中国饲料粮消费问题探析

为了准确分析中国当前饲料粮供需情况及影响因素,首先通过供给法计算出1984—2013年的狭义饲料粮可供给数据,其次通过需求法计算中国饲料粮消费数据。推算得出饲料粮供需数据虽有差距但都呈增长趋势。中国粮食政策加剧了饲料粮供需失衡状况。因此提出相应政策建议:一是适当增加肉类产品进口并严厉打击走私;二是粮食政策在确保主粮(大米和小麦)基本自给基础上,适度进口饲料粮(主要是玉米),并在海关政策制订上将精饲料原料通盘考虑,制订考虑替代品如大麦、高粱、DDGS等在内的一揽子关税与配额政策。     

自制中药颗粒剂对腹泻仔猪小肠黏膜病理结构及养分消化率的影响

为了研究自制中药复方颗粒剂对腹泻仔猪小肠黏膜组织结构和营养消化率的影响,试验选用人工感染大肠埃希菌引起腹泻的28日龄断奶的杜长大仔猪36头,随机均分为2组,每组3个重复,每个重复6头。抗生素治疗组在饮水中添加盐酸林可霉素2.0 m L/头饮水,2次/d,连续5 d;中药复方颗粒剂治疗组在饮水中添加2.0 g/头饮水,2次/d,连续5 d。分别于用药后14 d时,每组每个重复随机抽取1头屠宰,无菌采集小肠黏膜,通过石蜡切片和HE染色观测小肠黏膜病理组织学变化。其余仔猪继续饲养14 d,采用内源指示剂法进行消化试验。结果显示,小肠黏膜组织结构:中药复方颗粒剂治疗组小肠黏膜除有少量出血外,未发现明显病理变化。抗生素治疗组小肠黏膜脱落,有广泛充血、出血;黏膜上皮细胞变性坏死;嗜酸性粒细胞浸润,有大量以淋巴细胞杯状细胞为主的炎性细胞浸润;微绒毛排列紊乱、脱落;细胞受损严重,线粒体等细胞器结构异常。养分消化率:对于有机物质、磷的消化率,各组之间无显著差异,中药复方颗粒剂治疗组对钙的消化率为57.10%,显著高于抗生素治疗组(56.10%),并与健康仔猪组(57.40%)差异不显著。中药复方颗粒剂治疗组对粗蛋白质的消化率为79.30%,显著高于抗生素治疗组(78.50%),并与健康仔猪组(79.20%)差异不显著。中药复方颗粒剂治疗组对粗纤维的消化率为48.30%,极显著高于抗生素治疗组(46.10%),并与健康仔猪组(48.20%)差异不显著。中药复方颗粒剂治疗组对粗脂肪的消化率为63.40%,极显著高于抗生素治疗组(62.10%),并与健康仔猪组(63.60%)差异不显著。结论:抗生素治疗仔猪腹泻造成小肠黏膜明显的病理变化和功能障碍,而中药治疗有利于仔猪小肠黏膜组织结构的修复,并能显著提高小肠的养分消化率。为防治仔猪腹泻、提高仔猪的生长性能提供依据。     

Occupancy pattern of a long-horned beetle in a variegated forest landscape: linkages between tree quality and forest cover across spatial scales

Context

Interactions between landscape-scale processes and fine-grained habitat heterogeneity are usually invoked to explain species occupancy in fragmented landscapes. In variegated landscapes, however, organisms face continuous variation in micro-habitat features, which makes necessary to consider ecologically meaningful estimates of habitat quality at different spatial scales.

Objectives

We evaluated the spatial scales at which forest cover and tree quality make the greatest contribution to the occupancy of the long-horned beetle Microplophorus magellanicus (Coleoptera: Cerambycidae) in a variegated forest landscape.

Methods

We used averaged data of tree quality (as derived from remote sensing estimates of the decay stage of single trees) and spatially independent pheromone-baited traps to model the occurrence probability as a function of multiple cross-scale combinations between forest cover and tree quality (with scales ranging between 50 and 400 m).

Results

Model support and performance increased monotonically with the increasing scale at which tree quality was measured. Forest cover was not significant, and did not exhibit scale-specific effects on the occurrence probability of M. magellanicus. The interactive effect between tree quality and forest cover was stronger than the independent (additive) effects of tree quality and particularly forest cover. Significant interactions included tree quality measured at spatial scales ≥200 m, but cross-scale interactions occurred only in four of the seven best-supported models.

Conclusions

M. magellanicus respond to the high-quality trees available in the landscape rather than to the amount of forest per se. Conservation of viable metapopulations of M. magellanicus should consider the quality of trees at spatial scales >200 m.

     

QTL mapping and analysis of epistatic interactions for grain yield and yield-related traits in <Emphasis Type="Italic">Triticum turgidum</Emphasis> L. var. <Emphasis Type="Italic">durum</Emphasis>

A quantitative trait loci (QTL) analysis of grain yield and yield-related traits was performed on 93 durum wheat recombinant inbred lines derived from the cross UC1113 × Kofa. The mapping population and parental lines were analyzed considering 19 traits assessed in different Argentine environments, namely grain yield, heading date, flowering time, plant height, biomass per plant, and spikelet number per ear, among others. A total of 224 QTL with logarithm of odds ratio (LOD) ≥ 3 and 47 additional QTL with LOD > 2.0 were detected. These QTL were clustered in 35 regions with overlapping QTL, and 12 genomic regions were associated with only one phenotypic trait. The regions with the highest number of multi-trait and stable QTL were 3BS.1, 3BS.2, 2BS.1, 1BL.1, 3AL.1, 1AS, and 4AL.3. The effects of epistatic QTL and QTL × environment interactions were also analyzed. QTL putatively located at major gene loci (Rht, Vrn, Eps, and Ppd) as well as additional major/minor QTL involved in the complex genetic basis of yield-related traits expressed in Argentine environments were identified. Interestingly, the 3AL.1 region was found to increase yield without altering grain quality or crop phenology.     

