不同耕作措施对冬小麦-夏玉米复种连作系统土壤有机碳和水分利用效率的影响

在连续8年田间定位试验的基础上,分析了关中平原冬小麦 夏玉米复种连作系统2008—2009年连续两个生长季期间不同耕作措施(结合秸秆还田和不还田)对土壤有机碳和水分利用率的影响.结果表明: 相对于传统耕作,保护性耕作有利于土壤有机碳、水分利用效率和作物产量的提高,其中在“深松+秸秆还田”耕作模式下的增幅最高,土壤有机碳含量在0～30 cm土层增幅达到19.5%,水分利用效率和作物产量提高了16.9%和20.5%,而免耕模式则有效提高了0～10 cm土层有机碳含量.在该地区土壤和气候条件下,深松结合秸秆粉碎还田是最理想的耕作模式,最有利于土壤有机碳累积,并提高水分利用效率和作物产量.     

不同秸秆还田和耕作方式对夏玉米农田土壤呼吸及微生物活性的影响

采用基质诱导呼吸法和CO2释放量法,研究了冬小麦季长期不同耕作方式(常规翻耕、免耕和深松)和秸秆处理(秸秆还田和无秸秆还田)对夏玉米田土壤呼吸及微生物活性的影响.结果表明:秸秆还田和保护性耕作主要在O～ 10 cm土层起作用.秸秆还田能明显提高土壤微生物生物量碳和微生物活性,降低呼吸熵,在苗期和开花期提高土壤呼吸,而在灌浆期、腊熟期和收获期降低土壤呼吸;在相同秸秆处理条件下,深松和免耕比常规翻耕能显著降低土壤呼吸和呼吸熵,提高微生物生物量碳和微生物活性.整个生育期,秸秆还田结合保护性耕作能显著提高微生物生物量碳和微生物活性,降低呼吸熵,与常规翻耕无秸秆还田相比,深松秸秆还田和免耕秸秆还田0～10 cm土层微生物生物量碳平均提高了95.8％和74.3％,微生物活性提高了97.1％和74.2％.     

不同耕作方式对石灰性褐土磷脂脂肪酸及酶活性的影响

为探索不同耕作方式下土壤理化性状和微生物活性的变化,研究了秸秆还田下旋耕(RT)、深松(ST)、深翻(CT)和秸秆不还田旋耕(CK)4种耕作方式对石灰性褐土磷脂脂肪酸(PLFA)特性及水解酶活性的影响.结果表明:不同耕作处理的水解酶活性、养分含量及微生物群落多样性有较大差异;秸秆还田增加了PLFA的种类、总PLFA含量及细菌、放线菌PLFA含量,但降低了土壤真菌PLFA含量,说明真菌较细菌更能适应贫瘠的环境.深松和深翻处理的PLFA总量均高于旋耕和CK处理,两处理分别较CK处理高74.7%和53.3%,表明深松和深翻更有利于作物生长.深松和深翻还可改善土壤理化性状、提高土壤碱性磷酸酶、蛋白酶和脲酶活性,为作物高产稳产提供了有利的土壤条件.     

土壤耕作及秸秆还田对夏玉米田杂草生物多样性的影响

于2008年夏玉米(Zea mays)生长期间,在连续5a秸秆全量还田的免耕、旋耕、耙耕、深松和常规耕作试验地中,研究了杂草总密度、优势杂草种类、生物多样性指数、杂草生物量和夏玉米产量。调查共记录杂草种类13种,秸秆全量还田时,免耕显著提高杂草的总密度;无秸秆还田时,常规耕作的杂草密度高于免耕、旋耕、耙耕和深松。秸秆全量还田后,免耕和深松条件下,杂草优势种为马唐和旱稗,旋耕和耙耕条件下为马唐、旱稗和牛筋草;常规耕作条件下,优势杂草为马唐、苘麻、旱稗和香附子。无秸秆还田条件下,免耕和常规耕作增加了杂草优势种的数量。秸秆全量还田后,免耕、耙耕和深松等耕作措施导致杂草群落的物种丰富度及均匀度均较高。无论哪种耕作条件,5a连续秸秆还田能够显著提高夏玉米籽粒产量和生物学产量,其中尤以常规耕作秸秆全量还田处理产量最高,且田间杂草的生物学产量与夏玉米的生物学产量呈显著负相关关系。     

