祖先性状重建法揭示铁线蕨属植物孢子表面纹饰的形态多样性及其演化

蕨类植物孢子表面的纹饰形态复杂多样, 在分类学和古生物学研究中具有重要意义, 目前探索祖先性状演化常用形态学与系统发育学结合的方法。本文选取一回羽叶铁线蕨类植物为材料, 用扫描电子显微镜观察其孢子形态, 用5个叶绿体基因序列构建系统树, 用最大似然法和最大简约法来分析孢子性状的演化。结果表明: 一回羽叶铁线蕨类的孢子纹饰有5种类型, 即光滑、粗糙、颗粒、疣状及瘤状; 这一类群的祖先孢子纹饰有很大的可能是瘤状纹饰; 疣状纹饰可能是由瘤状纹饰演化而来; 孢子纹饰由简单向复杂演化, 越进化的物种其孢子纹饰越复杂。     

Inheritance of some Mendelian factors in intra- and interspecific crosses between Setaria italica and Setaria viridis

Summary The inheritance of seed coat color, pericarp color, polyphenoloxidase activity and bristle, glume, collar, and leaf-base anthocyanic colorations was investigated using intra- and interspecific crosses between Setaria italica and S. viridis. The results were compared to inheritance results obtained by previous authors. In most cases, the inheritance is simple (one or two loci) and data from different crosses (intra- and interspecific) and from different authors can be compared. Two sets of two characters were found to share common loci: the polyphenoloxidase locus is one of the loci responsible for seed coat color, and bristle and glume color are determined by the same two loci. The evolutionary significance of these results is discussed.     

Different degree of paternal mtDNA leakage between male and female progeny in interspecific Drosophila crosses

Maternal transmission of mitochondrial DNA (mtDNA) in animals is thought to prevent the spread of selfish deleterious mtDNA mutations in the population. Various mechanisms have been evolved independently to prevent the entry of sperm mitochondria in the embryo. However, the increasing number of instances of paternal mtDNA leakage suggests that these mechanisms are not very effective. The destruction of sperm mitochondria in mammalian embryos is mediated by nuclear factors. Also, the destruction of paternal mitochondria in intraspecific crosses is more effective than in interspecific ones. These observations have led to the hypothesis that leakage of paternal mtDNA (and consequently mtDNA recombination owing to ensuing heteroplasmy) might be more common in inter‐ than in intraspecific crosses and that it should increase with phylogenetic distance of hybridizing species. We checked paternal leakage in inter‐ and intraspecific crosses in Drosophila and found little evidence for this hypothesis. In addition, we have observed a higher level of leakage among male than among female progeny from the same cross. This is the first report of sex‐specific leakage of paternal mtDNA. It suggests that paternal mtDNA leakage might not be a stochastic result of an error‐prone mechanism, but rather, it may be under complex genetic control.     

Ultrastructural study of spore wall morphogenesis inOphioglossum thermale kom. var.nipponicum (Miyabe et Kudo) nishida

Spore wall morphogenesis ofOphioglossum thermale var.nipponicum was examined by transmission electron microscopy. The spore wall of this species consists of three layers: endospore, exospore, and perispore. The spore wall development begins at the tetrad stage. At first, the outer undulating lamellar layer of the exospore (Lo) is formed on the spore plasma membrane in advance of the inner accumulating lamellar layer (Li) of the exospore. Next, the homogeneous layer of the exospore (H) is deposited on the outer lamellar layer. Both lamellar layers may be derived from spore cytoplasm; and the homogeneous layer, from the tapetum. Then the endospore (EN) is formed. It may be derived from spore cytoplasm. The membranous perispore (PE), derived from the tapetum, covers the exospore surface as the final layer. Though the ornamentation of this species differs distinctly from that ofO. vulgatum, the results mentioned above are fundamentally in accordance with the data obtained fromO. vulgatum (Lugardon, 1971). Therefore, the pattern of spore wall morphogenesis appears to be very stable in the genusOphioglossum.     

Effect of three pollination methods on embryo development and seedset in intra- and interspecific crosses between seven Lilium species

Summary Interspecific crosses were made between seven Lilium species, viz. L. candidum, L. concolor, L. dauricum, L. henryi, L. longiflorum, L. nepalense and L. rubellum. A complete diallel cross was carried out between these seven species, including self- and intraspecific pollinations using three pollination methods: normal pollination on the stigma, pollination on the ovary after cutting the style, and pollination on the stigma with the aid of mentor (non-functional, compatible) pollen. Embryo rescue, starting 35 days after pollination, was applied to all interspecific combinations. The percentage of successful crosses was about 2.8% after normal pollination, 5.4% after cut-style pollination and 3.8% with the mentor pollen technique. Crosses with L. nepalense were exceptional in that embryos died during the embryo culture phase. Seventeen cross combinations (including 4 reciprocals) yielded 62 embryo plantlets from 839 interspecific pollinations.     

