刺梨及部分近缘种形态学性状和RAPD标记分析

 通过36个形态学性状和29个引物RAPD扩增获得的分子标记，探索刺梨及部分近缘种的亲缘关系。结果表明，普通刺梨所有基因型之间的亲缘关系较近，而与其余种类相对较远；无籽刺梨与贵州缫丝花的遗传距离较近，形态学和RAPD聚类分析都显示很近的亲缘关系；尽管两类遗传距离的排序和聚类分析有一定差异，但Mantel相关性检测表现出显著相关性(r=0.6122，P<0.01)。还就无籽刺梨的可能来源进行了讨论。     

枳属36份特异种质的AFLP指纹图谱构建与分析

 从40个Pstl／MseI酶切的AFLP引物对中筛选出多态性高的7个，对36份枳属特异种质进行了指纹分析。7个引物对共获得539条带，其中146条带具有多态性。各种质材料之间的遗传相似性在0．23～ 0．98之间，只需结合其中的3个引物对即可区分所有的材料。根据7个AFLP引物对所得谱带的聚类分析表明，聚类结果与地理来源没有明显的联系，这可能正反映了近时间内地区之间枳资源的频繁交流。     

植物保护剂保卫德对黄曲条跳甲种群的控制作用

通过室内外试验评价了植物保护剂保卫德(BIOACT-T35)对黄曲条跳甲Phyllotreta striolata(F.)种群的控制作用。结果表明,其控制作用主要表现在对成虫的显著忌避和拒食作用。10.00 ml/L的忌避作用为91.42％,选择性和非选择性拒食率分别为93.54％和85.79％,种群趋势指数(I值)由对照的3.8680降为0.3676,干扰作用控制指数(IIPC)为0.0950。采用状态空间分析法的模拟结果表明,其控制作用表现在种群发展初期对成虫的忌避作用。     

不同添加剂对辣椒酱质量的影响

本文通过实验研究了不同添加剂对辣椒酱的影响。结果表明，当辣酱用量为果酱的5倍，增稠剂用量为0.8%，盐为3%，白砂糖为8%时，辣椒酱的风味和外观形态最好；而辣椒采用8%的食盐进行腌制，再加入5?M作为钙的营养强化剂时产品的钙营养价值提高，风味更好。     

昆虫对苏云金杆菌抗性的研究进展(Ⅰ): 抗性的特点及其机制

本文详细阐述了昆虫对苏云金杆菌（Ｂｔ）产生抗性和这个抗性的特点。通过分析Ｂｔ杀虫作用方式，进一步从生化、生理、行为等方面因素探讨了昆虫对Ｂｔ产生抗性的机制。     

农药对靶喷撒技术研究初报

通过稻，麦，棉，茶，黄瓜，油菜等作物上一系列农药喷撒试验和生产性示范表明，采用对靶喷撒技术和相应的喷撒手段，可显著提高农药在有效靶区的沉积率，农药用量可％－５０％，喷雾用水量可降低９５％以上。农药对靶喷撒技术是根据病菌或害虫在作物上的分布，作物的田间群体结构以及农药雾滴在株冠中的行为的综合研究所提出的化学防治法的一项基本原理和基本技术。     

粟羽、白羽和黄羽鹌鹑红细胞和血浆酯酶的遗传多态性研究

利用垂直板聚丙烯酰胺凝胶电泳法对蛋用朝鲜龙城系栗羽鹌鹑及其突变系白羽和黄羽鹌鹑的红细胞和血浆酯酶的遗传多态性进行了研究。结果表明：红细胞酯酶Es-Ⅰ、Es-Ⅲ和血浆酯酶Es-3、Es-4均存在遗传多态性，其中Es-Ⅰ和Es-Ⅲ、Es-3分别受常染色体上的一对等位基因A和B控制，各出现3种表型A、AB和B。Es-4出现2种表型即有带型和无带型，受显性基因Es-4^A和隐性基因Es-4^a控制。经适合性x^2检验，3群体在红细胞酯酶Es—Ⅰ位点的基因分布均显著偏离Hardy—Weinberg平衡（P〈0．01）。黄羽和白羽鹌鹑的红细胞酯酶Es-Ⅲ和血浆酯酶Es-3两个位点，均处于遗传平衡状态。     

木薯细菌性萎蔫病菌的检疫方法研究

本文对木薯细菌性萎蔫病菌的致病性测定、细菌的分离、细菌的培养条件和培养基选择、细菌的生理生化测定、分子生物学鉴定方法等方面进行了系统研究，确定了该病菌的菌落鉴定特征，建立了从木薯繁殖材料上进行病原菌检测的快速、灵敏、准确的PCR检测方法。     

Genetic structure of mulberry from different ecotypes revealed by ISSRs in China: An implications for conservation of local mulberry varieties

Mulberry is a perennial and economically important plant that has traditionally been used for feeding the silkworm. Evaluating genetic relationship is important for long-term improvement in mulberry yield, quality and resistance, and for germplasm conservation and identification. Population structure and genetic diversity of 8 mulberry populations from different ecotypes in China were analyzed by ISSR markers. Twelve ISSR primers generated a total of 83 amplification products, of which 50 were polymorphic, revealing 60.24% polymorphism among 66 mulberry local varieties, the mean PIC value was 0.1469. The total heterozygosity (H_T), heterozygosity within population (H_S), diversity between populations (D_ST) were 0.1600, 0.0851 and 0.0749, respectively. The coefficient of population differentiation (G_ST) was 0.4683, indicating that the variations among populations and those within populations contributed 46.8% and 53.2% to the total heterozygosity, respectively. The gene flow (N_m) was 0.5678, suggesting that genetic drift between populations can caused local genetic differentiation and therefore, population divergence. The mean genetic similarity coefficient was 0.8456, genetic similarity coefficient among 8 mulberry populations ranged from 0.8441 to 0.9640, indicating that genetic diversity of different populations existed variation. A dendrogram of all 66 local varieties of mulberry based on the genetic similarity using ISSR markers was generated by UPGMA cluster method. In the dendrogram, most varieties from the same ecotype clustered together.     

Predicting anisotropic shringkage of softwood Part 1: Theories

 The phenomenon of wood shrinkage by losing moisture can be analysed at four levels: molecular, ultrastructural, microstructural and macrostructural levels. To predict the shrinkage of wood cells, the model of Barber and Meylan is modified in the current work to reflect combined effects of shrinkage of the cell wall, changes of the lumen shape and effects of rays and bordered pits. Where a piece of wood contains a multi-layer of earlywood and latewood or multi-layer of normal and defect wood with variable properties, a model is proposed to relate the total, measurable shrinkage to the shrinkage of each layer. The model can be applied to a specimen with asymmetric properties through the thickness. In such a board, bow (or crook), cup and twist are often observed. The modified and proposed models involve several mechanical properties of the cell wall which are difficult to measure. These properties vary with wood types, such as earlywood, late wood, compression wood, or wood with spiral grain. However, an alternative method may be used to obtain these properties from experimentally measured shrinkage data, and this method will be presented in a subsequent paper. Received 25 January 1999