Floral ontogeny in Scirpus, Eriophorum and Dulichium (Cyperaceae), with special reference to the perianth

BACKGROUND AND AIMS: Based on molecular phylogenetic analysis, it has been suggested recently that the Cyperaceae comprises only two subfamilies: the Mapanioideae and the Cyperoideae. In most flowers of the Cyperoideae, the whorl of inner stamens is reduced, resulting in tetracyclic flowers. In the more primitive (scirpoid) genera within the Cyperoideae, the perianth consists of two polysymmetric whorls, whereas the perianth parts in the more derived genera have been subject to modifications and/or reduction. Comparative studies of the many silky hairs of Eriophorum and of the eight bristles of Dulichium have given rise to much discussion about their homology. METHODS: The spikelet and floral ontogeny in freshly collected inflorescences was investigated using scanning electron microscopy. KEY RESULTS: Complete floral ontogenies are presented for Scirpus sylvaticus L., Eriophorum latifolium Hoppe and Dulichium arundinaceum (L.) Britton, with special reference to the perianth. The results in S. sylvaticus confirm the trimerous monocot-like organization of the flower. It is used as a model for floral development in Cyperoideae. In the early developmental stages, the androecium of E. latifolium is surrounded by a massive perigonial primordium, from which the many hair-like bristles originate. Consequently, the stamens develop among the hair primordia, more or less simultaneously. The hairs are arranged in whorls, which develop centripetally. The development of the perianth in D. arundinaceum starts with the formation of three initial perianth primordia opposite the stamens. Subsequently, two more abaxial bristle primordia, alternating with the stamens, originate simultaneously with the appearance of three adaxial bristle primordia in the zone where an adaxial inner perianth primordium is expected. CONCLUSIONS: The floral development in E. latifolium and D. arundinaceum can be considered as variations upon the scirpoid floral ontogenetic theme.     

The Genetics of Evolutionary Change in Senecio vulgaris L.: A QTL Mapping Approach

Abstract: The cosmopolitan weed Senecio vulgaris var. vulgaris is likely to have originated from the non-weedy S. vulgaris ssp. denticulatus from which it differs by showing no seed dormancy, by completing its life cycle from germination to seed formation much faster and by lacking ray florets. An F2 generation of 120 individuals obtained through selfing of one hybrid individual between var. vulgaris and ssp. denticulatus was used to construct a linkage map based on RAPD polymorphisms and the presence or absence of ray florets. This linkage map was used for a QTL analysis of 12 characters distinguishing the two taxa. For seven of these 12 characters, three significant QTLs could be found. One of these QTLs controls the speed of development, height of plants, leaf number, number of lateral branches and number of outer involucral bracts. A second QTL, located in the same linkage group, coincides with the ray floret locus and controls the number of disc florets. Plant height and leaf number are controlled by a third QTL in a different linkage group. Considering earlier evidence on the genetics of seed dormancy, it is argued that probably only three chromosomal regions, or even genetic loci, control seed dormancy, speed of development and presence or absence of ray florets as the ecologically most important differences between var. vulgaris and ssp. denticulatus. These findings have important implications for the genetics of evolutionary change and speciation.     

The effect of growth retardant application on floret site utilisation and assimilate distribution in ears of perennial ryegrass cv. S.24

Application of the growth retardant paclobutrazol (PP333), at 2 kg a.i. ha^-1 at spikelet initiation to plots of perennial ryegrass cv. S.24 in 1981 and 1982 significantly increased the number of seeds per spikelet present at final harvest by reducing the number of seeds aborted during seed development. Distribution of florets and seeds per spikelet was altered by PP333, as both basal and penultimate spikelets contained more florets and seeds than did those of untreated plants. Seed weight and germination were increased in florets of penultimate spikelets, although PP333 application delayed maturity by 3–5 days. In untreated plants, assimilate recovery was significantly lower from the terminal section of the ear, whereas in PP333 treated plants, no differences were found between basal, intermediate or terminal sections of the ear. PP333 increased assimilate demand at all sections of the ear when the ear and leaves were fed. The implications of this are discussed.     