华中铁角蕨孢子纹饰形成的超微结构观察

利用透射电子显微镜对铁角蕨科(Aspleniaceae)华中铁角蕨(Asplenium sarelii Hook.)孢子及其纹饰的形成过程进行观察。结果表明:①华中铁角蕨孢子囊发育为薄囊蕨型;②孢子外壁表面光滑,远极面的外壁厚约0.8~1.1μm,近极面的外壁厚约1.4~1.8μm;③孢子周壁厚度约4~5μm,染色较外壁深,分为内层和外层;内层紧帖外壁表面,其上具柱状、瘤状或疣状突起;外层向外隆起形成脊状纹饰的轮廓,脊的下方具空腔,脊的顶端具翅;④铁角蕨型与鳞毛蕨型孢子外壁和周壁纹饰的形成过程具有相似性;⑤孢子的成熟度对于孢子形态的研究是至关重要的,只有完全成熟的孢子的表面纹饰才是稳定的。     

Self-incompatibility and interspecific incompatibility: relationships in intra- and interspecific crosses of Zinnia elegans Jacq. and Z. angustifolia HBK (Compositae)

Summary Intraspecific and reciprocal interspecific crosses involving Zinnia angustifolia clones and Z. elegans lines showed that in both species, sporophytic self-incompatibility (SI) systems were present. Intensity of SI varied among clones and lines, and high self seed set was associated with a concomitant decrease in callose fluorescence in papillae and pollen tubes. Incomplete stigmatic inhibition of pollen germination and tube growth was observed in reciprocal interspecific crosses and associated with callose synthesis, suggesting S-gene activity. Seed set and progeny obtained following Z. angustifolia×Z. elegans matings was comparable to intraspecific compatible matings of Z. angustifolia although the rate of pollen tube growth through the style was slower. In Z. elegans × Z. angustifolia matings, additional prezygotic barriers were present and acted between pollen tube penetration of the stigma and syngamy. SI X SI interspecific incompatibility was essentially unilateral, with no embryos or progeny obtained when Z. elegans was the pistillate parent. It was hypothesized that nonfunctioning of Z. elegans × Z. angustifolia crosses was due to S-gene expression at the stigmatic surface and to other isolating mechanisms in the stylar or ovarian transmitting tissue.Scientific Article No. A-4448, Contribution No. 7439 of the Maryland Agricultural Experiment Station, Department of HorticultureA portion of this paper was presented in the report: Boyle TH, Stimart DP (1986) Incompatibility relationships in intra- and interspecific crosses of Z. elegans Jacq. and Z. angustifolia HBK (Compositae). In: Mulcahy D (ed) Biotechnology and ecology of pollen. Springer, New York     

Fine structure of resting spore formation and germination in Entomophthora virulenta

The fine structure during the formation and germination of resting spores of Entomophthora virulenta is described. There were many microbodies in contact with oil droplets, and the microbodies appeared to participate in spore germination. The mature resting spore had an epispore layer with two regions and an endospore layer with five regions. Dictyosomes, numerous vesicles, and lomasomes were produced during the formation of the endospore layer. Prior to spore germination, the single large oil droplet separated into numerous small oil droplets, and the new cell wall was formed beneath the endospore layer which gradually disintegrated possibly by enzymatic actions. The germ tube perforated the epispore layer mainly by mechanical pressure.     

Facies dependence of spore assemblages and new data on sedimentary influence on spore taphonomy

