Combined application of chemical fertilizers with organic amendments was recommended as a strategy for improving yield, soil carbon storage, and nutrient use efficiency.  However, how the long-term substitution of chemical fertilizer with organic manure affects rice yield, carbon sequestration rate (CSR), and nitrogen use efficiency (NUE) while ensuring environmental safety remains unclear.  This study assessed the long-term effect of substituting chemical fertilizer with organic manure on rice yield, CSR, and NUE.  It also determined the optimum substitution ratio in the acidic soil of southern China.  The treatments were: (i) NPK₀, unfertilized control; (ii) NPK₁, 100% chemical nitrogen, phosphorus, and potassium fertilizer; (iii) NPKM₁, 70% chemical NPK fertilizer and 30% organic manure; (iv) NPKM₂, 50% chemical NPK fertilizer and 50% organic manure; and (v) NPKM₃, 30% chemical NPK fertilizer and 70% organic manure.  Milk vetch and pig manure were sources of manure for early and late rice seasons, respectively.  The result showed that SOC content was higher in NPKM₁, NPKM₂, and NPKM₃ treatments than in NPK₀ and NPK₁ treatments.  The carbon sequestration rate increased by 140, 160, and 280% under NPKM₁, NPKM₂, and NPKM₃ treatments, respectively, compared to NPK₁ treatment.  Grain yield was 86.1, 93.1, 93.6, and 96.5% higher under NPK₁, NPKM₁, NPKM₂, and NPKM₃ treatments, respectively, compared to NPK₀ treatment.  The NUE in NPKM₁, NPKM₂, and NPKM₃ treatments was higher as compared to NPK₁ treatment for both rice seasons.  Redundancy analysis revealed close positive relationships of CSR with C input, total N, soil C:N ratio, catalase, and humic acids, whereas NUE was closely related to grain yield, grain N content, and phenol oxidase.  Furthermore, CSR and NUE negatively correlated with humin acid and soil C:P and N:P ratios.  The technique for order of preference by similarity to ideal solution (TOPSIS) showed that NPKM₃ treatment was the optimum strategy for improving CSR and NUE.  Therefore, substituting 70% of chemical fertilizer with organic manure could be the best management option for increasing CSR and NUE in the paddy fields of southern China

施肥是提升土壤肥力促进作物增产的有效措施，长期不同施肥对土壤培肥的效果差别很大，依托中国农科院红壤实验站双季稻田连续38年不同施肥定位试验，研究了7种不同施肥处理CK（不施肥）；NPK（化学氮、磷、钾肥料）；M（腐熟牛粪）；NPKM（化学氮、磷、钾和牛粪）；NPM（化学氮、磷和牛粪）；NKM（化学氮、钾和牛粪）；PKM（化学磷、钾和牛粪）对水稻产量、稻田土壤肥力与养分表观平衡的影响。结果表明，各处理水稻年均产量由高到低为NPKM、NPM、NKM、PKM、M、NPK、CK，范围在6214-11562 kg hm²。长期有机无机配施处理（NPKM、NPM、NKM、PKM）较NPK的增产率分别为：22.58%、15.35%、10.53%、4.41%。长期有机无机配施处理（NPKM、NPM、NKM、PKM）的土壤有机碳、全氮、有效氮、速效钾含量均显著高于CK和NPK，其中有机肥配施氮磷肥处理的NPKM、NPM、PKM土壤全磷和有效磷含量显著高于CK、NPK；NPKM处理的水稻年均产量（11562 kg hm²）、有机碳（20.88 g kg^-1）、土壤全氮（2.30 g kg^-1）、全磷（0.95 g kg^-1）、全钾（22.5 g kg^-1）、有效磷含量（38.94 mg kg^-1）均为各处理中最高，NKM处理土壤碱解氮含量（152.4mg kg^-1）和速效钾含量（151.00 mg kg^-1）为各处理最高。氮、磷施用量的增加导致土壤中氮、磷养分出现盈余，但NPKM处理相比其他处理能够有效降低盈余量；各处理土壤中钾素均表现为亏缺。相关性分析表明土壤SOC、TN、AN、TP、AP含量均与水稻产量显著相关（P<0.05），相关系数分别为0.428、0.496、0.518、0.501和0.438。本研究表明，相比单施化肥，长期有机肥配施化肥通过提升土壤肥力，促进土壤养分平衡，显著增加水稻产量，其中有机肥配施氮磷钾肥(NPKM)对于土壤肥力和水稻产量的提升效果最好。

