核盘菌属一新种——人参核盘菌

本文报道了采自人参(Panax ginseng C. A．Mey (保留名nom. Coiiscry))的核盘菌属一新种——人参核盘菌(Sclerotinla．Ginseng Wang C. R.,C. F. Chen et J. Chen)。该种在形态学以及可溶性蛋白、果胶(甲)酯酶和多聚半乳糖醛酸酶谱带等方面,均不同于已知种核盘菌(S. sclerotiorum (Lib．)de Bary),小核盘菌(S. minor Jagger)车轴草核盘菌(S．Trifoliorum Erikss．)和细辛核盘菌(S．Asari Wu et C．R. Wang)。模式标本(800719)保存于沈阳农业大学植物免疫研究室。     

VERTICILLIUM WILT OF BRUSSELS SPROUT

A wilt disease of Brussels-sprout plants caused by Verticillium dahliae Kleb, is described. Field observations indicate that the disease is more severe in a wet than in a dry season, the various stages of the pathological symptoms appearing earlier and developing more rapidly. This was corroborated by experiment; under dry conditions the onset of wilt symptoms was delayed and the severity of attack diminished. Since nine different strains and/or species of Verticillium wound-inoculated into Brussels sprouts failed to induce wilt, and since the isolate from this host proved to be non-pathogenic to a wide range of plants usually susceptible to attack by Verticillium spp., it is suggested that the V. dahliae from Brussels sprouts is a distinct physiological strain. Variations in the amounts of the different chemical constituents of the soil (calcium, nitrogen from two different sources, phosphate and potassium) have no apparent effect upon the incidence of disease. The pathogen is not seed-borne but it may be spread by the dissemination of infected plant tissues. Some control measures are suggested and farmers are advised to grow in the infected soil runner beans, cauliflower and broccoli which are resistant to attack by this fungus.     

核盘菌可溶性蛋白质及同工酶电泳研究*

为了研究核盘菌的分类和生理分化问题,对供试的28个核盘菌株进行了可溶性蛋白质,芳香基酯酶和酸性磷酸酯酶同工酶电泳谱带以及紫外光吸收峰图形的试验研究,其结果,可分为五种类型。其中属于核盘菌属有四个种,即核盘菌Sclerotinia sclerotiorum(Lib.)de Bary(=Whetzelinia sclerotiorum(Lib.)Korf & Dumont),三叶草核盘菌S.trifoliorum Erikss.,细辛核盘菌(S.asari Wu et C.R.Wang和人参菌核病菌Sclerotinia sp。人参菌核病的另一分离菌和油菜菌核病的一个分离菌其谱带与灰葡萄孢(Botrytis cinerea)谱带相似,应归属于与葡萄孢属(Botrytis)相应的核盘菌。在核盘菌S.sclerotiorum种群中,南方菌系与北方菌系的可溶性蛋白质稍有差异,芳香基酯酶和酸性磷酸酯酶活性强度也稍有不同,可能存在生理分化现象。     

WILT OF LUCERNE CAUSED BY SPECIES OF VERTICILLIUM

The incidence and symptoms of a disease of lucerne induced by Verticillium spp. are much less severe immediately after the crop has been first cut than later when the crop has matured. Infection becomes more marked as the season advances and the age of the ley increases, and cuts taken in the third harvest year are proving unprofitable.
In cross-inoculation studies the causal organisms of lucerne wilt, V. albo-atrum and V. dahliae prove to be only mild pathogens to hop, potato, tomato and antirrhinum, and are not pathogenic to sainfoin and clover. The last two may therefore be cultivated as fodder crops in those areas most severely affected by lucerne wilt, but the cultivation of potatoes after lucerne should be discouraged, particularly if lucerne is to be sown in future years, since the potatoes might build up a reservoir of inoculum of the lucerne pathogen. In studies of host-parasite relations it is shown that V. albo-atrum and V. dahliae from lucerne, V. albo-atrum from hop, V. tricorpus from tomato and V. nigrescens and V. nubilum from potato vary in their effects upon lucerne seedlings growing on agar media, V. albo-atrum from lucerne being, as in the field, the most virulent and the only one to reach the xylem vessels under the conditions of the experiments.
The dressings Agrosan-GN (containing mercury) and Fernasan (containing thiram) are toxic both to spores of Verticillium on lucerne seed coats and to infected plant material carried with seed, and although they are also toxic in vitro to Rhizobium mellelotus this did not prevent dressed seeds which had been inoculated with the bacterium from developing into healthy seedlings bearing normal root-nodules.     