土壤有机碳和微生物群落结构对多年不同耕作方式与秸秆还田的响应

土壤有机碳对维持陆地生态系统功能和缓解土壤退化问题至关重要,土壤微生物参与土壤有机碳的循环过程,而耕作方式与秸秆还田影响土壤有机碳和微生物群落.本试验采用裂区试验设计,耕作方式为主区,分别设深松(ST)和旋耕(RT)处理,副区为秸秆还田量,分别设秸秆全还田(F)和秸秆不还田(0)处理,采用Illumina测序技术测定土壤微生物群落结构和固碳功能基因,并测定了2012—2017试验年间土壤有机碳含量.结果表明: 1)深松耕作和秸秆还田均显著提高了pH、微生物生物量碳、总氮、粉粒含量、黏粒含量,而显著降低了砂粒含量; 2)试验年间各处理的土壤有机碳(SOC)含量均呈增加趋势,但与旋耕耕作和秸秆不还田处理相比,深松耕作和秸秆还田处理的平均有机碳增量分别显著提高30.6%和33.2%; 3)土壤中最丰富的细菌类型为变形菌门,其次为酸杆菌门和芽单胞菌门; 4)深松秸秆还田处理(STF)具有较高的微生物多样性; 5)除砂粒含量外,土壤pH、微生物生物量碳、总氮、粉粒和黏粒含量均促使深松秸秆全还田处理下的微生物群落结构向着有利于有机碳积累的方向发生变异; 6)除二糖和寡糖代谢途径外,CO₂固定、发酵、主要碳水化合物代谢、一碳代谢、糖醇、有机酸、糖苷水解酶类的代谢功能基因丰度均表现为深松耕作显著高于旋耕,且均与土壤有机碳呈正相关关系.因此,深松结合秸秆还田能够改善土壤基本性质与土壤微生物群落结构,有利于增加土壤固碳能力和解决土壤退化问题.     

耕作方式对潮土土壤团聚体微生物群落结构的影响

为探究不同耕作方式对潮土土壤团聚体微生物群落结构和多样性的影响,采用磷脂脂肪酸(PLFA)法测定了土壤团聚体中微生物群落。试验设置4个耕作处理,分别为旋耕+秸秆还田(RT)、深耕+秸秆还田(DP)、深松+秸秆还田(SS)和免耕+秸秆还田(NT)。结果表明:与RT相比,DP处理显著提高了原状土壤和>5 mm粒级土壤团聚体中真菌PLFAs量和真菌/细菌,为真菌的繁殖提供了有利条件,有助于土壤有机质的贮存,提高了土壤生态系统的缓冲能力;提高了5～2 mm粒级土壤团聚体中细菌PLFAs量,降低了土壤革兰氏阳性菌/革兰氏阴性菌,改善了土壤营养状况;提高了<0.25 mm粒级土壤团聚体中微生物丰富度指数。总的来说,深耕+秸秆还田(DP)对土壤团聚体细菌和真菌生物量有一定的提高作用,并且在一定程度上改善了土壤团聚体微生物群落结构,有利于增加土壤固碳能力和保持土壤微生物多样性。冗余分析结果表明,土壤团聚体总PLFAs量、细菌、革兰氏阴性菌和放线菌PLFAs量与土壤有机碳相关性较强,革兰氏阳性菌PLFAs量与总氮相关性较强。各处理较大粒级土壤团聚体微生物群落主要受碳氮比、含水量、pH值和团聚体质量分数的影响,较小粒级土壤团聚体微生物群落则主要受土壤有机碳和总氮的影响。     

短期秸秆颗粒还田对小麦-玉米系统作物产量与土壤呼吸的影响

秸秆直接还田易造成土秸混合度差、秸秆腐解慢和幼苗群体质量差等问题,不利于作物稳产和增产.秸秆颗粒具有还田性能好、还田质量高的优点,但还田后对作物生长和土壤碳排放特征的影响仍不清楚.通过田间微区试验,以秸秆不还田和常规粉碎还田为对照,分析了秸秆颗粒还田对冬小麦和夏玉米籽粒产量、还田一年内土壤呼吸速率和土壤碳排放效率的影响,为改进秸秆还田方式提供理论依据.结果表明: 秸秆颗粒还田显著提高了冬小麦和夏玉米籽粒产量,其周年作物产量较秸秆不还田和常规粉碎还田分别显著提高14.0%和5.8%.秸秆颗粒还田促进土壤碳排放,其小麦生长季和玉米生长季土壤呼吸速率和碳累积排放量显著高于秸秆不还田.与常规粉碎还田相比,秸秆颗粒还田显著提高了冬小麦生长季土壤呼吸速率和碳累积排放量15.2%和8.9%,但夏玉米生长季两者无显著差异.此外,秸秆颗粒还田降低了土壤呼吸温度敏感指数(Q₁₀),提高了土壤碳排放效率.与秸秆不还田和常规粉碎还田相比,秸秆颗粒还田土壤呼吸敏感指数显著降低22.6%和10.1%,周年土壤碳排放效率提高2.3%和1.9%.可见,秸秆颗粒还田短期内显著促进土壤碳排放,但由于较高的作物产量,其碳排放效率能维持在较高水平.在黄淮海粮食主产区,秸秆颗粒还田可以作为一种新型的秸秆还田方式,但其土壤碳排放的长期效应仍需进一步研究.     