Studies in African Cyperaceae 27. Miscellaneous new taxa and combinations

One new form of Fuirena Rottb., one new subspecies of Schoenoplectus Palla and one new variety of Carex L. are described from East Africa, viz. Fuirena leptostachya Oliv. f. nudiflora Lye, Schoenoplectus lateriflorus (Gmel.) Lye ssp. laevinux Lye and Carex bequaertii De Wild. var. maxima Lye. In addition, the following new combinations are made: Fuirena ciliaris (L.) Roxb. f. apetala (Wingfield) Lye, F. stricta Steudel ssp. chlorocarpa (Ridley) Lye, Schoenoplectus rhodesicus (Podlech) Lye, 5. corymbosus (Roem. & Schult.) J. Rayn. var. brachyceras (A. Rich.) Lye, S. confusus (N.E. Br.) Lye var. rogersii (N.E. Br.) Lye, S. erectus (Poiret) J. Rayn, ssp. raynalii (Schuyler) Lye, S. erectus (Poiret) J. Rayn. ssp. sinuatus (Schuyler) Lye, Eleocharis retroflexa (Poiret) Urban ssp. subtilissima (Nelmes) Lye, Machaerina Vahl subgen. Baumea (Gaud.) Lye, Machaerina flexuosa (Bock.) Kern ssp. laevinux (J. Rayn.) Lye, M. montana (J. Rayn.) Lye, M. flexuosa (Böck.) Kern ssp. polyanthemum (Kük.) Lye, Scleria lagoënsis Böck. ssp. canaliculato–triquetra (Böck.) Lye, 5. distans Poiret var. glomerulata (Oliv.) Lye, S. distans Poiret var. chondrocarpa (Nelmes) Lye, S. melanotricha A. Rich. var. grata (Nelmes) Lye, Carex echinochloë Kunze ssp. nyasensis (C. B. Clarke) Lye, C. conferta A. Rich. var. lycurus (K. Schum.) Lye, C. cognata Kunth var. abyssinica (Chiov.) Lye and C. cognata Kunth var. congolensis (Turrill) Lye.     

Comparative ontogeny of perfect and pistillate florets in Senecio vernalis (Asteraceae)

We studied the inflorescence, and in particular ontogeny and development of the florets in Senecio vernalis as a representative member of Asteraceae, using epi-illumination microscopy. Initiation and subsequent development of florets on the highly convex inflorescence apex occur acropetally, except for pistillate ray florets, which show a lag in initiation. Receptacular bracts derive from the receptacular surface after development of all florets. The order of whorl initiation in both disc and ray florets include corolla, androecium and finally the pappus, together with the gynoecium. Development of corolla lobes from a ring meristem occurs in bidirectional order starting from the lateral side, whereas stamens incept unidirectionally from the abaxial side. Concurrently with the inception of two median carpel primordia, a ring meristem develops at the base of the corolla from which pappus bristles differentiate in later stages. Pistillate ray florets show significant differences from perfect disc florets as reflected by the zygomorphic shape of the floral apex and a shift of floral merosity from pentamery to tetramery. Loss of stamens in ray florets occurs due to abortion of primordia after initiation.     

SECRETION AND DEPLOYMENT OF BRISTLES IN MALLOMONAS SPLENDENS (SYNUROPHYCEAE)1

Mallomonas splendens (G. S. West) Playfair has a cell covering of siliceous scales and bristles. Interphase cells bear four anterior and four posterior bristles that each articulate, at their flexed basal ends via a complex of labile fibers (the fibrillar complex), on a specialized body scale (a base-plate scale). Body scales, base-plate scales and bristles are formed independently of each other and at different times in silica deposition vesicles (SDVs) that are associated with one of the two chloroplasts. The fine structure of scale and bristle morphogenesis in M. splendens agrees with that previously described for Synura and Mallomonas. Four new posterior bristles are formed at late interphase with their basal ends towards the cell posterior. The fibrillar complex is formed in situ on the bristle in the SDV. Mature bristles are secreted one by one onto the surface of the protoplast, beneath the layer of body scales, where the basal ends of the bristles adhere to the plasma membrane via the fibrillar complex. The extrusion of posterior bristles and their deployment onto the cell surface was monitored with video. A fine cellular protuberance accompanies the bristles as they are extruded from beneath the scale layer with their basal ends leading. When distant from the cell, the basal ends of the bristles appear attached to the protuberance, possibly by way of their fibrillar complexes. Once bristles are fully extruded, and their tips free in the surrounding environment, the bristle bases are drawn back to the posterior apex of the cell, apparently by the now shortening protuberance. Thus a 180° reorientation of the posterior bristles has been effected outside the cell. Thin-sections of cells that are extruding bristles show a threadlike, cytoplasmic extension of the cell posterior which may be analogous to the protuberance seen in live cells. Four new posterior base-plate scales are secreted after the bristles have reoriented. Scanning electron microscopy indicates that the fibrillar complex is involved in positioning the bristles onto their respective base-plate scales. Anterior bristles are formed in new daughter cells in the same orientation as the posterior bristles; thus they are extruded tip first and no reorientation is required.     

