关于一些植物学术语的中译等问题(三)

(1)确定rhizome的中文译名"根状茎"符合此术语的定义,同时认为另一中文译名"根茎"不符合有关定义,且易引起误解,应予废弃。(2)介绍了在中国植物学文献中稀见的2种属于有限花序类的花序类型,有限伞形花序和有限头状花序。根据有关欧美专家的花序研究,介绍了在中国植物学文献中放在无限花序类的隐头花序和柔荑花序系由聚伞花序演化而出,而应属于有限花序类的论断;同时,作者提出楼梯草属梨序楼梯草组的雄隐头花序系由同属的骤尖楼梯草组的有限头状花序演化而出的论点。     

一些花序的新定义和一个新的花序分类系统——植物学教材质疑(六)

花序是生花的分枝结构或系统,通常是被子植物科的重要特征,与传粉密切相关。花序教学的困难可能来自各教材在花序定义和分类上存在的问题。本文重新定义了一些花序类型,如有限和无限花序、伞房花序、轮伞花序,也澄清了伞形花序、柔荑花序、头状花序和隐头花序等花序分类上的一些混乱。笔者提议将花簇生和因花序退化而形成的单花列为花序类型。最后,本文提出了一个新的花序分类系统,增加了一些分类单元。     

楼梯草属研究随记

在该文中首次给出革叶楼梯草的雄头状花序描述; 还给出樱叶楼梯草雄头状花序的修正描述和兜苞墨脱楼梯草的修正特征集要; 写出托叶楼梯草和南川楼梯草二种的分类学修订,其中包括2新变种和2新等级; 描述了小叶楼梯草组的1新种和骤尖楼梯草组的3新种; 数年前被归并为异名的兜苞墨脱楼梯草和五肋楼梯草得到恢复。     

楼梯草属研究随记

在该文中首次给出革叶楼梯草的雄头状花序描述;还给出樱叶楼梯草雄头状花序的修正描述和兜苞墨脱楼梯草的修正特征集要;写出托叶楼梯草和南川楼梯草二种的分类学修订,其中包括2新变种和2新等级;描述了小叶楼梯草组的1新种和骤尖楼梯草组的3新种;数年前被归并为异名的兜苞墨脱楼梯草和五肋楼梯草得到恢复。     

南溪楼梯草,云南荨麻科一新种

该文描述了自云南东南部发现的荨麻科楼梯草属一新种,南溪楼梯草(Elatostema nanxiense)。此新种与田林楼梯草(E. tianlinense)相似,但其叶具三出脉,边缘具浅圆齿或小钝齿,雄总苞苞片较少,8枚,排成一层,背面有1～3条纵肋,只1枚在顶端具角状突起而与后者相区别。此外,此新种与盘托楼梯草系的广布种盘托楼梯草(E. dissectum)的区别在于其茎被糙伏毛,叶呈椭圆形,具三出脉,雄头状花序的花序梗较短,雄总苞苞片较少,呈宽卵形或横长方形,背面有1～3条纵肋,雄小苞片有缘毛。     

广西楼梯草属三新种和一新变种

描述了在中国广西发现的楼梯草属3新种和1新变种:马山楼梯草Elatostema mashanense W.T.Wang & Y.G.Wei与滇黔楼梯草E.backeri H.Schroter相近缘,但茎被向上展的短糙伏毛,叶顶端通常尾状渐尖,边缘具小牙齿或圆齿,具三出脉而与后者相区别。变种毛茎圆序楼梯草Elatostema gyrocephalum W.T.Wang&Y.G.Weivar.pubicaule W.T.Wang&Y.G.Wei的茎在近顶端处密被短柔毛,雌花序托不分裂,苞片中部黑色而与模式变种不同。黑苞楼梯草Elatostema nigribracteatum W.T.Wang&Y.G.Wei与显苞楼梯草E.bracteosum W.T.Wang在亲缘关系上相近,但茎被微柔毛,叶有短柄,叶片较小,长达7mm,纸质,上面无毛,钟乳体较小,长0.1～0.15mm,雌花序分裂成2个二回头状花序,苞片和小苞片呈黑色,无毛,花序托上有数条小枝,而与后者明显区分。天峨楼梯草Elatostema tianeense W.T.Wang&Y.G.Wei似E.hookeriano Wedd,但叶在边缘下部三分之一以上或中部以上有较多小牙齿,具半离基三出脉,托叶较小,狭三角形或三角状钻形,长1～2.5mm,雌花枝粗壮,雌苞片条状三角形,无角状突起而不同。     

