小麦与赖草远缘杂交的受精和胚胎发育

对小麦（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ Ｌ．）和赖草（Ｌｅｙｍ ｕｓｓｅｃａｌｉｎｕｓＴｚｒｅｌ．）杂交的受精和胚胎发育进行了观察．赖草花粉在小麦柱头上萌发良好,花粉管可顺利长入花柱和胚囊,在检查过的３１９个小麦子房中,６２个（１９．４４％ ）发生了双受精,产生了胚和胚乳,但胚乳的发育往往落后于胚的发育;４９个（１５．３６％ ）发生了单卵受精,只产生胚而无胚乳;７个（２．１９％ ）发生了单极核受精,只产生胚乳而无胚．小麦×赖草虽然总受精率可高达３６．９９％ ,然而由于胚乳的缺乏或发育不完全,致使最后结实率很低．从１５０朵授过赖草花粉的小麦颖花中,只得到１粒种子．表明利用胚培养技术对杂种胚进行早期离体培养,可望提高杂种植株的获得率     

窄颖仲彬草生物系统学研究

窄颖仲彬草Ｋｅｎｇｙｉｌｉａ ｓｔｅｎａｃｈｙｒａ（Ｋｅｎｇ） Ｊ．Ｌ． Ｙａｎｇ ,Ｙｅｎ ｅｔ Ｂａｕｍ 是分布于我国西部的一种多年生六倍体植物。将其与犬草Ｅｌｙｍｕｓ ｃａｎｉｎｕｓ（Ｌ．） Ｌ．, 鹅观草Ｒｏｅｇｎｅｒｉａ ｋａｍｏｊｉ Ｏｈｗｉ, 糙毛仲彬草Ｋ．ｈｉｒｓｕｔａ （Ｋｅｎｇ） Ｊ．Ｌ．Ｙａｎｇ,Ｙｅｎ ｅｔ Ｂａｕｍ ３ 个种进行了杂交。对亲本及杂种Ｆ１ 代花粉母细胞减数分裂中期Ｉ染色体配对行为进行了观察。减数分裂平均构型分别为： Ｅ． ｃａｎｉｎｕｓ×Ｋ． ｓｔｅｎａｃｈｙｒａ２３－７９ Ⅰ＋ ５－２０ Ⅱ＋ ０－２７Ⅲ; Ｒ．ｋａｍｏｊｉ ×Ｋ．ｓｔｅｎａｃｈｙｒａ１８－２３ Ⅰ＋ １１－６８ Ⅱ＋ ０－０６ Ⅲ＋ ０－０６ Ⅳ; Ｋ．ｈｉｒｓｕｔａ ×Ｋ．ｓｔｅｎａｃｈｙｒａ４－８３Ⅰ＋ １７－３１ Ⅱ＋ ０－５５ Ⅲ＋ ０－２０ Ⅳ＋ ０－０２ Ⅴ。根据以上结果, 结合种的形态特征, 窄颖仲彬草应从鹅观草属Ｒｏｅｇｎｅｒｉａ Ｃ． Ｋｏｃｈ 拟冰草组ＰａｒａｇｒｏｐｙｒｏｎＫｅｎｇ 中组合到仲彬草属Ｋｅｎｇｙｉｌｉａ Ｙｅｎ ｅｔ Ｙａｎｇ。     

普通小麦与冰草间杂种的细胞遗传学及其自交可育性

为了进一步研究冰草属（Ａｇｒｏｐｙｒｏｎ Ｇａｅｒｔｎ．）的Ｐ染色体组与小麦染色体组间的遗传关系和评价Ｐ染色体组在属间杂种自交可育性上的遗传效应,获得了普通小麦品种Ｆｕｋｕｈｏ（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ ｃｖ．Ｆｕｋｕｈｏ,２ｎ＝４２;ＡＡＢＢＤＤ）与３个不同来源的四倍体冰草（Ａ．ｃｒｉｓｔａｔｕｍ＜Ｌ．＞Ｇａｅｒｔｎ．,２ｎ＝２８;ＰＰＰＰ）间的杂种（２ｎ＝３５;ＡＢＤＰＰ）。结果表明     

