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Andrew A. Meharg - One of the best experts on this subject based on the ideXlab platform.
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Microbiome and ecotypic adaption of Holcus lanatus (L.) to extremes of its soil pH range, investigated through transcriptome sequencing.
Microbiome, 2018Co-Authors: Ellen Young, Andrew A. Meharg, Manus Carey, Caroline MehargAbstract:Background Plants can adapt to edaphic stress, such as nutrient deficiency, toxicity and biotic challenges, by controlled transcriptomic responses, including microbiome interactions. Traditionally studied in model plant species with controlled microbiota inoculation treatments, molecular plant-microbiome interactions can be functionally investigated via RNA-Seq. Complex, natural plant-microbiome studies are limited, typically focusing on microbial rRNA and omitting functional microbiome investigations, presenting a fundamental knowledge gap. Here, root and shoot meta-transcriptome analyses, in tandem with shoot elemental content and root staining, were employed to investigate transcriptome responses in the wild grass Holcus lanatus and its associated natural multi-species eukaryotic microbiome. A full factorial reciprocal soil transplant experiment was employed, using plant ecotypes from two widely contrasting natural habitats, acid bog and limestone quarry soil, to investigate naturally occurring, and ecologically meaningful, edaphically driven molecular plant-microbiome interactions.
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Microbiome and ecotypic adaption of Holcus lanatus (L.) to extremes of its soil pH range, investigated through transcriptome sequencing
BMC, 2018Co-Authors: Ellen Young, Andrew A. Meharg, Manus Carey, Caroline MehargAbstract:Abstract Background Plants can adapt to edaphic stress, such as nutrient deficiency, toxicity and biotic challenges, by controlled transcriptomic responses, including microbiome interactions. Traditionally studied in model plant species with controlled microbiota inoculation treatments, molecular plant-microbiome interactions can be functionally investigated via RNA-Seq. Complex, natural plant-microbiome studies are limited, typically focusing on microbial rRNA and omitting functional microbiome investigations, presenting a fundamental knowledge gap. Here, root and shoot meta-transcriptome analyses, in tandem with shoot elemental content and root staining, were employed to investigate transcriptome responses in the wild grass Holcus lanatus and its associated natural multi-species eukaryotic microbiome. A full factorial reciprocal soil transplant experiment was employed, using plant ecotypes from two widely contrasting natural habitats, acid bog and limestone quarry soil, to investigate naturally occurring, and ecologically meaningful, edaphically driven molecular plant-microbiome interactions. Results Arbuscular mycorrhizal (AM) and non-AM fungal colonization was detected in roots in both soils. Staining showed greater levels of non-AM fungi, and transcriptomics indicated a predominance of Ascomycota-annotated genes. Roots in acid bog soil were dominated by Phialocephala-annotated transcripts, a putative growth-promoting endophyte, potentially involved in N nutrition and ion homeostasis. Limestone roots in acid bog soil had greater expression of other Ascomycete genera and Oomycetes and lower expression of Phialocephala-annotated transcripts compared to acid ecotype roots, which corresponded with reduced induction of pathogen defense processes, particularly lignin biosynthesis in limestone ecotypes. Ascomycota dominated in shoots and limestone soil roots, but Phialocephala-annotated transcripts were insignificant, and no single Ascomycete genus dominated. Fusarium-annotated transcripts were the most common genus in shoots, with Colletotrichum and Rhizophagus (AM fungi) most numerous in limestone soil roots. The latter coincided with upregulation of plant genes involved in AM symbiosis initiation and AM-based P acquisition in an environment where P availability is low. Conclusions Meta-transcriptome analyses provided novel insights into H. lanatus transcriptome responses, associated eukaryotic microbiota functions and taxonomic community composition. Significant edaphic and plant ecotype effects were identified, demonstrating that meta-transcriptome-based functional analysis is a powerful tool for the study of natural plant-microbiome interactions
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Additional file 11: of Microbiome and ecotypic adaption of Holcus lanatus (L.) to extremes of its soil pH range, investigated through transcriptome sequencing
