Effect of high temperature on plasmid curing of Rhizobium spp. in relation to nodulation of pigeonpea [Cajanus cajan (L.) Millsp.]

Summary Fifty-six isolates of Rhizobium and Bradyrhizobium spp. (Cajanus) were studied for their plasmid profile and N₂-fixation efficacy. One to three plasmids were reproducibly detected in all the Rhizobium spp. strains but no plasmid was detected in the Bradyrhizobium spp. strains. Rhizobium sp. strain P-1 was mutagenized by Tn5 and three nod^– and six nod⁺fix^– were screened for symbiotic parameters. Neomycin-sensitive mutants were isolated by elevated temperatrue (40°C) from tranconjugants carrying Tn5 insertions. The high temperature cured these mutants from the single large plasmid present in the parent strain P-1. All these cured mutants were nod^–, indicating that the genes for nodulation were present on this plasmid, which is readily cured at a high temperature (40°C). The high temperature in the semi-arid zones of Haryana could be responsible for the low nodulation of pigeonpea because the plasmid carrying the nodulation genes is cured at 40°–45°C giving rise to non-nodulating mutants.     

散叶烤房系列研究 1.烘烤性能研究

2004—2005年通过测试装烟室内平面温差、垂直温差以及叶间隙风速风压的方法研究了散叶烤房的烘烤性能,结果表明:只要装烟板制作规范、装烟室地坪坡度合理、风机风压达到设计要求、装烟室单位面积风量≥1000m3/h,装烟室平面温差就能控制在1℃以内;散叶烤房的垂直温差表现为,在变黄初期最小,从变黄中期到定色结束,温差逐步扩大,干筋期又逐步缩小的规律。但和普通密集烤房相比,散叶烤房上下层温差较小。     

Effect of glycols and catalysts on cotton fabrics treated with glyoxal

The optimum conditions for durable press treatment of cotton fabrics using glyoxal as a nonformaldehyde crosslinking agent were investigated. Crosslinking reaction was conducted in the presence of different catalysts such as aluminum sulfate, magnesium chloride, or magnesium chloride-citric acid mixture at various mole ratios of catalyst to glyoxal. Aluminum sulfate was proven the most effective one among those used. Glycol addition into a glyoxal padding bath increased the wrinkle recovery angle(WRA) and whiteness of treated fabrics. The optimum mole ratio of glycol to glyoxal was 1:1. Diethylene glycol addition produced better overall performance to the glyoxal-crosslinked fabric compared to ethylene glycol addition.     

不同成熟烟叶在烘烤过程中的叶片组织结构变化研究

烟叶的成熟度决定了其叶组织的结构,不同成熟度烟叶的组织结构烘烤后有较大的差异,为探明不同成熟烟叶在烘烤中的组织结构变化规律,对烤烟K236品种的中部初熟、适熟和过熟烟叶在烘烤过程中定时取样进行快速石蜡包埋切片,观察分析组织结构。结果表明:烘烤过程中叶片厚度、上表皮细胞厚度、上表皮细胞宽度、下表皮细胞厚度、下表皮细胞宽度、栅栏组织厚度、栅栏细胞间隙、海绵组织厚度和海绵细胞间隙的收缩以过熟烟叶过熟烟叶>适熟烟叶>初熟烟叶;在烟叶干燥收缩过程中以各组织的收缩以过熟烟叶较剧烈,适熟烟叶居中,初熟烟叶较平缓;无论是何种成熟的烟叶的上表皮细胞厚度、上表皮细胞宽度、栅栏组织厚度和栅栏细胞间隙的收缩率均高于下表皮细胞厚度、下表皮细胞宽度、海绵组织厚度和海绵细胞间隙。     

