Effects of nitrogen rate and ratio of base fertilizer and topdressing on uptake, translocation of nitrogen and yield in wheat

Application of nitrogen (N) fertilizer is one of the most important measures to increase grain yield and protein content in winter wheat (Triticum aestivum L.) production. However, misuse of N Tertilizer will not only affect gram yield and quality, but also cause the decline of economic benefits and related negative environmental effects. It is essential to study reasonable N application regimes for profitable yields, efficient N utilization and reduction in possible environmental pollution. The objective of this study was to determine the N uptake and translocation in wheat plants by using ¹⁵N isotope tracers in PVC cylinders (2.05 m long, ϕ 0.2 m, without bottom) in seven treatments: without N fertilizer application (N0); N application rate of 168 kg/hm² (0.527 g/pot), with ratios of base fertilizer to topdressing of 1:1 (N1), 1:2 (N2) and 0:1 (N3); N application rate of 240 kg/hm² (0.753 g/pot), with ratios of base fertilizer to topdressing of 1:1 (N4), 1:2 (N5) and 0:1 (N6). The ¹⁵N tracer experiment showed that the main basal N absorbed by plant from sowing to jointing stage accounted for 78.04%–89.67%; fertilizer N use efficiency (FNUE, N fertilizer accumulation in plant/N supplied) of topdressing was significantly higher than that of basal N; reducing basal N amount and increasing topdressing N amount could appropriately promote the plant’s absorption of more N fertilizer and enhance FNUE, of which treatment N2 had the highest values. Under the high-yield condition, when N fertilizer rate was increased from 168 to 240 kg/hm², there were no significant differences in the amount of N accumulation in plants and in grains between treatments with the same ratio of base fertilizer to topdressing; by reducing basal N amount and increasing topdressing N amount accordingly, the translocation efficiency (TE, accumulation amount from vegetative organs to gram/N accumulation in vegetative organs during anthesis) increased, and the amount of N assimilation to grains after anthesis and its contribution proportion (the amount of N assimilation to grains after anthesis/N accumulation in grain) also increased. In other words, grain N accumulation amount increased with increasing amount of topdressing N at the same N fertilizer rate. There were no significant differences among treatments N2, N3, N5 and N6 in grain N accumulation. Appropriate N fertilizer rate with a reduction in basal N amount and an increase in topdressing N amount such as in N2, N5 and N6 increased grain yield and protein content. In conclusion, under conditions used in this experiment, as far as grain yield, protein content and FNUE are concerned, the recommended appropriate N fertilizer application regime is treatment N2, with a N fertilizer rate of 168 kg/hm² and a ratio of base fertilizer to topdressing of 1:2. Translated from Journal of Acta Agronomica Sinica, 2006, 32(12): 1860–1866 [译自: 作物学报]     

东方百合四倍体及2 n雌配子杂种后代RAPD分析

对组培条件下秋水仙素诱变的东方百合四倍体及2 n雌配子杂种后代进行了RAPD分析.结果表明：东方百合四倍体诱导过程中,少数植株除了染色体数目加倍以外,还存在DNA序列的改变;2 n雌配子杂种后代RAPD分析表现出丰富的遗传多样性,少数植株RAPD分析差异巨大,特别是T8无性后代存在较大的性状差异,个别植株经RAPD分析与其他单株存在较大的差异.     

中国北部高原地区谷子(粟)品种高产稳产性的评价

 利用回归系数法、稳定性参数法和高稳系数法 ,对我国北部高原地区新育成的 18个新品种 (系 )的高产稳产性进行了研究。结果表明 ,参试品种多数产量较高 ,占 5 5 .5 % ,但其中产量稳定性较差的占多数 ,高产稳产的品种较少 ,仅有铁 93- 115、95汾选 3和承谷 8号 ,占 16 .7% ,其余的均为低产稳产和低而不稳的类型 ,各占 2 2 .2 %。这可能与品种性状的适应性有关     