Investigation on Embryology of Anemarrhena asphodeloides

Anemarrhena asphodeloides Bunge is the only species of Anemarrhena in Liliaceae, which possesses three stamens. The flowers in this species have following features: (1) Crystalliferous cells are present in the perianth and the filament. (2) Epidermal cells of filaments and the inner perianth appears verruciform. (3) In longitudinal section, a number of the multicellular hairs were found in the apex of the inner perianth. The above characteristics of Anemarrhena are possibly important and differ from those of the other genera in Liliaceae. The main aim of the present paper is to deal with the female gametophyte and embryogenesis in Anemarrhena. The development of embryo sac is similar to that of Ornithogalum (Tilton et al., 1981), belonging to the Polygonum type, but there is a short embryo sac haustorium at the antipodal end. Before fertilization the two polar muclei fuse into a secondary nucleus. The filiform apparatus was found in the synergid. The early development of proembryo in Anemarrhena is similar to that of Najas (Hu, 1982). After fertilization the zygote has a short stage of dormancy. When the endosperm has 12-16 free nuclei, the first division of the zygote takes place, forming an apical cell and a basal cell. Then the apical cell undergoes transversal divisions 2 or 3 times, forming a line of three to four cells. The basal cell usually does not further divide. The endosperm formation in Anemarrhena is the Helobial type. The small chalazal chamber is usually ephemeral and 2-4-nucleate, while the large micropylar one may be a multi-nucleate before wall formation.     

A monograph of the genus Colignonia (Nyctaginaceae)

Species of the neotropical genus Colignoniu are perennial herbs, subshrubs and lianas from 1 m to c. 15 m tall. The genus ranges from c. 5°N in Colombia to c. 28°S in Argentina and comprises six species. It occurs in the Andean montane rain forest and cloud forest, often in disturbed areas. The flowers are of two types and divide the genus into two sections, viz. Pterocarpae (3 spp) with a 3-lobed perianth, and Colignonia (3 spp) with a 5-lobed perianth. C. pentoptera is described as new. C. biumbellata is reduced to subspecific status under C. parviflora. C. acutifolia , originally described by Heimerl as a variety of C. glomerata , is referred to C. parviflora as a distinct variety of ssp. biumbellata . Several names are reduced to synonymy. The chromosome number 2 n = 34 is recorded for three species (Sect. Colignoniu ) and 2 n= 32 for three species (Sect. Pterocarpae ). The correlation between chromosome numbers and perianth type supports the subdivision of the genus. Considerable morphological variation, correlated with changes in temperature and altitude, was observed in the field and in plants under cultivation. Pollen morphology and relationships to other genera in the Nyctaginaceae are discussed. Colignonia seems most closely related to Mirabilis, Commicarpus, Boerhaaviu , and Pisoniella .     

Selective advantage of ray florets in Scalesia affinis and S. pedunculata (Asteraceae), two endemic species from the Galápagos

The presence of neuter ray florets in species within Asteraceae is generally believed to increase pollinator attraction. In the endemic Galápagos genus Scalesia (Asteraceae) a natural variation in the presence/absence of neuter ray florets is found. To evaluate whether the presence of ray florets plays a selective role on female reproductive success we chose two species of Scalesia, Scalesia affinis that carries ray florets and S. pedunculata that is rayless. On Santa Cruz Island capitula of S. pedunculata were equipped with fake ray florets while others were untouched. On Isabela Island ray florets were removed on half of the capitula of S. affinis. In S. affinis rayed capitula received more pollinators and more pollen, which resulted in a significantly higher embryo production. In S. pedunculata no effect on embryo production was found. The disagreement between the two species may correspond to a difference in visitation frequency, S. pedunculata receiving many more visit than S. affinis. Thus, ray floret development proved beneficial in pollinator-restricted localities.     

