广西石灰岩地区蕨类植物区系特征

广西石灰岩蕨类植物区系较为丰富,现已发现38科,93属,393种（变种、变型太区系地理成分复杂多样,属可以划分为11种类型（变型）,种可以划分为13种类型（变型）。本区系具有一定的热带亲缘,热带分布属占73．12％,热带分布种占53．43％。亚洲热带分布及其变型占有较大的比例,表明本区系与亚洲热带植物区系特别是中南半岛区系有密切的亲缘关系。区系的特有性和狭域分布特征十分明显。     

广西那坡及附近地区蕨类植物区系特征与垂直分布研究

那坡植物区系位于北回归线以南,中越二国滇黔桂等四省边区,该类植物非常丰富,现已发现46科,100属,318种。区系地理成分复杂多样,属可以划分为10种类型（变型）,种可以划分为13种类型（变型）。本区系具有明显的热带亲缘,热带分布属占77％,热带分布种占61.95％。亚洲热带分布及其变型占有较大的比例,本区系与亚洲热带植物区系以及云贵高原植物区系有密切的亲缘关系。区系地理成分有明显的垂直分布规律,聚类分析的结果表明,海拔800m是区系地理成分垂直分布的分界线。本文采用多元分析方法对区系内部的分化和区系间的相似性进行了研究。     

广西南部蕨类植物区系研究 Ⅰ.区系特征

广西南部植物区系位于北回归线以南，蕨类植物非常丰富，现已发现５４科、１４１属、５８４种。科、属组成以水龙骨科Ｐｏｌｙｐｏｄｉａｃｅａｅ、金星蕨科Ｔｈｅｌｙｐｔｅｒｉｄａｃｅａｅ、蹄盖蕨科Ａｔｈｙｒｉａｃｅａｅ、鳞毛蕨科Ｄｒｙｏｐｔｅｒｉｏｄａｃｅａｅ四科的属、种成员最多，其中金星蕨科在植物区系中占有重要的位置，是本区系的一个特点；蹄盖蕨属、耳蕨属种类较少是本区系不同于鳞毛蕨－耳蕨植物区系的一个重要特征。区系地理成分复杂多样，属可划分为１２种类型（变型），种可划分为１５种类型（变型）。特有现象明显，中国特有１２７种，占２１．７４％；广西特有２６种，占４．４５％。本区系具有明显的热带性，同时也具有强烈的热带南亚热带过渡性，热带分布属占８３．６８％，热带分布种占６０．６２％。亚洲热带分布及其变型占有较大的比例，表明本区系与亚洲热带植物区系特别是中南半岛区系有密切的亲缘关系。     

陕西武功县土地资源的合理利用

武功县位于陕西关中平原西部,在东经108°1′—108。19′,北纬34。12′—34。26′之间。自然地带处于暖温带半干旱落叶阔叶林草原褐土带。年平均气温12.9℃。年平均降水量637.1毫米:春季降水量131—157毫米,占全年降水量23—24%,有利于冬小麦生长;夏季降水量225—270毫米,占全年降水量39—41%。高温多雨的配合,对秋季作物的生长有利。本区农业     

中国热带亚热带地区旱地土壤资源

中国热带、亚热带地区涉及14个省(区),约217万平方公里,占全国土地面积的22%。本区热量丰富,雨量充沛,≥10℃积温4500-8500℃,年雨量1200-2000毫米,高温与多雨同季,土壤生产潜力甚大。旱地土壤资源是本区粮食作物、热带亚热带经济作物和林牧业发展的重要基地,面积1043万公顷,占全区土地总面积的5.17%,主要分布于低丘岗地及高原山地,共包括以下六种类型(表1)。     

