蚯蚓与微生物的相互作用

蚯蚓从成体到卵内均有微生物,微生物来源于蚯蚓生活的环境,在消化消化道时,随食物进入体内的真菌营养体及大部分细菌被杀死,只有真菌的孢子和部分细菌仍保持生活力,生长缓慢的细菌通过蚯蚓消化道后群体下降;而生长快的细菌,由于在消化道内迅速繁殖,在蚯蚓排泄物中的群体数量甚至会超过进入蚯蚓体内时的数量,蚯蚓能促进土表有益和致病微生物在土壤内从向传播,但也能减轻由病原真菌引起的病害。真菌是蚯蚓食物的一部分,消化     

山西高原植被与土壤分布格局关系的研究

利用ＣＣＡ、ＤＣＣＡ等多元分析方法,在景观尺度上对山西高原植被与土壤分布格局之间的关系进行了分析,所得结论表明：纬向上主要是栗褐土、褐土、风沙土和栗钙土与植被的变化格局相关性较强,由于山西高原南北跨度大,土壤和植被格局纬向变化趋势的一致性十分明显;黄绵土、栗钙土、山地草甸土与植被的经向分布格局密切相关,由于山西高原东西向跨度较小,且大部分地区处于吕梁山与太行山之间,植被和土壤的经向格局梯度不明显;随海拔高度的增加,棕壤、山地草甸土、亚高山草甸土与山西高原植被的垂直分布格局相平行,由于山西高原相对高差较大,这种趋势也非常明显。综合分析还表明了气候、土壤与植被格局的一致性,也反映了地貌对其分布格局的影响     

蓝藻Anabaena 7120的固氮放氢和同化力之间的关系

分子氮和二氧化碳对蓝藻Anabaena 7120固氮的抑制作用可因反应系统中pH值的提高以及对蓝藻进行预照光处理而削弱或消除。分子氢对经预照光处理的蓝藻固氮活性不但不支持,且有削弱。预暗处理的效应恰好相反。蓝藻经低温(4℃)预处理后,分子氢对其固氮活性支持减弱,甚至抑制。蓝藻放氢对分子氢和同化力水平的反应规律在趋势上与固氮基本相同。     

土壤藻类及其生理生态

人类对土壤藻类的认识至少可以追溯到三千多年前的我国诗经时代。Prescott1引用Porterfield2的研究并阐述说:尽管藻类学作为一门科学是由西方文化中诞生的,但最早的文字记载出现在中国的古典著作中,在诗经中人们可以发现采集和食用念珠藻(Nostoc)的文献记录……。他们还提到,古希腊的贤哲对念珠藻也有过观察。       

土壤微生物PCR及分子杂交检测

ＰＣＲ技术在环境微生物的检测方面已得到越来越广泛的应用,Ｓｔｅｆａｎ等［１］利用ＰＣＲ技术检测土壤中的转基因细菌,后来用于检测土壤中不可培养的微生物［２］,跟踪环境中的特定细菌或ＤＮＡ［３］,揭示土壤生态系统的基因多样性［４］等。利用ＰＣＲ技术来检测…     

NUCLEAR ENVELOPE-CHLOROPLAST RELATIONSHIPS IN ALGAE

In Ochromonas danica and two related species (Chrysophyceae) and in Rhodomonas lens and Cryptomonas sp. (Cryptophyceae), the chloroplast is surrounded by an outer double-membraned envelope which lies outside the usual double-membraned chloroplast envelope. At the borders of the area where the chloroplast lies adjacent to the nucleus, this outer envelope is continuous with the outer membrane of the nuclear envelope as a double-membraned outfolding, so that the entire chloroplast in these species lies within a double-membraned sac, one wall of which is the nuclear envelope. In Olisthodiscus sp. (Chrysophyceae ?), each of the small peripheral chloroplasts is surrounded by a similar double-membraned outer envelope, but in this species no connections with the nuclear envelope were observed. In the Ochromonadaceae, a characteristic array of tubules is present within the sac in the narrow space which separates the chloroplast from the nucleus. In the other species studied, tubules are present at places between the chloroplast envelope and the outer envelope. In the Cryptophyceae, the starch grains lie outside the chloroplast envelope, but within the outer double-membraned sac. A double-membraned outer envelope appears to be present outside the chloroplasts of the Phaeophyta and Euglenophyta, but seems to be absent in the other groups of algae.     

