Cyperus prophyllatus: An endangered aquatic new species of Cyperus L. (Cyperaceae) with a exceptional spikelet disarticulation pattern among about 950 species, including molecular phylogenetic, anatomical and (micro)morphological data.

Cyperus prophyllatus, an endangered new species of Cyperus (Cyperaceae) from an aquatic ecosystem of the Atlantic Forest, Espírito Santo State, southeastern Brazil, is described and illustrated. The spikelet morphology of Cyperus prophyllatus is unique among the c. 950 species of Cyperus in having both a conspicuous spikelet prophyll and a corky rachilla articulation, which remain persistent at the base of the spikelet after disarticulation. Our molecular phylogenetic data support the placement of C. prophyllatus in the C3 Cyperus Grade and more precisely in the clade representing Cyperus sect. Oxycaryum, which also includes C. blepharoleptos and C. gardneri. Anatomical and (micro)morphological analyses corroborate the phylogenetic results, provide a better understanding of ecology and taxonomy, as well as reveal compatibility of structures with survival and dispersion in aquatic environments. A distribution map, table with distinctive characters of allied species, and conservation status are made available.

Hyperspectral Classification of Cyperus esculentus Clones and Morphologically Similar Weeds.

Cyperus esculentus (yellow nutsedge) is one of the world's worst weeds as it can cause great damage to crops and crop production. To eradicate C. esculentus, early detection is key-a challenging task as it is often confused with other Cyperaceae and displays wide genetic variability. In this study, the objective was to classify C. esculentus clones and morphologically similar weeds. Hyperspectral reflectance between 500 and 800 nm was tested as a measure to discriminate between (I) C. esculentus and morphologically similar Cyperaceae weeds, and between (II) different clonal populations of C. esculentus using three classification models: random forest (RF), regularized logistic regression (RLR) and partial least squares-discriminant analysis (PLS-DA). RLR performed better than RF and PLS-DA, and was able to adequately classify the samples. The possibility of creating an affordable multispectral sensing tool, for precise in-field recognition of C. esculentus plants based on fewer spectral bands, was tested. Results of this study were compared against simulated results from a commercially available multispectral camera with four spectral bands. The model created with customized bands performed almost equally well as the original PLS-DA or RLR model, and much better than the model describing multispectral image data from a commercially available camera. These results open up the opportunity to develop a dedicated robust tool for C. esculentus recognition based on four spectral bands and an appropriate classification model.

Effect of fire on a monodominant floating mat of Cyperus giganteus Vahl in a neotropical wetland.

The rhizomatous Cyperus giganteus, abundant in the Pantanal wetland, can dominate extense floodable areas as monodominant communities. The Jacadigo lake has a large area of C. giganteus, where we performed an evaluation on community structure during two months in 2010, before it was hit by a wildfire which top-killed the vegetation, compared to ten months post-fire. We utilized 40 plots of 1m × 1m, along permanent trails, assessing two strata: the upper, near the inflorescence of adult plants, and the lower, close to the water level. Our results show that fire does not affect dominance of C. giganteus, as it maintained the same cover as before fire; species richness is not much altered either - 28 before fire and 34 thereafter. Fire changed the floristic composition, due to the annual variation of species and the ability of some plants to colonize gaps and to regrow after fire from underground organs and seeds. The stratification of the vegetation with characteristic species of upper and lower strata was similar after fire.

Effect of fire on a monodominant floating mat of Cyperus giganteus Vahl in a neotropical wetland / Efeito do fogo sobre uma comunidade monodominante de Cyperus giganteus Vahl em uma área úmida neotropical

The rhizomatous Cyperus giganteus, abundant in the Pantanal wetland, can dominate extense floodable areas as monodominant communities. The Jacadigo lake has a large area of C. giganteus, where we performed an evaluation on community structure during two months in 2010, before it was hit by a wildfire which top-killed the vegetation, compared to ten months post-fire. We utilized 40 plots of 1m × 1m, along permanent trails, assessing two strata: the upper, near the inflorescence of adult plants, and the lower, close to the water level. Our results show that fire does not affect dominance of C. giganteus, as it maintained the same cover as before fire; species richness is not much altered either - 28 before fire and 34 thereafter. Fire changed the floristic composition, due to the annual variation of species and the ability of some plants to colonize gaps and to regrow after fire from underground organs and seeds. The stratification of the vegetation with characteristic species of upper and lower strata was similar after fire.

A planta rizomatosa Cyperus giganteus, encontrada no Pantanal, pode dominar extensas áreas inundáveis, formando uma comunidade monodominante chamada localmente de pirizal. A lagoa do Jacadigo, situada na sub-região de Nabileque, possui uma extensa área de pirizal onde foi realizada uma avaliação na estrutura da vegetação durante dois meses no período de 2010, antes de ser atingida por um incêndio que causou perda da cobertura aérea da vegetação e foi comparada com 10 meses de avaliação pós-fogo. Com indicações na literatura de que o rizoma da planta pode favorecer a espécie através de rebrotamento após um incêndio, o objetivo deste trabalho foi avaliar as variações na estrutura da vegetação de pirizal após um evento de fogo. Foram utilizadas 40 parcelas não fixas de 1m × 1m e alocadas sistematicamente através de trilhas avaliando dois estratos: o superior, próximo a inflorescência dos adultos e o inferior, próximo a lâmina d’água. Nos dois meses logo após o fogo, devido ao tamanho reduzido nos indivíduos de C. giganteus foi avaliado apenas um estrato denominado total. Os resultados mostram que o fogo não afeta a dominância de C. giganteus, que se mantém na mesma faixa de cobertura do período anterior ao fogo; a riqueza de espécies não é alterada, 28 no período anterior ao fogo e 34 no período posterior. Após o incêndio, a estrutura da comunidade sofre alteração na composição florística, devido a mudança anual de espécies e a capacidade que certas plantas possuem em colonizar clareiras e rebrotar após o fogo por meio de órgãos subterrâneos e sementes. A estratificação da vegetação com espécies características de estrato superior e inferior se manteve após o fogo, porém com diferença menos acentuada entre as espécies.

