小词典

根瘤菌在豆科植物根上形成根瘤并与之共生的细菌。能固定空气中的氮素,供给植物利用;同时由植物供给它们有机养料。但根瘤菌专性强,一定豆科根瘤菌,只能与一定豆科植物共生,一般不能交互接种。此外,相当多的非豆科植物,如赤杨、沙棘、杨梅、胡颓子、木麻黄、罗汉松、苏铁等也     

浅谈森林植物的根瘤菌和菌根

被誉为植物“炊事员”的根瘤菌和菌根菌是土壤中的一对宝。很多人熟悉根瘤菌,想从根瘤菌打主意,改善植物的营养,提高农林作物的产量。国外就在研究怎样使水稻、小麦、玉米之类感染上根瘤菌。很多人知道豆科植物能与根瘤菌共生,形成固氮的根瘤,却不知道森林植物中有很多非豆科品种也能感染根瘤菌,产生固氮的根瘤。而对于森林植物的菌根,则知之更微。     

根瘤菌

根瘤菌该产品适合于中小企业尤其是乡镇企业组织生产，主要应用于农业、蓄牧业及种植业。豆科植物（农作物及稗草）种子接种根瘤菌后播种，能供植物自行固氮，达到增产目的，植物收获后仍遗留在土壤中的大量氮素又可供下茬作物使用，豆科植物与根瘤菌共生，每亩每年能围绕...     

用切根培养技术检验不同糖类对豆科植物根瘤形成的影响

人们知道,各种环境因素包括土壤中的营养状况和植物周围的局部条件,都影响豆科植物的根瘤形成。已经证明,光的强度和日照长度显著影响根瘤菌形成,而这种影响是由于光合作用调节植物体内碳水化合物水平所致。叶面施用糖也证明了刺激植物根瘤菌的形成。为了准确的观测糖对根瘤菌形成的直接影响,我们采用了切根培养技术,这则简报利用修改了月 Raggio 的方法,揭示了各种糖对根瘤菌形成的影响。用70%乙醇对绿豆种子杀菌1分钟,再用10%次氯酸钠溶液浸泡10分钟,然后用无     

植物间的“亲家”

植物之间,有取长补短相互帮助的"亲家". 有些植物的分泌物,不但彼此无妨,而且互助互利. 春天,在冬小麦地里行间播种豌豆、棉花,可以收到互相促进,增加产量的效果.小麦、玉米和瓜类根系的分泌物彼此有利,玉米和大豆是"亲家",玉米需要氮肥,大豆的根瘤菌就是一个小小的氮肥工厂,把空气中的氮固定在土壤里,玉米可以随时吸收营养,茁壮生长,它们生活在一起,没有斗争,成了亲密的好"邻居".棉花、小麦的根系分泌物能促进豆科植物根瘤菌的生长,所以种植棉麦以后,土地轮种豆科植物为好.大麻根系分泌物对马铃薯免疫病有一定的预防作用,马铃薯如果和洋葱间作,马铃薯的免疫病也会大大减轻.     

植物根——化学工厂

根作为植物地下部分的组织,其功能不被肉眼所见,即使许多生态学家,也未意识到根对植物的特有重要性。一般认为,根有机械支撑和吸收水分和矿物质的作用,由于根与土壤中的多种微生物群落有关,它们间已形成了复杂的共生关系,如豆科植物的根瘤菌和菌根的关系,然而,人们对根的化学     

根瘤菌-豆科植物共生体系在重金属污染环境修复中的应用

指出了生物修复以其操作简便、成本低廉及安全性高等优点被当作修复重金属污染环境的有效途径。根瘤菌-豆科植物共生体系是一种固氮能力较强的体系,在改善土壤氮素不足中起到了关键作用。阐述了根瘤菌-豆科植物共生体系在重金属污染环境修复中应用。     

菌根菌与根瘤菌对新银合欢苗接种效应研究

菌根化是某些树种育苗、造林成功的关键和提高苗木生物产量的必要措施。不少国家已将其列为林木速生丰产的一项常规技术,最近又有苗木菌根化是造林三要素的提法。新银合欢属豆科植物,而豆科植物本身是内生菌根,根瘤菌对促进豆科植物的生长具有特殊的作用.为了探索菌根和根瘤对新银合欢的生长影响.近年来我们采用内生菌根和根瘤菌对新银合欢苗木接种试验。结     

