花椒叶和土壤浸提液对土壤微生物、土壤酶及土壤化学性质的影响

花椒（Zanthoxylum bungeanum Maxim.）是川西地区重要的经济植物，化感作用是花椒连作障碍的原因之一，而花椒凋落物和根系分泌物对土壤质量的影响是花椒化感作用的一个重要方面。系统研究花椒如何影响土壤有助于深入理解和解决花椒连作障碍。本文主要以大红袍（10a生）花椒叶和种植过花椒的土壤的浸提液浇灌花椒幼苗进行试验，分析叶浸提液与土壤浸提液对非花椒生长土壤中土壤微生物、土壤酶及土壤化学性质的影响。主要结果如下： 1.花椒叶浸提液和土壤浸提液减少了土壤中微生物的种类、组成和数量。本试验中未施加浸提液的土样中根际微生物明显高于非根际区，在经过花椒叶浸提液处理后，根际细菌、真菌和放线菌数量以及微生物总数都有所减少，这样将会导致土壤中的有效养分的供给减少，进而可能影响植物的生长。 2．施加花椒叶浸提液和土壤浸提液，以及花椒幼苗的栽种，对不同土样中的土壤酶各有促进和抑制作用。在浸提液处理下，水解酶之间及氧化还原酶之间各存在相互促进作用。 3.施加花椒叶浸提液和土壤浸提液均抑制了根际土中全氮和有机质含量，叶浸提液还抑制了无苗土中全磷含量，土壤浸提液还抑制了无苗土中全氮含量与根际土全磷、有机质含量。但两种浸提液均促进了根际土中有效磷和水解性氮含量、根外土中全磷含量，叶浸提液促进了根际土中全磷含量，土壤浸提液促进了根外土中有效磷含量。全氮和有机质含量的下降可能对植物生长发育不利。 4．土壤化学性质与土壤酶活性在不同土样中有不同的相关性。全氮含量在施加叶浸提液的土样中与蛋白酶活性呈正相关。水解性氮含量在施加叶浸提液的土样中与蛋白酶活性、蔗糖酶活性呈正相关。全磷含量在施加叶浸提液的土样中与多酚氧化酶活性呈正相关；在施加土壤浸提液的土样中与蛋白酶活性、蔗糖酶活性呈正相关，与多酚氧化酶活性呈负相关。有效磷含量在施加叶浸提液的土样中与多酚氧化酶活性呈正相关，与蛋白酶活性呈负相关；在施加土壤浸提液的土样中与蛋白酶活性、过氧化氢酶活性呈正相关。有机质含量在施加叶浸提液的土样中与蛋白酶活性、蔗糖酶活性呈正相关。 Zanthoxylum bungeanum is one of the most important cash crops in Eastern Tibetan Plateau. Allelopathic effects could be one of reasons for Z. bungeanum’s continuous cropping impediment. The effects of secretion of leaf and root of Z. bungeanum on soil quality is a important way of Z. bungeanum’s allelopathic effects. However, allelopathic effect of Z.bungeanum on soil microbes, enzyme activities and chemical property were seldom studied. In this study, leaf and soil extracts of Da Hongpao(DHP), the most common varieties of Z.bungeanum in this area, were used to assess allelopathic effect of Z. bungeanum on soil biology and biochemistry by pot experiments . The main results showed that: 1. The irrigation of two kinds of extracts reduced the species, component and quantity of soil microbes. In rhizosphere soil which irrigated by distilled water, the quantity of soil microbes is significantly different from exoroot soil. In rhizosphere soil which irrigated by leaf extracts, the quantity of bacterial, fungi, actionmycete and gross of microbes were decreased, it may resulted in reduce of Available nutrient in soil, and influenced the growth of plants. 2．The irrigation of two kind of extracts reduced or enhanced the enzyme activities in different soils. Interaction between hydrolytic ferments and redoxases were promoted each other. 3. The irrigation of two kinds of extracts reduced the total N and organic matter in rhizosphere soil. Leaf extracts also reduced the total P in soil without seedling. Soil extracts reduced total N in soil without seedling and total P, organic matter in rhizosphere soil. But both extracts also enhanced available P and hydrolysable N in rhizosphere soil, total P in exoroot soil. Leaf extracts enhanced total P in rhizosphere soil. Soil extracts enhanced available P in exoroot soil. The reduction of total N and organic matter may influence growth of plants. 4．Positive correlations between total N and prolease, hydrolysable N and prolease, hydrolysable N and saccharase, total P and polyphenol oxidase, available P and polyphenoloxidase, organic matter and prolease, organic matter and saccharase, were studied in soil irrigated by leaf extracts. In soil irrigated by soil extracts, there are positive correlations between total P and prolease, total P and saccharase, available P and prolease, available P and catalase, while negative correlation between total P and polyphenoloxidase, available P and prolease, available P and catalase was found.

