长白山阔叶红松林生态系统碳动态及其对气候变化的响应

应用基于干物质生产理论的过程模型(Sim-CYCLE)估算了1982—2003年间长白山阔叶红松林生态系统总第一生产力(GPP)、净第一生产力(NPP)、净生态系统生产力(NEP)及其季节动态变化以及碳储量(WE)、植物碳储量(WP)和土壤碳储量(WS),并分析了这些指标在当前气候情景和碳平衡情况时的差异及其对未来气候变化情景的响应.结果表明:在当前气候情景下,长白山阔叶红松林GPP、NPP和NEP分别为14.9、8.7和2.7Mg C·hm-2·a-1,三者分别比实测值减少2.8Mg C·hm-2·a-1、增加1.4Mg C·hm-2·a-1和增加0.2Mg C·hm-2·a-1;长白山阔叶红松林6—8月的NEP占全年总量的90%以上,其中,7月最高(1.23MgC·hm-2·month-1);研究区WE、WP和WS分别为550.8、183.8和367.0Mg C·hm-2,其与实测值均具有较高的一致性.从当前气候情景下到达碳平衡前,长白山阔叶红松林碳储量均有不同程度的增加,GPP和NPP分别为17.7和7.3Mg C·hm-2·a-1,表明研究区碳"汇"的作用随着碳储量的增加逐渐减弱;温度增加2℃时,不利于长白山阔叶红松林GPP、NPP和NEP的增长,CO2浓度倍增则可有利地促进三者的增长,CO2浓度倍增、温度增加2℃对GPP、NPP和NEP增幅的影响与单纯CO2浓度倍增的影响相似,气候变化情景对长白山阔叶红松林碳储量的影响规律与对生产力幅度的影响相同,这可能是生态系统生产力影响碳积累所致.

康氏木霉产酶发酵固体培养基优化研究

为利用廉价的培养基生产纤维素酶复合制剂,本实验采用培养基配方选择试验和双温度培养法对康氏木霉F244产酶特性进行了研究.在测定滤纸酶(FPA)、棉花酶、羧甲基纤维素酶(CMCase)、β-葡萄糖苷酶和果胶酶活力的基础上利用SPSS建立回归方程,全相关系数分别达到0.852,0.941,0.964,0.703,0.899,而后通过无约束规划求解找到最佳配方,并对酶活进行了预报和对比.结果表明:各酶活最大时对培养基各成分的含量要求不同;应用稻草粉质量分数20.3％,麸皮质量分数26.1％,(NH4)2SO4质量分数7.9％,水分质量分数45.7％的配方发酵时,F244的FPA、棉花酶、CMCase、β-葡萄糖苷酶、果胶酶活可望达14.1,20.1,43.9,21.6,16.8 IU/g,基本与里氏木霉Q9414在其推荐培养基上的产酶水平相当,而且该配方用料来源广泛,成本低廉,工艺简单,产品安全无毒.

黄土丘陵区藓结皮生物量测定方法及其随发育年限的变化

通过野外调查黄土丘陵区不同发育年限退耕地上藓结皮发育状况,结合室内测定,提出了藓类植物生物量测定的回归方程法.运用该方法测定了研究区9个不同发育年限藓类植物的生物量,并分析了其随发育年限的变化趋势.结果表明,研究区藓类植物个体微小,株高相同的藓类植物生物量变异很小,不同株高的藓类植物的株数与其生物量之间呈显著的线性相关关系(R2>0.96,n=7).因此,可以利用藓类植物株数与生物量之间的统计回归关系式估测生物结皮中藓类植物的生物量.用所建立的回归方程估测的研究区不同年限退耕地藓类植物生物量的绝对误差为1.3%～27.3%.研究区藓类植物生物量随结皮发育年限而变化,在退耕的前11年里,藓类植物生物量随发育年限的延长而增加,至11年时藓类植物生物量达到最大值(303.8g/m2),此后藓类植物生物量变化不大甚至还有下降趋势.

