834nt,编码一个由277个氨基酸组成的分子量约为30kDa的结构蛋白;3＇非编码区含有209nt。通过序列分析软件将LMV-BJ与已经报道的法国分离物O（X97704）、法国分离物E（X97705）,美国分离物（X65652）,巴西分离物（AJ278854）和余杭分离物（AJ306288）基因组3＇末端和CP基因的核苷酸序列与氨基酸序列分别进行了比较。     

四种鸢尾属植物种子休眠和萌发研究

燕子花(Iris laeviga ta)、玉蝉花(Iris ensa ta)、溪荪(Iris sanguinea)、黄菖蒲(Iris pseudacorus)是鸢尾科4种喜水湿植物。经萌发实验证明,除溪荪种子没有休眠外,其它3种种子都有休眠。经去除种皮、低温沙藏、赤霉素处理和胚培养4种处理,证明燕子花、玉蝉花、黄菖蒲中抑制种子萌发的主要因素是胚乳。不同种打破休眠的有效方法不同,其中50 mg/L GA3处理可提高黄菖蒲种子的发芽率,达到84.4%,而低温沙藏30 d可使玉蝉花种子的发芽率达到94.4%,低温沙藏90 d则可提高燕子花的发芽率达到87.8%。     

二级缓释熏蒸在六面密闭粮堆中的应用

通过对六面密闭麻袋包装小麦粮堆分别采用二级缓释熏蒸、常缓熏蒸和缓释熏蒸的施药方法进行对比试验。结果表明,采用二级缓释熏蒸保持PH3有效浓度时间最长、Ct值最大,熏蒸效果最理想。采用5.3 g/m剂量,全年只熏蒸1次即可保持粮堆全年无害虫。     

Hydroxamic acid content of triticum species

Summary Fifty-five accessions of Triticum species were analyzed for content of hydroxamic acids (Hx), a natural resistance factor against various organisms. Hx were found in all accessions analyzed. Extreme values were found in wild diploid species: highest in T. speltoides (16.0 mmol/kg fr. wt) and lowest in T. tauschii (0.21). Modern polyploid wheats sharing the same genome did not show substantial variations in Hx levels. The data suggest possible sources of high Hx levels for wheat breeding programs.     

Effects of elevated carbon dioxide and ozone on potato tuber quality in the European multiple-site experiment ‘CHIP-project’

Potato (Solanum tuberosum L cv. Bintje) was exposed to ambient and elevated carbon dioxide (CO₂), to ambient and elevated ozone (O₃) and to elevated levels of both gases during two growing seasons, 1998 and 1999. Experiments in open-top chambers (OTC) were carried out in Finland, Sweden, Ireland, United Kingdom, Germany and Belgium and a FACE (Free Air Carbon dioxide Enrichment) experiment was carried out in Italy. In OTCs the plants were grown under ambient CO₂ concentrations or with 550 and 680 μl l⁻¹ CO₂ alone or in combination with ambient or elevated O₃ concentrations (target seasonal mean of 60 nl l⁻¹ 8 h per day). In the FACE systems the plants were exposed to ambient or 550 μl l⁻¹ CO₂. In the OTC experiments the reducing sugar content of potato tubers decreased significantly with increased concentration of O₃. The starch content of potato tubers decreased, with negative impact on tuber quality, but the ascorbic acid concentration increased as a function of the AOT40 (The sum of the differences between hourly ozone concentration and 40 nl l⁻¹ for each hour when the concentration exceeds 40 nl l⁻¹ during a relevant growing season). However, simultaneous exposure to elevated CO₂ counteracted the ozone effect. With increase in the CO₂ exposure, glycoalkaloid and nitrate concentrations decreased yielding improved quality, while the citric acid concentration decreased causing a higher risk for discoloration after cooking. The amount of dry matter and starch increased significantly in the FACE experiment.     