机械化保护性耕作条件下土壤质量的数值化评价

通过9年的长期田间定位试验研究了陕西关中平原中部冬小麦 夏玉米轮作条件下深松耕（ST）、旋耕（RT）、秸秆还（SR）、免耕（NTS）等保护性耕作措施及传统耕作（TT）对土壤理化性状和作物产量的影响,并采用主成分分析方法进行土壤质量的综合评价.结果表明：与传统耕作相比,保护性耕作模式提高了土壤肥力质量,改善了土壤物理环境条件;显著提高了土壤脲酶和碱性磷酸酶的活性;除秸秆覆盖免耕处理的玉米和小麦产量低于传统耕作外,其他保护性耕作措施均不同程度地提高了作物产量,其中小麦增产13%～28%,玉米增产3%～12%.与传统耕作相比,保护性耕作土壤质量指数提高了19.8%～44.0%.综合考虑经济效应和生态效益,隔年深松、秸秆粉碎联合旋耕作业以及秸秆覆盖联合深松作业不仅能增加作物产量还可改善土壤质量,可在研究区进行推广应用.     

不同耕作方式和秸秆还田对麦田土壤有机碳含量的影响

通过两个生长季试验,研究了不同耕作方式和秸秆还田及其交互效应对小麦全生育期0～20 cm土壤有机碳含量的影响.结果表明：小麦不同生育时期0～20 cm土层有机碳含量呈明显的动态变化;秸秆还田各处理的有机碳含量都高于无秸秆还田处理;保护性耕作措施土壤有机碳增加量显著高于传统翻耕.除传统翻耕处理外,各处理0～10 cm土层的有机碳含量都高于10～20 cm土层,秸秆还田各处理0～10 cm土层有机碳含量表现为深松(PS)＞旋耕(PR)＞免耕(PZ)＞耙耕(PH)＞传统翻耕(PC),而10～20 cm土层表现为传统翻耕(PC)＞深松(PS)＞旋耕(PR)＞耙耕(PH)＞免耕(PZ),说明保护性耕作措施能提高0～10 cm土层的有机碳含量.多因素方差分析表明：耕作因素、秸秆因素和两者交互效应在不同生育期对0～20 cm土层的有机碳含量都有显著影响.     

不同水稻栽培模式下小麦秸秆腐解特征及对土壤生物学特性和养分状况的影响

采用尼龙网袋法于2007-2008年连续2a在水稻常规栽培和节水灌溉栽培模式下,研究小麦秸秆腐解特征、养分释放规律及对土壤微生物数量、酶活性和养分状况的影响.结果表明:秸秆还田后,在0-30d腐解较快,后期腐解速率逐渐变慢.90d时累计腐解率达到了48.9％-61.3％.秸秆中养分释放速率表现为K＞P＞N≈C.节水栽培模式下小麦秸秆还田腐解率和养分释放率均显著高于常规栽培.秸秆还田后,土壤微生物数量以及土壤脲酶、碱性磷酸酶和蔗糖酶活性均呈现“前期迅速增加,中期急剧减少,后期缓慢减少”的变化特征,而纤维素酶活性呈现“前期剧升、中期缓增、后期骤降”的变化趋势.小麦秸秆在节水栽培模式下还田土壤微生物数量和酶活性均显著高于常规栽培.适当增加秸秆用量可以提高微生物数量和酶活性,用量过高对细菌和放线菌数量有负效应.秸秆还田可显著提高土壤有机碳和养分含量.土壤有机碳、全氮、碱解氮和速效磷含量在整个试验期间均呈增加趋势.速效钾含量在秸秆还田30 d时达到最高,而后则逐渐降低.节水栽培模式下秸秆还田后土壤有机碳和养分含量的提高效应显著高于常规栽培.提高秸秆用量对土壤养分含量有显著的正效应.     

