The Morphology and Significance of the Spermoviduct and Prostate in the Evolution of the Reproductive System of the Pulmonata

The purpose of this paper is twofold: (1) to review the reproductive systems of the pulmonates in order to determine the inherent trends displayed by this system in these animals. The different elements composing this system, especially those of the pallial region, are homologised and the functional aspects (s. 1.) of the components described, including the origin and evolutionary development of the various prostatic elements of the pulmonates; and (2) to review ideas on and discuss the origin of the hermaphroditism of the pulmonate reproductive systems.     

Evolution of Reproductive Organs in Land Plants

LEAFY gene is the positive regulator of the MADS-box genes in flower primordia. The number of MADS-box genes presumably increased by gene duplications before the divergence of ferns and seed plants. Most MADS-box genes in ferns are expressed similarly in both vegetative and reproductive organs, while in gymnosperms, some MADS-box genes are specifically expressed in reproductive organs. This suggests that (1) the increase in the number of MADS-box genes and (2) the subsequent recruitment of some MADS-box genes as homeotic selector genes were important for the evolution of complex reproductive organs. The phylogenetic tree including both angiosperm and gymnosperm MADS-box genes indicates the loss of the A-function genes in the gymnosperm lineage, which is presumably related to the absence of perianths in extant gymnosperms. Comparison of expression patterns of orthologous MADS-box genes in angiosperms, Gnetales, and conifers supports the sister relationship of Gnetales and conifers over that of Gnetales and angiosperms predicted by phylogenetic trees based on amino acid and nucleotide sequences. Received 30 July 1999/ Accepted in revised form 9 September 1999     

Leaf Heteroblasty in Pseudopanax crassifolius: Functional Significance of Leaf Morphology and Anatomy

Pseudopanax crassifolius (A. Cunn.) C. Koch. is a strongly heteroblastictree indigenous to New Zealand. Changes in the morphology andanatomy of leaves are described for seedling, juvenile, transitionaland adult phases of development. Seedlings produce five leaftypes; all are relatively small, thin, anthocyanic, have a lowspecific weight, and are anatomically comparable to the leavesof many shade plants. Juvenile leaves are long, linear, deflexed,coriaceous and sharply-toothed. They have a high specific weight,a thick, ornamented cuticle, a multiseriate hypodermis composedof collenchyma, well developed palisade and many spongy mesophylllayers. Juvenile leaves are strong relative to adult leavesand to the leaves of other species. Leaf strength is providedby fibres associated with the midrib. Adult leaves are shorter,broader and less massive than juvenile leaves, and are orientedhorizontally. Transitional leaves are morphologically intermediatebetween juvenile and adult leaves. The anatomy of juvenile,transitional and adult leaves is similar. The heteroblasticseries may be associated with changes in leaf construction costs,light interception and heat dissipation.Copyright 1993, 1999Academic Press Lancewood, Pseudopanax crassifolius (A. Cunn.) C. Koch., leaf heteroblasty, anatomy, morphology, structural adaptations     

Leaf Survival and Evolution in Betulaceae

Studies on the changes in leaf number of 12 species of Betulaceaewere carried out by repeated observations during several years.The inner structure of the winter buds of these species wasalso examined. The periods of leaf emergence were long in Alnusand Betula, intermediate in Corylus and short in Ostrya andCarpinus. A heavy summer leaf fall is characteristic only ofthe Gymnothyrsus subgenus of Alnus. One lamina and two stipulesis the basic unit constituting the winter buds. Only the budsof Gymnothyrsus are composed of several of these units. In theAlnaster subgenus of Alnus, Betula and Corylus, there are oneor two scales that seem to have originated from the two stipulesremaining after reduction of the lamina. Eight and 24 scalesof similar origin were found in Ostrya and Carpinus respectively.A common ancestral species having the following primitive charactersis proposed: shoot constituted only of the equal-sized units,period of leaf emergence long, and leaf fall usually occurs.Alnus (Gymnothyrsus) is assumed to be the most primitive typeas it has many characters similar to those of the proposed ancestralspecies. Carpinus is assumed to be the most advanced group.The leaf survivorship curve is assumed to have changed fromthe primitive bell-shaped to an advanced trapezoid concurrentwith an increase in the number of bud scales. Betulaceae, Alnus, Betula, Carpinus, Corylus, Ostrya, leaf survival, leaf emergence, stipules, winter buds, evolution     