木本豆科植物根瘤菌16S rDNA的PCR-RFLP研究

为了研究华东地区木本豆科植物根瘤菌种质资源的遗传多样性,采用6种限制性内切酶对53株根瘤菌进行16S rDNAPCR-RFLP多态性分析,共产生35种类型的16S rDNA遗传图谱.聚类分析结果表明,在75%的相似水平上,所有供试菌株可以分为8个系统发育分支.其中,分支3由22个菌株组成,属于中慢生根瘤菌属(Meso-rhizobiura);9个菌株组成分支6和7,属于快生根瘤菌属(Rhizobium);分支5包含7个菌株,属于慢生根瘤菌属(Bradyrhizobium);其余19个菌株与已知菌株亲缘关系较远,可分为4个未知的系统发育分支,这4个新的分支最少有1个新的根瘤菌属存在.结果还表明木本植物根瘤菌存在着极丰富的遗传多样性.     

热带主要树种菌根根瘤调查初报

前言微生物和植物有各种共生关系,这对植物生长是很重要的。豆目植物直接受共生根瘤菌的影响,使之无需依赖土壤氮素的供应而生长。许多树木的生长常依靠其根部形成菌根的真菌,扩大吸收表面积,从中吸取更多的水分和矿质营养,转化土壤有机质,提高土壤有效肥力,以供应共生树木的需要。与豆目植物共生的根瘤菌或与非豆目植物共生的放线菌,可在     

豆科树种根瘤菌与四种豆科植物的接种试验

从５１种豆科树种根瘤中分离获得的６６个菌株与４种豆科植物进行接种试验，幼苗经５０ｄ培养，刺槐，合欢，大豆，豌豆的结瘤率分别为１００％，８７．９％，６９．７％，２５．８％。其中有１２个菌株可同时在这４种豆科植物上结瘤，２９个菌株可同时在刺槐，合欢和大豆上结瘤，４个可同时在刺槐，合欢和豌豆上结瘤，说明豆科对种根瘤菌具有较广泛的共生寄主范围。     

Endohyphal bacteria from fungal endophytes of the Mediterranean cypress (Cupressus sempervirens) exhibit in vitro bioactivity

Endohyphal organisms of endophytic fungi can induce, or promote, beneficial effects of their respective host fungi to the host plant that harbours them. The Cupressaceae plant family (Coniferales) hosts highly bioactive endophytic fungi. Here, we show that a fraction of such endophytic fungi harbours bioactive endohyphal bacteria with a non‐obligatory symbiotic lifestyle. Indeed, 5 of 16 (31.25%) endophytic fungi of Cupressus sempervirens harboured endofungal bacterial strains of Bacillaceae (G⁺, Bacilli) and Sphingomonadaceae (G^?, α‐Proteobacteria), that is Bacillus pumilus (from the fungi Leptosphaeria CSE₂₁₁ and Pyrenochaeta CSE₁₃₄), Bacillus subtilis (from the fungi Leptosphaeria CSE₂₁₂ and Ascorhizoctonia CSE₁₄₈) and Sphingomonas paucimobilis (from the fungus Ascorhizoctonia CSE₁₉₅). Notably, each endophytic fungal species contained only one endofungal bacterial species that was stably maintained in symbiosis over several rounds of subculturing. Moreover, we investigated whether cypress endofungal bacteria (CEB) could benefit their host fungus competing with other fungi and bacteria or the host plant against the invading microorganisms. In vitro assays indicated that CEB possessed antagonistic activity against cypress endophytic and pathogenic microbiome. Also, CEB metabolites and volatile compounds (VOCs) exhibited antifungal and antibacterial activity against the target microbiome. Bioactivity of CEB was less than that of the endophytic microbiome of Cupressaceae, on which we reported earlier. In conclusion, our work is the first to document endohyphal bacteria of fungal endophytes of C. sempervirens and the bioactivity of such endohyphal symbionts. These findings implicate a complicated interrelationship among host plant, endophytic microbiome and endofungal bacteria, which might be of high importance for evolutionary, as well as environmental and agricultural studies. Eventually, endohyphal bacteria may be introduced as a novel source for lead molecule discovery.     