黄瓜是研究花发育的重要模式作物，控制花发育相关的基因通常具有特异的时空表达模式，原位杂交技术（ISH）被广泛应用在分析黄瓜茎端分生组织（SAM）和花芽组织（FM）的基因时空表达模式上。原位杂交的常用方法是石蜡原位杂交，然而石蜡原位杂交中组织包埋周期长，RNA容易降解，导致信号减弱。本研究基于石蜡原位杂交进行了优化建立了碳蜡原位杂交方法，具有操作简便，灵敏度高的优点。该方法一是使用低熔点的碳蜡，RNA保存好；二是结合了整体原位杂交的方法，在溶液中处理组织切片，解决了碳蜡不易粘片的问题。在文章中，利用碳蜡原位杂交方法，我们在黄瓜的茎端分生组织（SAM）和花芽组织（FM）中检测了CLV3和WUS1基因的表达模式，实验结果与前期研究结果一致，而且该方法比石蜡原位杂交周期缩短4-5天，信号强。同样地，该方法也成功用于拟南芥中CLV3和WUS1的表达模式分析，表明碳蜡原位杂交方法在大多数物种中具有普遍适用性。

植物的单性花可以有效促进异交，研究单性花的形成和调控机制对于理解植物性别决定过程有重要意义，也为研究者和农业生产者利用杂种优势提供便利。在黄瓜杂交制种过程中，将只开雌花的株系种植于只开雄花的株系周围，可以显著降低制种成本。筛选更多不同基因背景的只开雄花的材料，将增加可用于育种的种质资源。我们基于前期构建的EMS诱变自交系材料“406”的突变体库，发现了一个新的只开雄花的突变体。遗传分析、全基因组重测序和分子标记辅助验证表明，ACS11基因上发生的异义突变第301位丝氨酸（Ser）变为苯丙氨酸（Phe）导致全雄株的产生。体外酶活性测定表明，此突变导致酶活性完全丧失。本研究为黄瓜雄性亲本选育提供了新的种质资源，并为 ACS 酶的催化机理提供了新的认识。

本研究鉴定出棉花SLs信号传导途径基因GhMAX2，研究了其在陆地棉生长和株型形成中的作用。生物信息学分析表明GhMAX2蛋白主要由一个α-螺旋和一个无规卷曲组成，含有大量富含亮氨酸的重复序列。GhMAX2基因在根、茎、花和20天的纤维中高表达，GhMAX2启动子驱动的GUS在拟南芥根、主花序、花和角果中表达。亚细胞定位结果显示GhMAX2定位于细胞核。在拟南芥max2-1突变体中异源表达GhMAX2，可以回复至野生型的表型，表明MAX2的功能在陆地棉和拟南芥之间高度保守。此外，棉花中GhMAX2基因的敲低表达可导致植株高度降低，生长缓慢，节间缩短，纤维变短。上述结果表明，GhMAX2可能在棉花的生长、株型形成以及纤维伸长中发挥重要功能。综上，本研究主要揭示了GhMAX2介导的SL/KAR信号在棉花中的功能，为今后棉花新品种培育提供了理论依据。

 

该研究系统阐述了长期不同施肥对土壤剖面SOC和N库的影响，通过冗余分析了SOC团聚体组分及影响因素，三维表面分析深入理解剖面SOC和N库对作物产量的影响。与化肥处理相比，长期施用有机肥通过增加表土层 (0–20 cm）SOC输入、SOC储量、TN储量和土壤pH值来提高作物产量。不同施肥处理的SOC团聚体组分存在差异，所有处理SOC团聚体组分高低依次为矿物结合有机碳（mSOC）>粗自由颗粒有机碳（cfPOC）>物理保护有机碳（iPOC）>细自由颗粒有机碳（ffPOC）。施用有机肥处理的所有SOC组分含量均显著高于化肥处理。在不同SOC团聚体组分中，ffPOC对不同施肥处理的敏感性最高。单施有机肥（M）和有机无机肥配施（NPKM）显著提高了表层（0-20 cm）SOC和TN含量，与化肥处理相比，M和NPKM处理降低了深层土壤（80-100 cm）中的SOC和N含量，有利于减少养分垂直流动，从而减少养分的淋溶损失。

促进农户经济作物种植能否显著的增加其家庭福利一直是粮食政策的焦点。本研究首先探讨了农户商业化种植食用豆行为的影响因素，并进一步分析食用豆商业化生产如何改善了农户的经济福利。本文使用了2018年至2019年期间收集的848户农户家庭数据集，通过应用Heckman两步法估计了农户家庭商业化食用豆生产的影响因素，并采用内生处理回归（ETR）方法检验了商业化食用豆种植对农户家庭经济福利的影响。结果表明，食用豆市场价格（农户销售价格）、农业技术服务、农户获得贷款途径，以及政府补贴等因素显著的促进了农户商业化的食用豆生产，而生产成本增加和对气候变化风险的认知限制了食用豆农户商业化生产。总体而言，商业化的食用豆生产显著的增加了农户家庭农业收入，但对农户家庭非农收入的影响有限。这一研究结果进一步表明，通过促进农户家庭进行商业化的经济作物生产，并降低农户农产品市场准入的政策可以显著提高经济作物（比如食用豆）农民家庭的经济福利。