A molecular survey concerning the origin of Cyperus esculentus (Cyperaceae, Poales): two sides of the same coin (weed vs. crop).

BACKGROUND AND AIMS: Cyperus esculentus is widespread in tropical and temperate zones and is also present in cooler regions. It is used as a crop plant, but it also occurs in the wild and as a weed. As a consequence of its ecological plasticity, C. esculentus has remarkable variability, with several morphotypes. Four wild-type varieties are presently recognized, in addition to the cultivated form. This study investigates the phylogenetic position and biogeography of C. esculentus with the objective of contributing new data to increase the understanding of its evolutionary history. METHODS: Genealogical relationships among genotypes were inferred by using plastid DNA haplotype and nuclear ribosomal (nr) DNA ribotype sequences for 70 specimens either collected in the field or obtained from herbaria. Statistical dispersal-vicariance (S-DIVA) and Bayesian binary method (BBM) analyses were used to reconstruct the possible ancestral ranges of C. esculentus. In order to determine the age of C. esculentus, a time-measured phylogenetic analysis was performed. KEY RESULTS: Considerable variation between the chosen nuclear and plastid markers was detected (27 ribotypes vs. six haplotypes). No geographical structure was displayed among the haplotypes, but information on the dispersal pattern may be deduced. Two types of ribotypes were detected in nrDNA, with an evident geographical segregation into an Old World group and a polymorphic New World group. Both S-DIVA and BBM analyses suggested a biogeographical history in which dispersal from the African region has been crucial in shaping the current distribution pattern of C. esculentus. The most recent common ancestor between C. esculentus races has an age of 5.1 million years (95 % highest posterior density 2.5-10.2). CONCLUSIONS: The molecular analysis provides novel insights into the evolutionary history of C. esculentus. The results have various taxonomic and phylogenetic implications, including a hypothesis on the origin and phylogeography of this species, which probably originated in the late Cenozoic in Africa, and reached the Americas repeatedly, independently of Columbian exchanges.

Cloning and characterization of ADP-glucose pyrophosphorylase small subunit gene in Cyperus esculentus (yellow nutsedge).

ADP-glucose pyrophosphorylase (ADPGlcPPase) controls the first committed step of starch synthesis by catalyzing the biosynthesis of ADP-glucose from glucose-phosphate and ATP. It is a tetrameric protein consisting of two small and two large subunits. The small subunits have a catalytic function, while the large subunits regulate the enzyme activity. Cyperus esculentus (yellow nutsedge) is a perennial C4 plant grown from rhizomes and tubers. Previous studies on yellow nutsedge have mostly focused on the morphology and cultivation of tubers, their application in food, and biochemical analyses of the tubers. In this study, the gene encoding the ADPGlcPPase small subunit (CeAGPS) in yellow nutsedge was cloned and characterized. The full-length CeAGPS cDNA sequence contained an 81-bp 5'-untranslated region (UTR), a 188-bp 3'-UTR, and a 1539-bp open reading frame encoding 512-amino acid residues. The genomic sequence of CeAGPS comprises a nine exon-eight intron structure similar to the previously reported cotton and Arabidopsis thaliana AGPS genes. The deduced translation product of the CeAGPS gene contained a well-conserved catalytic domain and regulatory elements typical of plant AGPS. Reverse transcriptase polymerase chain reaction amplification of the target gene in various plant parts using gene-specific primers indicated that the expression of CeAGPS was most abundant in the tuber, and relatively lower in nutsedge roots.

Ecological investigation of three geophytes in the Deltaic Mediterranean coast of Egypt.

This study was conducted to investigate the ecological features of three geophytes namely Asparagus stipularis, Cyperus capitatus and Stipagrostis lanata which grow naturally in the Nile Delta coast of Egypt. C. capitatus and S. lanata are growing in non-saline sandy soils and can tolerate drought stress while, A. stipularis is growing in saline and non-saline sandy and calcareous clay soils and can tolerate drought and salt stress. Multivariate analysis of the vegetation of 100 sampled stands supporting growth of the three geophytic species in the study area led to the recognition of four vegetation groups namely, (A) Alhagi graecorum, (B) Cyperus capitatus, (C) Lycium schweinfurthii var. schweinfurthii-Asparagus stipularis and (D) Juncus acutus subsp. acutus. Vegetationally, the vegetation groups associated with the three species can be distinguished into two community types. The first one is psammophytic community comprising vegetation groups A and B that may represent the non-saline sand formations (flats, hummocks and dunes). The second one is halophytic community including vegetation groups C and D that may represent the saline sand flats and salt marsh habitat types, respectively. Sodium adsorption ratio, electrical conductivity, sodium cation, chlorides, silt and sand fractions, pH value, moisture content, bicarbonates and available phosphorus were the most effective soil factors that controlling the abundance and distribution of the plant communities associated with the investigated geophytes. This study showed the ecological features of the selected geophytes in terms of their habitats, associated plant communities and the most edaphic factors controlling their richness and distribution in the study area.