MASS CULTURE OF ALGAE FOR FOOD AND OTHER ORGANIC COMPOUNDS

Krauss, Robert W. (U. Maryland, College Park.) Mass culture of algae for food and other organic compounds. Amer. Jour. Bot. 49(4): 425–435. Illus. 1962.—Data are being collected which appear to support the use of unicellular algae for human food. Analyses of proteins, fats, carbohydrates, and vitamins indicate that unicellular green algae, especially Chlorella, should be excellent sources of these nutrients. The effectiveness of the algae for the support of growth of chickens, mice, rats, and rabbits has been found to be good. However, only limited studies have been done with humans. The problem of acceptability varies with the nationality of the subjects and the preparation of the food. Serious gaps still exist both in the technology of production and in the experimentation required to establish nutritional value. Nutrition studies using algae free of bacteria are urgently needed.     

STUDIES ON THE RELATIONSHIPS BETWEEN EARTHWORMS AND SOIL FERTILITY: I. BIOLOGICAL STUDIES IN THE FIELD

Changes in the seasonal activity of several species of earthworms have been followed in a permanent pasture field for 18 months, 1945–6. The two soil conditions which chiefly determine activity are temperature and moisture. Other factors are the occurrence of an obligatory diapause in the two species Allolobophora nocturna and A. longa , and changes in population in A. chlorotica and Lumbricus terrestris.
Soil temperature and soil moisture also determined the weight of soil thrown up in the form of wormcasts during autumn, winter and spring. It is suggested that only two species, A. nocturna and A. longa , are responsible for wormcasts and that the other four common species present play little or no part in this activity.
At Rothamsted it was found that the previous agricultural history of the field is an important factor in determining the fauna. Old permanent pasture is characterized by a high percentage of A. nocturna and a rather lower percentage of A. caliginosa. Ploughing old permanent pasture and reseeding to grass after 1 or 2 years arable reduces the proportions of A. nocturna and A. caliginosa and increases that of Eisenia rosea. Arable fields have A. chlorotica as the dominant species and pasture fields 2–7 years grass after many years of arable fanning still show a high percentage of A. chlorotica and a low proportion of A. nocturna.
A survey of the Carse of Stirling, Scotland, showed that soil type is also an important factor in determining the earthworm fauna. A. caliginosa was the dominant species on the three soil types studied, but the subdominant species varied. On clay soil, A. longa was subdominant; on loam, A. longa and L. rubellus ; on sandy soil, A. longa, L. rubellus and A. chlorotica. The dominant species of pasture land at Rothamsted, A. nocturna , was not found at Stirling.     

开鲁盆地白垩纪沟鞭藻类及其它藻类

本文依据内蒙古自治区开鲁盆地的藻类演化特征,从下到上划分为５个藻类组合,对藻类组合的时代、藻类产出层位的沉积环境作了讨论。     

RELATIONSHIPS BETWEEN PATELLA FERRUGINEA GMELIN, 1791 AND THE OTHER TYRRHENIAN SPECIES OF PATELLA (GASTROPODA: PATELLIDAE)

The external morphology of soft parts of the rare Patella ferrugineaGmelin, 1791 is described, and its relationships with P. caerulea,P. rustica and P. ulys-siponensis are investigated on both morphologicaland electrophoretic grounds. Soft part morphology is a gooddiscriminative tool, but of little help in detecting affinities.Electrophoretic data on 19 presumptive loci suggest that P.rustica is the closest species to P. ferruginea, whereas P.caerulea and P. ulyssiponensis are clustered separately. Meanobserved heterozyg-osities arc higher in P. ferruginea and P.rustica. It is concluded that in case of subdivision of thegenus Patella L., 1758, P. ferruginea and P. rustica shouldbe placed together in the subgenus Patellastra Mon-terosato,1884. (Received 6 January 1993; accepted 23 February 1993)     

同宗配合蜜环菌与欧美异宗配合蜜环菌狭义种的分子系统学关系

从亚洲、欧洲和北美收集18个蜜环菌狭义种菌株,PCR扩增其rDNA的IGS和ITS区域,用AluI、HaeIII、HinfI和TagI四种限制性内切酶进行酶切,同时用随机扩增微卫星(RAMS)多态性,对蜜环菌狭义种的进行了遗传多样性和分子系统学分析。结果蜜环菌狭义种的IGS和ITS-RFLP类型比以前报道的更多,亚洲、欧洲和北美菌株都具有比较明显的特征片段,通过ITS和IGS图谱可将三个大陆的菌株区分开,其中IGS-HinfI图谱能完全区分3个大陆的菌株。RFLP数据的系统学分析表明,该种存在明显的大陆遗传分化,亚、欧、北美的群体分属三个相互独立的进化系,北美群体IGS变异程度较小,ITS变异程度极高;而欧洲群体IGS的变异程度较大,多态性高,ITS变异程度非常小。RAMS系统分析表明,中国、日本和非洲的同宗配合蜜环菌属于一个系统发育系,该发育系同欧洲和北美的异宗配合种的两个发育系分属3个不同的独立进化分支。据此建议欧洲和北美的异宗配合蜜环菌应作为蜜环菌的两个亚种。