死体营养型病原菌立枯丝核菌是造成各种作物产量损失的破坏性真菌之一。在水稻上，该病原菌可侵染水稻叶鞘叶片引起纹枯病的发生，造成严重的产量损失和品质下降。目前，人们对植物如何应对该病原菌入侵的防御机制还知之甚少。为了探索水稻响应纹枯病菌侵染的分子机制，本研究以抗纹枯病水稻品种YSBR1为材料，采用蛋白质组学同位素相对标记与绝对定量技术（iTRAQ），筛选和分析纹枯病菌侵染前后的差异积累蛋白（differentially accumulated proteins, DAPs）。通过比较分析，总计鉴定到319个DAPs，其中161个上调积累、158个下调积累。GO和KEGG功能富集分析结果显示，这些DAPs涵盖了多种功能途径，其中大部分位于细胞氧化还原稳态、糖酵解过程、三羧酸循环、苯丙烷生物合成、光合作用、叶绿素生物合成过程及病程相关蛋白这七个信号途径。进一步采用荧光定量PCR方法，对从7个信号途径中各随机选择的2个DAPs基因进行转录水平验证，结果不仅证实本研究中筛选到的DAPs具有较高的可靠性，而且进一步证明这些途径确实参与水稻对纹枯病菌的侵染响应。结合这7个信号途径中的相关基因或蛋白的功能信息，认为其在水稻抵御纹枯病菌侵染过程中具有重要作用。另外，我们发现所有参与光合作用和叶绿素生物合成途径的DAPs及部分参与苯丙烷生物合成途径的DAPs在受到纹枯病菌侵染后均显著下调积累，暗示纹枯病菌侵染时可能优先攻击水稻的光合系统加速细胞死亡，进而通过抑制水稻体内苯丙烷的生物合成等信号削弱寄主防御反应，帮助其快速侵染和扩展。本研究结果为进一步解析水稻-纹枯病菌间的互作机制提供更多有价值的数据信息和新的视角。

头孢喹肟是动物专用的第四代头孢菌素类药物，对大肠杆菌和金黄色葡萄球菌均有较好的作用效果。本研究旨在建立头孢喹肟对大肠杆菌和金黄色葡萄球菌的野生型折点（wild-type cut-off, CO_WT）和药动/药效学折点（pharmacokinetic/pharmacodynamic, CO_PD），以期为临床细菌耐药性监测提供数据指导。采用微量肉汤稀释法测定2014至2018年期间广东省分离的210株猪源大肠杆菌和160株猪源金黄色葡萄球菌对头孢喹肟的最低抑菌浓度（minimum inhibitory concentration, MIC），结果表明头孢喹肟对大肠杆菌的MIC₅₀（能抑制50%细菌生长的最低药物浓度和MIC₉₀（能抑制90%细菌生长的最低药物浓度）分别是0.06 μg mL^-1和0.25 μg mL^-1；对金黄色葡萄球菌的MIC₅₀和MIC₉₀分别是0.5 μg mL^-1 和1 μg mL^-1。统计学分析方法和ECOFFinder程序计算结果表明头孢喹肟对大肠杆菌和金黄色葡萄球菌的野生型折点分别为0.125 μg mL^-1和2 μg mL^-1。大肠杆菌和金黄色葡萄球菌对头孢喹肟的耐药率分别为11.9％和6.25％。基于5000次循环的蒙特卡洛计算结果显示在临床推荐给药剂量下（2 mg kg^-1,每天给药2次，连续给药3天），头孢喹肟对大肠杆菌和金黄色葡萄球菌的药动/药效学折点值均为0.25 µg mL^-1，表明在当前推荐剂量下可对MIC ≤ 0.25 μg mL^-1的大肠杆菌和金黄色葡萄球菌实现90％以上的有效治疗。当前的给药方案对金黄色葡萄球菌引起的感染不能取得理想的治疗效果，将头孢喹肟给药剂量调整为4.5 mg kg^-1时，能对MIC₉₀ = 1 μg mL^-1的金黄色葡萄球菌引起的感染实现90%以上的有效治疗。本研究对于临床上头孢喹肟对猪源大肠杆菌和金黄色葡萄球菌的耐药性监测和用药指导有重要意义。