云南楼梯草属二新种

该文描述了自云南东南部发现的荨麻科楼梯草属2新种。其中,文山楼梯草与上林楼梯草在亲缘关系上相近,与后者的区别在于本种的茎密被短柔毛,叶片在基部斜楔形,具半离基三出脉,雌头状花序的花序托较小,长约1.2 mm,宽1 mm,不分裂,其雌苞片约12,不等大,只3枚在顶端具角状突起。第二种,绿突楼梯草与马关楼梯草近缘,与后者的区别在于茎密被反曲的柔毛和贴伏的短柔毛,雄花序较长,雄总苞的苞片6枚,排成2层,2外层苞片较大,背面具1绿色纵列龙骨状突起和4或6绿纵肋,4内层苞片较小,背面近中央有1绿色角状突起。     

云南楼梯草属二新种

该文描述了自云南东南部发现的荨麻科楼梯草属二新种。(1)文山楼梯草,与上林楼梯草在亲缘关系上相近,与后者的区别在于本种的茎密被短柔毛,叶片在基部斜楔形,具半离基三出脉,雌头状花序的花序托较小,长约1.2 mm,宽1 mm,不分裂,其雌苞片约12,不等大,只3枚在顶端具角状突起。(2)绿突楼梯草,与马关楼梯草近缘,与后者的区别在于茎密被反曲的柔毛和贴伏的短柔毛,雄花序较长,雄总苞的苞片6枚,排成2层,2外层苞片较大,背面具1绿色纵列龙骨状突起和4或6绿纵肋,4内层苞片较小,背面近中央有1绿色角状突起。     

被子植物花序的演化趋势(上)

被子植物最原始的花序类型,认为是具叶的聚伞花序。在木兰科 Magnoliaceae,Winteraceae,香荔枝科 Annonac-eae,五桠果科 Dilleniaceae,毛莨科 Ranunculaceae,罂粟科 Papaveraceae 和 (?)薇科 Rosaceae 等一些较原始科中例子可以说明,甚至它们的单生花也属一种衍生状况。从毛茛科 Ranuncula(?),罂粟科,蔷薇科,虎耳草科 Saxifragac-eae,夹竹桃科 Apocynaceae,桔梗科 Campanulales 和(?)科 Violaceae 的实例证明,有限花序比无限花序愿始。从实例中可看到花序减化和扩大的两种趋势。在菊科和禾本科中,两种完全不同的发展形式和互交错发生,形成复合花序的复杂类型。花序的个体发育,与枝顶端从营养状态特有的组织学和生理学性质,转变到生殖校顶端有的不同性质有关。如果这种转变与花附属器官原基的分化同时发生或紧跟在其后发生,那就形成一朵单花,或一个简单的具叶的聚(?)花序。在具有非常复杂花序的植物中,如菊科的头状花序和禾本科的圆锥花序,是在各花原基分化之前转变的。此外,形成复杂花序(包括与营养叶强烈地分化的苞片)的生殖顶端,比形成较简单、分化程度较小的花序的营养顶端,其分化更为强烈。与营养枝有关的花序特点,在很大程度上,取决于枝顶端从营养状态到生殖状态转变的缓急度。花序的形状与生殖顶端原基中有丝分裂的方向有关。无限花序起源于有限花序,常分两步进行,即减化继之以扩大。这些步骤受交替选择的支配:第一,由于对较短的生长期的反应,生殖周期就缩短;第二,由于对选择更适宜环境的反应,使种子的产量增加。当生殖周期较长时,能伸长的总状花序就富有适应性,不过生长条件不是最好的,如低光照,缺少矿物质或其他限制。具重复合(?)分枝的花序,对于外界环境的反应,有高度的灵活性,故能很好地适应于那些逐年生长季节波动很大的区域。花序的演化很好地说明了演化趋势的两个普遍特性,即结构的保守性以及沿最小阻力线发生的适应(?)变。     

