scholarly journals   Distribution of recently fixed photosynthate in a switchgrass plant-soil system

2012 ◽  
Vol 58 (No. 6) ◽  
pp. 249-255 ◽  
Author(s):  
D.R. Chaudhary ◽  
J. Saxena ◽  
N. Lorenz ◽  
R.P. Dick
Keyword(s):  
Panicum Virgatum ◽  
Rhizosphere Soil ◽  
Microbial Biomass Carbon ◽  
Bulk Soil ◽  
Energy Crop ◽  
Marginal Lands ◽  
Soil System ◽  
Plant Soil ◽  
Panicum Virgatum L ◽  
Maintenance Requirements

The use of switchgrass (Panicum virgatum L.) as an energy crop has gained great importance in past two decades due to its high biomass yields on marginal lands with low agricultural inputs and low maintenance requirements. Information on the allocation of photosynthetically fixed C in the switchgrass-soil system is important to understand the C flow and to quantify the sequestration of C in soils. The allocation of <sup>13</sup>C labeled photosynthates in shoot, root, soil, and in microbial biomass carbon (MBC) of rhizosphere and bulk soil of 45 days old, greenhouse grown-switchgrass was examined during 20 days <sup>13</sup>C-CO<sub>2</sub> pulse labeling period. The total <sup>13</sup>C recovered in the plant-soil system varied from 79% after 1 day to 42% after 20 days of labeling. After labeling, 54%, 40%, and 6% excess <sup>13</sup>C resided in shoot, root and soil, respectively on day 1; 27%, 61% and 11%, respectively on day 5 and 20%, 63% and 17%, respectively day 20 after labeling. The maximum incorporation of <sup>13</sup>C from roots into the MB of rhizosphere soil occurred within the first 24 h of labeling. The excess <sup>13</sup>C values of rhizosphere soil and rhizosphere MBC were significantly higher than excess <sup>13</sup>C values of bulk soil and the bulk soil MBC, respectively. The proportion of excess <sup>13</sup>C in soil as MBC declined from 92 to 15% in rhizosphere soil and from 79 to 18% in bulk soil, for 1 day and 20 days after labeling, respectively. The present study showed the effectiveness of <sup>13</sup>C labeling to examine the fate of recently photosynthesized C in soil-plant (switchgrass) system and dynamics of MBC. &nbsp;

scholarly journals Protist diversity and community complexity in the rhizosphere of switchgrass are dynamic as plants develop

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Javier A. Ceja-Navarro ◽  
Yuan Wang ◽  
Daliang Ning ◽  
Abelardo Arellano ◽  
Leila Ramanculova ◽  
...  
Keyword(s):  
Community Composition ◽  
Community Assembly ◽  
Panicum Virgatum ◽  
Large Scale ◽  
Rhizosphere Soil ◽  
Bacterial Community Composition ◽  
Temporal Variations ◽  
Bulk Soil ◽  
Growth Stages ◽  
Soil System

Abstract Background Despite their widespread distribution and ecological importance, protists remain one of the least understood components of the soil and rhizosphere microbiome. Knowledge of the roles that protists play in stimulating organic matter decomposition and shaping microbiome dynamics continues to grow, but there remains a need to understand the extent to which biological and environmental factors mediate protist community assembly and dynamics. We hypothesize that protists communities are filtered by the influence of plants on their rhizosphere biological and physicochemical environment, resulting in patterns of protist diversity and composition that mirror previously observed diversity and successional dynamics in rhizosphere bacterial communities. Results We analyzed protist communities associated with the rhizosphere and bulk soil of switchgrass (SG) plants (Panicum virgatum) at different phenological stages, grown in two marginal soils as part of a large-scale field experiment. Our results reveal that the diversity of protists is lower in rhizosphere than bulk soils, and that temporal variations depend on soil properties but are less pronounced in rhizosphere soil. Patterns of significantly prevalent protists groups in the rhizosphere suggest that most protists play varied ecological roles across plant growth stages and that some plant pathogenic protists and protists with omnivorous diets reoccur over time in the rhizosphere. We found that protist co-occurrence network dynamics are more complex in the rhizosphere compared to bulk soil. A phylogenetic bin-based null model analysis showed that protists’ community assembly in our study sites is mainly controlled by homogenous selection and dispersal limitation, with stronger selection in rhizosphere than bulk soil as SG grew and senesced. Conclusions We demonstrate that environmental filtering is a dominant determinant of overall protist community properties and that at the rhizosphere level, plant control on the physical and biological environment is a critical driver of protist community composition and dynamics. Since protists are key contributors to plant nutrient availability and bacterial community composition and abundance, mapping and understanding their patterns in rhizosphere soil is foundational to understanding the ecology of the root-microbe-soil system.