甘蓝型油菜和白菜型油菜种间杂种的小孢子培养

利用分离小孢子培养从甘蓝型油菜（Ｂｒａｓｓｉｃａ ｎａｐｕｓ）和白菜型油菜（Ｂ． ｃａｍ ｐｅｓｔｒｉｓ）种间杂种中获得了胚和再生植株。所用的培养程序是,将甘蓝型油菜和白菜型油菜杂种小孢子在蔗糖浓度为１７％ 、ＢＡ 为０．１ ｍ ｇ／Ｌ的液体ＮＬＮ 培养基中３２ ℃下暗培养４８ ｈ,再转入蔗糖浓度为１０％ 的ＮＬＮ 培养液中２５ ℃下暗培养３ 周。不同杂种间小孢子胚胎发生能力存在差异,其中ＵＭ９２１（白菜型油菜）×９１１１８６（甘蓝型油菜）正反交杂种的胚产量显著高于供试的其它组合。供体植株种植在１０ ℃／５ ℃（昼／夜）条件下能显著改善杂种小孢子胚产量和质量。杂种小孢子胚产量和杂种植株每荚种子数存在极显著正相关,但杂种植株的花粉育性和胚产量间相关不显著。大多数甘蓝型油菜和白菜型油菜杂种小孢子胚衍生植株为非整倍体,２２．８％ 的植株起源于具亲本染色体数的小孢子,几乎全部为ｎ＝ １９ 的类型。讨论了影响种间杂种小孢子胚胎发生的因素以及种间杂种小孢子培养技术的可能用途     

辣椒属种间杂种F_1植株的细胞遗传学研究

本文分析了南京早椒（ＣａｐｓｉｃｕｍｆｒｕｔｅｓｃｅｎｓＬ．ｖａｒ．ＣｏｎｏｉｄｅｅｓＢａｉｌｅｙ）和Ｃ．ｃｈｉｎｅｎｓｅ二亲本及Ｆ１杂种花粉母细胞减数分裂终变期和中期Ｉ染色体配对的构型。结果表明：二亲本花粉母细胞减数分裂染色体配对均正常,为１２个二价体（双单倍体２ｎ＝２４）。Ｆ１杂种花粉母细胞减数分裂染色体配对很不规则。其平均频率分别为单价体０．０３６,二价体９．１８,三价体０．０３６,四价体０．８０,六价体０．３８。南京早椒和Ｃ．ｃｈｉｎｅｎｓｅ染色体间存在着相互易位,因此,二亲本间彼此有差异。单价体出现极少,这可断定南京早椒与Ｃ．ｃｈｉｎｅｎｓｅ染色体间是部分同源的,但染色体组结构上存在着差异。由于染色体结构上差异,所以Ｆ１杂种的育性较低。     

将大赖草种质转移给普通小麦的研究：VI.端体异附加系的选育与鉴定

利用根尖细胞有丝分裂中期染色体计数,花粉母细胞减数分裂中期１（ＰＭＣ ＭＩ）染色体构型分析仪及Ｃ－分带,从普通小麦中国春与大赖草（ＬｅｙｍｕｓｒａｃｅｍｏｓｕｓＬａｍ．）杂种回交后代中,选育出两个端二体异附加系９５Ｇ０９,９５Ｇ１１和一个添加了一对大赖草第１４号染色体和另一对端体的双重异附加系９５Ｇ３０２（２ｎ＝４４＋２ｔ）,它们的ＰＭＣ ＭＩ染色体配对构型分别为０．２１个单价体（其中０．１６个端     

