Preparation of Urea Nitrogen Adsorbent of Complex Type and Adsorption Capacity of Urea Nitrogen onto the Adsorbent

The urea nitrogen adsorbent of complex type, which consists of chitosan coated dialdehyde cellulose （CDAC） and immobilized urease in gelatin membrane （IE）, was prepared. The cellulose, the dialdehyde cellulose （DAC） and the CDAC were characterized by scanning electronic microscope. The results indicate that the cellulose C2-C3 bond was broken under the oxidation of periodate and it was oxidated to DAC. The DAC was coated with chitosan and the CDAC was obtained. The adsorption of urea nitrogen onto the adsorbent in Na2HPO4-NaH2PO4 buffer solution was studied in batch system. The effects of the experiment parameters, including degree of oxidation of CDAC, initial urea nitrogen concentration, pH and temperature, on the adsorption capacity of urea nitrogen onto the adsorbent at CDAC/IE weight ratio 10：1 were investigated. The results indicate that these parameters affected significantly the adsorption capacity. The adsorption capacity of urea nitrogen onto the adsorbent was 36.7 mg/g at the degree of oxidation of CDAC 88%, initial urea nitrogen concentration 600 mg/L, pH 7.4 and temperature 37℃.     

新型固氮菌肥——天生牌肥力高

天生牌肥力高固氮菌肥,是由中国科技开发院北京阳光高科技实业公司哈尔滨分公司生产的一种新型的具有固氮功能的生物肥料,素有“活肥”之称。它是用从自然界中采集的活性菌种,经科学方法组合、复壮、加工而生成的。肥力高含有作物所需的硫、钙、铜、钼、硼等微量元素。此肥中的固氮菌能把空气中游离态氮转化为氨态氮,便于作物直接吸收利用。其分泌物能把土壤中作物不能吸收的磷、钾转化为可溶性磷、钾,易于作物吸收。而且施用后土壤中有益微生物增加,有害微生物明显减少,致病菌受到抑制,还可减少瘁倒病、枯萎病等病害的发生。同时,…     

好氧固氮微生物进行厌氧固氮的机制

主要介绍了好氧固氮微生物,如好氧自生固氮菌、豆科植物共生的根瘤菌和固氮蓝藻解决有氧呼吸与厌氧固氮矛盾的机制。     

好氧固氮微生物的防氧保护作用

好氧固氮微生物需要通过有氧呼吸合成ATP,但是固氮作用却是在厌氧条件下的还原过程。好氧固氮细菌通过细胞结构保护、呼吸保护、构象保护及防氧屏障等保护固氮酶的活性,从而解决了好氧呼吸与厌氧固氮之间的矛盾,并使好氧固氮微生物在有氧环境中能进行有氧呼吸与厌氧固氮。     

水田中的有益杂草——满江红

满江红是一种水生的蕨类植物,是水稻田中的有益杂草。它的有益之处包括:叶片的空腔内有固氮作用的蓝藻与其共生,它通过自己奇特的固氮本领,将空气中的氮气变成氨供满江红使用,使满江红成了赫赫有名的“绿色肥源”;抑制其他杂草生长;良好的家禽饲料。     

光合细菌及其在养殖业中应用研究进展

本对光合细菌的固氮分子生物学，用于污水处理，产生H2及提取天然色素这几个领域的研究进展，特别是我国地光合细菌在养殖业中的应用研究进展进行综述。     

介绍两个小实验

1闪电固氮的模拟实验 闪电固氮也叫大气固氮或高能固氮,高中生物学教材中提到了这一现象,为了加以验证,我们学校的兴趣小组进行了如下模拟实验： 实验装置如上图所示。图中玻璃管直径为2cm、长20cm,钢针长约10cm,钢针两尖端相距约5cm。     

Science Letters：Alterations in seedling vigour and antioxidant enzyme activities in Catharanthus roseus under seed priming with native diazotrophs

An experiment was conducted on Catharanthus roseus to study the effect of seed treatments with native diazotrophs on its seedling growth and antioxidant enzyme activities. The treatments had significant influence on various seedling parameters. There is no significant influence on dry matter production with the diazotrophs, Azospirillum and Azotobacter. However, the vital seedling parameters such as germination percentage and vigour index were improved. Azotobacter treatment influenced maximum of 50% germination, whereas Azospirillum and Azotobacter were on par with C. roseus with respect to their vigour index. There was significant difference in the population of total diazotrophs. Azospirillum and Azotobacter between rhizosphere and non-rhizosphere soils of C. roseus had the same trend and were observed at various locations of the study. The activities of antioxidant enzymes such as superoxide dismutase （SOD）, peroxidase （POX） and catalase （CAT） were increased to a significant extent due to the treatment with diazotrophs.     

有毒气体实验的集约化设计

本文简要阐述了有毒气体实验集约化设计的目的意义,并就中学化学教材上几个典型的有毒气体实验作了集约化设计,使实验变得更便捷、安全、可靠、环保.     

能固氮的人

人体的生长发育和细胞更新需要氨基酸来构建自己的蛋白质,人体所需要的22种氨基酸,有8种氨基酸人体无法合成,需要从食物中获取。但人体能够合成的氮基酸也需要从食物中摄取含氮化合物作为原材料。