泽苔草的花器官发生

本文用扫描电镜观察了泽苔草的花器官发生过程,观察结果表明：花萼以螺旋状方式向心发生,花瓣以接近轮状方式近同时发生,不存在花瓣雄蕊复合原基。雄蕊和心皮均以轮状向心方式发生,6枚雄蕊分两轮分别在对萼和对瓣的位置先后发生,至发育的后期排成一轮,但仍分别处于对萼和对瓣的位置;随后发生的第一轮3个心皮原基与3枚萼片相对,第二、三轮心皮原基分别为1~3个,与前一轮心皮相间排列向心发生。本文首次揭示了泽苔草花被的外轮3个萼片螺旋状发生方式,这种螺旋状方式很可能是泽泻科植物的花部结构在进化过程中适应环境而保留下来的一种较原始的叶性特征。     

长喙毛茛泽泻（泽泻科）的交配系统研究

对濒凶植物长喙毛茛泽泻的交配系统作了综合研究。结果理：该种的花粉粒和柱头较平滑,花内分泌细胞存在但欠发达,开花前花粉萌发率较高而开花１ｈ后花粉萌发能力急剧衰退,花粉／胚珠比较低,花部综合特征与其花前期闭花授粉的交配习性相适应。该种的自然居群及实验居群中均未观察到花间的虫媒传粉,仅有极小型昆虫起花内传粉作用,亦未检出风媒花粉流。     

矮慈姑的传粉机制与交配系统

对矮慈姑（ＳａｇｉｔａｒｉａｐｙｇｍａｅａＭｉｑ）的传粉过程与花粉流作了观察,用同工酶遗传标记法对其一个自然居群的异交率作出定量估计。在自然及人工居群中均观察到虫媒传粉,其中有较大比例的近距离传粉。未检出风媒花粉流。自交可育,同时存在雌雄同株和花序内雌雄花异熟等异交机制。异交率估计结果（ｔ＝４９９％）表明其交配系统为异交／自交兼性系统。作者认为,其较大比例的自交应归因于同株之不同克隆分株间交配的频繁发生     

木耳交配型混合集群RAPD分析

用ＲＡＰＤ－混合集群分析来检测异宗结合担子菌不同交配型间的多态性。来源于同一木耳Ａｕｒｉｃｕｌａｒｉａ ａｕｒｉｃｕｌａ （Ｌ．ｅｘ Ｈｏｏｋ．）Ｕｎｄｅｒｗ．子实体的１０个单孢萌发而成的单核体进行ＲＡＰＤ分析证实,它们之间具有极高的同源性。将单核体按其所属的交配型分为两类,每类各５个,构成Ａ１,Ａ２两个基因池。用３３种单引物,２０种双引物对其进行扩增、分析,发现引物ＯＰＥ１９号能在这两个基因池间     

厦门木麻黄种群交配系统及近交衰退

木麻黄耐沙生,盐碱,是沿海优良的防护林树种,从20世纪80年代开始,木麻黄林呈现出衰退现象。采用等位酶分析技术研究木麻黄种群的交配系统及近交衰退,木麻黄种群异交率为0．622,表明为混合酱类型,与其亲缘种比较来看,引种降低了木麻黄异交率,增加了近交,采用电是接估算的近交衰退程度很高。结果表明,引种过程中的建立者效应引起的近交及其后的近交衰退确定在木麻黄林衰退中起了重要作用,根据基因型有选择地引起木麻黄以减轻衰退。     

木耳交配型混合集群RAPD分析

用RAPD-混合集群分析来检测异宗结合担子菌不同交配型间的多态性。来源于同一木耳Anriculariaauricula（L．exHook．）Underw,子实体的10个单孢萌发而成的单核体进行RAPD分析证实,它们之间具有极高的同源性。将单核体按其所属的交配型分为两类,每类各5个,构成A1,A2两个基因池。用33种单引物,20种双引物对其进行扩增、分析,发现引物OPE19号能在这两个基因池间产生多态性,其中一条特异性谱带在A2基因池扩增产物中存在,在A1基因池中不存在。推测这一条谱带可能是与A2交配型基因连锁的分子标记。此研究结果不仅为由单因子控制的二极性担子菌的交配型测定提供科学依据,而且为RAPD技术在异宗结合担子菌极性研究中的应用展示了可喜的前景。     

