浙江省生态公益林碳储量和固碳现状及潜力

生态公益林是为保护和改善人类生存环境,维持生态平衡而建立的。以浙江省的生态公益林为研究对象,共调查和估算了全省21个县149个样地(年龄从5a到50a),包括常绿阔叶林、针阔混交林、马尾松林和杉木林4种主要林型的碳储量和碳平衡。结果说明:浙江省生态公益林生态系统碳密度的加权平均值为164.43tC.hm-2;其中常绿阔叶林生态系统碳储量最高,达216.18tC.hm-2;针阔混交林其次,达181.36tC.hm-2;针叶林最低。浙江省森林以幼龄林(小于30a的占87.5%)和马尾松林(大于55%)为主离成熟状态还相差很远,尤其是针叶林远低于全国平均水平和中高纬度地区碳密度。全省生态公益林净生态系统生产力加权平均得0.08tC.hm-.2a-1,在碳积累上还有很大的潜力。通过封育改造、择伐补阔或以灌促阔等森林管理措施,加快针叶林向针阔混交林直至常绿阔叶林演替,将最大化中国亚热带地区的幼林或受干扰森林的未来碳储量(最高增长31.44%),并成为较大的碳汇。     

台湾常绿阔叶林主要类型及其与大陆常绿阔叶林的关系

 文中采用“常绿阔叶林”的广义概念,系指分布在热带以外、由常绿阔叶乔木组成林冠的森林植被类型。台湾和中国大陆东南部是常绿阔叶林分布中心。根据群落外貌结构以及生境特征将台湾常绿阔叶林分为3个亚类：1）亚热带适雨常绿阔叶林,2）亚热带季节常绿阔叶林,3）山地常绿阔     

浙江天童地区常绿阔叶林退化对土壤养分库和碳库的影响

为了解常绿阔叶林退化对土壤碳库和养分库的影响,采用空间代替时间的研究方法,以常绿阔叶林顶级群落为参照,选择了次生常绿阔叶幼年林、次生针阔混交林、次生针叶林、灌丛和灌草丛代表不同的退化类型,分别对其土壤氮磷养分库、碳库进行了调查和分析。结果表明：土壤氮库贮量从大到小依次为,成熟常绿阔叶林、次生常绿阔叶幼年林、灌丛、次生针叶林、灌草丛和次生针阔混交林;土壤总磷含量也是在成熟林最高,次生针阔混交林和次生针叶林的总磷含量显著高于次生常绿阔叶幼年林和灌丛;土壤有机碳含量从高到低依次为：成熟常绿阔叶林,次生针叶林、次生常绿阔叶幼年林、灌丛、灌草丛和次生针阔混交林;土壤铵态氮在成熟林、灌丛和灌草丛的库容量最大,其次分别为次生幼年常绿阔叶林、次生针阔混交林,最小的为次生针叶林;硝态氮则在灌草丛的库容量最大,其次分别为次生针叶林、次生针阔混交林和成熟林针叶林,最小的为次生常绿阔叶幼年林和灌丛。统计显示,常绿阔叶林退化不仅导致土壤有机碳库含量的显著下降,也使得土壤氮磷养分库含量显著下降。可以认为,砍伐导致的大量生物量输出和森林管理措施的影响,植物种类组成的改变,土壤物理性质的改变以及养分和有机碳的主要生物化学转化环节发生改变是导致此类变化的主要因素,常绿阔叶林顶极群落土壤是该地区土壤的最大养分库和碳库。     

基于InVEST模型估算富阳市森林生态系统碳储量

基于森林资源遥感影像数据资料和ArcGIS10.0软件,以属于典型亚热带气候的富阳市为案例,运用InVEST-Carbon模型对其森林生态系统碳储量进行估算,可视化定量富阳市森林生态系统碳储量并明确其空间分布规律。结果表明：富阳市森林生态系统碳储量分布具有明显的区域差异性,由东向西呈现高－低－高－低的分布带规律。富阳市森林生态系统总的碳储量为26.7437×106 t,其价值量为39.9042亿元;得出富阳市各类森林类型平均碳密度的高低分布为常绿阔叶林碳密度>针阔混交林碳密度>竹林碳密度>马尾松林碳密度>杉木林碳密度,这与浙江省生态公益林各主要林型的碳密度分布规律基本一致,得到其森林生态系统总的碳密度约为180.75 t.hm-2,高于浙江省生态公益林平均碳密度和全国森林平均碳密度。与基于森林二类清查资料,由生物量与蓄积量的关系式估算出的碳储量(28.3780×106 t)相差不大,InVEST模型可适用于森林生态系统碳储量的总体估算。通过研究可以得出,InVEST模型评估结果简明直观,导入较少的数据,将量化的森林碳储量以地图的形式表现出来。 InVEST模型还可用于对未来或多种模拟场景情况下的预测估算等,可为政府、非盈利组织和公司企业等自然资源的管理提供决策信息,其多功能和模块化的设计为权衡评估得失提供了有效的工具。     

浙江省生态公益林植被恢复过程中物种组成及多样性的变化

在浙江省生态公益林区域的现状植被中分析了6种主要群落类型的物种组成和多样性的变化格局,包括演替系列中的2种灌丛、松优势林、2种混交林和常绿阔叶林。结果表明含松较多的灌丛和松优势林常分布在环境退化较严重(土层瘠薄)的生境中,其中灌木层主要由阳性的映山红、木、白栎等组成,常绿阔叶林优势种木荷、青冈、苦槠、甜槠等在其中偶见,因此推断其自然恢复为常绿林的速度慢;含常绿阔叶树较多的灌丛及含松较少的混交林分布在土层较厚处,木荷、青冈、苦槠、甜槠等的频度和重要值都较大,较容易自然恢复为常绿阔叶林。各种群落中物种多样性指数——Gleason、Shannon-Wiener、Simpson指数基本上以常绿阔叶林为最高,其次是含松较少的混交林,含松较多的灌丛和松优势林各种多样性指数最低。本研究显示我国中亚热带东部森林植被恢复途径有3条:(1)灌草丛→针叶林(松)→针(松)阔混交林→常绿阔叶林;(2)灌草丛→针(松)阔混交林→常绿阔叶林;(3)灌草丛→常绿阔叶林。这意味着本区域的常绿阔叶林恢复可以不必经历松林阶段,在生境条件较好的地方通过人工干预、补种常绿阔叶树可以加速常绿阔叶林恢复。     

