油菜黑胫病菌（Leptosphaeria biglobosa）生物学特性研究

为了解我国油菜黑胫病病原菌（Leptosphaeria biglobosa）的生物学特性,在实验室里研究了温度、pH值、光照、碳源及氮源等条件对该病菌营养生长及分生孢子产生的影响。结果表明：病原菌在5℃～35℃均可进行营养生长并产孢,最适生长和产孢温度为25℃;在pH4～10的范围内该菌均能生长并产孢,在pH7的条件下生长最快,产孢最多。光暗交替有利于菌丝生长和产孢,而持续光照不利于菌丝生长,尤其不利于产孢。最适的碳源、氮源分别是可溶性淀粉、牛肉膏。分生孢子的致死温度为52℃。     

大豆疫霉菌生物学性状的遗传与变异

大豆疫霉菌引起的大豆疫病是大豆上危害严重的毁灭性病害之一.采用经典遗传学方法研究大豆疫霉菌单孢后代的菌丝生长速率、菌落形态、产孢量以及同宗配合性状的遗传变异,以期为有效控制大豆疫病的发展和蔓延奠定基础.结果表明,菌落形态、生长速率和同宗配合性状在单孢后代可稳定遗传,控制上述性状的遗传因子是纯合的;大豆疫霉菌的游动孢子产生能力在单孢后代发生连续性变异,表明这种性状可能是数量遗传性状,也可能控制这种性状的基因为杂合基因或细胞质遗传因子.研究结果初步揭示了大豆疫霉的遗传特征、遗传多样性及多样性产生的遗传学基础.     

球孢白僵菌菌种退化及其对马尾松毛虫防治的影响

球孢白僵菌继代培养中通过菌落局变产生不同类型分离株。本试验检测结果显示此类分离株多表现为产孢量下降、速率增加,毒力降低等与生产性善良爱化类似的变异现象,少数产孢量高,毒力强的分离株,因其生长速率慢即在培养中被掩盖而消失,并据此推断出继代培养次数对该菌退化速率的影响,提出了控制该菌菌种退化的有效措施。     

Breaking seasonal limitation: year-round sporogenesis in the brown alga Laminaria saccharina by blocking the transport of putative sporulation inhibitors

Year-round induction of sporogenesis of Laminaria saccharina was performed by mechanically blocking the transport of the putative sporulation inhibitors produced by the blade meristem and culturing the plants in constant short days. Sporogenesis was successfully induced by removal of the blade meristem, either by cultivating distal blade fragments or by performing a transverse cut in the frond. The earliest sorus formation after artificial induction was 10 days. The age of the sporophytes used for induction was 6–11 months or 2 years in tank-grown or field-collected sporophytes, respectively. Zoospores were successfully released in all cases. Thus, by year-round artificial induction of sporogenesis, (1) sporeling production of L. saccharina and thereafter sporophyte cultivation could be achieved without seasonal limitation, and (2) the life cycle of L. saccharina (from spore to spore) could be completed within 8 months under controlled conditions.     

苹果黑星病潜育期及其病原菌产孢量研究

2002至2004年间,对苹果黑星病潜育期及其病原菌产孢量研究结果表明,苹果黑星病在嘎啦、富士、秦冠3个品种上的潜育期分别为11.1 d、13.2 d、15.7 d;温度对潜育期有很大影响,日平均温度为18℃时,最适宜发病;病菌在3个品种叶片上的产孢量存在显著差异,其产孢量分别为2.8263×104、7.4168×103和1.1465×103孢子/mm2。     

温度对淡紫拟青霉NH-PL-03菌株培养特性及毒力的影响

试验测定了淡紫拟青霉NH-PL-03菌株在不同温度条件(15～35℃)下培养过程中生长特性(OD值、pH值、菌丝干重、孢子量、基质消耗)的变化趋势及对线虫的致死率,系统研究温度对淡紫拟青霉生长的影响,结果表明:温度不仅影响菌体的生长,且影响次生代谢物的毒力。在15～30℃范围内,菌体生长、孢子生成及基质消耗(C、N)速率随温度升高而升高;25℃为菌体生长的最合适温度,培养第5d进入快速增长期,第9d菌丝干重达到1.08g,第10d菌液孢子量达到401.2万个/mL;30℃时总体毒力最高,第7d培养液对茎线虫的致死率达到64.60%,其次是25℃和20℃,最高致死率分别达到56.17%和37.21%;15℃最高致死率仅为24.71%。说明在一定范围内,温度上升有利于毒力产物生成。     

