四川遂宁地区石油污染土壤中丛枝菌根真菌资源调查研究

调查研究了四川遂宁地区磨溪油田石油污染土壤中丛枝菌根(AM)真菌资源和宿主植物根系侵染状况。结果表明,所调查的14种植物中13种能形成AM,占93%。菌根侵染率为17%~69%,菌根侵染强度为2%~24%,表明石油污染区植物具有较强的菌根依赖性。分离出AM真菌16种,其中缩球囊霉(G.constrictum)和摩西球囊霉(G.mosseae)为该区域优势种;描述了种的形态学特征,并对宿主植物根际土壤AM真菌的分布状况进行了初步探讨。     

Neutral macroecology

The central themes of community ecology-distribution, abundance, and diversity-display strongly marked and very general patterns. These include the log-normal distribution of abundance, the relation between range and abundance, the species-area law, and the turnover of species composition. Each pattern is the subject of a large literature that interprets it in terms of ecological processes, typically involving the sorting of differently specialized species onto heterogeneous landscapes. All of these patterns can be shown to arise, however, from neutral community models in which all individuals have identical properties, as the consequence of local dispersal alone. This implies, at the least, that functional interpretations of these patterns must be reevaluated. More fundamentally, neutral community models provide a general theory for biodiversity and conservation biology capable of predicting the fundamental processes and patterns of community ecology.     

水稻花粉扩散源强估算方法研究

[目的]验证二维通量积分法估算水稻花粉源强的可行性。[方法]利用2008年南京开花期稻田水稻花粉扩散的源强试验资料,分析花粉在稻田上方的分布规律和影响因素,并利用二维通量积分法计算源强大小。[结果]水稻花粉在源内的分布规律不受品种、田块面积的影响,花粉数量在下风方向逐步累积,随离中心距离的分布呈现倒“S”型规律,水稻冠层上方花粉浓度随高度增加而递减,影响冠层上方花粉分布的主要因素是稻田上方的风向、风速和开花量。两优培九花粉扩散源强为开花期花粉总量的1．8％,符合实际情况。[结论]二维通量积分法是估算水稻花粉扩散源强简单而有效的方法。     

入侵杂草小飞蓬和钻形紫菀种子风传扩散生物学特性研究

种子的风传扩散是菊科入侵杂草的主要扩散方式之一,植物自身的传播特性和外在环境因子决定了种子扩散格局。从种子释放高度、沉降速度、脱落行为等内在因子出发,研究了两种在我国广泛分布的典型菊科入侵种小飞蓬和钻形紫菀自身的传播特性与风传扩散特征的关系。结果表明,小飞蓬和钻形紫菀的沉降速度均较小,分别为41.4cm·s-1和30.7cm·s-1,在空中停留时间长,且种子的脱落方式为非随机脱落,脱落概率大致与风速的平方成正比;种子的释放高度在种群内部存在很大的差异,显著影响种子的扩散距离。相比而言,小飞蓬种子的沉降速度大、释放高度高、远距离扩散(>100m)的概率大,扩散距离更远。研究表明了植物自身的传播特性对种子风传扩散的重要性,也为其他菊科入侵杂草种子风传扩散的研究提供了科学依据。     

沙质草地裸斑植被恢复:种子传播和种子形态研究

荒漠化导致草地中形成大量裸斑,笔者通过监测传播到裸斑的种子,分析种子传播在裸斑的时空分布,探索种子形态、传播媒介对种子传播的影响。结果表明,传播到裸斑的种子为415～991粒/（m2.a）;传播种子的分布具有季节差异,70%的种子集中分布在59、、10月,6、78、1、1月一般低于150粒/m2;传播种子分布无空间差异,在裸斑不同方位和圈层呈均衡分布;种子形状和重量是影响种子传播到裸斑的重要因素。种子传播的时间分布格局、种子形态影响种子侵入裸斑,进而影响其植被自然恢复。     

