浅圆仓玉米破碎率调查报告

本文通过对浅圆仓储存玉米的破碎率进行调查，分析了输送流程中各种输送设备对玉米破碎率的影响程度；通过对入储浅圆仓后的玉米破碎率高低的分布作较详尽的调查，指出玉米破碎导致脂肪酸值快速升高，影响了玉米储存安全。文章提出了影响玉米破碎率的因素和减少破碎率的建议。     

How to maintain improved cultivars

Improved cultivars loose their identity and healthiness unless maintained properly. Contaminating and degrading forces, such as outcrossing, volunteer plants, mixing, natural selection, mutation and seed-borne diseases, are at the root of this. Maintenance selection can prevent this deterioration. How it is carried out depends on the reproduction system of the crop. Crops are therefore classified into four categories; typical cross-pollinating crops, self-pollinating crops with a substantial amount of outcrossing, typical self-pollinating crops with little outcrossing, and the vegetatively reproduced crops. Generally some of the “breeder seed” is used to plant a small plot with spaced plants. A fair number of healthy plants of the cultivar type is selected and the seed is harvested per plant. The progenies of the selected plants are grown in small plots. Non-uniform or deviating plots and plots with a seed-borne disease are removed. The seed of the progenies that are healthy, uniform and similar (and so of the cultivar type) are harvested per progeny to be tested next season on larger plots. The same selection is applied and only the seed of the progenies that are healthy, uniform and similar are harvested together to produce the “breeder seed”. The details of this maintenance selection vary with the reproduction system, the multiplication rate of the crop and the possibilities available to the breeder. Seven crops, potato, common bean, barley, wheat, faba bean, quinoa and maize are discussed here as they represent the different reproduction systems and multiplication rates, while being important Andean food crops.     

华西箭竹(Fargesia nitida)种子特征及其萌发特性

华西箭竹(Fargesia nitida)是大熊猫天然采食的主要竹种之一,由于开花习性独特,对其种子的研究报道还很少见。对华西箭竹种子的基本特征及不同温度下的萌发特性进行了研究。结果表明:华西箭竹种子长为(5.01±0.43)mm、宽(1.99±0.18)mm、厚(1.72±0.13)mm、千粒重(11.51±0.07)g;风干种子的化学组成:水分含量为(10.22±0.36)%、淀粉(74.52±0.57)%、粗蛋白(7.54±0.32)%、粗脂肪(3.71±0.17)%、可溶性糖(2.94±0.21)%、其他成分仅占(1.04±0.01)%。其种子萌发的适宜温度为20~25℃;低于20℃或高于25℃,种子的萌发率都会下降。     

影响籼粳稻杂交F1花药培养效果的因素分析

以津稻291/IRBB60籼粳杂交F1、反交F1及其亲本的花药为外植体,对诱导和分化培养基、激素配比及有机附加物和高温预培养时间等影响花药培养效果的因素进行研究。结果表明,在SK3基本培养基中添加2 mg/L 2,4-D,1 mg/L NAA和1 mg/L KT比只添加2 mg/L 2,4-D的愈伤诱导率高0.67～2.78个百分点;在诱导培养基中添加水解酪蛋白能明显提高正交F1的愈伤诱导率;MS 1 mg/L NAA 2 mg/L 6-BA 0.5 mg/L KT分化培养基得到了较高的绿苗分化率;正交F1的愈伤诱导率、绿苗分化率和花培力显著高于反交F1;30℃高温预培养36 h,正交F1花培力达到最高值。     

不同施肥条件对鱼腥草碳氮代谢生理指标的影响

【研究目的】结合前期对产量、品质的研究，探讨不同施肥条件下鱼腥草叶片主要碳氮代谢指标的变化及其与产量形成的关系。【方法】采用单因子随机区组设计进行施肥实验，测定鱼腥草叶片光合速率、硝酸还原酶活性、叶绿素和粗蛋白的含量。【结果】各施肥处理中以较低施肥水平人粪尿处理的鱼腥草叶片含叶绿素总量最高，达2.552 mg/gFW，以中等施肥水平鸭粪的净光合速率最高，为8.306μmol/(m2·s)。施用不同肥料的鱼腥草叶片硝酸还原酶活性大小为：鸭粪>猪粪>常规施肥>化肥>人粪尿，各处理以中等施肥水平的猪粪处理的硝酸还原酶最高，达46.2μg NO2-/(h·g)FW；粗蛋白以施用较高水平化肥的最高（13.31%）。【结论】施用有机肥能显著提高鱼腥草叶片的碳代谢，这有利于其产量的形成；但施用人粪尿不利于提高鱼腥草叶片硝酸还原酶活性和蛋白质的形成与积累。     

