粮食产量预测理论、方法与应用Ⅰ.科技进步增产理论、模型及其应用

粮食增产趋势及增产原因是国家制定宏观农业政策和措施的依据。科技进步增产理论是指：气候是波动的,科技是持续进步的,它是粮食多年持续增产的主要驱动力;科技进步增产预测模型是多年平均单产移动的回归方程。全国和东北三省粮食增产潜力案例分析结果表明：科技进步单产加速时间最早的是辽宁省,最晚的是黑龙江省;与全国相比,吉林省和辽宁省科技进步贡献率高于全国平均水平,黑龙江省低于全国平均水平,吉林省最高。本文初步得出以下结论：科技进步增产理论科学、模型实用、预测结果准确。     

基于网络组织视角的粮食产业化模式与优化路径

在全球粮食安全状况严峻以及中国人多地少的形势下,探讨粮食的产业化发展具有重要意义。从网络组织视角出发,梳理了中国粮食产业化模式并提出优化路径。研究表明：粮食产业化发展是一个网络化的成长过程。基于网络主体控制与参与网络的能力、融资形式以及立足或服务的空间尺度,可以将粮食产业化模式划分为“国家调控跨国公司组织模式”“地方主导龙头企业带动模式”“政府主导社会多元主体参与模式”和“市场主导私营企业推动模式”这四类主要模式,分别对应介于市场组织与等级制组织之间的全球—区域—本地网络组织,并以跨国公司、本地龙头企业、产业化联合体、产业园区、产业集群等产业化组织形式呈现。进一步建议从提升网络主体开始,通过优化网络结构、强化网络载体、完善网络治理来指导粮食产业化的高质量发展。     

Scotch Pine Pollen under Conditions of Environmental Stress

Environmental conditions causing stress have a significant effect on the generative organs of Scotch pine. The parameters characterizing pine pollen are subject to significant interannual variations and are closely connected with weather and climatic conditions in the period of pollen formation. Airborne pollutants affect the quality of pine pollen, which is especially apparent in the years favorable for the formation of microspores. The ability of Scotch pine pollen to germinate and form pollen tubes in the regions with different technogenic loads proved to be significantly lower than in tree stands of the background areas.     

基于随机森林的耕地利用效率测度模型构建及其应用

构建合适的量化分析模型是科学把握耕地利用状况及利用效率的基础性工作,可为制定合理有效的耕地资源管控政策,实现耕地利用与生态环境的协调发展提供决策依据。为了更准确地反映耕地利用系统的复杂性、动态性及差异性等特征,鉴于随机森林的基本思想,运用随机抽样Bootstrap法在合理构建分类树的基础上,构造了耕地利用效率测度的RF模型,进而以中国粮食主产区172个城市为例训练该模型并将其运用至2003-2015年的耕地利用效率测度中,同时将BP神经网络和熵权法作为对比验证其一致性、代表性和优越性。结果表明：（1）耕地利用效率测度的RF模型不受量纲限制,运行所需参数少,运算过程简化,能够较为精确地模拟各评价指标间的复杂联系,科学量化各评价指标对耕地利用效率的贡献。（2）对同一空间单元的效率值而言,RF>BPNN>EW,RF与BPNN所得效率值的总体分布格局相似,且均与EW的测度结果存在较大差异。（3）从评价结果与现实的匹配度和精度表征参数来看,RF的测度结果与自然和社会经济发展等客观事实更相符,具有较高的适用性与可靠性。同时,与其余两种常用模型相比,RF能够降低计算复杂度,提高训练效率,其测度结果的相关系数R为0.8685,M_RPD为2.3533,且具有最小M_MSE0.0174和M_MAE0.0211,更适用于复杂非线性特征的耕地利用效率研究。     

Kinetic and thermodynamic studies on partitioning of polychlorinated biphenyls (PCBs) between aqueous solution and modeled individual soil particle grain sizes