本文考察了中国农户参与合作社和农业技术采纳行为对其经济福利的影响。基于中国15个省份396个农户的微观调查数据，采用双选择模型(DSM)修正由可观测和不可观测因素引起的样本选择偏差，并采用倾向评分匹配(PSM)方法进行反事实分析，以计算农业收入差异。研究结果表明，相比不参与农民合作社、不采纳农业技术而言，农户参与农民合作社、采纳农业技术的农业收入分别增加2.77%和2.35%。有趣的是，与高收入农户相比，低收入农户参与农民合作社、采纳农业技术的农业收入分别高出5.45%和4.51%，且影响更为显著。这表明农民合作社和农业技术能够提升农户经济福利。在此基础上，本文进一步提出了相应的政策建议。

后药浴剂是预防奶牛乳腺炎的有效手段之一，本研究旨在探究一种基于聚维酮碘-壳聚糖的乳头成膜药浴剂对奶牛乳腺炎的预防效果，主要包括以下几个方面：一、壳聚糖对奶牛乳腺炎致病菌抑菌效果的研究：利用最低抑菌浓度实验考察不同分子量壳聚糖（5，50，150，350 kDa）对六种常见乳腺炎致病菌的抑菌效果，结果显示50 kDa的壳聚糖对六种致病菌的抑菌效果最好，将其应用于下一步的药浴剂制备；二、壳聚糖添加量对成膜药浴剂抑菌性能的影响：利用药敏实验考察不同壳聚糖添加量（0.0, 0.5, 1.0, 1.5%）对六种常见乳腺炎致病菌的抑菌效果，结果显示含4%聚维酮碘及1%壳聚糖的成膜药浴剂对大肠杆菌、金黄色葡萄球菌、无乳链球菌、蜡样芽胞杆菌的抑菌效果要显著大于含4%聚维酮碘的成膜药浴剂（P<0.05）；三、成膜药浴剂临床效果研究-乳区实验：选取47头健康中国荷斯坦牛进行为期56天的乳区对比实验，奶牛左侧2个乳区后药浴使用含4%聚维酮碘及1%壳聚糖的成膜药浴剂，右侧2个乳区后药浴使用10%聚维酮碘。在试验开始时（0天）和第28、56天时采集奶样，进行乳成分和乳中体细胞数（Somatic Cell Count，SCC）测定，同时针对SCC高于200,000个/mL的奶样进行致病菌的分离鉴定。结果表明：左侧乳区和右侧乳区奶样在0、28、56天时SCC及乳成分等指标均无显著差异（P>0.05）。四、成膜药浴剂临床效果研究-牛群实验：选取139头健康中国荷斯坦奶牛进行为期56天的群体对比实验，其中对照组67头，实验组72头。对照组后药浴使用10%聚维酮碘，实验组后药浴使用聚维酮碘-壳聚糖成膜药浴剂。结果表明：56天时，实验组的隐性乳腺炎发病率比对照组降低了29% (P<0.05)。在实验组内，第56天的隐性乳腺炎发病率低于0天 (P<0.05)。此外，实验组和对照组奶样在0、28、56天时SCC、乳成分指标和临床乳腺炎发病率均无显著差异（P>0.05）。微生物分离鉴定实验结果表明基于聚维酮碘-壳聚糖的乳头成膜药浴剂可有效预防由肺炎克雷伯菌、铜绿假单胞菌和弗格森大肠杆菌引起的隐性乳腺炎。综上所述，含4%聚维酮碘及1%壳聚糖的成膜药浴剂预防奶牛隐性乳腺炎的效果要优于10%聚维酮碘，该研究为扩大壳聚糖在奶牛乳腺炎防治方面的应用，开发壳聚糖相关的绿色兽药产品提供了科学的理论依据。

Azospirillum brasilense与Pseudomonas fluorescens是应用广泛的植物根际促生菌。目前Azospirillum brasilense与Pseudomonas fluorescens对稻田土壤氮循环和水稻生长发育的影响尚不清楚。本研究通过两年田间试验（2016-2017）解析了Azospirillum brasilense与Pseudomonas fluorescens对水稻根际土壤氮素转化和供氮能力的影响，明确了Azospirillum brasilense与Pseudomonas fluorescens在稻田肥料减施增效中的作用。微生物接种包括4个处理，分别为生理盐水接种（对照，M₀），水稻幼苗接种Azospirillum brasilense（M_b），水稻幼苗接种Pseudomonas fluorescens（M_p），水稻幼苗接种Azospirillum brasilense与Pseudomonas fluorescens的混合物（M_bp）。氮肥施用水平包括4个处理，分别为0 kg N hm^-2（N₀）)，90 kg N hm^-2（N₉₀），180 kg N hm^-2（N₁₈₀），270 kg N hm^-2 （N₂₇₀）。结果表明，与M₀相比，M_bp与M_p处理显著增强了水稻根际土壤氨化作用强度，高氮条件下提升作用更显著。与M₀相比，M_bp与M_b处理显著增强了水稻根际土壤固氮酶活性，低氮条件下提升作用更显著。接种用的Azospirillum brasilense与Pseudomonas fluorescens不参与水稻根际土壤的硝化和反硝化过程。根际促生菌与氮肥的交互作用对土壤呼吸速率与微生物量氮有显著影响。在M_bp处理中，N₉₀、N₁₈₀、N₂₇₀处理的土壤供氮能力与水稻产量无显著差异。水稻幼苗接种Azospirillum brasilense与Pseudomonas fluorescens的混合物，可将该地区氮肥施用量降至90 kg N hm^-2。