基于森林资源清查资料分析山东省森林立木碳储量

利用山东省第7次森林资源清查数据,采用生物量-蓄积量转换函数和平均生物量法,结合不同树种的含碳率,研究山东省森林生态系统立木碳储量、碳密度及其按优势树种、龄组和林种的分布特征.结果表明: 2007年山东省森林立木碳储量为25.27 Tg,其中,针叶林、针阔混交林和阔叶林的立木碳储量分别占全省立木碳储量的8.6%、2.0%和89.4%.不同林龄组的立木碳储量大小顺序为幼龄林>中龄林>成熟林>近熟林>过熟林,其中幼龄林和中龄林占全省立木总碳储量的69.3%.用材林、经济林和防护林的立木碳储量分别占全省立木碳储量的37.1%、36.3%和24.8%.山东省森林平均立木碳密度为10.59 t·hm^-2,低于全国平均水平,主要是由于现有森林用材林和经济林比重高,中幼林多、成过熟林少.
     

粤西南亚热带森林演替过程中的生物量与净第一性生产力动态

以粤西黑石顶自然保护区为对象,探讨了南亚热带森林群落演替系列上3个主要演替阶段的代表类型：针叶林(马尾松群落)、针阔混交林(马尾松+吊皮椎+木荷+枫香群落)、南亚热带常绿阔叶林(粘木+小叶胭脂+光叶红豆+黄果厚壳桂群落)的生物量和净第一性生产力及其分配规律。结果表明,针叶林生物量为246．697t·hm^-2,净第一性生产力为14．715t·hm^-2·yr^-1;针阔混交林生物量为287．367t·hm^-2,净第一性生产力为17．179t·hm^-2·yr^-1;常绿阔叶林生物量为357．976t·hm^-2,净第一性生产力为18．730t·hm^-2·yr^-1,可见黑石顶自然保护区南亚热带3种森林群落的发展阶段已比较接近,即针叶林、针阔混交林较为成熟,常绿阔叶林相对年轻,在不受或低度外界干扰的情况下,随着森林群落的正向演替,其生物量和净第一性生产力均呈增加趋势。     

哀牢山亚热带常绿阔叶林乔木碳储量及固碳增量

为了解哀牢山亚热带常绿阔叶林的乔木碳储量及其固碳增量,利用2005和2008年的植被调查数据,对哀牢山3种主要常绿阔叶林的乔木碳储量及其固碳增量进行了分析。结果表明:原生的中山湿性常绿阔叶林、滇山杨次生林和旱冬瓜次生林的乔木碳储量分别为257.90、222.95和105.39tC·hm-2;中山湿性常绿阔叶林乔木碳储量主要存储在DBH≥91cm的乔木中(34.68%);而次生林的乔木碳储量主要分布在径级21cm≤DBH41cm的乔木中(滇山杨林77.29%;旱冬瓜林69.28%)。由此可见,哀牢山地区原生的中山湿性常绿阔叶林乔木层在碳蓄积方面占主导优势。哀牢山亚热带常绿阔叶林的3个森林类型乔木层均具有固碳增量,即使是原生的中山湿性常绿阔叶林,其乔木层年平均固碳增量也达2.47tC·hm-2·a-1;次生林乔木层的年平均固碳增量约为原生林的2倍,显示了哀牢山亚热带常绿阔叶林乔木层具有较强的碳汇增量。初步估算,哀牢山亚热带常绿阔叶林林区内每年乔木固碳增量为8.52×104tC·a-1。     

不同植被恢复类型的土壤肥力质量评价

科学确定森林土壤肥力指标并进行肥力质量的评价,对立地生产力和多目标森林经营的研究有着重要意义。以采伐(径级12 cm择伐)迹地上发育来的稀树灌丛、针叶林、针阔混交林和常绿阔叶林为研究对象,进行每木调查与群落分析,并比较各群落土壤因子间的差异,用典范对应分析(CCA)和因子分析对土壤肥力质量进行定量评价。结果表明,CCA可以有效地筛选土壤肥力质量指标,有助于质量指标的科学确定;土壤肥力质量综合评价分值为稀树灌丛(0.438)常绿阔叶林(0.414)针阔混交林(-0.170)针叶林(-0.331);演替初期(19 a)的植被恢复并未使土壤结构发生明显变化,土壤肥力质量是下降的;无人为干扰的3种群落类型,针叶林表现为更高的生物量积累,而天然更新的常绿阔叶林则更有利于生物多样性的增加与土壤养分的保蓄。     

四川省峨眉山森林植被垂直分布的初步研究

本文对四川省峨眉山森林植被的垂直分布特点进行了初步研究。文中,采用数量分类的方法,结合对群落生态外貌特点和区系组成的分析,以及群落所处海拔高度,划分出森林植被的垂直带如下：1．常绿阔叶林带 1900米以下;2．常绿、落叶阔叶混交林带 1500米至2000米;3．针阔混交林带 2000米至2500米;4．寒温性针叶林带 2500米至3099米。     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV