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* Premise of the study: Storage oil (triacylglycerol) accumulates in tissues such as the embryo and endosperm of seeds and the fruit mesocarp, but seldom in underground organs. As a rare exception, cultivated variants of yellow nutsedge (Cyperus esculentus) contain high amounts of both oil and starch in the mature tubers. * Methods: Biochemical analyses and light and electron microscopy were used to study the accumulation patterns of storage nutrients in developing nutsedge tubers. * Key results: During the initial phase of tuber development, the conducting rhizome tissue is transformed into a storage compartment, then massive storage reserves accumulate in the tuber. At the beginning of tuber development, a large sugar load coincided with the onset of starch accumulation. Oil accumulation started later, concomitant with a substantial drop in the sugar content. Initially, oil accumulated at a lower rate compared to starch, but the rate later increased; after 6 wk, oil made up 24% of tuber dry mass, while starch made up 32%. Protein concentration changed only a small amount throughout this development. Oil and starch accumulated in the same cells throughout the tubers in a sequential fashion during tuber development. * Conclusions: The developmental pattern in the build up of storage nutrients in the tubers highlights nutsedge as a novel model plant, having potential to significantly widen our understanding on how synthesis of storage reserves, and in particular oils, is regulated and directed in nonseed tissues such as tubers and roots. Key words: carbon allocation; Cyperaceae; Cyperus esculentus; oil; starch; sugar; storage reserve; triacylglycerol; tuber. doi: 10.3732/ajb.1000200

Byline: Osamu Ueno (1), Masataka Wakayama (1,2) Keywords: Amphibious plant; C.sub.3 and C.sub.4 photosynthetic enzymes; C.sub.4 pathway; Eleocharis retroflexa ssp. chaetaria; Immunogold localization; Kranz anatomy Abstract: The amphibious leafless sedge Eleocharis retroflexa ssp. chaetaria expresses C.sub.4-like biochemical characteristics in both the terrestrial and submerged forms. Culms of the terrestrial form have Kranz anatomy, whereas those of the submerged form have Kranz-like anatomy combined with anatomical features of aquatic plant leaves. We examined the immunolocalization of C.sub.3 and C.sub.4 enzymes in culms of the two forms. In both forms, phosphoenolpyruvate carboxylase pyruvate, Pi dikinase and NAD-malic enzyme were compartmentalized between the mesophyll (M) and Kranz cells, but their levels were somewhat reduced in the submerged form. In the terrestrial form, ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) occurred mainly in the Kranz cells, and weakly in the M chloroplasts. In the submerged form, the rubisco occurred at higher levels in the M cells than in the terrestrial form. In both forms, the C.sub.4 pattern of enzyme expression was clearer in the M cells adjacent to Kranz cells than in distant M cells. During the transition from terrestrial to submerged conditions, the enzyme expression pattern changed in submerged mature culms that had been formed in air before submergence, and matched that in culms newly developed underwater. It seems that effects of both environmental and developmental factors overlap in the C.sub.4 pattern expression in this plant. Author Affiliation: (1) Plant Physiology Department, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan (2) Department of Biochemistry and Molecular Biology, Faculty of Science, Saitama University, Saitama 338-8570, Japan Article History: Registration Date: 25/08/2004 Received Date: 01/06/2004 Accepted Date: 18/08/2004 Online Date: 05/10/2004