Characterization of the common wheat (Triticum aestivum L.) mutation line producing three pistils in a floret

In a normal wheat (Triticum ssp.L.) spike, one floret carries only one pistil that will further develop into one grain after fertilization. The cultivated common wheat (T. aestivum L.) mutation line Three Pistils (TP) carried three pistils in a floret. Although one or two of the pistils died out before seed set in some florets, there were exist many florets that set three seeds. Normally, it was observed that there were one to three seeds in different florets of the same spike. Therefore, this mutation trait could raise considerably the number of grains per spike. The weight of 100 grains in three seeds set florets was lower than that of in one seed set florets. But three seeds set florets were significantly to surpass the one seed set florets in grain(s) weight per floret. Based on these results, the three pistils trait was suggested to be an interesting germplasm resource. Localisation of the gene controlling the three pistils trait was carried out by the method of crossing TP with the Chinese Spring disomic substitutions. F2 population segregation analysis revealed that only the 5B F2 population did not show homogeneity to control population. chi2-test analysis indicated that 5B F2 population, and only this population, was deviated from the Mendelian segregation ratio (3:1). As a conclusion, the gene for three pistils trait was located on chromosome 5B. According to the Recommended rules for gene symbolization in wheat, the name of the dominant gene for three pistils trait in the line TP was suggested as Pis1.     

越北腹露蝗触角感器的扫描电镜观察

应用环境扫描电镜(ESEM)对越北腹露蝗FruhstorferiolatonkinensisWill.触角的外部形态进行观察的结果表明,蝗蝻和成虫触角均分布有以下6种感器,毛形感器、刺形感器、锥形感器、栓锥形感器、腔锥形感器和Bhm氏鬃毛,其中锥形感器有长、短锥之分,腔锥形感器有Ⅰ、Ⅱ型之分。芽孢形感器、盾形感器和钟形感器只限于蝗蝻的触角。成虫触角鞭节末端长锥形感器数量多于蝗蝻;而蝗蝻触角鞭节末端短锥形感器数量多于成虫。成虫触角从第9节开始,蝗蝻触角从第11节开始锥形感器和腔锥形感器的数量明显增多。     

Perianth colour dimorphism is related to germination properties and salinity tolerance in Salsola vermiculata in the Arabian deserts

We investigated the dimorphic perianth colour of Salsola vermiculata and its association with seed germination percentage, interactions with temperature, light, salinity and recovery from prior salinity exposure. Seeds with and without pink and yellow perianth were incubated at three thermal regimes, two photoperiods, and five salinity levels. Germination recovery after salinity exposure was observed on seeds that failed to germinate during the salinity study. The germination percentage and rate were signi?cantly related to the perianth colour, the presence of perianth wings, thermal regimes and photoperiod. The presence of a perianth wing significantly reduced germination percentage and germination rate in both the pink and the yellow morph, but the yellow morph exhibited a higher germination percentage. Perianth wing removal increased germination in saline conditions. With the perianth removed, germination recovery was higher for the pink morph than for the yellow one. We suggest that by providing two different strategies for balancing germination with dormancy during favourable conditions, the presence of two morphs makes S. vermiculata more successful in highly unpredictable desert environments.     

A Study of Floret Development in Wheat (Triticum aestivum L.)

Plants of wheat (Triticum aestlvum L.) cv. Aotea were grownat high or low nitrogen levels and in a natural photoperiodor continuous light. Starting 17–21 days from the double-ridgestage, eight plants from each treatment were sampled every 3days until anthesis, and the two basal, the sixth, and the terminalspikelets were sectioned longitudinally. A developmental scorewas assigned to each floret and rates of development calculated.Continuous light hastened development but reduced the numberof spikelets per ear, while high nitrogen delayed developmentbut increased spikelet numbers. The number of florets initiatedin each spikelet varied within narrow limits, but grain settingdepended strongly on spikelet position and on treatment. Althoughflorets were initiated in acropetal succession, the rate ofdevelopment tended to increase up to floret 4 but then declinedmarkedly. As a result grain setting was confined to basal floretpositions, although the two basal spikelets developed so slowlythat they contributed relatively little to grain yield. Distalflorets degenerated almost simultaneously at or before ear emergence,but those in intermediate positions continued to develop untilafter fertilization in the lower florets. It is argued thatthe spikelet is an integrated system in which correlative mechanismsplay a part throughout the development of the florets.     

