农田土壤动物和微生物与生物化学动态关系的研究

研究了农田土壤动物和微生物的季节动态与土壤生物化学特征之间的关系 ,并利用灰色理论与方法进行分析。结果表明 ,土壤生物和土壤生物化学特征均有明显的季节性变化。而土壤动物和微生物的季节动态与土壤生物化学特征之间也具有明显的相关性。其中关系最大的生物化学特征是过氧化氢酶、脱氢酶、无机磷转化作用和枯枝落叶分解速率。并建立了 5个灰色数学模型 [GM(1,5 ) ]。     

拟鹅观草属6种2亚种和鹅观草属3种植物的核型研究

对拟鹅观草属Pseudoroegneria 6种2亚种和鹅观草属Roegneria 3种植物的核型进行了研究,核型公式如下：P. spicata (Pursh) A. Lve,2n=2x=14=12m (2sat)+2sm; P. strigosa ssp. aegilopoides (Drobov) A. Lve,2n=2x=14=12m (2sat)+2sm; P. libanotica (Hackel) A. Lve,2n=2x=14=10m+4sm (4sat); P. stipifolia     

农田土壤枯枝落叶分解代谢的灰色分析

研究了农田土壤枯枝落叶分解代谢过程的影响因素。结果表明 ,农田土壤枯枝落叶分解速率有明显的季节变化 ;分解速率的高峰值主要是在 7,8月份。通过灰色关联分析表明 ,影响土壤枯枝落叶分解速率的主要因素是弹尾类动物、线虫类动物、无机磷转化作用和土壤含水量。建立了灰色数学模型     

土壤和叶面Pb污染对小麦生长及体内Pb分布和积累的影响

通过土壤添加Pb和叶面喷施Pb溶液的方式研究了Pb污染对小麦(Triticum aestivum L. )地上部分和籽粒干质量的影响,并对Pb污染条件下小麦体内Pb的分布和积累规律以及Pb污染浓度与籽粒Pb含量的相关性、叶片Pb含量与籽粒Pb含量的相关性进行了分析.结果表明:土壤中Pb添加量为2 000 mg·kg-1时,小麦地上部分和籽粒的干质量分别较对照下降了15.5%和13.3%,差异显著(P<0.05);叶面喷施100 mg·L-1Pb溶液,小麦地上部分和籽粒干质量分别较对照下降了10.3%和15.5%,差异显著(P<0.05).在土壤和叶面Pb污染条件下,小麦各器官的Pb含量均随Pb污染浓度的提高而增大;在土壤Pb污染条件下,小麦根中的Pb含量远高于其他器官,籽粒中的Pb含量最低;在叶面Pb污染条件下,小麦叶片中的Pb含量远高于其他器官,籽粒和根中的Pb含量较低.回归分析结果表明,小麦籽粒中的Pb含量与Pb污染浓度呈极显著正相关(P<0.001),籽粒中的Pb含量与土壤Pb总含量和叶面Pb污染浓度的曲线方程分别为: y＝0.269+0.001 05x+2.736×10-7x2-1.707×10-10x3和y＝0.465+0.013x-1.1×10-5x2+3.96×10-9x3;土壤中总的Pb毒性临界值为209.3 mg·kg-1,叶面Pb的毒性临界值为2.6 mg·L-1;在土壤和叶面Pb污染条件下,小麦籽粒中的Pb含量与叶片Pb含量间呈极显著的正相关(P<0.01),回归方程分别为:y=0.120 1x+0.076和y=0.001 6x+ 0.601 1,据此,在土壤和大气Pb污染条件下,可通过测定小麦叶片的Pb含量预测小麦籽粒中的Pb含量.     

