青枯假单胞杆菌对木麻黄致病机理的初步研究

通过用病原悬浮液及培养滤液等对木麻黄元根苗和有根苗进行接种处理，发现青枯菌Ｐｓｅｕｄｏｍｏｎａｓ ｓｏｌｏｎａｃｅｚａｒｕｍ Ｅ．Ｆ．Ｓｍｉｔｈ培养滤波对木麻黄具有强烈的致萎作用。小苗枯萎主要是由滤液中毒性物质诱导植物产生填充体堵塞民管所致细菌培养滤液中毒性物质对热稳定，在ｐＨ－４－１０的范围内毒性不受影响、而且能够致萎多种针阔叶树种小枝，个有非特异性。     

榉树枯萎病菌毒素的提取及生物活性的测定

为了明确榉树枯萎病菌毒素的致病能力,对榉树枯萎病菌毒素进行了提取及生物活性的测定。结果表明:病原菌毒素滤液的生物活性主要体现在对于榉树胚根生长的抑制作用以及对于榉树幼苗的致萎性。通过对培养液种类、培养温度、培养时间、培养方式、培养环境酸碱度以及光照与否6项指标进行筛选,最终确定使用改良Czapek培养液,在25℃下,持续光照,连续振荡,p H为7的条件下可以获得较多的毒素。毒素对榉树的胚根生长存在明显的抑制作用,毒素的浓度越高,抑制作用就越明显。不同浓度的毒素滤液处理对榉树幼苗的致萎作用不同,浓度越高致萎性也越强。     

肉桂枝枯病菌毒素的研究

本文是对肉桂枝枯病病原菌毒素研究的首例报道。生物活性测定显示，病菌知液体培养基中可产生导致内桂嫩梢萎蔫和叶盘褐变坏死的致病毒素。改良Fries液体培养基振荡培养和PD液体培养基青止培养为较好的产毒培养方式。病原菌毒素为非寄主专化性毒素，除肉桂外，还对香樟、马尾松、薇苷菊、卤地菊和番茄等植物具有致萎活性，毒素为弱酸性（pH5.4），对冷、热稳定性强，极性较大，易深于水、乙醇、丙酮、正丁醇＋丙桐及乙酸乙酯，部分溶于氯仿，基本不溶于乙醚。研究表明毒素为非蛋白质、多糖及核酸类大分子物质。含毒滤液可能含有糖醛类物质，其致毒活性经乙醇和丙酮纯化后有所增强，经HPLC分离出的组分I可能为毒性成份。肉桂叶盘经毒素处理后，其相对电导率较对照大幅度增加，感病的本地桂比抗病的大叶青化桂增加更为明显。     

松材线虫携带的一株荧光假单胞细菌致萎毒素的初步分离

用荧光染色显微生测法检测液体培养基的无细胞滤液毒性,研究从松材线虫虫体上分离鉴定的荧光假单胞GcM5-1A菌株在寄主体外培养的产毒现象.结果表明:GcM5-1A液体培养的无细胞滤液对黑松细胞的毒性随培养天数增加而增强,培养到第4天时,无细胞滤液的毒性开始进入相对稳定期.因此,在进行该菌株毒素的分离鉴定工作中,可将4 d作为其培养时间.使用DM-36透析膜对培养4 d的GcM5-1A无细胞滤液透析后的毒性测定结果显示:其膜内和膜外组分生测毒性分别与对照培养基的无细胞滤液毒性之间的t检验差异显著,证明其透析膜内、膜外组分均有毒性.该结果表明:GcM5-1A菌株的毒素不是单一化合物,而是由比较多的物质组成,其中含有大分子物质,如蛋白质、多肽、酶等;也有小分子有机化合物.     

影响木麻黄青枯病抗性测定的几项因素的研究

木麻黄无性系对青枯假单胞杆菌的抗病性测试受到植物材料、接种条件及病级测定三方面因素的影响。研究表明在无根苗与有根苗上病害的发生具有一致性特征，并且与高度相关，但无根苗更为感病。在三种龄期的无根苗中，以木质化的褐梗最为感病，绿梗次之，嫩枝较为抗病。青枯菌在连续培养１４天后接种致病力不减。病害的相对强度在直射光、散射光及灯光等三种光照条件下无明显区别。病害强度随着接种浓度的增加而增高，但当达到一定程度后便趋缓。研究认为在室内以中等浓度的青枯菌液接种木麻黄无根褐梗苗是快速测定其抗性的一个可靠方法，并就采用相对病害强度代替发病株率作为病级指标等问题进行了讨论。     