楼梯草属苞片形态和演化趋势

(Ⅰ)对荨麻科楼梯草属的苞片和小苞片的形态进行了全面研究。(Ⅱ)该属原始群疏伞楼梯草组的雄聚伞花序苞片在每花序为15-90枚,纸质,绿色,狭卵形、狭三角形或条形,长0.5-4mm,扁平,无任何突起,而与楼梯草族的冷水花属和赤车属的聚伞花序苞片极为相似,因此,上述各种形态可以视为楼梯草属苞片的原始特征,并据此观察到总苞苞片的以下演化趋势:(1)近等大,形状相似,在花序托边缘轮生形成一层→排列为二层,外层2苞片对生,较大,内层苞片较小,形状稍不同;(2)狭卵形,狭三角形或条形→宽卵形或宽三角形,或扁半圆形→由于长度强烈缩小,宽度增大而最终消失;(3)扁平→顶端兜形→船形→船形,顶端突起成细筒;(4)无任何突起0背面有1龙骨状突起,或有1-6条纵肋或狭翅1顶端具短到长的角状突起→背面顶端之下具角状突起;(5)分生→基部合生→由于长度强烈缩小,宽度强烈增大,总苞苞片合生成一横条形狭片;(6)在数目上,由每花序的7-45枚,一方面增加到50-180枚,另一方面则减少到5枚以下。同时,观察到小苞片形态以下演化趋势:(1)膜质,半透明,白色0具褐色线纹或呈褐色→呈黑色1薄膜质,透明,无色;(2)扁平→顶端兜形→船形;(3)无任何突起→顶端或在背面顶端之下具角状突起;(4)在数目上,由每花序的7-45枚一方面增加到100或数百枚,甚至达1千到数千枚,另一方面则减少到5枚以下,甚至到0枚。上述演化趋势有助于了解属下各级分类群的演化水平。     

The geographic, taxonomic and temporal distribution of determinate growth in marine gastropods

Many marine gastropods are characterized by determinate growth, as inferred from the presence of unique terminal elaborations of the shell's aperture. Although determinate growth has evolved repeatedly in most major gastropod clades, it is especially frequent among siphonate caenogastropods. Analyses of shallow-water assemblages show that the incidence of species with determinate growth is far higher in the tropics (especially the tropical Pacific and Indian Oceans) than at higher latitudes. Compilations of fossil assemblages from warm-water environments indicate that, although determinate growth occurred in some Palaeozoic gastropods, it became widespread only in the Neogene. In some groups, terminal apertural elaborations arose in lineages whose growth was more or less continuous and indeterminate, but in others it was derived either from or was ancestral to episodic growth. The hypothesis that periodic or terminal apertural elaborations evolved as a means to dispose of calcium carbonate once growth in the spiral direction ceased is rejected in favour of functional interpretations. Among the latter, the roles of modified apertures in defence and in mate recognition are explored, but no firm conclusion regarding the latter possibility can be drawn owing to our ignorance of mate recognition in gastropods.     

The response of an autumn-sown determinate faba bean to different plant distributions

The response of an autumn-sown determinate selection, 858 , to different plant distribution patterns was examined in field trials during the two seasons 1985/86 and 1986/87 at the University of Nottingham. Plants were sown at two densities (20 and 40 plants per m2) and at three different row widths (11.9, 23.8 and 47.6 cm) in the autumn of each season. Plant numbers and combined yields were greater in 1986/87 than in 1985/86. Grain yield was unaffected by differences in inter-row spacing and this was ascribed to the early attainment of complete ground cover even when plants were grown in widely spaced rows. Yield was most strongly correlated with seed numbers per m². An examination of yield on a per plant basis suggested that narrow inter-row spacings were more productive at low plant densities, while yield per plant was greater at higher densities if the crop was grown on wider inter-row spacings. It was concluded that autumn-sown determinate forms of faba bean were able to compensate for large changes in plant distribution and consequently yield was unaffected.     

