山东赤松种群的数量动态

通过静态生命表分析赤松（Ｐｉｎｕｓ ｄｅｎｓｉｆｌｏｒａ Ｓｉｅｂ．ｅｔ Ｚｕｃｃ．）种群的生命结构与数量动态。结果表明,赤松种群具有不同年龄等级结构,死亡高峰出现在５～１５年,此时正是幼龄期向成年期的过渡阶段,度过此阶段的赤松个体大多能达到生理寿命。由此看出,赤松种群静态生命表能较精确地反映赤松种群的数量动态规律。     

赤松纯林林分特征对昆嵛山鳃扁叶蜂发生量的影响

为探讨昆嵛山鳃扁叶蜂的发生与天然赤松纯林的林分特征及其自然分布的关系,依托昆嵛山森林生态定位研究站所设立的40块永久性样地,比较了群落自然演替13 a的赤松种群特征以及林内灌草多样性指数,并分析了虫口密度与赤松林分特征的关系。结果表明,13 a自然生长,赤松种群的径级分布和高度结构出现显著变化。赤松种群中占总数60%的林木径级为5 cmDBH≤25 cm,比1996年高51%;而约占67%的赤松个体高度在2 m到10 m之间,比1996年高57%。同时种群密度从1996年的平均超过13000株/hm2降到了2008年的平均2377株/hm2。赤松林内灌草Shannon多样性指数(H)和均匀度指数(JS)分别为2.50和0.79,分别低于1996年的(H)2.69和(JS)0.85,暗示赤松纯林生物多样性有降低的趋势。昆嵛山鳃扁叶蜂的虫口密度与赤松林分的郁闭度和赤松分布的海拔高度呈极显著相关关系、相关系数分别为R=0.931、P=0.002和R=0.924、P=0.003;与林分密度(R=0.780,P=0.038)、林木胸径(R=0.816,P=0.025)呈显著相关关系,而与树高以及树龄关系不显著。昆嵛山鳃扁叶蜂虫口密度的分布格局似乎非常符合"资源集中"假说。     

长白山地区天然赤松林群落学特性的研究

对赤松群落的组成。生活型谱,更新,演替及主要类型林分的生长特点等的分析结果表明：长白山地区的天然赤松林群落种类组成简单,缺乏固有种,群落尚处于演替的初级阶段,干扰行为将严重地影响着群落的演替方向;更新种群呈弱度的聚集型空莘格局,且缺乏演替层;榛子－赤松林的生产力较高,胡枝子－赤松林,草类－赤林次之,杜鹃－赤松林生产力最低。此外,文章还对不同类型的林分的经营措施提出了建议。     

天然赤松个体生物量的研究

对延边地区不同密度天然赤松林中不同生长势的赤松个体地上部生物量进行了研究。结果表明,不同生长势赤松生物量变化受密度影响的顺序为：优势木〈平均木〈被压木;各器官生物量分配比例受密度影响的顺序为：干〉枝〉叶〉皮。不同生长势赤松的生物量垂直分布虽然各具特点,但都表现为：树干和树皮生物量主要分布在６ｍ树高范围内,树枝则集中在６～１０ｍ范围,针叶在上、中、下３层林冠中均分,上层林冠的枝叶量受密度影响最小。     

山东赤松种群的个体生长规律

利用Logistic增长模型对山东赤松 (PinusdensifloraSieb .etZucc .)种群个体生长规律进行了初步研究。结果表明 ,赤松个体生长密切符合Logistic方程 ;人工林个体生长好于天然次生林 ;人工林与次生林个体生长规律一致 ;树高成熟龄和连年生长量最大时年龄出现最早 ,胸径成熟龄和连年生长量最大时年龄出现较晚 ,材积成熟龄和连年生长量最大时年龄出现最迟     

天然赤松个体生物量的研究

对延边地区不同密度天然赤松林中不同生长势的赤松个体地上部生物量进行了研究.结果表明,不同生长势赤松生物量变化受密度影响的顺序为:优势木<平均木<被压木;各器官生物量分配比例受密度影响的顺序为:干>枝>叶>皮.不同生长势赤松的生物量结构在林分密度达到Ⅲ级时发生显著变化,其中平均木的变化与林分基本相同.不同生长势赤松的生物量垂直分布虽然各具特点,但都表现为:树干和树皮生物量主要分布在6m树高范围内,树枝则集中在6～10m范围,针叶在上、中、下3层林冠中均分,上层林冠的枝叶量受密度影响最小.     