木麻黄害虫星天牛生活习性及防治

木麻黄害虫星天牛生活习性及防治＊徐起关键词木麻黄星天牛生活习性防治近年来，浙江省沿海防护林的主栽树种——木麻黄（ＣａｓｕａｒｉｎａｅｑｕｉｓｅｔｉｆｏｌｉａＬ．）受星天牛（ＡｎｏｐｌｏｐｈｏｒａｃｈｉｎｅｎｓｉｓＦｏｒｓｔｅｒ）危害日益严重。据作者对...     

松材线虫病感病松树中致萎毒性物质的研究

本研究用我国自然感染松材线虫病的15年生以上黑松和马尾松以及人工感染松材线虫病的3年生黑松的木质组织进行萃以和粗提纯，方法为高压蒸煮法和氯仿碱法。生物测定结果显示，有致萎活性的毒性物质仅存在于自然感病未死的黑松和马尾松以及人工感病未死的黑松木质组织中。自然感病死后1年的黑松和马尾松以及健康松树不中含有这些毒性物质。通过气相色谱－质谱联用仪（GC／MS System）对上述木质组织萃取物作定性分析发现，自然感病未死的黑松、马尾松和人工感病未死的黑松有致萎活性的萃取物中均含苯乙酸和2－甲氧基肉桂酸，自然感病死后1年的松树和健康松树中则无。而在健康松树和感病松树中都发现有苯甲醛存在。表明毒性物质与苯乙酸和2－甲氧基肉桂酸有关，苯甲醛则是松树正常的代谢产物。苯乙酸和2－甲氧基肉桂酸均为酚类化合物，是植物体内重要的次生物质。说明感病松树中的毒性物质是松树组织由于松材线虫侵染而产生的异常代谢产物，应称之为致萎毒性物质。     

新造防护林带前沿短枝木麻黄死因分析

１９９６年１２月，对汕头保税区沿海木麻黄（ＣａｓｕａｒｉｎａｅｑｕｉｓｅｔｉｆｏｌｉａＦｏｒｓｔ．＆ｆｏｒｓｔ）防护林带枯死的原因进行了调查分析。认为木麻黄死亡的主导因子是其枝、干、根的盐分含量过高所致。立地的变化，常年风大，蒸发量大于降水量也是使木麻黄枯死的因素。同时对防护林带幼林期加强管护措施提出了建议。     

木麻黄根瘤内生菌分离培养和宿主范围的研究

从普通木麻黄、细枝木麻黄和粗枝木麻黄根瘤上分离到具典型孢囊和泡囊特征的放线菌Ｆｒａｎｋｉａｓｐ．菌株１８株,均获得纯培养。ＢＡＰ是木麻黄根瘤内生菌生长的适宜培养基。同一木麻黄根瘤中有不同形态特征与侵染特性的内生菌共存;木麻黄根瘤内生菌在木麻黄不同种内可交叉侵染,还可侵染杨梅、四川木岂木。     

寄生真菌对根结线虫的致病力评价

用南方根结线虫卵作接种试验,证明从根结线虫成虫及卵上分离７６个菌株中大部分菌株有寄生能力,种间及株间寄生率差异明显,表明这种方法是检验寄生真菌寄生能力的一种良好方法。通过测定,７６个菌株中有１０个菌株对南方根结线虫卵的寄生率超过５０％,种间及菌株间对卵的寄生能力存在很大差异;Ｐａｅｃｉｌｏｍｙｃｅｓｌｉｌａｃｉｎｕｓ,Ｖｅｒｔｉｃｉｌｉｕｍｃｈｌａｍｙｄｏｓｐｏｒｉｕｍ及Ｖ．ｌａｍｅｌｉｃｏｌａ对Ｍｅｌｏｉｄｏｇｙｎｅｉｎｃｏｇｎｉｔａ,Ｍ．ａｒｅｎａｒｉａ和Ｍ．ｊａｖａｎｉｃａ卵的寄生能力进行比较,在３种线虫之间没有明显差异,说明这３种真菌对这３种根结线虫有进行防治的可能性。首次研究了寄生真菌培养滤液对根结线虫的作用,发现大多数寄生真菌的代谢产物对幼虫有毒害作用。２８个菌株中２４个的培养滤液对南方根结线虫幼虫有很高的毒性作用,在４ｈ内５６％～１００％幼虫不活动;Ｐ．ｌｉｌａｃｉｎｕｓ菌株５４培养滤液对幼虫作用的时间不同,效果也有很大差异,作用４ｈ,幼虫不活动率为１００％,作用４８ｈ,幼虫死亡率为１００％。在盆栽试验中,证明某些真菌对无菌土栽培的番茄上南方根结线虫有明显的防治效果。其中Ｐ．ｌｉｌａｃｉｎｕｓ     