番荔枝科两种植物花器官形态发生

用扫描电镜观察了囊瓣木（Saccopetalum prolificum）和刺果番荔枝（Annona muricata）花器官的形态发生过程。刺果番荔枝和囊瓣木花被片均为3轮,其中刺果番荔枝内轮花被片数目为3枚、5枚或7枚。囊瓣木花原基最初为圆锥形,最外轮3枚花被片很快发生,之后中、内轮花被片原基连续发生,3轮花被片互生。此时花原基为六边形。花被片分化完成时,圆球形雄蕊原基沿六边形花原基的6个边螺旋向心发生,最终近轮状排列于花原基上。刺果番荔枝的雄蕊较多（约1000枚）,首先在中轮花被片所对的花原基边缘发生,之后大量雄蕊螺旋状发生。心皮分化的早期阶段,与雄蕊原基很相似,当心皮数目逐渐增多时,不能分辩出发生的顺序。成熟花中,心皮和雄蕊全都被毛覆盖,毛具有粘住传粉滴的作用。     

Changes in Cell Number and Cell Division Activity during Endosperm Development in Allohexaploid Wheat, Triticum aestivum L.

Nuclear or cell number, and the mitotic index, were recordedin endosperms of Triticum aestivum cv. Mardler to test if aparticular stage of endosperm development was critical in determiningthe final grain weight. The basal four florets of emasculatedspikelets (controls), and the third and fourth florets of spikeletswhere the two basal ovaries were removed (ovary-removed), weresampled at various times up to 360 h after hand-pollination.The coenocytic phase in endosperms ended about 84 h after pollinationregardless of both grain position and the treatment. The onsetof the cellular stage was characterized by the final large fluctuationsin the mitotic index reflecting the culmination of the synchronousnuclear division of the coenocytic stage. Thereafter, the mitoticindex fluctuated with smaller amplitudes and, by 216 h afterpollination, was < 1%. Neither floret position in the spikeletnor the treatment affected the pattern of alteration to themitotic index. However, ovary removal from first and secondflorets resulted in significantly heavier grains and higherendosperm cell number in the 3rd and 4th florets compared withthe controls. In all florets, mean endosperm cell number peakedat 280 h but decreased by 360 h after pollination. At this time,the mean cell numbers in endosperms of the 3rd and 4th floretsof ovary-removed spikelets were significantly higher than inthe corresponding endosperms in the controls. Thus, a key contributoryfactor in determining the final endosperm cell number may bethe number of cells which are lost during the late period ofthe cellular stage of endosperm development. Key words: Endosperm cell number, florets, grain weight, mitotic index, Triticum aestivum     

RAPD and internal transcribed spacer sequence analyses reveal Zea nicaraguensis as a section Luxuriantes species close to Zea luxurians

Genetic relationship of a newly discovered teosinte from Nicaragua, Zea nicaraguensis with waterlogging tolerance, was determined based on randomly amplified polymorphic DNA (RAPD) markers and the internal transcribed spacer (ITS) sequences of nuclear ribosomal DNA using 14 accessions from Zea species. RAPD analysis showed that a total of 5,303 fragments were produced by 136 random decamer primers, of which 84.86% bands were polymorphic. RAPD-based UPGMA analysis demonstrated that the genus Zea can be divided into section Luxuriantes including Zea diploperennis, Zea luxurians, Zea perennis and Zea nicaraguensis, and section Zea including Zea mays ssp. mexicana, Zea mays ssp. parviglumis, Zea mays ssp. huehuetenangensis and Zea mays ssp. mays. ITS sequence analysis showed the lengths of the entire ITS region of the 14 taxa in Zea varied from 597 to 605 bp. The average GC content was 67.8%. In addition to the insertion/deletions, 78 variable sites were recorded in the total ITS region with 47 in ITS1, 5 in 5.8S, and 26 in ITS2. Sequences of these taxa were analyzed with neighbor-joining (NJ) and maximum parsimony (MP) methods to construct the phylogenetic trees, selecting Tripsacum dactyloides L. as the outgroup. The phylogenetic relationships of Zea species inferred from the ITS sequences are highly concordant with the RAPD evidence that resolved two major subgenus clades. Both RAPD and ITS sequence analyses indicate that Zea nicaraguensis is more closely related to Zea luxurians than the other teosintes and cultivated maize, which should be regarded as a section Luxuriantes species.     

