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At least 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

Plant growth during the Greenhouse II experiment on the Mir orbital station

We carried out three experiments with Super Dwarf wheat in the Bulgarian/Russian growth chamber Svet (0.1 m2 growing area) on the Space Station Mir. This paper mostly describes the first of these NASA-supported trials, began on Aug. 13, 1995. Plants were sampled five times and harvested on Nov. 9 after 90 days. Equipment failures led to low irradiance (3, then 4 of 6 lamp sets failed), instances of high temperatures (ca. 37 degrees C), and sometimes excessive substrate moisture. Although plants grew for the 90 d, no wheat heads were produced. Considering the low light levels, plants were surprisingly green, but of course biomass production was low. Plants were highly disoriented (low light, mirror walls?). Fixed and dried samples and the root module were returned on the U.S. Shuttle Atlantis on Nov. 20, 1995. Samples of the substrate, a nutrient-charged zeolite called Balkanine, were taken from the root module, carefully examined for roots, weighed, dried, and reweighed. The Svet control unit and the light bank were shipped to Moscow. An experiment validation test (EVT) of plant growth and experimental procedures, carried out in Moscow, was highly successful. Equipment built in Utah to measure CO2, H2O vapor, irradiance, air and leaf (IR) temperature, O2, pressure, and substrate moisture worked well in the EVT and in space. After this manuscript was first prepared, plants were grown in Mir with a new light bank and controller for 123 d in late 1996 and 39 days in 1996/1997. Plants grew exceptionally well with higher biomass production than in any previous space experiment, but the ca. 280 wheat heads that were produced in 1996 contained no seeds. Ethylene in the cabin atmosphere was responsible. c2002 Published by Elsevier Science Ltd on behalf of COSPAR.

Mir Project↗
NASA NTRS2002

Ionic signaling in plant responses to gravity and touch

Touch and gravity are two of the many stimuli that plants must integrate to generate an appropriate growth response. Due to the mechanical nature of both of these signals, shared signal transduction elements could well form the basis of the cross-talk between these two sensory systems. However, touch stimulation must elicit signaling events across the plasma membrane whereas gravity sensing is thought to represent transformation of an internal force, amyloplast sedimentation, to signal transduction events. In addition, factors such as turgor pressure and presence of the cell wall may also place unique constraints on these plant mechanosensory systems. Even so, the candidate signal transduction elements in both plant touch and gravity sensing, changes in Ca2+, pH and membrane potential, do mirror the known ionic basis of signaling in animal mechanosensory cells. Distinct spatial and temporal signatures of Ca2+ ions may encode information about the different mechanosignaling stimuli. Signals such as Ca2+ waves or action potentials may also rapidly transfer information perceived in one cell throughout a tissue or organ leading to the systemic reactions characteristic of plant touch and gravity responses. Longer-term growth responses are likely sustained via changes in gene expression and asymmetries in compounds such as inositol-1,4,5-triphosphate (IP3) and calmodulin. Thus, it seems likely that plant mechanoperception involves both spatial and temporal encoding of information at all levels, from the cell to the whole plant. Defining this patterning will be a critical step towards understanding how plants integrate information from multiple mechanical stimuli to an appropriate growth response.

Review↗
NASA NTRS1995

The components of crop productivity: measuring and modeling plant metabolism

Several investigators in the CELSS program have demonstrated that crop plants can be remarkably productive in optimal environments where plants are limited only by incident radiation. Radiation use efficiencies of 0.4 to 0.7 g biomass per mol of incident photons have been measured for crops in several laboratories. Some early published values for radiation use efficiency (1 g mol-1) were inflated due to the effect of side lighting. Sealed chambers are the basic research module for crop studies for space. Such chambers allow the measurement of radiation and CO2 fluxes, thus providing values for three determinants of plant growth: radiation absorption, photosynthetic efficiency (quantum yield), and respiration efficiency (carbon use efficiency). Continuous measurement of each of these parameters over the plant life cycle has provided a blueprint for daily growth rates, and is the basis for modeling crop productivity based on component metabolic processes. Much of what has been interpreted as low photosynthetic efficiency is really the result of reduced leaf expansion and poor radiation absorption. Measurements and models of short-term (minutes to hours) and long-term (days to weeks) plant metabolic rates have enormously improved our understanding of plant environment interactions in ground-based growth chambers and are critical to understanding plant responses to the space environment.