白僵菌代谢蛋白对松墨天牛毒性生测方法试验

从白僵菌代谢物中提取蛋白类毒素用于防治松墨天牛,以松墨天牛幼虫为试虫,采用饲喂、口服、表皮接触和血腔注射4种生测方法测定了白僵菌蛋白类代谢物提取液的毒性。结果表明,4种生测方法样品均表现一定的毒性,血腔注射生测所表现的毒性最高。通过对4种生测方法的比较分析,表明白僵菌代谢物中毒素物质的毒性采用血腔注射法最容易检测到。     

白僵菌代谢提取物对美国白蛾毒性生测方法的研究

以美国白蛾幼虫为试虫，采用饲喂、口服、表皮接触和血腔注射4种生测方法测定了白僵菌代谢提取液的毒性。结果表明，4种生测方法代谢提取液均表现一定的毒性，血腔注射生测所表现的毒性最高。通过对着4种生测方法的比较分析，建议白僵菌的代谢物中毒素物质的生物测定首先采用血腔注射法生测。     

Toxin production by Rosellinia desmazieresii (Berk. & Br.) Sacc.

Damage symptoms, were expressed on detached shoots of Salix repens within 24 hours of exposure to toxin preparations from culture filtrates of Rosellina desmazieresii. Many of these symptoms, which resembled those observed on diseased plants, could also be obtained in the test system by exposure to cytochalasin E solutions. This toxic compound is produced by R. desmazieresii and may be important in symptom development, since culture filtrate preparations from isolates producing little cytochalasin E induced few symptoms. Toxin preparations from R. desmazieresii induced damage on detached shoots of several woody species, including both hosts and non-hosts of this fungus.     

Biobleaching of unbleached and oxygen-bleached hardwood kraft pulp by culture filtrate containing manganese peroxidase and lignin peroxidase fromPhanerochaete chrysosporium

Unbleached and oxygen-bleached hardwood kraft pulp (UKP and OKP), respectively, were bleached with a culture filtrate containing manganese peroxidase (MnP) and lignin peroxidase (LiP) fromPhanerochaete chrysosporium Burds. The brightness increases of UKP upon biobleaching with the culture filtrate with and without MnSO₄ were the same. The brightness increase of OKP with MnSO₄ decreased to about half that seen without MnSO₄. Changes in the brightness of UKP and OKP by treatment with the culture filtrate were determined. The brightness increased sharply by about eight points during the first 3h. The 3-h treatment was repeated seven times. The brightness increased linearly with the bleaching of UKP. On bleaching of OKP, the brightness increased slowly and stopped at about 78%.Part of this report was presented at the 62nd Pulp and Paper Research Conference of the Japan Tappi, Tokyo, June 1995     

Effects of Ophiostoma ulmi and Ophiostoma novo-ulmi culture filtrates on elm cultures from genotypes with different susceptibility to Dutch elm disease

Cell cultures of callus tissue cultures obtained from four elm genotypes (Ulmus minor; Ulmus minor×Ulmus pumila; [Ulmus carpinifolia×Ulmus glabra] × [Ulmus wallichiana×Ulmus glabra]; and Ulmus pumila), either susceptible or resistant to Dutch elm disease (DED) were exposed to culture filtrates of Ophiostoma ulmi and Ophiostoma novo-ulmi. Elm cells were largely affected by crude culture filtrate incorporated into the media. However, the correlation between ‘in vivo’ cell resistance and growth in the presence of culture filtrate was poor: the effects of fungal media components were greater than that exerted by fungal exotoxins. Therefore, it is concluded that these ‘in vitro’ assays cannot be used to evaluate resistance sources to DED in elms, or to assess specific pathogenicity of fungal isolates.     