化学防治红脂大小蠹的策略与实践

该文研究了红脂大小蠹 (DendroctonusvalensLeConte)的空间分布格局 ,为典型的聚集分布 ,提出成虫扬飞阶段化学防治区域 ;通过对该虫聚集机制的研究 ,明确提出虫源树概念及其外表特征 ,极大地缩小了非扬飞阶段化学防治的范围 ;通过越冬规律的研究 ,更加有针对性地提出了仅对数量极少的虫源树根部进行防治的策略 ;采用磷化铝根部土壤熏蒸防治试验 ,有效率达 90 3% .这种以生物学、生态学、行为学为依据科学合理制定的防治策略 ,能有效地减低化学防治对森林生态系统的负面影响 ,有利于油松林生态系统的稳定性以及对有害生物的生态调控 .     

河北安国新“八大祁药”根际AM真菌与土壤因子的关系

研究了河北省安国市新"八大祁药"根际土壤中丛枝菌根真菌(AMF)的菌根结构类型及土壤因子与其侵染率的关系。结果表明:(1)祁花粉、祁紫苑和祁沙参菌根类型为中间型(I型),祁白芷、祁荆芥和祁山药为重楼型(P型),祈菊花、祁薏苡为疆南星型(A型)。(2)新"八大祁药"植物根际AMF种类丰富,共分离鉴定出5属31种。黑球囊霉(G.melanosporum)和摩西球囊霉(G.mosseae)是8种药用植物的共同优势种。(3)新"八大祁药"植物的菌根侵染率主要受其根际土壤蛋白酶活性的影响。这说明,新"八大祁药"能与AMF形成良好的共生关系,并且AMF种类分布和侵染状况与土壤因子有明显的相关性。     

9种风传杂草种子的扩散能力及传播策略

[目的]研究9种风传杂草种子的扩散能力及传播策略。[方法]以9种杂草种子为试验材料,研究其传播能力(沉降速度、水平移动距离)及其与种子形态结构之间的相关性。[结果]就9种种子整体而言,种子的沉降速度与水平移动距离呈极显著负相关。菊科植物种子的沉降速度与果长、毛长呈正相关,而禾本科植物种子的沉降速度与二者呈负相关;菊科植物种子的水平移动距离与果长、毛长呈负相关,而禾本科植物种子的水平移动距离与二者呈正相关,说明菊科植物和禾本科植物种子的传播策略不同,而这种传播策略往往与植物本身生存环境有关。禾本科植物具有横向传播优势。[结论]该研究可为深入了解种子的传播机制以及杂草的入侵防治提供理论依据。     

梅花内生真菌及其多样性

通过采样、组织分离、培养与鉴定,对梅花内生真菌种类、分布及多样性进行了初步研究。结果表明:梅花内生真菌具有丰富的生物多样性,共得到梅花内生真菌15种。其中产孢真菌8属12种,非产孢真菌3种。它们多数为半知菌,少数为接合菌,曲霉1(Aspergillus sp.1)和青霉1(Penicillium sp.1)是梅花内生真菌优势种。梅花内生真菌广泛分布于各种组织内,总定殖率为54.8%,在嫩枝木质部定殖率最高,达65.6%。梅花植物体外部生态环境及内部组织类型对内生真菌的种类与分布均有重要影响。     

宝天曼自然保护区树附生苔藓空间格局分析

采用单变量g(r)函数,选用同质性泊松、异质性泊松、同质性托马斯和异质性托马斯4个零模型,分析了宝天曼自然保护区内1 hm2样地中11种树附生苔藓物种的空间分布格局.结果显示,11个物种中,有6个物种在同质性泊松模型下表现出聚集分布,在同质性托马斯模型下的聚集程度有所减弱,但在异质性泊松模型下完全变为随机分布.与同质性泊松模型下的分布相比,在异质性泊松模型下,有4个物种在较大尺度上的聚集分布变为随机分布;而在同质性托马斯模型下,有2个物种在较小尺度上的聚集分布变为随机分布.研究表明:1)生境异质性和扩散限制均对树附生苔藓空间分布格局的形成有影响,且生境异质性起主要作用;2)生境异质性可在小尺度上影响树附生苔藓的空间分布,扩散限制也能在大尺度上发挥作用.     