Quantitative Morphology of the Developing Cucumber Leaf

Leaves were harvested from cucumber plants (Cucumis sativuscv. Butchers' Disease Resister) grown at 27 C in controlledenvironments. Gompertz and logistic curves fitted lamina lengthdata well, but Gompertz were found to be more useful. The averageintervascular interval increased from approx. 0.1–0.4mm during leaf development. The average maximum number of cellsthrough or around which material had to pass between mesophyllcells and the vascular system was approx. 7 and varied little,supporting the hypothesis that veins develop so as not to allowthis number of cells to exceed a critical value. Cucumis sativus, cucumber leaf, growth analysis, Gompertz, cell number, vein, vein length, transport     

Models of Evolution of Reproductive Isolation

Mathematical models are presented for the evolution of postmating and premating reproductive isolation. In the case of postmating isolation it is assumed that hybrid sterility or inviability is caused by incompatibility of alleles at one or two loci, and evolution of reproductive isolation occurs by random fixation of different incompatibility alleles in different populations. Mutations are assumed to occur following either the stepwise mutation model or the infinite-allele model. Computer simulations by using It?'s stochastic differential equations have shown that in the model used the reproductive isolation mechanism evolves faster in small populations than in large populations when the mutation rate remains the same. In populations of a given size it evolves faster when the number of loci involved is large than when this is small. In general, however, evolution of isolation mechanisms is a very slow process, and it would take thousands to millions of generations if the mutation rate is of the order of 10(-5) per generation. Since gene substitution occurs as a stochastic process, the time required for the establishment of reproductive isolation has a large variance. Although the average time of evolution of isolation mechanisms is very long, substitution of incompatibility genes in a population occurs rather quickly once it starts. The intrapopulational fertility or viability is always very high. In the model of premating isolation it is assumed that mating preference or compatibility is determined by male- and female-limited characters, each of which is controlled by a single locus with multiple alleles, and mating occurs only when the male and female characters are compatible with each other. Computer simulations have shown that the dynamics of evolution of premating isolation mechanism is very similar to that of postmating isolation mechanism, and the mean and variance of the time required for establishment of premating isolation are very large. Theoretical predictions obtained from the present study about the speed of evolution of reproductive isolation are consistent with empirical data available from vertebrate organisms.     

黑龙江椴树属植物叶表皮形态学观察

利用扫描电子显微镜对紫椴（Tilia amurensis Rupr.）及糠椴（T. mandshurica Rupr.et Maxim.）叶片的微观形态结构特征进行观察,并进行微观形态结构的比较研究。研究结果表明紫椴与糠椴叶片上表皮微观形态相同,而下表皮气孔器的形态类型、蜡质纹饰和角质膜的形态特征、单位面积上星状毛的数量均表现出很大的差异。这些微观形态差异可作为区分紫椴和糠椴的分类学依据。     

Morphology of Male Reproductive Systems in Ephemeroptera: Intrinsic Musculature

Although the Ephemeroptera have been studied over a long period of time, there are still few studies on the morphology of male reproductive system. The spermatic ducts are considered conserved among different Ephemeroptera groups. However, previous studies distinguished different organizational patterns of the spermatic duct intrinsic musculature. This study describes the morphology of the spermatic ducts, especially their musculature, in six species of Ephemeroptera, representing five families. We have observed variations in the organizational pattern of the spermatic ducts, even between species from the same family. Moreover, all species studied had intrinsic musculature in the spermatic ducts although with different organizational patterns. Thus, we believe that this musculature is important to move the spermatozoa along the ducts of all Ephemeroptera and not only of those with aflagellated spermatozoa (Leptophlebiidae). The variations in musculature organization must be related to differences in reproductive physiology (i.e., copula duration) and not only with spermatozoa characteristics.     