Effects of some bacteria (Pseudomonas spp. and Erwinia herbicola) on in vitro growth of Piptoporus betulinus

Summary Bacteria including Pseudomonas putida, Pseudomonas fluorescens biovar I, Pseudomonas fluorescens biovar V, Pseudomonas aureofaciens and Erwinia herbicola were isolated from discoloured zones in birch trunks. Antagonistic effects of these bacteria to growth of Piptoporus betulinus mycelium were tested in vitro, both in dual culture and using bacterial cell‐free culture filtrates. In dual cultures, P. putida was most effective at inhibiting mycelial growth of Piptoporus betulinus. Filtrates of P. putida inhibited growth of P. betulinus mycelium irrespective of filtrate concentration, incubation time of bacteria and timing of recording mycelium growth. The strongest antagonistic effect (inhibition of fungal growth) was observed on a medium containing 80% of sterile filtrate obtained from 15‐day‐old bacterial cultures. The highest stimulating effect on mycelium growth was noted on medium containing 80% filtrate obtained from 7‐day‐old E. herbicola cultures.     

Test ?inhibition de ľactivité cambiale du Peuplier par Hypoxylon mammatum: mise au point et application

Test of inhibition of cambial activity of poplar by H. mammatum: development and application. A test was developed in vitro in order to estimate the inhibition of hosts’cambium by H. mammatum and applied to a large number of poplar clones. Toxicity of the culture filtrate appears to be selective but not necessarily specific.     

Ectomycorrhizal fungi and exogenous auxins influence root and mycorrhiza formation of Scots pine hypocotyl cuttings in vitro

We studied the ability of the ectomycorrhizal (ECM) fungi, Pisolithus tinctorius (Pers.) Coker and Couch and Paxillus involutus (Batsch) Fr. (Strain H), to produce indole-3-acetic acid (IAA) and to affect the formation and growth of roots on Scots pine (Pinus sylvestris L.) hypocotyl cuttings in vitro. Effects of indole-3-butyric acid (IBA) and the auxin transport inhibitor, 2,3,5-triiodobenzoic acid (TIBA), on rooting and the cutting-fungus interaction were also studied. Both fungi produced IAA in the absence of exogenous tryptophan, but the mycelium and culture filtrate of Pisolithus tinctorius contained higher concentrations of free and conjugated IAA than the mycelium and culture filtrate of Paxillus involutus. Inoculation with either fungus or short-term application of culture filtrate of either fungus to the base of hypocotyl cuttings enhanced root formation. Inoculation with either fungus was even more effective in enhancing root formation than treatment of the hypocotyl bases with IBA. Fungal IAA production was not directly correlated with root formation, because rooting was enhanced more by Paxillus involutus than by Pisolithus tinctorius. This suggests that, in addition to IAA, other fungal components play an important role in root formation. Treatment with 5 microM TIBA increased the rooting percentage of non-inoculated cuttings, as well as of cuttings inoculated with Pisolithus tinctorius, perhaps as a result of accumulation of IAA at the cutting base. However, the marked reduction in growth of Pisolithus tinctorius in the presence of TIBA suggests that the effects of TIBA on rooting are complicated and not solely related to IAA metabolism. The high IAA-producer, Pisolithus tinctorius, formed mycorrhizas, and the IBA treatment increased mycorrhizal frequency in this species, whereas TIBA decreased it. Paxillus involutus did not form mycorrhizas, indicating that a low concentration of IAA together with other fungal components were sufficient to stimulate formation and growth of the roots, but not the formation of ECM symbiosis.     

拮抗细菌诱导油茶植株抗炭疽病研究

研究解淀粉芽孢杆菌Bacillus amyloliquefaciens F14和枯草芽孢杆菌Bacillus subtilis Y13,PX发酵液及其去菌液诱导油茶植株对炭疽病Colletotrichum gloeosporioides的抗性。结果表明,3株拮抗菌及其去菌液诱导处理油茶叶片,都能诱导其产生对炭疽病的系统抗性;以枯草芽孢杆菌Y13及其去菌液的诱导效果最大,分别达到70.7%和68.4%。不同浓度拮抗菌诱导效果有显著差异。在一定范围内,诱导效果随菌浓度增加而增强,当菌浓度达108cfu/mL时,诱抗效果最大。Y13发酵液处理3 d就已产生诱导效果,5 d诱导效果最强,可持续20 d以上。