Soil productivity (SP) without external fertilization influence is an important indicator for the capacity of a soil to support crop yield. However, there have been difficulties in estimating values of SPs for soils after various long-term field treatments because the treatment without external fertilization is used but is depleted in soil nutrients, leading to erroneous estimation. The objectives of this study were to estimate the change of SP across different cropping seasons using pot experiments, and to evaluate the steady SP value (which is defined by the basal contribution of soil itself to crop yield) after various longterm fertilization treatments in soils at different geographical locations. The pot experiments were conducted in Jinxian of Jiangxi Province with paddy soil, Zhengzhou of Henan Province with fluvo-aquic soil, and Gongzhuling of Jilin Province with black soils, China. Soils were collected after long-term field fertilization treatments of no fertilizer (control; CK-F), chemical fertilizer (NPK-F), and combined chemical fertilizer with manure (NPKM-F). The soils received either no fertilizer (F0) or chemical fertilizer (F1) for 3–6 cropping seasons in pots, which include CK-P (control; no fertilizer from long-term field experiments for pot experiments), NPK-P (chemical fertilizer from long-term field experiments for pot experiments), and NPKM-P (combined chemical and organic fertilizers from long-term field experiments for pot experiments). The yield data were used to calculate SP values. The initial SP values were high, but decreased rapidly until a relatively steady SP was achieved at or after about three cropping seasons for paddy and fluvo-aquic soils. The steady SP values in the third cropping season from CK-P, NPK-P, and NPKM-P treatments were 37.7, 44.1, and 50.0% in the paddy soil, 34.2, 38.1, and 50.0% in the fluvo-aquic soil, with the highest value observed in the NPKM-P treatment for all soils. However, further research is required in the black soils to incorporate more than three cropping seasons. The partial least squares path mode (PLS-PM) showed that total N (nitrogen) and C/N ratio (the ratio of soil organic carbon and total N) had positive effects on the steady SP for all three soils. These findings confirm the significance of the incorporation of manure for attaining high soil productivity. Regulation of the soil C/N ratio was the other main factor for steady SP through fertilization management.

The NAC (NAM, ATAF1/2 and CUC2) transcription factor family plays a key role in plant development and responses to abiotic stress.  GmNAC15 (Glyma15g40510.1), a member of the NAC transcription factor family in soybean, was functionally characterized, especially with regard to its role in salt tolerance.  In the present study, qRT-PCR (quantitative reverse transcription PCR) analysis indicated that GmNAC15 was induced by salt, drought, low temperature stress, and ABA treatment in roots and leaves.  GmNAC15 overexpression in soybean (Glycine max) hairy roots enhanced salt tolerance.  Transgenic hairy roots improved the survival of wild leaves; however, overexpression of GmNAC15 in hairy root couldn’t influnce the expression level of GmNAC15 in leaf.  GmNAC15 regulates the expression levels of genes responsive to salt stress.  Altogether, these results provide experimental evidence of the positive effect of GmNAC15 on salt tolerance in soybean and the potential application of genetic manipulation to enhance the salt tolerance of important crops. 

Middle East respiratory syndrome coronavirus (MERS-CoV), a member of the Coronaviridae family, is the causative pathogen for MERS that is characterized by high fever, pneumonia, acute respiratory distress syndrome (ARDS), as well as extrapulmonary manifestations.  Currently, there are no approved treatment regimens or vaccines for MERS.  Here, we generated recombinant nonvirulent Newcastle disease virus (NDV) LaSota strain expressing MERS-CoV S protein (designated as rLa-MERS-S), and evaluated its immunogenicity in mice and Bactrian camels.  The results revealed that rLa-MERS-S showed similar growth properties to those of LaSota in embryonated chicken eggs, while animal immunization studies showed that rLa-MERS-S induced MERS-CoV neutralizing antibodies in mice and camels.  Our findings suggest that recombinant rLa-MERS-S may be a potential MERS-CoV veterinary vaccine candidate for camels and other animals affected by MERS.