利用相同来源F2:3和BC2S1群体定位玉米生育期QTL

以普通玉米自交系丹232和爆裂玉米自交系N04为亲本构建259个F2:3和220个BC2S1家系群体,利用SSR标记构建分子标记遗传图谱,利用复合区间作图方法对4个生育期性状进行QTL定位和效应分析。利用F2:3群体共检测到4个抽雄期QTL、6个吐丝期QTL和3个散粉期QTL。单个QTL可解释的表型变异为6.7%~18.4%,可解释的表型总变异为28.9%~50.3%,11个QTL的增效基因来自生育期较长的亲本丹232,其余2个QTL的增效基因来自生育期较短的亲本N04;BC2S1群体检测到8个与4个生育期性状相关的QTL,单个QTL可解释的表型变异为4.5%~11.6%,可解释的表型总变异为13.2%~18.5%,增效基因来自两个亲本的QTL为3个和5个。两类群体检测出QTL的数目、位置、效应和贡献率均存在较大差异,主要原因在于BC2S1群体抽样选择所引起的群体结构差异,F2:3群体显示出较高的QTL检测能力,但回交育种过程中应慎重依据F2:3群体QTL定位结果进行标记辅助选择(MAS)。     

Influence of indoor temperature on equivalent thermal resistance of green roof

绿化屋顶在节能设计中以附加当量热阻增大屋顶总热阻值,有效减少由屋顶进入室内的热量,降低室内空气温度。但根据已有的实验研究,绿化屋顶隔热特性与室内气温是耦合关系,随室内气温的变化,绿化屋顶会呈现出不同的隔热特性。用实验测试与数值模拟相结合的方法,分析在不同室内气温下绿化屋顶、参照屋顶与等效保温屋顶内表面温度与热流的变化。结果表明：室内气温会显著改变绿化屋顶的隔热性能,其当量热阻为与室内温度正相关的变量。在被动式建筑中,绿化屋顶更能充分发挥隔热功效,且具有不向室内传热的特性。     

GA3处理对仙客来种子萌发的影响

本实验以哈里奥斯系列‘2010’、‘2015’品种的仙客来种子为材料,研究了GA3处理对仙客来种子萌发的影响.结果表明：不同GA3处理均促进了仙客来种子的萌发,提高了种子的发芽率,但不同品种间对GA3处理的反应不同.在18℃下,‘2015＇种子最适处理浓度为10 mg/L,时间为4 h;‘2010＇种子GA3处理最适浓度为400mg/L,最佳时间为2 h.     

Modelling Biomass Accumulation and Partitioning in Chickpea (Cicer arietinum L.)

Quantitative information regarding biomass accumulation and partitioning in chickpea (Cicer arietinum L.) is limited or inconclusive. The objective of this study was to obtain baseline values for extinction coefficient (K_S), radiation use efficiency (RUE, g MJ^?1) and biomass partitioning coefficients of chickpea crops grown under well‐watered conditions. The stability of these parameters during the crop life cycle and under different environmental and growth conditions, caused by season and sowing date and density, were also evaluated. Two field experiments, each with three sowing dates and four plant densities, were conducted during 2002–2004. Crop leaf area index, light interception and crop biomass were measured between emergence and maturity. A K_S value of 0.5 was obtained. An average RUE of 1 g MJ^?1 was obtained. Plant density had no effect on RUE, but some effects of temperature were detected. There was no effect of solar radiation or vapour pressure deficit on RUE when RUE values were corrected for the effect of temperature. RUE was constant during the whole crop cycle. A biphasic pattern was found for biomass partitioning between leaves and stems before first‐seed stage. At lower levels of total dry matter, 54 % of biomass produced was allocated to leaves, but at higher levels of total dry matter, i.e. under favourable and prolonged conditions for vegetative growth, this portion decreased to 28 %. During the period from first‐pod to first‐seed, 60 % of biomass produced went to stems, 27 % to pods and 13 % to leaves. During the period from first‐seed to maturity, 83 % of biomass was partitioned to pods. It was concluded that using fixed partitioning coefficients after first‐seed are not as effective as they are before this stage. Environmental conditions (temperature and solar radiation) and plant density did not affect partitioning of biomass.