不同施肥方式下土中有机氯农药的残留特征

Soil samples with three fertilization treatments (no fertilizer, corn straw and farm manure) collected from a Lou soil (Eum-orthic Anthrosol classfied using Chinese Soil Taxonomy) in northwestern China were analysed for residual levels and their characteristics of organochlorine pesticides (α-HCH, β-HCH, γ-HCH, δ-HCH, HCB, o,p'-DDT, p,p'-DDT, o,p'-DDE, p,p'-DDE, p,p'-DDD, a-endosulfan, dieldrin and endrin). Organochlorine pesticides (OCPs) were detected in all soil samples except δ-HCH and their total concentrations ranged from 159.31 ± 9.00 to 179.77 ± 2.58 ng g^-1 with an order of HCHs > DDTs > (dieldrin + endrin) > HCB > α-endosulfan. Among all the compounds, γ-HCH had the highest concentration followed by p,p'-DDE. The residual levels of HCH isomers and DDT as well as their metabolites in soil with different fertilization treatments were in the order of γ-HCH > β-HCH ≈ α-HCH > δ-HCH and p,p'-DDE > p,p'-DDT > o,p'-DDT > p,p'-DDD ≈ o,p'-DDE, respectively. DDE/DDT ratios ranged from 1.59 ±0.13 to 3.35 ± 0.16 and endrin/dieldrin ratios from 1.40 ± 0.06 to 9.20 ± 4.05, both indicating no new occurrence of these pesticides in these soils, while α-HCH/γ-HCH ratios of 0.04 indicated a new input of lindane (almost pure γ-HCH) in the past several years. The farm manure treatments showed lower DDT residues than samples without fertilizer. Also addition of corn straw and farm manure increased soil organic matter content and decreased the soil pH which could retard the degradation of DDT in the soil.     

水分胁迫下李树叶绿素荧光动力学特性研究

水分胁迫引起李树叶片叶绿素含量(CHL)、相对含水量(LRWC)下降,叶绿素荧光参数Fo升高,Fm、Fv、Fv/Fm、Fv/Fo、Fm/Fo和Fo与Fm曲线之间面积降低,表明水分胁迫影响了光系统Ⅱ光化学效率、潜在活性、捕获激发能的效率、光合电子的传递以及电子受体库的大小,从而导致光合速率下降。3个供试品种中以“索瑞斯”受影响最小,“秋姬”居中,“安哥洛”最大,说明“索瑞斯”抗旱性最强。     

黄土半干旱区刺槐林地土壤蒸发特性研究

对黄土半干旱区刺槐林内的土壤蒸发状况,进行比较系统的试验研究。试验采用微型蒸发器（Micro-lysimeters,MLS）,人为控制土壤水分梯度,对不覆盖、枯枝落叶物覆盖和苔藓覆盖3种处理的林地土壤蒸发进行了分析。结果表明,在不同土壤水分条件下,利用枯落物覆盖减小林地土壤蒸发效果晴天好于多云天,枯落物覆盖、苔藓覆盖与无覆盖相比,分别减少了20.15%～52.46%和11.11%～36.72%的土壤蒸发,枯落物覆盖效果好于苔藓;林地土壤蒸发量随土壤水分的增加呈上升趋势,当土壤含水量增加到一定临界值以后,林地土壤蒸发量由上升变为下降,表现出土壤水分对林地土壤蒸发具有明显的阈值反应,土壤含水量的临界值分别为14.2%（枯落物覆盖）和16.8%（不覆盖）;基于林地土壤蒸发量（E1）与水面蒸发量（E0）的观测数据,利用STATISTICA软件统计分析,建立林地土壤蒸发模型,可用于林地土壤蒸发量的估算,为林地土壤水分管理提供理论依据。     

水稻籼爪交和粳爪交杂种优势的研究:Ⅲ.籼爪交杂种品质性状的表现

研究了长沙和三亚生态条件下籼爪交和对照杂交稻品质性状的表现。籼爪交杂交稻在长沙的整精米率极显著低于对照。垩白粒率显著低于对照，精米长、精米长宽比均显著大于对照；而在三亚的精米长、精米长宽比极显著大于对照。籼爪交杂交稻在三亚垩白面积率比长沙极显著变小、蛋白质含量显著升高。对照组合在三亚表现为整精米率、垩白面积率和胶稠度显著降低。     