2018Co-Authors: Ellen Young, Andrew A. Meharg, Manus Carey, Caroline MehargAbstract:Selected fungal annotated transcript results, including those discussed in the text. The table contains the following information for selected microbial assigned transcripts that are expressed in Holcus lanatus roots, many of which discussed in the text: 1) Transcript ID; 2) Best BLAST match (taxonomic division, genus and gene description); 3) KOG annotations (KOG ID, KOG group, KOG class, KOG definition); 4) possible role; 5) relevant reference (citations for relevant references are contained in Additional file 7); 6) two columns to indicate whether the transcript was significantly upregulated in acid or limestone soil, acid or limestone ecotype; 7) The full DESeq2 result for each root pairwise comparison: these columns contain the log2foldchange and adjusted P value (FDR) for root pairwise comparisons. Pairwise comparisons are coded as follows: soil (A = acid bog soil, L = limestone quarry soil), plant ecotype (a = acid bog plant ecotype, l = limestone quarry plant ecotype): Root Aa-v-La = Acid bog soil acid ecotype versus Limestone soil acid ecotype, Root Al-v-Ll = Acid bog soil limestone ecotype versus Limestone soil limestone ecotype, Root Aa-v-Al = Acid bog soil acid ecotype versus Acid bog soil limestone ecotype, Root La-v-Ll = Limestone soil acid ecotype versus Limestone soil limestone ecotype. (XLSX 35 kb)
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trait directed de novo population transcriptome dissects genetic regulation of a balanced polymorphism in phosphorus nutrition arsenate tolerance in a wild grass Holcus lanatus
New Phytologist, 2014Co-Authors: Caroline Meharg, Bayezid Mahmud Khan, Gareth J. Norton, Claire Deacon, David W. Johnson, Richard Reinhardt, Bruno Huettel, Andrew A. MehargAbstract:Summary The aim of this study was to characterize the transcriptome of a balanced polymorphism, under the regulation of a single gene, for phosphate fertilizer responsiveness/arsenate tolerance in wild grass Holcus lanatus genotypes screened from the same habitat. De novo transcriptome sequencing, RNAseq (RNA sequencing) and single nucleotide polymorphism (SNP) calling were conducted on RNA extracted from H. lanatus. Roche 454 sequencing data were assembled into c. 22 000 isotigs, and paired-end Illumina reads for phosphorus-starved (P−) and phosphorus-treated (P+) genovars of tolerant (T) and nontolerant (N) phenotypes were mapped to this reference transcriptome. Heatmaps of the gene expression data showed strong clustering of each P+/P− treated genovar, as well as clustering by N/T phenotype. Statistical analysis identified 87 isotigs to be significantly differentially expressed between N and T phenotypes and 258 between P+ and P− treated plants. SNPs and transcript expression that systematically differed between N and T phenotypes had regulatory function, namely proteases, kinases and ribonuclear RNA-binding protein and transposable elements. A single gene for arsenate tolerance led to distinct phenotype transcriptomes and SNP profiles, with large differences in upstream post-translational and post-transcriptional regulatory genes rather than in genes directly involved in P nutrition transport and metabolism per se.
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Trait‐directed de novo population transcriptome dissects genetic regulation of a balanced polymorphism in phosphorus nutrition/arsenate tolerance in a wild grass, Holcus lanatus
The New phytologist, 2013Co-Authors: Caroline Meharg, Bayezid Mahmud Khan, Gareth J. Norton, Claire Deacon, David W. Johnson, Richard Reinhardt, Bruno Huettel, Andrew A. MehargAbstract:Summary The aim of this study was to characterize the transcriptome of a balanced polymorphism, under the regulation of a single gene, for phosphate fertilizer responsiveness/arsenate tolerance in wild grass Holcus lanatus genotypes screened from the same habitat. De novo transcriptome sequencing, RNAseq (RNA sequencing) and single nucleotide polymorphism (SNP) calling were conducted on RNA extracted from H. lanatus. Roche 454 sequencing data were assembled into c. 22 000 isotigs, and paired-end Illumina reads for phosphorus-starved (P−) and phosphorus-treated (P+) genovars of tolerant (T) and nontolerant (N) phenotypes were mapped to this reference transcriptome. Heatmaps of the gene expression data showed strong clustering of each P+/P− treated genovar, as well as clustering by N/T phenotype. Statistical analysis identified 87 isotigs to be significantly differentially expressed between N and T phenotypes and 258 between P+ and P− treated plants. SNPs and transcript expression that systematically differed between N and T phenotypes had regulatory function, namely proteases, kinases and ribonuclear RNA-binding protein and transposable elements. A single gene for arsenate tolerance led to distinct phenotype transcriptomes and SNP profiles, with large differences in upstream post-translational and post-transcriptional regulatory genes rather than in genes directly involved in P nutrition transport and metabolism per se.
