Responses of Artemisia frigida Willd. (Compositae) and Leymus chinensis (Trin.) Tzvel. (Poaceae) to sheep saliva

Although studies show that grazing and browsing by herbivores have marked effects on host plants, the mechanisms remain unclear. The objective of this study is to determine the effects of sheep saliva on host plant growth. Sheep saliva was manually applied to clipped plants of two different life forms, a semi-shrub, Artemisia frigida Willd., and a herbaceous species, Leymus chinensis (Trin.) Tzevel. The results showed that sheep saliva significantly enhanced aboveground net primary productivity (ANPP) and the ratio of ANPP to belowground net primary productivity (BNPP) for both species. This indicated that sheep saliva promotes aboveground compensatory growth and allocation of photosynthate to aboveground for both plant species. Sheep saliva stimulated only tillering of L. chinensis. Regardless of saliva application, clipping significantly decreased BNPP and plant height, but significantly increased the number of branches or tillers for both plant species. The relative growth rates (RGRs) on both species were significantly greater after clipping with saliva compared with control and clipping without saliva treatments. In addition, RGR of the herbaceous species L. chinensis was faster than that of the semi-shrub A. frigida after application of saliva. (c) 2006 Elsevier Ltd. All rights reserved.

Genome constitutions of Hystrix patula, H-duthiei ssp duthiei and H-duthiei ssp longearistata (Poaceae : Triticeae) revealed by meiotic pairing behavior and genomic in-situ hybridization

Genomic constitutions of three taxa of Hystrix Moench, H. patula, H. duthiei ssp. duthiei and H. duthiei ssp. longearistata, were examined by meiotic pairing behavior and genomic in-situ hybridization. Meiotic pairing in hybrids of H. patula x Pseudoroegneria spicata (St), H. patula x Elymus wawawaiensis (StH), H. patula x H. duthiei ssp. longearistata, H. patula x Psathyrostachys huashanica (Ns(h)), H. duthiei ssp. duthiei x Psa. huashanica, H. duthiei ssp. longearistata x Psa. huashanica, Leymus multicaulis (NsXm) x H. duthiei ssp. longearistata averaged 6.53, 12.83, 1.32, 0.29, 5.18, 5.11 and 10.47 bivalents per cell, respectively. The results indicate that H. patula has the StH genome and H. duthiei ssp. duthiei and H. duthiei ssp. longearistata have the NsXm genome. Results of genomic in-situ hybridization analysis strongly supported the chromosome pairing data; therefore it is concluded that the type species of Hystrix, H. patula, should be included in Elymus, and that H. duthiei ssp. duthiei and H. duthiei ssp. longearistata should be transferred to Leymus.

Tripogon debilis (Poaceae), a new species from western China

A new species of Tripogon from western China (Sichuan Province), T. debilis L. B. Cai, is described and illustrated. This species is similar to both T. chinensis (Franchet) Hackel and T sichuanicus S. M. Phillips & S. L. Chen, but distinguished from these two species by its pendent pi spikes, relatively tong glumes and lemma awns, denticulate upper glumes, and its paleas strikingly shorter than the lemmas.

Notes on grasses (Poaceae) for the Flora of China, VI. New combinations in Stipeae and Anthoxantham

When Oryzopsis is confined to the type species, Chinese species are placed in Achnatherum and Piptatherum. This necessitates the following new combinations: Piptatherum grandispiculum, Piptatherum aequiglume var. ligulatum, Piptatherum tibeticum var. psilolepis.. Piptatherum. munroi var. parviflorum, Achnatherum henryi. and Achnatherum henryi var. acutum. Achnatherum henryi is lectotypified. The new name Piptatherum kuoi replaces the illegitimate name Piptatherum obtusum, and this species is lectotypified. Hierochloe potaninii is transferred to Anthoxanthum as A. potaninii, as Hierochloe is regarded as a synonym of Anthoxanthum. All the grass taxa (Poaceae) listed are endemic to China.

Two new species of Leymus (Poaceae : Triticeae) from Qinghai, China

Two new species of Leymus, L. pendulus and L. obvipodus, are described and illustrated. These two species are endemic to Qinghai province, China, occurring at the margins of woodlands, wastelands, mountain valleys, and the bases of walls, at 2280-2400 m elevation. Leymus pendulus is unusual in its lax, long, pendent spikes. It is closely related to L. flexus, but differs from that species by pendent spikes, longer rachis internodes, and shorter glumes and lemmas. Leymus obvipodus is unique in the genus in having all spikelets pedicellate. It resembles both L. divaricatus (Drobow) Tzvelev and L. aristiglumus L. B. Cai but differs from the former by lanceolate glumes with 1 to 3 nerves, longer spike-like panicles, taller culms, and lanceolate lemmas with 5 obscure nerves and pubescent margins, and from the latter by lax, longer spike-like panicles, pedicellate spikelets with 4 to 8 florets, narrower glumes, and longer, lustrous lemmas.

Características reproductivas de Setaria lachnea (Nees) Kunth (Poaceae, Paniceae)

p.59-66

New species of Festuca L. section Festuca (Poaceae) in the Iberian Peninsula

Se describe una nueva especie diploide de Festuca L., F vettonica, perteneciente a la serie Intravaginales Hackel (sección Festuca) en el macizo de La Serrota (Sistema Central, España). Se aportan caracteres morfológicos, anatómicos y citológicos de este taxon.

Universal primers for the amplification of chloroplast microsatellites in grasses (Poaceae)

Attempts to design truly universal primers to amplify chloroplast microsatellites have met with limited success due to nonconservation of repeat loci across widely divergent taxa. We have used the complete chloroplast genome sequences of rice, maize and wheat to design five pairs of primers that amplify homologous mononucleotide repeats across the Poaceae (grasses). Sequencing confirmed conservation of repeat motifs across subfamilies and a preliminary study in Anthoxanthum odoratum revealed polymorphism at two loci with a haplotype diversity value of 0.495. These primers provide a valuable tool to study cytoplasmic diversity in this extensively studied and economically important range of taxa.

Biomass allocation, phosphorus nutrition and vesicular-arbuscular mycorrhizal infection in clones of Yorkshire Fog, Holcus lanatus L. (Poaceae) that differ in their phosphate uptake kinetics and tolerance to arsenate

Biomass and phosphorus allocation were determined in arsenate tolerant and non-tolerant clones of the grass Holcus lanatus L. in both solution culture and in soil. Arsenate is a phosphate analogue and is taken up by the phosphate uptake system. Tolerance to arsenate in this grass is achieved by suppression of arsenate (and phosphate) influx. When clones differing in their arsenate tolerance were grown in solution culture with a range of phosphate levels, a tolerant clone did not fare as well as a non-tolerant at low levels of phosphate nutrition in that it had reduced shoot biomass production, increased biomass allocation to the roots and lower shoot phosphorus concentration. At a higher level of phosphate nutrition there was little or no difference in these parameters, suggesting that differences at lower levels of phosphate nutrition were due solely to differences in the rates of phosphate accumulation. In experiments in sterile soil (potting compost) the situation was more complicated with tolerant plants having lower growth rates but higher phosphorus concentrations. The gene for arsenate tolerance is polymorphic in arsenate uncontaminated populations. When phosphorus concentration of tolerant phenotypes was determined in one such population, again tolerants had a higher phosphorus status than non-tolerants. Tolerants also had higher rates of vesicular-arbuscular mycorrhizal (VAM) infection. The ecological implications of these results are that it appears that suppression of the high affinity uptake system, is at least in part, compensated by increased mycorrhizal infection. © 1994 Kluwer Academic Publishers.

Pollen Production in the Poaceae Family.

Total pollen production per inflorescence was studied in the most important species of the Poaceae family in the city of Córdoba in order to further our knowledge of the partial contribution of each species of this family to the total amount of pollen released into the atmosphere. The contribution of grasses in a given area was estimated by counting the number of inflorescences in an area of one square meter. Four different representative areas of the city were selected. The number of pollen grains per anther and flowers per inflorescence was also estimated in order to obtain total pollen production per inflorescence. Pollen production per inflorescence ranged from 14,500 to more than 22,000,000 pollen grains, the amount being clearly higher in the perennial species. Pollen production per square meter was higher in the mountains near the city and lower in areas of abandoned crops. Only a few species are responsible for the majority of pollen produced. A phenological study is necessary in order to determine the temporal distribution of this pollen production and subsequent shedding.

Long-term and Short-term Forecast Models for Poaceae (Grass) Pollen in Poznan, Poland, Constructed Using Regression Analysis

Airborne concentrations of Poaceae pollen have been monitored in Poznań for more than ten years and the length of the dataset is now considered sufficient for statistical analysis. The objective of this paper is to produce long-range forecasts that predict certain characteristics of the grass pollen season (such as the start, peak and end dates of the grass pollen season) as well as short-term forecasts that predict daily variations in grass pollen counts for the next day or next few days throughout the main grass pollen season. The method of forecasting was regression analysis. Correlation analysis was used to examine the relationship between grass pollen counts and the factors that affect its production, release and dispersal. The models were constructed with data from 1994-2004 and tested on data from 2005 and 2006. The forecast models predicted the start of the grass pollen season to within 2 days and achieved 61% and 70% accuracy on a scale of 1-4 when forecasting variations in daily grass pollen counts in 2005 and 2006 respectively. This study has emphasised how important the weather during the few weeks or months preceding pollination is to grass pollen production, and draws attention to the importance of considering large-scale patterns of climate variability (indices of the North Atlantic Oscillation) when constructing forecast models for allergenic pollen.

