Addition of HPMA affects seed germination, plant growth and properties of heavy saline-alkali soil in northeastern China: comparison with other agents and determination of the mechanism

China has a large area of inland saline-alkali land, equivalent to 40% of the total cultivated land in the country. The principal features of these lands are high salt content, high pH, and poor soil structure with low water infiltration and poor drainage. These conditions effectively prevent the exploitation of such land for agriculture. In this study, we have compared 17 soil conditioning agents for their abilities to promote seed germination and growth under both laboratory and field conditions. One of these, Hydrolyzed Polymaleic Anhydride (HPMA), was identified as a highly effective agent for soil improvement. Laboratory germination experiments and laboratory and field cultivation of a variety of plants both showed that addition of HPMA could significantly increase the germination percentage and plant growth rate. Distinct from other Ca-carrier agents such as gypsum, HPMA increases the dissolution of CaCO₃, which is abundant in the calcareous saline-alkali soils. This allows Ca²⁺ in soil solution to displace the over-abundant Na⁺ in the soil colloids. This process greatly improves soil properties such as the bulk density, which decreased, and the capillary soil rise height of water and soil water infiltration rate, which increased. Direct SEM and AFM imagery showed flocculent soil precipitation (soil aggregates) after HPMA addition, and a looser structure of those aggregates. The addition of HPMA also reduced the soil pH and EC. These changes in soil chemical and physical properties are a likely explanation for the soil improvement effected by HPMA. The high content of insoluble CaCO₃ in saline-alkali land such as that in northeastern China (up to 13%) favors the further exploration of HPMA as an ameliorative agent.     

Positive selection vector using the KillerRed gene

Plasmid pZK18S is a novel positive selection vector containing the genetically encoded photosensitizer KillerRed as the selection marker. When transformed into host cells (lacI^q or lacI⁺), the common medical surgical light is sufficient to activate phototoxicity of KillerRed. Thus, only the recombinants with disrupted reading frame of KillerRed genes finally allow forming viable colonies. Because lethality of KillerRed relies on light irradiation, no special host and culture medium are required to amplify and prepare pZK18S vector in larger quantities. The pZK18S was reliable and highly efficient for constructing the serial analysis of gene expression (SAGE) library.     

‘津田’芜菁Transparent Testa Glabra 1（BrTTG1）基因的克隆及表达分析

TTG1（Transparent Testa Glabra 1）蛋白是一种WD40类蛋白,参与植物的生长和发育。采用RT-PCR方法从芜菁品种‘津田＇中克隆了BrTTG1 cDNA序列（GenBank登录号HM208590）。该基因cDNA开放阅读框长度为1 014 bp,编码一个由337个氨基酸残基组成的蛋白,该蛋白分子量为37.28 kDa,理论等电点为4.66。与其他植物中的TTG1蛋白进行同源性比对结果显示,BrTTG1与甘蓝型油菜的TTG1同源性最高。BrTTG1蛋白在31～337位氨基酸处含有WD40超家族的保守结构域。荧光定量PCR检测BrTTG1在‘津田＇芜菁不同组织中的表达结果表明,该基因在有花青素合成的红色‘津田＇芜菁根皮中表达量最高。     

扎龙湿地昆虫群落结构及动态

湿地是介于水体与陆地之间的特殊的生态系统,其中昆虫扮演着重要的角色。通过选取扎龙村、烟筒屯、土木台和育苇场为样地以诱集夜间活动的昆虫为主,对扎龙湿地昆虫群落结构进行了探讨。结果表明:扎龙湿地夜间活动的昆虫分属14目54科139种,以鳞翅目、鞘翅目和双翅目为优势类群。各区域昆虫群落种-多度关系均表现为对数正态分布。物种丰富度为扎龙村＞烟筒屯＞育苇场＞土木台,而群落多样性和均匀度均为烟筒屯＞扎龙村＞土木台＞育苇场,Shannon-Wiener 多样性指数(H') 与均匀度(J')和物种丰富度(S)时间动态关系表现为:烟筒屯Shannon-Wiener 多样性指数(H')与均匀度(J')和物种丰富度(S)均一致;扎龙村和育苇场Shannon-Wiener 多样性指数(H')与均匀度(J')一致,而与物种丰富度(S)弱相关;土木台 Shannon-Wiener 多样性指数(H')与均匀度(J')和物种丰富度(S)均表现为弱相关。研究得出扎龙湿地总体环境质量较好,但局部地区(如土木台)有退化的趋势,并分析造成上述结果的原因。     

哺乳动物毛被传热性能及其影响因素

毛被能够加强或减弱动物向周围环境的热量散失,毛被的形态结构和颜色是传热性能的决定因素,其传热过程往往是传导、对流和辐射3个过程的耦合。以往研究发现环境因子中,风可增加机体向环境中的散热速率,且散失量与风速正相关,且动物通过调节在风场中的姿态来适应不同风向。动物体与环境间的温差是影响散热速率的另一因素,不同环境中的动物通过改变毛被结构来适应温差变化。毛被含水率上升会引起导热和蒸发冷却作用加强,动物通过行为或毛被结构变化来调节毛被含水率。毛色决定毛被吸收和反射热辐射的能力。毛被传热性能直接把动物的生理特点与环境因子关联起来,这对揭示动物的适应、进化都具有重要意义。同时提出,毛被结构和传热性能的研究还有助于仿生学意义的挖掘。因此,今后应重点在毛被结构和物理性能、研究技术与方法以及毛被生物学和仿生学意义等方面开展研究。     