Taxonomic Studies on the Nocturnal Flowering Group of Hemerocallis (Liliaceae) from China

The nocturnal-flowering group of Hemerocallis was treated as including three separate species, H．lilioasphodelus,H.citrina and H．minor in the Florae Reipublicae Popularis Sinicae Vol．14(1980)．However it is difficult to distinguish them from one another by a single feature,such as the flower number,length of perianth tube,diameter of tuberous roots,for they are strongly overlapping．In the present paper,numerical analysis was made of nine morphological characters and karyotype divergences which are of taxonomic significance as shown in the study of H． fulva and its two varieties (Xiong and Chen,1992),based on dry and living materials from China．In addition,geographical distribution pattern of the three taxa studied shows that they seem to be different geographical races or allopatric ecotypes in a topocline,since they inhabit a climate gradient from warm and moist to cold and drought condition．As a result,the present authors tend to consider it more reasonable to treat them as a single species,H．lilioasphodelus,with three subspecies,that is, H．lilioasphodelus ssp．lilioasphodelus,H．lilioasphodelus ssp． citrina (stat．nov) and H．lilioasphodelus ssp．minor(stat．nov．)     

直立百部的一个新异名

根据对直立百部Stemona sessilifolia（Miq．）Miq．大量标本的研究和野外调查及引种栽培观察,结合对山东百部Stemona shandongensis D．K．Zang模式标本产地的调查,发现直立百部的形态性状是多变的。研究表明它的习性受生境影响而多变,从直立半灌木到蔓生都有;叶型多变;花通常出自叶腋,而花梗有时与叶柄,甚至主脉合生;内轮花被片大多明显大于外轮。山东百部的形态性状处于直立百部的变异范围内,因此作为独立的种是难以成立的,应处理为直立百部的新异名。     

Eleocharis khandwaensis sp. nov. (Cyperaceae) from the Madhya Pradesh,India

A new species, Eleocharis khandwaensis Mujaffar, Chandore & S. R. Yadav is described from the Bamangaon village of Khandwa district in Madhya Pradesh state, India. This species belongs to Eleocharis subgen. Limnochloa (P. Beauv. ex Lestib.) Torr. and it is similar to E. lankana T. Koyama but differs in having stolons, weak bristles spinules of perianth, achenes with annulate apex with a short neck, truncate achene base, dark brown to black coloured achenes and nut surface epidermal cells that are isodiametrically hexagonal to pentagonal. Eleocharis khandwaensis grows in ponds along road sides in the Bamangaon and Tirandaz villages.     

Description of Nosopsyllus (N.) atsbi n. sp. (Siphonaptera: Ceratophyllidae) from Ethiopia, and revision of the related species N. (N.) incisus (Jordan & Rothschild, 1913); biogeographical discussion

We describe a new Nosopsyllus s. sto., N. atsbi, from the north of Ethiopia, that shows phyletic similarities with N. incisus (Jordan & Rothschild, 1913), a species from the oriental part of the afrotropical region. This led us to reconsider the classification of the incisus populations based on the unique criteria of telomere's setation (three robust marginal bristles, instead of the two typically present in members of this genus and subgenus). It appears that N. incisus s. sto. occurs in north-eastern Democratic Republic of the Congo, Kenya, Burundi and Tanzania. In the north and south of this region (respectively central Ethiopia, on one hand, Zambia and Malawi, on the other hand), two taxa are morphologically distinct and we erect them here to the rank of subspecies: Nosopsyllus (N.) incisus traubi n. ssp. and N. (N.) incisus lewisi n. ssp. Actually, four taxa are in "incisus complex", namely: N. atsbi n. sp., N. incisus traubi n. ssp., N. incisus incisus (Jordan & Rothschild, 1913), and N. incisus lewisi n. ssp.