木耳交配型混合集群RAPD分析*

用RAPD_混合集群分析来检测异宗结合担子菌不同交配型间的多态性。来源于同一木耳 Auricularia auricula (L. ex Hook．) Underw．子实体的10个单孢萌发而成的单核体进行RAPD分析证实,它们之间具有极高的同源性。将单核体按其所属的交配型分为两类,每类各5个,构成A1,A2两个基因池。用33种单引物,20种双引物对其进行扩增、分析,发现引物oPE19号能在这两个基因池间产生多态性,其中一条特异性谱带在A2基因池扩增产物中存在,在A1基因池中不存在。推测这一条谱带可能是与A2交配型基因连锁的分子标记。此研究结果不仅为由单因子控制的二极性担子菌的交配型测定提供科学依据,而且为R们技术在异宗结合担子菌极性研究中的应用展示了可喜的前景。     

珍稀水生植物——宽叶泽苔草的核型研究

宽叶泽苔草（Caldesia granis Samuel）。是一种珍稀濒危水生植物。它曾经一度被认为已经从中国大陆灭绝,但最近又在湖南省的一个高山沼泽中被发现。本文首次报道了依据上述新发现地点的宽叶泽苔草材料进行的细胞学研究结果。核型分析结果表明：本种染色体数目为22,其染色体组型高度不对称。结合前人对宽叶泽苔草一些近缘种的细胞学及古生物学研究结果,作者认为泽苔草属植物很可能是泽泻科中最进化的一个属。     

植物交配系统及其在植物保护中的应用

植物交配系统是影响植物居群遗传结构最关键的生物学因素之一。在具体实践中,对遗传育种方法的选择和植物保护策略的制定具有指导意义。本文回顾了植物交配系统的研究历史,分析了相关概念,讨论了植物交配系统的变异与进化,介绍了相关的基本原理和研究方法,对研究中使用的分析工具作了比较。对国内外植物交配系统研究的进展,讨论了在实际研究中的取样及针对不同植物的保护策略问题,强调了植物交配系统信息在植物保护中的重要性,认为在植物保护中应加强植物交配系统的研究。     

中国苔草属二柱苔草亚属的系统总览及植物地理学的研究

本文对我国苔草属二柱苔草亚属Subgen．Vignea作了系统排列,并提出以下几点的看法： 1．二柱苔草亚属是苔草属中比较自然的一个类群,我国有48种、7亚种和1变种,隶属于16个组。根据Takhtajan的世界植物区划,将它们分成4种成分,即：(1)环北方植物地区成分,占总数的20．4％;(2)东亚植物地区成分,占总数的55.5％。实际上,只有4个分类群出现于中国-喜马拉雅森林植物亚区,而其余的都均分布于中国-日本森林植物亚区,并且在这一亚区内有8个特有成分,占特有成分总数的61.5％;显然,中国二柱苔草亚属在中国-日本森林植物亚区内的分化较其他地区更为强烈;(3)伊朗—吐兰植物地区成分,占总数的16.7％;(4)印度支那植物地区成分和印度植物地区成分,占总数的7.4％。 2．高节苔草C．thomsonii和云雾苔草C．nubigena类群是Subgen．Vignea中较为原始的种类,它们为印度支那植物地区和印度植物地区成分。这样非但Subgen．Indocarex原始类群分布于东南亚和马来西亚,而Subgea．Vignea的原始类群也分布于东南亚,这也是对Nelmes提出Carex起源于印度-马来西亚地区的一个佐证。     

