Perennial Grass

Switchgrass, Panicum virgatum, is a perennial grass native to the USA and Canada with an array of ploidy levels and ecotypes. In this study, genetic variation in the nuclear gene encoding plastid acetyl-CoA carboxylase from six switchgrass cultivars was investigated with the goal of defining relationships among these populations using DNA sequence comparisons. Four polymorphic sites were found in exons and 18 polymorphic sites plus four indels were found in introns within a 1828-nucleotide sequence alignment (696 nucleotides in exons and 1132 nucleotides in introns) of 27 genes. The homoeologous genomes of tetraploid and octaploid switchgrass are very closely related to each other, and among and between lowland and upland switchgrass ecotypes. Based on the molecular clock determined earlier for the Triticeae tribe, the genome divergence time and the time of the polyploidization events which established various contemporary switchgrass lineages was estimated to be less than 2 million...

Erratum to: Irrig Sci (2010) 28:497–509 DOI 10.1007/s00271-010-0210-zFollowing publication of the paper, the authors have detected a calculation error in the calibration of the FAO56 Penman–Monteith method used for estimating greenhouse reference evapotranspiration (ETo). There is an error in the value of aerodynamic resistance (ra) presented in the paper.While a standard value of 150 s m−1 was reported for the aerodynamic resistance (ra) in the paper, we found subsequently that the correct value of ra, that provides the best agreement between estimated and measured daily greenhouse ETo values, as determined by minimizing the root mean square error (RMSE) with the SOLVER procedure (Microsoft® Excel 2002), is 295 s m−1. Measured ETo data from 1993 and 1994 (without whitening), and from 2000 and 2001 (with whitening) were used for model calibration. With a fixed ra value of 295 s m−1, the FAO56 Penman–Monteith method was validated using measured ETo values from 1995, 1997 and 1999 (witho

We used univariate and multivariate techniques to evaluate vegetation-environment relationships for plant func- tional groups on a tallgrass prairie site in northern Oklahoma, USA burned seasonally and grazed by bison (Bison bison L.). The objective of the study was to identify important environmental variables associated with variation in residual aboveground standing crop (phytomass) and abundance of plant functional groups. Phytomass

Fifteen herbaceous perennial grass and herb species were planted into experimental green roofs in spring 2001. The species differed widely in their origins, heights, flowering times, life spans and growth forms but all were typical of dry and nutrient-stressed habitats. Three individuals of each species of a standardised size were randomly assigned to a planting grid at 20 cm apart in each experimental replicate plot at substrate depth of either 100 or 200 mm. Each treatment was replicated three times. During each growing season, the mean height and spread of each individual was recorded, together with flowering performance and % vegetation cover. In addition the numbers and % covers of all spontaneous colonised species were recorded. Greatest survival, diversity, size and flowering performance of planted species occurred at 200 mm depth. Bare ground and moss cover was greatest at 100 mm, as was diversity of colonising species. Differences between the early years and the final years of the experiment indicate the need for long-term monitoring of green roofs in addition to short-term experiments.

We investigated C management index (CMI; an indicator of sustainability of a management system and is based on total and labile C) and soil aggregation in medium-textured soils (silt loam and silty clay loam) under different cropping systems as follows: maize-wheat (M-W), rice-wheat (R-W), soybean-wheat (S-W), Guinea grass, and Setaria grass. Field experiments were 6–32 years long and were located in the wet-temperate zone of northwest Himalayas. The plant nutrients were applied through chemical fertilizers (urea, superphosphate, and muriate of potash) with or without organic materials (FYM, wheat straw, and Lantana spp.). The content of total C (CT), labile C (CL), CMI, mean weight diameter (MWD), and aggregate porosity varied significantly under different cropping systems. The range was 1.59 (R-W)–4.29% (Setaria) for CT, 1.23 (R-W)–3.89 mg/kg (Guinea grass) for CL, 52.09 (R-W)–129.77 (Guinea grass) for CMI, 0.90 (R-W)–5.09 (Guinea grass) for MWD, and 41.5 (R-W)–56.8% (S-W) for aggregate porosity. Aggregate porosity was highest (56.8%) under S-W, followed by grasses (50.1–51.2%), and M/R-W (41.5–50.0%). As per these data, (a) continuous use of N alone as urea lowered soil sustainability over control (no fertilizers); (b) use of NPK at recommended rates improved soil productivity over control; (c) the NPK + organic amendments further improved soil sustainability; and (d) the sustainability under different cropping systems followed the order: perennial grasses > soybean-wheat > maize-wheat > rice-wheat.

Our study examined the influence of elevated ozone levels on the growth and mycorrhizal colonization of two populations of Elymus glaucus L. (blue wildrye). We hypothesized that ozone would reduce carbon availability to the plants, particularly below ground, and would affect mycorrhizal colonization. Because of the wide geographic range of E. glaucus, two populations of plants were selected from areas

Ten novel polymorphic microsatellites (seven with perfect motifs) were isolated from vairone species (Telestes souffia and Telestes muticellus), which are endangered European cyprinid species. Together with 11 previously published cyprinid-specific loci, five multiplex sets were optimized, allowing the genotyping of 21 polymorphic loci. The level of genetic diversity was assessed in 97 individuals from the two species T. souffia and T. muticellus. We also successfully applied the 21 microsatellites to nine related species. These primers will thus be useful in assessing population structure of the vairone and other cyprinid species, with application for conservation issues and phylogeographical approaches.