Palynological studies have been undertaken on Lower Carboniferous (Mississippian) rocks encountered in boreholes from the North Sea to the Baltic Sea (Rügen) in Northern Germany and from an outcrop at the northern border of the Rhenish Slate Mountains in western central Germany. The studied sections belong to different facies realms within the neritic shelf facies. They begin with very near shore coastal clastic facies in the North Sea and onshore Northern Germany, ranging into carbonate platform facies at Rügen, and then into platform slope facies at the northern margin of the Rhenish Slate Mountains. The focus of this study is the analysis of the relationship between sedimentary facies and spore assemblages; therefore, spores were considered only as sedimentary particles. Thus, it was necessary to create a new spore classification scheme based only on relevant sedimentary features. The new scheme distinguishes three classes of miospore based on shape, with each class subdivided into three subclasses based on features of ornament. The diversity of the spore assemblages and the total palynofacies have also been studied. Correlating palynological results from sections representing different sedimentary facies has led to a better understanding of the influence of sedimentary facies on spore assemblages. Correlations have been made at two stratigraphical levels. Regional correlation is undertaken on the Upper Viséan from the coastal clastic facies (North Sea, Northern Germany), the carbonate platform facies (Rügen) and the marginal platform slope facies (Velbert). Local correlation within the carbonate platform facies has been attempted using samples of Mid-Viséan TS zone from four boreholes on Rügen. Certain important differences have been observed. The local correlation at Rügen shows a decrease in spore frequency and spore assemblage diversity related to increasing resedimentation within subsided blocks of the platform. The composition of spore assemblages, strongly dominated by round-shaped spores, is nearly the same in all sections. The regional correlation shows clear proximal–distal trends for the total number of spores and also the diversity and composition of spore assemblages. A strong decrease in triangular and transitional spores from proximal to distal facies was observed. In conclusion, spore assemblages seem to be strongly influenced by sedimentary facies as well as by different sedimentary processes within the facies. Facies dependence of spore assemblages is shown to be an important factor for stratigraphical use of spores and for establishing vegetational and climatic trends.     

Effects of modification of membrane lipid composition on Bacillus subtilis sporulation and spore properties

Aims: To determine effects of inner membrane lipid composition on Bacillus subtilis sporulation and spore properties. Methods and Results: The absence of genes encoding lipid biosynthetic enzymes had no effect on B. subtilis sporulation, although the expected lipids were absent from spores’ inner membrane. The rate of spore germination with nutrients was decreased c. 50% with mutants that lacked the major cardiolipin (CL) synthase and another enzyme for synthesis of a major phospholipid. Spores lacking the minor CL synthase or an enzyme essential for glycolipid synthesis exhibited 50–150% increases in rates of dodecylamine germination, while spores lacking enzymes for phosphatidylethanolamine (PE), phosphatidylserine (PS) and lysylphosphatidylglycerol (l‐PG) synthesis exhibited a 30–50% decrease. Spore sensitivity to H₂O₂ and tert‐butylhydroperoxide was increased 30–60% in the absence of the major CL synthase, but these spores’ sensitivity to NaOCl or Oxone^? was unaffected. Spores of lipid synthesis mutants were less resistant to wet heat, with spores lacking enzymes for PE, PS or l‐PG synthesis exhibiting a two to threefold decrease and spores of other strains exhibiting a four to 10‐fold decrease. The decrease in spore wet heat resistance correlated with an increase in core water content. Conclusions: Changing the lipid composition of the B. subtilis inner membrane did not affect sporulation, although modest effects on spore germination and wet heat and oxidizing agent sensitivity were observed, especially when multiple lipids were absent. The increases in rates of dodecylamine germination were likely due to increased ability of this compound to interact with the spore’s inner membrane in the absence of some CL and glycolipids. The effects on spore wet heat sensitivity are likely indirect, because they were correlated with changes in core water content. Significance and Impact of the Study: The results of this study provide insight into roles of inner membrane lipids in spore properties.     

新疆裂叶苔科11种植物孢子、弹丝和油体的形态观察

为了完善有关裂叶苔科植物孢子、弹丝和油体的研究,为该科植物的分类提供详细的资料,利用光学显微镜和扫描电镜观察裂叶苔科（Lophoziaceae）11种植物的孢子、弹丝和油体的形态特征,其中有6种具备了孢子和弹丝的形态特征,9种具备了油体的形态特征。结果表明：(1)裂叶苔科的6种植物的孢子为球形、近球形和椭圆形;颜色为褐色、红褐色和黄褐色;直径在10～16μm,属于小型孢子（MI）;近极面向内凹,纹饰为疣状、棍棒状、刺状、颗粒状和短棒状。(2)弹丝均为紧密双螺旋状,两端圆钝,表面平滑或具稀的颗粒2种。(3)裂叶苔科的9种植物的油体形状为球形、椭圆形、球形或卵形,直径在3～10μm。本研究对这11种植物的孢子、弹丝和油体进行了详细的描述并附图示,为裂叶苔科植物的系统分类、演化研究提供基础资料。     

黄果厚壳桂种内与种间竞争的数量关系

采用Hegyi单木竞争指数模型对鼎湖山季风常绿阔叶林建群种黄果厚壳桂的种内、种间竞争强度进行定量分析.结果表明,黄果厚壳桂所受到的竞争强度随着林木径级的增大而逐渐减小.黄果厚壳桂种内竞争较与伴生树种云南银柴的种间竞争弱.黄果厚壳桂种内和种间竞争强度的顺序为:云南银柴>黄果厚壳桂种内>荷木>白颜树>肖蒲桃>锥栗>红车>臀形果>柏拉木>水石梓>窄叶半枫荷>厚壳桂.整个林分及黄果厚壳桂种内竞争木对对象木的竞争强度与对象木的胸径大小之间的关系近似服从幂函数关系,而伴生树种竞争木对对象木的竞争强度与对象木的胸径大小之间的关系近似服从对数函数关系.竞争强度和对象木的胸径大小呈显著负相关关系.     

