水车前属一新种及其核型

一、形态学特征出水水菜花新种图1 Ottelia emersa Z.C.Zhao et R.J.Luo sp.nov.     

中国海菜花属植物的性状分析

本文对中国海菜花属全部已知分类群的84个形态学、生物学和生态学性状,进行了R分析和主成分分析。R分析结果表明,被研究的性状可明显地划分为若干组高度相关的性状,它们或表明本属向次生性陆生和异花传粉方向演化,或具重要的分类价值。主成分分析结果表明,仅前16个主成分几乎可保留84个性状的全部信息量,这说明在中国海菜花属分类研究中所选性状很合理;前3个主成分可保留总信息量的76.56%,说明在三维空间内能较好地反映中国海菜花属所有已知分类群间的相对位置。     

海菜花属的分支学研究

本文选取了与海菜花属系统发育有重要关系的19个性状,采用分支分析方法,研究了代表中国海菜花属全部已知分类群的18个居群的系统发育关系;根据简约性原则,构建了18个居群的分支图。结果表明,18个居群可划分为4类,它们分别对应于现知的4个分类学种,而与数值分类学研究中的Q分析结果基本一致;在分类群的划分上,分支分析与Q分析一样有效,并能反映系统发育关系。本文最后对海菜花属的起源和演化作了探索性推测,认为本属可能最迟在白垩纪末起源于冈瓦纳古陆的热带湖沼地区,此后分化成沉水叶多花支、沉水叶单花支和浮水叶单花支繁衍演化。     

SYMMETRY AND DEVELOPMENT OF LIMNOBIUM SPONGIA (HYDROCHARITACEAE)

Limnobium spongia produces upright vegetative axes and prostrate stolons. The upright axes bear new stolons, whereas the stolons bear new upright axes and fertile and sterile branching systems. Upright axes and fertile and sterile branching systems are all interpreted to have sympodial growth. However, it was not determined whether growth of stolons is monopodial or sympodial. Both stolons and upright axes branch in alternate plastochrons, and branching is achieved solely by the bifurcation of apical meristems. Each meristematic bifurcation is interpreted to represent the formation of a precocious lateral bud. The upright axes develop from presumed precocious lateral buds on stolons, whereas such buds on upright axes produce renewal shoots. Limnobium spongia exhibits a marked degree of mirror-image symmetry.     

SOME ABNORMAL FLOWERS OF ARGEMONE MEXICANA AND THEIR BEARING ON THE MORPHOLOGY OF THE GYNOECIUM OF PAPAVERACEAE

Abnormal flowers of Argemone mexicana are described in whichthe gynoecium has been transformed into a cup with lobed marginor into free leafy carpels. The number of lobes or leafy carpelsin such gynoecia is found to vary from three to five. This agreeswith the general view of systematists regarding the number ofcarpels composing the gynoecium in this species, and is againstthe views of Saunders and Dickson who postulate twice as manycarpels.     

SYMMETRY AND DEVELOPMENT OF PISTILLATE VALLISNERIA AMERICANA (HYDROCHARITACEAE)

Pistillate Vallisneria americana produces upright vegetative axes and prostrate stolons and develops in a manner fundamentally similar to that of Limnobium spongia (Hydrocharitaceae) and certain other taxa of Alismatidae. The cauline portions of pistillate V. americana branch solely by the bifurcation of apical meristems, and their mode of branching offers clues concerning the nature of the plant body. The upright axes are interpreted to have sympodial growth, whereas at least certain stolons appear to be entirely monopodial. The upright axes are either typical vegetative axes or turions; and of these, only turions appear to survive the winter in at least one locality. Pistillate V. americana produces intravaginal squamules (multi-seriate trichomes) although they appear reduced in number relative to those in certain other hydrocharitaceous and alismatid taxa. Vallisneria americana exhibits a notable degree of mirror image symmetry which differs somewhat from that of Limnobium spongia.     

FLORAL DEVELOPMENT OF HYDROCHARIS MORSUS-RANAE (HYDROCHARITACEAE)

In both male and female flowers of H. morsus-ranae the primordia of the floral appendages appear in an acropetal succession consisting of alternating trimerous whorls. In the male flower a whorl of sepals is followed by a whorl of petals, three whorls of stamens, and a whorl of filamentous staminodes. The mature androecial arrangement therefore consists of two antisepalous stamen whorls, an antipetalous whorl of stamens, and antipetalous staminodes. Shortly before anthesis, basal meristematic upgrowth between filaments of adjacent whorls produces paired stamens, joining Whorls 1 and 3, and Whorl 2 with the staminodial whorl. A central domelike structure develops between the closely appressed filaments of the inner stamen and staminodial whorl, giving the structure a lobed appearance. After petal inception in the female flower a whorl of antisepalous staminodes develop, each of which may bifurcate to form a pair of staminodes. During staminode development a girdling primordium arises by upgrowth at the periphery of the floral apex. The girdling primordium rapidly forms six gynoecial primordia, which then go on to produce six free styles with bifid stigmas. Intercalary meristem activity, below the point of floral appendage attachment, leads to the production of a syncarpous inferior ovary with six parietal placentae. The styles and carpels remain open along their ventral sutures. During the final stages of female floral development, several hundred ovules develop along the carpel walls, and three nectaries develop dorsally and basally on the three antipetalous styles.     