Byline: Okihito Yano (1), Teruo Katsuyama (2), Hiromi Tsubota (3), Takuji Hoshino (1) Keywords: Chromosomal evolution; Cyperaceae; Diffuse centromeric chromosome; Eleocharis; ITS phylogeny; Karyotype Abstract: ITS sequence data were used to estimate the phylogeny of 24 Japanese Eleocharis species and to make karyomorphological observations on 19 of these taxa. Two major clades were identified in Japanese Eleocharis molecular phylogenetic trees: (1) one including all species of section Limnochloa, and (2) another comprising two sections, Pauciflorae and Eleocharis. Phylogenetic analysis including both Japanese and North American species also shows strong support for monophyly of the Mutatae/Limnochloa clade. The width of the spikelets in the species Mutatae/Limnochloa is the same as that of the culms, indicating that the relative widths of spikelets and culms are useful characteristics for classification. Two major clades were supported by karyomorphological data. All taxa of section Limnochloa had very small chromosomes, while sections Pauciflorae and Eleocharis had large chromosomes. The basic chromosome number of sections Eleocharis and Pauciflorae is thought to be x=5. Chromosomal evolution in the genus Eleocharis with diffuse centromeric chromosomes may be caused by both aneuploidization and polyploidization. Our data suggest that a 3-bp insertion near the 3 end of the 5.8S gene is useful for intrageneric delimitations of the genus Eleocharis. Author Affiliation: (1) Department of Biosphere-Geosphere System Science, Graduate School of Informatics, Okayama University of Science, 1-1 Ridaicho, Okayama 700-0005, Japan (2) Kanagawa Prefectural Museum of Natural History, Kanagawa, Japan (3) Department of Biological Science, Graduate School of Science, Hiroshima University, Hiroshima, Japan Article History: Registration Date: 13/08/2004 Received Date: 30/06/2004 Accepted Date: 09/08/2004 Online Date: 15/09/2004

The purpose of our research was to determine why seeds of Schoenoplectus hallii germinate only in some wet years. Seeds mature in autumn, at which time they are dormant. Seeds come out of dormancy during winter, if buried in nonflooded, moist soil, but they remain dormant if buried in flooded soil. Nondormant seeds require flooding, light, and exposure to ethylene to germinate. One piece of apple in water (1/12 of an apple in 125 mL of water in a glass jar for a depth of 5 cm) or a 1-[micro]mol/L solution of ethephon elicited very similar (high) germination percentages and vigor of seedlings. Apple, which was shown to produce ethylene in the air space of the jar, was used in a series of experiments to better understand germination. Seeds germinated to 72% if apple was removed from the water after 1 d of incubation, and they germinated to 97% if seeds were washed and placed in fresh water after 3 d of exposure to apple. No seeds germinated in control with no apple. Seeds incubated in apple leachate for 5 d and then transferred to filter paper moistened with distilled water germinated to 90%. Minimum depth of flooding in apple leachate (no soil in jars) for optimum germination was [greater than or equal] 3 cm. Buried seeds of S. hallii exhibited an annual conditional dormancy/nondormancy cycle. Regardless of the month in which seeds were exhumed, they germinated to 59-100% in light in water with apple at daily alternating temperature regimes of 25[degrees]/15[degrees], 30[degrees]/15[degrees], and 35[degrees]/20[degrees]C, but germination at 20[degrees]/10[degrees]C (and to some extent at 15[degrees]/6[degrees]C) tended to peak in autumn to spring. Thus, seeds can germinate throughout the summer if flooded (ethylenc production) and exposed to light. An ethylene cue for germination serves as a 'flood-detecting' mechanism and may serve as an indirect signal that water is available for completion of the life cycle and competing species are absent. Key words: Cyperaceae; ethylene; flooding requirement; germination cue; light requirement; Schoenopleetus hallii; seed dormancy-breaking requirements; seed germination requirements.

The effect of intraspecific competition and nutrient supply on the endangered northeastern bulrush, Scirpus ancistrochaetus, was examined in a full-factorial greenhouse experiment. Seedlings were exposed to 4 densities (1, 5, 10 or 25 plants/pot) and 3 nutrient concentrations (3, 25 or 50% of full strength) for 9 wk. Height, mass and survival generally decreased with increasing density. Root to shoot ratio (R:S) increased with density, indicating that competition primarily involved belowground resources. Nutrient concentration significantly affected average plant height, total mass and R:S but did not affect survival. Plant height and total mass generally increased with increasing nutrient concentration, whereas R:S decreased. In general, the negative effect of intraspecific competition on plant height and total mass was greatest at the highest nutrient concentration, confirming that the intensity of intraspecific competition increases with resource supply in this species. Neither density nor nutrient concentration affected the population distribution of plant sizes in densities over 1 plant/pot, suggesting that size hierarchies, and therefore asymmetric competition, are not important during seedling growth in this species. Information gained from this study can be used towards understanding seedling establishment in the field and, in turn, towards effective management and reintroduction of this endangered species., INTRODUCTION Northeastern bulrush, Scirpus ancistrochaetus Schuyler, is a perennial emergent sedge (Schuyler, 1962) typically found in small, seasonal, palustrine wetlands which are frequently isolated in the landscape. It ranges from [...]