Relative Efficiencies of the Burkard 7-Day, Rotorod and Burkard Personal Samplers for Poaceae and Urticaceae Pollen under Field Conditions

Introduction: In aerobiological studies it is often necessary to compare concentration data recorded with different models of sampling instrument. Sampler efficiency typically varies from device to device, and depends on the target aerosol and local atmospheric conditions. To account for these differences inter-sampler correction factors may be applied, however for many pollen samplers and pollen taxa such correction factors do not exist and cannot be derived from existing published work. Materials and methods: In this study the relative efficiencies of the Burkard 7-Day Recording Volumetric Spore Trap, the Sampling Technologies Rotorod Model 20 and the Burkard Personal Volumetric Air Sampler were evaluated for Urticaceae and Poaceae pollen under field conditions, and the influence of wind speed and relative humidity on these efficiency relationships was assessed. Data for the two pollen taxa were collected during 2010 and 2011-12 respectively. Results: The three devices were found to record significantly different concentrations for both pollen taxa, with the exception of the 7-Day and Rotorod samplers for Poaceae pollen. Under the range of conditions present during the study wind speed was found to only have a significant impact on inter-sampler relationships involving the vertically orientated Burkard Personal sampler, whilst no interaction between relative efficiency and relative humidity was observed. Conclusions: Data collected with the three models of sampler should only be compared once the appropriate correction has been made, with wind speed taken into account where appropriate.

Comparison of Poaceae Pollen Counts Recorded at Sites in Portugal, Spain and the UK

The main aim of this study was to analyse the temporal and spatial variations in grass (Poaceae) pollen counts (2005–2011) recorded in Évora (Portugal), Badajoz (Spain) and Worcester (UK). Weekly average data were examined using nonparametric statistics to compare differences between places. On average, Évora recorded the earliest start dates of the Poaceae pollen seasons and Worcester the latest. The intensity of the Poaceae pollen season varied between sites, with Worcester usually recording the least and Évora the most grass pollen in a season. Mean durations of grass pollen seasons were 77 days in Évora, 78 days in Badajoz and 59 days in Worcester. Overall, longer Poaceae pollen seasons coincided with earlier pollen season start dates. Weekly pollen data, from March to September, from the three pollen-monitoring stations studied were compared. The best fit and most statistically significant correlations were obtained by moving Worcester data backward by 4 weeks (Évora, r = 0.810, p < 0.001) and 5 weeks (Badajoz,r = 0.849, p < 0.001). Weekly data from Worcester therefore followed a similar pattern to that of Badajoz and Évora but at a distance of more than 1,500 km and 4–5 weeks later. The sum of pollen recorded in a season was compared with monthly rainfall between January and May. The strongest positive relationship between season intensity and rainfall was between the annual sum of Poaceae pollen recorded in the season at Badajoz and Évora and total rainfall during January and February. Winter rainfall noticeably affects the intensity of Poaceae pollen seasons in Mediterranean areas, but this was not as important in Worcester.

Genome dynamics explain the evolution of flowering time CCT domain gene families in the Poaceae

Numerous CCT domain genes are known to control flowering in plants. They belong to the CONSTANS-like (COL) and PREUDORESPONSE REGULATOR (PRR) gene families, which in addition to a CCT domain possess B-box or response-regulator domains, respectively. Ghd7 is the most recently identified COL gene to have a proven role in the control of flowering time in the Poaceae. However, as it lacks B-box domains, its inclusion within the COL gene family, technically, is incorrect. Here, we show Ghd7 belongs to a larger family of previously uncharacterized Poaceae genes which possess just a single CCT domain, termed here CCT MOTIF FAMILY (CMF) genes. We molecularly describe the CMF (and related COL and PRR) gene families in four sequenced Poaceae species, as well as in the draft genome assembly of barley (Hordeum vulgare). Genetic mapping of the ten barley CMF genes identified, as well as twelve previously unmapped HvCOL and HvPRR genes, finds the majority map to colinear positions relative to their Poaceae orthologues. Combined inter-/intra-species comparative and phylogenetic analysis of CMF, COL and PRR gene families indicates they evolved prior to the monocot/dicot divergence ~200 mya, with Poaceae CMF evolution described as the interplay between whole genome duplication in the ancestral cereal, and subsequent clade-specific mutation, deletion and duplication events. Given the proven role of CMF genes in the modulation of cereals flowering, the molecular, phylogenetic and comparative analysis of the Poaceae CMF, COL and PRR gene families presented here provides the foundation from which functional investigation can be undertaken.