当前远程实验教学的现状及对策

远程实验教学在远程教育中起着重要作用,是远程教育深入发展和构建学习型社会的需要,是实施素质教育、培养创新意识和实践能力的重要环节。但由于多种原因,远程实验教学在远程教育中还是一个薄弱环节,存在许多问题。要想促进远程教育的深入发展,提高远程实验教学的质量,就必需解决远程实验教学现状。     

Organic input quality is more important than its quantity: C turnover coefficients in different cropping systems

Annual C input to soil is a major factor affecting soil organic carbon (SOC) dynamics. However different types of C-sources can have different behaviour, in relation to their chemical characteristics and how they interact with soil. Root-derived C, in particular, should be more efficient than other organic materials as a result of the physicochemical and biological characteristics of the surrounding environment, leading to a reduction in the C decomposition rate.To test this hypothesis, we considered a long-term experiment underway in Northern Italy since 1962, comparing permanent meadow and 6 different crop rotations over a wide range of nutrient inputs, in both organic and inorganic forms. C inputs from amendments were measured and those from crops were calculated using allometric functions and crop and residues yields. The time evolution of SOC was studied through a single-pool, first-order kinetic model, allowing the estimation of humification coefficients for residues, roots, farmyard manure and cattle slurries.The highest value of the humification coefficient was estimated for farmyard manure, which confirmed its high efficiency in stabilising SOC content. Root C presented a humification coefficient 1.9 times higher than above-ground plant materials while slurries were intermediate, with a humification coefficient roughly half that of farmyard manure and even lower that of roots.The quality of C input thus seems of fundamental importance for evaluating the sustainability of different cropping systems in terms of SOC dynamics.     

海藻酸钠-聚乙烯醇交联微球制备参数优化研究

采用海藻酸钠和聚乙烯醇为包埋剂，选取交联时间、海藻酸钠和聚乙烯醇用量比（SA ∶ PVA）以及海藻酸钠和聚乙烯醇的总浓度为影响因素设计L49（52×7）正交实验，探讨包埋的最佳理化条件。以包埋材料的成球效果，包埋小球的硬度、弹性及微观结构为考察指标，比较包埋小球性能，探讨包埋条件。结果发现当SA ∶ PVA为7 ∶ 3，总浓度为4％，交联时间为24 h时包埋效果最佳。     

小麦耐热性基因的染色体定位和遗传效应分析

以中国春-HOPE染色体代换系为试验材料，利用细胞膜热稳定性和大田生产条件下高温胁迫两种方法，对与耐热性有关的基因进行了染色体定位。结果表明，无论是利用膜热稳定性方法，还是利用大田高温胁迫环境进行耐热性评价的方法，HOPE的2A，3A，2B，3B和4B染色体代换到中国春相应染色体后，均显著提高了中国春的耐热性，证明这些染色体含有与耐热性有关的基因。在大田高温胁迫环境条件下，HOPE的3D，4A，5A和5B染色体也表现与耐热性有关。利用单染色体代换系和不同耐热性代换系杂交组合，对耐热性的基因效应分析结果显示，HOPE2A染色体上的耐热性基因表现为显性效应，3A，2B，3A和4B染色体上的耐热性基因表现为加性效应；3B与4B，3A与2A，3B与2B以及这些染色体上的耐热性基因与2A染色体上的耐热性基因之间均可能存在互作效应。     

长期施肥对红壤磷组分及活性酸的影响

以12年的红壤长期肥力监测定位试验不同处理土壤为材料,研究了连续施肥对土壤磷组分、土壤对磷吸附解吸、土壤活性酸铝的影响。连续施用化学磷肥和化肥加有机肥,均可提高土壤全磷、无机磷数量。施用有机肥料,土壤中的磷以Ca-P和Al-P积累为主要表现形式,化学磷肥的施用能够提高土壤的全磷,并以Al-P增幅为最大,在所有处理中均表现为土壤O-P相对稳定。有机肥料处理土壤对外源磷的吸附强度明显少于施用化学磷肥和不施用磷肥的处理,有机肥料能够显著提高吸附磷的再利用,在NPKM处理中解吸磷占吸附磷的47.72%,M处理中占42.89%,其它处理中解吸磷占吸附磷数量一般少于8%。MNPK、M处理的PFI为2.51、2.69比N、NP处理4.53、4.37明显降低。在红壤旱地长期施用化学肥料,土壤交换性酸铝成倍增加,土壤酸化严重;施用有机肥料、有机肥料与化学肥料配合施用,土壤交换酸铝表现稳定。     

