龟纹瓢虫（鞘翅目：瓢虫科）在中国是一种自然天敌昆虫，捕食范围广泛，常用于害虫治理。然而其在中国区域内遗传模式（遗传变异、种群结构和历史动态）还不清楚，从而阻碍了害虫生物防治的发展进程。种群遗传数据对于天敌生防过程中不同阶段策略的优化具有很大潜力。本研究通过收集中国区域内30个采样区域的462头龟纹瓢虫样本，采用23对微卫星和线粒体COI分子标记，开展了该种的群体遗传工作。微卫星数据显示龟纹瓢虫具有中等水平的遗传多样性，线粒体基因则显示出高水平的遗传多样性。与长江流域种群相比，黄河流域种群具有更高的遗传分歧。龟纹瓢虫中国种群未形成显著的地理种群结构，但存在群体分化的迹象，这可能与种群间频繁的基因交流有关。种群经历瓶颈后出现扩张，寄主植物——害虫——天敌之间的三级营养关系是种群扩张的重要因素。种群遗传研究在害虫生物防治过程中发挥着重要作用，本研究通过估测种群遗传多样性、种群遗传差异和推测种群历史动态，为有效利用天敌昆虫提供重要的遗传信息。

水稻种植区域广以及播种期不一等原因引起的生长季温度不适宜，导致了水稻产量和品质的降低。本研究目的是评估不同物候期温度对水稻产量及品质的影响，以获得长江流域水稻不同物候期适宜温度范围。因此，本研究以区域性品种为研究对象，在长江流域不同生态区开展播期试验,观测比较水稻生育进程、产量和品质的差异。结果表明不同播期以及不同生态区，水稻生育进程、产量和品质具有显著性差异，而这恰好与营养生长期（VT）及前20天灌浆期日平均温度（GT20）显著相关。此外，与VT和GT20相比，水稻幼穗分化期温度（RT）变化差异相对较小。因此，根据不同产量和品质的VT和GT20阈值，将本研究试验结果划分为4种情景（Ⅰ, Ⅱ, Ⅲ, 和 Ⅳ）。其中，情景Ⅰ可获得高的整精米产量和稻米品质；与情景Ⅰ相比，情景Ⅲ和 Ⅳ的整精米产量下降了30.1%和27.6%；情景Ⅱ整精米产量增加不显著，但是其垩白粒率和垩白度要比情景Ⅰ分别高出50.6%和56.3%。综上所述，情景Ⅰ下的VT和GT20组合方式（22.8℃<VT<23.9℃和24.2℃<GT20<27.0℃或3.9℃<VT<25.3℃和4.2℃<GT20<24.9℃），可用于指导长江流域水稻播期调整和水稻适宜品种的选取，以提高该区域的水稻产量和品质。

Received  6 June, 2017    Accepted  13 October, 2017

Soybean is a widely planted genetically modified crop around the world. However, it is still one of the most recalcitrant crops for genetic transformation due to the difficulty of regeneration via organogenesis and some factors that affect the transformation efficiency. The percentages of resistant bud formation and transient expression efficiency are important indexes reflecting the regeneration and transformation efficiency of soybean. In this study, the percentages of resistant bud formation and transient expression of β-glucuronidase (GUS) were compared after treatment with sonication or surfactant and co-treatment with both. The results showed that treatment with either sonication or surfactant increased the percentage of resistant bud formation and transient expression efficiency. The highest percentages were acquired and significantly improved when cotyledon node explants were co-treated with sonication for 2 s and surfactant at 0.02% (v:v) using two different soybean genotypes, Jack and Zhonghuang 10. The improved transformation efficiency of this combination was also evaluated by development of herbicide-tolerant soybeans with transformation efficiency at 2.5–5.7% for different genotypes, which was significantly higher than traditional cotyledonary node method in this study. These results suggested that co-treatment with surfactant and sonication significantly improved the percentages of resistance bud formation, transient expression efficiency and stable transformation efficiency in soybean.

The objective of this study was to determine the efficiency of different plant systems in capturing deep soil nitrate (NO3 -) to reduce NO3 - leaching in a field plot experiment using 15N labelling. The study was conducted on a calcareous alluvial soil on the North China Plains and the plant systems evaluated included alfalfa (Medicago sativa), American black poplar (Populus nigra) and cocksfoot (Dactylis). 15N-labelled N fertilizer was injected to 90 cm depth to determine the recovery of 15N by the plants. With conventional water and nutrient management, the total recovery of 15N-labeled NO3 --N was 23.4% by alfalfa after two consecutive growth years. The recovery was significantly higher than those by American black poplar (12.3%) and cocksfoot (11.4%). The highest proportion of soil residual 15N from the labeled fertilizer N (%Ndff) was detected around 90 cm soil depth at the time of the 1st year harvest and at 110-130 cm soil depth at time of the 2nd year harvest. Soil %Ndff in 0-80 cm depth was significantly higher in the alfalfa treatment than those in all the other treatments. The soil %Ndff below 100 cm depth was much lower in the alfalfa than those in all the other treatments. These results indicated that 15N leaching losses in the alfalfa treatment were significantly lower than by those in the black poplar and cocksfoot treatments, due to the higher root density located in nitrate labeling zone of soil profile. In conclusion, alfalfa may be used as a plant to capture deep soil NO3 - left from previous crops to reduce NO3 - leaching in high intensity crop cultivation systems of North China Plain.