两种匍灯藓属植物夏季和冬季光合特性的比较研究

分别对生长于冬季和夏季的五倍子蚜虫冬寄主藓类植物湿地匍灯藓 (Plagiomniumacutum (Lindb .)T .Kop .)和侧枝葡灯藓 (Plagiomniummaximoviczii(Lindb .)T .Kop .)的净光合速率及其与光照、温度的关系进行了比较研究 .结果表明 ,2种藓类的最大光合能力在夏季分别为 12 5 6 7和 94 6 3μmolCO2 ·kg-1DW·s-1,而在冬季只有 5 8.1和 6 2 .1μmolCO2 ·kg-1DW·s-1;其暗呼吸强度夏季也比冬季显著增强 ;光补偿点均在 2 0～40 μmol·m-2 ·s-1,光饱和点在 2 0 0～ 40 0 μmol·m-2 ·s-1之间 ,夏季比冬季略高 .它们在夏季的表观量子效率分别为 1 5 35和 1 5 5 9,冬季只有 0 45 6和 0 45 9.光合最适温度在 2 0～ 35℃之间 ,夏季比冬季有所升高 .在 0～ 2 0℃条件下测得的温度系数 ,在不同季节和不同种类均相似 ,约在 1 15～ 1 2 3之间 .它们对高温和低温都表现出一定的抗性 ,在 -15～ -10℃的低温以及 40～ 45℃的高温条件下均能够保持一定的净光合速率

辽东山区长白落叶松(Larixolgensis)种子雨和种子库

长白落叶松是东北地区主要的用材树种,其种子雨和种子库研究鲜见报道。在辽东山区用收集器收集的种子分析了长白落叶松种子雨组成、质量和扩散距离,每隔2个月调查1次种子库数量,并结合靛蓝染色法测定每次种子的活力来分析土壤种子库动态。结果表明,辽东山区的长白落叶松种子雨从8月中旬开始,9月末到10月初达到高峰期,11月初结束。在起始期,种子雨以干瘪的不完整种子为主,而从高峰期开始,种子雨以完整种子为主。整个长白落叶松种子雨中不完整种子约占种子雨总量的45%,这些不完整种子由被动物取食、空粒和病虫害危害种子组成。完整种子的平均生活力为56.4%,即有活力的种子仅占整个种子雨的30%。种子雨集中在母树周围,在林缘1次扩散距离一般不超过1.5倍树高。种子雨到达地面之后,主要分布在枯枝落叶层,土壤0~5cm层有少量分布,土壤5 cm以下没有种子分布;土壤种子库的种子主要在翌年雪融化后开始萌发、被取食、搬运以及腐烂,其中腐烂种子数占45.4%,动物取食为30.0%。种子库的种子数量和活力在冬季没有明显变化,而在翌年,种子数量和活力明显减少,4、6月和8月份种子数量分别为(506.3±35.56)粒m-2,(267.1±17.47)粒m-2和(143.6±9.83)粒m-2,对应的活力分别为47.8%±4.68%,19.4%±3.39%和0%,这表明长白落叶松种子不能在地面形成连续的种子库。

黄土高原主要土壤锌有效性及其影响因素

通过测定黄土高原不同区域、不同类型土壤全锌和有效锌含量,研究了黄土高原土壤锌含量及影响有效锌的因素。结果表明,供试土壤全锌主要分布在50～100mg·kg-1之间,有效锌含量较低,其中20.69%在临界值(0.5mg·kg-1)之下,37.93%为低(0.5～1.0mg·kg-1)水平。用直线、幂函数和指数函数回归方程对影响有效锌的主要土壤因素进行回归拟合。发现土壤有效锌与全锌、全氮、全磷、有机质呈显著正相关,与土壤pH值呈显著负相关;幂函数可以较好地拟合有效锌与土壤全氮、有机质的相关关系,有效锌与全锌、全磷、pH值宜用指数函数表示其相关性。通径分析表明土壤性质对有效锌的直接作用系数大小次序为全氮>全锌>pH>全磷,土壤全氮对锌有效性的直接作用最明显。