Field studies as well as principal components analysis and analyses of variance of specimen measurements revealed morphologic variation within Carex willdenowii correlated with differences in geographical distribution and habitat characteristics. C. willdenowii is actually a complex of three species, C. basiantha Steudel, C. willdenowii Willdenow, and C. superata Naczi, Reznicek, & B.A. Ford, sp. nov. Carex basiantha is a calciphile of moist forests in the southern United States. It has relatively long culms and terminal spikes with long staminate portions, Carex willdenowii is a calcifuge of dry forests in the northeastern United States and immediately adjacent Canada. It has relatively long culms and terminal spikes with short staminate portions. Carex superata is a facultative calciphile of moist to dry forests of the southeastern United States. It has relatively short culms and terminal spikes with long staminate portions. Synonymies, typifications, descriptions, and citations of representative specimens are provided for each species, along with an identification key. The recognition of previously unsuspected diversity in a species from a region with a relatively well-known flora suggests the systematics of other common, widespread, and morphologically divergent species should be investigated. Key words: Carex section Phyllostachys; Cyperaceae; phytogeography; principal components analysis; species delimitation.

An anatomical survey of anthers of the Poaceae and Cyperaceae and two related families, the Restionaceae and Flagellariaceae, was conducted to determine the taxonomic distribution and possible phylogenetic significance of pollen arrangement. An unusual pollen arrangement was known from a small number of taxa in the Poaceae and Cyperaceae, in which a single, uniseriate cylinder of pollen grains is arranged in the anther locule such that each grain is in contact with the tapetum (termed here 'peripheral' pollen). This contrasts with the prevailing arrangement in other angiosperms in which the locule contains a relatively large number of pollen grains in no special configuration, with many interior grains that never touch the tapetum (termed here 'central' pollen). A total of 48 species in these four families was examined in this study, and observations on pollen arrangement for numerous additional species in these families were gleaned from the literature. We confirm that the peripheral arrangement is predominant in Poaceae and Cyperaceae, although both families also include species with central pollen, whereas only central pollen is found in Restionaceae and Flagellariaceae. In the peripheral arrangement, the pore of the pollen grain or pseudomonad, when observed, is in contact with the tapetum, but it has not been definitively demonstrated that this is always the case. Peripheral pollen in the Poaceae and Cyperaceae is nonhomologous because of the presence of pseudomonads in the latter family. It remains unexplained why peripherally arranged pollen or pseudomonads, with the attendant reduction in the number of pollen grains, should be associated with anemophily in these two families. Key words: anatomy; anther; Centrolepidaceae; Cyperaceae; Juncaceae; Poaceae; pollen; Restionaceae.

Delta(13)C measurements in sedges and mosses with high temporal resolution help reconstruct CO2(sub a) which gives information on past CO2(sub a) changes in the atmosphere. Comparison of past climatic changes and CO2 help analyze the effect of future atmospheric CO2 changes on the global climate system. Delta(13)C of mosses depend on atmospheric CO2 and water, and this factor enhances the information contained in ice core data.

A suite of characteristics of Cyperus plukenetii, which facilitate zoochory (animal dispersal), is described and illustrated. Dispersal experiments with C. plukenetii show an average of 46.4 spikelets initially adhered to the human disperser's clothing. Of these, 38.8% were transported at least 10 m from the source, and 15.2% were dispersed at least 100 m. Data about plant height (arithmetic mean of sample = 65 cm, range = 20-121) taken from living populations and from herbarium specimens indicate that a variety of mammals, and perhaps birds, may potentially function as dispersal agents of C. plukenetii.