NASA Discipline Life Support Systems↗
DOE OSTI2024

Shape Optimization of Header Pipes in Power Plants for Enhanced Efficiency and Environmental Sustainability

In a power plant, the header pipe plays a pivotal role in optimizing the performance of diverse systems by serving as a central conduit for the collection and distribution of steam within the plant. This paper investigates the significance of header pipes within power plant setups, highlighting their critical influence on reliability, efficiency, and the performance of the power plant as a whole. The concept of shape optimization emerges as a crucial factor in power plant design and operation, with the potential to maximize performance while minimizing the use of materials. Shape optimization not only enhances efficiency but also contributes to reducing the environmental footprint of power plant installations. In this paper, we initially developed a methodology designed for optimizing header shapes with the primary goal of reducing the usage of costly new alloy materials and lowering the overall maintenance operation expenses. Secondly, we conducted a case study based on an authentic header sourced from an operational power plant.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2023

Cellulose Nanocrystals are a Renewable and Biocompatible Nanocarrier of Agrochemicals Directly to Plant Cells

More sustainable agricultural practices are critical to meeting humanity's food needs while minimizing adverse environmental impacts. Engineered nanomaterials used as nanocarriers promise to reduce the volume of agrochemicals required for crop production but concerns about nanocontamination of agricultural products necessitate the discovery of naturally occurring alternatives. Here, in this study, plant‐derived cellulose nanocrystals (CNC) as a “green” alternative to man‐made nanomaterials for the economical delivery of agrochemicals to plants are suggested. Using confocal microscopy and fluorescently labeled CNC, it is demonstrated that CNC can successfully penetrate the plant cell wall and enter cells without causing any negative effects on the overall plant phenotype, genome, and metabolome. The efficiency of CNC to deliver chemicals is demonstrated through in vitro tests involving CNC covalently conjugated with 2,4‐dichlorophenoxyacetic acid (2,4‐D). Plant cell culture experiments confirmed that CNC can be used as a 2,4‐D nanocarrier and reduces the volume of plant growth regulators needed to cultivate plant cells. This work creates a new platform for cyclical agricultural practices where CNC extracted from agricultural waste can be used for the direct delivery of agrochemicals to crops, thereby reducing the environmental burden created by both agricultural waste and excess herbicides.

Cellulose nanocrystals↗
DOE OSTI2025

Dual-mycorrhizal colonization is determined by plant age and host identity in two species of Populus

Plants have evolved symbioses with mycorrhizal and endophytic fungi that are essential for their growth and survival. While most plants associate with a single guild of mycorrhizal fungi, a select group termed “dual-mycorrhizal plants” associate with both arbuscular mycorrhizal and ectomycorrhizal fungi. Although a shift from predominance of arbuscular mycorrhizal to ectomycorrhizal colonization with plant development has been demonstrated on other dual-mycorrhizal hosts, it is not known how mycorrhizal colonization shifts with plant age in Populus species. We performed a controlled growth experiment with natural field-sourced inocula to test for age-dependent shifts in fungal colonization rates and for host-specific patterns of colonization in two species of Populus (P. tremuloides and P. trichocarpa). We found that only P. trichocarpa displayed dual-mycorrhizal colonization, while P. tremuloides associated with ectomycorrhizal fungi, but not arbuscular mycorrhizal fungi. Both guilds of mycorrhizal fungi increased in abundance with plant age, while root endophytic fungal colonization decreased. Many of the early-colonizing endophytic fungi that we documented have strong saprotrophic capabilities, which may be an important trait for fast colonization. Dark septate endophytes were more abundant than either guild of mycorrhizal fungi, and are likely to be functionally important members of the Populus root fungal community. Our findings represent a novel pattern in the development of dual-mycorrhizal colonization and illustrate that Populus species vary in their association with arbuscular mycorrhizal fungi. In conclusion, our results also highlight the importance of dark septate endophyte colonization dynamics on dual-mycorrhizal plants.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