Dispersal,environment, and floristic variation of western Amazonian forests

The distribution of plant species, the species compositions of different sites, and the factors that affect them in tropical rain forests are not well understood. The main hypotheses are that species composition is either (i) uniform over large areas, (ii) random but spatially autocorrelated because of dispersal limitation, or (iii) patchy and environmentally determined. Here we test these hypotheses, using a large data set from western Amazonia. The uniformity hypothesis gains no support, but the other hypotheses do. Environmental determinism explains a larger proportion of the variation in floristic differences between sites than does dispersal limitation; together, these processes explain 70 to 75% of the variation. Consequently, it is important that management planning for conservation and resource use take into account both habitat heterogeneity and biogeographic differences.     

濒危植物崂山百合根围AM真菌分布特征

为探明崂山百合种群密度降低过程中根围丛枝菌根(AM)真菌空间分布特征,2014年10月从崂山3个土层采集崂山百合及伴生植物玉竹(Polygonatum odoratum)根围土壤样品,分离鉴定AM真菌种类、测定菌根发育状况和孢子密度、分析AM真菌分布及其与种群密度、土壤因子(土壤有机碳、p H、碱解氮、速效磷等)相关性。从崂山百合根围分离AM真菌4属14种,玉竹根围分离3属11种。崂山百合分布于10~20 cm土层内,根系侵染率随种群密度增大而增加;大密度种群样地玉竹菌根侵染率显著高于小密度种群。崂山百合种群密度对其根系丛枝定殖率无显著影响。10~20 cm、20~30 cm土层崂山百合和0~10 cm、10~20 cm土层玉竹根系泡囊定殖率随各种群密度增大而降低。30~40 cm土层崂山百合、10~20 cm土层玉竹菌丝定殖率随高种群密度增大而增加。种群密度对崂山百合和玉竹根围孢子密度有显著影响。10~20 cm和20~30 cm土层崂山百合根围总球囊霉素含量随崂山百合种群密度增大而降低。10~20 cm和20~30 cm土层酸性磷酸酶和脲酶含量随崂山百合种群密度增大而提高。     

Hydrothermal vent animals: distribution and biology

Hydrothermal vent communities characterized by large clams, mussels, and vestimentiferan worms thrive on chemosynthetic microbial production. There are similarities in the animal distributions at vent communities from 20 degrees S to 46 degrees N on the Mid-Ocean Ridge in the Pacific Ocean and at cold sulfide seeps in the Gulf of Mexico. Vent communities, consisting of at least 16 previously unknown families of invertebrates, are at least 200 million years old. Since the life-span of a vent is only tens of years, the species survive by rapid growth and widespread dispersal of larvae with the subsequent colonization of new vents.     

Adaptation and evolutionary rescue in metapopulations experiencing environmental deterioration

It is not known whether evolution will usually be rapid enough to allow a species to adapt and persist in a deteriorating environment. We tracked the eco-evolutionary dynamics of metapopulations with a laboratory model system of yeast exposed to salt stress. Metapopulations experienced environmental deterioration at three different rates and their component populations were either unconnected or connected by local dispersal or by global dispersal. We found that adaptation was favored by gradual deterioration and local dispersal. After further abrupt deterioration, the frequency of evolutionary rescue depended on both the prior rate of deterioration and the rate of dispersal. Adaptation was surprisingly frequent and rapid in small peripheral populations. Thus, evolutionary dynamics affect both the persistence and the range of a species after environmental deterioration.     