Use of multiparental inbred populations to determine allelic relationships of molecular markers

The assessment of polymorphism exhibited by molecular markers is an arduous but essential task that facilitates the use of molecular tools by breeders and geneticists. For that purpose, the value of a wheat composite population was assessed for characterizing the diversity of restriction fragment length polymorphism (RFLP) markers developed by INRA-Génoblé. The polymorphism of 13 genomic probes was measured over a set of 80 inbred lines randomly extracted by single-seed descent from a composite-cross of 16 wheat lines. The 13 probéenzyme combinations revealed 27 loci with codominant polymorphism. As many bands were so far unmapped, the segregational analysis of the progenies appeared very suitable for complex patterns, both in determining allelic relationships and in revealing linkage between loci. Allelic diversity, band sizes and chromosomal location assessed from nullisomic-tetrasomic lines are given for the 27 loci.     

Chromosomal location of fertility restoring genes for ‘wild abortive’ cytoplasmic male sterility using primary trisomics in rice

Summary Identification and location of fertility restoring genes facilitates their deployment in a hybrid breeding program involving cytoplasmic male sterility (CMS) system. The study aimed to locate fertility restorer genes of CMSWA system on specific chromosomes of rice using primary trisomics of IR36 (restorer), CMS (IR58025A) and maintainer (IR58025B) lines. Primary trisomic series (Triplo 1 to 12) was crossed as maternal parent with the maintainer line IR58025B. The selected trisomic and disomic F₁ plants were testcrossed as male parents with the CMS line IR58025A. Plants in testcross families derived from disomic F₁ plants (Group I crosses) were all diploid; however, in the testcross families derived from trisomic F₁ plants (Group II crosses), some trisomic plants were observed. Diploid plants in all testcross families were analyzed for pollen fertility using 1% IKI stain. All testeross families from Group I crosses segregated in the ratio of 2 fertile: 1 partially fertile+partially sterile: 1 sterile plants indicating that fertility restoration was controlled by two independent dominant genes: one of the genes was stronger than the other. Testcross families from Group II crosses segregated in 2 fertile: 1 partially fertile+ partially sterile: 1 sterile plants in crosses involving Triplo 1, 4, 5, 6, 8, 9, 11 and 12, but families involving triplo 7 and triplo 10 showed significantly higher X² values, indicating that the two fertility restorer genes were located on chromosome 7 and 10. Stronger restorer gene (Rf-WA-1) was located on chromosome 7 and weaker restorer gene (Rf-WA-2) was located on chromosome 10. These findings should facilitate tagging of these genes with molecular markers with the ultimate aim to practice marker-aided selection for fertility restoration ability.     

稻麦“双套”轻型简化栽培技术的研究及应用(Ⅰ) ——淮北地区稻棵套播麦的生育特点及栽培对策

系统论述了淮北地区稻棵套播麦播期提前，利于早发壮苗；群体大，高峰苗提前，利于足穗形成；幼苗发育进程提前，利于大穗形成的生育特点，及限制穗、粒、重三因素协调发展相关影响机理，提出了选用抗病品种、适期适量播种、“少食多餐”的平衡施肥方式、冬前保持地表土壤良好环境等配套轻型简化栽培技术，在生产实践中应用，取得了较好的经济效益和社会效益。     

60%吡福甲大豆超微粉体种衣剂的应用效果研究

通过对60%吡福甲大豆超微粉体种衣剂的试验,进一步验证了该种衣剂的防治效果。其对根腐病防效达74%,对孢囊线虫的防效达70%。与胶体种衣剂相比,减少农药使用量达53.4%,节约农药成本47%;与粉体种衣剂相比,减少农药使用量达37%,节约农药成本达49%。     

徐州地区日光温室保温性能的试验研究

分析了徐州地区冬季日光温室小气候的变化规律。针对当地日光温室冬季保温性能不理想的现状，从光照条件和温度条件两方面进行分析，对温室自身造成的保温性能不理想提出了改进意见，并在现有温室结构的基础上，通过选择最佳的揭盖帘时间，来提高冬季日光温室的保温性能。揭盖帘对比试验表明，揭盖帘时间选取恰当对室内温度影响较大，可以提高温室的保温性能。