1. Allocation of biomass and nitrogen were studied for 1 year in experimental populations of Carex diandra, C. rostrata and C. lasiocarpa (species from mesotrophic fens) and C. acutiformis (a species from eutrophic fens). These species were grown at two levels of N supply (3 center dot 3 and 20 center dot 0 g N m to the -2 year to the -1, respectively). 2. At low N supply, total biomass did not differ between the species. At high N supply, the total biomass of C. lasiocarpa and C. acutiformis ('high-productive species') significantly exceeded that of C. diandra and C. rostrata ('low-productive species'). In all species, percentage nitrogen allocation to the leaves exceeded percentage biomass allocation to the leaves. 3. The high-productive species had a higher shoot:root ratio, a higher percentage biomass allocation to the leaves (leaf weight ratio, LWR), a higher total nitrogen content and a higher percentage nitrogen allocation to the leaves than the low-productive species. However, the low-productive species had higher leaf nitrogen concentrations (on a weight basis) than the high-productive species. 4. Parameters which are related to light interception, such as the specific leaf area (SLA: m squared of leaf per kg of leaf), the leaf area ratio (LAR: m squared of leaf per kg of plant), the leaf area index (LAI: m squared of leaf per m squared of soil) and the ratio between total leaf area and total root length, did not differ consistently between the high-productive and the low-productive species. 5. Compared with the high-productive species, the low-productive species invested relatively more biomass and nitrogen in plant parts which contribute to the acquisition of below-ground resources. 6. At low N supply, there was a decrease in all species of the shoot:root ratio, LWR, LAR, LAI, and the ratio between total leaf area and total root length. 7. The rank order of potential productivity of the species in this study did not match the rank order of nitrogen availability in their natural habitat. It is suggested that the distribution of these species is not only determined by their potential productivity, but also by specific demands on the water chemistry and by their competitive ability.

The first reports of Carex hybrids in North America appeared in the middle and late 1800's. By the early 1900's and up to the middle 1900's there was disagreement among the influential North American botanists regarding the extent to which hybrids existed. Those who recognized hybridization in Carex have been largely supported by recent studies, but only a small proportion of the reported hybrids are well documented. An understanding of hybridization in the genus is very important to systematic research and routine identification, as well as to the study of evolution and ecology. A total of 253 Carex hybrids have been reported from North America, the greatest number of hybrids occurring in the northeast, where recent glaciation and overlapping flowering periods are probably among the causal factors. Based on current reports, hybrids are much more prevalent in subgenus Carex than in subgenus Vignea. Field studies and cultivation have proven useful in determining hybrid parentage and delimiting morphological variation, respectively. Both reproductive and vegetative characters as well as anatomical and micromorphological characters have proven taxonomically useful. Cytological studies have documented meiotic irregularities in Carex hybrids and intermediate chromosome numbers. Variation in the meiotic anomalies is apparently associated with the relationship of the parents and with differences in chromosome number. Carex hybrids are largely sterile but some restoration of fertility is evident in backcrosses. Experimental hybridization, flavonoid chromatography, enzyme electrophoresis, phenological characteristics, developmental anomalies and host-parasite relationships have all been underexploited in the characterization of hybrids. A cross-referenced list of North American Carex hybrids is included, along with a list of hybrids not yet reported for North America involving circumpolar species.

(1) The relative magnitudes of environmental vs. genetic influences on the growth of Scirpus americanus and Scirpus maritimus were examined in an intertidal marsh on the Fraser River Delta, British Columbia. Intraspecific comparisons at the high and low parts of an elevational gradient were made for shoot, inflorescence, root, rhizome and corm mass over a 16-month period. (2) S. americanus plants on the high marsh had greater shoot densities, flowering frequencies, above- and below-ground masses than plants growing on the low marsh. Shoot density of S. maritimus was highest on the low marsh but its flowering frequency, and above- and below-ground masses were greatest on the high marsh. At all sites sampled, vegetative reproductive effort exceeded sexual reproductive effort; within each species, total reproductive effort on the high marsh exceeded that measured on the low marsh. (3) Shoot growth rates were calculated after controlling for below-ground mass and the duration of tidal exposure. For both species, low-marsh stands had higher shoot growth rates per gram below-ground mass per hour of tidal exposure than high-marsh stands, but shoot mass [m.sup.-2] was greatest on the high marsh. Enhanced plant mass on the high marsh is associated with larger below-ground reserves, but is ultimately a product of prolonged aerial exposure. (4) Reciprocal field-transplant experiments indicated that the high- and low-marsh populations of S. americanus and S. maritimus consist of different genotypes which show similar phenotypes when grown in a common environment. Genotypes moved into new environments grew as well as the residents, suggesting that there is no local genetic differentiation.