Water shortage has threatened sustainable development of agriculture globally as well as in the North China Plain (NCP).  Irrigation, as the most effective way to increase food production in dry land, may not be readily available in the situation of drought.  One of the alternatives is to supply plants with enough nutrients so that they can be more sustainable to the water stress.  The objective of this study was to explore effects of irrigation and sulphur (S) application on water consumption, dry matter accumulation (DMA), and grain yield of winter wheat in NCP.  Three irrigation regimes including no irrigation (rainfed, I₀) during the whole growth period, once irrigation only at jointing stage (90 mm, I₁), and twice respective irrigation at jointing and anthesis stages (90 mm plus 90 mm, I₂), and two levels of S application including 0 (S₀) and 60 kg ha^–1 (S₆₀) were designed in the field experiment in NCP.  Results showed that increasing irrigation times significantly increased mean grain yield of wheat by 12.5–23.7% and nitrogen partial factor productivity (NPFP) by 21.2–45.0% in two wheat seasons, but markedly decreased crop water use efficiency (YWUE).  Furthermore, S supply 60 kg ha^–1 significantly increased mean grain yield, YWUE, IWUE and NPFP by 5.6, 6.1, 23.2, and 5.6% (across two wheat seasons), respectively.  However, we also found that role of soil moisture prior to S application was one of important greater factors on improving the absorption and utilization of storage water and nutrients of soil.  Thus, water supply is still the most important factor to restrict the growth of wheat in the present case of NCP, supplying 60 kg ha^–1 S with once irrigation 90 mm at the jointing stage is a relatively appropriate recommended combination to improve grain yield and WUE of wheat when saving water resources is be considered in irrigated wheat farmlands of NCP.

The improvement of soil productivity depends on a rational input of water and nutrients, optimal field management, and the increase of basic soil productivity (BSP). In this study, BSP is defined as the productive capacity of a farmland soil with its own physical and chemical properties for a specific crop season under local field management. Based on 19-yr data of the long-term agronomic experiments (1989–2008) on a fluvo-aquic soil in Zhengzhou, Henan Province, China, the decision support system for agrotechnology transfer (DSSAT ver. 4.0) crop growth model was used to simulate yields by BSP of winter wheat (Triticum aestivium L.) and summer maize (Zea mays L.) to examine the relationship between BSP and soil organic carbon (SOC) under long-term fertilization. Five treatments were included: (1) no fertilization (control), (2) nitrogen, phosphorus and potassium fertilizers (NPK), (3) NPK plus manure (NPKM), (4) 1.5 times of NPKM (1.5NPKM), and (5) NPK plus straw (NPKS). After 19 yr of treatments, the SOC stock increased 16.7, 44.2, 69.9, and 25.2% under the NPK, NPKM, 1.5NPKM, and NPKS, respectively, compared to the initial value. Among various nutrient factors affecting contribution percentage of BSP to winter wheat and summer maize, SOC was a major affecting factor for BSP in the fluvo-aquic soil. There were significant positive correlations between SOC stock and yields by BSP of winter wheat and summer maize (P<0.01), and yields by BSP of winter wheat and summer maize increased 154 and 132 kg ha–1 when SOC stock increased 1 t C ha–1. Thus, increased SOC accumulation is a crucial way for increasing BSP in fluvo-aquic soil. The manure or straw combined application with chemical fertilizers significantly enhanced BSP compared to the application of chemical fertilizers alone.

Soil organic carbon (SOC) and soil Olsen-P are key soil fertility indexes but information on their relationships is limited particularly under long-term fertilization. We investigated the relationships between SOC and the percentage of soil Olsen-P to total P (PSOPTP) under six different 15-yr (1990-2004) long-term fertilizations at two cropping systems in northern China. These fertilization treatments were (1) unfertilized control (control); (2) chemical nitrogen (N); (3) N plus chemical P (NP); (4) NP plus chemical potassium (NPK); (5) NPK plus animal manure (NPKM) and (6) high NPKM (hNPKM). Compared with their initial values in 1989 at both sites, during the 11th to 15th fertilization years annual mean SOC contents were significantly increased by 39.4-47.0% and 58.9-93.9% at Gongzhuling, Jilin Province, and Urumqi, Xinjiang, China, under the two NPKM fertilizations, respectively, while no significant changes under the no-P or chemical P fertilization. During the 11th to 15th fertilization years, annual mean PSOPTP was respectively increased by 2.6-4.2 and 5.8-14.1 times over the initial values under the two chemical P fertilizations and the two NPKM fertilizations, but was unchanged in their initial levels under the two no-P fertilizations at both sites. Over the 15-yr long-term fertilization SOC significantly positively correlated with PSOPTP (r2=0.55-0.79, P<0.01). We concluded that the combination of chemical P plus manure is an effective way to promote SOC accumulation and the percentage of soil Olsen-P to total P at the two mono-cropping system sites in northern China.