某些香辛料精油抑制N—二甲基亚硝胺体外合成的研究

模拟在胃液条件下，８种香辛料精油对Ｎ－二甲基亚硝胺（ＮＤＭＡ）体外合成的阻断作用。结果表明，除丁香外，其余７种香辛油都有不同程度阻断ＮＤ－ＭＡ合成的作用。其中，韭菜籽、芫荽籽、姜和小茴香的阻断效果明显优于等剂量的抗坏血酸。７种香辛油均有消除亚硝酸钠的作用，但其消除作用小于等剂量的ＶｉｔＣ液。这表明香辛料精油中的有效成分能消除反应液中的亚硝酸盐。     

产量9000kg/hm2麦田速效养分肥力指标研究

为配合河南省小麦高产县9000 kg/hm~2产量的栽培攻关,2002年在种麦前根据当年产量情况,对河南省9000 kg/hm~2产量麦田进行了取样化验,旨在探讨9000 kg/hm~2产量麦田适宜的养分肥力指标,为今后麦田合理施肥提供依据。     

几种化学药剂对早熟桃果实品质的影响

以５年生毛桃砧布目早生桃为试材，采用叶面喷施方法，研究了植物生长调节剂和营养元素对提高早熟桃果实品质的效应。结果表明，丰果素１号、甜之宝、磷酸二氢钾、比久（Ｂ９）、植物生长剂、氯化钾促进果实着色的效果明显；除了比久有降低单果重的趋势外，其余各处理都能增加单果重７％～１７％，与对照呈显著性差异；丰果素１号、增糖灵、磷酸二氢钾提高可溶性固形物（１．３％～１．５％）的效果最佳；丰果素１号、增糖灵、甜之宝、磷酸二氢钾、达苜生、２１１－３２农用稀土复合剂增糖（１．３％～１．５％）效果明显，它们（除磷酸二氢钾外）的减酸（０．１１％～０．１２％）效果也显著。尤其是丰果素１号对提高果实着色、增加单果重、提高可溶性固形物和总糖，降低果实中总酸含量均有显著作用，可在生产上应用。     

The Gelation of CO(2): A Sustainable Route to the Creation of Microcellular Materials

Compounds with strong thermodynamic affinity for carbon dioxide (CO(2)) have been designed and synthesized that dissolve in CO(2), then associate to form gels. Upon removal of the CO(2), these gels produced free-standing foams with cells with an average diameter smaller than 1 micrometer and a bulk density reduction of 97 percent relative to the parent material.     

不同苜蓿品种比较试验

在中等肥力土壤条件和每公顷播种量7.5kg的情况下，分析从美国引进的4个不同苜蓿品种和我国的中苜1号在产草量，营养成分，氨基酸含量以及经济效益上的差异性。结果表明：引进的4个苜蓿品种产草量和经济效益均高于国内品种55％－80％，其中以MHA2品种的产草量，经济效益最好，具有推广意义。     

隐性乳房炎乳汁中体细胞和病原菌及酶间的相关性

对奶牛隐性乳房炎乳汁中体细胞、乳酸脱氢酶（ＬＤＨ）、碱性磷酸酶（ＡＬＰ）、酸性磷酸酶（ＡＣＰ）、谷氨酸草酰乙酸转氨酶（ＧＯＴ）、谷氨酸丙酮酸转氨酶（ＧＦＴ）和血清白蛋白（ＳＡ）及病原微生物的相关性进行了研究。结果发现ＬＤＨ，ＡＣＰ，ＧＯＴ，ＧＰＴ的活性和ｓＡ的含量变化与白细胞数之间存在极显著的相关关系（Ｐ＜０．０１），尤以ＬＤＨ的相关性最强（ｒ＝０．８５８）；ＡＬＰ与体细胞数之间无相关关系（Ｐ＞０．０５）．不同的乳房炎病原微生物感染乳腺呈现不同的酶象变化，与阴性感染的乳腺相比，各酶的活性均出现增加，尤以金黄色葡萄球菌感染的乳腺有关酶的增加幅度最为显著（Ｐ＜０．０１）。