玉米地膜覆盖的土壤环境效应

通过田间试验研究了地膜覆盖和露地栽培对玉米的土壤温度、水分、养分、盐分含量和土壤生物学特性及硝酸盐含量的变化。结果表明,在玉米生长前期,地膜覆盖5,10,15,20,25 cm土层的土壤日平均温度比露地提高2.4℃、3.0℃、2.9℃、2.2℃、2.7℃,6~7月份比露地降低1.1℃、0.5℃、0.5℃、0.6℃、0.6℃。地膜覆盖0~10,10~20,20~30,30~40 cm土层的土壤含水量分别比露地增加18.84%、10.67%、11.12%和8.9%。地膜覆盖增强了土壤蔗糖酶和碱性磷酸酶的活性,增加了土壤微生物的数量、CO2浓度、土壤呼吸和土壤NO3--N的含量,减少了土壤氮素的损失。地膜覆盖降低了土壤有机质、氮素、速效磷的含量、过氧化氢酶和脲酶的活性及土壤表层的盐分含量。地膜覆盖提高了玉米的生物量和经济产量。

饲用复合酶对肉鸡生产性能的影响

本研究旨在探讨应用复合酶提高肉鸡生产性能与适当降低代谢能及蛋白,使加酶后的饲料配方更趋合理。试验中对照组喂常规肉鸡浓缩料,试验1组喂加酶常规肉鸡浓缩料,试验2组喂加酶减豆粕浓缩料,三组中的玉米添加比例相同,调饲料配方后的1t浓缩料可降低成本126元。试验结果表明,试验1组与试验2组分别比对照组提高肉鸡增重9.4%与6.3%,经济效益提高24.3%与14.1%。

Entangled metal-organic frameworks modulated by N-donor ligands of different conformations

Based on the aromatic dicarboxylic acid and N-donor ligands with different conformations, four Zn(II) metal-organic frameworks, namely [Zn(mfda)(L-1)](1), [Zn-2(mfda)(2)(L-2)]center dot DMF center dot H2O (2), [Zn-2(mfda)(2)(L-3)(H2O)]center dot DMF (3) and [Zn-2(mfda)(2)(L-4)] (4) have been synthesized (mfda = 9,9-dimethylfluorene-2,7-dicarboxylate anion, L-1 = 1,10-phenanthroline, L-2 = 4,4 '-bipyridine, L-3 = 2,5-bis(4-pyridyl)-1,3,4-ocadiazole and L-4 = 1,4-bis(imidazol-1-ylmethyl)benzene). Single-crystal X-ray diffraction has revealed that all compounds exhibit entangled structures. Compound 1 is composed of 1D zigzag chains that are entangled through the pi-pi stacking interactions to generate a three-fold interpenetrating diamond-like networks.

Polymerization of 1,3-butadiene with VO(P-204)(2) and VO(P-507)(2) activated by alkylaluminum

The oxovanadium phosphonates (VO(P-204)(2) and VO(P-507)(2)) activated by various alkylaluminums (AlR3, R = Et, i-Bu, n-Oct; HAIR(2), R = Et, i-Bu) were examined in butadiene (Bd) polymerization. Both VO(P-204)(2) and VO(P-507)(2) showed higher activity than those of classical vanadium-based catalysts (e.g. VOCl3, V(acac)(3)). Among the examined catalysts, the VO(P-204)(2)/Al(Oct)(3) system (I) revealed the highest catalytic activity, giving the poly(Bd) bearing M-n of 3.76 x 10(4) g/mol, and M-w/M-n ratio of 2.9, when the [Al]/[V] molar ratio was 4.0 at 40 degrees C. The polymerization rate for I is of the first order with respect to the concentration of monomer. High thermal stability of I was found, since a fairly good catalytic activity was achieved even at 70 degrees C (polymer yield > 33%); the M-n value and M-w/M-n, ratio were independent of polymerization temperature in the range of 40-70 degrees C. By IR and DSC, the poly(Bd)s obtained had high 1,2-unit content (> 65%) with atactic configuration. The 1,2-unit content of the polymers obtained by I was nearly unchanged, regardless of variation of reaction conditions, i.e. [Al]/[V], ageing time, and reaction temperature, indicating the high stability of stereospecificity of the active sites.

