TRANSPORTATION AND DISTRIBUTION OF 14C-RESERVES ON DIFFERENT GENOTYPE WHEAT VARIETIES AFTER ANTHESIS

利用14CO₂对不同持绿性状的小麦品种进行花前示踪标记,研究持绿小麦的14C-储备物在花后的转运与分配规律。结果表明,小麦花前标记的14C-储备物在开花时80%～90%已储存于茎杆和颖壳中,仅有约10%～20%残留在叶片中;开花后这些储备物都向籽粒转运,成熟时籽粒中14C分配率约为20%～40%,茎杆与颖壳中含有约60%～80%,极少量残留在叶片中。持绿型小麦YM66的14C-储备物从叶片和茎杆中输出的快,成熟时籽粒含有40%的14C-储备物,这样比率高于对照品种XY22 和早衰品种WM6的14C-储备物。     

Comparisons among cultivars of wheat,hulless and hulled oats: Dry matter,N and P accumulation and partitioning as affected by N supply

A better understanding of the impact of fertilizer nitrogen (N) on biomass and N accumulation, and their partitioning into different plant components is needed to optimize crop yield and quality. A field experiment with spring wheat (Triticum aestivum), hulless (Avena nuda), and hulled (Avena sativa) oats was conducted for 3 years in Ottawa, ON, Canada, to determine the crop responses to N addition (0, 75, and 150 kg N ha^–1). Biomass, N, and phosphorus (P) accumulation and partitioning into different plant components were examined during the growth season. Lodging score was determined for all crops when it occurred and again at harvest. During the growth season, both hulless and hulled oats and the wheat cultivar showed almost similar patterns of N and P accumulation with maximum contents at late grain filling or at harvest. Plant N concentration was up to 60 g kg^–1 during the seedling stage, decreased gradually with advancing growth stages, and was lowest at harvest. Nitrogen treatments significantly increased plant N and P contents. At heading stage, N treatments enhanced dry matter (24%–45%), N (35%–135%), and P (27%–45%) contents in plant components (i.e., culm, leaf, and head), but also enhanced crop lodging, especially in oats. Both hulled and hulless oats had higher total plant N (5%–35%), N : P ratio, and dry‐matter content in leaf (6%–43%) and head (0%–129%) along with higher P (up to 27%) in culm than the wheat cultivar. The wheat cultivar accumulated greater dry matter and higher N content in kernels than both hulled and hulless oats at harvest. Both hulled and hulless oat cultivars exhibited similar lodging susceptibility to N addition (75 or 150 kg N ha^–1), produced lower dry weight and lower kernel N, and hence lower grain yield than the wheat cultivar. The larger vegetative dry‐matter accumulation at heading coupled with higher P content in culms under high‐N‐supply conditions may be related to severe lodging in oat cultivars.     

动物践踏干扰对生物结皮中微生物生态分布的影响

古尔班通古特沙漠作为北疆冬季牧场,普遍承受牲畜的践踏干扰,研究表明:动物践踏干扰导致各种类型生物结皮的覆盖度有不同程度的降低,干扰主要集中于结皮层(0～2 cm).微生物各类群对践踏干扰的反应具差异性,真菌与干扰的相关性最高,细菌和放线菌对干扰不敏感.践踏干扰改变了微生物各类群在垄间低地的数量垂直分布格局,但并未改变微生物区系组成.有机质对干扰不敏感,仍随土层加深而递减,在结皮层(0～2 cm)中与干扰率的相关性相对较高.     

隆回植烟土壤有机质含量及其影响因素空间变异性研究

为揭示隆回县烟区植烟土壤有机质含量分布状况及其影响因素,采用地统计学方法分析该烟区植烟土壤有机质含量分布及与影响其分布的土壤类型、土壤质地、pH等因素。结果表明：（1）隆回县烟区植烟土壤有机质含量较高,变幅为5.37~84.64 g/kg,变异系数为28.09%,处于适宜范围内的样本占21.09%,空间分布上呈现从北向南增加趋势。（2）不同乡镇之间的植烟土壤有机质含量差异达极显著水平,6个主产乡镇植烟土壤有机质含量属较高水平,且处于中等及低变异。（3）不同植烟类型土壤的有机质含量差异达极显著水平,红壤和黄壤的有机质含量属适宜水平,其他类型土壤的有机质含量属较高水平。（4）不同土壤质地的植烟土壤有机质含量差异达显著水平,烟区植烟土壤有机质含量平均在32.03~34.21 g/kg。（5）不同pH的植烟土壤有机质含量差异极显著,随pH升高而升高的趋势,且pH＞7.0的植烟土壤有机质含量较高。     

微波干燥与常规干燥中木材内含水率动态分布

以黑胡桃木材为对象,采用X射线扫描含水率分布测试方法,分析、比较了微波干燥与常规热风干燥过程中木材内部含水率动态分布规律.结果表明:在微波干燥和常规热风干燥过程中,木材内层含水率均高于表层,存在着整体性的内高外低的含水率梯度场;在接个微波干燥过程中,木材内部虽然出现了部分内层含水率低于外层的情况,存在着含水率分布的局部不均匀,但并未出现与常规热风干燥相反的含水率梯度;在微波干燥中,木材内部各层与表层含水率的差值随着干燥时间的延长逐渐降低.随着干燥过程的进行,常规热风干燥中木材芯层与表层含水率差呈现出先增加后减小的变化趋势.     