昆嵛山天然赤松种群的数量特征及更新动态

1　前　言赤松(ＰｉｎｕｓｄｅｎｓｉｆｌｏｒａＳｉｅｂ.ｅｔＺｕｃｃ.)天然分布于朝鲜、日本和中国,它在我国的天然分布从黑龙江东南部(宁安、东宁)、吉林东部(长白山)、辽东半岛经山东半岛(昆嵛山、崂山、沂山东部)到江苏东北部云台山区,是我国暖温带沿海地区温性针叶林的主要建群种之一[1]。昆嵛山地处山东半岛东端,位于Ｎ37°16′,Ｅ121°43′附近,是赤松在山东半岛的最集中分布地。赤松林在该地区从山麓一直到海拔800ｍ左右都有分布,并与落叶栎林共同组成该地区的地带性天然次生森林植被[2],在调节生态系统结构与功能方面起到重要作用…     

黑龙江省鸡东县兴凯赤松资源调查

本文利用样地抽样,并结合二类调查的成果进行调查统计,对黑龙江省鸡东县的兴凯赤松进行调查,得出了鸡东县兴凯赤松的总株数和蓄积。     

赤松次生林天然更新幼树数量通径分析

用常规方法对山东半岛赤松次生林天然更新状况进行了为期4年的观测研究。运用电子计算机对原始数据进行了通径分析程序运算。结果表明,林分郁闭度、灌草层总盖度对赤松更新幼树数量的影响最大,二者都以直接效应为主,是影响赤松次生林天然更新最重要的因子。坡度与上层厚度代表地形和土壤条件。对赤松更新幼树的数量的影响小于郁闭度和群落总盖度,二者主要通过影响其它因子而间接作用于赤松次生林的天然更新。赤松林木密度与赤松更新幼树数量的关系不密切,对赤松次生林天然更新的作用较小。赤松林地一般无裸岩,故裸岩面积所占百分比对赤松幼树数量的作用不显著。通径分析能够表明变量之间作用的因果关系,更深刻地揭示变量之间的关系。     

山东省台上金矿区赤松林叶绿素含量的季节动态

在1991年春、夏、秋三个季节对山东省招远市台上金矿区赤松林叶绿素含量的变化进行了测定,并与背景区作比较,对金矿区和背景区赤松针叶中的Au、Ag、Cu、Pb元素含量也进行了比较。金矿区和背景区Au、Ag、Cu、Pb元素含量有明显差异,金矿区高于背景区数倍,这对赤松的生长有一定影响,与叶绿素含量有一定的正相关;无论金矿区还是背景区,赤松一年生叶和二年生叶的叶绿素总量变化规律大体一致,都是春季较低,随气温上升而开始增加,至夏末达到最大值,然后从秋季开始下降,金矿区叶绿素总量低于背景区,一年生叶略高于二年生叶;当叶绿素总量变化时,叶绿素a/b的比率稍有波动,但几乎保持不变,金矿区和背景区也无差异。     

Genetic divergence, range expansion and possible homoploid hybrid speciation among pine species in Northeast China

Although homoploid hybrid speciation in plants is probably more common than previously realized, there are few well-documented cases of homoploid hybrid origin in conifers. We examined genetic divergence between two currently widespread pines in Northeast China, Pinus sylvestris var. mongolica and Pinus densiflora, and also whether two narrowly distributed pines in the same region, Pinus funebris and Pinus takahasii, might have originated from the two widespread species by homoploid hybrid speciation. Our results, based on population genetic analysis of chloroplast (cp), mitochondrial (mt) DNA, and nuclear gene sequence variation, showed that the two widespread species were divergent for both cp- and mtDNA variation, and also for haplotype variation at two of eight nuclear gene loci surveyed. Our analysis further indicated that P. sylvestris var. mongolica and P. densiflora remained allopatric during the most severe Quaternary glacial period that occurred in Northeast China, but subsequently exhibited rapid range expansions. P. funebris and P. takahasii, were found to contain a mixture of chlorotypes and nuclear haplotypes that distinguish P. sylvestris var. mongolica and P. densiflora, in support of the hypothesis that they possibly originated via homoploid hybrid speciation following secondary contact and hybridization between P. sylvestris var. mongolica and P. densiflora.     

江苏省云台山宿城自然保护区赤松林、年龄结构及其更新的特点

 本文以植被样地调查和树木年轮数据为依据,采用空间代替时间的方法定量地论述了宿城自然保护区赤松林群落区系、种群年龄结构及其更新的特点。通过对群落区系和种群动态两个重要方面的分析,力图为探讨其群落稳定性提供证据。本群落区系组成丰富,以北温带成分为主并含有较大比重泛热带成分,特别是与我国华北山东半岛南部成分具有密切联系。在主林层中,林木大小等级和年龄等级分布都遵循倒“丁”形曲线。林下一年生幼苗枯损率,几乎接近100%。林冠下幼树枯死约占一半,而林冠层枯立木占总活立木数的4%。所有这些信息表明：该种群是以幼苗补员与幼树枯损的平衡来维持其特定的持续生存。从郁闭林冠下幼苗、幼树高枯损率证明其更新速度缓慢,但很有可能由林中空地来更替。本文所建立的种群结构动态模型结果表明：宿城亦松种群现阶段是稳定型种群。论其群落性质则应属于具有南北过渡特点的华北型地文(Physiographic)顶极群落。     

