本研究利用分布频率、变异系数、Shannon-weaver多样性指数、方差分析及聚类分析对“国家果树种质兴城梨、苹果圃”内保存的梨11个种456份梨资源和种间杂交品种114份共570份材料的39个果实表型性状进行多样性和性状差异的分析，通过相关性、主成分以及回归分析对梨种质资源进行综合评价指标筛选。主要结果如下: 梨种质果实28个字符型性状中检测到132种变异类型，多样性丰富；果实形状、萼片姿态、果肉类型、萼片状态、果锈位置、萼洼状态、风味和果实底色的多样性指数较高，分别为1.949、1.908、1.700、1.681、1.658、1.644、1.610和1.592。梨种质果实11个数值型性状中可滴定酸含量变异系数最高达128.43%，更能体现梨种质间的差异。梨5个栽培种（白梨、砂梨、秋子梨、新疆梨和西洋梨）种群间表型分化系数Vst（66.4%）高于种群内表型分化系数Vst（33.6%），种群间的变异是梨果实性状主要变异来源。系统聚类分析将包括川梨的6个栽培种389份资源分为6大类，组内具有一定的特征，组间存在差异，但并未完全按地域聚类，日韩砂梨和原产中国的砂梨聚在一起；白梨多数与砂梨聚在一起，少数与秋子梨聚在一起；秋子梨和西洋梨分别单独聚类；新疆梨和川梨均未单独聚类。采用主成分分析法和逐步回归分析法从39个性状中筛选出17个性状，决定总变异的99.3%，其中描述单果质量和可食率的性状3个（果实横径、果实纵径和果心大小）、形态特征和外观品质性状5个（果面盖色、果锈数量、果点明显程度、果实形状和果梗长度）和内在品质性状9个（果肉颜色、汁液、香气、风味、果肉质地、果肉类型、可溶性固形物含量、可滴定酸含量和内质综合评价），可作为梨种质资源综合评价指标。

木霉菌是一类非常重要且广泛被利用的根际促生真菌。本研究利用甜叶菊渣和基于病死畜禽酸解的氨基酸为原料固体发酵贵州木霉菌NJAU 4742，并评估了木霉菌固体菌种在不同的施用方式下（单独施用、与化肥联用和与有机肥联用）对玉米苗期的促生效应。通过单因素试验获得木霉菌固体发酵最高孢子密度为7×10⁹ CFU g^-1鲜重，最佳发酵条件为：甜叶菊渣：米糠比例为1：1、pH为3.0、氨基酸添加比例为6.67%、培养基含水量60%、接种比例10%、固体发酵厚度为3 cm和发酵时间为4天。木霉菌固体菌种单独施用和与化肥联用相比无木霉菌对照，都轻微提高了玉米苗期的生物量但均无显著性差异。然而，木霉菌固体菌种与有机肥联用相比有机肥，显著地提高了玉米苗期的生物量。另外，木霉菌的施用能够显著的改变玉米苗期的土体微生物群落。我们发现3个被鉴定为Trichoderma和Chaetomium属的OTUs在土体和根际都被木霉菌显著激发。值得注意的是，木霉菌固体菌种与有机肥联用显著激发了OTU_3（Phymatotrichopsis）进而促进了土壤的生产力。本研究表明甜叶菊渣是优质的木霉菌固体发酵原料，并且发现木霉菌固体菌种需与有机肥联用。

本研究2017年和2018年的种植密度为12.0×10⁴ 株 ha^-1，在施氮量为0-450 kg ha^-1范围内设置4种不同氮肥处理；2019年种植密度分别为7.5×10⁴和12.0×10⁴ 株 ha^-1，在施氮量为0-765 kg ha^-1范围内设置18种不同氮肥处理。通过测定不同处理下玉米生育期、绿叶的叶面积指数（LAI）、籽粒含水量和籽粒脱水率指标，阐明施氮量对玉米籽粒含水量的影响。结果表明，施氮量从0增加到765 kg ha^-1，玉米吐丝期推迟约1天，成熟期推迟约1-2天。在生理成熟期和生理成熟期后，不同施氮量处理下籽粒含水量极差为1.9-4.0％。随着施氮量的增加，生理成熟后玉米籽粒的脱水率降低，但施氮量与籽粒脱水率之间没有统计学意义。生理成熟期叶面积指数与生理成熟后籽粒脱水速率之间无显著相关性。总之，施氮对玉米生理成熟期和成熟后籽粒含水量均有影响，但不同施氮量对籽粒含水量的影响较小。以上结果表明，在生产中不需要考虑施氮对玉米籽粒含水量的影响。