在不同烘烤环境下烟叶淀粉酶和淀粉磷酸化酶活性的变化规律研究

以红花大金元和K326烤烟品种的中部叶为材料,研究了烘烤过程中及不同烘烤环境下淀粉酶和淀粉磷酸化酶活性的变化规律。结果表明:烘烤过程中烟叶淀粉酶活性出现2次高峰,分别在烘烤的36和72h;在鲜烟叶中淀粉磷酸化酶活性较高,随着烘烤过程的推进,至24h达第1次高峰,之后降低,48h时出现低谷,随后又于72h达第2次高峰。在整个烘烤过程中,采用低温低湿变黄,慢速升温定色的烘烤环境,烟叶内淀粉酶和淀粉磷酸化酶活性较高,有利于烟叶淀粉的降解。     

去基烟叶在密集烘烤过程中的水分变化及其烘烤效果分析

[目的]探索最佳的烟叶烘烤方式和烘烤工艺技术,适应烟叶工场化烘烤的发展趋势。[方法]以烤烟品种K326为供试材料,采用双因素随机区组设计,研究了去基烘烤过程中烟叶失水干燥变化规律、不同烘烤工艺对去基烘烤质量的影响,并对2种烘烤模式的能耗、用工、烘烤时间进行了对比。[结果]试验表明,去基烟叶在烘烤过程中,水分变化趋势表现为前期失水量少、失水速率小,后期失水量多、失水速率大,失水速率大于常规整叶烘烤;去基烟叶在烤后经济效益及烟叶质量方面表现优于常规整叶烘烤;在节能减耗方面,去基烟叶烘烤时间缩短,能耗有所降低,烘烤投资减少。[结论]烟叶去基烘烤模式具有节能环保、降本增效等优势,有较大的推广价值。     

安康烤烟的烘烤特性及适宜成熟度研究

以烤烟 K326、云烟87和贵烟4号为材料,研究了陕西安康烟区烤烟烘烤特性和适宜采收成熟度的关系。结果表明：K326失水较慢,相对耐烤,但易烤性一般,云烟87和贵烟4号失水较快,易烤,但耐烤性一般;贵烟4号以 CM1收缩率最大,K326和云烟87以CM2收缩率最大,CM1最小,但差异不显著;K326分别以 XM2、CM2、BM2的上中等烟比例和均价最高,云烟87分别以 XM1、CM3、BM2的上中等烟比例和均价最高;K326分别以 XM2、CM2、BM2的化学成分协调性和感官质量总体表现最好。     

Preparation and properties of crosslinkable waterborne polyurethanes containing aminoplast

In order to improve the water swelling, thermal/mechanical and adhesion properties of waterborne polyurethane (WBPU), a series of the crosslinkable WBPUs containing hydrophilic ionic component, dimethylol propionic acid (20 mole%), were prepared by in-situ polymerization using a cross-linker hexakis (methoxymethyl) melamine (HMMM). Effects of the HMMM content (2, 4, and 6 wt%) and curing temperature on these properties of the crosslinked WBPUs samples were investigated. All properties were found to increase with increasing HMMM content. It was found that the optimum curing temperature of the WBPU films and adhesives was near 120°C, which was not dependent on the HMMM content.     

密集烤房“3层改4层”烘烤试验研究

通过对比试验研究了密集烤房3层和4层烘烤方式对烤烟能耗和烟叶品质的影响。结果表明:与常规3层挂烟相比,4层挂烟方式明显增加了烤房容量,每1kg干烟用工成本下降20.06%,耗能成本降低22.78%,烤后烟叶质量优于3层烘烤,具有广泛的推广价值。     

生物质燃料烘烤应用研究

本文对生物质燃料烘烤和燃煤烘烤的烤后烟叶经济性状、外观质量、炉中烘烤用工数量及燃料消耗进行比较分析,旨在为生物质烘烤示范推广提供参考依据。结果表明,与常规燃料烘烤相比,生物质颗粒燃料烘烤后烟叶经济性状表现较好,上等烟比例、均价较高,外观质量整体较好。同时,生物质颗粒燃料烘烤用工、燃料消耗都比燃煤烘烤低。