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11.
本试验对捕食线虫性真菌菌种保存技术进行了研究,测定了在不同介质保存条件下,捕食线虫真菌分生孢子和菌丝的存活情况及其不是寄生性线虫的能力.结果表明:在设定的保存条件下,分别经过1周冷冻融化或2周反复冷冻融化,被保存的分生孢子接种于玉米粉琼脂培养基上能生长发育:在加入线虫第3期幼虫后,能生产捕食器,对虫体发挥捕食作用. 相似文献
12.
Leptin对动物繁殖机能的影响及其应用前景 总被引:2,自引:0,他引:2
Leptin是由脂肪组织分泌的一种“厌食”激素。自1995年发现以来,就成为最活跃的研究领域。它可通过下丘脑或直接作用于卵巢,对动物青春期的发育、生殖器官的发育以及性激素的分泌都有重要的调节作用。本文综述了Leptin的生物学特性、作用机理及其在繁殖方面的作用,井指出了它在畜牧生产中应用前景。 相似文献
13.
本文报道了江西三种危害食用菌的绿色霉菌的生物学特性。它们是:绿色木霉(Trichoderma Viride pers exFn)。产黄青霉(Penicillium Chrysoenum Thom)和构巢曲霉(Aspergillus nidulcms(Eidzm)Winter)。 相似文献
14.
本文介绍了万寿菊的形态特征及生物学特性,根据形态特征及生物学特性,探索了万寿菊的育苗技术和栽培技术以及田间管理的方法。 相似文献
15.
16.
本文对天山云杉人工幼林树冠结构以及树冠结构与林木之间的关系进行了研究,并基于生物学原理,在确定有效树冠的法础上,通过决定林木能力的树冠特征对其人林分间伐中的应用进行了初步研究。 相似文献
17.
无公害技术在防治春尺蠖上的应用 总被引:2,自引:0,他引:2
阐述了春尺蠖的危害、发生规律及防治方法。利用糖醋盘 ,灯光诱杀成虫 ,在树干上捆绑草绳 ,喷涂毒环阻止成虫上树产卵及使用无公害生物制剂防治幼虫效果较好 相似文献
18.
Alba Marina Cotes Philippe Lepoivre Jean Semal 《European journal of plant pathology / European Foundation for Plant Pathology》1996,102(5):497-506
An experimental protocol consisting in the colonisation of pregerminated bean seeds dressed withTrichoderma sp. was used in order to study the mechanisms correlated with the protective effect againstPythium splendens. Seed dressed with TH-11 (T. koningii) for 24 h presented a higher protective effect and a higher level of seed colonisation as compared to those dressed with TH-13 (T. longibranchiatum). The levels of seed coat colonisation by TH-11 and TH-13 was shown to be correlated with the carboxymethylcellulase activity, as measured in the seed coats retreived from germinating dressed bean seeds. The seed coat colonisation was also associated with an increased activities of endo-1,3--glucanase and endochitinase measured in seed extracts, and an inhibitory effect of seed extracts onPythium sporangia germination. Pretreatment of TH-13-dressed seeds with a commercial cellulase improved all parameters mentioned above, thus suggesting a role of cellulase activity in the colonisation process and the linked protective effect. The possible role of hydrolytic enzymes in the protective effects is discussed. 相似文献
19.
Y. Robert 《European journal of plant pathology / European Foundation for Plant Pathology》1992,98(Z2):37-45
Conventional ways to control aphid vectors on potato crops rely essentially on cultural and chemical methods. The extensive use of insecticides, too often applied regardless of real needs and consequences, has resulted in more and more failures in both controlling aphids and virus spread. This paper stresses the need to introduce more rationale in the operation of existing methods by improving the efficiency of some of them like forecasting systems, to assess the potential of others like fertilization and semiochemicals and to put most efforts on resistant cultivars so that integrated pest management can be operated in the near future. 相似文献
20.