Radial growth response of Pinus densiflora and Quercus spp. to topographic and climatic factors in South Korea

Aims This study aimed to develop radial growth models and to predict the potential spatial distribution of Pinus densiflora (Japanese red pine) and Quercus spp. (Oaks) in South Korea, considering topographic and climatic factors.Methods We used a dataset of diameter at breast height and radial growth estimates of individual trees, topographic and climatic factors in systematic sample plots distributed over the whole of South Korea. On the basis that radial growth is attributed primarily to tree age, we developed a radial growth model employing tree age as an explanatory variable. We estimated standard growth (SG), defined as radial growth of the tree at age 30, to eliminate the influence of tree age on radial growth. In addition, SG estimates including the Topographic Wetness Index, temperature and precipitation were calculated by the Generalized Additive Model.Important findings As a result of variogram analysis of SG, we found spatial autocorrelation between SG, topographic and climatic factors. Incremental temperature had negative impacts on radial growth of P. densiflora and positive impacts on that of Quercus spp. Precipitation was associated with positive effects on both tree species. Based on the model, we found that radial growth of P. densiflora would be more vulnerable than that of Quercus spp. to climatic factors. Through simulation with the radial growth model, it was predicted that P. densiflora stands would be gradually replaced with Quercus spp. stands in eastern coastal and southern regions of South Korea in the future. The models developed in this study will be helpful for understanding the impact of climatic factors on tree growth and for predicting changes in distribution of P. densiflora and Quercus spp. due to climate change in South Korea.     

Development and arterial supply of the supraventricular crest during the human embryonic and fetal periods

Several works have concerned themselves with the anatomy of the supraventricular crest, for example, analyzing its role in the physiology of the right ventricle; nevertheless, its structure and arterial supply have been less studied. We have studied the morphogenesis of the architecture and the arterial supply of the supraventricular crest, in 25 embryos and human fetuses of 13-71 mm crown-rump length. The muscular organization of the crest (proper muscular bundles and parietal bundles of the right ventricle) and the development of the supraventricular crest's artery as well as its trajectory and its distribution during the fetal period were examined.     

利用I&和*m指标法对山东赤松种群空间分布格局纹理的研究

赤松 (Ｐｉｎｕｓｄｅｎｓｉｆｌｏｒａ)是重要的造林先锋树种 ,在我国主要分布于辽东半岛南部至江苏北部云台山之间的温带沿海地区 ,山东为其主要分布区。赤松林作为我国暖温带落叶阔叶林区域的温性针叶林类型 ,是山东最主要的针叶林 ,总面积达 2 .6 6 7×10 5ｈａ以上 ,木材蓄积量为 1.2× 10 6ｍ3 ,分别占全省森林总面积的 2 0 .19%及木材蓄积量的 14.4 9%。但自 2 0世纪 70年代以来 ,赤松受到“两虫”(松毛虫、松干蚧 )的严重危害 ,加上纯林太多和物种多样性指数低等原因 ,以至目前在山东难以找到大片的成年赤松林[1] 。为保护和发展这…     

辽宁东部的主要植被类型及其分布

辽宁东部位于铁岭一营口一线以东地区。北部为山地,属于长白植物区系区。南部为辽东半岛丘陵,属于华北植物区系区,并具有一些耐寒性的亚热带植物。红松(Pinus koraiensis)、沙松(Abies holophylla)—阔叶混交林和油松 (Pinus tabulaeformis)、赤松(P.densiflora)、落叶阔叶林是辽宁东部的地带性植被。但是,目前次生的蒙古栎(Quercus mongolica)林和各类灌丛分布很广。以开原一南杂木一青城子一青椅山线为界把辽东分为两个植被地带：1)北部为温带针叶阔叶混交林地带;2)南部为暖温带落叶阔叶林地带。在暖温带落叶阔叶林地带内,熊岳一青椅山线的东南部为亦松栎林亚地带,西北部为油松栎林亚地带。     

A model for nonlinear stochastic behavior of the pupil

In binocular fusion, pairs of left and right stimuli yielding the same brightness perception constitute an equibrightness curve in a coordinate system whose ordinate and abscissa correspond to the left and right stimulus strengths. A neural network model is presented to elucidate the characteristics of the curve. According to the model, Fechner's paradox is due to the threshold characteristics of the neuron. If the shapes or movements are radically different between the left and right stimuli, the retinal rivalry is caused. That is, only the left stimulus is perceived at one moment and the right stimulus at another moment. The period of left or right eye dominance alternates randomly from time to time. The distribution of the period is approximate to the gamma distribution. In order to account for this fact, a neural network model is proposed, which consists of a pair of neurons receiving inputs with stochastic fluctuations. The computer simulation was carried out with satisfactory results. The model of retinal rivalry is integrated with that of brightness perception.