天水市麦积区古树资源分布调查

为摸清天水市麦积区古树资源分布状况,2020 — 2021年采用“古树名木信息管理系统”和古树名木App管理软件对天水市麦积区区内现存古树资源(古树及古树群)进行调查。结果表明,分布于麦积区的古树有333株,隶属23科28属34种(含种下等级),其中一级古树110株,二级古树61株,三级古树162株。现存古树群7个。古树区域分布以甘泉镇最多,有74株;马跑泉镇和麦积镇较多,分别有66、52株。约70%的古树生长势处于濒危衰弱状态。古树科层面的分布区类型有5种,分布区变型有1种;古树属层面的分布区类型有7种,分布区变型有3种。古树区系主要特征为北温带区系成分占优势,表现植物区系由亚热带向温带过渡的特点。     

广州市常见杂草植物区系特征分析

2014—2015年,通过实地样方调查和文献查阅,对广州市常见杂草植物进行统计分析,在选取的36个样点中杂草植物共计39科98属133种,以菊科和禾本科为主。其区系组成成分多样,科的分布类型以世界分布为主,比例超过50%,其次是泛热带分布类型。属的分布类型泛热带分布有45个属,比例为45.92%;世界分布含有16个属,比例为16.33%;两者构成了广州常见杂草植物的属区系主体。在广州的杂草植物中,外来入侵植物有11科19属21种,菊科是主要入侵植物,种数最多;分析其属的分布类型表明,泛热带分布有10属,所占多达52.63%。入侵植物原产美洲居多,以草本植物为主;草本植物能快速适应环境并繁殖。     

黄河上游北川河流域种子植物的区系特征

 北川河流域位居黄河上游地区,生态地位十分重要。流域内有种子植物74科、357属、1006种(含变种、变型)。流域内种子植物区系地理成分复杂多样,种子植物属有12个分布区类型和14个变型,与中国种子植物属的15个分布区类型、31个变型相比,分别占到80．0％和45．2％,类型较为齐全,变型也相当丰富。温带分布的属数及其所占的比例,在该区各分布类型中具有明显优势,其中尤以北温带分布类型更为显著,计有117属,占本区种子植物总属数的32．8％,占全国该类型分布的54．9％。该区植物区系的基本性质是以北温带为主。区系分区归属于泛北极植物区青藏高原植物亚区唐古特地区。植物区系成分的研究,为合理开发、利用、保护当地植物资源,开展科学引种提供了充分的依据。     

延河流域种子植物区系特征与物种空间分布

以延河流域为例,采用环境梯度分层采样技术,对该流域种子植被的区系成分进行调查分析。结果表明,延河流域主要的种子植物区系共涉及57个科、148属、211种,其中裸子植物3科3属3种,被子植54科145属208种。从植物区系科属的分布型看,热带亚热带成分占31．57％,温带成分占28．07％;从属的分布型看,热带亚热带成分占11．72％,温带成分占60．54％。温带成分构成了本区系的主体,本区种子植物区系属温带性质。虽然数量上较整个黄土高原的植物区系成分较少,但这些物种却是该流域种子植物群落的主要构成种,对该区的生态恢复具有更重要的意义。在此基础上,进一步借助物种空间分布与环境要素响应图,分析211个物种分布的环境梯度空间,结果表明,它们可直接满足生态恢复重建的物种选择等需求,具有较好的应用价值。     

鲁中水土保持生态修复区种子植物区系特征

 为鲁中石质山地水土保持生态修复过程中适宜植物种类的选择、保护与合理经营提供理论依据,对淄川峨庄水土保持生态修复区内植物区系组成和地理成分进行分析。结果表明:1)该植物区系内共有种子植物271种,隶属于61科157属,分别占我国种子植物区系科、属、种的17.28%、4.90%和0.998%,其中单种科和极小科（含29种）所含的种数占总种数的91.6%,单种属和含2～4种的属有161个,占总属数的96.18%,可以看出该研究区内植物科和属的分布是比较均匀和丰富的;2)该区植物区系温带成分,特别是北温带成分具有明显优势,热带性质属在该区系中占有较大的比例,说明该地区植物区系与热带植物区系有较密切渊源,并具有一定的亚热带热带区系的过渡性;3)该区植物区系的特有性较低。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.