Adhesions between different cells and extracellular matrix have been studied extensively in vitro, but little is known about their functions in testicular tissue counterparts. Spermatogonia and their companion somatic cells maintain a close association throughout spermatogenesis and this association is necessary for normal spermatogenesis. In order to keep the relative integrity of the testicular tissues, and to detect the development in vitro, culture testicular tissues in a threedimensional (3D) agarose matrix was examined. Testicular tissues isolated from 6.5 d postpartum (dpp) mouse were cultured on the top of the matrix for 26 d with a medium height up to 4/5 of the 3D agarose matrix. The results showed that in this 3D culture environment, each type of testicular cells kept the same structure, localization and function as in vivo and might be more biologically relevant to living organisms. After culture, germ cell marker VASA and meiosis markers DAZL and SCP3 showed typical positive analysed by immunofluorescence staining and RT-PCR. It demonstrated that this 3D culture system was able to maintain the number of germ cells and promote the meiosis initiation of male germ cells.

Studies have demonstrated that regulation of GDNF on male germline stem cells (mGSCs) mainly through Ras/Erk1/2, Src family kinase and PI3K/Akt signaling pathways, but the signaling pathways GDNF-mediated are different when the species and cell lines varied. Whether GDNF regulates self-renewal of mGSCs isolated from livestock has not been reported. Here, we purified mGSCs from dairy goat testis using mixed enzymes and fibronectin. Immunofluoresce staining revealed the cultured dairy mGSCs expressed Vasa, Nanos2, Ngn3, Tert, Dazl, Lin28, Oct4, CD49f, Stra8 and GFRa1, reflecting that these cells were mGSCs phenotype. Then we cultured these dairy goat mGSCs in different concentrations of GDNF (0, 5, 10, or 20 ng mL-1) to optimize the best concentration of GDNF to sustain the dairy goat mGSCs self-renewal, after that the inhibitor of PI3K (LY294002, 10 μmol L-1) was added to the medium which contains the optimal concentration of GDNF we obtained by experiments. The mGSCs cultured in different media were compared through the population doubling time (PDT), capacity of cell proliferation evaluated by PCNA and BrdU immunofluorescence staining, RT-PCR, QRT-PCR, Western blotting and flow cytometry. Results showed that 10 ng mL-1 was the optimal concentration of GDNF to maintain goat mGSCs self-renewal and GDNF up-regulates c-Myc transcription via the PI3K/Akt pathway to promote goat mGSCs proliferation. This study provides us an efficient model to study the mechanism in mGSCs proliferation and differentiation in goat, and has important implications in unveiling signaling pathways in livestock GSCs.

Mesenchymal stem cells (MSCs) derived from bone marrow are a well-characterized population of adult stem cells that can be maintained and propagated in culture for a long time with the capacity to form a variety of cell types. This study investigated the characteristics of dairy goat bone marrow MSCs (gMSCs) and their differentiation potential toward germ cells in vitro, and to test their potential in vivo, these cells were transplanted into seminiferous tubes of endogenous germ cells-depleted mouse models. The results showed that characteristic gMSC lines were established and a small population of gMSCs transdifferentiated into male germ cell-like cells which expressed Stra8 after induction with retinoic acid (RA), as analysed by reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescence. Further, we transplanted the gMSCs into endogenous germ cells-depleted mouse models. A variety of analysis demonstrated that gMSCs might differentiate into male germ cells and helped spermatogenesis in endogenous germ cells depleted mouse models at 30 d after transplantation. The gMSCs could be used as a potential source of cells for reproductive studies and a neoadjuvant therapy for the spermatogenesis anomaly. Moreover, these cells may offer a new strategy for male infertility and an alternative approach for production of transgenic animals.