New amino-dithiaphospholanes and phosphoramidodithioites and their rhodium and iridium complexes

New sulfur derivatives of phosphoramidite ligands were synthesized and the impact of the sulfur unit on the spectroscopic properties of their rhodium and iridium complexes was investigated. The new ligands Bn₂NPSCH₂CH₂S^a(P-S^a) (Bn = benzyl, 4), Bn₂NPSCHCHS^a(CH₂)₃C^aH₂(P-S^a)(C^a-S^a) (6) and Bn₂NP(4-XC₆H₄OMe)₂ (X = S, 7a; X = O, 7b) were converted to the rhodium and iridium complexes trans-[Rh(CO)Cl(L)₂] (L = 4, 6, 7), [RhCl(COD)(L)] (L = 4, 6, 7), [IrCl(COD)(7a)] and [IrCl₂Cp∗(6)]. For comparison, some phosphoramidite complexes of these formulations also were synthesized. The new metal complexes were spectroscopically analyzed. For the carbonyl complexes, the ν_CO IR stretching frequencies were lower than for the corresponding phosphite and phosphoramidite ligands. The ¹J_PRh coupling constants for the rhodium complexes with the new ligands were also smaller than for the respective phosphoramidite and phosphite complexes. Finally, the ¹J_PSe coupling constants of the selenides of the new ligands were lower than those of the phosphoramidite ligands but higher than for PPh₃. The spectroscopic data reveal that the new thio ligands 4, 6 and 7a are more electron donating than phosphites and phosphoramidites but less electron donating than PPh₃.     

Astrocytes and Synaptosomes Transport and Metabolize Lactate and Acetate Differently

Astrocytes transport the monocarboxylate acetate, but synaptosomes do not. The reason for this is unknown, because both preparations express monocarboxylate transporters (MCT). The transport and metabolism of lactate, another monocarboxylate, was examined in these two preparations, and the results were compared to those for acetate. Lactate transport is more rapid in astrocytes than in synaptosomes, but of lower affinity (Kms of 17 and 4 mM, respectively). Lactate (0.2 mM) is metabolized to CO2 more rapidly in synaptosomes than in astrocytes (rates of 0.37 and 0.07 nmol x mg protein(-1) x min(-1), respectively). The reason for this is unclear, but cellular differences in lactate dehydrogenase isotype expression may be involved. Acetate is metabolized to CO2 more rapidly in astrocytes than in synaptosomes (rates of 0.43 and 0.02 nmol x mg protein(-1) x min(-1), respectively). This is likely due to cellular differences in the expression of monocarboxylate transporter subtypes.     

白蚁与动物及微生物的共生类型及其机制

综述了白蚁螱客的主要种类、共生关系及相关机制的研究进展。白蚁螱客中,已报道的动物种类达170种。在与动物的共生关系中存在偏利共生（宾主共栖和异种共栖）、互利共生和无关共生三种;在与微生物的共生关系中,存在与内生菌（原生动物、细菌、真菌和放线菌）和外生菌（蚁巢伞菌等）间的互利关系。指出了白蚁与螱客研究中存在的问题,给出了解决方案,并提出了今后可能的研究热点或方向,为白蚁的综合利用（如纤维素酶）及今后研究物种间的协同进化提供了基础资料。     

Rapporteur report: Basics and technology and metrology and standards

The first and second sessions of the Workshop focussed on the basics of ultrasound and infrasound, their applications in both industry and medicine, and metrology and protection standards for ultrasound applications.     

Relative and combined effects of ethanol and protein deficiency on strontium and barium bone content and fecal and urinary excretion

To elucidate accumulation of minerals in human iliac arteries with aging, the content of minerals was analyzed by inductively coupled plasma atomic emission spectrometry. Bilateral common, internal, and external iliac arteries of 16 men and 8 women, ranging ages from 65 to 93 yr, were examined. It was found that an extremely high accumulation of calcium and phosphorus occurred in the common iliac artery at old age, being higher than that of the internal and external iliac arteries. It should be noted that the accumulation of calcium and phosphorus is the highest in the common iliac artery among the human arteries examined to date. Regarding sexual differences, the content of calcium and phosphorus in the common and internal iliac arteries was higher in women than in men, whereas their content in the external iliac artery was lower in women than in men.     

