枯草芽胞杆菌HMB19198菌株抑菌物质的鉴定及其对番茄灰霉病的防治

 设施番茄灰霉病发生频繁,易产生抗药性,利用微生物杀菌剂防治番茄灰霉病是切实可行且对环境友好的措施之一。本研究通过抑菌活性测定和田间棚室试验,获得一株有效防治番茄灰霉病的生防细菌HMB19198,通过16S rDNA联合gyrA、gyrB、rpoB和rpoC等看家基因序列比对将菌株HMB19198鉴定为枯草芽胞杆菌(Bacillus subtilis)。对峙培养结果表明,菌株HMB19198的脂肽提取物对灰霉菌表现较强的抑菌活性,通过色谱分离技术结合质谱分析,证明菌株HMB19198主要产生脂肽类抗生素丰原素(fengycin)和表面活性素surfactin,其中fengycin包含fengycin A(C15-C18)和fengycin C(C19-C20)两种同系物。抑菌活性测定表明,fengycin对灰霉菌表现较强的抑菌活性,显微观察发现,fengycin处理后造成灰霉菌菌丝畸形。通过对菌株HMB19198全基因组序列进行分析,获得fengycin合成酶基因簇,从基因水平证明菌株HMB19198可以产生fengycin。     

北京地区春季大棚番茄灰霉病发生规律分析及预测模型构建

为探索春季大棚番茄灰霉病的发生规律及预测模型的构建,采用定点观察的方法,开展灰霉病发生规律系统监测,并在系统监测基础上构建番茄灰霉病发病程度的预测模型。结果表明,灰霉病的发生大致可分为3个时期,即4月中下旬的快速增长期、5月下旬至6月中旬的稳定增长期和7月上旬以后的缓慢下降期。通过研究番茄灰霉病的发生发展以及温度﹑湿度情况,明确了番茄灰霉病与棚室温度及湿度等环境因子的关系,其与温度呈负相关,与相对湿度呈正相关,并建立了温室大棚中番茄灰霉病流行趋势与温度、湿度间关系的预测模型,该模型具有较高的准确性。     

Outdoor Mold-resistance and Flame Retardance of Pinus massoniana Treated with Nano-ZnO

The effect of nano-ZnO,at concentrations of 2.0,10.0,20.0,and 40.0 g·kg^-1,on mold resistance and flame retardance of Pinus massoniana was studied.Results showed that both drug loading and mold resistance improved as the concentration of nano-ZnO increased with the time to mold initiation for the treated P.massoniana being 3-4 weeks longer than the untreated.The time to ignition（TTI） of P.massoniana treated by nano-ZnO at 2.0 g·kg^-1 was 7 s later than the untreated sample,and the total smoke release（TSR） with 20.0 g·kg^-1 was lower than the untreated.The treated P.massoniana differed slightly from the untreated in heat release rate（HRR）,total heat release（THR）,mass loss rate （MLR）,and effective heat of combustion（EHC）.     

Control of Penicillium expansum with potassium phosphite and heat treatment

Potassium phosphite (Phi) was evaluated for its in vitro activity against Penicillium expansum and for its potential long-term efficacy against postharvest blue mold infections on apple fruit. Phi amended to malt extract agar medium at 2 and 4 mg/ml completely inhibited mycelial growth and conidial germination, respectively. Conidia of P. expansum suspended for 3 min in a solution of 2 mg/ml Phi at 20 °C or heated to 50 °C germinated at 53 and 0%, respectively. Disease incidence of P. expansum on Elstar apples wounded and inoculated with a thiabendazole-resistant isolate was reduced significantly (P = 0.01) following a curative treatment with Phi at 2 mg/ml. When applied on freshly harvested unwounded Elstar apples, Phi (2 mg/ml) reduced blue mold incidence about three-fold compared to the control and was found to be as effective as thiabendazole against natural blue mold infections after six months of storage at 2 °C. Our results suggest that potassium phosphite has a potential to be part of the general management program implemented for the control of postharvest blue mold infections on pome fruits.     