Effect of rhizobial inoculation on growth of <Emphasis Type="Italic">Calliandra</Emphasis> tree species under nursery conditions

A nursery experiment was conducted in un-sterilized soil in Senegal using six Calliandra species or provenances inoculated with a mixture of seven rhizobial strains. Plant growth was assessed periodically at 1, 2, 3, 12 and 18 months whereas nodulation, shoot and root dry weights were assessed at 12 and 18 months after planting (MAP). Un-inoculated seedlings of all the six species died at 12 months after planting. Results of growth assessments were variable with significant differences (P < 0.05) between C. calothyrsus Meissn provenances (Flores and San Ramón) and C. juzepczukii Standley in height at 1, 2 and 3 MAP. Shoot dry weights of San Ramón provenance of C. calothyrsus Meissn were also significantly different from those of C. acapulcensis (Britton and Rose) Standley and C. longepedicellata (Mc Vaugh) H. Hern and Macqueen at 18 MAP. In contrast, C. glandiflora (L’Her.) Benth grew poorly and did not nodulate. Although rhizobial inoculation improved shoot and root dry weights some differences were observed among the Calliandra species in response to the inoculation, which suggested the occurrence of interaction between the rhizobial strains and the host plant species tested.     

银合欢根瘤细胞的超微结构

银合欢是热带豆科固氮树种,已引起世界各国的普遍重视。我国大陆沿海亚热带地区已有60—70年的引种史。在过去引种栽培的基础上,80年代由国际固氮树种协会(NFTA)和麦威夷大学提供我们一批新银合欢种籽。厦门引种栽培的银合欢,与在其它热带地区有同样表现,速生快长、结果荚早、种籽成熟弹出,就地萌发丛生,压倒附近的其它植物。它的根系生长十分发达。幼苗期就结瘤很多,根瘤直径2.5—15mm,呈现不同形状的复式分叉瘤。测出固氮活性8.069—12.207βmC_2H_4·g~(-1)鲜瘤·时~(-1)。另外植株各部分蛋白质含量丰富,其中还含有一种特殊的氨基酸,与其固氮细胞累积转运有着密切关系。本文仅介绍银合欢根瘤细胞结构变化特征,和与其它豆科根瘤的比较进行了讨论。     

利用中药重楼内生菌解决其药用资源紧缺的研究前景

中药重楼化学成分复杂,药理活性强,临床应用范围广,是"云南白药"等多种中成药的主要原料之一.由于重楼生长周期长、价格居高不下,加之对该药狂采滥挖,重楼已成国家重点保护的濒危物种,该资源的有效保护和合理利用势在必行.药用植物内生菌次生代谢产物的测定结果证实了内生菌能够产生与宿主植物相同或相似的药用活性成分,中药内生菌资源...     

Effects of vegetation coverage on oviposition by <Emphasis Type="Italic">Luehdorfia japonica</Emphasis> (Lepidoptera: Papilionidae)

The effects of canopy and shrub layer coverage on the frequency of oviposition by a papilionid butterfly, Luehdorfia japonica, were investigated. Density of larval host plant tended to be higher where shrub layer was thinner, and the frequency of oviposition was correlated with host plant abundance. On the other hand, host plant abundance and the frequency of oviposition were not correlated with canopy layer coverage. Eggs were mainly found at or near the forest edge irrespective of host plant abundance.     

紫胶虫、白蜡虫、倍蚜虫主要寄主植物种类研究

紫胶虫 (ｌａｃｉｎｓｅｃｔ)、白蜡虫 (ｗａｘｓｃａｌｅ)、倍蚜虫 (ｇａｌｌａｐｈｉｄｓ)是我国重要的资源昆虫。资源昆虫的寄主植物不仅是它们的栖息和繁衍场所 ,更是其食物来源。寄主植物种类繁多 ,其中不乏优良寄主植物物种。通过在紫胶、白蜡、五倍子的主产区广泛收集紫胶虫、白蜡虫、倍蚜虫的寄主植物物种资源 ,在南亚热带的云南景东进行繁殖 ,用迁地保存的方式保存于景东试验站树木园内。多年来 ,已收集、保存了紫胶虫、白蜡虫、倍蚜虫的寄主植物 2 0 0余种 ,隶属 36科 98属。本研究于 1 993年至 1 999年立题进行 ,现将主要结果报…     

Foliar fungal pathogens of European woody plants in Siberia: an early warning of potential threats?

