腐植酸多元复合肥的效应研究

本文是作者1992—1995年腐植酸多元复合肥的效应研究部分内容。系针对玉米、小麦需肥特点和土壤养分概况,通过多点田间试验筛选出腐植酸多元复合肥的最佳配方。试验结果表明:该肥料具有速效性和长效性,养分元素利用率高,小麦、玉米等作物可实现年周期一次投肥,节省工时,减少田间作业环节,节肥效果显著。能协调养分,培肥地力,作物生长发育增强,明显改善了作物构成因素,由于根系发达,长势稳健,抗逆性明显提高,小麦品质得到了改善。该肥料比习惯施肥,等养分无机复合肥均有显著的增产效果。比习惯施肥亩增产26％,比等养分无机复合肥增产11.76％,经济效益高,明显好于其它肥料。该肥料宜作基肥施用,苗期不必追肥。本文还讨论了该肥料对土壤肥力的影响。

高山林线形成机理及植物相关生理生态学特性研究进展

高山林线作为极端环境条件下树木生存的界限,由于其对气候变化的敏感性,在全球变化研究中得到了广泛关注。研究高山林线形成机理以及林线地带植物相关生理生态学特性成为预测未来气候变化条件下植被动态变化的出发点。对于高山林线形成机理研究主要关注两方面问题:(1)林线地带外界环境如何限制乔木生长和分布,其内在机理如何;(2)灌木及草本相对于乔木在林线地区有哪些生存优势,从乔木到灌木及草本生活型演变的功能及意义如何。综述了当前高山林线形成机理及相关生理生态特性的国内外最新研究成果,指出尽管温度(尤其是生长季低温)在全球尺度上能解释大部分高山区域林线的分布,但树木生长和生存受限的内在机理并没有弄清楚,目前主要存在"碳受限"以及"生长受限"假说两大争论焦点。另外,理论上受温度控制的高山林线对气候变化的响应表现出不同的模式,表明全球变化对林线分布和植被生长影响的复杂性和不确定性。因此,未来的研究应该关注影响林线地区植被生长的多种生理生态学过程,比如水分及养分利用过程,以及从乔木到灌木及草本生活型演变的功能意义,从而为林线形成机理以及对气候变化的响应提供更好的解释。

密度对刺槐幼苗生物量及异速生长模式的影响

刺槐(Robinia pseudoacacia)具有较强的生态适应性和抗逆能力,是黄土高原植被恢复和生态重建的主要优良树种之一(程积民等,2002;陈云明等,2002)。黄土高原地区刺槐人工林密度偏大,且多为低产林(余新晓等,1996;韩芯莲等,1996;2003)。王百田等(2005)认为黄土高原刺槐单木总生物量及各部分生物量都是密度的幂函数关系,但低密度林分和高密度林分的总生物量都比中间密度林分的总生物量高。种植密度不仅影响刺槐林地生物量,而且刺槐林地出现土壤干层的部分原因就是栽植密度过大(韩芯莲等,2003),其林地生产力的维持以及可持续生长成为林草植被建设中亟待解决的问题。植物密度对种群个体数量和生长的调控可以维持种群对资源的合理利用,保持种群的稳定性(Watkinson,1980)。因生长资源的强制分配,种植密度能引起植株个体间相互作用,密度增加导致植物种内竞争产生,使种群中单株生长量和生物量发生改变(李博等,2000)。竞争的实质是植物对地上光照和地下养分资源的利用,在共享资源有限的情况下竞争会导致植物个体生长量和存活率的降低(李博等,1998)。种内竞争对植物个体生长的影响,与植物“自疏法则”的...

浅析红松人工果材林生长和结实的外部影响因素

国家天然林保护工程的全面实施大大限制了红松林的木材采伐量,使林业部门及人员不能再单纯追求木材收获所带来的利益,而趋向于追求木材和种籽的双重效益。充分了解红松果材林生长和结实的影响因素是实现种材兼收的重要前提。本文对红松生长和结实的各种外部影响因素进行了归纳综述,分析了地理位置、立地条件、主要气象因素、自然灾害以及人为经营管理等各种外部影响因素与红松生长和结实的因果关系,对正确拟定经营方案,实现红松果、材丰产,提高林业部门的经济收入以及满足社会需求具有一定的理论和现实指导意义。

三江平原岗地白浆土水解酶活性和动力学特性对不同连作农作物的响应

作物种植会对农田生态系统产生一定的影响。大田试验条件下,在黑龙江省853农场岗地白浆土上连续6年种植玉米、大豆、小麦、水稻,研究了土壤理化性质以及土壤中与碳、氮、磷、硫元素转化相关的9种水解酶活性和动力学特性的响应;同时研究了不同作物种植对土壤脲酶、磷酸单酯酶、磷酸二酯酶、芳基硫酸酯酶及β-葡糖苷酶动力学特性的影响。结果表明,大豆连作土壤的有效氮、总碳、总氮、总磷和总硫含量都稍高;大豆处理土壤pH值略低,但其它三种作物种植下的土壤均呈微酸性,差异不显著。土壤水解酶动力学参数对种植作物的反应与表观活性的反应不一致。玉米连作土壤蛋白酶和磷酸单酯酶活性高于其它处理;小麦处理的磷酸二酯酶和芳基硫酸酯酶活性最高,水稻连作土壤蛋白酶、磷酸二酯酶和磷酸三酯酶活性最低。连年种植小麦处理的土壤脲酶、磷酸二酯酶以及芳基硫酸酯酶Vmax显著高于其它处理,小麦连作土壤β-葡萄糖苷酶、脲酶、磷酸二酯酶和芳基硫酸酯酶的Vmax/Km值显著高于其它处理,可以看出在此处理下土壤酶具有较强的催化潜势。