Syntheses and crystal structures of [Mn(H2O)(4)(bpy)]L center dot 4H(2)O, [Mn(H2O)(4)(bpy)]L ' center dot 4H(2)O (H2L = SUCCINIC ACID, H2L ' = FUMARIC ACID)

Reactions of freshly prepared M(OH)(2-2x)(CO3)(x) (.) yH(2)O (M = Mn, Zn) and 4,4'-bipyridine (bpy) with succinic acid (H2L) or famaric acid (H2L') in CH3OH-H2O afforded [Mn(H2O)(4)(bpy)]L (.) 4H(2)O, 1, [Mn(H2O)(4)(bpy)]L' (.) 4H(2)O, 2 and [Zn(H2O)(4)(bpy)]L (.) 4H(2)O, 3. The three coordination polymers are isostructural and consist of (1)(infinity)[M(H2O)(4)(bpy)(2/2)](2+) cationic chains, crystal H2O molecules and dicarboxylate anions (succinate or fumarate anions). Within the chains, the metal atoms are each octahedrally coordinated by four aqua oxygen atoms and two pyridyl nitrogen atoms from two 4,4'-bipyridine ligands. The crystal H2O molecules are hydrogen bonded to dicarboxylate anions to form ribbon-like anionic chains. The cationic and anionic chains are interconnected via hyqrogen bonds to generate a 3D network. Crystal data: 1 triclinic, P (1) over bar, a = 7.235(1), b = 7.749(2), c = 10.020(2) Angstrom, alpha = 79.95(3), beta = 88.79(3), gamma = 71.39(3)degrees, V = 523.9(2) Angstrom(3) and D-cal = 1.494 g cm(-3) for Z = 1; 2 triclinic, P (1) over bar, a = 7.127(1), b = 7.800(2), c = 9.945(2) Angstrom, alpha = 80.26(3), beta = 87.86(3), gamma = 72.69(3)degrees, V = 520.2(2) Angstrom(3) and D-cal = 1.498 g cm(-3) for Z = 1; 3 triclinic, P (1) over bar, a = 7.189(1), b = 7.764(2), c = 9.843(2) Angstrom, alpha = 79.16(3), beta = 87.80(3), gamma = 71.29(3)degrees, V = 510.9(2) Angstrom(3) and D-cal = 1.559 g cm(-3) for Z = 1.

Investigation of sandwiched gadolinium(III) complexes with tungstosilicates as potential MRI contrast agents

Two gadolinium-sandwiched complexes with tungstosilicates, K-13[Gd(SiW11O39)(2)] (Gd(SiW11)(2)) and K11H6[Gd2O3(SiW9O34)(2)] (Gd-3(SiW9)(2)), have been investigated by in vitro and in vivo experiments as potential contrast agents for magnetic resonance imaging (MRI). T-1-relaxivity of Gd(SiW11)(2)was 6.59 mM(-1) . s(-1) in aqueous solution and 6.85 mM(-1) . s(-1) in 0.725 mmol . L-1 bovine serum albumin solution at 25degreesC and 9.39 T, respectively. The corresponding T-1-relaxivity of Gd-3(SiW9)(2) was 12.6 and 19.3 mM(-1) . s(-1) per Gd, respectively. MRI for Sprague-Dawley rats showed longer and more remarkable enhancement in rat liver after i.v. injection of these two complexes: 39.4 +/- 3.9% and 57.4 +/- 11.6% within the first 30 min after injection, 31.2 +/- 2.6% and 39.9 +/- 7.6% in the next 60 min for Gd(SiW11)(2) and Gd-3(SiW9)(2) at doses of 0.081 and 0.084 mmol Gd/kg, respectively. Our preliminary in vitro and in vivo study indicates that Gd(SiW11)(2) and Gd-3(SiW9)(2) are favorable candidates for hepatic contrast agents for MRI. However, the two complexes exhibit higher acute toxicity and need to be modified and studied further before clinical use.