莎草科植物硅酸体的研究

作者对国产莎草科１３个属６５种植物中成熟果实和叶片的硅酸体形态、发育和分布进行了系统的分析研究,结果表明：（１）莎草科植物硅酸体特征同其形态系统发育特征具有明显的相关性。所有莎草科植物的成熟果实表皮均具发育典型的帽状莎草Ⅰ型硅酸体,而在叶片上普遍发育莎草Ⅱ型硅酸体;说明莎草科是一个自然类群。（２）莎草科植物果实硅酸体特征在属间差异较大,在属下等级分类群之间差别一般较小;因而在高级分类群的划分上,具有较高的系统分类意义。（３）莎草Ⅱ型硅酸体相在种间及种下水平的分类研究中有较大的意义。根据莎草科植物莎草Ⅰ型果实硅酸体的形态特征,可以将这１３个属划分为三类：１、这种类型包括嵩草属（Ｋｏｂｒｅｓｉａ）,苔草属（Ｃａｒｅｘ）,扁穗苔属（Ｂｌｙｓｍｏｃａｒｅｓ）;２、包括羊胡子草属（Ｅ ｒｉｏｐｈｏｒｕｍ）,荸荠属（Ｅｌｅｏｃｈａｒｉｘ）,扁穗草属（Ｂｌｙｓｍｕｓ）,飘佛草属（Ｆｉｍｂｒｉｓｔｙｌｉｓ）,莎草属（Ｃｙｐｅｒｕｓ）,水莎草属（Ｊｕｎｃｅｌｕｓ）,水蜈蚣属（Ｋｙｌｉｎｇａ）;３、包括珍珠茅属（Ｓｃｌｅｒｉａ）,砖子苗属（Ｍａｒｉｓｃｕｓ）,扁莎草属（Ｐｙｃｒｅｕｓ）。     

大赖草及近缘物种原位杂交和Southern杂交的分析

用Ｔｈｉｎｏｐｙｒｕｍｂｅｓａｒａｂｉｃｕｍ（Ｓａｖｕｌ．＆Ｒａｙｓ）Ａ．Ｌｖｅ的基因组ＤＮＡ作探针,分别与大赖草Ｌｅｙｍｕｓｒａｃｅｍｏｓｕｓ（Ｌａｍ．）Ｔｚｖｅｌ．和脆轴偃麦草Ｔｈ．ｊｕｎｃｅｕｍ（Ｓａｖｕｌ．＆Ｒａｙｓ）Ａ．Ｌｖｅ的体细胞杂交,大赖草的１４对染色体均出现杂交信号,脆轴偃麦草只有７对染色体有杂交信号。在用重复ＤＮＡ序列ＰＨｖ６２作探针的原位杂交中,Ｔｈ．ｂｅｓａｒａｂｉｃｕｍ有４对染色体有杂交信号,大赖草有１３对染色体显示杂交信号,新麦草Ｐｓａｔｈｙｒｏｓｔａｃｈｙｓｊｕｎｃｅａ（Ｆｉｓｃｈ．）Ｎｅｖｓｋｉ和脆轴偃麦草无杂交信号。用ＰＨｖ６２作探针的Ｓｏｕｔｈｅｒｎ杂交结果与原位杂交相似。在被检测的１２个普通小麦大赖草异源染色体系中,除二体附加系中５Ｌｒ＃１和双二体附加系１Ｌｒ＃１＋５Ｌｒ＃１没有杂交信号外,其余的异染色体系与ＰＨｖ６２都有特异杂交信号。据此推测Ｔｈ．ｂｅｓａｒａｂｉｃｕｍ有可能参予了赖草属物种的形成过程。但是,大赖草的染色体组在进化过程中显然已发生过变异。     

湘中锡矿山邵东组和孟公坳组孢子组合——兼论泥盆—石炭系界线

湘中锡矿山邵东组和孟公坳组共产小孢子４５属８３种（含１０个新种,３个新联合）可划分为４个孢子组合,即：Ｒｅｔｓｉｐｏｒａｌｅｐｉｄｏｐｈｙｔａ－Ａｐｉｃｕｌｉｒｅｔｕｓｉｓｐｏｒａｆｒｕｃｔｉｃｏｓａ（ＬＦ）组合,Ｒｕｇｏｓｐｏｒａｃｆ．ｆｌｅｘｕｏｓａ－Ｒｅｔｉｓｐｏｒａｌｅｐｉｄｏｐｈｙｔａ（ＦＬ）组合,Ｌｏｐｈｏｚｏｎｏｔｒｉｌｅｔｅｓｅｘｃｉｓｕｓ－Ｒｅｔｉｓｐｏｒａｌｅｐｉｄｏｐｈｙｔａ     