核盘菌可溶性蛋白质及同工酶电泳研究

为了研究核盘菌的分类和生理分化问题,对供试的28个核盘菌株进行了可溶性蛋白质,芳香基酯酶和酸性磷酸酯酶同工酶电泳谱带以及紫外光吸收峰图形的试验研究,其结果,可分为五种类型。其中属于核盘菌属有四个种,即核盘菌Sclerotinia sclerotiorum(Lib.)de Bary(=Whetzelinia sclerotiorum(Lib.)Korf & Dumont),三叶草核盘菌S.trifoliorum Erikss.,细辛核盘菌(S.asari Wu et C.R.Wang和人参菌核病菌Sclerotinia sp。人参菌核病的另一分离菌和油菜菌核病的一个分离菌其谱带与灰葡萄孢(Botrytis cinerea)谱带相似,应归属于与葡萄孢属(Botrytis)相应的核盘菌。在核盘菌S.sclerotiorum种群中,南方菌系与北方菌系的可溶性蛋白质稍有差异,芳香基酯酶和酸性磷酸酯酶活性强度也稍有不同,可能存在生理分化现象。     

THE CONFIRMATION OF THE VARIETY FABAE KEAY OF SCLEROTINIA TRIFOLIORUM ERIKSSON

There is confusion as to whether the Sclerotinia on Vicia faba is a normal strain of Sclerotinia trifoliorum as found on clover and related legumes or a distinct variety (var. fabae ). Pathologically the two fungi appear to be the same, and field observations indicate that beans in the rotation may aggravate the incidence of clover rot. A re-investigation of the morphology of the two fungi is made to assess the status of var. fabae.
The two fungi could not be distinguished by apothecial characters or cultural behaviour. Ascospore measurements confirm the existence of S. trifoliorum var. fabae , although 5. trifoliorum proper also occurs on beans. Var. fabae has not been found on any legume besides beans. Isolates from trefoil and sainfoin agree in spore size with S. trifoliorum on clover.
When isolates of S. trifoliorum are co-inoculated on the same Petri plate, they either do not react, or react to form a 'demarcation line'. Although a demarcation line is assumed to imply a genetic difference, non-reaction does not necessarily imply genetic identity. Non-reaction and the formation of a demarcation line also occur when var. fabae strains are co-inoculated together. When an isolate of S. trifoliorum is co-inoculated with an isolate of S. trifoliorum var. fabae an 'incompatibility line' is formed. Use can be made of this fact in identification.
On the basis of co-inoculations 5. trifoliorum and S. trifoliorum var. fabae are both shown to constitute a diverse range of biotypes. Segregation of biotypes in the ascus as a result of heterokaryosis in the ascus-initial is demonstrated. The view is expressed that heterokaryosis is the mechanism underlying the production of new biotypes.     

WILT OF LUCERNE CAUSED BY SPECIES OF VERTICILLIUM

A wilt disease of lucerne caused by species of Verticillium is described: at twenty-eight disease areas in England and Wales the pathogen was V. albo-atrum , while at one site it was V. dahliae . Both pathogens form superficial conidia on the basal regions of infected stems. It is shown that V. albo-atrum is introduced into a new area in contaminated plant material harvested with the seed from an infected crop. Rapid secondary spread of the disease follows the dissemination of spores from infected stems, and by contact of these and transported fragments of diseased tissues with the wounded surfaces of recently cut lucerne plants. It is recommended that seed should be collected only from healthy crops and that machinery, footwear, etc. should be disinfected before leaving a site of infection.
Manurial trials showed that the incidence of wilt induced by V. albo-atrum was very severe under all soil conditions tested, whereas V. dahliae is a virulent pathogen only to plants in soil rich in superphosphate. Generally the more vigorous the growth of the lucerne–in soils rich in potash and hoof and horn–the more rapid is both the onset of wilt and the resulting secondary spread of the disease throughout the crop.     

VASCULAR DYSFUNCTION IN FUSARIUM WILT OF TOMATO

Leaves on tomato plants infected with Fusarium oxysporum f. lycopersici frequently wilt unilaterally when the vascular bundles supplying the affected leaflets are diseased. However, when the vascular bundles on one side of healthy petioles are severed by notching the petiole base, the entire leaf remains turgid. Leaflets on the notched side receive water by diffusion between bundles at the petiole tip. Lateral translocation of water out of individual vessels and between bundles in diseased xylem is impaired by the impregnation of vessel walls, intercellular spaces, and cells adjacent to vessels with the products of vascular discoloration. Waterproofing of vascular bundles can be induced in excised healthy leaves by culture filtrates of the pathogen and catechol. Waterproofing of vessels may play an important role in vascular dysfunction by confining water to individual vessels and thereby increasing the importance of vessel occlusions.     