长蛸生殖系统的形态学与组织学观察

运用解剖学和组织学方法对长蛸(Octopus variabilis)生殖系统的形态结构进行了研究.结果表明,长蛸雌雄异体并异形,雄性右侧第三腕茎化.长蛸雌性生殖系统由一个卵巢、成对的输卵管及输卵管腺组成.卵巢壁上发出一条线状具分支的生殖索,米粒状的滤泡以卵柄连接至生殖索上.每个滤泡是由单层滤泡细胞围绕着一个卵母细胞构成.输卵管形成丰富的纵行褶皱,黏膜上皮具有纤毛.输卵管腺含有两种类型腺细胞.雄性生殖系统包括精巢、输精管前段、储精囊、摄护腺、盲囊、输精管后段和精荚囊.精巢内部被结缔组织分隔成许多精小叶,精原细胞由小叶壁中的生殖上皮产生,并向小叶腔中逐步分化成精子.输精管前段、盲囊和摄护腺所分泌的黏液物质共同参与精荚的形成.储精囊和输精管后段形成较多的纵行褶皱,输精管后段上皮游离面的纤毛可运输生殖细胞.精荚囊的作用则是贮存精荚,囊壁中的平滑肌利于长蛸交配时精荚的排出.     

Light-Induced Indeterminacy Alters Shade-Avoiding Tomato Leaf Morphology

Plants sense the foliar shade of competitors and alter their developmental programs through the shade-avoidance response. Internode and petiole elongation, and changes in overall leaf area and leaf mass per area, are the stereotypical architectural responses to foliar shade in the shoot. However, changes in leaf shape and complexity in response to shade remain incompletely, and qualitatively, described. Using a meta-analysis of more than 18,000 previously published leaflet outlines, we demonstrate that shade avoidance alters leaf shape in domesticated tomato (Solanum lycopersicum) and wild relatives. The effects of shade avoidance on leaf shape are subtle with respect to individual traits but are combinatorially strong. We then seek to describe the developmental origins of shade-induced changes in leaf shape by swapping plants between light treatments. Leaf size is light responsive late into development, but patterning events, such as stomatal index, are irrevocably specified earlier. Observing that shade induces increases in shoot apical meristem size, we then describe gene expression changes in early leaf primordia and the meristem using laser microdissection. We find that in leaf primordia, shade avoidance is not mediated through canonical pathways described in mature organs but rather through the expression of KNOTTED1-LIKE HOMEOBOX and other indeterminacy genes, altering known developmental pathways responsible for patterning leaf shape. We also demonstrate that shade-induced changes in leaf primordium gene expression largely do not overlap with those found in successively initiated leaf primordia, providing evidence against classic hypotheses that shaded leaf morphology results from the prolonged production of juvenile leaf types.Not only is the shape of a single leaf highly multivariate, but the shape of leaves within and between plants is influenced by evolutionary, genetic, developmental, and environmental factors (Chitwood et al., 2012a, 2012b, 2013, 2014; Chitwood and Topp, 2015). Over a lifetime, a plant will produce numerous leaf shapes, influenced by the development of individual leaves as their blades unequally expand (allometric expansion; Hales, 1727; Remmler and Rolland-Lagan, 2012; Rolland-Lagan et al., 2014) and the different types of leaf shapes a plant produces at successive nodes, a result of the temporal development of the shoot apical meristem (SAM; heteroblasty; Goebel, 1900; Ashby, 1948; Poethig, 1990, 2010; Kerstetter and Poethig, 1998). Therefore, leaf shape in a single plant cannot be reduced to a single shape, as shapes are ephemeral, changing from one moment to the next in individual leaves, and the shapes of leaves emerging from successive nodes are not necessarily constant.When environmental conditions induce changes in leaf shape (plasticity), it is within the above-mentioned developmental context that morphology must be considered (Diggle, 2002). For example, a once prevailing hypothesis was that changes in leaf shape across successive nodes were dependent on nutrition. The rationale for this premise rested on the unique (often irregular) shapes of first emerging leaves, thought to result from abortive development because of reduced photosynthetic support from any previous leaves. Similarly, many plants produce juvenile-looking leaves when shaded, interpreted again as resulting from reduced photosynthate (Goebel, 1908; Allsopp, 1954). This hypothesis has recently been revisited, as sugar has been found to be a signal mediating vegetative phase change (Yang et al., 2013; Yu et al., 2013). Careful morphological studies of leaf development can separate the different effects of shade and heteroblasty, refuting these ideas, at least at a morphological level in some species. In Cucurbita spp., the changes in successively emerging leaves are morphologically observable in early leaf primordia. Despite light intensity-induced changes in the heteroblastic progression of mature leaf morphology, leaf primordia initiated under low light resemble those initiated in sun. This suggests that, in Cucurbita spp., light intensity-induced morphology results from plastic responses later in leaf development after initiation rather than through