In this article, we report observations made during thirteen years on foliar fungal pathogens attacking European and Eurasian woody broadleaved species in Siberian arboreta and cities and discuss the possibility of using such data for detecting exotic pathogens that may represent a danger for European tree and shrub species, should these pathogens be introduced into Europe. A total of 102 cases of symptomatic infections (fungus‐host plant associations) involving 67 fungal species were recorded on 50 of the 52 European and Eurasian woody plant species. All but four of the fungi found during the surveys were previously reported in Europe. However, 29 fungus–host plant associations are apparently new to science, suggesting that complexes of cryptic species differing in their host range and geographic range may occur. Seventeen percentage of associations were given a high damage score, that is, more than 50% of plant area was attacked, for at least some localities. In nearly half of the cases, fungus–host plant associations were found to be very frequent, that is, occurring every year and at all locations where the plant was inspected. A list of pathogen–host associations in Siberia deserving further investigation is provided, either because the pathogen is not yet recorded in Europe or because the pathogen–host association has not yet been reported, and the damage is high or, finally, because the damage and infestation level is unusually high in known associations. Further studies should involve molecular characterization of these foliar pathogens and their host range testing.     

青枯菌对植物的致病机制及其调节

青枯菌引起许多植物及林木青枯病。该菌侵染植物根部,首先在根皮层细胞间隙等处定殖,然后入侵维管束,在木质部导管内扩展危害;细菌在导管及相邻组织内迅猛增殖和广泛散布,由此产生输水管道的阻塞和破坏并最终导致植物枯萎。胞外多糖(EPSI)、细胞壁分解酶(主要是果胶质酶和纤维素酶)、Ⅲ型Hrp分泌系统产物是主要的致病因子,其中EPSI尤为突出,它在保护细菌、促进细菌移动和定殖以及堵塞和破坏寄主导管方面都起着重要作用。而上述致病因子的协调作用则由一复杂的调节系统控制,这一系统由随细菌密度变化而变化的3 -羟基棕榈酸甲基酯水平作为信号,以PhcA调节基因的启动和转录为核心,自动而精密地调节病菌有关致病基因的表达及关闭,并由此控制细菌的生长状态。     

拮抗菌株XZQ-20的鉴定及对多种植物病原细菌的拮抗 活性分析

利用拮抗微生物不仅能有效防治植物病原细菌，而且对环境友好。该研究中，拮抗菌株 XZQ- 20 分离自健康杨树根际土壤，基于形态学特征、生理生化特性和 16S rDNA 序列分析将该菌株鉴定为 深层类芽孢杆菌（Paenibacillus profundus），XZQ-20 具有蛋白酶活性，其对 4 种植物病原细菌欧美杨细 菌性溃疡病菌（Lonsdalea quercina）、丁香假单胞菌（Pseudomonas syringae）、软腐欧文氏菌（Erwinia carotovora）和核桃黄极毛杆菌（Xanthomonas juglandis）均具有较强的拮抗活性，抑菌圈大小分别 为（11.75±1.06）mm、（13.3±2.26）mm、（16.75±0.07）mm 和（7.55±1.06）mm。 此 外， 对 拮 抗 菌 株 XZQ-20 的无菌培养滤液的拮抗活性进行测定，发现其无菌培养滤液也表现出了较强的拮抗活性，对 4 种植物病原细菌的抑菌圈直径分别达到（8.18±0.75）mm、（7.63±0.88）mm、（8.03±0.93）mm 和 （8.60±0.53）mm。研究结果表明拮抗菌株 XZQ-20 可用作为潜在的高效防治植物病原细菌的生防制剂。