The mating system in natural and shelterwood stands of Douglas-fir

Summary Mating systems in two pairs of old-growth uncut and adjacent shelterwood stands of Douglas-fir (Pseudotsuga menziesii var. menziesii) were compared by estimating the proportions of viable progenies due to outcrossing (t) with both single-locus and multilocus techniques. Single-locus population estimates (_s), ranging from 0.41 to 1.16, were significantly (P<0.05) heterogeneous among loci in three of four stands; mean single-locus estimates for shelterwoods were not significantly different from those for uncut stands. Multilocus population estimates (_m) ranged from 0.94 to 1.00; again, estimates for shelterwoods were not significantly different from those for uncut stands. Multilocus estimates were slightly higher than mean single-locus estimates for uncut stands but were nearly equivalent for shelterwoods, suggesting that related matings other than selfs may be associated with uncut stands, but not shelterwoods. Individual-tree outcrossing rates (_{m i}), estimated for six trees in each shelterwood, ranged from 0.90 to 1.10 and were significantly heterogeneous among trees at one of the two shelterwoods. Outcrossing was high (> 0.90) in both uncult and shelterwood stands, and no evidence indicated that low parent-tree density had affected stand outcrossing rates.FRL 1918, Forest Research Laboratory. Oregon State University, Corvallis, USA     

小慈姑的开花状态、传粉机制与交配系统

在自然种群中对沼生植物小慈姑（Sagittaria potamogetifolia Merr.）的开花状态和传粉过程作了观测,并用同工酶遗传标记法定量估测了其3个种群中5个样本的异交率。该种为中心媒传粉为主的虫／风 媒兼性传粉机制,访花昆虫的飞行距离多在0-2m范围内,并与花序密度呈不显著的正相关。异交率（－／^／t）为50.0％－92.8％,表明该种为异交为主的混合交配系统（ixed mating system）。对雌雄同株的小慈姑而言,异交率与各种群花期植株密度无关,异交水平取决于种群中开花花序的两个或两个以上的植株所占比例。     

Quantitative studies on the mating system of opium poppy (Papaver somniferum L.)

Summary Nearly 400 individuals at two locations and over a number of years were crossed and subsequently scored for selfing versus outcrossing in eight monohybrid populations of opium poppy (Papaver somniferum). Two different marker loci, petal colour (R/r) and capsule size (B/b) were used to determine the male gametes that had effected fertilizations in F₂ recessives (rr and bb). The estimates of the outcrossing parameter were found to vary with year, location and for the marker locus used ( range: 0.0988–0.3704). Study of two dihybrid crosses involving the two loci simultaneously, further confirmed that outcrossing at the R/r locus was significantly greater than that at the B/b locus. The nature of the outcrossing was, in general, nonrandom. Selfmg predominated in this species; however, there was a high frequency of natural outcrossing for generating variations in P. somniferum.CIMAP publication No. 1086     

Asexual reproduction does not produce clonal populations of the brooding coral Pocillopora damicornis on the Great Barrier Reef, Australia

We have investigated the relationship between genotypic diversity, the mode of production of brooded larvae and disturbance in a range of reef habitats, in order to resolve the disparity between the reproductive mode and population structure reported for the brooding coral Pocillopora damicornis. Within 14 sites across six habitats, the ratio of the observed (G _o) to the expected (G _e) genotypic diversity ranged from 69 to 100% of that expected for random mating. At three other sites in two habitats the G _o /G _e ranged from 35 to 53%. Two of these sites were recently bleached, suggesting that asexual recruitment may be favoured after disturbance. Nevertheless, our data suggest that brooded larvae, from each of five habitats surveyed, were asexually produced. While clonal recruitment may be important in disturbed habitats, the lack of clonality detected, both in this and earlier surveys of 40 other sites, implies that a disturbance is normally insufficient to explain this species’ continued investment in clonal reproduction.     