changes in heteroblasty and timing (Jones, 1995).In addition to the responses to decreased light intensity discussed above, plants can also sense changes in light quality. Phytochrome proteins, which sense decreases in the ratio of red light to far-red light (R:FR), initiate the shade-avoidance response upon detecting deflected light from competitors (Smith and Whitelam, 1997). Shade-avoiding plants typically exhibit increases in internode and petiole length, reduced leaf mass per area, alterations in stomatal patterning, and shoot/root resource reallocation as an adaptive response to overgrow competitors and better intercept light (Casal, 2012). The changes in leaf shape in response to shade are more ambiguous and can be radically different based on morphological context (such as simple versus complex leaves) and species. For example, in Arabidopsis (Arabidopsis thaliana), shade avoidance is typified by greater increases in petiole length relative to the blade region and inhibited blade outgrowth (Tsukaya et al., 2002; Kim et al., 2005; Kozuka et al., 2005), but in wild relatives of domesticated tomato (Solanum lycopersicum), both the petiole and rachis region expand equally and blade outgrowth is increased. These shade-avoiding responses inversely correlate with the amount of vegetation present in the native locale of an accession, implying adaptive significance in tomato (Chitwood et al., 2012a).Here, we begin by characterizing the effects of simulated foliar shade on leaf morphology in domesticated tomato and its wild relatives through a meta-analysis of more than 18,000 previously published leaflets (Chitwood et al., 2012a, 2012b, 2014). We find that the effects of decreased R:FR on leaf shape are strong, but only when multiple morphometric parameters are considered across leaflets, both within leaves and across the leaf series, of individual plants. Circularity (a measure of leaflet serration in tomato) and leaf complexity are the most strongly affected individual traits during the shade-avoidance response. We then seek to determine when different shade-avoiding traits manifest during leaf development by swapping plants between light treatments during early leaf development. Leaves will plastically increase their blade area late into development if moved into simulated foliar shade from an initial sunlight treatment, but other traits, such as stomatal patterning, are irrevocably specified earlier during development. Observing increases in SAM size under low R:FR conditions, we then perform laser-capture microdissection to analyze the effects of simulated foliar shade on gene expression in the first emerging leaf primordium (P1) and the meristem. The most conspicuous change in gene expression is increased expression of LeT6 (the tomato ortholog of SHOOTMERISTEMLESS) and other indeterminacy-related genes in the P1, consistent with the increases in leaflet serration and leaf complexity observed in tomato during the shade-avoidance response. Finally, to determine the developmental context of our observations, we compare gene expression changes during shade avoidance with heteroblastic gene expression (i.e. successively initiating leaves at the same developmental stage) in the SAM and young leaf primordia. Gene expression induced by decreased R:FR in light and that which changes with progression through the heteroblastic series in leaf primordia are largely distinct, suggesting not only that the shade-avoidance response is not mediated through heteroblastic changes but also that increases in leaf complexity in these two contexts employ distinct suites of genes.     

Sex Chromosome Translocations in the Evolution of Reproductive Isolation

Haldane's rule states that in organisms with differentiated sex chromosomes, hybrid sterility or inviability is generally expressed more frequently in the heterogametic sex. This observation has been variously explained as due to either genic or chromosomal imbalance. The fixation probabilities and mean times to fixation of sex-chromosome translocations of the type necessary to explain Haldane's rule on the basis of chromosomal imbalance have been estimated in small populations of Drosophila melanogaster. The fixation probability of an X chromosome carrying the long arm of the Y(X·Y^L) is approximately 30% greater than expected under the assumption of no selection. No fitness differences associated with the attached Y^L segment were detected. The fixation probability of a deficient Y chromosome is 300% greater than expected when the X chromosome contains the deleted portion of the Y. It is suggested that sex-chromosome translocations may play a role in the establishment of reproductive isolation.     