大赖草及近缘种染色体C—分带的研究

对Ｔｈｉｎｏｐｙｒｕｍｎｂｅｓａｒａｂｉｃｕｍ（Ｓａｖｕｌ．＆Ｒａｙｓ）Ａ．Ｌｖｅ、新麦草（Ｐｓａｔｈｙｒｏｓｔａｃｈｙｓｊｕｎｃｅａ（Ｆｉｓｃｈ．）Ｎｅｖｓｋｉ）和大赖草（Ｌｅｙｍｕｓｒａｃｅｍｏｓｕｓ（Ｌａｍ．）Ｔｚｖｅｌ．）染色体Ｃ分带的核型进行了比较研究。Ｔｈ．ｂｅｓａｒａｂｉｃｕｍ和新麦草的染色体在Ｃ分带带型上有明显的差异,显示了物种的特异性。３个物种的核型表明,Ｃ带带纹主要分布在染色体的末端,大部分染色体不显着丝粒带和中间带。在大赖草染色体上的末端带很明显。一些大赖草的染色体具有与Ｔｈ．ｂｅｓａｒａｂｉｃｕｍ和新麦草某些染色体相似的Ｃ带带型。对大赖草染色体组与Ｔｈ．ｂｅｓａｒａｂｉｃｕｍ和新麦草染色体组的关系进行了讨论。     

Interspecific hybridization of perennial Medicago species using ovule-embryo culture

Summary New interspecific hybrids between alfalfa (Medicago sativa L.) and several perennial Medicago species were obtained by embryo rescue techniques. The methodology, designated ovule-embryo culture, involved preculturing the fertilized ovule (10 to 20 days post-pollination) for a period of six to 12 days followed by excision and direct culture of the embryo. Placement of the hybrid embryo directly onto culture medium without the interim ovule culture was unsuccessful. Ovule culture to germination without removing the embryo also was unsuccessful. Ovule-embryo culture was essential for recovering interspecific hybrids between diploid alfalfa (2n=2x=16) and the following diploid (2n=2x=16) species: M. hybrida Traut., M. marina L., M. papillosa Boiss., M. rhodopea Velen. and M. rupestris M.B. In addition, trispecies hybrids between M. sativa x M. dzhawakhetica Bordz. F₁ hybrids (2n=3x=24) and either M. cancellata M.B. (2n=6x=48) or M. saxatilis M.B. (2n=6x=48) were obtained from ovuleembryo culture. Media manipulations using M. sativa x M. rupestris F₁ and first backcross generation embryos demonstrated the optimum concentration of 12.5 mM NH₄ ⁺ for successful embryo rescue; ammonium salt formulation (whether chloride, nitrate or sulfate) was not critical. From a few thousand crosses, hybrids between M. sativa and either M. rhodopea or M. rupestris were recovered relatively efficiently with 157 and 66 hybrids, respectively. However, only 13 hybrids between M. sativa and M. papillosa were obtained from more than 2,000 crosses, and just two hybrids each have been recovered from the combinations M. sativa x M. hybrida and M. sativa x M. marina from 2,000 to 3,000 crosses. The predominant chromosome number between diploid alfalfa and the other diploid perennial species was 2n=2x=16. Morphology of the hybrids was generally intermediate. Electrophoretic analysis of the F₁ hybrids and parental clones on uniform or gradient polyacrylamide gels demonstrated that peroxidase phenotypes could be used to confirm hybridity. For all interspecific combinations there was at least one peroxidase isozyme unique to the wild species that was present in the F₁ interspecific hybrid.     

Relative developmental success of interspecific Lepomis hybrids as an estimate of gene regulatory divergence between species

The developmental success of interspecific Lepomis hybrids is used as an index of gene regulatory divergence between the green sunfish, L. cyanellus, and each of three other parental species, longear sunfish, L. megalotis, warmouth, L. gulosus, and bluegill, L. macrochirus. This gene regulatory divergence is compared to the degree of structural gene divergence among these four species (genetic distance [Nei, '78], D, ranged from 0.206 to 0.586). The developmental success of the hybrid embryos at the level of morphogenesis was higher than expected from the genetic distance between the parental species. The rates of morphogenesis of the hybrid embryos were the same as that for the green sunfish embryos. The percentage of embryos that hatched was relatively high in all crosses. However, two of the hybrid crosses resulted in enhanced percentages of hatched embryos. Slight increases in the extent of morphological abnormalities were observed in hybrids from crosses between more distantly related parental species. The schedules and levels of enzyme locus expression of the hybrids, assessed spectrophotometrically and electrophoretically for nine enzyme systems (encoded in a total of 14 loci), were different from each other and from those of the green sunfish embryos. Alterations in the time of first enzyme appearance and in the time of first increase in enzyme activity in the developing hybrid embryos were not correlated with genetic distance between parental species. However, the extents of alteration of enzyme activities over the entire period of hybrid embryogenesis were correlated with the genetic distance. We attribute the morphological and molecular anomalies observed in the hybrids to gene regulatory incompatibilities between species. Although the exact number of mutational differences and their relative developmental impacts are not known, some inferences can be drawn about the degree of divergence in gene regulation between species. It appears that an uncoupling of the rates of structural and regulatory gene evolution can occur between species of some taxa, an observation that has implications for the roles of gene regulatory differences in organismic evolution.     