Carex section Acrocystis (Cyperaceae) traditionally has included ca. 45 species. Recent studies have suggested that a 'core' group of Acrocystis species forms a monophyletic group, while other species are more closely related to other sections. This core group includes all North American Acrocystis species and some but not all Eurasian members. Taxonomists have recognized several species complexes in North American Acrocystis, with several 'orphan' species not delt with in these species complexes. The complexes that have been defined include the 'Carex pensylvanica complex,' the 'Carex nigromarginata complex,' the 'Carex deflexa complex,' and the 'Carex umbellata complex'. Taxa not included in these complexes are Carex novae-angliae, C. turbinata, C. leucodonta, C. communis, C. globosa, C. brainerdii, and C. serpenticola. How these complexes and orphan species are related has not been addressed explicitly, and none of the North American species have been explicitly compared with Eurasian or South American members of Acrocystis, with few exceptions. The study presented here explores relationships within North American members of Carex section Acrocystis and related Eurasian species and addresses biogeographic patterns of diversification using nuclear Adh genic regions and the nrDNA ITS region.

Bioassays for allelochemical toxicity of aboveground Juncus effusus tissues were conducted with seeds and seedlings of Eleocharis obtusa and Scirpus cyperinus, two emergent sedge species (Cyperaceae) found sympatric with J. effusus, and with seeds and seedlings of J. effusus itself to evaluate potential autotoxicity. Bioassays were performed under controlled, axenic conditions with aqueous shoot extract treatments simulating in situ dissolved organic carbon concentrations. With respect to the two sedge species, neither shoot development nor seedling biomass accrual was significantly suppressed by lyophilized whole extracts from J. effusus. Although the extracts induced no significant reduction in growth of E. obtusa or S. cyperinus, biomass-specific chlorophyll a concentration was significantly reduced in E. obtusa seedlings. In contrast, seedlings of J. effusus exhibited significant reductions of biomass and chlorophyll a concentrations, and seedling shoot development was retarded in response to leachate exposure. Results of the present study suggest that J. effusus seedlings possess autotoxic sensitivity to extracts of dead, aboveground tissues of adult plants. Key words: allelochemical interactions; allelopathy; autotoxicity; Cyperaceae; Juncaceae; Juncus effusus.

Seasonal changes in leaf nitrogen distribution were examined in the canopy of a Carex acutiformis stand in a wet meadow area. Although there was a tendency for leaf nitrogen concentration to decrease with increasing leaf age in any one layer of the canopy, nitrogen concentration increased significantly with plant height despite increasing age of leaf portions higher in the canopy. This suggests a predominant effect of the light climate on the nitrogen distribution within the canopy. During the growing period, standing crop dry mass increased significantly, while the increase in the standing crop of nitrogen was marginal. The amount of nitrogen decreased in the lower layers and increased in the upper layers, and a strongly decreasing gradient of nitrogen concentration developed from the top to the bottom of the canopy. It is suggested that this gradient resulted mainly from leaf tips with high nitrogen concentrations being lifted to higher positions because of growth at the base, with some retranslocation of nitrogen downwards from senescing tips to active parts. The distribution of nitrogen concentration became less uniform during the growing period, thus supporting the prediction that nitrogen concentration should become less uniformly distributed with development of the canopy.

We studied 18 of the over 50 sedge species (Cyperaceae: Carex) that occur in a 1200 hectare tract of old growth forest in southern Quebec. The sedges ranged from common to rare at both the site and more generally within their geographic ranges. We grew seedlings of each species under poor versus rich nutrient regimes and assessed interspecific differences in rates of growth, gas exchange, foliar characteristics, and biomass allocation. The plastic responses to the contrasting growth regimes varied among the species and also from trait to trait. Some traits (specific leaf mass) showed little plasticity, others had consistent plastic responses across all species (tillering rate), and still others had qualitatively and quantitatively different plastic responses among the species (root:shoot ratio, photosynthetic capacity). The degree of plasticity was not correlated with the abundance of species at the site. Instead the correlates of local abundance were with species characteristics averaged across the two test environments (a measure of versatility), especially the root:shoot ratio and specific leaf mass. This suggests that the different sedges are to some degree specialized to distinct microenvironments, and that the relative abundance of these microenvironments determines local distribution and abundance more than any more generalist capacity conferred by plasticity.