Outline of the progress in the study of radioactive nuclear physics and super-heavy nuclei

We briefly introduce the current status and progress in the field of radioactive ion beam physics and the study of super-heavy nuclei. Some important problems and research directions are outlined, such as the sub-barrier fusion reaction, the direct reaction at Fermi energy and high energies, the property of nuclei at drip-lines, new magic numbers and new collective motion modes for unstable nuclei and the synthesis and study of the super-heavy nuclei.

Construction and test of Wien-filter combined with RIBLL

A recoil separator Wien-filter which was developed for the Radioactive Ion Beam Line in Lanzhou (RIBLL) as an extension is described. It consists of 2 quadruple triplets and a standard Wien-filter. It was designed for study of the fusion-evaporation reactions. The overall design, background suppression, the transmission efficiency, the angular acceptance and the momentum acceptance have been described. All the performances fulfil the designed requirements. Based on the test results, with some modifications the investigations of the nuclei with Z <= 110 and the drip-line nuclei in the medium-heavy mass region can be carried out with this facility.

Improved BCS-type pairing for the relativistic mean-field theory

A density-dependent delta interaction (DDDI) is proposed in the formalism of BCS-type pairing correlations for exotic nuclei whose Fermi surfaces are close to the threshold of the unbound state. It provides the possibility to pick up those states whose wave functions are concentrated in the nuclear region by making the pairing matrix elements state dependent. On this basis, the energy level distributions, occupations, and ground-state properties are self-consistently studied in the RMF theory with deformation. Calculations are performed for the Sr isotopic chain. A good description of the total energy per nucleon, deformations, two-neutron separation energies and isotope shift from the proton drip line to the neutron drip line is found. Especially, by comparing the single-particle structure from the DDDI pairing interaction with that from the constant pairing interaction for a very neutron-rich nucleus it is demonstrated that the DDDI pairing method improves the treatment of the pairing in the continuum.

beta-delayed proton decays and spin assignments for Sm-133 and Yb-149

The proton-rich isotope Sm-133 was produced via the fusion evaporation reaction Ca-40 + Ru-96. Its beta-delayed proton decay was studied by p-gamma coincidence in combination with a He-jet tape transport system, and half-lives, proton energy spectra, gamma-transitions following the proton emission, as well as beta-delayed proton branching ratios to the low-lying states in the grand-daughter nucleus were determined. Comparing the observed beta-delayed proton branching ratios with statistical model calculations, the best agreement is found assuming that only one level with the spin of 3/2 in Sm-133 decays or two levels with the spins of 1/2 and 5/2 decay with similar half-lives. The configuration-constrained nuclear potential energy surfaces of Sm-133 were calculated using the Woods-Saxon-Strutinsky method, which suggests a 1/2-ground state and a 5/2(+) isomer with an excitation energy of 120 keV. Therefore, the simple(EC+beta(+)) decay scheme of Sm-133 in Eur. Phys. J.A 11,277(2001) has been revised. In addition, our previous experimental data on the beta-delayed proton decay of Yb-149 reported in Eur. Phys. J. A 12,1 ( 2 0 0 1) was also analyzed using the same method. The spin-parity of Yb-149 is suggested to be 1/2(-).

Systematic study of properties of Hs nuclei

The ground-state properties of Hs nuclei are studied in the framework of the relativistic meanfield theory. We find that the more relatively stable isotopes are located on the proton abundant side of the isotopic chain. The last stable nucleus near the proton drip line is probably the (255)Hs nucleus. The alpha-decay half-lives of Hs nuclei are predicted, and together with the evaluation of the spontaneous-fission half-lives it is shown that the nuclei, which are possibly stable against spontaneous fission are (263-274)Hs. This is in coincidence with the larger binding energies per nucleon. If (271-274)Hs can be synthesized and identified, only those nuclei from the upper Z = 118 isotopic chain, which are lighter than the nucleus (294)118, and those nuclei in the corresponding alpha-decay chain lead to Hs nuclei. The most stable unknown Hs nucleus is (268)Hs. The density-dependent delta interaction pairing is used to improve the BCS pairing correction, which results in more reasonable single-particle energy level distributions and nucleon occupation probabilities. It is shown that the properties of nuclei in the superheavy region can be described with this interaction.