DEVELOPMENT AND VASCULATURE OF THE FLOWERS OF LOPHOTOCARPUS CALYCINUS AND SAGITTARIA LATIFOLIA (ALISMACEAE)

The development of the bisexual flower of Lophotocarpus calycinus and of the unisexual flowers of Sagittaria latifolia has been observed. In all eases floral organs arise in acropetal succession. In L. calycinus, after initiation of the perianth, the first whorl of stamens to form consists of six stamens and is ordinarily followed by two alternating whorls of six stamens each. The very numerous carpels arc initiated spirally. In the male flower of S. latifolia the androecium develops in spiral order. A few rudimentary carpels appear near the floral apex after initiation of the stamens. There are no staminodia. The female flower has a similar developmental pattern to that of Lophotocarpus except that a prominent residual floral apex is left bare of carpels. The vascular system in all flowers is semiopen, with vascular bundles passing to the floral organs in a pattern unrelated to the relative positions of those organs. The androecia of these two taxa are similar to those of some Butomaceae and relationships based on ontogeny and morphology are suggested. The gynoecia are meristically less specialized but morphologically more specialized than the gynoecia of Butomaceae.     

湖北省泽泻科、水鳖科、眼子菜科及茨藻科植物花粉形态研究

本文利用光镜及扫描电镜对湖北省泽泻科、水鳖科、眼子菜科及茨藻科11属29种1变种1变型植物(另加采于湛江的软骨草)的花粉形态进行了研究,发现泽泻科植物花粉具多个圆形萌发孔,外壁表面为小刺状纹饰;茨藻科植物花粉具远极单槽,表面为绉波状纹饰;眼子菜科及本文研究的水鳖科植物花粉均无萌发孔,分别具网状和小刺状饰纹饰。1.茨藻科植物花粉最原始,泽泻科花粉较进化,眼子菜科花粉较水鳖科花粉进化;2.泽泻属与泽苔草属花粉较慈姑属花粉原始;3.鞘叶眼子菜亚屈花粉较眼子菜亚属的花粉处于更高演化阶段;4.多孔茨藻花粉在该科中最原始。本文工作尚对易变形水生植物花粉形态研究方法进行了尝试。     

INFLORESCENCE AND FLORAL DEVELOPMENT IN HOUTTUYNIA CORDATA (SAURURACEAE)

The inflorescence of Houttuynia cordata produces 45–70 sessile bracteate flowers in acropetal succession. The inflorescence apical meristem has a mantle-core configuration and produces “common” or uncommitted primordia, each of which bifurcates to form a floral apex above, a bract primordium below. This pattern of organogenesis is similar to that in another saururaceous plant, Saururus cernuus. Exceptions to this unusual development, however, occur in H. cordata at the beginning of inflorescence activity when four to eight petaloid bract primordia are initiated before the initiation of floral apices in their axils. “Common” primordia also are lacking toward the cessation of inflorescence apical activity in H. cordata when primordia become bracts which may precede the initiation of an axillary floral apex. Many of these last-formed bracts are sterile. The inflorescence terminates with maturation of the meristem as an apical residuum. No terminal flowers or terminal gynoecia were found, although subterminal gynoecia or flowers in subterminal position may overtop the actual apex and obscure it. Individual flowers have a tricarpellate syncarpous gynoecium and three stamens adnate to the carpels; petals and sepals are lacking. The order of succession of organs is: two lateral stamens, median stamen, two lateral carpels, median carpel. The three carpel primordia almost immediately are elevated as part of a gynoecial ring by zonal growth of the receptacle below the attachment of the carpels. The same growth elevates the stamen bases so that they appear adnate to the carpels. The trimerous condition in Houttuynia is the result of paired or solitary initiations rather than trimerous whorls. Symmetry is bilateral and zygomorphic rather than radial. No evidence of spiral arrangement in the flower was found.     

THE MORPHOLOGY, POSTEMBRYONIC DEVELOPMENT AND EVOLUTION OF STRIDULITRA IN REDUVIIDAE WITH SPECIAL REFERENCE TO THEIR TAXONOMIC IMPORTANCE (HETEROPTERA: REDUVIOIDEA)

Abstract  Data on stridulitral types, strial rumber, width, interspace and ontogenetic changes of stridulitral structures are provided and analyzed. Its significance on taxonomy is discussed.