基质浓度对淡紫拟青霉“NH-PL-03”菌株生长的影响

通过测定不同基质浓度(C N=0.001g/mL、0.005g/mL、0.015g/mL、0.045g/mL、0.135g/mL)对淡紫拟青霉“NH-PL-03”菌株生长的影响结果表明,基质浓度对菌体生长有明显影响,基质浓度为0.045g/mL时菌丝生长旺盛,培养10d每瓶干物质量达到0.82g,对茎线虫校正致死率在8d达到峰值52.30%。基质浓度为0.015g/mL的实验组合产孢量最大,培养8d产孢量达峰值69.20百万个/mL。0.135g/mL的基质浓度对菌生长表现出明显抑制作用,培养10d其干物质量和产孢量仅分别为0.23g和15.10百万个/mL。     

新蚜虫疠霉菌株KM0107的产孢量及其对不同蚜虫的毒力

采用孢子浴法测定了新蚜虫疠霉(Pandora neoaphidis)KM0107菌株在RH85%、光周期L:D=12:12、不同温度(15、18、21、25、28℃)条件下的产孢量及其对桃蚜(Myzus persicae)、萝卜蚜[Lipaphis erysimi(Kaltenbach)]、麦长管蚜[Sitobion avenae(Fabrici-us)]、豌豆长管蚜(Macrosiphum pisi)和玉米蚜[Rhopalosiphum maidis(Fitch)]的毒力。结果表明,在28℃条件下菌株KM0107的产孢量最高,培养30 min时产孢量为99.60±4.04孢子。该菌株对桃蚜、萝卜蚜、麦长管蚜、豌豆长管蚜和玉米蚜均具有一定的毒力,在高剂量82.42孢子/mm2的接种剂量下,麦长管蚜、豌豆长管蚜、萝卜蚜、桃蚜和玉米蚜的累积死亡率分别为(92.75±3.54)%、(73.33±4.32)%、(93.75±4.53)%、(98.21±5.46)%、(92.00±5.63)%;致死中分别为(2.3±0.42)、(3.2±0.35)、(2.7±0.35)、(2.6±0.32)、(3.5±0.25)d;接种处理后第7 d致死中量分别为1.61、1.72、1.63、1.53、1.59孢子/mm2。     

稻瘟病菌产孢技术研究

通过比较稻瘟病菌在6种产孢培养基上的生长速度和产孢量,发现米糠培养基是最适宜的稻瘟病菌产孢培养基;在确定米糠培养基为产孢培养基的基础上进行了初步的产孢条件的研究,在每天光照16～24 h,并连续培养5～7 d的条件下产孢量最大。     

Influence of gibberellic acid on the sporulation of Azolla caroliniana, Azolla microphylla and Azolla pinnata

strains used in the study sporulate throughout the year while Azolla caroliniana and Azolla pinnata strains show sporulation only during November–March, the favourable period for sporulation. Application of gibberellic acid (GA) at a concentration of 2.5–100.0 μg ml^–1 substantially enhanced the sporulation frequency and number of sporocarps (mega plus micro) per plant in Azolla microphylla (two strains) during the unfavourable period (September–October) by 77.3–200.0%. The increase in the number of microsporocarps was more than that of the megasporocarps. The sporulation frequency and number of sporocarps in Azolla pinnata (two strains) and Azolla caroliniana during the favourable season also increased considerably due to GA (2.5–10.0 μg ml^–1) application. The optimum GA concentration for the sporulation of the three Azolla species was 2.5 μg ml^–1, which was used in the subsequent investigations. Efficacy of GA for enhancing sporulation was tested across 20 Azolla pinnata strains. A significant positive response was observed in all the strains. Of them, 17 strains for the sporulation frequency and 15 strains for the sporocarp number showed a >25% increase due to GA treatment. Under field conditions, Azolla microphylla (two strains), Azolla caroliniana and Azolla pinnata exhibited 66.0–88.1% higher sporulation frequency and 42.8–52.6% higher sporocarp number due to GA application. However, the proportion of megasporocarps to total sporocarps did not change. Received: 4 August 1998