病、健鸡不同肠段正常菌群的研究

本项研究测定了病、健鸡空肠和直肠的双歧杆菌等11种细菌,结果显示鸡白痢病具有明显的肠内菌群失调。拟杆菌显著减少(P<0.01),大肠杆菌菌数增加(P<.0.1)而乳酸杆菌等7种茵无明显变化。     

高山杜鹃茎段组织培养和优化体系的建立

以高山杜鹃茎段为外植体,研究不同品种、不同激素组合对5个高山杜鹃品种无菌芽发生的影响,并以品种Jeande Marle Montague为试验材料,研究不同激素组合对试管苗生根和增殖的影响。结果表明:茎段外植体均能诱导萌发,最佳诱导培养基为WPM TDZ(0.5 mg.L-1),诱导率为90.4%;试管苗继代增殖培养基为WPM TDZ(0.5 mg.L-1) NAA(1.0 mg.L-1),增殖系数达7.96;试管苗生根培养基为1/2 WPM NAA(0.25 mg.L-1) IBA(0.25 mg.L-1),生根率为98.6%。试管苗移栽到泥炭、珍珠岩(体积比为4¨1)基质中,成活率达98%以上。     

东祁连山杜鹃属植物光合作用特点的研究

对东祁连山杜鹃灌丛中杜鹃属植物光合作用特点的研究结果表明:4种杜鹃的净光合速率较低,头花杜鹃、百里香杜鹃、烈香杜鹃和陇蜀杜鹃在7月分别为5.06、6.13、7.23、7.44 m mol CO2 m-2穝-1,在10月分别为-0.12、0.032、-0.063、1.218 m mol CO2 m-2穝-1。前3种杜鹃的净光合速率与光通量密度存在正相关关系(r分别为0.936 4、0.850 1、0.817 8),陇蜀杜鹃则相关性不显著。头花杜鹃和百里香杜鹃的净光合速率在光通量密度达到1 000 m mol m-2穝-1时开始下降,而烈香杜鹃和陇蜀杜鹃则在达到1 400 m mol m-2穝-1时开始下降。4种杜鹃在13 : 00～14 : 00发生光合午休现象。     

Radiation induced chimeric rearrangement in flower structure of Rhododendron simsii Planch. (Azalea indica L.). Use of recurrent irradiation

Summary A radiation-induced chimeric flower colour sport of vegetatively propagated Rhododendron simsii Planch. was recurrently irradiated (up to three times in three consecutive years) with soft X-rays (50kV-30mA), as compared to a single treatment. Because of the low true flower colour mutation frequency the efficiency of the different radiation treatments was compared on the basis of the number of chimeric rearrangements in flower structure i.e. the flower colour change from red with broad white edge towards either homogeneous carmine-red or white.It is quite clear that recurrent irradiation with appropiate doses is most efficient.     

Comparative study of the discriminating capacity and effectiveness of AFLP, STMS and EST markers in assessing genetic relationships among evergreen azaleas

The application of amplified fragment length polymorphism (AFLP), sequence tagged microsatellite site (STMS) and expressed sequence tag (EST) markers to study the genetic relationships in an evergreen azalea gene pool was investigated. STMS and EST markers revealed a higher genetic distance detection capacity than AFLPs, which, nevertheless, were the most efficient marker system due to their highest polymorphism detection capacity. Similarity matrices showed weak, yet significant, correlations when Mantel's test was applied. To assess the usefulness of the overall information provided by these marker data for establishing phylogenetic relationships and horticultural classification, cluster analysis was performed. The joint AFLP, STMS and EST data were demonstrated to be remarkably effective for group discrimination and phylogenetic studies. The use of these polymerase chain reaction marker systems is discussed in terms of the choice of appropriate marker techniques for different aspects of evergreen azalea germplasm evaluation.     

Stomatal Density and Length for Breeding of Evergreen Azaleas (Rhododendron simsii Planch.)

