多功能农业是都市农业的方向

<正>发展多功能农业是现代农业发展与进步的一个必然趋势。它的发展不但顺应宏观经济发展的现实,而且捕捉到了大中城市农业发展的切入点,同时也对今后都市农业的发展提出新的要求和挑战。农业的多功能性和多功能性的农业20世纪80年代末90年代初,农业的多功能性最先出现在日本的"稻米文化"中。     

Acid catalysis in basic solution: a supramolecular host promotes orthoformate hydrolysis

Although many enzymes can promote chemical reactions by tuning substrate properties purely through the electrostatic environment of a docking cavity, this strategy has proven challenging to mimic in synthetic host-guest systems. Here, we report a highly charged, water-soluble, metal-ligand assembly with a hydrophobic interior cavity that thermodynamically stabilizes protonated substrates and consequently catalyzes the normally acidic hydrolysis of orthoformates in basic solution, with rate accelerations of up to 890-fold. The catalysis reaction obeys Michaelis-Menten kinetics and exhibits competitive inhibition, and the substrate scope displays size selectivity, consistent with the constrained binding environment of the molecular host.     

棉花良种加工质量的全程控制

棉花良种加工质量的全程控制江苏省东台市种子公司黄慧明，任颐东台市原种轧花剥绒厂开卫清，崔益富随着棉种深加工生产线的不断建成，棉花良种的标准化、商品化水平随之提高。如何保证棉花良种的加工质量，以提高播种品质？对于加工质量控制的内涵，不应只围于原有的机械...     

宽幅匀播对陇中引黄灌区春小麦主要性状及产量的影响

在景电灌区和引大灌区分别以春小麦品种宁春39号和永良15号为指示作物,比较了宽幅匀播与常规条播2种方式下不同播种方式的春小麦主要性状及产量。结果表明,与常规条播处理相比,宽幅匀播均能够明显促进小麦分蘖,增加穗长,提高单位面积结穗数和千粒重,增产率在10%以上,可在甘肃中部引黄灌区示范推广。     

All-Carbon Molecules: Evidence for the Generation of Cyclo[18]carbon from a Stable Organic Precursor

The unambiguous structural characterization of a single-sized all-carbon molecule requires its chemical synthesis. For cyclo[18]carbon, ab initio calculations predict a relatively stable, cyclic D9h ground state geometry with alternating C-C (1.36 angstroms) and C identical withC (1.20 angstroms) bonds. The synthesis and x-ray crystal structure of a direct precursor to C(18) are described. The analysis of laser flash heating experiments on this precursor by time-of-flight mass spectroscopy shows a sequence of retro-Diels-Alder reactions leading to C(18) as the predominant fragmentation pattern. Structural evidence is provided for the generation of an all-carbon molecule from a well-characterized organic precursor.     

The enigma of prokaryotic life in deep hypersaline anoxic basins

Deep hypersaline anoxic basins in the Mediterranean Sea are a legacy of dissolution of ancient subterranean salt deposits from the Miocene period. Our study revealed that these hypersaline basins are not biogeochemical dead ends, but support in situ sulfate reduction, methanogenesis, and heterotrophic activity. A wide diversity of prokaryotes was observed, including a new, abundant, deeply branching order within the Euryarchaeota. Furthermore, we demonstrated the presence of a unique, metabolically active microbial community in the Discovery basin, which is one of the most extreme terrestrial saline environments known, as it is almost saturated with MgCl2 (5 M).     

云南丽江地区角蒿属植物资源的初步调查

通过对云南丽江地区角蒿属植物资源的调查，初步摸清了丽江地区分布有角蒿属植物7个种、1个变种、1个变型，占云南省角蒿属种类的90％，中国的75％，世界的64．3％，是中国角蒿属植物资源的分布中心。同时对角蒿属植物的种质资源情况进行了分析和评价，提出了角蒿属植物的主要识别特点和分种检索表，并提出了合理开发利用和保护的建议。     

全国草原返青正常

<正>农业部草原监理中心采取地面观测、卫星遥感和结合气象资料分析的方法,对全国草原牧草返青状况进行了监测分析。结果显示:今年入春后草原地区气温回升较快,大部分牧草进入返青时间较常年偏早,但受后期低温影响,牧区草原返青进程偏慢、返青期拉长,部分牧区草原返青期有所推迟;截至5月20日,全国85%的草原已经返青,返青速度较常年大体相当,青藏高原和新疆高海拔区域草原返青晚于常年。一、气象状况     

强化应急演练 提升草原火灾应急处置能力——全国草原防火实战演练圆满结束

<正>8月23日,农业部草原防火指挥部在青海省海北藏族自治州举办了全国草原防火实战演练。农业部副部长、农业部草原防火指挥部总指挥于康震在演练活动上强调,各级草原防火部门要不断完善和落实草原火灾应急预案,认真组织开展实战演练和培训工作,强化应急队伍素质,切实提高扑火作战能力。于康震认为,这次全国草原防火实战演练准备充分、组织缜密、指挥