油菜菌核病菌生理生态研究

通过试验分析,结果得出,油菜菌核病菌生长温度范围在0～34℃之间,23℃以下菌丝生长速度与温度呈正相关,25℃以上则呈负相关,23～25℃最适宜,菌丝和菌核致死温度分别为45℃和75℃．该菌对酸碱度适应范围很广,PH1～14范围内只在PH_1条件下不能生长,其最适PH值为5～6。病菌利用铵态氮源能力最强,硝态氮源次之,不能利用亚硝态氮;对氨基酸利用能力以精氨酸最强,其次是酪氨酸、天门冬氨酸和谷氨酸,赖氨酸最差。植株内精氨酸和赖氨酸比值大的白菜型油菜“黄鳝籽”病情扩展最快。     

SOME SOIL FACTORS AFFECTING VERTICILLIUM WILT OF ANTIRRHINUM

Variations in the application rates of chalk and superphosphate and the omission of all the fertilisers had no visible effect on the incidence of wilt caused by any of the five Verticillium species.
he literature dealing with the influence of soil conditions upon the Verticillium wilt of a wide range of host plants is reviewed. It is shown that the species V. alboatrum, V. dahliae, V. nigrescens, V. nubilum and V. tricorpus vary inter se in their pathogenicity to Antirrhinum majus, and that their infectivity may be influenced by soil treatments. Thus, in pot cultures, the incidence of antirrhinum wilt induced by Verticillium dahliae and V. nigrescens was reduced by increasing sulphate of potash or ammonium sulphate; or by decreasing soil moisture. Very wet soil and heavy dressings of hoof-and-horn were the only conditions under which V. nubilunt and V. tricorpus induced wilt symptoms. Z7. albo-atrunt was the most virulent species tested; none of the soil treatments decreased its pathogenicity.     

PHYSIOLOGICAL STUDIES ON THE VERTICILLIUM WILT DISEASE OF TOMATO

The water loss per unit leaf area of tomato plants was decreased after inoculation with Verticillium albo-atrum. When diseased plants began to wilt water loss temporarily increased, but then rapidly decreased to become less than that of healthy plants grown under conditions of adequate or restricted water supply.
The transpiration of excised leaves from plants grown with a restricted water supply was reduced, but not so severely as that of comparable leaves from infected plants. Water loss from leaves on infected plants was reduced irrespective of any blocking of the petiolar xylem.
The rate of water loss from turgid leaf disks on mannitol solutions, and the rate of water uptake of leaf disks on water was similar for disks cut from wilting or turgid leaves of diseased plants or healthy plants grown with an adequate or restricted water supply.
Disease or poor water supply reduced leaf growth but had no effect on the rate of leaf initiation. Although the density of stomata was higher on leaves of diseased plants the stomatal area was less than on healthy plants.
The resistance to water flow in diseased stems was high and was correlated with vessel blockage. About half the blocked vessels contained hyphae. The severity and localization of symptoms in inoculated plants growing on susceptible or resistant rootstocks was directly related to the extent of invasion by the pathogen and to vessel blockage.
Experiments on the wilting activity of cell-free filtrates from cultures of the pathogen in vitro indicated that it produced a stable substance, not an enzyme, that caused wilting in cut shoots by blocking the end of the stem. It is suggested that an increasing internal water shortage causes major symptoms of disease.     

核盘菌弱毒株Ep-1PN培养性状的有性遗传特性*

观察和测定了核盘菌（Sclerotiniasclerotiorum（Lib．）deBary）弱毒株Ep-1PN单孢分离物的生长、菌落扩展和菌落形态等培养性状。结果发现：来自7个子囊盘的1574个单孢分离物中有1560个分离物的培养性状与正常菌株的没有显著差异,与亲本相似的分离物只有6个,其它8个分离物介于弱毒株Ep-1PN与正常菌株之间。弱毒株Ep-1PN培养性状的有性遗传不遵循孟德尔核遗传规律。     

油菜菌核病病斑扩展的动态模型

油菜菌核病主茎上病斑长度和面积的扩展与时间间的关系极相关,同一植株上、下部病斑扩展动态无明显差异,中、高两种肥力条件对主茎同一部位病斑扩展动态无明显影响,相对较低的湿度与病斑扩展相关不显著．