A novel xylosylated fucoglucuronan in Penium reveals structural parallels to rhamnogalacturonan-I and its broad evolutionary footprint in lower plants

Green algae inhabit aquatic environments across the planet and play a crucial role in sustaining the global ecosystem. Ancestors of some Charophytes adapted to terrestrial conditions and eventually evolved into land plants. Extant green algae have inherited traits from their ancestors and evolved into their current morphological and chemical forms, as reflected by their cell walls with distinct shapes and compositions. To illuminate the evolution of plant cell walls and bridge the gap between green algae and land plants, we investigated the charophyte Penium margaritaceum, a close relative of terrestrial plants. We discovered a previously unknown polysaccharide in both its culture medium and cell wall. This polysaccharide, termed xylosylated fucoglucuronan (XFG), possesses a rhamnogalacturonan-I (RG-I)-like backbone composed of repeating [-3-α-Fucp-(1,4)-α-GlcpA-] disaccharides that are extensively xylosylated and acetylated. Surveying approximately 20 non-vascular plants revealed that XFG and RG-I (or related structures) first emerge in certain Chlorophyceae and subsequently co-occur throughout lineages along the evolutionary trajectory to bryophytes, thereby bridging aquatic green algae to early land plants. The striking structural parallels between XFG, RG-I, and ulvan suggest a shared evolutionary origin, offering new insight into how plant cell walls adapted during the transition from marine to freshwater environments and ultimately to land.

Algae↗
DOE OSTI2022

Data-driven modeling of power generation for a coal power plant under cycling

Increased penetration of renewables for power generation has negatively impacted the dynamics of conventional fossil fuel-based power plants. The power plants operating on the base load are forced to cycle, to adjust to the fluctuating power demands. This results in an inefficient operation of the coal power plants, which leads up to higher operating losses. To overcome such operational challenge associated with cycling and to develop an optimal process control, this work analyzes a set of models for predicting power generation. Moreover, the power generation is intrinsically affected by the state of the power plant components, and therefore our model development also incorporates additional power plant process variables while forecasting the power generation. We present and compare multiple state-of-the-art forecasting data-driven methods for power generation to determine the most adequate and accurate model. We also develop an interpretable attention-based transformer model to explain the importance of process variables during training and forecasting. The trained deep neural network (DNN) LSTM model has good accuracy in predicting gross power generation under various prediction horizons with/without cycling events and outperforms the other models for long-term forecasting. The DNN memory-based models show significant superiority over other state-of-the-art machine learning models for short, medium and long range predictions. The transformer-based model with attention enhances the selection of historical data for multi-horizon forecasting, and also allows to interpret the significance of internal power plant components on the power generation. This newly gained insights can be used by operation engineers to anticipate and monitor the health of power plant equipment during high cycling periods.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2023

Land-use history, fire regime, and large-mammal herbivory affect deer-preferred plant diversity in longleaf pine woodlands

Since ecological systems often experience multiple disturbances, understanding changes in important ecological interactions, such as plant-herbivore interactions, may require studies capable of disentangling the unique and interactive effects of multiple forms of disturbance. For example, understanding how mammalian herbivores affect plant communities may require understanding how widespread past disturbances, such as agricultural land use, interact with contemporary disturbances, such as prescribed fire. Here, we tested if past agricultural land use and contemporary fire regime modified the effects of mammalian herbivory on focal plant communities by measuring the richness of plant species preferred by deer at 26 longleaf pine woodlands containing paired open and large-mammal exclusion plots. Land-use history significantly affected the community composition of deer-preferred species, and focal species were 8.19 times more likely to be present in post-agricultural sites than non-agricultural sites. Large-mammal herbivory only affected plant species richness in woodlands with low fire frequencies wherein focal species were on average 2.23 times more likely to be present in exclusion plots than open plots. These results suggest that past and present disturbances can mediate contemporary plant-animal interactions and may explain spatial patterns in the intensity of large-mammal herbivory. Our findings also suggest that common management practices, such as use of prescribed burns, may indirectly promote plant species richness by reducing deer herbivory.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Multicriterion benefit evaluation methodology for safety enhancements in nuclear power plants and application for FLEX strategies