The significance of soil mineral properties and secondary environmental conditions such as pH, temperature, ionic strength and time in the partitioning of eight selected polychlorinated biphenyl(PCB) congeners between aqueous solution and soil particles with different grain sizes was studied. The mineral properties of a model soil sample were determined, and Brunauer–Emmett–Teller(BET) adsorption–desorption isotherms were employed to observe the surface characteristics of the individual modeled soil particles.Batch adsorption experiments were conducted to determine the sorption of PCBs onto soil particles of different sizes. The results revealed that the sorption of PCB congeners onto the soil was dependent on the amount of soil organic matter, surface area, and pore size distribution of the various individual soil particles. Low pH favored the sorption of PCBs,with maximum sorption occurring between pH 6.5 and 7.5 with an equilibration period of 8 hr.Changes in the ionic strength were found to be less significant. Low temperature favored the sorption of PCBs onto the soil compared to high temperatures. Thermodynamic studies showed that the partition coefficient(K_d) decreased with increasing temperature, and negative and low values of ΔH° indicated an exothermic physisorption process. The data generated is critical and will help in further understanding remediation and cleanup strategies for polluted water.     

长江流域粮食资源及生产发展方向

论述长江流域发展粮食生产的重要性，分析粮食资源分布，生产状况，生产结构和地域差异，指出粮食合理布局的方向，提出以粮食集中产区为重点，建设长江流域粮食生产专业化地并以建设商品粮基地为建带突破口。     

Preliminary Studies on Converting Agricultural Waste into Biodegradable Plastics—Part IV: Polysaccharide Containing Natural Materials

Corn distillers’ dry grain, corncob powder, hardwood powder, and sugar beet pulp were separately anionized by oxidation with sodium hypochlorite in aqueous solution. Solid reaction products instantly precipitated upon admixing each of the above-oxidized materials with soy protein isolate. Infrared spectra and differential scanning calorimetry supported the hypothesis that soy protein isolate complexed with all of the above-oxidized polysaccharides. Reaction products with either oxidized corn distillers’ dry grain or oxidized sugar beet pulp provided hard, brittle pellets with tensile strengths as high as 9.5 MPa, suggesting that these materials could be viable as biodegradable plastics.     

大气臭氧浓度升高对丛枝菌根(AM)及其功能的影响

通过模拟大气O₃浓度(0.02μL·L^-1、0.1μL·L^-1和0.2μL·L^-1)升高,观察其对丛枝菌根(AM)及功能的影响.结果表明,大气O₃浓度升高对菌根侵染率影响较小,但对孢子和外生菌丝影响显著,高浓度O₃时的孢子数比自然O₃浓度时增加1倍,低、高浓度O₃分别使AM外生菌丝量比自然浓度时下降48.7%和85.6%.随着O相似文献   

转Bt-cry1Ac棉花花粉对意大利蜜蜂生长发育的影响

研究了取食转Bt-cry1Ac棉花花粉对意大利蜜蜂的影响,主要包括意大利蜜蜂的生长发育、体内酶活性的变化.结果发现,取食转Bt-cry1Ac基因棉花花粉的意大利蜜蜂与取食非转基因亲本棉花花粉的蜜蜂(CK)相比,4、5、6日龄幼虫体重差异不显著,幼虫及蛹的历期也没有明显差异.取食转Bt-cry1Ac基因棉花花粉的意大利蜜蜂6日龄幼虫体内的谷胱甘肽-S-转移酶、总蛋白酶活力与CK相比,没有显著差异.取食转Bt-cry1Ac基因棉花花粉的意大利蜜蜂幼虫体内的α-乙酸萘酯酶、乙酰胆碱酯酶活力极显著高于CK,强碱性、弱碱性类胰蛋白酶活力极显著低于CK,类胰凝乳蛋白酶活力显著低于CK.另外,采用酶联免疫(ELISA)方法在取食转Bt-cry1Ac基因棉花花粉的蜜蜂6日龄幼虫体内能够检测到Bt杀虫蛋白.表4参12     

丁布的分离、纯化和结构鉴定及其对麦长管蚜

从玉米苗中分离、纯化得到丁布，利用纸层析，紫外分光光度扫描和核磁共振^1H NMR等技术对其作结构鉴定。结果与文献报道基本一致，且纯度在96.7%以上，以纯化的丁布为标样，用HPLC方法分析了不同抗性级别的小麦品种中丁布的含量。结果表明：品种之间丁布的含量差异显著，丁布的浓度与小麦的抗蚜级别呈显著负相关，与麦长管蚜的内禀增长率rm亦呈显著负相关，借助麦长管蚜全纯人工饲料研究表明，丁布对麦长管蚜有明显的拒食性作用。图3表2参13。