The hentability of stomatal density and stomatal length has been studied for four evergreen azalea (Rhododendron simsii Planch.) cultivars with the aim to evaluate the possibilities of stomatal characteristics of parental plants for increasing the crown diameter – hence yield – of the offspring., A nearly complete diallel cross with reciprocals has been carried out with the four parental cultivars. Highly significant general combining ability (GCA) values of the parents were found for stomatal length and density, but not for the crown diameter. GCA values of crown diameters did not correspond with GCA values of either stomatal length or stomatal density. Therefore it was concluded that utilizing stomatal characteristics as a selection tool for an increased crown diameter (yield) in azalea., may not be feasible. Differences in crown diameter could not be explained from correlations with either stomatal density or stomatal length.     

Diversity of flower colours in Rhododendron simsii Planch. and prospects for breeding

Summary A survey of the flower colours present in evergreen azaleas, Rhododendron simsii Planch is given. The following colours occur: white, red, carmine red, pink, purple and lilac. Crosses can lead to greater diversity although no really new shades have resulted. Quantitative anthocyanin and flavonol determinations for the cultivars enable us to gain an insight into the possiblities of increasing these contents and thus obtaining new colours. The prospects of breeding for intensely red, yellow and blue cultivars are also reviewed.     

The influence of cytokinins and ionic strength of Anderson's medium on shoot establishment and proliferation of evergreen azalea

Shoot-tip explants of evergreen azalea cv. Fuchsia grown on Anderson's medium and containing different cytokinins produced the highest proliferation rate on a medium containing thidiazuron (TDZ). TDZ concentrations ranging from 0.23 to 2.3 M resulted in both good bud-break rate (4 to 5) and shoot quality (> 0.5 cm in length). Adding 2.3 M zeatin to Anderson's medium containing 0.23 or 2.3 M TDZ increased the number of axillary shoots/explant. However, increasing the zeatin concentration to 4.6 M resulted in a reduced shoot proliferation rate. A medium containing 1.15 M TDZ and 2.3 M zeatin resulted in an 18-fold increase for 'Fuchsia' and a 9-fold increase for 'Hino Crimson' after 6 weeks of culture. It was found that explants grown on a half-strength Anderson's medium with 87.6 mM sucrose generally had better shoot proliferation rate and shoot quality than at higher ionic strength.     

遮阴对迷人杜鹃种子萌发和芽苗生长的影响

为给迷人杜鹃的抚育管理提供参考,采用盆栽法人工模拟光照条件,探索不同遮阴处理对迷人杜鹃种子萌发和芽苗生长的影响试验。结果表明:迷人杜鹃种子萌发率和萌发指数在30%遮阴处理时达到最大,分别为90.00%和2.46;随着光照的减弱而逐渐减小,在80%遮阴处理下最小,为40%和0.27。弱光照对种子萌发进程有一定的延迟作用,萌发活力指数随着光照的减弱而减小。不同遮阴处理的迷人杜鹃芽苗具有较大的形态学可塑性,30%遮阴处理的芽苗胚根长、胚轴长、芽苗活力指数和幼叶宽均最大,分别比全光照提高60.71%、29.91%、52.26%和33.33%;80%遮阴处理最小,分别比全光照降低59.09%、54.88%、74.32%和66.67%。随着遮阴度的增加,幼苗的根系活力降低,而总叶绿素含量先上升后降低,根系活力以30%遮阴处理最大,为3.49mg/(g·h);MDA含量以80%遮阴处理最大,为13.42nmol/g FW;叶绿素含量以50%遮阴处理最大,为75.32μg/g。遮阴度为30%的光照环境有利于迷人杜鹃盆栽育苗。     

青海杜鹃属植物种质资源及园林应用

在了解青海野生杜鹃属植物种质资源调查现状的基础上,从中筛选出观赏价值较高的15种野生杜娟属植物,并对所选植物利用分层聚类的方法,研究其亲缘关系,分析其园林用途。