种群模型参数辨识的一种方法

1、M(。,m)模型的建立定理.对于微分方程 dnx,(t)dtn+口zd卜lx,(t) dtn一1+…+a。_:dx:(t) dt否,x,(‘)+box:(‘)+b3x;(‘)x:(‘)+…+”。·,x:(‘)‘二(‘)给定样本数据{x;(k)1,k二1,2,…,N,i=I,2,…,m,则该方程的参数向量a=〔a:aZ…a。一,ib:bZ…b二+:〕丁可通过〔(AIB)T(A{B)〕一’(A{B)TC辨识,其中,C=〔△,x;(2),△nx:(了),…,△。x,(N)〕T陈华豪等万卷s2/△,一‘x工(2)△“一‘x:(3)…△x:(2)△x:(3)A二一……△一’x,(N),△x,(、){,111\x,(z),x贯(1),x,(1)x:(1),…,x;(了).x二(I)B二‘1‘“’,‘飞‘”,‘1.:员.,‘2‘2’,”…     

害虫,天敌和食料的数学模型

本文从实际问题出发,结合已有的描述群落生态的数学模型,提出了一组描述马尾松毛虫(Dendrolimus pnnctalus,walker)、条毒蛾(Lymantria dissoluta,Swinhoe)、天敌和食料之间动态关系的数学模型: w(k+1=(a_1x(k+1)/(1+a_2x(k+1)/_z(k))+a_3w(k)/(1+a_4w(k)/y(k)) x(k+1)=b_1w(k)/(1+b_2w(k)/y(k))+b_3x(k)/(1+b_4x(k)/z(k))+ y(k+1)=c_1z(k)/[1+c_sz(k)+c_3y(k)][1+c_4w(k)+(k+1)] z(k+1)=d_1z(k)/[1+d_2z(k)][1+d_3x(k)+d_4w(k)] 对于这个模型的线性化形式,详细讨论了控制松毛虫的暴发所需的条件及其生态学机制。     

东北松嫩平原羊草群落的土壤呼吸与枯枝落叶分解释放CO2贡献量

根据静态气室法的测量结果 ,分析了羊草群落土壤呼吸量和枯枝落叶分解释放 CO2 量的季节动态 ,及其与地上生物量 ,枯枝落叶分解量及环境因子的关系。结果表明 :( 1 )在整个观测期内 ,羊草群落土壤呼吸的季节动态呈现单峰曲线 ,8月中旬达到最大值 1 3.2 7g C/( m2 · d)。 ( 2 )羊草群落土壤呼吸的季节变化规律与地上绿色体生物量的季节动态同步。( 3)羊草群落土壤呼吸的季节动态与枯枝落叶分解量的季节动态同步。 ( 4 )羊草群落土壤呼吸量与土壤 0～ 1 0 cm土壤含水量显著正相关。( 5 )地表枯枝落叶层直接排放 CO2 量的季节动态呈现逐渐递减的趋势 ,释放量平均为 -0 .87g C/( m2·d)。有减缓土壤向大气排放 CO2 的作用。 ( 6 )枯枝落叶分解释放 CO2 量同地表枯枝落叶量显著正相关。     

武汉地区野豌豆属3种植物的染色体研究

本文报道了武汉地区野豌豆属3种植物的染色体数目及核型,结果如下:窄叶野豌豆为2n=2x=12=2sm+2st(SAT)+8st;小巢菜为2n=2x=14=10m+2sm(SAT)+2st;四籽野豌豆为2n=2x=14=4m+2sm(SAT)+8sm。本文还对野豌豆属染色体进化的有关问题进行了讨论。     

美国南卡罗来纳州森林湿地十种典型植物凋落叶的分解特征

凋落叶分解是控制森林湿地物质循环的重要生态过程,是全球C、N等元素循环的重要一部分。以美国南卡罗来纳州10种典型植物的凋落叶为研究对象,通过2a的分解实验测定分解阶段凋落叶的生物量残留率、分解速率常数k和C、N残留百分比,探讨初始凋落叶化学性质对分解速率常数k的影响。结果表明:(1)十种凋落叶生物量在两年内降解至初始的14.5%—66.2%,种间差异可达4倍以上;分解速率常数k在0.26—1.64a~(-1)之间,针叶分解速率阔叶分解速率;(2)分解速率常数k与初始凋落叶酸溶性组分(AS)极显著正相关(P0.001),与初始C含量、酸不溶组分(AIF)和AIF/N比均显著负相关(P0.05);(3)凋落叶C残留百分比持续下降至10.2%—66.1%,而N残留百分比因物种与分解阶段不同呈现不同变化规律。结果表明,森林湿地中凋落叶初始C组分差异是其分解速率的种间极大差异的主要原因,评估森林湿地的C、N循环应充分考虑种间差异。     

