不同类型雄性不育苎麻细胞学机理研究          下载免费PDF全文

薛丽君  邢虎成 《湖南农业大学学报(自然科学版)》2014,40(1):13-18

为探明苎麻雄性不育材料和可育材料在花芽分化和花药发育上的差异，选取不可育材料雄花萎缩型园青5号、花被不开裂型弯子苎麻、花粉不育型黄小叶和可育材料中苎1号(对照)，采用常规石蜡切片技术对其进行雄花花芽发育形态比较。结果表明：3种雄性不育苎麻花芽发育较可育苎麻中苎1号快，在花芽发育到0.3~0.5 cm时，已完成了雌、雄蕊的分化。参照可育苎麻材料的花芽分化和花药发育，推测3种雄性不育材料不育的原因分别为园青5号花芽在分化出花药和花丝后，花药不会继续分化形成花粉囊，而是变形萎缩甚至消失形成空腔；弯子苎麻在花粉分化阶段花被木质化严重；黄小叶花粉囊不破裂，花粉粒颜色逐渐变深，花丝发育异常。  相似文献   

三疣梭子蟹对蟹笼网目和刚性矩形逃逸口的逃逸行为比较          下载免费PDF全文

张健  马有成  裴占文  邱昱  吴建辉  石建高 《上海海洋大学学报》2022,31(3):801-811

为了解东海近海蟹笼逃逸口类型对三疣梭子蟹（Portunus trituberculatus）逃逸行为的影响，本研究使用红外水下摄像装备，对入笼的三疣梭子蟹在不同行为阶段对安装于侧网靠近笼底一侧的刚性矩形逃逸口（40mm高×200mm宽）和网目逃逸口（由2个位置较低的40mm×60mm和1个位置较高的60mm×60mm破目构成）的行为反应进行了观察。根据三疣梭子蟹探索、发现并接近、穿越企图和穿越逃逸口个体连续行为的4个阶段观察结果显示：相比刚性矩形逃逸口，三疣梭子蟹在网目逃逸口实验蟹笼中的探索行为持续时间更长；在笼底探索的个体能定位、发现并接近2种不同类型逃逸口，但发现并接近网目逃逸口时距离入笼的平均时间（P<0.01）和平均次数（P=0.061）均大于刚性矩形逃逸口；约85%发现并接近逃逸口的三疣梭子蟹企图穿越逃逸口，且在逃逸口类型之间没有显著差异；三疣梭子蟹在网目逃逸口前停留了更长的时间（P=0.006），且这一时间显著影响着个体是否企图逃逸的行为。所有个体均采用侧身姿态穿越逃逸口，对于刚性矩形逃逸口，个体甲高与逃逸口高度的关系是决定个体能否成功逃逸的关键因素；对于网目逃逸口，个体优先尝试穿越较低逃逸口，并最终全部逃逸。实验结果表明网目逃逸口可以作为蟹笼渔具逃逸装置，生物可降解材料应用可成为缓解蟹笼幽灵捕捞问题的技术手段之一。  相似文献   

Remote sensing of soil degradation: Progress and perspective     

《国际水土保持研究(英文)》2023,11(3):429-454

Soils constitute one of the most critical natural resources and maintaining their health is vital for agricultural development and ecological sustainability, providing many essential ecosystem services. Driven by climatic variations and anthropogenic activities, soil degradation has become a global issue that seriously threatens the ecological environment and food security. Remote sensing (RS) technologies have been widely used to investigate soil degradation as it is highly efficient, time-saving, and broad-scope. This review encompasses recent advances and the state-of-the-art of ground, proximal, and novel RS techniques in soil degradation-related studies. We reviewed the RS-related indicators that could be used for monitoring soil degradation-related properties. The direct indicators (mineral composition, organic matter, surface roughness, and moisture content of soil) and indirect proxies (vegetation condition and land use/land cover change) for evaluating soil degradation were comprehensively summarized. The results suggest that these above indicators are effective for monitoring soil degradation, however, no indicators system has been established for soil degradation monitoring to date. We also discussed the RS's mechanisms, data, and methods for identifying specific soil degradation-related phenomena (e.g., soil erosion, salinization, desertification, and contamination). We investigated the potential relations between soil degradation and Sustainable Development Goals (SDGs) and also discussed the challenges and prospective use of RS for assessing soil degradation. To further advance and optimize technology, analysis and retrieval methods, we identify critical future research needs and directions: (1) multi-scale analysis of soil degradation; (2) availability of RS data; (3) soil degradation process modelling and prediction; (4) shared soil degradation dataset; (5) decision support systems; and (6) rehabilitation of degraded soil resource and the contribution of RS technology. Because it is difficult to monitor or measure all soil properties in the large scale, remotely sensed characterization of soil properties related to soil degradation is particularly important. Although it is not a silver bullet, RS provides unique benefits for soil degradation-related studies from regional to global scales.  相似文献   