国家自然科学基金孢子植物经典分类项目资助概况和研究进展

基于对国家自然科学基金委员会植物学科近五年来资助的孢子植物经典分类项目的结题报告、年度进展报告及申请书的整体分析,本文简单介绍了“经典分类倾斜项目”的资助情况和取得的主要研究成果和进展。     

Pollen exine ornamentation in the F2 generation of an interspecific hybrid of Chorisia (Bombacoideae,Malvaceae) in relation to inheritance pattern

Pollen morphology in ten plants of F₂ progeny of an interspecific tree hybrid, Chorisia insignis H. B.& K.×C. speciosa St. Hil (Bombacoideae, Malvaceae) has been studied with a view to have an insight in to the effect of hybridization on the pollen morphological features in F₂ generation. The study is a sequel to an earlier study on the pollen morphology of Chorisia species and their F₁ hybrid, in which case the hybrid pollen uniformly exhibited the apertural features of the male parent and exine features of the female parent. In the F₂ progeny the pollen grains display the apertural feature of the male parent in all the plants. However, with regard to exine ornamentation, variability has been observed. Of the ten plants, two plants exhibit the exine features of the male parent showing empty lumina (without bacula), five plants have their pollen exactly like that of the F₁ plant (showing prominent columellar heads in the lumina of the apocolpium region) and the remaining three plants showing columellae in lumina of both apocolpium and mesocolpium region being different from the above types. It has been inferred that the variability in the exine pattern in F₂ pollen indicates that the pollen exine pattern in hybrids, perhaps, is not unequivocally controlled by sporophytic or gametophytic genomes.     

广西石韦属七种植物叶片结构与孢子形态的比较研究

利用石蜡切片法研究了石韦属7种植物叶片的形态结构。结果显示:7种植物的叶片均属异面叶,且具典型的旱生叶结构;表皮大多为复表皮,表皮细胞排列紧密,主脉表面覆有厚角质膜,表皮毛为星状毛,由多细胞组成;气孔集中分布于下表皮,气孔类型为围绕型,气孔器略下陷;孢子两侧对称,极面观椭圆形,赤道面观豆形或超半圆形,表面饰纹为瘤状饰纹。石韦属7种植物的叶表皮细胞形状、表皮毛、表皮细胞垂周壁式样、气孔密度等解剖结构均表现出一定的种间差异,这些特征可为石韦属植物种间分类提供依据。     

Fertilization and early embryo development in reciprocal interspecific crosses of Phaseolus

Summary Fertilization and early embryo and endosperm development were examined in Phaseolus vulgaris x P. acutifolius, P. vulgaris x P. lunatus crosses and their reciprocals. The number and length of pollen tubes were not different between selfings and interspecific crosses. Fertilization was completed in all matings and the time of fertilization was maternally dependent which may reflect the degree of maturation of embryo sacs at pollination. A large difference between reciprocal crosses was found in the time of endosperm and embryo division in relation to the time of fertilization. When P. vulgaris was the female parent and P. acutifolius the male parent, endosperm division occurred at the same time as in P. vulgaris upon selfing, while in P. vulgaris x P. lunatus crosses the time of endosperm division was intermediate as compared with the two parents. The time lapse between fertilization and endosperm and embryo division in P. acutifolius x P. vulgaris crosses was longer than in either parent upon selfing. In P. lunatus x P. vulgaris crosses, endosperm division occurred in only 7–12% of the ovules at 72 hours after pollination. Embryo development in these ovules was limited to the four cell stage although the endosperm was at the free nuclei stage. The severe delay in embryo and endosperm divisions may be the major cause of early pod abscission in P. lunatus x P. vulgaris crosses.Technical paper No. 4929 of the Oregon Agricultural Experiment Station. Research was supported by the Oregon Agricultural Experiment Station, the Research Council of Oregon State University (NIH Biomedical Research Support Grand RR07079) and the Processor Research Council of Oregon. A.R. is supported by an African Graduate Fellowship from the African-American Institute.