The reproductive biology and genetic diversity of Potamophila parviflora R. Br.

Potamophila parviflora, a wild relative ofdomestic rice, is endemic to the north-eastern river systemsof New South Wales, Australia. It is the only member of the genus,and is habitat specific. Several new sites were found, mostly in theUpper Clarence catchment. Florets of P.parviflora were found to be 86%female-only, while 14% contained mature malereproductive parts, which occurred more often in the middle sectionof the panicle. Pollen was found to be necessary for the developmentof mature fruits. RAPD data showed that there is very little geneticvariation between individual plants, or between differentpopulations. An embryological study showed several irregularities inmegasporogenesis and megagametogenesis. No tetrads were observed inmegasporogenesis and the ovule is vacuolate at the megaspore mothercell stage. Megagametogenesis proceeded rapidly, nuclei within theovule were sometimes not spherical and varied in size, and sometimesthe antipodal cells doubled in number with a corresponding halving insize of the nuclei. Chromosome number varied between 2n = 24and 2n = 25, between and within populations. These resultsindicate that P. parvifloracould be a diplosporous apomict of the Antennaria type, althoughfurther works are required to provide conclusive proof.     

山西绵核桃无融合生殖特性研究

山西绵核桃是我国核桃重要的栽培类型,以山西绵核桃为试材研究了其无融合生殖特性。套袋隔离结果表明,4个供试核桃单系均具有一定的无融合生殖能力,平均无融合生殖率为20.4%,最高达67.4%;方差分析结果显示不同地区来源单系间无融合生殖能力的差异达极显著水平,说明山西绵核桃群体中存在专性无融合生殖类型。山西绵核桃无融合生殖胚由卵细胞发育而来,属孤雌生殖类型。具无融合生殖特性的山西绵核桃后代叶片过氧化物酶同工酶酶谱一致性高于自然授粉后代。讨论了培育具无融合生殖特性的核桃新品种的可能性。     

栽培甜菜和白花甜菜种间杂交后代无融合生殖的观察

栽培甜菜和白花甜菜杂交获得的Ｆ＿１代以栽培甜菜连续回交产生了Ｂ＿１Ｆ＿２代和Ｂ＿２Ｆ＿３代￣［４］．在Ｂ＿２Ｆ＿３代中，２ｎ＝２７的植株达３０．１９％，推测其中大多数染色体组仍为ＶＶＣ。具有ＶＶＣ染色体组的核型中，含９个白花甜菜校长的染色体和１８个较短的栽培甜菜染色体，差别明显，易于区分。我们通过对Ｂ＿１Ｆ＿２（Ｂ１４，２ｎ＝２７）和Ｂ＿２Ｆ－３（２ｎ＝２７）植株间形态特征相似性比较、两个世代植株有丝分裂特异核型比较、两类植株减粉分裂行为比较、过氧化物酶和酯酶同工酶酶谱相似性比较，有力地证明了栽培甜菜和白花甜菜种间杂交后代中，从Ｂ＿１Ｆ＿２（Ｂ１４）到Ｂ＿２Ｆ＿３之间传递上存在着无融合生殖现象。     

二十一世纪水稻育种新战略

本文论述了远缘杂交和多倍体化结合利用基因组间和多倍体杂种优势,开创水稻育种新途径的策略。纵观水稻育种的历史,无论是常规杂交育种,还是杂交稻育种,其研究战略都是建立在有性生殖和二倍体基础上的,归根结底,都是利用栽培稻同一基因组（A基因组）内优良基因的重组以及从野生稻向栽培稻引入少数优良基因。从作物进化     

苹果属植物无融合生殖研究进展—文献综述

自本世纪３０年代在苹果属植物中发现无融合生殖现象以来，有关苹果属植物无融合生殖的细胞学、遗传学、胚胎学研究，无融合生殖的种类、类型、能力和在栽培、育种等方面的应用研究多有报道。本文总结了这些研究所取得的重要进展，对比当今植物无融合生殖研究现况，提出了苹果属植物无融合生殖今后的研究方向。关键词     

核桃无融合生殖现象及其矿质营养变化研究

对核桃的无融合生殖结实率和年生长周期中矿质营养含量进行了研究,结果表明:4个供试品种都具有一定的无融合生殖能力,平均无融合生殖率为15.72%,最高达37.5%;除Fe元素外,无融合生殖果实中其他元素的含量在年周期中都呈下降趋势,而下降的时期略有不同。     

Cytogeography and variation of stomatal size of Paspalum Glaucescens (Gramineae; Paniceae) in Southern Brazil

Paspalum glaucescens belongs to the informal group Plicatula, reproductively characterized by the dominance of tetraploid apomitic lines in most of its populations, with rare diploid, sexual counterparts. The species shows high phenotypic variation. Twenty nine Southern Brazilian accessions were cytologically and morphologically analysed. Most of the accessions were tetraploid (2n = 4x = 40). Meiotic study of three tetraploids showed their irregular behaviour. Eight accessions presented the diploid level (2n = 2x = 20).This can be considered a very high frequency of diploids in a member of the Plicatula group. While the tetraploids are concentrated at the highest elevations, diploids were detected mostly in the lowlands. Average stomatal sizes were quite distinct on different ploidy levels, being larger in tetraploids. This revised version was published online in July 2006 with corrections to the Cover Date.     

被子植物的无融合生殖和它的应用前景

无融合生殖是植物以无性繁殖产生种子的一种生殖方式.被子植物的无融合生殖以其发生的细胞学机制分为:未减数配子体无融合生殖;减数配子体无融合生殖和珠心胚结构(或孢子体无融合生殖)三种不同的基本类型.体细胞无孢子生殖,二倍体孢子生殖和珠心胚结构是被子植物常见的无融合生殖类型.这三种常见类型发生的细胞学机制和遗传特     

龙须草生态型的划分及其遗传差异的AFLP分析

 利用AFLP分子标记技术，结合形态学特征观察和叶片纤维素等成分含量的测定，将来自4个省的9个不同居群的龙须草划分为4种生态型：窄叶类型（湖北）、浓绿叶类型（广西）、红秆类型（陕西）和宽叶类型（河南）；来自同一地区的不同居群之间，遗传差异很小，聚为同一种生态型；同一居群内不同无融合生殖个体之间未检测到差异；分析了不同生态型之间的遗传差异和亲缘关系；讨论了AFLP技术在无融合生殖植物的分类和遗传学研究中的应用前景。     

禾本科牧草无融合生殖的研究进展

介绍了目前已发现的具有无融合生殖现象的牧草及其在植物育种中的研究现状、鉴定方法和发展方向。