全国降水天气现象平行观测对比分析     

马宁  任芝花  王妍  刘娜  曹宁 《干旱区研究》2022,39(1):54-63

采用2017-08—2018-08全国2363个气象站降水现象平行观测对比观测数据,分别从数据完整性和准确性方面对雨、雪、毛毛雨、冰雹、雨夹雪5种降水现象自动观测数据进行了对比分析。结果表明:(1)雨、雪、毛毛雨现象的过程捕获率最高,分别为66.9%、69.2%、50.1%,冰雹的小时捕获率最高,为51.8%,雨夹雪的各捕获率指标均较低。(2)毛毛雨的漏报率最高为65.9%,雪的漏报率次之为35.6%,冰雹的漏报率最低为16.2%;毛毛雨、雨的错报率较低,雨夹雪和冰雹的错报率较高,毛毛雨、冰雹错报为雨的比例较高,雨错报成毛毛雨的比例较高,雪错报成毛毛雨和雨的比例较高,而雨夹雪则常常是毛毛雨、雨、雪交替出现;毛毛雨和冰雹的空报站点较多。(3)降水现象仪对降水现象的识别可达到分钟级,但与人工观测降水现象相比,存在漏报、错报和空报情况,需要在气象站数据采集端进行质量控制,不断优化降水现象识别算法,并结合其他天气要素进行降水现象综合判识,以提高仪器对降水天气现象的捕获率,降低漏报率、错报率和空报率。  相似文献   

甘草产香内生真菌RP2的初步鉴定及挥发性成分分析     

尤梦瑶  闫佳佳  万璐  张赫  郑春英 《中国农学通报》2022,38(12):138-145

为了开发甘草内生真菌RP2次生代谢产物的资源,丰富挥发性香味成分的获取途径,以甘草内生真菌RP2为研究对象,采用形态学观察及ITS序列分析法对其进行菌种鉴定,通过气相色谱-质谱联用技术(GC-MS)对甘草内生真菌RP2挥发性成分进行分析。甘草内生真菌RP2经鉴定为尖孢镰刀菌(Fusarium oxysporum)。在甘草内生真菌RP2发酵液中分离并鉴定出11种挥发性成分;在甘草内生真菌RP2菌丝体中分离并鉴定了6种挥发性成分。甘草内生真菌RP2挥发性成分中含有多种现有工业生产中广泛应用的挥发性香味成分,如2-苯基乙醇等。本研究对开发利用甘草内生真菌RP2具有重要意义。  相似文献   

Development of the Auburn Induction Scale for evaluating induction quality in dogs     

《Veterinary anaesthesia and analgesia》2022,49(6):608-614

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Hand-feel soil texture observations to evaluate the accuracy of digital soil maps for local prediction of soil particle size distribution: A case study in Central France     

Anne C. RICHER-de-FORGES  Dominique ARROUAYS  Laura POGGIO  Songchao CHEN  Marine LACOSTE  Budiman MINASNY  Zamir LIBOHOVA  Pierre ROUDIER  Vera L. MULDER  Herv&#; N&#;D&#;LEC  Guillaume MARTELET  Blandine LEMERCIER  Philippe LAGACHERIE  Hocine BOURENNANE 《土壤圈》2023,33(5):731-743

Digital maps of soil properties are now widely available. End-users now can access several digital soil mapping (DSM) products of soil properties, produced using different models, calibration/training data, and covariates at various spatial scales from global to local. Therefore, there is an urgent need to provide easy-to-understand tools to communicate map uncertainty and help end-users assess the reliability of DSM products for use at local scales. In this study, we used a large amount of hand-feel soil texture (HFST) data to assess the performance of various published DSM products on the prediction of soil particle size distribution in Central France. We tested four DSM products for soil texture prediction developed at various scales (global, continental, national, and regional) by comparing their predictions with approximately 3 200 HFST observations realized on a 1:50 000 soil survey conducted after release of these DSM products. We used both visual comparisons and quantitative indicators to match the DSM predictions and HFST observations. The comparison between the low-cost HFST observations and DSM predictions clearly showed the applicability of various DSM products, with the prediction accuracy increasing from global to regional predictions. This simple evaluation can determine which products can be used at the local scale and if more accurate DSM products are required.  相似文献