Here we propose a multicriterion benefit evaluation (MCBE) methodology for evaluating costs and benefits of implementing safety enhancements in nuclear power plants. The MCBE methodology establishes a comprehensive evaluation scope using multiple evaluation criteria (including public risk, occupational risk, plant revenue, and plant cost) and multiple contexts (including plant normal operations, incidents, and accidents). The MCBE methodology formulates a benefit or cost element as the product of a monetary consequence and its occurrence-likelihood change. The MCBE methodology also incorporates a decision maker’ preferences toward occurrence likelihood and monetary consequence into cost and benefit estimations through a modified usage of cumulative prospect theory. This paper applies the MCBE methodology to the implementation of diverse and flexible coping strategy (FLEX) in a generic nuclear power plant as an illustrative example. The FLEX benefits are evaluated through three types of influence paths: plant safety enhancement, risk-informed activities, and potential additional credit of FLEX in supporting plant operation and maintenance-efficiency improvement. The benefit-to-cost ratio (BCR) of FLEX implementation is calculated. Sensitivity analyses are conducted to examine the impacts of modeling assumptions and input parameter values on the BCR.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2021

Integrating Arctic Plant Functional Types in a Land Surface Model Using Above‐ and Belowground Field Observations

Abstract Accurate simulations of high‐latitude ecosystems are critical for confident Earth system model (ESM) projections of carbon cycle feedbacks to global climate change. Land surface model components of ESMs, including the E3SM Land Model (ELM), simulate vegetation growth and ecosystem responses to changing climate and atmospheric CO 2 concentrations by grouping heterogeneous vegetation into like sets of plant functional types (PFTs). Many such models represent high‐latitude vegetation using only two PFTs (shrub and grass), thereby missing the diversity of vegetation growth forms and functional traits in the Arctic. Here, we use field observations of biomass and leaf traits across a gradient of plant communities on the Seward Peninsula in northwest Alaska to replace the original ELM configuration for the first time with nine Arctic‐specific PFTs. The newly developed PFTs include: (1) nonvascular mosses and lichens, (2) deciduous and evergreen shrubs of various height classes, including an alder PFT, (3) graminoids, and (4) forbs. Improvements relative to the original model configuration included greater belowground biomass allocation, persistent fine roots and rhizomes of nonwoody plants, and better representation of variability in total plant biomass across sites with varying plant communities and depth to bedrock. Simulations through 2100 using the RCP8.5 climate scenario and constant PFT fractional areas showed alder‐dominated plant communities gaining more biomass and lichen‐dominated communities gaining less biomass compared to default PFTs. Our results highlight how representing the diversity of arctic vegetation and confronting models with measurements from varied plant communities improves the representation of arctic vegetation in terrestrial ecosystem models.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Logistics of defense: The contribution of endomembranes to plant innate immunity

Phytopathogens cause plant diseases that threaten food security. Unlike mammals, plants lack an adaptive immune system and rely on their innate immune system to recognize and respond to pathogens. Plant response to a pathogen attack requires precise coordination of intracellular traffic and signaling. Spatial and/or temporal defects in coordinating signals and cargo can lead to detrimental effects on cell development. The role of intracellular traffic comes into a critical focus when the cell sustains biotic stress. In this review, we discuss the current understanding of the post-immune activation logistics of plant defense. Specifically, we focus on packaging and shipping of defense-related cargo, rerouting of intracellular traffic, the players enabling defense-related traffic, and pathogen-mediated subversion of these pathways. We highlight the roles of the cytoskeleton, cytoskeleton–organelle bridging proteins, and secretory vesicles in maintaining pathways of exocytic defense, acting as sentinels during pathogen attack, and the necessary elements for building the cell wall as a barrier to pathogens. We also identify points of convergence between mammalian and plant trafficking pathways during defense and highlight plant unique responses to illustrate evolutionary adaptations that plants have undergone to resist biotic stress.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Imaging plant metabolism in situ