Mark R. Macnair - One of the best experts on this subject based on the ideXlab platform.
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Arsenite efflux is not enhanced in the arsenate-tolerant phenotype of Holcus lanatus.
The New phytologist, 2009Co-Authors: B. Logoteta, Mark R. Macnair, Steve P. Mcgrath, Fang-jie ZhaoAbstract:P>Arsenate tolerance in Holcus lanatus is achieved mainly through suppressed arsenate uptake. We recently showed that plant roots can rapidly efflux arsenite to the external medium. Here, we tested whether arsenite efflux is a component of the adaptive arsenate tolerance in H. lanatus. Tolerant and nontolerant phenotypes were exposed to different arsenate concentrations with or without phosphate for 24 h, and arsenic (As) speciation was determined in nutrient solutions, roots and xylem sap. At the same arsenate exposure concentration, the nontolerant phenotype took up more arsenate and effluxed more arsenite than the tolerant phenotype. However, arsenite efflux was proportional to arsenate uptake and was not enhanced in the tolerant phenotype. Within 2-24 h, most (80-100%) of the arsenate taken up was effluxed to the medium as arsenite. About 86-95% of the As in the roots and majority of the As in xylem sap (c. 66%) was present as arsenite, and there were no significant differences between phenotypes. Arsenite efflux is not adaptively enhanced in the tolerant phenotype H. lanatus, but it could be a basal tolerance mechanism to greatly decrease cellular As burden in both phenotypes. Tolerant and nontolerant phenotypes had a similar capacity to reduce arsenate in roots. New Phytologist (2009) 183: 340-348doi: 10.1111/j.1469-8137.2009.02841.x.
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a polymorphism for phosphate uptake arsenate tolerance in Holcus lanatus l is there a correlation with edaphic or environmental factors
Heredity, 1996Co-Authors: Judy Naylor, Mark R. Macnair, Eirene Williams, Paul R. PoultonAbstract:Arsenate tolerance in Holcus lanatus L. is achieved by suppression of the high affinity phosphate uptake system. Tolerant plants are found at high frequency on noncontaminated soils. The selective agents acting to maintain this polymorphism are not understood. Work on the Park Grass Experiment and a nationwide survey revealed no significant correlation between the frequency of tolerant individuals and environmental or edaphic characteristics of the site. The results are interpreted in light of the low availability of phosphate in soil solution.
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A polymorphism for phosphate uptake/arsenate tolerance in Holcus lanatus L.: is there a correlation with edaphic or environmental factors?
Heredity, 1996Co-Authors: Judy Naylor, Mark R. Macnair, Eirene Williams, Paul R. PoultonAbstract:Arsenate tolerance in Holcus lanatus L. is achieved by suppression of the high affinity phosphate uptake system. Tolerant plants are found at high frequency on noncontaminated soils. The selective agents acting to maintain this polymorphism are not understood. Work on the Park Grass Experiment and a nationwide survey revealed no significant correlation between the frequency of tolerant individuals and environmental or edaphic characteristics of the site. The results are interpreted in light of the low availability of phosphate in soil solution.
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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
Plant and Soil, 1994Co-Authors: Andrew A. Meharg, J. Bailey, K. Breadmore, Mark R. MacnairAbstract: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.
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Polymorphism and physiology of arsenate tolerance in Holcus lanatus L. from an uncontaminated site
Plant and Soil, 1992Co-Authors: Andrew A. Meharg, Mark R. MacnairAbstract:The polymorphism of arsenate tolerance in a Holcus lanatus L. population from an uncontaminated soil was investigated and a high percentage of tolerant individuals (65%) was found in the population studied. Influx of arsenate was highly correlated to arsenate tolerance within the population, with the most tolerant individuals having the lowest rates of arsenate influx. Isotherms for the high affinity arsenate uptake systems were determined in six tolerant and six non-tolerant genotypes. Tolerant plants had the lowest rates of arsenate influx. This was achieved by adaptation of the Vmax of arsenate influx with the Vmax of the high affinity uptake system saturating at lower substrate concentrations in the tolerant plants. The polymorphism is discussed with relation to adaptation to the extreme environments to which the plants are subjected on mine-spoil soils.