Characterization of Hormonal Complex in Pea Phenotypes Differing in Leaf Morphology

Two genotypes of the pea (Pisum sativum L.) with wild-type leaves (variety Orlovchanin, Af/Af genotype) and the afila morphotype (aphyllous variety Nord, af/af genotype) were compared in terms of growth performance and hormonal characteristics of different leaf parts and the whole plant. The replacement of leaflets by tendrils in the afila variety led to a reduction in total dry weight and the area of photosynthesizing surfaces. The loss of leaflets was partly compensated for by rapid expansion of stipules at early stages of plant development and by the hypertrophy of tendrils at later stages. The excessive development of stipules in afila plants was paralleled by the increase in IAA and cytokinin level in their tissues. The hypertrophied development of tendrils and chlorophyll accumulation in tendrils of afila plants was correlated with a high IAA and cytokinin content at a low ABA background level. The elevated content of ABA in tissues of wild-type plants was associated with the preferential development of leaflets and a larger transpiratory surface compared with those in the afila form. It is assumed that this feature ensures the turgescence of wild-type plants. The possible involvement of phytohormones in growth and morphogenesis of pea mutants is discussed.     

Genetic Control of Leaf Morphology: A Partial View

The partial-shoot theory of the leaf was a controversial hypothesisrevived by Arber and supported by her morphological and anatomicalstudies. This theory highlighted the parallels between leavesand shoots and contrasted with an alternative view that leaves,with their limited growth potential, are completely distinctfrom shoots. Pea morphological mutants with altered growth potentialin their compound leaves are described. The unifoliata mutanthas a limited growth potential relative to wild-type;cochleata,afila and insecatus have extended potentials. Characterizationof theunifoliata mutation and gene expression patterns indicatethat unifoliata is a common factor in pea compound leaf andfloral shoot development, and so provides rudimentary supportfor the idea that some leaves have shoot-like characteristics.Tomato leaves are also considered to lend tentative support.The afila and insecatus leaf forms are described as bipinnateand weakly bipinnate, respectively. These and the tendril-lessmutant are potential phenocopies of legume relatives, an ideabased on Vavilov's law of homologous series of variation. Arberillustrated, but did not articulate in genetical terms, thatmorphological variation in structures within an individual plantcan be interpreted as reiteration of design. Analogous withVavilov's view, this can be considered a consequence of thesame genetic programme in a different location.Copyright 2001Annals of Botany Company Agnes Arber, compound leaf, genetics, knotted1, legume, morphology, mutant, partial-shoot, pea, Pisum sativum, unifoliata, Vavilov     

Artichoke Leaf Morphology and Surface Features in Different Micropropagation Stages

Artichoke (Cynara scolymus L.) leaf size and shape, glandular and covering trichomes, stomatal density, stomata shape, pore area and epicuticular waxes during micropropagation stages were studied by scanning electron microscopy (SEM) and morphometric analysis with the aim to improve the survival rate after transfer to greenhouse conditions. Leaves from in vitro shoots at the proliferation stage showed a spatular shape, ring-shaped stomata, a large number of glandular trichomes and juvenile covering hairs, but failed to show any epicuticular waxes. Leaves from in vitro plants at the root elongation stage showed a lanceolated elliptic shape with a serrated border, elliptical stomata, decreased pore area percentage, stomatal density, and mature covering trichomes. One week after transfer to ex vitro conditions, epicuticular waxes appeared on the leaf surface and stomata and pore area were smaller as compared to in vitro plants. Artichoke acclimatization may be improved by hormonal stimulation of root development, since useful morphological changes on leaves occurred during root elongation.     

Richard Owen, Morphology and Evolution

Richard Owen has been condemned by Darwinians as an anti-evolutionist and an essentialist. In recent years he has been the object of a revisionist analysis intended to uncover evolutionary elements in his scientific enterprise. In this paper I will examine Owen's evolutionary hypothesis and its connections with von Baer's idea of divergent development. To give appropriate importance to Owen's evolutionism is the first condition to develop an up-to-date understanding of his scientific enterprise, that is to disentagle Owen's contribution to the modernization of typology and morphology. I will argue that Owen's Platonic essentialism is rhetorical and incongruous. On the contrary, an interpretation of the archetype based on Aristotle's biological works makes possible a new conception of type, based on a homeostatic mechanism of stability. The renewal of morphology hinges on homological correspondences and a homeostatic process is also the origin of serial and special homology. I will argue that special homology shows an evolutionary orientation insofar as it is a typically inter-specific character while serial homology is determined through an elementary usage of the categories of developmental morphology. This revised version was published online in July 2006 with corrections to the Cover Date.     