Abstract Mass spectrometry imaging (MSI) has emerged as an invaluable analytical technique for investigating the spatial distribution of molecules within biological systems. In the realm of plant science, MSI is increasingly employed to explore metabolic processes across a wide array of plant tissues, including those in leaves, fruits, stems, roots, and seeds, spanning various plant systems such as model species, staple and energy crops, and medicinal plants. By generating spatial maps of metabolites, MSI has elucidated the distribution patterns of diverse metabolites and phytochemicals, encompassing lipids, carbohydrates, amino acids, organic acids, phenolics, terpenes, alkaloids, vitamins, pigments, and others, thereby providing insights into their metabolic pathways and functional roles. In this review, we present recent MSI studies that demonstrate the advances made in visualizing the plant spatial metabolome. Moreover, we emphasize the technical progress that enhances the identification and interpretation of spatial metabolite maps. Within a mere decade since the inception of plant MSI studies, this robust technology is poised to continue as a vital tool for tackling complex challenges in plant metabolism.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

The N-terminal domains of NLR immune receptors exhibit structural and functional similarities across divergent plant lineages

Nucleotide-binding domain and leucine-rich repeat (NLR) proteins are a prominent class of intracellular immune receptors in plants. However, our understanding of plant NLR structure and function is limited to the evolutionarily young flowering plant clade. Here, we describe an extended spectrum of NLR diversity across divergent plant lineages and demonstrate the structural and functional similarities of N-terminal domains that trigger immune responses. We show that the broadly distributed coiled-coil (CC) and toll/interleukin-1 receptor (TIR) domain families of nonflowering plants retain immune-related functions through translineage activation of cell death in the angiosperm Nicotiana benthamiana. We further examined a CC subfamily specific to nonflowering lineages and uncovered an essential N-terminal MAEPL motif that is functionally comparable with motifs in resistosome-forming CC-NLRs. Consistent with a conserved role in immunity, the ectopic activation of CC MAEPL in the nonflowering liverwort Marchantia polymorpha led to profound growth inhibition, defense gene activation, and signatures of cell death. Moreover, comparative transcriptomic analyses of CC MAEPL activity delineated a common CC-mediated immune program shared across evolutionarily divergent nonflowering and flowering plants. Collectively, our findings highlight the ancestral nature of NLR-mediated immunity during plant evolution that dates its origin to at least ~500 million years ago.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

PiCAM: A Raspberry Pi-based open-source, low-power camera system for monitoring plant phenology in Arctic environments

Time-lapse cameras have been widely used as a tool to monitor the timing of seasonal vegetation growth. These simple, relatively inexpensive systems can provide high-frequency observations of leaf development and demography which are critical data sets needed to characterize plant phenology from species to landscapes. This is important for understanding how plants are responding to global changes, as well as for validating satellite-derived phenology products. However, in remote regions including the high-latitude Arctic, deploying time-lapse cameras could be challenging. The remoteness and lack of widespread power and telecommunications infrastructure limit options for the installation, maintenance and retrieval of data and equipment, and make it difficult for cameras to survive in extreme weather (e.g. long cold winters). To improve our understanding of Arctic phenology, new technologies are required to address these challenges. Here, we present a novel, low-power, compact, lightweight time-lapse camera system, called power-interval camera automation module (PiCAM). The PiCAM was designed with explicit consideration to simplify deployment (i.e. without a need for external power supplies) of camera systems and to address the challenges of camera survival in harsh Arctic environments. In this paper, we describe the design, setup and technical details of the PiCAM and provide a roadmap for how to build and operate these systems. As proof of concept, we deployed 26 PiCAMs at three low-Arctic tundra sites on the Seward Peninsula, Alaska in early August 2021 for characterizing Arctic plant phenology. Of the 26 PiCAMs, 70% remained active at the point of our revisit in late July 2022 despite the extreme winter temperatures they experienced (< –30°C, heavy snow cover). We extracted key plant phenology metrics from the PiCAMs and captured strong differences across key Arctic plant species. We showed that the PiCAM has the potential to be widely used for monitoring plant phenology across the broader Arctic region, addressing the need for ground-based understanding of Arctic phenological diversity to develop knowledge of plant response to climate change and to validate remote sensing products.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Advances in Miscanthus × Giganteus Planting Techniques May Increase Carbon Uptake in the Establishment Year