Increasing basic farmland soil productivity has significance in reducing fertilizer application and maintaining high yield of crops. In this study, we defined that the basic soil productivity (BSP) is the production capacity of a farmland soil with its own physical and chemical properties for a specific crop season under local environment and field management. Based on 22-yr (1990-2011) long-term experimental data on black soil (Typic hapludoll) in Gongzhuling, Jilin Province, Northeast China, the decision support system for an agro-technology transfer (DSSAT)-CERES-Maize model was applied to simulate the yield by BSP of spring maize (Zea mays L.) to examine the effects of long-term fertilization on changes of BSP and explore the mechanisms of BSP increasing. Five treatments were examined: (1) no-fertilization control (control); (2) chemical nitrogen, phosphorus, and potassium (NPK); (3) NPK plus farmyard manure (NPKM); (4) 1.5 time of NPKM (1.5NPKM) and (5) NPK plus straw (NPKS). Results showed that after 22-yr fertilization, the yield by BSP of spring maize significantly increased 78.0, 101.2, and 69.4% under the NPKM, 1.5NPKM and NPKS, respectively, compared to the initial value (in 1992), but not significant under NPK (26.9% increase) and the control (8.9% decrease). The contribution percentage of BSP showed a significant rising trend (P<0.05) under 1.5NPKM. The average contribution percentage of BSP among fertilizations ranged from 74.4 to 84.7%, and ranked as 1.5NPKM>NPKM>NPK≈NPKS, indicating that organic manure combined with chemical fertilizers (1.5NPKM and NPKM) could more effectively increase BSP compared with the inorganic fertilizer application alone (NPK) in the black soil. This study showed that soil organic matter (SOM) was the key factor among various fertility factors that could affect BSP in the black soil, and total N, total P and/or available P also played important role in BSP increasing. Compared with the chemical fertilization, a balanced chemical plus manure or straw fertilization (NPKM or NPKS) not only increased the concentrations of soil nutrient, but also improved the soil physical properties, and structure and diversity of soil microbial population, resulting in an iincrease of BSP. We recommend that a balanced chemical plus manure or straw fertilization (NPKM or NPKS) should be the fertilization practices to enhance spring maize yield and improve BSP in the black soil of Northeast China.

Phosphorus (P) is an essential element for plant growth and yield. Improving phosphorus use efficiency of crops could potentially reduce the application of chemical fertilizer and alleviate environmental damage. Soybean (Glycine max (L.) Merr.) is sensitive to phosphorus (P) in the whole life history. Soybean cultivars with different P efficiencies were used to study P uptake and dry matter accumulation under different P levels. Under low P conditions, the P contents of leaf in high P efficiency cultivars were greater than those in low P efficiency cultivars at the branching stage. The P accumulation in stems of high P efficiency cultivars and in leaves of low P efficiency cultivars increased with increasing P concentration at the branching stage. At the late podding stage, the P accumulation of seeds in high and low P efficiency cultivars were 22.5 and 26.0%, respectively; and at the mature stage were 69.8 and 74.2%, respectively. In average, the P accumulation in whole plants and each organ was improved by 24.4% in high P efficiency cultivars compared to low P efficiency cultivars. The biomass between high and low P efficiency cultivars were the same under extended P condition, while a significant difference was observed at late pod filling stage. At the pod setting stage, the biomass of high P efficiency cultivars were significant greater (17.4%) than those of low P efficiency cultivars under high P condition. Meanwhile, under optimum growth conditions, there was little difference of biomass between the two types of cultivars, however, the P agronomic efficiency and P harvest index were significant higher in high P efficiency cultivars than those in low P efficiency cultivars.