非对称性增温对冬小麦强势粒和弱势粒淀粉合成关键酶活性的影响

以扬麦11为材料,采用全生育期田间开放式增温系统进行增温处理,研究了不同增温处理对小麦强和弱势粒淀粉合成关键酶活性的影响差异。结果表明,冬小麦强势粒中蔗糖合酶(SS)、腺苷二磷酸葡萄糖焦磷酸化酶(AGPase)和淀粉分支酶(SBE)的活性较弱势粒高,而且三者白天的活性均比夜间高。不增温条件下,整个灌浆期强势粒中SS、AGPase和SBE的活性平均分别比弱势粒高72.9%、111.4%和7.8%。全天、白天和夜间增温条件下,强势粒SS白天的活性比常温对照的高8.4%~31.2%,夜间的活性比对照高11.1%~20.3%;弱势粒SS白天的活性比对照高9.7%~20.3%之间,夜间的活性比对照高6.1%~32.0%。弱势粒中AGPase活性在不同增温处理下也显著提高,其白天的活性比对照高54.2%~124.4%,夜间的活性比CK高20.7%~99.3%。增温对SBE活性的影响较小,强势粒和弱势粒在增温条件下其白天的活性均比对照高3.9%~12.1%,夜间的活性均比对照高1.0%~7.6%。相关分析表明,AGPase和SBE的活性与千粒重之间存在极显著正相关,增温条件下AGPase和SBE的活性显著提高,尤其是弱势粒中AGPase和SBE活性的显著提高是千粒重提高的一个重要原因。     

兴义坡岗自然保护区草本观赏植物资源研究

对兴义坡岗自然保护区草本观赏植物的研究,得出具有观赏价值的植物54科136属267种.并对其按观赏类型和用途进行了分类,为开发利用这些草本观赏植物提供依据.     

黑稻CHS基因外显子Ⅱ部分序列遗传变异分析

以汉中栽培2种黑稻(黑丰,黑米B)和1种白稻(香粘)为材料,根据水稻查尔酮合成酶(chalcone synthase,CHS)基因DNA序列的保守区域设计3对引物,进行PCR扩增,获得CHS外显子Ⅱ部分序列,测序并与籼稻CHS基因(X 89589.1)比对,发现有13处SNP,这些SNP可能是黑稻种子黄酮类物质含量差异的重要原因之一.稻和其他植物CHS基因外显子Ⅱ序列的进化分析表明,CHS基因虽然整体上反映进化关系,但由于不同基因的进化历史不同,因此单独用CHS基因的进化树来反映物种的进化关系是不确切的,而应尽量选择多位点进行研究.研究结果为高黄酮类物质含量的黑稻育种和黑稻CHS基因在分子系统分类方面提供了必要数据.     

习水国家级自然保护区四川大头茶群落研究

以习水国家级自然保护区天然四川大头茶群落为调查研究对象,分析了群落的物种组成、外貌特征和结构特征,定量计测了乔木层主要树种的群落特征指标.结果表明,习水自然保护区四川大头茶群落植物共有31科49属53种;垂直结构明显,分为乔木层、灌木层、草本层,乔木层的物种多样性指数较高,物种丰富;四川大头茶在群落中处于优势种地位;群落结构趋于稳定.     

Removal of Dmethyl Phthalate from Water with Enhanced Coagulation Technology

The removal of Phthalate Esters (PAEs) from water was measured by using enhanced coagulation technology.Cationic coagulant poly-diallyl-dimethyl-ammonium-chloride (PDMDAAC) and polyacrylamide (CPAM) were employed to remove the dimethyl phthalate (DMP),and the residual concentration of DMP is determined by the high performance liquid chromatography (HPLC).During the coagulation/flocculation process,parameters such as coagulant dosage,pH value,and sedimentation time are investigated.The results show the use of coagulant PDMDAAC/CPAM together has better coagulation effect than PDMDAAC.DMP removal rate is 99.87% when initial DMP concentration is 0.50 mg/L,the addition of a PDMDAAC dosage 50 mg/L,the addition of a CPAM dosage 2.5 mg/L,pH value 6.0 and sedimentation time 3 hours.Therefore,the removal of PAEs by coagulation is effective,and the application of coagulation by PDMDAAC/CPAM in water supply will enhance the removal of PAEs and at the same time reduce the water turbidity.     

Improvement of circulatory circle design method forautomobile hydraulic torque converters

A design method to reduce the circulatory circle axle size for automobile hydraulic torque converters is proposed. According to the beam flow theory, the variety of the axle size has little effect on the characteristics of torque converters. Based on analyzing traditional design method, it’s found that the basic reason for oversize of axle is the unreasonable semi-empirical expression of the first and third arc radius. An improved design semi-empirical expression is proposed for passage car torque converters based on the analysis of several foreign mature torque converters, and an improved design method is established. The improved method is used to design a torque converter, and the results show that the circulation circle axle size reduces about 26% in the condition of keeping the same characteristics of the traditional method. It means the improved design method can better meet the design requirement of automobile torque converters.