Some factors influencing susceptibility to discoloring fungi and water uptake of Scots pine (Pinus sylvestris), Norway spruce (Picea abies) and Oriental spruce (Picea orientalis)

Abstract

The heartwood and sapwood from Scots pine (PS), Norway spruce (PA), and Oriental spruce (PO) were tested for susceptibility to discoloring fungi and water uptake. In addition, annual ring width and density were measured. The methods used were Mycologg for testing growth of fungi and a modified version of EN 927-5 to investigate water uptake. For pine, the heartwood showed a lower water uptake and no discoloring fungi growing in the tests. The heartwood had a significantly higher density and smaller annual ring width than the sapwood. In PA the heartwood had significantly lower discoloration than sapwood. The total water uptake in g/m² was significantly higher in sapwood, but not the calculated moisture content. As for wood properties, the density was significantly higher in sapwood compared to heartwood, although there were no differences in annual ring width. Regarding PO, differences in water uptake could be seen between sapwood and heartwood although the densities were similar. These results show that susceptibility to discoloring fungi and water uptake is hard to correlate to a single inherent property when looking at different wood species.     

控制稻谷年度积温安全储粮研究

从控制稻谷年度积温出发,通过对稻谷年度积温的研究与控制,探讨了稻谷年度积温与脂肪酸值年度变化量、稻谷年度积温与水分含量、稻谷年度积温与储粮虫霉生长繁殖之间的变化关系,并从中找出规律.说明通过控制储粮年度积温,可以达到降低储粮呼吸强度、抑制虫霉生长,延缓粮食陈化的目的.     

碎段棉秆模具式栽培食用菌配套技术应用研究

将碎段棉秆（〈15cm）经碱化和发酵处理后,用圆柱或长方体模具做成菌柱或菌块栽培平菇、姬菇、鸡腿菇,研究了碎段棉秆模具式栽培食用菌的配套技术,为栽培食用菌开辟了新途径。试验结果证明,碎段棉秆采用模具栽培平菇、姬菇、鸡腿菇,方法简便,用工少、成本低、效益高,是一种全新的棉秆栽培食用菌模式。     

98-8番茄的选育

98-8番茄为中早熟品种,无限生长型,第8～9片叶着生第一穗花,果实编高圆形,无青肩,平均单果重250～300g,果色粉红,果肉较厚,硬度高,耐裂果,耐贮运.一般667 m2产量5 000kg以上.田间表现高抗叶霉病(cf5基因).     

Effect of treating soybean with 2,6-dichloroisonicotinic acid (INA) and benzothiadiazole (BTH) on seed yields and the level of disease caused by Sclerotinia sclerotiorum in field and greenhouse studies

Field or greenhouse grown soybeans were treated with 2,6-dichloroisonicotinic acid or benzothiadiazole and subsequently assessed for severity of white mold disease caused by Sclerotinia sclerotiorum. Three or four applications of 2,6-dichloroisonicotinic acid to field plots in 1993–1995 reduced severity of white mold after natural infection by 20–70% compared with water-treated controls in soybean cultivars Elgin 87 and Williams 82, which are considered to be highly susceptible to the disease. The effect was not as large in the cultivars Corsoy 79 and NKS19-90 which are more resistant to white mold. Two or four applications of benzothiadiazole to field plots in 1995 and 1996 reduced white mold severity by 20–60%, with the greatest reductions again observed in the more susceptible cultivars. Corresponding yields were increased compared with controls, particularly for the susceptible cultivars under conditions of high disease pressure. In greenhouse trials multiple applications of either compound resulted in significantly smaller lesion diameters following subsequent leaf inoculations with the fungus. The compounds did not result in observable phytotoxicity or inhibit growth of Sclerotinia sp. in vitro. We hypothesize that the decrease in disease severity following treatment with INA or BTH is a result of resistance induction.