scholarly journals Changes in nitrogen pools in the maize-soil system after urea or straw application to a typical intensive agricultural soil: A 15N tracer study

2020 ◽  
Author(s):  
Jie Zhang ◽  
Ping He ◽  
Dan Wei ◽  
Liang Jin ◽  
Lijuan Zhang ◽  
...  
Keyword(s):  
Rhizosphere Soil ◽  
Bulk Soil ◽  
15N Tracer ◽  
Organic N ◽  
Microbial Biomass N ◽  
Soil System ◽  
Total N ◽  
Available N ◽  
Leaf Stage ◽  
Exogenous Substrate

AbstractA 15N maize pot experiment was conducted to compare the N value of fertilizer alone and fertilizer combined with straw at an equivalent N rate. The four treatments were control (CK), 15N-urea, 15N-urea plus straw, and 15N-straw plus urea. Soil N pools, maize N and their 15N abundance were determined during maize growth. At maturity 26.0% of straw N was assimilated by maize in the urea plus straw treatment. From the eighth leaf stage to maturity, urea plus straw had a significantly (P < 0.05) higher concentration and percentage of exogenous substrate N present as soil total N (TN), particulate organic N (PON), and mineral associated total N (MTN) in bulk and rhizosphere soils than the urea-only treatment. From silking to maturity in the urea plus straw treatment, rhizosphere soil significantly (P < 0.05) increased the percentage of exogenous substrate N present as inorganic N (Inorg-N) and MTN, and significantly (P < 0.05) decreased that present as PON and microbial biomass N (MBN) compared with the bulk soil. From the eighth leaf stage to maturity, rhizosphere soil significantly (P < 0.05) increased the percentage of straw N present as Inorg-N and MTN except for MTN at the silking stage, and significantly decreased (P < 0.05) that present as PON compared with the bulk soil. Overall, straw was an available N source to the crop, and the increase in straw N availability needs to be considered from the interaction of fertilization practices and the crop rhizosphere.

scholarly journals Microbial Profiles of Rhizosphere and Bulk Soil Microbial Communities of Biofuel Crops Switchgrass (Panicum virgatumL.) and Jatropha (Jatropha curcasL.)

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Doongar R. Chaudhary ◽  
Jyotisna Saxena ◽  
Nicola Lorenz ◽  
Linda K. Dick ◽  
Richard P. Dick
Keyword(s):  
Microbial Communities ◽  
Panicum Virgatum ◽  
Rhizosphere Soil ◽  
Phospholipid Fatty Acid ◽  
Root Exudation ◽  
Soil Microbial Communities ◽  
Environmental Benefits ◽  
Bulk Soil ◽  
Gram Negative ◽  
Biofuel Crops

The production of biofuels from the low-input energy crops, switchgrass (Panicum virgatumL.) and jatropha (Jatropha curcasL.), is a sustainable approach that can provide more usable energy and environmental benefits than food-based biofuels. Plant rhizosphere affects the microbial community structure due to variations in root exudation rates and residue chemistry. The objective of this investigation was to determine the profiles of microbial communities associated with rhizosphere and bulk soils of switchgrass or jatropha using phospholipid fatty acid (PLFA) analysis and length heterogeneity PCR (LH-PCR). Switchgrass soil contained a significantly (P<0.05) higher abundance of Gram-positive (i14:0, i15:0, a15:0), Gram-negative (16:1ω5c, 16:1ω7c, 18:1ω5c), and saturated (14:0, 15:0) PLFAs compared to jatropha soil, whereas jatropha had a higher abundance of fungal (18:2ω6, 9c), 18:1ω9c, 20:1ω9c, and 18:0 PLFAs compared to switchgrass soil. Irrespective of plant type, rhizosphere soil contained a significantly (P<0.05) higher abundance of saturated PLFAs (16:0, 18:0, 20:0), actinomycetes (10Me17:0), and fungal (18:2ω6, 9c) PLFAs compared to bulk soil; whereas bulk soil had higher abundance of saturated (14:0), Gram-negative (16:1ω9c, 16:1ω5c, 16:1ω7c), and 18:1ω9c PLFAs compared to rhizosphere soil. Multivariate principle component analysis of PLFAs and LH-PCR percent relative peak areas successfully differentiated the microbial communities of rhizosphere and bulk soils of switchgrass and jatropha.