黄瓜复雌花等6对基因间连锁遗传关系的研究

为探索黄瓜复雌花基因mp、有限生长基因de、叶片皱缩基因cr、叶片无毛基 因gl-2、果皮多刺基因ns和果实有棱基因Tu间的独立或连锁遗传关系,试验选用了带上述6对基因的黄瓜纯合亲本NCG128、NCG 157、WI 275 7和NCG 042,以这些亲本配制4个杂交组合,获得F1,F2,BC1a和BC1b代群体,采用孟得尔遗传公式和计算机程序分析参试性状在各杂交后代中的基因型分离情况。结果表明:基因mp和de,cr和gl-2,cr和Tu,Tu和gl-2,Tu和ns间存在连锁遗传关系,它们的基因间距离分别为0.21,0.12,0.38,0.24,0.32cM(厘摩)。 Abstract:To study the linkage inheritance among gene mp for multi-pistillate flowering,de for determinate growth type,cr for crinkled leaf,gl-2 for glabrous leaf,ns for numerous spine,and Tu for tuberculate fruit in cucumber,the inbred NCG128,NCG157,WI2757 and NCG 042 were used as parents for 4 coombinations in the experiment.The traits of these genes were measured in field and the data was analyzed with a computer program SASGENE.The result indicated that the gene mp and de,cr and gl-2,cr and Tu,Tu and gl-2,Tu and ns had linkage relationship,and the distance between them was 0.21,0.12,0.38,0.24,0.32cM,respectively.     

The development and structure of root nodules on bambara groundnut [Voandzeia (Vigna)subterranea]

The infection of Vigna subterranea (formerly Voandzeia subterranea) by Bradyrhizobium strain MAO 113 (isolated from V. subterranea) was examined by light and transmission electron microscopy. Bacteria accumulated on the epidermis close to root hairs, and subsequently entered the latter via infection threads. Most of the steps involved in nodule formation were generally characteristic of determinate nodules, such as those which form on the closely related V. radiata. For example, nodule meristems were induced beneath the root epidermis adjacent to infected root hairs, but prior to infection of the meristem by rhizobia. Moreover, after the infection of some of the meristematic cells by the infection threads, and the release of the rhizobia into membrane-bound vesicles, the infection process ceased and dissemination of the rhizobia was by division of already-infected host cells. However, there were some aspects of this process in V. subterranea which have been more commonly described in indeterminate nodules. These include long infection threads entering a number of cells within the meristems simultaneously and a matrix within infection threads which was strongly labelled with immunogold monoclonal antibodies, MAC236 and MAC265, which recognize epitopes on an intercellular glycoprotein. The MAC236 and MAC265 antibodies also recognized material in the unwalled infection droplets surrounding bacteria which were newly-released from the infection threads. The amount of labelling shown was more characteristic of the long infection threads seen in indeterminate nodules such as pea (Pisum sativum) and Neptunia plena. The structure of mature V. subterranea nodules was similar to that described for other determinate nodules such as Glycine max, Vigna unguiculata and V.radiata, i.e. they were spherical and the infected zone consisted of both infected and uninfected cells. Surrounding the infected tissue was an inner cortex of uninfected cell layers containing the putative components of an oxygen diffusion barrier (including glycoprotein-occluded intercellular spaces), and an outer cortex with cells containing calcium oxalate crystals.     

Do reef corals age?