1976—2017年青海湖东北部地区极端降水事件变化特征分析

为进一步了解高寒牧区气候变化,依据1976—2017年青海湖东北部海晏站逐日降水资料,采用百分位法确定冬、夏半年极端降雨（雪）阈值并统计极端降水事件,运用线性趋势、R/S和小波分析法分析极端降水事件变化特征、未来演变趋势及周期。结果表明：青海湖东北部地区冬、夏半年极端降水日数和极端降水量呈不显著增加趋势;冬半年极端降水强度和日最大降水量不显著增加,而夏半年不显著减小;极端降水对年降水的贡献率均以不同的速率增加,其中夏半年的极端降水对年降水的影响较大;冬半年降水日数不显著减小,而降水量显著增加,表明冬半年发生短时强降水的几率增大,夏半年的降水日数和降水量增加不明显;未来,冬半年极端降水日数增加趋势将发生转变,极端降水量与之前的变化趋势无关将继续呈现震荡性,其他各要素将持续前期的变化趋势;冬（夏）半年极端降水日数和降水量分别存在明显的周期变化特征。高寒牧区的极端降水研究对于预防短时强降水带来的雪灾、洪涝事件的发生意义重大。     

施氮时期对葡萄叶片光合生理及内源激素水平的影响

以10 a生酿酒葡萄‘蛇龙珠’为试验材料，运用水肥一体化滴灌的方式分别在萌芽期（S1）、新梢旺长期（S2）、开花期（S3）、果实第一次膨大期（S4）和副梢生长旺期（S5）一次性施入300 kg·hm^-2尿素，对照为整个生育期均不施氮肥（CK），分别于花后50 d（DAF50）、花后85 d（DAF85）和花后120 d（DAF120）进行光合特性指标的测定，并采样分析氮肥施用时期对葡萄叶片光合生理及内源激素水平的影响。结果表明：各生育期施氮均能增加叶片净光合速率（Pn）及PSⅡ最大光化学效率（Fv/Fm），在花前施氮肥叶片Pn和Fv/Fm增加最为显著，最高分别达到18.22 μmol·m^-2·s^-1和0.854。S1、S2和S3处理显著增大了不同生育期叶片气孔导度（Gs）和蒸腾速率（Tr），且S2处理在DAF85时最显著，Gs和Tr分别比CK高18.5%和10.8%；S3、S4和S5处理显著降低了叶片的胞间CO₂浓度（Ci）和非光化学淬灭系数（NPQ），S1处理叶片Ci与CK之间无显著差异。果实第一次膨大期之前施入氮肥能够显著增大各生育期叶片的PSⅡ电子传递量子效率（ФPSⅡ）和光化学淬灭系数（qP），最高分别达到0.889和0.959。可见，不同时期施氮肥，通过改变光合荧光相关参数影响叶片光能的吸收、传递、耗散和分配，从而改善叶片光能利用效率。氮肥的施用时期影响各生育期叶片内源激素的含量，施氮肥均显著提高了DAF85后叶片玉米素（ZT）含量，与CK相比至少提高21.9%；花后施入氮肥叶片中IAA含量在果实采收时保持在34.9 μg·g^-1以上，S4和S2处理GA₃含量最高，分别为7.11 μg·g^-1和6.49 μg·g^-1。因此，氮肥施用时期影响葡萄各生育期不同内源激素的积累。     

非会计专业《会计学》课程教学方法刍议

目前,许多高校非会计专业都将《会计学》课程作为一门专业必修的基础课程。结合多年的非会计专业会计教学经验,笔者认为根据专业特点,采用灵活多样的教学方法是实现非会计专业《会计学》课程教学目标,提高《会计学》教学效果的重要手段。     

Successive grafting confers juvenility traits to adult Spanish red cedar (Cedrela odorata Linnaeus): a tool for the rescue of selected materials

New Forests - Spanish red cedar, Cedrela odorata L. (Meliaceae), is a valuable timber tree in tropical American forests. Existing demand for elite individuals endangers the conservation of...     

低温贮藏对猕猴桃果实成熟软化相关基因表达影响

为探究低温对果实采后成熟软化与淀粉降解的影响,以红阳猕猴桃果实为试验材料,研究在低温贮藏期间,猕猴桃果实硬度,可溶性固形物、乙烯、淀粉含量以及淀粉酶相关基因的变化。结果表明,低温贮藏能显著抑制猕猴桃果实采后成熟软化,延缓果实淀粉的降解和可溶性固形物含量的增加,维持贮藏期间果实较高的硬度。低温贮藏抑制乙烯合成关键基因AcACO1和AcACS1的表达,抑制乙烯合成。同时,低温贮藏显著抑制淀粉降解相关基因AcAMY1、AcBAM1/3、AcISA3、AcLDA1和AcDPE1的表达。在低温贮藏后期,淀粉酶相关基因AcAMY1、AcBAM1/3、AcLDA1和AcDPE1的表达与乙烯释放速率有关。综上,低温贮藏延缓猕猴桃采后成熟软化进程与淀粉降解密切相关,可能主要通过抑制乙烯合成,从而影响贮藏后期淀粉降解速率,最终延缓果实软化进程。本研究结果为猕猴桃采后低温贮藏提供了理论依据。