Using social media as a cost‐effective resource in the photo‐identification of a coastal bottlenose dolphin community

1. Bottlenose dolphins encountered around the Irish coast are considered part of a wide‐ranging coastal community; however, knowledge on the significance of the north of Ireland for this species is limited by a lack of dedicated effort.
2. Through social media, the opportunity now exists to gather large volumes of citizen science data in the form of high‐quality images, potentially extending the spatial and temporal scope of photo‐identification studies.
3. The purpose of this study was to investigate social media as a data resource for photo‐identification studies and to provide a preliminary assessment of bottlenose dolphins in the north of Ireland. Specifically, the study sought to examine the photo‐identification data for spatial clustering.
4. The study identified 54 well‐marked individuals and provided evidence of potential year‐round occurrence, with successful re‐sightings throughout the study period (2007–2016). There was a geographic concentration of re‐sightings along the north of Ireland, suggestive of interannual site fidelity. These results provide scientific rationale for strategically targeting the north of Ireland in future research on the Irish coastal community.
5. For effective conservation of the bottlenose dolphin it is imperative that scientific research, and resultant management objectives, consider wide‐ranging communities such as the Irish coastal community. Our research highlights data collection via social media as a cost‐effective and scientifically valuable tool in the photo‐identification of coastal cetaceans. We recommend that this method is used in research on low‐density and wide‐ranging coastal cetaceans.

     

云南稻种资源表现型分布地和分布民族分析

通过对分布于82个县市的1630份中国云南保存的地方稻种资源多种表现型现象进行分析,结果共有724份稻种资源是具有多种表现型现象的资源,即多型性资源,多型性资源的比例为44．0％,多型性系数X为1．75,多样性指数日为1．34,X与日的相关系数r=0．90。多型性资源的地理分布主要集中在思茅、临沦、版纳和德宏4个地州。以墨江、景洪、龙隆、永德、普洱、孟连和云县等7个县(市)为中心的地带,即云南多型性稻种资源主要集中分布在南部边缘及滇西南地区的野生稻分布区、稻种资源富集区和陆稻的主要种植区。分布地区是傣族、哈尼族、拉祜族和佤族等少数民族的主要聚居地。云南稻种资源的多种表现型现象与当地的地理和民族密切相关。     

江西近55年秋季降水时空分布及异常环流特征分析

为了研究江西近55年秋季(9—11月)降水的时间空分布及其异常环流形势特征,利用1961—2015年共55年86个气象站逐日降水资料及NCEP/NCAR月平均再分析资料,采用EOF、REOF分析、Morlet小波分析、趋势分析、M-K突变检验和合成分析等方法,研究江西近55年秋季降水的时间变化规律、空间分布特征及旱涝年的环流特征。结果表明:近55年来江西秋季降水呈弱增长趋势,在1981年、1984年和1987年发生突变,存在12~14年和2~4年的周期。空间场可分为全省一致型,南—北相反型和南北—中部相反型,其中全省一致型为主要空间分布形式。江西秋季降水可分为5个区域:一区(赣北中西部)、三区(赣中西部)和五区(赣中中东部)秋季降水呈增多趋势,二区(赣南)秋季降水呈减少趋势;四区(赣东北)秋季降水变化趋势较为稳定。5个区域秋季降水都存在2~4年左右的周期变化,还有多个区域都存在4~6年左右的周期变化,最长周期为14年左右。此外,江西秋季旱年,欧洲东部500 h Pa的大槽加强,江西850 h Pa处东北风距平中,降水偏少;反之,降水偏多。     

施氮量对稻麦干物质转运与氮肥利用的影响

为探讨太湖地区稻麦轮作农田适宜施氮量及氮素对干物质转运与氮肥利用的影响,于2007—2009年间在中国科学院常熟农业生态实验站建立田间定位试验。设置4个氮肥处理水平,分别用N0、N1、N2和N3表示。水稻各处理的施氮量分别为0、125、225和325kghm-2;小麦相应处理施氮量分别为0、94、169和244kghm-2(为稻季相应处理施氮量的75%)。结果表明,水稻施氮量超过225kghm-2,小麦施氮量超过169kghm-2后,产量增加不显著。水稻、小麦开花期干物质积累量均随施氮量的增加而增加,但花前营养器官干物质转运对籽粒贡献率均随氮肥用量增加而降低;氮肥农学效率与氮肥生理效率均随氮肥用量增加而降低,且N2与N3处理之间差异不显著;边际产量均随施氮量增加而下降,N3处理边际效益水稻平均低于3.1kgkg-1,小麦平均低于2.4kgkg-1。综上所述,无论水稻还是小麦,N2处理既能保证较高物质转运率,又能保证较高的氮肥利用效率与经济效益。     

播期对直播水稻产量、花后各器官干物质和氮素积累及转运的影响

为探究播期对直播水稻产量、花后干物质和氮素积累与转运的影响,以水稻品种白粳1号、长白9号和龙粳31号为供试材料,设置3个播期（SD1、SD2和SD3）,比较不同播期条件下3个品种的产量、抽穗期和成熟期各器官干物质及氮素积累与转运特点。3个品种抽穗期和成熟期各器官干物质及氮素积累量、抽穗至成熟期各器官干物质及氮素转运量和产量均表现为SD2>SD3>SD1。相关分析表明,产量与成熟期穗干物质及氮素积累量呈显著正相关,与叶片干物质和氮素转运量呈显著正相关。在本试验条件下,播期的推迟提高了3个品种有效穗数及结实率,进而提高了产量,同时促进了各器官物质转运量与转运率的提高。各品种SD2处理的产量及花后干物质、氮素积累量最高,SD2为适宜播期。