Population cycles in small rodents

We conclude that population fluctuations in Microtus in southern Indiana are produced by a syndrome of changes in birth and death rates similar to that found in other species of voles and lemmings. The mechanisms which cause the changes in birth and death rates are demolished by fencing the population so that no dispersal can occur. Dispersal thus seems critical for population regulation in Microtus. Because most dispersal occurs during the increase phase of the population cycle and there is little dispersal during the decline phase, dispersal is not directly related to population density. Hence the quality of dispersing animals must be important, and we have found one case of increased dispersal tendency by one genotype. The failure of population regulation of Microtus in enclosed areas requires an explanation by any hypothesis attempting to explain population cycles in small rodents. It might be suggested that the fence changed the predation pressure on the enclosed populations. However, the fence was only 2 feet (0.6 meter) high and did not stop the entrance of foxes, weasels, shrews, or avian predators. A striking feature was that the habitat in the enclosures quickly recovered from complete devastation by the start of the spring growing season. Obviously the habitat and food quality were sufficient to support Microtus populations of abnormally high densities, and recovery of the habitat was sufficiently quick that the introduction of new animals to these enclosed areas resulted in another population explosion. Finally, hypotheses of population regulation by social stress must account for the finding that Microtus can exist at densities several times greater than normal without "stress" taking an obvious toll. We hypothesize that the prevention of dispersal changes the quality of the populations in the enclosures in comparison to those outside the fence. Voles forced to remain in an overcrowded fenced population do not suffer high mortality rates and continue to reproduce at abnormally high densities until starvation overtakes them. The initial behavioral interactions associated with crowding do not seem sufficient to cause voles to die in situ. What happens to animals during the population decline? Our studies have not answered this question. The animals did not appear to disperse, but it is possible that the method we used to measure dispersal (movement into a vacant habitat) missed a large segment of dispersing voles which did not remain in the vacant area but kept on moving. Perhaps the dispersal during the increase phase of the population cycle is a colonization type of dispersal, and the animals taking part in it are likely to stay in a new habitat, while during the population decline dispersal is a pathological response to high density, and the animals are not attracted to settling even in a vacant habitat. The alternative to this suggestion is that animals are dying in situ during the decline because of physiological or genetically determined behavioral stress. Thus the fencing of a population prevents the change in rates of survival and reproduction, from high rates in the increase phase to low rates in the decline phase, and the fenced populations resemble "mouse plagues." A possible explanation is that the differential dispersal of animals during the phase of increase causes the quality of the voles remaining at peak densities in wild populations to be different from the quality of voles at much higher densities in enclosures. Increased sensitivity to density in Microtus could cause the decline of wild populations at densities lower than those reached by fenced populations in which selection through dispersal has been prevented. Fencing might also alter the social interactions among Microtus in other ways that are not understood. The analysis of colonizing species by MacArthur and Wilson (27) can be applied to our studies of dispersal in populations of Microtus. Groups of organisms with good dispersal and colonizing ability are called r strategists because they have high reproductive potential and are able to exploit a new environment rapidly. Dispersing voles seem to be r strategists. Young females in breeding condition were over-represented in dispersing female Microtus (17). The Tf(C)/Tf(E) females, which were more common among dispersers during the phase of population increase (Fig. 6), also have a slight reproductive advantage over the other Tf genotypes (19). Thus in Microtus populations the animals with the highest reproductive potential, the r strategists, are dispersing. The segment of the population which remains behind after the selection-via-dispersal are those individuals which are less influenced by increasing population densities. These are the individuals which maximize use of the habitat, the K strategists in MacArthur and Wilson's terminology, or voles selected for spacing behavior. Thus we can describe population cycles in Microtus in the same theoretical framework as colonizing species on islands. Our work on Microtus is consistent with the hypothesis of genetic and behavioral effects proposed by Chitty (6) (Fig. 7) in that it shows both behavioral differences in males during the phases of population fluctuation and periods of strong genetic selection. The greatest gaps in our knowledge are in the area of genetic-behavioral interactions which are most difficult to measure. We have no information on the heritability of aggressive behavior in voles. The pathways by which behavioral events are translated into physiological changes which affect reproduction and growth have been carefully analyzed by Christian and his associates (28) for rodents in laboratory situations, but the application of these findings to the complex field events described above remains to be done. Several experiments are suggested by our work. First, other populations of other rodent species should increase to abnormal densities if enclosed in a large fenced area (29). We need to find situations in which this prediction is not fulfilled. Island populations may be an important source of material for such an experiment (30). Second, if one-way exit doors were provided from a fenced area, normal population regulation through dispersal should occur. This experiment would provide another method by which dispersers could be identified. Third, if dispersal were prevented after a population reached peak densities, a normal decline phase should occur. This prediction is based on the assumption that dispersal during the increase phase is sufficient to ensure the decline phase 1 or 2 years later. All these experiments are concerned with the dispersal factor, and our work on Microtus can be summarized by the admonition: study dispersal.     