Green electroluminescent polyfluorenes containing 1,8-naphthalimide moieties as color tuner

A series of copolymers (CNPFs) containing low-band-gap 1,8-naphthalimide moieties as color tuner was prepared by a Yamamoto coupling reaction of 2,7-dibromo-9,9-dioctylfluorene (DBF) and different amount of 4-(3,6-dibromocarbazol-9-yl)-N-(4'-tert-butyl-phenyl)-1,8-naphthalimide (Br-CN) (0.05-1 mol% feed ratio). The light emitting properties of the resulting copolymers showed a heavy dependence on the feed ratio. In photoluminescence (PL) studies, an efficient color tuning through the Forster energy transfer mechanism was revealed from blue to green as the increase of Br-CN content, while in electroluminescence (EL) studies, the color tuning was found to go through a charge trapping mechanism. It was found that by introduction of a very small amount of Br-CN (0.1-0.5 mol%) into polyfluorene, the emission color can be tuned from blue to pure green with Commission International de l'Echairage (CIE) coordinates being (0.21, 0.42) and (0.21, 0.48). A green emitting EL single-layer device based on CNPF containing 0.1 mol% of Br-CN showed good performances with a low turn-on voltage of 4.2 V, a brightness of 9104 cd/m(2), the maximum luminous efficiency of 2.74 cd/A and the maximum power efficiency of 1.51 lm/W.

New neutral nickel(II) complexes bearing pyrrole-imine chelate ligands: synthesis, structure and norbornene polymerization behavior

New neutral nickel(II) complexes bearing nonsymmetric bidentate pyrrole-imine chelate ligands (4a-d), [2-(ArNCH)C4H3N]Ni(PPh3)Ph [Ar=2,6-diisopropylphenyl (a), 2-methyl-6-isopropylphenyl (b), 2,6-diethylphenyl (c), 2-tert-butylphenyl (d)], have been prepared in good yields from the sodium salts of the corresponding ligands and trans-Ni(PPh3)(2)(Ph)Cl, and the structure of complex 4a has been confirmed by X-ray crystallographic analysis. These neutral Ni(II) complexes were investigated as catalysts for the vinylic polymerization of norbornene. Using modified methylaluminoxane (MMAO) as a cocatalyst, these complexes display very high activities and produce great mass polymers. Catalyst activity of up to 4.2 x 10(7) g (mol Ni h)(-1) and the viscosity-average molecular weight of polymer of up to 9.2 x 10(5) g mol(-1) were observed. Catalyst activity, polymer yield, and polymer molecular weight can be controlled over a wide range by the variation of reaction parameters such as Al-Ni ratio, norbornene-catalyst ratio, monomer concentration, polymerization reaction temperature and time.

Kinetic analysis of TNF immune complex by using surface plasmon resonane

The kinetic analysis of the interaction between tumor necrosis factor(TNF) and its monoclonal antibody was performed by surface plasmon resonance(SPR) technique. The monoclonal antibody was immobilized to the surface of CM5 sensor chip by amine coupling. TNF at different concentrations was injected across the mAb immobilized surface. The interaction was recorded in real time and could be seen on the sensorgram. One cycle, including association, dissociation and regeneration, lasted no more than 15 min. The interaction results was evaluated using 1 : 1 Langmuir binding model. The kinetic rate constants were calculated to be: k =1.68 X 10(3) L (.) mol(-1) (.) s(-1), k(d) = 1.73 X 10(-4) s(-1), and the affinity constants K-A = 9. 7 X 10(3) L (.) mol(-1), K-r)= 1. 03 X 10(-7) Mol (.) L-1. The X-2 was 3.47, which showed that the interaction is consistent with the 1 : I model. We can see from the results that although there are two binding sites in one mAb molecule, TNF reacts with each site in an independent and noncooperative manner.