Intergeneric hybridization between Hordeum and Secale (Poaceae). I. Crosses and development of hybrids

A total of 241 intergeneric combinations between Hordeum and Secale were attempted. It was only possible to obtain hybrid offspring from combinations with Hordeum as the female parent. By the aid of embryo culture technique 81 intergeneric combinations were synthesized, 72 of them not reported earlier. Generally hybridization with the polyploid species of Hordeum was most successful. Morphologically the hybrids were intermediate to the parents in most characters, though an obvious effect of genome dosage could be observed. Only few deviations from the expected chromosome numbers of the hybrids were found. All hybrid plants showed complete male sterility.     

Molecular characterization of reciprocal crosses of Aerides vandarum and Vanda stangeana (Orchidaceae) at the protocorm stage

Aerides vandarum and Vanda stangeana are two rare and endangered vandaceous orchids with immense floricultural traits. The intergeneric hybrids were synthesized by performing reciprocal crosses between them. In vitro germination response of the immature hybrid embryos was found to be best on half-strength Murashige and Skoog medium supplemented with 20% (v/v) coconut water/liquid endosperm from tender coconut. Determination of hybridity was made as early as the immature seeds or embryos germinated in vitro, using randomly amplified polymorphic DNA (RAPD) markers. Out of 15 arbitrarily chosen decamer RAPD primers, two were found to be useful in amplification of polymorphic bands specific to the parental species and their presence in the reciprocal crosses. However, a decisive profile that can identify the reciprocal crosses could not be provided by RAPD. Amplification of the trnL-F non-coding regions of chloroplast DNA of the parent species and hybrids aided easy identification of the reciprocal crosses from the fact that maternal inheritance of chloroplast DNA held true for these intergeneric hybrids. Subsequent restriction digestion of the polymerase chain reaction (PCR) amplified trnL-F non-coding regions of chloroplast DNA also consolidated the finding. Such PCR-based molecular markers could be used for early determination of hybridity and easy identification of the reciprocal crosses.     

枇杷属野生植物种胚离体培养和植株再生研究

以枇杷属Eriobotrya植物11个野生种、1个远缘杂交后代材料为试材,采用胚为外植体,在不同植物生长调节剂配比培养条件下,进行胚离体培养和植株再生研究。结果表明,胚培养的最佳培养基配方为MS + 6-BA 1.0 mg·L-1 + KT 1.0 mg·L-1 + NAA 0.1 mg·L-1。在此培养基中,所有试验材料均获得成功,其中栎叶枇杷E. prinoides的萌发率和丛芽率均达100%,有效地建立了枇杷属野生种的胚离体培养及其植株再生体系。     

节节麦×普通小麦杂种的胚援救和胚愈伤组织再生植株

通过活体-离体胚培养和胚愈伤组织培养有效地克服了节节麦(Aegilops tauschii Cosson.)×小麦(Triticum aestivum L.)杂种幼胚的败育,产生了大量的杂种植株。采用活体-离体胚培技术,节节麦×小麦三个组合杂种幼胚的成苗率为55%,是前人所用传统胚培方法成功率的5—20倍。杂种幼胚在添加有2 mg/L 2,4-D的MS培养基上诱导为愈伤组织,经继代产生全能性愈伤组织,继而分化出再生植株。愈伤组织经继代保存150天仍不丧失分化能力。本文还对两种产生杂种的组织培养方法进行了比较研究。     