克隆植物的无性与有性繁殖对策

许多植物同时具有克隆生长与有性繁殖,两种繁殖方式间的平衡在不同物种间以及同一物种内不同种群间变化很大。旺盛的克隆生长可能会从多方面影响生活史进化。首先,许多克隆植物的有性繁殖与更新程度都很低,甚至有一些植物由于克隆生长而几乎完全放弃了有性过程,从而影响到克隆植物对局域环境的适应和地理范围进化。其次,克隆生长增大花展示进而增加了对传粉者的吸引,同时也增加了同株异花授粉的风险,而同株异花授粉往往会导致植物雄性和雌性适合度的下降。因此,克隆植物的空间结构与交配方式间可能存在着协同进化关系。最后,克隆生长与有性繁殖间可能存在着权衡关系:对克隆生长的资源投入将会减少对有性繁殖的资源投入。这种权衡关系可能是由环境条件、竞争力度、植物寿命和遗传等因素决定的。如果不同的繁殖方式是植物在不同环境下采取的适应性对策,那么我们可以预期:在波动和竞争力度大的生境中,植物应将大部分的繁殖资源分配给有性繁殖;而在相对稳定的环境中,克隆繁殖应该占据优势地位。但是自然选择对两种繁殖方式的选择结果是什么,以及控制这两种方式间平衡的生态和遗传因子究竟有哪些,到底是克隆生长单向地影响了植物的有性繁殖,还是与有性过程相伴随的选择压力同时塑造了植物的克隆习性?目前尚不清楚。同时从无性与有性繁殖两个方面综合考察克隆植物的繁殖对策是今后亟待加强的工作。     

The evolution of self-compatible and self-incompatible populations in a hermaphroditic perennial, <Emphasis Type="Italic">Trillium camschatcense</Emphasis> (Melanthiaceae)

The evolution of selfing from outcrossing ancestors is known to have occurred repeatedly in angiosperms. Theoretical studies have argued that the transition from outcrossing to selfing is accomplished more easily than the reverse case, and phylogenetic analyses involving self-compatible (SC) and self-incompatible (SI) species has basically supported this assumption. The evolutionary direction of self-compatibility and self-incompatibility was examined in Trillium camschatcense, which contains geographically widespread SC populations, and restricted SI populations. Ecological surveys have revealed that the SC populations were suitable for outcrossing, and selfing in these populations did not confer any fitness advantage. Since reproductive fitness indicates the possibility of an evolutionary shift from self-compatibility to self-incompatibility, the phylogenetic relationships of SI and SC populations of T. camschatcense were investigated based on cpDNA variations and nuclear DNA microsatellite polymorphisms. Although phylogenetic analyses did not provide credible evidence to determine evolutionary direction, the SI populations turned out to be monophyletic with extremely low genetic differentiation. Based on these results, we proposed two possible scenarios for the evolutionary backgrounds of SI and SC populations in T. camschatcense. The plausibility of each scenario was evaluated based on the reproductive and geographical features of the mating systems. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Propagule size is not a good predictor for regional population subdivision or fine-scale spatial structure in lichenized fungi

Propagule size has important consequences on the genetic structure of wind-dispersed species, as species with small propagules have higher capability of long-distance dispersal. Here, we studied reproductive modes and compared local and regional population structures in three Macaronesian lichenized fungi differing in propagule size. First, we quantified size distribution of propagules in each species. Second, genotype simulations based on microsatellite data were used to infer the reproductive mode. Third, using spatial analysis and population genetic approaches, we quantified the local and regional scale genetic structures of the fungal species. The three species differed in size distributions of propagules. The majority of populations exhibited clonal reproductive mode. Identical reproductive modes occurred often across species in the same sites, implying a possible relationship between reproductive mode and local site conditions. Contrary to expectation, at the local scale, the species exhibited similar patterns of spatial autocorrelation in genotypes. However, in agreement with the expectation based on propagule size, the species with highest frequency of small vegetative propagules (L. pulmonaria) exhibited lowest regional genetic differentiation. Nevertheless, altogether, our results show that propagule size is not a good predictor of population subdivision in lichenized fungi, neither at local nor regional spatial scale.