黄土高原樟子松和落叶松与其他树种枯落叶混合分解对土壤的影响

通过采集树木枯落叶与土壤进行室内混合分解培养试验,研究了黄土高原常见的樟子松和落叶松与其他树种枯落叶混合分解对土壤性质的影响及存在的相互作用,从而为不同树木种间关系的探索和该地区人工纯林的混交改造提供科学指导。结果表明:12种枯落叶单一分解均明显提高了土壤脲酶(54%—110%)、脱氢酶(85%—288%)和磷酸酶(81%—301%)活性以及有机质(29%—55%)和碱解N(12%—49%)含量,但对土壤速效P含量和CEC的影响存在较大差异。综合而言,樟子松分别与白桦、刺槐、白榆、柠条和落叶松枯落叶混合分解在对土壤性质的影响中存在相互促进作用,而分别与小叶杨、沙棘、紫穗槐、侧柏和辽东栎枯落叶混合分解在对土壤性质的影响中存在相互抑制作用;落叶松分别与刺槐、白桦、小叶杨和紫穗槐枯落叶混合分解在对土壤性质的影响中存在相互促进作用,而分别与柠条、侧柏、辽东栎、沙棘、油松和白榆枯落叶混合分解在对土壤性质的影响中存在相互抑制作用。     

Carbon isotopes and carbon turnover in cotton and wheat FACE experiments

The Maricopa cotton and wheat FACE (free-air CO₂ enrichment) experiments offer propitious opportunity to quantify carbon turnover. The commercial CO₂ (% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqiTdq2aaW% baaSqabeaacaaIXaGaaG4maaaakiaaboeacqGHijYUcqGHsislcaaI% ZaGaaG4naiaacwcaliaad+gaaaa!3FCB!\[\delta ^{13} {\text{C}} \approx - 37\% o\]) used to elevate CO₂ concentration in field plots provided a strongly ¹³C-depleted tracer. Soil CO₂ and ¹³C of soil organic carbon (SOC) in CO₂-enriched and Control plots were measured between the final cotton FACE project (October 1991) and the end of the second wheat experiment (June 1994). The initial ¹³C-depletion in SOC of cotton FACE plots (measured by the difference in ¹³C between FACE and Control plots) persisted at the same level (1.9) 1.5 years after the experiment ended. A similar depletion was observed in soil CO₂ evolved in the same plots, indicating ongoing decomposition of the new SOC. The SOC ¹³C of wheat plots before and after two growing seasons showed increasing ¹³C-depletion in FACE relative to Control. Isotopic mass balance was consistent with 5–6% new carbon input from the two wheat crops. This is lower than the 12–13% calculated for FACE cotton and perhaps a consequence of the larger root system of cotton or the 3-year duration of the cotton experiments versus 2 years for the wheat.     

华北平原麦田土壤呼吸特征

采用静态箱／气相色谱(GC)法测定了华北平原典型冬小麦田的土壤呼吸速率、结果表明,土壤呼吸速率日变化呈单峰曲线,最高峰出现在13：00左右,最低点在凌晨4：00左右;冬小麦生长季土壤呼吸速率平均冬季较低,夏季较高,与地温的季节变化趋势基本一致;随氮肥用量增加土壤呼吸增强,但增幅不大．秸秆还田处理的土壤呼吸作用明显高于秸秆不还田处理和氮肥处理;土壤呼吸同地温存在着显著的指数关系,其中5cm地温同土壤呼吸相关性最好．不同处理、不同深度土层具有不同的Q10值,Q10值随土壤的性状、地温测量的深度和微生物活动的土层深度变化而改变,其本身是温度的函数,随着温度的升高,Q10值呈下降趋势;土壤呼吸与土壤水分的关系较弱,未表现出明显的规律性;冬小麦平均净光合速率与土壤呼吸速率呈相似的变化趋势。从小麦返青到腊熟,冬小麦田表现为CO2的汇．     