我国东北土壤有机碳、无机碳含量与土壤理化性质的相关性

根据黑龙江、吉林、辽宁省和内蒙古地区相关历史资料数据,分析了我国东北表层土壤(0-50 cm)土壤相关理化性质与有机碳、无机碳的相关性,得到如下结论:土壤全氮、碱解氮、全磷、速效磷、速效钾、K⁺离子交换量、Fe₂O₃、P₂O₅、总孔隙度均与土壤有机碳含量呈显著正相关(R²=0.10-0.94, n=38-345, P<0.0001),但与土壤无机碳含量则大多呈显著负相关(R²=0.11-0.30, n=37-122, P<0.01);与此相反,土壤pH值、容重与土壤有机碳呈负相关(R²=0.36-0.42,n=41-304, P<0.0001),而与无机碳呈显著正相关(R²=0.29-0.31,n=39-125, P <0.01)。表层土壤有机碳、无机碳与土壤理化性质呈相反变化趋势的结果说明,由于土壤利用方式变化所导致的土壤理化性质改变对土壤无机碳和有机碳可能具有相反影响。在研究土壤碳平衡过程中,应该充分考虑这种关系所导致的相互补偿作用,即有机碳的增加,可能意味着无机碳的减少,或者反之。目前研究中普遍忽略无机碳的变化,可能导致生态系统碳收支计算显著偏差,所获得的经验拟合方程有利于对我国东北地区土壤碳平衡研究产生的这种偏差进行粗略估计。     

Co-metabolic degradation of pyrene by indigenous white-rot fungus Pseudotrametes gibbosa from the northeast China

Pyrene as high molecular weight polycyclic aromatic hydrocarbons (PAHs) is found in most terrestrial environment. However, the biodegradation of pyrene has been limited due to its bioavailability and toxicity. So it is vital to study degradation-capable microorganism and suitable co-substrate. In this study, the indigenous white-rot fungus Pseudotrametes gibbosa isolated from ChangBai Mountain located in northeast China was used to degrade pyrene, and 6 co-substrates were selected as co-metabolic carbon and energy sources. The results showed that P. gibbosa was able to utilize pyrene as sole carbon and energy source. The degradation efficiency achieved 28.33% within 18 days. Meanwhile, co-substrate wheat bran extract could stimulate laccase (Lac) production significantly by P. gibbosa, compared with other co-substrates and control (without co-substrate). In the presence of co-substrates, the biodegradation efficiency of pyrene ranged from 34.23% to 50.64% which was enhanced due to co-metabolism except for salicylic acid (25.91%) and phthalic acid (21.64%).     

龙桑一号桑叶精油的挥发性组分(英文)

桑品种龙桑一号(Morus alba)栽培于中国东北黑龙江省齐齐哈尔市甘南林场桑产业科技示范园。2009年7月、8月和9月的桑品种龙桑一号干桑叶精油中的挥发性组分经水蒸馏提取后进行了气相色谱-质谱(GC-MS)分析。结果表明桑叶精油的共有组分是植醇(醇类化合物)、六氢金合欢丙酮(酮类化合物)、二十七烷和二十五烷(烃类化合物)。棕榈酸为7月和8月采集桑品种龙桑一号干桑叶精油的共有第一主成分。顺式-β-金合欢烯、反式-β-金合欢烯、β-甜没药烯、反式-α-佛手柑油烯和α-姜黄烯是9月采集桑品种龙桑一号干桑叶精油的主要芳香组分。萜类化合物相对含量较高的9月份采集的干桑叶精油具有药用价值。     

蛹虫草原生质体紫外诱变选育胞外多糖高产菌株

蛹虫草是重要的药食兼用两用真菌,具有较高的医用及经济价值。本文通过单因素和正交试验的方法研究了不同酶系统、酶解温度、酶解时间、渗透压稳定剂、菌龄对蛹虫草原生质体形成的影响,并对蛹虫草原生质体进行紫外诱变,以生物量和胞外多糖产量为指标选育胞外多糖高产菌株。结果表明：在30℃、1％溶壁酶＋0．5％蜗牛酶＋0．5％纤维素酶条件下,以甘露醇为渗透压稳定剂对4日龄蛹虫草菌丝酶解2h,原生质体产量可达到9．2×10^6个/mL。从150株诱变株中筛选出1株最佳正诱变株,编号为44#,经深层培养其生物量比出发菌株提高10％,胞外多糖产量提高84．3％,继代培养10代后,遗传稳定性良好。     

小鼠胰腺大部分切除后再生集中区来源的初步探索

目的:探讨胰腺在某些损伤或病理条件下,由于细胞活跃增殖产生再生集中区域的细胞来源。方法:将27只成年ICR系小鼠分为9组,每组3只,其中1组进行假手术,其余8组进行小鼠胰腺大部分切除,分别在切除后12h,24h、36h、48h、3d、5d、7d、10d取材及冰冻切片,采用H-E染色、免疫荧光染色方法检测损伤后各时间段胰腺组织的形态变化和细胞增殖率。结果:H-E染色发现,胰腺手术72h后,剩余胰腺中就出现由细胞角蛋白阳性导管样结构组成的再生集中区,此区域细胞随后分化为功能性细胞类型,10d后消失检测不到。对胰腺再生集中区的定位研究表明,它们仅出现于切除后的伤口边缘。BrdU标记表明,胰腺再生集中区为细胞快速增殖区域,其出现与总导管增殖率提高同时发生,主/大导管和小导管增殖率上升都晚于再生集中区的出现。结论:小鼠胰腺大部分切除后再生集中区可能来源于腺泡细胞的快速增殖,而不是经由总-主/大-小导管-快速增殖区这一途径引起的来源于导管上皮细胞。