Four variants of Kranz anatomy occur in the Cyperaceae. Three of these anatomical types (fimbristyloid, chlorocyperoid, and eleocharoid) are unique among taxa with [C.sub.4] photosynthesis in that the photosynthetic carbon reduction tissue (PCR, functional equivalent of bundle sheath) is located within the vascular strand and is separated from the primary carbon assimilation tissue (PCA, positional equivalent of mesophyll) by the mestome sheath layer. In the fourth anatomical type, rhynchosporoid, PCR tissue is located in the position of the mestome sheath. In this study, we compared two aspects of development of PCR and PCA tissues in representatives of the [C.sub.3] and [C.sub.4] types: (1) ontogenetic derivation and (2) cellular differentiation. Analysis of the planes of cell division associated with procambial strand formation indicated that PCR tissue is always derived from the procambium, while PCA tissue is derived from the ground meristem. These cell lineages remain distinct after the initial organization of vascular strands. Analysis of cell differentiation using accumulation of cell-type-specific photosynthetic enzymes as markers of differentiation indicated that, with one exception, a low level of non-cell-specific enzyme accumulation preceded abundant and cell-specific accumulation of photosynthetic enzymes at the distal end of the leaf elongation zone. Enzyme accumulation coincided spatially (and temporally) with structural aspects of cell differentiation. Previous cladistic analyses have indicated that these anatomical types represent separate evolutionary origins of the [C.sub.4] pathway, and the differences in developmental pathways observed here reflect these independent origins from [C.sub.3] ancestors. Key words: [C.sub.4] photosynthesis; cell differentiation; cell lineage; Cyperaceae; Kranz anatomy; PEPCase; RuBPCase.

Spatial patterns of mature anatomy differ among [C.sub.4] representatives of Cyperaceae, Poaceae and a number of dicot families. Temporal aspects of cell differentiation and the accumulation of cell-specific enzymes also differ among these groups, as well as among different biochemical and anatomical types within each group. Ontogenetic studies show that, once procambial meristems become discrete lineages, the developmental pathways of primary carbon assimilation (PCA) and photosynthetic carbon reduction (PCR) cells are distinct. Ontogenetic origins were analyzed using serial transverse sections of dissected shoot apices embedded in Epon resin and examined at the light microscope level. The patterns of formative divisions were observed and used to infer cell lineage relationships and to determine the timing of tissue ontogeny. In the [C.sub.4] Cyperaceae species, Pycreus polystachyos (NADP-ME biochemical type, chlorocyperoid anatomical type, PCR in the position of vascular parenchyma) and Eleocharis retroflexa (NAD-ME biochemical type, eleocharoid anatomical type, PCR between metaxylem and mestome sheath), the PCR tissue originates from internal procambial layers. In contrast, the PCR tissue in Rhynchospora affinis (NADP-ME biochemical type, rhynchosporoid anatomical type, PCR in the position of mestome sheath) is ontogenetically derived from the peripheral layer of procambium. Immunolocalization studies indicate that in these [C.sub.4] Cyperaceae species the cell specific accumulation of the photosynthetic enzyme RuBPCase in PCR tissue occurs early, while the accumulation of PEPCase in PCA tissue occurs late. Accumulation of PEPCase occurs after cell structural differentiation, a temporal pattern of cell specific enzyme accumulation that differs from previously examined representatives of both [C.sub.4] Poaceae and [C.sub.4] dicots. Despite differences in spatial relationships of PCA and PCR tissue in mature leaves, and differences in the temporal pattern of enzyme accumulation among different [C.sub.4] groups, the key features of [C.sub.4] leaf anatomy are always achieved by leaf maturity.