东北高寒地区麦田枯枝落叶分解的生态学特征的研究

秸秆还田和农家肥的投入是防止土壤退化和维持健康生态农业的主要前提条件。因此对农田枯枝落叶分解转化的规律及影响因素进行研究是非常重要的。枯枝落叶的物质转化过程与土壤环境的生物因素和非生物因素都密切相关。土壤动物是有机质分解 -腐殖化作用机制的主要环节。一方面 ,它对损耗有机质有直接影响 ;另一方面 ,它对微生物种群起一种真正的生物和能量的过滤作用[9] 。土壤动物对有机残体的机械粉碎作用使真正的“分解者”微生物和有机残体的接触面显著增大。同时有机残体经土壤动物消化道作用变得柔软湿润。也有利于土壤酶的作用。此外…     

Identification of a complete set of isogenic wheat/rye D-genome substitution lines by means of Giemsa C-banding

Summary A complete set of isogenic wheat/rye D-genome substitutions were produced by crossing an inbred line of spring rye Secale cereale L. cv. Prolific to a tetraploid wheat, the A-and B-genomes of which had previously been extracted from hexaploid wheat, Triticum aestivum L. em Thell. cv. Thatcher. After chromosome doubling, the derived hexaploid triticale (x Triticosecale Wittmack) was backcrossed to 6x Thatcher and selection for wheat/rye substitution lines was carried out in BCF₃ to BCF₆ families by using Giemsa C-banding. Five fertile disomic wheat/rye D-genome substitution lines were obtained and their chromosomal constitution was determined to be 1D/1R, 2D/2R, 7D/4R, 6D/6R, 7D/7R. The two remaining 3R and 5R substitutions are at the moment in a monosomic condition. Another 1D/7R substitution was detected but this plant was very weak and sterile, indicating that only substitutions between homoeologous chromosomes result in fertile, vigorous plants. Furthermore, many rye telocentrics as well as rye-rye and rye-wheat translocations were selected. Since all lines selected in this program share the same genetic background of Thatcher wheat, genetic heterogeneity is excluded. The material is very useful, therefore, for analyzing the effects of different rye chromosomes or chromosome segments in an otherwise homozygous background.Contribution No. 797     

温带红松阔叶混交林凋落叶与主要大型土壤动物热值的季节变化

对温带红松阔叶混交林不同种类凋落叶、混合凋落叶和主要大型土壤动物的干质量热值及季节变化规律进行了研究.结果表明：不同种类凋落叶和3种大型土壤动物的干质量热值不同,且其季节变化规律存在一定的差异.红松凋落叶的干质量热值平均值最高(19.71 kJ·g^-1),枫桦(18.22 kJ·g^-1)、紫椴(18.13 kJ·g^-1)、混合凋落叶(17.91 kJ·g^-1)居中,水曲柳(16.94 kJ·g^-1)和色木槭(16.25 kJ·g^-1)最低.红松和色木槭凋落叶干质量热值随凋落叶分解进行呈逐渐降低趋势,水曲柳凋落叶干质量热值季节变化较小,而紫椴、枫桦和混合凋落叶干质量热值次年有上升的趋势.大型土壤动物中,蜈蚣(22.07 kJ·g^-1)的干质量热值最高,蚯蚓(16.72 kJ·g^-1) 次之,马陆(13.28 kJ·g^-1)最低.蚯蚓和马陆干质量热值的季节变化规律一致,蜈蚣干质量热值的季节变化规律则有所不同.凋落叶和3种大型土壤动物干质量热值的季节变化之间没有明显的相关性.     