A high performance Time-of-Flight detector applied to isochronous mass measurement at CSRe

A high performance Time-of-Flight detector has been designed and constructed for isochronous mass spectrometry at the experimental Cooler Storage Ring (CSRe) The detector has been successfully used in an experiment to measure the masses of the N approximate to Z approximate to 33 nuclides near the proton drip-line Of particular interest is the mass of As-65 A maximum detection efficiency of 70% and a time resolution of 118 +/- 8 Ps (FWHM) have been achieved in the experiment The dependence of detection efficiency and signal average pulse height (APH) on atomic number Z has been studied The potential of APH for Z identification has been discussed (C) 2010 Elsevier B V All rights reserved

Effects of Pairing Correlations on Formation of Proton Halo in C-9

Properties for the ground state of C-9 are studied in the relativistic continuum Hartree-Bogoliubov theory with the NLSH, NLLN and TM2 effective interactions. Pairing correlations are taken into account by a density-dependent delta-force with the pairing strength for protons determined by fitting either to the experimental binding energy or to the odd-even mass difference from the five-point formula. The effects of pairing correlations on the formation of proton halo in the ground state of C-9 are examined. The halo structure is shown to be formed by the partially occupied valence proton levels p(3/2) and p(1/2).

轻核区质子滴线附近奇异核#beta#延迟质子衰变研究

远离#beta#稳定线的原子核所具有的特性是否与稳定区附近的核的性质相同，一直是核物理学家所关注的问题，实验上通过对缺中子区奇异核#beta#~+延迟粒子衰变的研究，可以精确测定与核性质有关的各个参数，这将对核结构理论研究产生重要的影响。本论文将首先介绍奇异核#beta#~+延迟粒子衰变研究的历史及其理论，接着介绍关于此研究的实验技术，最后详尽阐述对~(19)Na、~(65)Se和~(20)Na的研究

土壤水分特征曲线在作物非充分灌溉适宜水分下限确定中的应用

SPAC系统中水总是从水势高处流向水势低处,土壤水势的高低是影响植物根系吸水速率的主要因素。相对于土壤含水量来说,用土壤水势作作物非充分灌溉的下限指标更具科学性,更利于水分下限指标的推广应用。试验结果表明,对于整个生育期来说,-200 kPa是比较适宜的大棚番茄土壤水势下限。在这一指标的推广过程中,须先测定当地土壤水分特征曲线,并从曲线上找出该适宜水势对应的土壤含水量,通过控制土壤含水量达到控制土壤水势的目的,从而实现精量灌溉。

陕北山地红枣集雨微灌技术集成与示范

陕北山地红枣集雨微灌技术综合集成了坡地降雨径流调控技术、山地红枣矮化密植栽培技术及修剪技术,在对微灌技术进行创新的基础上,形成了黄土高原山地红枣微灌技术体系,并在黄土高原丘陵沟壑区第一附区——陕西省榆林市米脂县创建了技术体系应用实体样板,该样板地红枣平均产量达到19 800 kg/hm2,较无灌溉条件(产量4 500~6 000 kg/hm2)增产2~3倍,较管灌条件(产量一般为12 000~15 000 kg/hm2)增产30%~60%,且节水36%以上。在单项技术研究方面,利用Penman-Monteith公式确定了红枣生育期理论耗水量(438.8mm);通过不同灌水量处理的田间试验,初步确定出合理的灌水量区间为396~1 320 m3/hm2;提出了坡地低压滴灌工程新的设计理论,即微地形影响下的均匀度计算方法、滴头设计工作压力取值理论及毛管设计新方法;在此基础上,提出了坡上部采用三项配套技术+低压滴灌、坡下部采用三项配套技术+涌泉根灌+雾喷的工程模式。

变水处理与短期遮荫对作物水分利用效率的影响

变水处理与短期遮荫对棉花水分利用效率的影响研究表明 ,在充分供水 -水分胁迫 -复水的变水处理过程中 ,短期遮荫使净光合速率、蒸腾速率、水分利用效率降低 ;光照 -遮荫 -光照期间 ,总的水分利用效率以水分胁迫的最高 ,充分供水的次之 ,复水处理最低 ,其中遮荫 40 %的水分利用效率高于遮荫 75%的处理 .回归分析表明 ,水分利用效率与光合速率表现出极显著正相关 ,两者回归直线的斜率随水分胁迫而增大 ,而水分利用效率与蒸腾速率的关系较弱 ,多数处理两者相关达不到显著水平

陕北丘陵沟壑区经济林果发展战略

陕北丘陵沟壑区经济林果发展 ,必须抓好建设规划 ,加强坡地经济林果的集流节水保墒和科技宣传 ,创建自己的市场 ,才能解决好植被建设和经济发展这个问题