R. Van Peer A. J. Van Kuik H. Rattink B. Schippers 《European journal of plant pathology / European Foundation for Plant Pathology》1990,96(3):119-132
In carnations grown on rockwool disease incidence of fusarium wilt caused byFusarium oxysporum f.sp.dianthi (Fod) was reduced when Fe-EDDHA instead of Fe-DTPA was used as iron source in the nutrient solution. Addition ofPseudomonas sp. strain WSC417r intensified this reduction in the cultivar Pallas, moderately resistant to Fusarium, but not in the susceptible cultivar Lena. Treatment of plants with Fe-EDDHA instead of Fe-DTPA as iron source resulted in higher numbers and percentages on the roots, ofin vitro antagonistic fluorescent pseudomonads. However, differences were only significant at 56 days after planting for cv. Lena and at 14 and 28 days after planting for cv. Palas. Both chelators, at different concentrations, had no effect on root colonization by eitherPseudomonas sp. strain WCS417r orFod strain WCS816. However, when coinoculated, reduced numbers of propagules ofFusarium were found at concentrations of Fe-EDDHA lower than 10–5 M.Higher concentrations of the siderophore fusarine produced byFod strain WCS816 were demonstrated when Fe-EDDHA instead of Fe-DTPA was used as iron source in culture media. At equal concentrations, no such differences were found in the amount of siderophore produced by WCS417r. Germ tube length ofFod was less with Fe-EDDHA than with Fe-DTPA. The reduction of germ tube length was stronger when the purified siderophore of WCS417r was added in excess to the culture media with Fe-EDDHA than those with Fe-DTPA. Therefore, the observed reduction of germ tube growth can not completely be explained by iron deprivation. It appeared that EDDHA exhibited a toxic effect for conidia ofFod strain WCS816 as well.we conclude that the observed disease reduction by Fe-EDDHA is a consequence of a limitation of iron availability forFod. This limitation is possibly intensified by the increase in number or percentage of antagonistic fluorescent pseudomonads that strongly compete for iron. The additional effect after bacterization withPseudomonas strain WCS417r in Fe-EDDHA treated carnations of cv. Pallas is likely to be due, at least partly, to a direct competition for iron between the siderophores ofFod strain WCS816 and ofPesudomonas sp. strain WCS417r.Samenvatting Verwelkingsziekte in anjers op steenwol, veroorzaakt doorFusarium oxysporum f. sp.dianthi (Fod), werd gereduceerd indien het ijzer-chelaat Fe-EDDHA in plaats van Fe-DTPA werd toegevoegd aan de nutriëntenvloeistof. Bacterisatie metPseudomonas sp. stam WCS417r had een additioneel effect bij de matig resistence cultivar Pallas maar niet bij de vatbare cultivar Lena. Toevoeging van Fe-EDDHA in plaats van Fe-DTPA aan planten als ijzerbron resulteerde op de wortels in hogere aantallen en percentages fluorescerende pseudomonaden, diein vitro antagonistisch waren ten opzichte vanFod. De verschillen waren echter alleen significant 56 dagen na planten voor de cultivar Lena en 14 en 28 dagen na planten voor de cultivar Pallas. Beide chelaten vertoonden bij verschillende concentraties geen effect op de kolonisatie van de wortel door beide microorganismen. Echter, wanneer beide micro-organismen gezamelijk werden toegevoegd nam de wortelkolonisatie doorFod stam WCS816 af bij concentraties lager dan 10–5 M Fe-EDDHA. Er werd meer van het siderofoor fusarine doorFod stam WCS816 geproduceerd bij concentraties lager dan 10–4 M Fe indien Fe-EDDHA in plaats van Fe-DTPA als ijzerbron aan het cultuurmedium was toegevoegd. Er werd geen effect van beide chelaten gevonden op de siderofoorproduktie door WCS417r. Indien een overmaat van het gezuiverde siderofoor van WCS417r werd toegevoegd aan Fe-EDDHA werden een sterkere afname van de kiembuislengte gevonden dan toevoeging aan Fe-DTPA. De reductie van de kiembuislengte bleek niet volledig verklaard te kunnen worden door een afname van de ijzerbeschikbaarheid. Het chelaat EDDHA heeft ook een toxisch effect op conidiën van fusarium.Wij concluderen, dat de waargenomen reductie van de verwelkingziekte door Fe-EDDHA een gevolg is van de afname van de ijzerbeschikbaarheid voorFod. Dit wordt waarschijnlijk versterkt door de ontwikkeling van een antagonistische, fluorescerendePseudomonas-populatie die sterk concurreren om ijzer. Het additioneel effect dat door bacterisatie metPseudomonas sp. WCS417r van de met Fe-EDDHA behandelde matig resistante anjers (Pallas) werd verkregen is voor een deel het gevolg van een directe concurrentie om ijzer tussen de sideroforen vanFod stam WCS816 en vanPseudomonas sp. stam WCS417r. 相似文献