Oxygen evolution by Photosystem II: The contribution of backward transitions to the anomalous behaviour of double-hits revealed by a new analysis method

Backward transitions in the analysis of oxygen production under flashing light were introduced by Packham et al., 1988, Photosynth. Res. 15: 221–232. In order to take backward transitions into account, a new method of analysis is presented: the eigenvalue method. This method is based on the recurrence relation of oxygen production with four coefficients (also known as the four sigma coefficients). It shows less susceptibility to round-off errors than other methods and permits the computation of double-hits directly from the coefficients, which was not possible before. With it we discovered that the inconsistent behaviour of double-hits observed previously under low flash intensities or low flash frequencies was mainly due to the inclusion of the backward transitions into the double-hit probability. In these conditions backward transitions seemed to be due either to the combination of an S-state deactivation and a miss, or to two S-state deactivations and a single-hit.In the presence of 3-(3, 4-Dichlorophenyl)-1, 1-dimethylurea (DCMU), the previous methods of sigma analysis failed. In contrast, the new method resolved all four S-state probabilities; thus it has the further advantage of being more robust (robustness being defined as the ability to yield a meaningful answer under difficult conditions).Abbreviation: DCMU 3-(3, 4-Dichlorophenyl)-1, 1-dimethylurea     

Vectorial and Octupolar Components of the First-Order Hyperpolarizability in Push-Pull Benzopyranic Series

Vectorial (weight 1) and octupolar (weight 3) components of the first-order hyperpolarizability are computed using the PM3/RHF/FF method following two different decomposition schemes. These calculations evidence the importance of the weight 3 component of the tensor even in push-pull molecules. The values, output from the two decomposition schemes, are different but show the same evolutionary trend within benzopyranic molecule series. The square root of a macroscopic square average quantity ,²)^1/2 (which is usually determined in elastic second-harmonic light scattering experiment) is then computed and compared to the norm of the molecular cartesian tensor.     

Possible complex translocation t(9; 14; 13)(q12;pl?;q31) in mother of a child with 9p-trisomy syndrome

Summary A mentally retarded boy with trisomy 9p is described. This trisomy arose through aberrant segregation of translocation chromosome during meiosis in his mother, who has a complex translocation involving chromosomes 9, 13, and 14. Based on both G-, Q-banding, and DNA replication patterns, the patient's karyotype was identified as 47,XY,-13, +(9;13) (9pter9q12::13q3113qter), +t(13;14) (13pter13q31::14pl?14pter). We suppose his mother's karyotype to be 46,XX,-9,-13,-14,+t(9;13) (9pterq12::13q3113qter), +t(13;14) (13pter13q31::14pl?14pter), +t(9;14) (9qter9q12::14pl?14qter). His phenotypically normal brother and sister are also carriers, having the same translocation chromosome as their mother. Clinical findings of the patient included peculiar face with hypertelorism, prominent nasal bridge and deformed helix, marked delay of osseous development, hypoplastic phalangia in fingers and toes, dysplastic nails and absence of digital triradii.     

氮肥施用对冬小麦产量、品质和氮素表观损失的影响研究

通过田间小区试验,对施用氮肥造成的冬小麦产量、品质和环境效应进行了研究.结果表明,4个试验点最高产量施N量分别为0、0、79和118 kg·hm^-2,最高籽粒粗蛋白质含量施N量分别为122、100、127和174 kg·hm^-2,小麦收获后0～90 cm土壤剖面硝态氮残留量随施N量的增加呈极显著线性增加,而N表观损失则呈指数增加.在最高产量施N量条件下,小麦收获后0～90 cm土层硝态氮残留保持86～115 kg·hm-2,N表观损失为2～32 kg·hm^-2,低于最高籽粒粗蛋白含量施N量时的土壤剖面硝态氮残留量(106～168 kg·hm^-2)和N表观损失量(14～56 kg·hm^-2).综合考虑冬小麦产量、品质和环境安全,最高产量施N和氮肥施用的环境效应可以通过优化施N进行协调.     

不同类型土壤有机碳分解速率的比较

通过室内培育实验研究了黑土、潮土和红壤有机碳的分解速率.结果表明:不同类型土壤有机碳的分解速率常数存在显著差异(P<0.05),黑土、潮土和红壤有机碳的分解速率常数分别为2.2×10-4.d-1、6.0×10-4.d-1和3.4×10-4.d-1.回归分析发现,土壤pH与有机碳分解速率常数呈极显著相关关系,pH<5.5或>8.0时,分解速率常数均大幅提高.土壤中粘粒 粉粒含量与3种类型土壤有机碳的分解速率常数呈极显著负相关,表明粘粒 粉粒含量是3类土壤有机碳分解速率存在差异的主导因子.