人血管能抑素基因的克隆、表达及其表达产物的纯化和生物活性测定

以人胎盘脐带组织为材料,提取组织总RNA,用netRTPCR方法合成人血管能抑素cDNA基因,将该cDNA克隆进pSP72载体获得重组质粒pSP72C, DNA序列分析结果与预期序列一致。用BamHⅠ和NdeⅠ双酶切,切下pSP72C上的血管能抑素cDNA,插入pET3c载体的相应位点获得重组表达质粒pETC, 转化E. coli BL21(DE3), SDSPAGE分析显示：在IPTG诱导下,血管能抑素基因获得了高效表达,表达量约占菌体总蛋白的 27.9 %,主要以包涵体形式存在。包涵体经过洗涤、裂解、蛋白复性以及Sephadex G75凝胶过滤层析等步骤后,获得了纯度达91.4 %的人血管能抑素。CAM实验证明10 μg纯化蛋白就能显著抑制鸡胚新生血管生成。     

Cytoskeleton and mitochondrial morphology and function

It has been well established that the cytoskeleton is an essential modulator of cell morphology and motility, intracytoplasmic transport and mitosis, however cytoskeletal linkage to the organelles has not been unequivocally demonstrated. Indeed, cytoskeleton appears to be essential in determining and modulating gene phenotype as a function of cellular environment. According to recent studies, the organization of the cytoskeleton network together with associated protein(s) could be essential in regulating mitochondrial function and particularly the permeability of the mitochondrial outer membrane to ADP. The aim of this chapter is to summarize the main properties of the cytoskeletal environment of mitochondria and the possible role(s) of this network in mitochondrial function in myocytes.     

Vascular volumes and hematology in male and female runners and cyclists

To examine the hypothesis that foot-strike hemolysis alters vascular volumes and selected hematological properties is trained athletes, we have measured total blood volume (TBV), red cell volume (RCV) and plasma volume (PV) in cyclists (n = 21) and runners (n = 17) and compared them to those of untrained controls (n = 20). TBV (ml x kg(-1)) was calculated as the sum of RCV (ml x kg(-1)) and PV (ml x kg(-1)) obtained using 51Cr and 125I-labelled albumin, respectively. Hematological assessment was carried out using a Coulter counter. Peak aerobic power (VO2peak) was measured during progressive exercise to fatigue using both cycle and treadmill ergometry. RCV was 15% higher (P < 0.05) in male cyclists [35.4 (1.0), mean (SE); n = 12] and runners [35.3 (0.98); n = 9] compared to the controls [30.7 (0.92); n = 12]. Similar differences existed between the female cyclists [28.2 (2.1); n = 9] and runners [28.4 (1.0); n = 8] compared to the untrained controls [24.9 (1.4); n = 8]. For the male athletes, PV was between 19% (cyclists) and 28% (runners) higher (P < 0.05) in the trained athletes compared to the untrained controls. The differences in PV between the female groups were not significant. Although the males had a higher (P < 0.05) TBV, RCV and PV than the females, no differences between cyclists and runners were found for either gender. Mean cell volume was not different between the athletic groups. VO2peak (ml x kg(-1) x min(-1)) was higher (P < 0.05) in both male [68.4 (1.5)] and female [54.8 (2.1)] runners when compared to the untrained males [47.1 (1.0)] and females [40.5 (2.1)]. Although differences existed between the genders in VO2peak for both cyclists and runners, no differences were found between the athletic groups within a gender. Since the vascular volumes were not different between cyclists and runners for either the males or females, foot-strike hemolysis would not appear to have an effect on that parameter. The significant correlations (P < 0.05) found between VO2peak and RCV (r = 0.64 and 0.64) and TBV (r = 0.82 and 0.63) for the males and females, respectively, suggests a role for the vascular system in realizing a high aerobic power.     

Microbial and bioconversion production of D-xylitol and its detection and application

D-Xylitol is found in low content as a natural constituent of many fruits and vegetables. It is a five-carbon sugar polyol and has been used as a food additive and sweetening agent to replace sucrose, especially for non-insulin dependent diabetics. It has multiple beneficial health effects, such as the prevention of dental caries, and acute otitis media. In industry, it has been produced by chemical reduction of D-xylose mainly from photosynthetic biomass hydrolysates. As an alternative method of chemical reduction, biosynthesis of D-xylitol has been focused on the metabolically engineered Saccharomyces cerevisiae and Candida strains. In order to detect D-xylitol in the production processes, several detection methods have been established, such as gas chromatography (GC)-based methods, high performance liquid chromatography (HPLC)-based methods, LC-MS methods, and capillary electrophoresis methods (CE). The advantages and disadvantages of these methods are compared in this review.