Switchgrass as a biofuels feedstock in the USA

2006 ◽  
Vol 86 (Special Issue) ◽  
pp. 1315-1325 ◽  
Author(s):  
M. A. Sanderson ◽  
P. R. Adler ◽  
A. A. Boateng ◽  
M. D. Casler ◽  
G. Sarath
Keyword(s):  
Panicum Virgatum ◽  
Management Practices ◽  
Biomass Energy ◽  
Perennial Grasses ◽  
Environmental Benefits ◽  
Energy Crop ◽  
Genetic Enhancement ◽  
Biomass Feedstock ◽  
Panicum Virgatum L ◽  
The Usa

Switchgrass (Panicum virgatum L.) has been identified as a model herbaceous energy crop for the USA. In this review, we selectively highlight current USDA-ARS research on switchgrass for biomass energy. Intensive research on switchgrass as a biomass feedstock in the 1990s greatly improved our understanding of the adaptation of switchgrass cultivars, production practices, and environmental benefits. Several constraints still remain in terms of economic production of switchgrass for biomass feedstock including reliable establishment practices to ensure productive stands in the seeding year, efficient use of fertilizers, and more efficient methods to convert lignocellulose to biofuels. Overcoming the biological constraints will require genetic enhancement, molecular biology, and plant breeding efforts to improve switchgrass cultivars. New genomic resources will aid in developing molecular markers, and should allow for marker-assisted selection of improved germplasm. Research is also needed on profitable management practices for switchgrass production appropriate to specific agro-ecoregions and breakthroughs in conversion methodology. Current higher costs of biofuels compared to fossil fuels may be offset by accurately valuing environmental benefits associated with perennial grasses such as reduced runoff and erosion and associated reduced losses of soil nutrients and organic matter, increased incorporation of soil carbon and reduced use of agricultural chemicals. Use of warm-season perennial grasses in bioenergy cropping systems may also mitigate increases in atmospheric CO2. A critical need is teams of scientists, extension staff, and producer-cooperators in key agro-ecoregions to develop profitable management practices for the production of biomass feedstocks appropriate to those agro-ecoregions. Key words: Bioenergy, biomass conversion technologies, Panicum virgatum L., stand establishment, switchgrass improvement, USDA-ARS

scholarly journals Internode structure and cell wall composition in maturing tillers of switchgrass (Panicum virgatum. L)

2007 ◽  
Vol 98 (16) ◽  
pp. 2985-2992 ◽  
Author(s):  
Gautam Sarath ◽  
Lisa M. Baird ◽  
Kenneth P. Vogel ◽  
Robert B. Mitchell
Keyword(s):  
Cell Wall ◽  
Panicum Virgatum ◽  
Cell Wall Composition ◽  
Panicum Virgatum L

Investigation of genomic organization in switchgrass (Panicum virgatum L.) using DNA markers

2005 ◽  
Vol 110 (8) ◽  
pp. 1372-1383 ◽  
Author(s):  
A M Missaoui ◽  
A H Paterson ◽  
J H Bouton
Keyword(s):  
Dna Markers ◽  
Panicum Virgatum ◽  
Genomic Organization ◽  
Panicum Virgatum L

scholarly journals Insect resistance of a full sib family of tetraploid switchgrass Panicum virgatum L. with varying lignin levels

2012 ◽  
Vol 60 (3) ◽  
pp. 975-984 ◽  
Author(s):  
Patrick F. Dowd ◽  
Gautam Sarath ◽  
Robert B. Mitchell ◽  
Aaron J. Saathoff ◽  
Kenneth P. Vogel
Keyword(s):  
Insect Resistance ◽  
Panicum Virgatum ◽  
Panicum Virgatum L
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