Caroline Meharg - One of the best experts on this subject based on the ideXlab platform.
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Microbiome and ecotypic adaption of Holcus lanatus (L.) to extremes of its soil pH range, investigated through transcriptome sequencing.
Microbiome, 2018Co-Authors: Ellen Young, Andrew A. Meharg, Manus Carey, Caroline MehargAbstract:Background Plants can adapt to edaphic stress, such as nutrient deficiency, toxicity and biotic challenges, by controlled transcriptomic responses, including microbiome interactions. Traditionally studied in model plant species with controlled microbiota inoculation treatments, molecular plant-microbiome interactions can be functionally investigated via RNA-Seq. Complex, natural plant-microbiome studies are limited, typically focusing on microbial rRNA and omitting functional microbiome investigations, presenting a fundamental knowledge gap. Here, root and shoot meta-transcriptome analyses, in tandem with shoot elemental content and root staining, were employed to investigate transcriptome responses in the wild grass Holcus lanatus and its associated natural multi-species eukaryotic microbiome. A full factorial reciprocal soil transplant experiment was employed, using plant ecotypes from two widely contrasting natural habitats, acid bog and limestone quarry soil, to investigate naturally occurring, and ecologically meaningful, edaphically driven molecular plant-microbiome interactions.
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Additional file 1: of Microbiome and ecotypic adaption of Holcus lanatus (L.) to extremes of its soil pH range, investigated through transcriptome sequencing
2018Co-Authors: Ellen Young, Manus Carey, Andrew Meharg, Caroline MehargAbstract:Description of additional RNA-Seq data obtained from 3 hydroponically grown plants that were integrated into the Holcus lanatus metatranscriptome assembly. (DOCX 17 kb
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Additional file 11: of Microbiome and ecotypic adaption of Holcus lanatus (L.) to extremes of its soil pH range, investigated through transcriptome sequencing
2018Co-Authors: Ellen Young, Andrew A. Meharg, Manus Carey, Caroline MehargAbstract:Selected fungal annotated transcript results, including those discussed in the text. The table contains the following information for selected microbial assigned transcripts that are expressed in Holcus lanatus roots, many of which discussed in the text: 1) Transcript ID; 2) Best BLAST match (taxonomic division, genus and gene description); 3) KOG annotations (KOG ID, KOG group, KOG class, KOG definition); 4) possible role; 5) relevant reference (citations for relevant references are contained in Additional file 7); 6) two columns to indicate whether the transcript was significantly upregulated in acid or limestone soil, acid or limestone ecotype; 7) The full DESeq2 result for each root pairwise comparison: these columns contain the log2foldchange and adjusted P value (FDR) for root pairwise comparisons. Pairwise comparisons are coded as follows: soil (A = acid bog soil, L = limestone quarry soil), plant ecotype (a = acid bog plant ecotype, l = limestone quarry plant ecotype): Root Aa-v-La = Acid bog soil acid ecotype versus Limestone soil acid ecotype, Root Al-v-Ll = Acid bog soil limestone ecotype versus Limestone soil limestone ecotype, Root Aa-v-Al = Acid bog soil acid ecotype versus Acid bog soil limestone ecotype, Root La-v-Ll = Limestone soil acid ecotype versus Limestone soil limestone ecotype. (XLSX 35 kb)
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Microbiome and ecotypic adaption of Holcus lanatus (L.) to extremes of its soil pH range, investigated through transcriptome sequencing
BMC, 2018Co-Authors: Ellen Young, Andrew A. Meharg, Manus Carey, Caroline MehargAbstract:Abstract Background Plants can adapt to edaphic stress, such as nutrient deficiency, toxicity and biotic challenges, by controlled transcriptomic responses, including microbiome interactions. Traditionally studied in model plant species with controlled microbiota inoculation treatments, molecular plant-microbiome interactions can be functionally investigated via RNA-Seq. Complex, natural plant-microbiome studies are limited, typically focusing on microbial rRNA and omitting functional microbiome investigations, presenting a fundamental knowledge gap. Here, root and shoot meta-transcriptome analyses, in tandem with shoot elemental content and root staining, were employed to investigate transcriptome responses in the wild grass Holcus lanatus and its associated natural multi-species eukaryotic microbiome. A