兴安落叶松林生产力模拟及其生态效益评估

以兴安落叶松林为研究对象 ,基于森林资源清查资料和气候资料 ,建立了反映森林生物学特性 (蓄积量和年龄 )和气候因素 (年均温和年均降水 )综合作用的兴安落叶松林现实生产力模型 ;同时 ,评估了兴安落叶松林的生态系统公益 ,指出我国兴安落叶松林的生态系统公益总价值约为 4499 8× 10 6美元·a-1,其中生态效益 (包括气候控制、土壤形成、废物处理、生物控制 )的价值达 2 816.1× 10 6美元·a-1,约占生态系统公益总价值的 62 6% ,是兴安落叶松林所创造的直接经济价值的 2 5 6倍 ,社会经济价值的 5 0倍 .这表明全球气候变化将对兴安落松林的影响巨大 ,迫切需要研究全球变化下的兴安落叶松林对策 .

再生植物纤维地膜的降解实验研究

介绍了再生植物纤维地膜降解的实验研究方法,检测分析了其干热老化实验结果,选择定量、抗张强度、伸长率为再生植物纤维地膜的追踪监测指标。在相同的田间实验环境条件下,以塑料地膜为参比,观测再生植物纤维地膜自然降解随时间变化的规律,为其降解的可控性提供实验依据。

Fluorene-Based Copolymers Containing Dinaphtho-s-indacene as New Building Blocks for High-Efficiency and Color-Stable Blue LEDs

By incorporating a new building block, 7,7,15,15-tetraoctyldinaphtho-s-indacene (NSI), into the backbone of poly(9,9-dioctylfluorene) (PFO), a novel series of blue light-emitting copolymers (PFO-NSI) have been developed. The insertion of the NSI unit into the PFO backbone leads to the increase of local effective conjugation length, to form low-energy fluorene-NSI-fluorene (FNF) segments that serve as exciton trapping sites, to which the energy transfers from the high-energy PFO segments. This causes these copolymers to show red-shifted emissions compared with PFO, with a high efficiency and good color stability and purity. The best device performance with a luminance efficiency of 3.43 cd . A(-1), a maximum brightness of 6 539 cd . m(-2) and CIE coordinates of (0.152, 0.164) was achieved.

Synthesis and properties of soluble poly[bis(benzimidazobenzisoquinolinones)] based on novel aromatic tetraamine monomers

Four aromatic tetraamine monomers possessing flexible ether linkages were successfully synthesized by nucleophilic aromatic substitution of hydroquinone, 4,4'-dihydroxybiphenyl, 2,2'-bis(4-hydroxyphenyl)propane, and 2,7-dihydroxynaphthalene with 5-chloro-2-nitroaniline, followed by reduction, respectively. With these monomers, a new class of soluble poly[ bis(benzimidazobenzisoquinolinones)] was prepared by a one-step, high-temperature solution polycondensation. The resulting polymers were completely soluble in phenolic solvents and had high inherent viscosities ranging from 1.2 to 1.5 g dL(-1). These polymers had glass transition temperatures in the range of 427-449 degrees C. Thermogravimetric analysis showed that all polymers were thermally stable, with 5% weight loss recorded above 510 degrees C in nitrogen.

Kinetics of Y(III) stripping for the system Y/HCl/Cyanex 272-P507/heptane with constant interfacial area cell with laminar flow

Kinetics and mechanism of stripping of yttrium(III) previously extracted by mixtures of bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272, HA), and 2-ethylhexyl phosphonic acid mono-2-ethylhexl ester (P507, HB) dissolved in heptane have been investigated by constant interfacial-area cell by laminar flow. The corresponding equilibrium stripping equation and equilibrium constant were obtained. The studies of effects of the stirring rate and temperature on the stripping rate show that the stripping regime is dependent on the stripping conditions. The plot of interfacial area on the rate has shown a linear relationship. This fact together with the strong surface activity of mixtures of Cyanex 272 and P507 at heptane-water interfaces makes the interface the most probable locale for the chemical reactions. The stripping rate constant is obtained, and the value is compared with that of the system with Cyanex 272 and P507 alone. It is concluded that the stripping ability with the mixtures is easier than that of P507 due to lower the activation energy of the mixtures. The stripping rate equation has also been obtained, and the rate-determining steps are the two-step interfacial chemical reactions as predicted from interfacial reaction models.

Determination of purity and molecular weight of calmodulin by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

The purity and molecular weight of calmodulin have been determined by means of matrix-assisted laser desorption/ionization time of flight mass spectrometry, and the results have been discussed. The experimental results demonstrate that this method is high sensitive and rapid as compared with other traditional methods.

用基质辅助激光解吸电离飞行时间质谱法测定钙调蛋白的纯度与分子量

采用基质辅助激光解吸电离飞行时间质谱法测定了钙调蛋白的纯度与分子量,并对所得的结果进行了讨论,实验结果表明本方法具有灵敏度高、分析速度快、重复性好、信息直观等特点,是其他传统测定蛋白质分子量的方法无法比拟的.