Hydra is emerging as a model organism for studies of ageing in early metazoan animals, but reef corals offer an equally ancient evolutionary perspective as well as several advantages, not least being the hard exoskeleton which provides a rich fossil record as well as a record of growth and means of ageing of individual coral polyps. Reef corals are also widely regarded as potentially immortal at the level of the asexual lineage and are assumed not to undergo an intrinsic ageing process. However, putative molecular indicators of ageing have recently been detected in reef corals. While many of the large massive coral species attain considerable ages (>600 years) there are other much shorter‐lived species where older members of some populations show catastrophic mortality, compared to juveniles, under environmental stress. Other studies suggestive of ageing include those demonstrating decreased reproduction, increased susceptibility to oxidative stress and disease, reduced regeneration potential and declining growth rate in mature colonies. This review aims to promote interest and research in reef coral ageing, both as a useful model for the early evolution of ageing and as a factor in studies of ecological impacts on reef systems in light of the enhanced effects of environmental stress on ageing in other organisms.     

Twelve fundamental life histories evolving through allocation‐dependent fecundity and survival

An organism's life history is closely interlinked with its allocation of energy between growth and reproduction at different life stages. Theoretical models have established that diminishing returns from reproductive investment promote strategies with simultaneous investment into growth and reproduction (indeterminate growth) over strategies with distinct phases of growth and reproduction (determinate growth). We extend this traditional, binary classification by showing that allocation‐dependent fecundity and mortality rates allow for a large diversity of optimal allocation schedules. By analyzing a model of organisms that allocate energy between growth and reproduction, we find twelve types of optimal allocation schedules, differing qualitatively in how reproductive allocation increases with body mass. These twelve optimal allocation schedules include types with different combinations of continuous and discontinuous increase in reproduction allocation, in which phases of continuous increase can be decelerating or accelerating. We furthermore investigate how this variation influences growth curves and the expected maximum life span and body size. Our study thus reveals new links between eco‐physiological constraints and life‐history evolution and underscores how allocation‐dependent fitness components may underlie biological diversity.     

Determinate growth is predominant and likely ancestral in squamate reptiles

Body growth is typically thought to be indeterminate in ectothermic vertebrates. Indeed, until recently, this growth pattern was considered to be ubiquitous in ectotherms. Our recent observations of a complete growth plate cartilage (GPC) resorption, a reliable indicator of arrested skeletal growth, in many species of lizards clearly reject the ubiquity of indeterminate growth in reptiles and raise the question about the ancestral state of the growth pattern. Using X-ray micro-computed tomography (µCT), here we examined GPCs of long bones in three basally branching clades of squamate reptiles, namely in Gekkota, Scincoidea and Lacertoidea. A complete loss of GPC, indicating skeletal growth arrest, was the predominant finding. Using a dataset of 164 species representing all major clades of lizards and the tuataras, we traced the evolution of determinate growth on the phylogenetic tree of Lepidosauria. The reconstruction of character states suggests that determinate growth is ancestral for the squamate reptiles (Squamata) and remains common in the majority of lizard lineages, while extended (potentially indeterminate) adult growth evolved several times within squamates. Although traditionally associated with endotherms, determinate growth is coupled with ectothermy in this lineage. These findings combined with existing literature suggest that determinate growth predominates in both extant and extinct amniotes.     

Restructuring plant types for developing tailor-made crops

Plants have adapted to different environmental niches by fine-tuning the developmental factors working together to regulate traits. Variations in the developmental factors result in a wide range of quantitative variations in these traits that helped plants survive better. The major developmental pathways affecting plant architecture are also under the control of such pathways. Most notable are the CLAVATA-WUSCHEL pathway regulating shoot apical meristem fate, GID1-DELLA module influencing plant height and tillering, LAZY1-TAC1 module controlling branch/tiller angle and the TFL1-FT determining the floral fate in plants. Allelic variants of these key regulators selected during domestication shaped the crops the way we know them today. There is immense yield potential in the ‘ideal plant architecture’ of a crop. With the available genome-editing techniques, possibilities are not restricted to naturally occurring variations. Using a transient reprogramming system, one can screen the effect of several developmental gene expressions in novel ecosystems to identify the best targets. We can use the plant's fine-tuning mechanism for customizing crops to specific environments. The process of crop domestication can be accelerated with a proper understanding of these developmental pathways. It is time to step forward towards the next-generation molecular breeding for restructuring plant types in crops ensuring yield stability.