full factorial reciprocal soil transplant experiment was employed, using plant ecotypes from two widely contrasting natural habitats, acid bog and limestone quarry soil, to investigate naturally occurring, and ecologically meaningful, edaphically driven molecular plant-microbiome interactions. Results Arbuscular mycorrhizal (AM) and non-AM fungal colonization was detected in roots in both soils. Staining showed greater levels of non-AM fungi, and transcriptomics indicated a predominance of Ascomycota-annotated genes. Roots in acid bog soil were dominated by Phialocephala-annotated transcripts, a putative growth-promoting endophyte, potentially involved in N nutrition and ion homeostasis. Limestone roots in acid bog soil had greater expression of other Ascomycete genera and Oomycetes and lower expression of Phialocephala-annotated transcripts compared to acid ecotype roots, which corresponded with reduced induction of pathogen defense processes, particularly lignin biosynthesis in limestone ecotypes. Ascomycota dominated in shoots and limestone soil roots, but Phialocephala-annotated transcripts were insignificant, and no single Ascomycete genus dominated. Fusarium-annotated transcripts were the most common genus in shoots, with Colletotrichum and Rhizophagus (AM fungi) most numerous in limestone soil roots. The latter coincided with upregulation of plant genes involved in AM symbiosis initiation and AM-based P acquisition in an environment where P availability is low. Conclusions Meta-transcriptome analyses provided novel insights into H. lanatus transcriptome responses, associated eukaryotic microbiota functions and taxonomic community composition. Significant edaphic and plant ecotype effects were identified, demonstrating that meta-transcriptome-based functional analysis is a powerful tool for the study of natural plant-microbiome interactions
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trait directed de novo population transcriptome dissects genetic regulation of a balanced polymorphism in phosphorus nutrition arsenate tolerance in a wild grass Holcus lanatus
New Phytologist, 2014Co-Authors: Caroline Meharg, Bayezid Mahmud Khan, Gareth J. Norton, Claire Deacon, David W. Johnson, Richard Reinhardt, Bruno Huettel, Andrew A. MehargAbstract:Summary The aim of this study was to characterize the transcriptome of a balanced polymorphism, under the regulation of a single gene, for phosphate fertilizer responsiveness/arsenate tolerance in wild grass Holcus lanatus genotypes screened from the same habitat. De novo transcriptome sequencing, RNAseq (RNA sequencing) and single nucleotide polymorphism (SNP) calling were conducted on RNA extracted from H. lanatus. Roche 454 sequencing data were assembled into c. 22 000 isotigs, and paired-end Illumina reads for phosphorus-starved (P−) and phosphorus-treated (P+) genovars of tolerant (T) and nontolerant (N) phenotypes were mapped to this reference transcriptome. Heatmaps of the gene expression data showed strong clustering of each P+/P− treated genovar, as well as clustering by N/T phenotype. Statistical analysis identified 87 isotigs to be significantly differentially expressed between N and T phenotypes and 258 between P+ and P− treated plants. SNPs and transcript expression that systematically differed between N and T phenotypes had regulatory function, namely proteases, kinases and ribonuclear RNA-binding protein and transposable elements. A single gene for arsenate tolerance led to distinct phenotype transcriptomes and SNP profiles, with large differences in upstream post-translational and post-transcriptional regulatory genes rather than in genes directly involved in P nutrition transport and metabolism per se.
Paul R. Poulton - One of the best experts on this subject based on the ideXlab platform.
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a polymorphism for phosphate uptake arsenate tolerance in Holcus lanatus l is there a correlation with edaphic or environmental factors
Heredity, 1996Co-Authors: Judy Naylor, Mark R. Macnair, Eirene Williams, Paul R. PoultonAbstract:Arsenate tolerance in Holcus lanatus L. is achieved by suppression of the high affinity phosphate uptake system. Tolerant plants are found at high frequency on noncontaminated soils. The selective agents acting to maintain this polymorphism are not understood. Work on the Park Grass Experiment and a nationwide survey revealed no significant correlation between the frequency of tolerant individuals and environmental or edaphic characteristics of the site. The results are interpreted in light of the low availability of phosphate in soil solution.