Genome differentiation in Magonoliaceae as revealed from meiotic pairing in interspecific and intergeneric hybrids

The cross compatibility within and between Yulania Spach and Michelia L.(Magnoliaceae) is relatively good and various such hybrids,obtained by conventional artificial hybridization,are available.The aim of the present study was to determine the extent of genome differentiation between the species involved in these crosses through the observation of chromosome pairing during meiosis in pollen mother cells (PMCs) of the hybrids.Chromosome pairing behavior was studied in five species (2n =38) and two interspecific hybrids of Michelia,eight species (2n =38,76 and 114) and 10 interspecific hybrids of Yulania,and three intergeneric hybrids between Michelia and Yulania.The results showed that chromosome pairing was normal with bivalent formation in diploid parental species and in interspecific hybrids.In addition to bivalents,multivalents were encountered in polyploid parental species and polyploid interspecific hybrids.In the intergeneric hybrids between a tetraploid Yulania and two diploid Michelia,19 chromosomes,most likely originating from Michelia,were unable to synapse from zygotene to metaphase I.Meiotic chromosome pairing indicated a high degree of homology between species within Michelia and Yulania and less homology between the genomes of these two genera.The differentiation of morphological characters and the distinctness of natural distribution also support the conclusion that these two genera are likely independent monophyletic groups.This suggests that the two genera were split at early evolution of Magnoliaceae and the overlapping characteristics in external morphology and internal structures of the two genera may be the result of parallel evolution or ancient common ancestry.     

Embryonic lethality leads to hybrid male inviability in hybrids between Drosophila melanogaster and D. santomea

The study of the morphological defects unique to interspecific hybrids can reveal which developmental pathways have diverged between species. Drosophila melanogaster and D. santomea diverged more than 10 million years ago, and when crossed produce sterile adult females. Adult hybrid males are absent from all interspecific crosses. We aimed to determine the fate of these hybrid males. To do so, we tracked the development of hybrid females and males using classic genetic markers and techniques. We found that hybrid males die predominantly as embryos with severe segment‐specification defects while a large proportion of hybrid females embryos hatch and survive to adulthood. In particular, we show that most male embryos show a characteristic abdominal ablation phenotype, not observed in either parental species. This suggests that sex‐specific embryonic developmental defects eliminate hybrid males in this interspecific cross. The study of the developmental abnormalities that occur in hybrids can lead to the understanding of cryptic molecular divergence between species sharing a conserved body plan.     

The influence of temperature on chromosome elimination during embryo development in crosses involving Hordeum spp., wheat (Triticum aestivum L.) and rye (Secale cereale L.)

Summary Several interspecific and intergeneric crosses involving five Hordeum species, Triticum aestivum and Secale cereale were carried out to investigate the influence of two contrasting temperatures on chromosome elimination during embryo development. In four of the interspecific Hordeum crosses, chromosome elimination was significantly increased at the higher of the two temperatures, resulting in greater proportions of haploid plant progenies. However, there was no significant effect of temperature in the other interspecific cross between H. lechleri x H. bulbosum nor in the two intergeneric crosses between H. vulgare x S. cereale and T. aestivum x H. bulbosum whose progeny were exclusively hybrid and haploid, respectively.     

Synchronous allelic expression at the glucosephosphate isomerase A and B loci in interspecific sunfish hybrids

Allelic isozymes of glucosephosphate isomerase at the Gpi-A and -B loci were separated by starch gel electrophoresis in the warmouth (Lepomis gulosus) and green sunfish (L. cyanellus). The specific tissue distributions and developmental expressions of the GPI-A₂, -AB, and -B₂ isozymes were not different between these two species. The synchrony of allelic expression in normal intraspecific sunfish crosses was demonstrated by means of an electrophoretic variant at the Gpi-B locus. In embryos formed from warmouth × green sunfish hybrid crosses, the paternal GPI-A₂ isozymes were first expressed at the same time in both reciprocal hybrids, at 21–25 hr after fertilization. The maternal and paternal GPI-B subunits were synchronously expressed in reciprocal hybrids just prior to hatching. The parental allelic isozymes at both loci showed codominant expression in all tissues of the mature F₁ hybrids. These results are consistent with the absence of allelic asynchrony and inhibition in interspecific hybrids formed from more evolutionarily related species.