山茶属的叶表皮形态及其分类学意义

在光学显微镜下观察了山茶属（Camellia)19个组36个代表种的叶表皮形态,发现上述植物的叶上下表皮细胞表面观形状均为不规则形,气孔器仅在下表皮存在,且一致为环列型;对上述植物中18个组30个种的叶下表皮进行扫描电镜观察,其特片为：气孔形状为梭形或长卵形,气孔外拱盖内缘光滑或呈浅波状,波状,气孔器附近的角质膜平坦或皱褶,表面光滑或有多种纹饰,这些特征可作为区分种或变种的依据,但与植物的外部形态等特征没有相关性。     

中国剪股颖属部分种叶下表皮微形态的研究

用光学显微镜对中国剪股颖属植物14种及1变种叶下表皮微形态特征进行了研究.结果显示:(1)剪股颖属植物叶下表皮长细胞多为长筒形,副卫细胞为平行形,脉上常见刺细胞,脉间有刺细胞或无或偶见,脉间具有短细胞或缺如;脉上硅细胞大多为结节形.(2)种间叶表皮的差异主要表现在脉间长细胞的形状及细胞壁的平直与否,气孔器分布的列数,脉间短细胞的有无,脉间刺细胞的有无,表明叶下表皮的差异可以作为种间的分类依据.(3)叶下表皮微形态的证据不支持山东剪股颖(Agrostis shandongensis F.Z.Li)作为玉山剪股颖(A.infirma Büse.)的异名处理,支持山东剪股颖和昆嵛山剪股颖(A.transmorrisonensis Hayata var.kunyushanensis F.Z.Li)的成立.并对昆嵛山剪股颖重新命名为[A.sozanensis Hayata var.kunyushanensis(F.Z.Li)F.Z.Li & C.M.Xu].     

Increased Reproductive Allocation of Rumex japonicus Caused by Leaf Clipping

Abstract To elucidate the effects of herbivory by chrysomelid beetles on Rumex japonicus, rosette leaves were clipped and the subsequent fruit production and root growth were observed. The increase of leaf biomass of some clipped plants was greater than that of control plants, although this varied among individual plants. The root growth of clipped plants was less than that of control plants. Fruit production increased with plant size, and there was no difference in fruit production between clipped and control plants. Reproductive allocation (fruit biomass, relative to fruit biomass plus root growth) increased with plant size; it was greater in clipped plants than in control ones. Based on these results, reproductive allocation strategy against herbivory was discussed.     

Mutants in Arabidopsis thaliana Altered in Epicuticular Wax and Leaf Morphology

We report eight new mutants in Arabidopsis thaliana possessing altered leaf morphology and epicuticular wax. These were isolated from a T-DNA-mutagenized population using a visual screen for altered leaf reflectance, i.e. increased glaucousness or glossiness. The mutants were placed into three distinct classes based on alterations in overall plant morphology: knobhead (knb), bicentifolia (bcf), and wax. The four knb mutants formed callus-like growths in the axillary region of the rosette leaves and apical meristem, the two bcf mutants produced hundreds of narrow leaves, and the two wax mutants had leaves and stems that were more glossy than wild type and organs that fused during early development. Leaves of knb and bcf were more glaucous and abnormally shaped than wild type. Epicuticular wax crystals over knb and bcf leaf surfaces (where none were present on wild type) likely contributed to their more glaucous appearance. In contrast, the glossy appearance of the wax mutants was associated with a reduced epicuticular wax load on both leaves and stems. One representative from each phenotypic class was selected for detailed analyses of epicuticular wax chemistry. All three lines, knb1, bcf1, and wax1, had dramatic alterations in the total amounts and relative proportions of their leaf epicuticular wax constituents.