乐昌含笑群落的分布格局分析

通过调查乐昌含笑群落,并根据种群聚集度指标,主要对群落内的乔木进行计算分析.结果表明,垂直分布上,乐昌含笑群落呈现稳定的金字塔型生长状态;水平分布上,群落内乐昌含笑的扩散系数(C)=0.38,丛生指数(I)=-0.62,扩散指数(Ⅰδ)-0.18,聚块性指数(M*/(X))=0.99,Cassie R.M.指数(CA)...     

Differential resource utilization by the sexes of dioecious plants

The distribution of male and female plants was examined in five dioecious, wind-pollinated species representing five plant families and two classes (gymnosperms and angiosperms). The arid to semiarid habitats occupied by these species in northern Utah were stratified for sampling into two categories: chronically xeric and seasonally moist. The results show that for all species, males are more abundant on xeric microsites, while females are over represented on the moister parts of each local environment. Differential distribution of the sexes along a soil moisture gradient is a strategy that maximizes seed set of females and pollen dispersal of males; it also tends to minimize intraspecific competition between the sexes.     

野菊内生真菌生物多样性与生态分布

通过采样、分离、培养与鉴定,对信阳地区野菊[Dendranthema indicum (L.) Des Moul.]内生真菌的群落结构及生态分布进行了研究.结果表明,野菊内生真菌具有丰富的生物多样性,分离得到真菌21种,它们多数为半知菌,少数为子囊菌.其中,刺盘孢菌(Colletotrichum spp.)、拟茎点霉(...     

Forests of the past: a window to future changes

The study of past forest change provides a necessary historical context for evaluating the outcome of human-induced climate change and biological invasions. Retrospective analyses based on fossil and genetic data greatly advance our understanding of tree colonization, adaptation, and extinction in response to past climatic change. For instance, these analyses reveal cryptic refugia near or north of continental ice sheets, leading to reevaluation of postglacial tree migration rates. Species extinctions appear to have occurred primarily during periods of high climatic variability. Transoceanic dispersal and colonization in the tropics were widespread at geological time scales, inconsistent with the idea that tropical forests are particularly resistant to biological invasions.     

河北省安国市药用植物AM真菌资源和分布研究

2008年7月,调查分析了河北省安国市10种药用植物根围AM真菌资源和分布。结果表明:10种药用植物均能与AM真菌形成良好共生关系,不同药用植物形成菌根的能力不同,射干孢子密度和总定殖率最高,孢子密度为2 814个/100 g土,总定殖率为100%。白芷、射干和白术形成P-型菌根,而沙参、菊花、南星、防风、黄芪、甘草和黄芩形成A-型菌根。共分离AM真菌3属16种,其中球囊霉属(Glomus)8种、无梗囊霉属(Acaulos-pora)5种、盾巨孢囊霉属(Scutellospora)3种。地球囊霉(Glomus geosporum)和摩西球囊霉(Glomus mossea)是10种药用植物的共同优势种,多梗球囊霉(Glomus multicaule)仅在沙参根区出现,明球囊霉(Glomus clarum)仅在菊花根区出现,细凹无梗囊霉(A.scrobiculata)为南星根区独有。