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A polymorphism for phosphate uptake/arsenate tolerance in Holcus lanatus L.: is there a correlation with edaphic or environmental factors?
Heredity, 1996Co-Authors: Judy Naylor, Mark R. Macnair, Eirene Williams, Paul R. PoultonAbstract:Arsenate tolerance in Holcus lanatus L. is achieved by suppression of the high affinity phosphate uptake system. Tolerant plants are found at high frequency on noncontaminated soils. The selective agents acting to maintain this polymorphism are not understood. Work on the Park Grass Experiment and a nationwide survey revealed no significant correlation between the frequency of tolerant individuals and environmental or edaphic characteristics of the site. The results are interpreted in light of the low availability of phosphate in soil solution.
T. N. Barry - One of the best experts on this subject based on the ideXlab platform.
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Comparative studies of herbage intake and performance of lambs grazing Yorkshire fog (Holcus lanatus) and tall fescue (Festuca arundinacea) pastures under rotational management in summer
New Zealand Journal of Agricultural Research, 1997Co-Authors: F. Y. Liu, John G. Hodgson, T. N. BarryAbstract:Abstract Grazing experiments were conducted on Yorkshire fog (Holcus lanatus cv. Massey Basyri)/white clover (Trifolium repens cv. Grasslands Tahora) and tall fescue (Festuca arundinacea cv. Grasslands Roa)/white clover pastures in late spring‐summer (Nov‐Jan, Experiment 1) and summer‐early autumn (Jan‐Mar, Experiment 2) to assess behaviour and performance of lambs and to evaluate the effects of low concentrations of condensed tannins (CT) in the grasses on lamb performance. In each experiment, 48 lambs were allocated to three groups, balanced for previous grazing experience and sex, in sets of 16. One group was slaughtered at the start of the experiment to measure carcass weight; the other two groups of lambs rotationally grazed paddocks within each pasture. Half of the lambs within each pasture were drenched with 10 g polyethylene glycol (PEG; mol. weight 3350) twice daily at 0830 and 1630 hrs and the remaining lambs were drenched with water as a control. There were similar sward surface height, herbage...
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Comparative studies of herbage intake and performance of lambs grazing Yorkshire fog (Holcus lanatus) and perennial ryegrass (Lolium perenne) pastures in winter
New Zealand Journal of Agricultural Research, 1997Co-Authors: F. Y. Liu, John G. Hodgson, T. N. BarryAbstract:Abstract A comparative trial was carried out to assess the grazing behaviour, and performance of lambs grazing Yorkshire fog (Holcus lanatus cv. Massey Basyn)/white clover (Trifolium repens cv. Grasslands Tahora) and perennial ryegrass (Lolium perenne cv. Grasslands Nui)/white clover pastures and to evaluate the effects of low concentrations of condensed tannins (CT) in the grasses on body and wool growth under continuous stocking management in winter. Thirty‐six spring‐born female lambs of mean initial live weight 29 ± 2.3 kg were allocated to balanced groups in sets of six, with three replicates of the two pasture treatments. Individual paddocks were grazed continuously for 7 weeks from 30 May to 15 July. Half of the lambs were drenched with 10 g polyethylene glycol (PEG: molecular weight 4000) twice daily at 0830 and 1700 hrs and the remaining lambs were drenched with water as a control. Yorkshire fog swards had greater herbage mass and bulk density, lower proportions of live leaf and white clover, and...
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Variation in condensed tannin concentration of a temperate grass (Holcus lanatus) in relation to season and reproductive development.
Journal of chemical ecology, 1995Co-Authors: G. R. Iason, J. Hodgson, T. N. BarryAbstract:Holcus lanatus, a temperate grass, was found to contain low but measurable concentrations of condensed tannins (CT), according to the vanillin-HCl and the butanol-HCl methods. The variation in CT concentrations between different types of tissue including leaf age and reproductive versus nonreproductive tissue was examined. There was no evidence that floral tissue contained more CT than nonreproductive tissue. A sequential extraction and analysis procedure showed a decreasing proportion of free-unbound CT and greater preponderance of protein-bound and fiber-bound CT with increasing leaf age and in dead matter. Samples collected from an agricultural pasture on two sampling dates, January 24 and March 5, 1993, showed short-term temporal variation in free-unbound CT.