温室用复合调湿材料特性的试验研究

为探讨自制复合调湿材料替代温室后墙体内表面部分红砖的可行性,对密闭空间内的复合调湿材料进行了调湿能力研究,同时,在室温条件下对其进行了热工和力学性能的试验研究。结果表明:密闭空间的复合调湿材料其饱和吸湿率可达130%;在40min内,相对湿度降低了23%,即相对湿度由92.5%降低到了69.5%,在13h内相对湿度降低到了30.5%,即由92.5%降低到62%,在高湿情况下吸湿的性能要高于硅胶,吸湿性能比较显著;复合调湿砌块能够满足温室内墙体材料的热工性能和机械性能的要求。     

绿僵菌在3种不同培养基上培养时产孢量的影响因素

分析了绿僵菌菌株在3种不同培养基上培养时其产孢量的2个影响因素(初始接种浓度和相对湿度),得出菌株在3种不同培养基上培养时须分别配以适宜的接种浓度和相对湿度,以获取最大产孢量(燕麦培养基:1×107cfu/mL,65%;PPDA培养基:1×106cfu/mL,85%;玉米粉酵母浸膏培养基:1×108cfu/mL,75%)。另外,随继代培养代数增加,菌株在这3种培养基上前五代的产孢量比较稳定,第七代及之后的产孢量明显下降。根据3种培养基不同的功能,在PPDA培养基上培养菌株时要着重注意不同继代培养代数对产孢量的影响,其它2种培养基培养菌株一般不超过五代,产孢量比较稳定。     

RH植物液肥在茶苗上的应用效果

采用RH植物液肥800倍进行苗圃对比试验,结果表明：对茎粗、株高等性状有显著作用,茶苗生长较为健壮。     

Laboratory studies to assess the risk of development of resistance to zoxamide

Laboratory studies were conducted to evaluate the risk of developing field resistance to zoxamide, a new Oomycete fungicide which acts on microtubules. Zoxamide, metalaxyl and dimethomorph were compared with respect to the ease with which fungicide‐resistant mutants could be isolated and their level of resistance. Attempts to generate mutants of Phytophthora capsici and P infestans with resistance to zoxamide by mycelial adaptation on fungicide‐amended medium were unsuccessful. Similarly, changes in sensitivity to zoxamide were small (resistance factors ≤2.2) in mutants of P capsici isolated by chemical mutagenesis of zoospore cysts. In parallel experiments with metalaxyl, highly resistant mutants were obtained using both adaptation (P capsici or P infestans) and chemical mutagenesis (P capsici). For dimethomorph, chemical mutagenesis (P capsici) yielded moderately resistant mutants (maximum resistance factor = 20.9), and adaptation (P capsici or P infestans) did not induce resistance. It is proposed that failure to isolate mutants resistant to zoxamide results from the diploid nature of Oomycete fungi and the likelihood that target‐site mutations would produce a recessive phenotype. Our studies suggest that the risk of a highly resistant pathogen population developing rapidly in the field is much lower for zoxamide than for metalaxyl. However, as with any site‐specific fungicide, appropriate precautions against resistance development should be taken. © 2001 Society of Chemical Industry     

Growth of pot roses and post-harvest rate of water loss as affected by air humidity and temperature variations during growth under continuous light

The effect of diurnal variations in air humidity and temperature under continuous lighting period (LP) on growth, flowering and water loss were studied in two pot-rose cultivars.     

影响虫生真菌玫烟色似青霉孢子萌发的因素探析

采用凹玻片悬滴法测定了温度、湿度、紫外照射及化学农药对玫烟色拟青霉孢子萌发的影响。结果表明,玫烟色拟青霉孢子萌发的适宜温区为20￣28℃,相对湿度在90%以上,紫外照射对该菌孢子萌发有很大影响。随紫外照射时间的延长,孢子萌发率明显降低。当照射时间为60min时,24h的孢子萌发率为54.2%,当照射时间达180min后,24h的孢子萌发率仅为5.4%,同时部分孢子的萌发时间显著被延长。不同杀虫剂及同一杀虫剂的不同浓度,对玫烟色拟青霉分生孢子萌发的影响不同。20%氰戊菊酯、22%蚜虱灵、5%的抑太保、25%灭幼脲四种供试农药的三种浓度对玫烟色拟青霉分生孢子萌发的影响均很小,因此这四种杀虫剂可作为玫烟色拟青霉混用的首选药剂;此外10%吡虫啉和绿荣的1/2常规浓度和1/4常规浓度对该菌分生孢子萌发的影响也较小,因此也可作为玫烟色拟青霉的复配药剂。     

牛ACAS2基因的克隆、序列分析及染色体物理定位

以中国西门塔尔牛肝脏组织为材料,运用同源序列克隆技术并结合RT-PCR技术,对牛ACAS 2基因的部分cDNA进行了克隆与序列分析,应用SUN bRH 7000型辐射杂种板对分离的牛ACAS 2基因进行了染色体定位。结果显示,本研究所获得的长为1 535 bp的cDNA序列为牛ACAS 2基因的部分编码序列,该段序列与人(G enB ank登录号:NM-139274)和小鼠(G enB ank登录号:NM-019811)的ACAS 2基因mRNA序列的相似性分别为91%和88%;牛ACAS 2基因被定位于牛的13号染色体上,与该染色体上的标记D IK 4350的距离为1.51 cR。     

生态因子对水稻Rubisco和光合日变化的调节

水稻光合日变化的研究表明,受一天中光强、湿度、温度和CO2浓度等因素变化的影响,Rubisco活力和光合速率有明显的日变化.采用多项式回归分析理论建立了较有预测能力的复合回归模式,以回归方程为数学模型形象描绘了各因子与光合速率之间的关系.结果表明,气孔导度(Sc)和Rubisco活力是影响水稻光合日变化的重要生理和生化因子,光强和湿度是影响水稻光合速率的重要生态因子.     

Temperature and photoperiod control of morphology and flowering time in two greenhouse grown Hydrangea macrophylla cultivars

Knowledge of the factors involved, and tools to control morphology and flowering are important in intensive and cost-efficient greenhouse production. Hydrangea macrophylla is an important flowering pot plant in Norway and is produced year-around in greenhouses. Due to problems in scheduling, a study was conducted to compare floral transition and morphology of two commercially important cultivars of Hydrangea (‘Early Blue’ and ‘Schneeball’) under different flower initiating treatments in growth chambers. Plants were grown with high pressure sodium lamps (HPS) at moderate temperature (17 °C) (MT) and high (24 °C) temperature. At high temperature, the effect of (1) irradiance under long day conditions (16 h lighting with 70 or 200 μmol m⁻² s⁻¹), and (2) short day (8 h lighting) was investigated. The short day treatment had similar light integral as the low irradiance long day treatment (SD: 8 h × 140 μmol m⁻² s⁻¹ and LD: 16 h × 70 μmol m⁻² s⁻¹ = 4.0 mol m⁻² d⁻¹). The intention was to test the effect of irradiance and SD on flower transition and morphology under high temperatures. The results clearly showed that MT is the strongest signal for floral transition. MT resulted in a rapid floral transition of the terminal buds and lateral flower buds. A short forcing period was required and the plants became short and compact without any use of chemical growth retardants. At high temperatures only SD had a promotive effect on flower transition and the response was found to be stronger in ‘Schneeball’ than ‘Early Blue’. In general, all the treatments under high temperatures required a long forcing time and the plants tended to be very tall with a low number of lateral flower buds.