Super high-yielding soybean cultivar Liaodou 14, soybean cultivars from Ohio in the United States, and the common soybean cultivars from Liaoning Province, China, with similar geographic latitudes and identical pod-bearing habits were used as the study materials for a comparison of morphological traits and production characteristics to provide a theoretical basis for the breeding of improved super high-yielding soybean cultivars. Using a randomized block design, different soybean cultivars from the same latitude were compared under conventional and unconventional treatments for their production characteristics, including morphological traits, leaf area index (LAI), net photosynthesis rate, and dry matter accumulation. The specific characteristics of the super high-yielding soybean cultivar Liaodou 14 were analyzed. The results showed that the plant height of Liaodou 14 was significantly lower than that of the common cultivars from Liaoning, whereas the number of its main-stem nodes was higher than that of the cultivars from Ohio or Liaoning. A high pod density was observed in Liaodou 14 under conventional treatments. Under both conventional and unconventional treatments, the branch number of Liaodou 14 was markedly higher than that of the common cultivars from Liaoning, and its branch length and leaf inclination angle were significantly higher than those of common cultivars from Liaoning or Ohio. Only small changes in the leaf inclination angle were observed in Liaodou 14 treated with conventional or unconventional methods. Under each treatment, Liaodou 14 exhibited the lowest amplitude of reduction in SPAD values and net photosynthesis rates from the grain-filling to ripening stages; the cultivars from Ohio and the common cultivars from Liaoning exhibited more significant reductions. Liaodou 14 reached its peak LAI later than the other cultivars but maintained its LAI at a higher level for a longer duration. Under both conventional and unconventional treatments, Liaodou 14 produced a higher yield than the other two cultivars, with significant differences from the Ohio cultivars. In summary, super high-yielding soybean cultivars have several main features: suitable plant height, high pod density, good leaf structure with strong functionality, and slow leaf senescence at the late reproductive stage, which is conducive to the accumulation of dry matter and improved yield.

Selection of quantitative characteristics, division of their expression ranges, and selection of example varieties are key issues on developing DUS Test Guidelines, which are more crucial for quantitative characteristics since their expressions vary in different degrees. Taking the development of DUS Test Guideline of Ranunculus asiaticus L. as an example, this paper applied statistic-based approaches for the analyses of quantitative characteristics. We selected 9 quantitative characteristics from 18 pre-selected characteristics, based on within-variety uniformity, stability between different growing cycles, and correlation among characteristics, by the analyses of coefficient of variation, paired-samples t-test and partial correlation. The expression ranges of the 9 selected quantitative characteristics were divided into different states using descriptive statistics and distribution frequency of varieties. Eight of the 9 selected quantitative characteristics were categorized as standard characteristics as they showed one peak in distribution frequency of 120 varieties in various expressions of the characteristics, whereas, plant height can be categorized as grouping characteristic since it gave two peaks, and can group the varieties into pot and cut varieties. Finally, box-plot was applied to visually select the example varieties, and varieties 7, 12, and 28 were determined as the example varieties for plant height. The methods described in this paper are effective for the selection of quantitative characteristics, division of expression ranges, and selection of example varieties in Ranunculus asiaticus L. for DUS test, and may also be interest for other plant genera.

Conophylline, is a bis (indole) alkaloid consisting of two pentacyclic aspidosperma skeletons, isolated from Tabernaemontana divaricata, which has been found to induce b-cell differentiation in rat pancreatic acinar carcinoma cells and in cultured rat pancreatic tissue. However, the precise role of conophylline in the growth and survival of immortalized pancreatic mesenchymal stem cells (iPMSCs) derived from fetal porcine pancreas were not understood at present. To determine whether this molecule is involved in controlling the proliferation of iPMSCs, we examined the effects of conophylline on iPMSCs. We found that conophylline can robustly stimulate iPMSCs proliferation, even promote their potential differentiation into islet-like clusters analyzed by cell counting, morphology, RT-PCR and real-time PCR, Western blotting, glucose-stimulated insulin release and insulin content analysis. The effects of conophylline were inhibited by LY294002, which is the inhibitor of the PI3K pathway. These results suggest that conophylline plays a key role in the regulation of cell mass proliferation, maintenance of the undifferentiated state of iPMSCs and also promotes iPMSCs differentiated into insulin-producing cells.

Hybrid necrosis is the gradual premature death of leaves or plants in certain F1 hybrids of wheat (Triticum aestivum L.). Comparison of protein expression in necrotic and normal wheat leaves showed that the abundance of 33 proteins was changed significantly, and 24 of these proteins were identified. These proteins were involved in plant growth and development, antioxidation, photosynthesis and carbon assimilation, amino acid and protein biosynthesis, cytological signal transduction, DNA and RNA modification, protein transport, folding and assembly according to their functions. The down-regulation of uroporphyrinogen decarboxylase and the up-regulation of lipoxygenases in necrotic leaves may be related to the oxidative stress in the necrotic cells. The heat shock proteins may play the cytoprotective role. The differential expression of photosynthesis and carbon assimilation related proteins indicated chlorophyll biosynthesis and chloroplast development were inhibited and might finally cause the gradual chlorosis and cell death in necrotic leaves. The results of this study give a comprehensive picture of the post-transcriptional response to necrosis in hybrid wheat leaves and serve as a platform for further characterization of gene function and regulation in wheat hybrid necrosis.