Agricultural lands hold significant potential for CO 2 sequestration, particularly when utilizing biomass crops and agricultural residues. Among these, Miscanthus × giganteus (mxg) stands out due to its high productivity and carbon sequestration capabilities. Recognizing the importance of such biomass crops, the Intergovernmental Panel on Climate Change (IPCC) has identified Bioenergy with Carbon Capture and Storage (BECCS) as a crucial strategy for achieving net-zero CO 2 emissions by 2050. This study examines the carbon uptake potential of mxg during its establishment year at the Sustainable Advanced Bioeconomy Research (SABR) farm in Iowa, USA, where mxg was planted at a density exceeding previous studies. Using eddy covariance (EC) measurements, we quantified the net ecosystem carbon exchange (NEE), and derived gross primary productivity (GPP), and ecosystem respiration (R eco ). Our findings reveal that SABR's mxg exhibited a significant carbon uptake of –621 g C m –2 , a threefold increase compared to a similar EC site in the “corn-belt” (University of Illinois Energy Research Farm; UIEF), which was established with lower planting density and pre-commercial planting equipment. Favorable growing conditions and advanced planting technologies at SABR likely contributed to this high carbon uptake. Comparisons with other global EC studies indicated a strong correlation between higher planting densities and greater carbon uptake. These results suggest that increasing mxg planting density can enhance carbon uptake, but further studies are necessary to evaluate the impacts under varying environmental conditions and management practices. Additionally, economic analyses are essential to determine the viability of higher planting densities. Our study underscores the potential of optimized mxg management practices to contribute significantly to CO 2 uptake and supports the development of BECCS as a viable climate change mitigation strategy.

09 BIOMASS FUELS↗
DOE OSTI2025

A split ribozyme system for in vivo plant RNA imaging and genetic engineering

RNA plays a central role in plants, governing various cellular and physiological processes. Monitoring its dynamic abundance provides a discerning understanding of molecular mechanisms underlying plant responses to internal (developmental) and external (environmental) stimuli, paving the way for advances in plant biotechnology to engineer crops with improved resilience, quality and productivity. In general, traditional methods for analysis of RNA abundance in plants require destructive, labour-intensive and time-consuming assays. To overcome these limitations, we developed a transformative innovation for in vivo RNA imaging in plants. Specifically, we established a synthetic split ribozyme system that converts various RNA signals to orthogonal protein outputs, enabling in vivo visualisation of various RNA signals in plants. We demonstrated the utility of this system in transient expression experiments (i.e., leaf infiltration in Nicotiana benthamiana ) to detect RNAs derived from transgenes and tobacco rattle virus, respectively. Also, we successfully engineered a split ribozyme-based biosensor in Arabidopsis thaliana for in vivo visualisation of endogenous gene expression at the cellular level, demonstrating the feasibility of multi-scale (e.g., cellular and tissue level) RNA imaging in plants. Furthermore, we developed a platform for easy incorporation of different protein outputs, allowing for flexible choice of reporters to optimise the detection of target RNAs.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Evolutionary History of Plant Metabolism

Tremendous chemical diversity is the hallmark of plants and is supported by highly complex biochemical machinery. Plant metabolic enzymes originated and were transferred from eukaryotic and prokaryotic ancestors and further diversified by the unprecedented rates of gene duplication and functionalization experienced in land plants. Unlike microbes, which have frequent horizontal gene transfer events and multiple inputs of energy and organic carbon, land plants predominantly rely on organic carbon generated from CO 2 and have experienced very few, if any, gene transfers during their recent evolutionary history. As such, plant metabolic networks have evolved in a stepwise manner and on existing networks under various evolutionary constraints. This review aims to take a broader view of plant metabolic evolution and lay a framework to further explore evolutionary mechanisms of the complex metabolic network. Understanding the underlying metabolic and genetic constraints is also an empirical prerequisite for rational engineering and redesigning of plant metabolic pathways.

Plant Sciences↗