小麦航天诱变育种效果研究

利用返回式卫星搭载两个小麦品种（系）种子进行空间诱变处理，对SP2代农艺性状变异效果进行了分析。结果表明，两个品种（系）的农艺性状均发生了变异，但株系内变异多数为不显著。两个品种（系）的诱变率和性状的变异方向存在差异，豫农201的诱变率高于大粒1号；大粒1号变异株系的性状指标多数为增加，豫农201变异株系的性状指标多数为减少。性状间的诱变率具有差异，株高和粒重的诱变率明显高于其它性状     

对废活性炭回收利用的探讨

将废活性炭用水洗净后,在110℃烘箱中干燥4h,然后将其按不同温度和时间在马福炉中加热和冷却,采用碘量法测定活性炭对碘的吸附率。分析活性炭的脱色能力,找出实验最佳方案,最后利用糖浆脱色实验与新的活性炭比较。实验结果,经过再生的活性炭脱色能力达到原来的73.53%(脱色率比较),脱色糖浆的使用性能及使用寿命与新的活性炭相当。     

Nitrogen mineralization in sandy loam soils under an intensive double-cropping forage system with dairy-cattle slurry applications

Nitrogen (N) mineralization and soil mineral N contents were measured at 2-week intervals over a 2-year period (June 1994–May 1996) on two different sites in the North West region of Portugal. The experiment was established in fields, which had for many years been under a double-cropping forage system with maize from May to September and a winter crop (mixture of cereals and Italian ryegrass) during the rest of the year. In addition to N fertilizers, dairy-cattle slurry was applied regularly at the sowing of each crop. On this intensive forage system, quantification of N released from slurry, crop residues and soil organic matter becomes important when better N use efficiency and reduced environmental impact from agricultural practices are required. Net N mineralization rates of the 0–10 cm soil layer fluctuated considerably between consecutive incubation periods and ranged from −0.88 to 1.87 mg N kg⁻¹ day⁻¹ with annual average rates of between 0.41 and 0.65 mg N kg⁻¹ day⁻¹. The total N mineralized in the 10 cm depth soil layer reached values between 122 and 224 kg N ha⁻¹ year⁻¹, showing that mineralization was a very important N source for the crops. The amounts of N released during the cold season (November–February) were equivalent to 27–48% of the yearly total. Regression analysis indicated that seasonal variation in N mineralization was only poorly explained by soil moisture and temperature. The changing balance during the year between soil moisture and temperature will contribute to the relatively constant N mineralization rates. Soil mineral N contents during the maize crop were high and exceeded the nutrient requirements for the optimum yield of this crop. Under the climatic conditions of the region and due to the poor development of the winter crop plants at the time, the mineral N left in the soil after the maize crop and released by mineralization during the cold season is particularly vulnerable to nitrate leaching losses.     

2种熟型玉米籽粒灌浆特性及其与产量关系的比较研究

为了明确不同熟型玉米籽粒灌浆特性及其对产量的影响,比较研究了中晚熟品种农大108和中早熟品种石玉7号籽粒灌浆动态与产量表现,并对籽粒灌浆特性与籽粒水分的关系进行了分析。结果表明,石玉7号与农大108产量差异显著,百粒重是两品种产量差异的主要原因;石玉7号具有籽粒发育速度快、体积大等特点,前中期（0-45d）灌浆速率始终快于农大108,生育后期（45 d以后）急剧下降。农大108后期灌浆速率则下降缓慢。籽粒发育速度快,灌浆盛期灌浆速度快、强度大是石玉7号百粒重高的主要原因;籽粒水分状况与籽粒灌浆速率关系密切。回归分析表明,籽粒含水百分率在59.47%左右时,石玉7号灌浆速率达到最大值,为9.28 mg/（粒.d）;农大108则在57.92%左右时,灌浆速率达到最大值,为8.23 mg/（粒.d）。当籽粒含水百分率下降到某一临界值时,籽粒灌浆停止。两品种收获时,籽粒含水百分率尚远在籽粒灌浆终止临界值以上。     

Ca^2＋,BR对玉米呼吸器官耐冷性的影响

研究了外源Ｃａ２＋、ＢＲ对低温下玉米胚芽呼吸速率、膜透性以及对线粒体呼吸控制比、ＳＯＤ活性和ＭＤＡ含量的影响。结果表明，Ｃａ２＋、ＢＲ处理，相应提高了种苗胚芽的呼吸速率，降低膜透性。低温下经Ｃａ２＋、ＢＲ处理的玉米种苗，其线粒体有较高的呼吸控制比。Ｃａ２＋处理的线粒体中ＳＯＤ活性比对照高；ＭＤＡ含量比对照低。Ｃａ２＋和ＢＲ可能是在低温下通过维持膜系统的正常结构和功能来提高玉米种苗的耐冷性的